Dental Caries

Dental caries is a multifactorial disease process that cause demineralization of tooth enamel. If the process is not reversed through remineralization, the enamel is weakened and then destroyed, forming a cavity that, if left untreated, can cause pain, infection, and tooth loss. (Divaris 2016; Pitts et al. 2017). For more information on what causes caries, see Section 2 of this monograph, which focuses on oral health in children and adolescents. Untreated tooth decay continues to be a major cause of tooth loss in adults. In 2015, untreated tooth decay cost about $45.9 billion in lost productivity in the United States (Righolt et al. 2018).

Dental caries is not just a disease of childhood. At least 9 out of 10 working-age adults have experienced tooth decay in their permanent teeth (Centers for Disease Control and Prevention 2019a). Although it has decreased since the early 1970s, the prevalence of dental caries in adults remains widespread. On average, working-age adults have 9 permanent teeth decayed, missing, or filled because of dental disease. Based on data from 2011–2016, more than 1 in 4 working-age adults had untreated tooth decay (26%), with significant disparities by race/ethnicity and income. Just 22% of non-Hispanic White adults had untreated decay, compared to 37% of Mexican Americans and 40% of non-Hispanic Blacks. Among adults with a household income at least twice the federal poverty level, 18% had untreated decay, compared with 41% of adults with lower household incomes (Centers for Disease Control and Prevention 2019a). Untreated tooth decay also is highest among those aged 20 to 34 years (29%) and lowest among those aged 50 to 64 years (22%), which sets the stage for dental caries as a highly prevalent chronic disease throughout adulthood.

Periodontal Disease

Periodontitis is an oral infection characterized by inflammation of the gums and supporting structures of the teeth. As the inflammation intensifies, periodontal pockets can form (creating spaces between the teeth and gums) that lead to infection and progressive bone loss (Figure 2). In advanced stages, it can lead to sore and bleeding gums, painful chewing problems, and tooth loss. There are several forms of periodontitis, but the more common forms include aggressive periodontitis, chronic periodontitis, necrotizing periodontitis, and periodontitis manifesting as a result of systemic disease (Caton et al. 2018a; 2018b). Globally, periodontitis is the sixth most prevalent disease worldwide, affecting an estimated 740 million people (Kassebaum et al. 2014; Murray et al. 2014). Its functional impact can be measured in terms of pain, discomfort, and difficulty in chewing.

Figure 2

Important anatomical changes associated with periodontal disease progression.

Changes in facial appearance can impair social interaction, as can the halitosis (bad breath) that often accompanies the condition. Recent research shows that periodontitis and associated inflammation are risk factors for noncommunicable chronic diseases such as cardiovascular disease, diabetes mellitus, respiratory disease, and cognitive impairment (Bansal et al. 2013; Teixeira et al. 2017; Cardoso et al. 2018; Liccardo et al. 2019). The identification of periodontitis as a risk factor for these diseases has elevated its significance from a local disorder in the mouth to a more systemic disease with general health implications. Mechanisms to account for the systemic effects of periodontitis focus on the direct and indirect effects of periodontal bacteria gaining access to the body’s circulation system and increasing the systemic inflammatory burden through effects on the liver or by direct infection of specific organs and tissues (Hajishengallis and Chavakis 2021).

Periodontitis is an important oral disease of adulthood, with prevalence increasing with age (Billings et al. 2018a; 2018b). An estimated 42% of the U.S. population has periodontitis, and 8% have severe periodontitis (Table 1). The prevalence of severe periodontitis is greater for men than women and is higher for Mexican Americans and non-Hispanic Blacks, compared to non-Hispanic Whites. Current smoking is an important risk factor for severe periodontitis among working-age adults. People with diabetes and those with an income below 100% of the federal poverty level also are at increased risk for both severe and moderate periodontal disease (Eke et al. 2018). Periodontitis is an important public health problem and a leading cause of tooth loss in the United States today (National Institute of Dental and Craniofacial Research 2018a).

Table 1

Percentage of adults age 30 and older with periodontitis by select characteristics: United States, 2009–2014.

Tooth Loss

Tooth loss affects adults of all ages, but complete tooth loss (edentulism) is rare among working-age adults in the United States today; just 2.2% of adults aged 20 to 64 years were edentulous in 2011–2016. Edentulism was higher among adults who were poor (6%), had less than a high school education (5%), and were current smokers (6%) (Centers for Disease Control and Prevention 2019a). Among older working-age adults (50–64 years of age), an estimated 6% are edentulous (without teeth), with more than 17% of those living in poverty experiencing complete tooth loss (Dye et al. 2019a). In the United States, significant tooth loss (having six or more missing teeth) affects the populations of some regions of the country more than others. For example, Appalachia, followed by the Mississippi Delta, have the highest levels of significant tooth loss among working-age adults (Gorsuch et al. 2014). An important concept that relates tooth loss to quality of life is a functional dentition, which is typically defined as having 21 or more teeth, excluding third molars. Three in four older working-age adults in the United States have a functional dentition, but substantial oral health disparities exist by socioeconomic indicators. Among those living in poverty, about 47% have a functional dentition, whereas 83% of nonpoor adults 50 to 64 years of age have a functional dentition (Dye et al. 2019a).

Oral Cavity and Oropharyngeal Cancer

Oral cavity cancers affect areas within the mouth that include the lips, the inner lining of the cheeks, the gums, most of the tongue, the area of the mouth below the tongue, and the hard bony area forming the roof of the mouth. OPCs affect the pharynx, back of the tongue, soft palate, side and back walls of the throat, and tonsils. See Figure 1 for a visual description of these areas. Some common signs of oral cavity cancer include a sore that does not heal, inflamed patches, or other changes in the lips, mouth, or cheek, such as a mass or persistent swelling (Huber and Tantiwongkosi 2014). For OPCs, the most common sign is a sore throat or enlarged lymph node (lump or mass in the neck). However, OPCs are often indolent and cannot be easily recognized (National Cancer Institute 2020a). Because these tumors reside inside the mouth and throat, dental clinicians often are the first caregivers to detect them (National Institute of Dental and Craniofacial Research 2018b).

Both oral cavity and oropharyngeal cancers continue to be a public health concern because of debilitation and disfigurement, as well as high mortality rates (Mignogna et al. 2004).

In 2019, there were an estimated 54,010 cases of oral cavity or oropharyngeal cancer in the United States, with 10,850 deaths (American Cancer Society 2021). More than 38,000 of these cases were in men, and an estimated 250,000 men were survivors of this type of cancer (Miller et al. 2019). Among all cancer cases of the oral and pharyngeal areas, the most frequent age at diagnosis for adults is between 55 to 64 years of age (National Cancer Institute 2020b). The age-adjusted incidence for oral and pharyngeal cancer, about 11 per 100,000 in 2012–2016, has been increasing by an average of 0.8% per year during the last decade (Howlader et al. 2019).

Currently, the mortality rate is about 2.5 per 100,000 (Figure 3), with an age adjusted 5-year survival rate of 66% for all OPC patients (National Cancer Institute 2020b). Survival rate ranges from better than 80% if the cancer diagnosed is confined within the primary site to about 40% if the cancer has metastasized (Figure 4). Unfortunately, the majority of these cancers are diagnosed after some spread has occurred. Generally, African American adults’ overall survival is lower compared to White adults for cancers of the oral cavity and pharynx (Ang et al. 2010; Zandberg et al. 2016). Although racial disparities persist in overall survival for cancers not associated with HPV, it seems that racial differences observed in overall survival for HPV-OPC are not significant (Stein et al. 2020). This suggests that other social determinants of health (SDoH) may influence overall survival in OPC caused by HPV infection.

Figure 3

Incidence and mortality rates for oral cavity and pharynx cancer: United States, 1992–2018. Notes: New cases come from SEER 13. Deaths come from U.S. mortality. All races both sexes. Rates are age adjusted.

Figure 4

Percent of cases and 5-year relative survival by stage at diagnosis for oral cavity and pharynx cancer: United States, 2011–2017. Notes: SEER 18 2011–2017, all races, both sexes by SEER summary stage 2000.

In addition to cancers of the oral cavity and pharynx, other oral disorders with malignant potential are oral mucosal lesions and conditions with unclear etiology. They include leukoplakias, erythroplakias, and other disorders with increased malignant potential (Warnakulasuriya et al. 2007). Leukoplakias are the most prevalent among these, at approximately 1–5% (Petti 2003), and their annual risk for malignant transformation is 2–3% (van der Waal 2014).

Oral Human Papillomavirus

There are more than 100 kinds of HPV, 13 of which are considered cancer causing. HPV16 causes more than 90% of cases of HPV-related oropharyngeal squamous cell cancer (HPV-OPC) in the United States. Other HPV types (18, 33, and 35) are responsible for a smaller subset of HPV-OPC, with each detected in less than 1% of HPV-OPC cases (Stein et al. 2015).

The proportion of OPC caused by HPV has increased dramatically during the past 25 years, from 35% of OPC between 1995–1999 to 75% between 2010–2012 (Chaturvedi et al. 2011; D’Souza et al. 2017a). This change is due both to a decrease in tobacco-related OPC, reflecting decreased tobacco use, and an increase in HPV-OPC. Although the vast majority of OPCs are now caused by HPV, only a small proportion (less than 5%) of oral cavity (mouth) squamous cell cancers are caused by HPV (Castellsague et al. 2016; D’Souza et al. 2017a).

HPV16 is the most common oral HPV type. Oral HPV16 DNA is detected in about 1% of U.S. adults (Gillison et al. 2012) and the lifetime risk of OPC is low (37 per 10,000) (D’Souza et al. 2017b). The primary risk factor for oral HPV is performing oral sex. The prevalence of oral HPV increases with higher numbers of lifetime oral sex partners (Gillison et al. 2012). Oral HPV is more common among men than women and among people who currently use tobacco (Chaturvedi et al. 2015; Sonawane et al. 2017). Figure 5 outlines the risk for oral HPV infection based on the key risk factors.

Figure 5

What is your risk for oral HPV? HPV = human papillomavirus; OncHPV = potentially cancer-causing HPV; HPV16 = most common high-risk type of HPV

Evidence suggests that many people are exposed to oral HPV in their lifetime. About 5–7% of men acquire a new oral HPV infection each year (Kreimer et al. 2013; Wood et al. 2017), but incidence of oral HPV16, specifically, is about 1% in men per year and lower than that in women. The per-partner risk of oral HPV infection appears to be higher among men than women (Chaturvedi et al. 2015; D’Souza et al. 2016), although reasons for this difference are not yet understood.

Most oral HPV infections clear on their own within 1 to 2 years, and most people are not even aware of their infection (D’Souza et al. 2016; Wood et al. 2017).

Among American men in their fifties, for example, 8.1% have a prevalent, cancer-causing oral HPV infection, and 2.1% have a prevalent oral HPV16 infection, yet only 0.7% of them will develop OPC in their lifetime (D’Souza et al. 2017b). Of the oral HPV types, HPV16 is not only the most prevalent but also is the most likely to persist (Kjaer et al. 2010; Gargano et al. 2012; Sand et al. 2019).

Although there are two HPV vaccines approved by the U.S. Food and Drug Administration, only one vaccine currently is used in the United States. The Gardasil^® 9 vaccine (U.S. Food and Drug Administration 2020) is approved for people through 45 years of age. The current recommendation in the United States for HPV vaccination is for boys and girls 11 to 12 years of age. The Advisory Committee on Immunization Practices (ACIP) also recommends HPV vaccine for all adults through 26 years of age. Although vaccination is not routinely recommended for adults aged 27 to 45, a medical review and discussion with the patient could lead to a decision that vaccination would be beneficial (Meites et al. 2019). Recognizing the important role HPV has in oral health, in 2018 the ADA adopted a policy that urges dentists to support the use and administration of the HPV vaccine (American Dental Association 2018a). One year later, Oregon became the first state to pass legislation allowing dentists to provide vaccinations, including vaccinations for seasonal flu and HPV (Walker et al. 2019). More information on HPV and vaccination is discussed in Section 2B.

Orofacial Pain and Temporomandibular Joint Disorders

Orofacial pain can greatly reduce quality of life. This type of pain may be because of tooth-related infections, mucosal sores, or irritations, and may include burning sensations, pain in the jaw joint area, or aching pain across the face or cheek. Data from 30 years ago indicated about 12% of adults in the United States reported having a toothache and about 5% had jaw joint pain (Lipton et al. 1993). Although contemporary estimates are not available, a more recent regional study reported that 1 in 6 patients visit the dentist because of orofacial pain, with toothache being the most common, closely followed by temporomandibular joint disorder (TMD) pain (Horst et al. 2015). In general, there are three types of orofacial pain: dental-related pain, TMD pain, and non-TMD pain (Okeson 2019). Dental-related pain includes pain associated with the tooth’s pulp or surrounding periodontal structure. TMD pain is broadly defined as musculoskeletal pain affecting the masticatory system (jaw), is most commonly of either joint or muscle origin, and can be classified into five groupings: masticatory muscle disorders, TMD, inflammatory disorders, chronic mandibular hypomobility, and growth disorders (Okeson 2019). Non-TMD pain represents a large category of orofacial pains that include migraine and trigeminal neuralgia (TN), among others.

Temporomandibular joint and muscle disorders are conditions characterized by pain affecting the temporomandibular jaw joint and masticatory muscles in the temporomandibular region (Figure 6) (Dworkin and LeResche 1992). They also involve such functional problems as jaw opening limitations, deviant jaw patterns, and joint sounds (Laskin et al. 1983). The personal and societal impact of TMD is primarily because of its status as a chronic/recurrent pain condition, and pain is the main reason that patients seek treatment for TMD (Dworkin et al. 1990).

Figure 6

Temporomandibular region.

In one study, the prevalence of adults reporting pain in the temporomandibular region over the previous week was approximately 5% (Lovgren et al. 2016), while about 12% of adults reported such pain in the previous 6 months (Von Korff et al. 1988). Among older adolescents and adults, the prevalence of TMD pain rises with age, peaking at 18–25% of the population (Dworkin and LeResche 1992) at about 40 years of age, and then declining. The few available studies on racial/ethnic differences suggest that TMD incidence (Slade et al. 2013a) and age-specific prevalence patterns (Plesh et al. 2011) may differ for African Americans and Hispanics, with later age of onset than for Whites.

TN is a less common pain syndrome but is reportedly one of the most painful facial conditions. Symptoms are severe shooting or jabbing pain that often is described as feeling like electrical shocks. Little is known about the etiology of this condition. Its prevalence ranges from 0.03–0.3%, with women having a three times higher prevalence than men, and those aged 37 to 65 years having the highest prevalence (De Toledo et al. 2016). The cost of treating TN in the United States exceeded $94 million between 2003 and 2013 (Holland et al. 2015). Additional information on orofacial pain is provided in Section 5.

Dental Fear and Anxiety

Fear and anxiety related to dental care are distressing emotional responses, typically characterized by a combination of physiological reaction (e.g., increased heart rate, perspiration), worry or rumination, feelings of apprehension or dread, and avoidance of treatment (McNeil et al. 2011). Causes and manifestations of dental fear/anxiety are highly individualized, with experiences along a continuum, ranging from fearfulness to phobia (McNeil et al. 2011).

Nearly 20% of U.S. adults experience moderate to high dental fear/anxiety, and an estimated 7% experience high fear/anxiety (White et al. 2017). These estimates are relatively consistent with those documented since the 1950s (Smith and Heaton 2003). It is somewhat discouraging that even as dental care access and quality have increased, fear/anxiety has persisted in the United States, while decreasing in other countries (Svensson et al. 2016).

Dental Erosion and Tooth Wear

Ongoing damage to a tooth’s enamel is not limited to the dental caries process alone. Tooth wear as a result of erosive or abrasive etiological factors is not uncommon among adults, with a global prevalence for any form of tooth wear in permanent teeth ranging from 20–45% (Bartlett and O’Toole 2020). Dental erosion is the irreversible, acid-induced loss or wear of dental hard tissues, not involving bacterial-secreted acids associated with dental caries (Ganss 2014). Dental erosion can result from extrinsic factors (acidic diet) or from intrinsic factors (acidic content of the stomach). In children, dental erosion is most often caused by dietary acids from juice, soda, fresh fruit, and sour candies. In adults, although dietary acids also may cause dental erosion, it more often is associated with gastroesophageal reflux disease (GERD), especially if it affects molar occlusal surfaces (Pace et al. 2008; Ranjitkar et al. 2012; Al-Zwaylif et al. 2018). Identifying GERD is important because the risk of developing esophageal adenocarcinoma later in life is approximately 43 times greater in individuals with untreated GERD than in those without GERD (Lagergren et al. 1999).

Other forms of tooth wear (abrasion) can result from intrinsic factors (tooth grinding) or from extrinsic factors, such as frequent use of highly abrasive oral care products or frequent consumption of a diet high in abrasive foods. Tooth wear is associated with increasing age in adults (Van’t Spijker et al. 2009). Findings from a practice-based research network in the Northwestern United States reported that among adult participants, about half had at least four teeth with some indication of moderate tooth wear (Cunha-Cruz et al. 2010). Those who were older, male, and had some periodontal bone loss were more likely to have moderate or severe tooth wear. Although there is sufficient evidence to support our understanding of the etiology of erosive and abrasive tooth wear, there is little evidence to support clinical decision making on when to intervene or what the long-term effectiveness of interventions may have on oral health-related quality of life (OHRQoL) (Bartlett and O’Toole 2020).

Dental Trauma

Dental trauma can occur in different forms, from injury that has caused the tooth to become displaced from its normal position but retained in the jaw bone with some mobility, tenderness, or pain, to full avulsion (in which a tooth has been “knocked out”). In addition, injury could cause the tooth to have a complete fracture, resulting in portions of the dental crown or root experiencing a complete break (Figure 7, D, F, G). Incomplete or uncomplicated crown fractures affecting permanent teeth (often known as a cracked tooth) are the most common type of dental injury among adults (Figure 7, B, C, E). Because incomplete tooth fracture often is difficult to assess and often is perceived as not requiring attention, epidemiologic assessments most likely substantially underreport dental trauma (Lam 2016) and when reported, can lead to far-ranging prevalence estimates. For example, cracked teeth (or incomplete tooth fracture) has been previously reported to be between 34–74% (Cameron 1964; Hiatt 1973).

Figure 7

Tooth cracks and fractures. Notes: Examples of typical cracks and fractures affecting teeth. (A) Small visible fracture lines in coronal area only (Craze lines) in central incisor.

Teeth can develop cracks from a variety of causes, including biting down too strenuously on a very hard food item or object, tooth grinding, physical trauma, and oversized dental restorations (Table 2) (Hasan et al. 2015). Cracks are difficult for dentists to diagnose because many of them are hard to detect, even while employing a variety of techniques using magnifying lenses, a dental explorer, a periodontal probe, dyes, vitality tests, or transillumination. Radiographs enable a dentist to eliminate other pathologies and are useful in detecting cracks that run from the cheek (buccal) to the tongue (lingual) sides of the tooth (Hasan et al. 2015). Although tooth cracks are common and most are harmless, others may cause symptoms that require treatment. These symptoms can include pain when chewing; sensitivity to cold, heat, and sweets, and swelling in the gums around the tooth. Pain also can occur when pressure from biting is relieved (“rebound” pain). Painful symptoms characterize a condition called “cracked tooth syndrome” (Nguyen and Palmer 2010). Depending on the size and location of the crack, treatments vary from no treatment (Hilton et al. 2020), to minor adjustments of the biting surface of the tooth, to restorations that vary in size and materials. If the crack is extensive, removal of the tooth may be the only possible option (Bader et al. 1995; Nguyen and Palmer 2010).

Table 2

Etiological factors in cracked tooth syndrome.

Complete tooth fractures occur when the fractured parts of the tooth move independently of one another and can result from the same situations that cause cracked teeth (Hasan et al. 2015). They usually require treatments similar to those used for cracked tooth syndrome, but an estimated 15% involve the tooth pulp and can result in extractions (Bader et al. 1995).

Tobacco Product Use

Based on data from 2019, an estimated 50.6 million U.S. adults (20.8%) were using a tobacco product (cigarettes; cigars, cigarillos, or filtered little cigars; waterpipe tobacco; e-cigarettes; and smokeless tobacco), with 14% exclusive cigarette smokers and 18.6% using two or more tobacco products. Among those who were using tobacco products, most (80.5%) reported using combustible products (cigarettes, cigars, or pipes) (Cornelius et al. 2020). Comparing age groups, cigar use was higher among young adults (18–24 years of age) at 14%, primarily driven by flavored cigars. Males (13%) were more likely to smoke cigars than females (3%), as were non-Hispanic Blacks (12%) and non-Hispanics of two or more races (15%). Furthermore, some subgroups of the lesbian, gay, bisexual, transgender, and queer population (16% bisexual; 11% gay/lesbian) were more likely to smoke cigars than their heterosexual counterparts, at 8% (Kasza et al. 2017).

The prevalence of waterpipe tobacco smoking (WPS), or hookah use, is gradually rising in the United States. The combination of water-cooled and flavored tobacco smoke, as well as an incorrect perception of safety, has contributed to this increase (Smith-Simone et al. 2008; Cobb et al. 2010; Maziak et al. 2011; Jaff and Kumar 2016). WPS prevalence among adults increased from 0.6% to 1% between 2013 and 2019 (Hu et al. 2016; Cornelius et al. 2020). In 2019, WPS was the most commonly used tobacco product after e-cigarettes among younger people aged 18 to 24 years, and current cigarette smokers, as well as men, non-Hispanics, and sexual minorities also were more likely to use waterpipe tobacco (Cornelius et al. 2020).

Meanwhile, e-cigarette use among adults in the United States has fluctuated since their introduction in the early 2000s. Current e-cigarette use, for example, grew from 0.3% in 2010 to 6.8% in 2013 (McMillen et al. 2014), before falling to 3.7% in 2014 and climbing to 4.5% in 2019 (Delnevo et al. 2016; Cornelius et al. 2020). Data from 2017 suggest that 30% of U.S. adult combustible tobacco users also used e-cigarettes. The prevalence of exclusive e-cigarette use was nearly 3% that year, with relatively higher use among young adults, sexual minorities, and those living in the Midwest and South (Wang et al. 2018). Users of e-cigarettes are nearly three times more likely to have gingivitis than nonsmokers (Vora and Chaffee 2019). Other reported oral health consequences of e-cigarettes include oral-facial injuries resulting from overheating and explosion of e-cigarette devices, including tooth fractures and separation of teeth from the gums, as well as other conditions that often require considerable cosmetic and functional corrective surgery (Brownson et al. 2016; Harrison and Hicklin 2016; Rogér et al. 2016; Brooks et al. 2017). However, because use of e-cigarettes is so new, there are uncertainties about the impacts of long-term use on oral health and general health.

As use of these new products has increased, conventional cigarette smoking has decreased, largely because of considerable effort in tobacco prevention and cessation public health initiatives during the past 40 years. In 2018, 13.7% of adults smoked cigarettes, the lowest rate since monitoring began in 1965 (Creamer et al. 2019). Nonetheless, cigarette smoking remains the leading preventable cause of disease (including oral diseases), disability, and death in the United States (U.S. Department of Health and Human Services 2014; Tomar et al. 2019). For example, the number of cigarettes smoked per day is tied to an increased risk for cancer of the oral cavity and pharynx (Figure 8).

Figure 8

Cigarette use and risk for developing oral cavity and pharynx cancer. Notes: Odds ratios with 95% Confidence Intervals presented. Prediction estimates for tobacco smoking were obtained using cubic regression spline models. The reference category was defined (more...)

Cigarette smoking contributes to the burden of periodontal diseases. A recent systematic review and meta-analysis of 12 prospective studies reported that smokers had an 85% higher risk for periodontitis than nonsmokers (Leite et al. 2018). Smoking is associated with poor periodontal treatment outcomes and implant survival rates (Warnakulasuriya et al. 2010). Quitting is associated with improved periodontal disease outcomes (Preshaw et al. 2005; Heasman et al. 2006; Leite et al. 2018). Relatively fewer studies have shown an association between smoking and dental caries (Vellappally et al. 2007; Benedetti et al. 2013) or tooth loss (Warnakulasuriya et al. 2010). Additional information on tobacco use including use of e-cigarettes is discussed in Section 5.

Cannabis Use

Cannabis describes the different products that come from the cannabis plant. They include marijuana and hemp, both of which contain cannabinoids, a group of active chemical compounds, such as tetrahydrocannabinol. Cannabis products are used for a wide range of putative medicinal effects, as well as a euphoric “high.” Increasing public acceptance of medical marijuana and the relaxation of state marijuana laws has left the public, health care providers, and legislators with multiple unanswered questions about the safety of the products derived from this plant and its effectiveness for therapeutic purposes.

High-quality studies examining the effects of cannabis use on oral health are lacking. Because of its classification as a Schedule 1 drug, there are restrictions on federal research with marijuana that contribute to the paucity of data on this topic. Legislation has been proposed to loosen these research restrictions (U.S. Department of Justice 2019). What is known about the oral implications of cannabis products is summarized in Table 3. Numerous case reports have linked smoked cannabis to oral cancer, and there also is evidence of a possible link between smoked cannabis, HPV infection, and OPC. However, large population-based studies and a comprehensive review conducted by the National Academies of Sciences concluded that cannabis use has not been associated with oral, head, or neck cancers (Rosenblatt et al. 2004; National Academies of Sciences, Engineering, and Medicine 2017), nor with HPV infection (Ortiz et al. 2018).

Table 3

Oral implications of cannabis products.

Darling and Arendorf (1993) found three significant oral conditions more frequently in adults who smoked cannabis and tobacco or used methaqualone (which is no longer legally manufactured) than in those who only smoked cigarettes or in nonsmoking controls.

These conditions were leukoedema (a filmy, opalescentto-whitish gray, wrinkled buccal epithelium), xerostomia (dry mouth), and traumatic oral ulcers. In a 2009 study, cannabis users 18 to 25 years of age had significantly more decayed surfaces, consumed more sugar-containing drinks, and had significantly fewer daily tooth brushings and dental visits than tobacco users (Schulz-Katterbach et al. 2009). In addition, some data support a positive association between cannabis use and periodontitis prevalence and severity, with deeper pockets and more clinical attachment loss (which signifies more severe disease) in people who used cannabis more frequently (Shariff et al. 2017; Chisini et al. 2019). Cannabis studies often have involved participants who also smoke cigarettes and/or use alcohol or other drugs, making it difficult to control for confounding variables (Darling et al. 1990; D’Amore et al. 2011). Additional information on marijuana use is provided in Section 5.

Methamphetamines

Methamphetamine (meth) is a highly addictive stimulant that has been used as a recreational drug since the 1990s and can have a significant impact on OHRQoL among adults (Mukherjee et al. 2018). Methamphetamine is ingested by smoking, nasal inhaling, or through intravenous injection. In a 2018 survey, it was found that 0.7% of the U.S. population 18 to 25 years of age and 0.8% of those 26 years or older reported having used methamphetamine during the past year (Substance Abuse and Mental Health Services Administration 2019).

The use of methamphetamine has a significantly negative impact on oral health. This impact is demonstrated by a rampant dental disease that is characterized as “meth mouth” (Clague et al. 2017). Methamphetamine users report pain and discomfort. Their teeth are decayed, broken, loose, and often heavily worn down. The maxillary anterior teeth are most affected by rampant tooth decay, especially in users who inject the drug (Shetty et al. 2016). Methamphetamine users also have more missing and untreated decayed teeth than age- and sex-matched non-users (Shetty et al. 2010; Shetty et al. 2016). Methamphetamine-induced bruxism (tooth grinding) results in loss of tooth structure through tooth wear, as well as tooth and restoration fracture. Tooth grinding also leads to TMD, particularly in female methamphetamine users (Donaldson and Goodchild 2006). Additional information on methamphetamine use is provided in Section 5.

Alcohol

Globally, alcohol use was ranked as the seventh leading risk factor for premature death and disability in 2016. A known cancer-causing agent and contributing cause of injury, alcohol is also an important contributor to oral cancers, periodontal disease, tooth loss, and other oral health conditions (Rehm et al. 2017; World Health Organization 2020).

Excessive alcohol use, in the form of binge drinking (five or more drinks per occasion for men, or four or more for women) and heavy drinking (15 or more drinks per week for men and 8 or more for women), is associated with an increased risk for many health problems, including oral diseases and facial injuries. Males 18 to 35 years of age often are seen in hospital emergency departments or oral and maxillofacial surgery departments with alcohol-related injuries sustained during an assault or a fall. Heavy alcohol consumption also has been associated with tooth loss in men (Copeland et al. 2004). Oral hygiene and periodontal conditions tend to be worse in people with alcohol use disorder, likely also because of poor dental care, accidents, and violence-related injuries.

The cancer-causing effects of alcohol extend to head and neck cancers (Hashibe et al. 2007), including cancers of the oral cavity, as well as pharyngeal, laryngeal, and esophageal cancers, especially when alcohol is used with tobacco (Bagnardi et al. 2001; Tramacere et al. 2010). The risks related to alcohol consumption begin at less than one drink per day and increase with heavy drinking or tobacco use (Scully and Bagan 2009). In the United States, these cancers account for the majority of alcohol-related deaths among men (Nelson et al. 2013). Other related issues include light drinkers, who were 1.17 times more likely to develop oral cancer and 1.23 times more likely to develop pharyngeal cancer, compared to non-drinkers or occasional drinkers. Cancer risk for heavy drinkers was 4.64 and 6.62, respectively (Tramacere et al. 2010). The Lancet recently published a study on global alcohol use and burden that found unequivocally that “alcohol use is a leading risk factor for [the] global disease burden and causes substantial health loss” (GBD 2016 Alcohol Collaborators 2018). The study also noted that for populations 50 years of age and older, cancers accounted for a large proportion of total alcohol-attributable deaths in 2016, constituting 27.1% of total alcohol-attributable female deaths and 18.9% of alcohol-attributable male deaths. Alcohol is considered a cause of squamous cell carcinomas in the head, neck, and esophagus, as well as subsites within the head and neck, including lip, oral cavity, pharynx, and nasopharynx. The study demonstrated that any level of alcohol consumption, even one drink per day, increases the relative risk of developing each of these cancers (GBD 2016 Alcohol Collaborators 2018).

In addition, alcohol use affects the prevalence of periodontal disease. Clinical attachment loss, a measure of periodontal disease, has been found to have a significant relationship with the number of drinks consumed per week (Tezal et al. 2004). Plausible explanations include alcohol’s effects on host defense, clotting mechanisms, bone metabolism, healing (e.g., protein deficiency), and direct toxic effects on periodontal tissues. Despite strong evidence to the contrary, a longitudinal study of dental health in a Swedish population sample (Jansson 2008) found no association between alcohol consumption and periodontal disease. Additional information on alcohol use is provided in Section 5.

Dietary Behaviors

Sugar-sweetened beverages (SSBs)—drinks with added sugars, including carbonated, fruit, sports and energy drinks (Park et al. 2016)—are the most common sources of dietary sugars in adults (Kim et al. 2017). In addition to the general deleterious health effects of added dietary sugar, such as increasing the risk for diabetes and cardiac disease, oral effects are known (World Health Organization 2003; Bernabé et al. 2014). Bernabé and colleagues (2014) reported a significant positive association between intake of SSBs and caries in adults and their findings were further supported by the results of a meta-analysis (Moynihan and Kelly 2014). Furthermore, Bernabé and colleagues (2014) reported that the number of SSBs adults drink per day is positively associated with the number of decayed, missing, and filled teeth (DMFT). They found that adults (30 years of age or older) who drink 1 to 2 and 3 or more SSBs daily had, respectively, 31% and 33% more DMFT than those who did not drink SSBs.

Tooth decay is a known precursor to tooth loss, and tooth loss is positively associated with intake of SSBs (Zhu and Hollis 2014; Kim et al. 2017). Young adults who drink SSBs one to two times a day have twice as great a risk of losing six or more teeth (OR 2.2) than those who do not drink SSBs. The risk is even greater for those who drink SSBs more than twice a day (OR 2.8) (Kim et al. 2017).

Menstrual Cycle

During the menstrual cycle, women experience hormonal fluctuations that influence the periodontium, which are specialized tissues (including the gums) that surround and support the teeth (Markou et al. 2009). These fluctuations, mainly in estrogen and progesterone, cause changes in the gingival and periodontal tissues (Machtei et al. 2004; Becerik et al. 2010; Shourie et al. 2012). Different phases of the menstrual cycle do not appear to correlate with the condition of the gingiva in orally healthy women. However, a significant exacerbation of pre-existing gingivitis during menstruation has been observed (Markou et al. 2009). Similarly, although ovarian hormones have just a slight effect on clinically healthy periodontium (Becerik et al. 2010), they may worsen pre-existing inflammation in gingival tissues (Shourie et al. 2012). These effects usually occur a day or two before menstruation starts and clear up shortly after (Markou et al. 2009).

Hormonal changes during the menstrual cycle cause some women to experience oral changes that may include redness of gums, bleeding gums, swollen gums, swollen salivary glands, and canker sores. These hormones affect blood supply to the gum tissue and the body’s response to toxins from plaque buildup. Sex hormones also increase the rate of folate metabolism in the oral mucosa. Because folate is necessary for tissue maintenance, increased metabolism may diminish folate stores and prevent tissue repair (Markou et al. 2009).

Oral Contraceptives

Oral contraceptives are one of the most widely used prescription medications in the United States, with about 11 million users (DeRossi and Hersh 2002). Oral contraceptives contain varying levels of progesterone and estrogen and mimic a state of pregnancy to prevent ovulation (Mascarenhas et al. 2003). Research suggests that prolonged use of contraceptives may detrimentally affect the periodontium (Saini et al. 2010) and increase risk for periodontitis (Kessler 2017).

There are several factors that could cause this. Changes in women’s hormone levels, as discussed above, have systemic influences that affect the gums. For example, higher levels of progesterone increase blood flow to the gum tissue, causing gums to be more sensitive and vulnerable to irritation and swelling. Changes in progesterone and estrogen levels affect collagen production in the gingiva, reducing the body’s ability to repair and maintain gingival tissues (Ali et al. 2016).

Furthermore, oral and other hormonal contraceptive users experience changes in saliva composition and decreased saliva production, which can lead to oral health problems, ranging from irritated gingiva to aggressive periodontitis. Contraceptives can increase inflammation and the quantity of gingival fluids, which increase the prevalence of healing complications (dry socket conditions) after tooth extractions. Thus, tooth extractions should take place on days 23–28 of the menstrual cycle (Kessler 2017). Finally, women using oral contraceptives have a higher prevalence of Streptococci mutans, the primary organism responsible for dental caries, in their oral cavities and consequently experience a higher incidence of dental decay (Ali et al. 2016).

Hormones and Aging

As women age, their estrogen levels fall, with consequences across body systems, including the oral-craniofacial complex. Menopause is defined as 12 consecutive months without a menstrual cycle. Perimenopause is the period around menopause in which hormone levels fluctuate. Hypoestrogenism, or a reduction in estrogen, can lead to decreased saliva production in postmenopausal women (Chaveli et al. 2011). Falling estrogen levels also can affect the oral mucosa, resulting in oral health problems that may include burning mouth syndrome, xerostomia (dry mouth), atrophic gingivitis (inflammation and swelling of the gums), periodontitis, and dysesthesia (Friedlander 2002; Cao et al. 2007). Xerostomia is a common symptom in menopausal women (Minicucci et al. 2013).

Menopause is a leading cause of osteoporosis (Becker 2006), which can affect the jawbone and reduce bone mineral density (BMD), contributing to periodontal disease progression. One study found that postmenopausal women had a higher prevalence and severity of periodontal disease (Yalcin et al. 2006).

Several studies have investigated the effect of hormone replacement therapy on oral health among perimenopausal and postmenopausal women. The results have been mixed, with some studies indicating improvements in dental pain, tooth mobility, depth of periodontal pockets (Lopez-Marcos et al. 2005), and tooth retention (Taguchi et al. 2004). However, a systematic review reported that hormone replacement therapy has no effect on the oral health of women (Meurman et al. 2009).

Pregnancy and Oral Health

Oral health is critical for pregnant women. During pregnancy, women may experience tooth decay, gingivitis, periodontitis, tooth loss, and erosive tooth wear.

Numerous studies have revealed that as levels of pregnancy-related hormones rise, the chances of gingivitis and periodontal disease increase in expectant mothers (Wu et al. 2015). As pregnancy progresses, levels of estrogen and progesterone produced in the ovaries and placenta rise. By the third trimester, these hormones peak and may induce immune responses that boost bacteria and inflammation, causing gingivitis and periodontal disease (Centers for Disease Control and Prevention 2019b).

Poor oral health during pregnancy has been linked to adverse health outcomes. For example, studies have shown that maternal periodontal disease is associated with increased risk for preeclampsia (Boggess et al. 2003), as well as preterm birth (Offenbacher et al. 2006; Corbella et al. 2016) and low birth weight (Gomes-Filho et al. 2016). Other factors, such as blood glucose levels, also affect these relationships. In addition, pregnant women are at higher risk of tooth decay because of factors that include an increase of acid in the oral cavity, dietary cravings for sugar, and limited attention to oral health care. Periodontitis in pregnant women is associated with a significantly increased risk for gestational diabetes, compared with women without periodontitis (Abariga and Whitcomb 2016). Experts recognize the importance of good oral hygiene and professional oral health care to reduce complications during pregnancy and at birth (Niessen et al. 2013).

Dental treatment during pregnancy may include dental examinations, radiographs, dental prophylaxis, local anesthetics, restorative care, and, if necessary, dental surgery (Silk et al. 2008). Because of possible patient discomfort, especially late in pregnancy, elective treatment is sometimes postponed until after delivery. Additional counseling by oral health providers should include instructions regarding proper oral hygiene, use of fluoride toothpaste, and dietary education about the adequate quality and quantity of nutrients for the mother-to-be and the unborn child. Providing timely educational information and preventive therapies to pregnant women also has been shown to reduce risk for dental caries in their children (Lucey 2009; Meyer et al. 2010).

Despite the importance of having good oral health during pregnancy, even with proper referrals, pregnant women often do not seek or receive dental treatment when it is needed, and those who do may face dentists who are hesitant or unwilling to provide care (Huebner et al. 2009). Rocha and colleagues (2018) conducted a systematic review of the use of dental services during pregnancy and reported that the prevalence of dental visits during pregnancy ranged from 33–68% in the United States and Canada. The authors also found that income, education, and race/ethnicity were significantly associated with visiting the dentist. Those with lower income and education and ethnic minorities were less likely to visit the dentist. Lee and colleagues (2021) obtained similar findings in a study in 31 states and New York city using cross-sectional data from the Pregnancy Risk Assessment Monitoring System (2012–2015), which collects information on the use of dental services (Stephens et al. 2020). They found that 19.7% of respondents reported having a dental problem during pregnancy, and 51.7% had at least one dental visit while pregnant. Non-Hispanic Black and Hispanic women were less likely to visit a dentist during pregnancy compared to non-Hispanic White women. In a study of the Virginia Pregnancy Risk Assessment Monitoring System 2012–2014 data (Naavaal et al. 2019), only 47% of women reported having a dental visit. Having dental insurance, knowledge of the importance of dental care during pregnancy, and counseling by a health provider were significant predictors of dental service utilization during pregnancy.

A study in California (Marchi et al. 2010) investigated use of dental services during pregnancy using data from the Maternal Infant Health Assessment, an annual population-based survey of mothers delivering live infants in California during February through May of each year. Only one-third of the women reported receiving any dental care during pregnancy, and 62% of those who reported dental problems did not receive care. As with other studies, this study found that ethnic minorities, low income, and less-educated women were at greater risk of not receiving dental care.

Atherosclerotic Cardiovascular Disease

Periodontal disease is associated with atherosclerotic cardiovascular disease, including coronary heart disease, cerebrovascular disease, and peripheral arterial disease, although the risks are not the same for all age groups. These associations are currently thought to operate indirectly through systemic inflammatory pathways that can facilitate a series of cascading events causing vascular damage, or more directly via pathogenic exposure (Figure 11).

Figure 11

Relationship of periodontal disease (PD) to cardiovascular diseases (CVD).

It is unclear if treating periodontal disease can prevent the onset of cardiovascular disease or secondary events. A 2017 systematic review found no studies on the topic (Li et al. 2017). However, when patients received nonsurgical periodontal treatment versus no treatment, there was a significant decrease in their C-reactive protein and leukocyte levels, which are blood serum markers for inflammation. In addition, periodontal treatment had a beneficial effect on some biochemical measures, such as blood lipid levels that can affect cardiovascular risk (Buhlin et al. 2009). Furthermore, a recent systematic review indicates that periodontitis may be a modifiable risk factor for cardiovascular disease (Sanz et al. 2020). These authors state that “severe periodontitis is independently and significantly associated with all-cause and cardiovascular mortality in several different populations.” On the other hand, a Cochrane review found that there is presently little substantive evidence that treatment for periodontitis can prevent or improve cardiovascular disease (Liu et al. 2019).

Cerebrovascular Accident and Transient Ischemic Attack

It has been suggested that certain types of inflammation, including periodontal disease, could be risk factors for stroke (Syrjanen et al. 1986). Periodontal disease is considered an independent risk factor for cerebral ischemia in men and younger individuals (Grau et al. 2004; Fagundes et al. 2019; Lee et al. 2019). People with severe periodontitis had a 4.3 times higher risk of cerebral ischemia than those with mild or no periodontitis (Grau et al. 2004). Severe periodontitis was found to be a risk factor in men but not women, and in adults younger than 60 years of age, but not for older people. One recent study has reported that gender and age (40–59 years) may be an effect modifier between severe periodontal disease and incident myocardial infarctions (Cho et al. 2021).

Diabetes and Glycemic Control

Diabetes is an important risk factor for periodontitis, and the prevalence of periodontitis is three times higher in individuals with diabetes than in those without diabetes (Preshaw et al. 2005). Conversely, moderate to severe periodontitis is a predictor for the development of type 2 diabetes (Demmer et al. 2008; Winning et al. 2017). Figure 12 shows a potential link between the two diseases.

Figure 12

Pathway showing link between periodontal disease and diabetes.

Systematic reviews of randomized controlled trials (RCT) on periodontal therapy and glycemic control in people with diabetes have been conflicting. A 2015 systematic review by Mauri-Obradors and colleagues (2015) of 21 RCTs on periodontal therapy and diabetic glycemic control concluded that the research literature does not support periodontal treatment as a means to improve serum glycated hemoglobin (HbA1c) levels in patients with type 1 diabetes. Conversely, a 2017 systematic review by Madianos and Koromantzos (2018), containing seven RCTs regarding periodontal therapy and diabetic glycemic control, concluded there was a statistically significant reduction in HbA1C levels at 3 and 6 months post-treatment. Most systematic reviews have reported some additional glycemic benefit when adjunctive antibiotics were used with periodontal therapy (Grellmann et al. 2016; Teshome and Yitayeh 2016; Souto et al. 2018). However, more consistent homogenous studies are needed because conflicting reports exist (Salvi et al. 2008; Lira Junior et al. 2017). Additional research to resolve inconsistencies in prior reports would be useful. People with diabetes are more likely to have periodontal disease, and treatment is extremely important.

Osteopenia and Osteoporosis

Osteopenia and osteoporosis are characterized by decreased BMD and bone microarchitecture, increasing the risk of bone fracture. An estimated 50% of the population in the United States aged 50 years and older will suffer from decreased BMD in their lifetimes (Wright et al. 2014). Low BMD in females (50%) is more prevalent than in males (20%) (Cosman et al. 2014). Non-Hispanic White and Hispanic populations have a higher prevalence of low BMD than do African Americans (Wright et al. 2014).

The impact of low BMDs on tooth loss and of periodontal disease on bone loss continues to be of interest. Although association between low BMD and periodontal disease has been shown (Iwasaki et al. 2013; Gil-Montoya et al. 2020), it is not clear what effect osteopenia and/or osteoporosis may have on periodontal disease. Among postmenopausal women, chronic periodontitis is more prevalent and severe in those with osteoporosis than in those with normal bone density (Wang and McCauley 2016). Normal levels of vitamin D and medication to treat osteoporosis may improve the periodontal status of these women (Penoni et al. 2017). In a systematic review and meta-analysis, Penoni and colleagues (2017) found that postmenopausal women with low BMD had greater clinical attachment loss—a sign of irreversible periodontal disease—than those with normal BMD. One study in Japan indicated that mandibular cortical width and extent of erosion seen on panoramic radiographs was significantly correlated with BMD, as measured using ultrasound densitometry, and held the potential for predicting osteoporosis risk (Ohtsuki et al. 2017). However, additional work is needed to verify this finding, establish the mechanism by which osteoporosis contributes to periodontal disease, and determine if advanced densitometry devices could be used to screen for osteopenia/osteoporosis.

Sickle Cell Disease

Sickle cell disease (SCD) is the most common inherited hematological disease in the United States. Though the actual prevalence of SCD is unknown, it is thought that sickle cell anemia or Hemoglobin SS (the most severe form), is the most prevalent form of the disease, occurring most frequently in African Americans and increasingly found in Hispanics (Hassell 2010). Other forms of SCD found in the United States include hemoglobin SC disease and hemoglobin Sβ thalassemia.

Certain dental conditions that are seen more often in people with SCD than in the general population include dental caries, orofacial or dental pain usually of undetermined origin, pulpal necrosis (death of dental pulp cells), periapical (at the root of the tooth) infections, osteomyelitis of the mandible (jaw bone infection), neuropathy (nerve pain), medullary hyperplasia with abnormal trabeculae spacing in the mandible and maxilla (abnormal bone and tissue growth in the jaw), and hypomineralization of the teeth (discoloration of tooth enamel) (Demirbas Kaya et al. 2004; Laurence et al. 2006; da Fonseca et al. 2007; Mulimani et al. 2016).

In medullary hyperplasia, the hyperplasia and compensatory expansion of the facial bones can result in changes in craniofacial bone structure, increasing the likelihood of dental malocclusion (Costa et al. 2015). Although there is little evidence of a causal pathway leading to dental caries, people with SCD may experience more dental caries and poor oral health because they prioritize other aspects of health care (Laurence et al. 2006; Laurence et al. 2013). Moreover, dental clinicians may be reluctant to treat people with SCD because they do not know how to address the potential complications (Passos et al. 2012). African Americans with SCD are more likely to be unemployed and less likely to have dental insurance (Laurence et al. 2006). These inequities, including the potential reluctance of dental providers to provide care, a low priority placed on oral health among patients with SCD, and the high cost of dental treatment may all be factors that contribute to the higher prevalence of dental caries in patients with SCD.

Cancer Treatment

The oral cavity can be at risk for a range of toxicities from cancer treatment, principally involving the mucosa (oral mucositis) and, to a lesser extent, in order of prevalence, salivary glands, bone forming the mandible or maxilla, and periradicular sites (National Cancer Institute 2020c). The various effects of cancer treatments on oral health are shown in Table 5. Unlike high-dose head and neck radiation, which causes irreversible damage to oral tissues, the long-term impact of high-dose chemotherapy on teeth and surrounding periodontium (Raber-Durlacher et al. 2004) or salivary glands (Wolff et al. 2017) is limited. The principal oral toxicity associated with high-dose chemotherapy is oral mucosal injury, called oral mucositis (Peterson et al. 2012). Oral mucositis can be extremely painful and debilitating. It often appears as red, burn-like sores or as ulcer-like sores ranging in size from 0.5 centimeters (cm) to 4 cm (National Cancer Institute 2020c).

Table 5

Prevalence of oral complications from cancer treatments.

Medications and Oral Health Complications

Sleep Apnea

People of all ages can have sleep apnea. It is normal to stop breathing for a few seconds during sleep, but it can be detrimental to health if it occurs too frequently (more than once per hour in children and 5–10 times per hour in adults) and lasts more than 10 seconds. Sleep apnea is a combination of apnea (cessation of breathing), hypopnea (reduction of breathing strength), and hypoxia (reduction in oxygen to the brain). Sleep apnea occurs in about 2–4% of the general population. With increasing age and obesity, the prevalence increases to 15% and 40%, respectively, depending on gender. Males are more at risk, and premenopausal females appear to be protected (Peppard et al. 2013; Heinzer et al. 2015).

Cessation of breathing during sleep can be caused by obstruction of the upper airway (big tonsils, large tongue, fat in throat and tongue [because of obesity], and small and narrow jaws) or it can be central, attributable to brain or lung altered reactivity or a weaker reflex to reopen the airway. Supine sleep position, alcohol use, and medications for anxiety (benzodiazepines) or pain (opioids) can also contribute to worsening the condition in some vulnerable people.

Sleep apnea can cause altered concentration and memory, as well as lower vigilance and attention. In adult women, fatigue is a dominant complaint and men complain of sleepiness. Sleep apnea is often associated with other health conditions, such as insomnia, snoring, high blood pressure, diabetes, headache, tooth grinding, low libido, and depression. These are not always the direct cause of sleep apnea; however, the coexistence of apnea can be an important aggravating factor. For example, having obstructive sleep apnea can increase an individual’s risk for hypertension.

Oral health professionals can screen patients for sleep apnea; however, formal diagnosis and assessment of its risk on function and health are the responsibility of a sleep physician who may order a sleep test with a device to measure sleep breathing activity (Kapur et al. 2017; Veasey and Rosen 2019). Only sleep physicians can diagnose and assess sleep breathing. They may then provide a continuous positive airway pressure (CPAP) device or refer the patient to a dentist who can provide an oral appliance. Some dentists work collaboratively with primary care physicians and sleep specialists as part of multidisciplinary care teams.

The first choice of treatment is a CPAP machine, which is prescribed by a physician. A CPAP machine reduces the health risks when it is used on a regular basis during sleep. The second choice is a mandibular advancement dental device or appliance that prevents backward movement of the jaw to prevent the upper airway closure. This device has been available for more than 30 years and its efficacy is proven (Marklund et al. 2019; Uniken Venema et al. 2020), although it may not work for everyone (Remmers et al. 2017; Sutherland et al. 2017). Dentists who have had special training and are qualified through the American Academy of Dental Sleep Medicine (American Academy of Dental Sleep Medicine 2021) are trained to provide these appliances (Gauthier et al. 2012; Haviv et al. 2014; Levine et al. 2018).

Based on recent evidence, both treatments have a similar effect. However, currently available data suggest that the mandibular advancement device is less effective in reducing apnea frequency and must be used for more hours per night and for more nights per week than the CPAP to achieve the same health benefit (reduction of morbidity/presence of disease or disorder and mortality) over time (Anandam et al. 2013; de Vries et al. 2018; Schwartz et al. 2018; Sutherland and Cistulli 2019). To reach the best efficacy with CPAP or dental devices, risk factors should be addressed by offering advice on how to improve sleep quality, lose weight, correct supine sleep position, initiate oropharyngeal exercise programs to increase muscle tone during sleep, and reduce alcohol use (Hsu et al. 2020; Lavigne et al. 2020).

Dentists also can provide orthodontic treatment or jaw surgeries to correct a narrow lower and upper jaw to prevent sleep apnea (Lin et al. 2020). Physicians can remove large tonsils and nasal obstructions, perform bariatric surgery, or stimulate nerves to push the tongue forward. Sleep apnea treatment has a better likelihood of succeeding by using a multidisciplinary team care approach that includes physicians, dentists, psychologists, speech therapists, and sleep specialists (Lavigne et al. 2020).

Management of Dental Caries

Modern management of dental caries emphasizes prevention, with personalized risk assessment, a preventive care plan, and disease management based on early detection. Although caries risk assessment has proven useful with children, its use in adults continues to be problematic. This is an important issue for facilitating patient-centered care, given that a person’s prognosis is dependent on a robust caries risk prediction modelling (Fontana et al. 2020). This work remains underdeveloped.

With greater attention to earlier detection and intervention, noninvasive or nonsurgical management of dental caries that preserves tooth structure is becoming more frequently utilized in adults (Slayton et al. 2016). These approaches are designed to arrest the caries process and allow remineralization of the carious lesion. Topical fluorides for adults, such as fluoride varnish, remineralize the tooth structure and prevent the caries process. SDF, mentioned above, also can be used in adults to arrest the caries process. A systematic review examined the use of SDF in adults with exposed root surfaces and found SDF to be effective in arresting the caries process on root surfaces of teeth (Oliveira et al. 2018). For dental caries in which minimal structure has been destroyed, minimally invasive restorative treatment can be provided with a goal of preserving as much tooth structure as possible to attain better long-term results. For teeth more severely affected by the caries process, restorative procedures, such as restorations (fillings) or crowns may be needed.

Management of Periodontal Disease

Periodontal disease prevalence increases with age and the incidence rises steeply in adults aged 30 to 40 years. It is estimated that the burden of periodontitis will continue to increase globally as working-age adults and older adults continue to retain more of their natural dentition (Tonetti et al. 2017). As the relationships between oral infection/oral inflammation and the risk for noncommunicable diseases—primarily cardiovascular diseases, diabetes, respiratory diseases and cognitive impairment—continue to be identified (Liccardo et al. 2019), the need to prevent and/or eliminate or reduce the adverse effects of severe periodontitis assumes greater significance.

Prevention of periodontal disease, similar to dental caries, requires an understanding of risk factors and the tailoring of prevention programs to individual needs through diagnosis and risk assessment. A new Periodontal Classification system (Caton et al. 2018a) identifies the stage of the disease based on severity and complexity of management and the grade of the disease that rates the risk of progression. These variables enable the clinician to identify the level of severity of periodontal disease, along with an individual’s comorbidities, thus enabling better targeting of preventive services. The removal of subgingival calculus remains a critical component to decrease inflammation and prevent and control periodontal disease. Adherence to recommendations about self-care is essential too, beginning with oral hygiene care to reduce plaque. Because periodontitis shares risk factors with other systemic diseases, such as heart disease and diabetes, WHO has strongly advocated for the use of the Common Risk Factor Approach to include self‐performed oral hygiene as part of healthy lifestyles (Tonetti et al. 2017).

The goal of periodontal treatment is to “control gingivitis and periodontitis, avoid disease progression leading to tooth loss, retain a functional dentition for a lifetime, preserve self‐esteem and improve quality of life” (Tonetti et al. 2017, p. 459). Adults need to be informed of the importance of seeking regular care if periodontitis is present. To achieve this goal, medical and dental health professionals need to be aware of the relationships between severe periodontitis and certain systemic diseases, and refer patients with a suspected problem for treatment. Adults with limited access to oral health care or limited funds to pay for care, however, may struggle to afford preventive measures or treatment of periodontal disease.

Management of Tooth Loss

Although adults have seen improvements in the number of teeth lost because of caries and periodontal disease, tooth loss in adults remains a problem today. Tooth loss can lead to such problems as poor diet, which can result in weight loss or weight gain, limited social contact, impeded speech, lowered self-esteem, or reduced employment opportunities (U.S. Department of Health and Human Services 2000). Adults missing their front teeth do not have the same employment opportunities as those with a complete smile. Chronic medical conditions, many of which begin in adulthood, can contribute to poor oral health. People with chronic conditions are more likely to have untreated dental disease, which can lead to tooth loss.

According to data from the 2011–2016 National Health and Nutrition Examination Survey, among adults older than 50 years of age who had a dental examination, the prevalence of edentulism (no teeth), severe tooth loss (less than eight teeth remaining), and lacking functional dentition (less than 20 teeth) were 10.8%, 16.9%, and 31.8%, respectively. In addition, those who reported select chronic conditions were significantly more likely to have severe tooth loss than were people without chronic conditions (Parker et al. 2020). The increase of tooth loss in adults with chronic conditions speaks to the importance of referrals between physicians and dentists to ensure that oral health problems are diagnosed and treated early to prevent tooth loss.

The replacement of missing teeth can be accomplished with a variety of dental procedures. Traditionally, a fixed bridge or a removable partial denture were the treatment options for missing teeth. With advancements in implant designs, surfaces, and treatment protocols during the past 20 years, implant success has improved; consequently, more adults are selecting implants as the treatment of choice to replace their missing teeth. In fact, data from the National Health and Nutrition Examination Survey shows that between 1999–2000 and 2015–2016, the largest relative increase in implant use occurred among adults aged 55 to 64 years (Elani et al. 2018). The costs of this tooth replacement choice, however, can be high, with estimates of replacing one tooth with an implant ranging from $3,000 to $6,000 (Alderman 2010; Healthline 2019).

With the increase in the use of implants, peri-implant disease has increased. The new classification system for peri-implant health and disease, including infections and other problems that may occur following the placement of implants, provides definitions for peri-implant health, peri-implant mucositis, and peri-implantitis. Evidence for the latter two suggest the role of bacterial plaque and plaque control measures as important in managing these conditions (Caton et al. 2018a).

Adults with Disabilities and Special Health Care Needs

Adults with disabilities represent a diverse population, with some having developmental or physical disabilities from birth, while others acquire disabilities as children or adults. Similarly, their living arrangements are as varied, with some living in the community, while others may require community homes or assisted living. Overall, the percentage of people with disabilities in the U.S. civilian population slightly increased from 12% in 2010 to about 13% in 2016. As the U.S. population ages, the percentage of people with disabilities will increase as well. In 2016, for adults aged 18 to 64 years, the rate of disability was estimated to be 11%, while in people 65 years of age and older the rate of disability was 35%. Among the population with disabilities, more than half (51%) were people aged 18 to 64 years, while 2 in 5 (41%) were aged 65 years and older. In 2016, 36% of people with disabilities aged 18 to 64 years, living in the community, were employed (Kraus et al. 2018).

Adults with special health care needs (SHCNs) often have underlying chronic conditions with associated risk factors, such as poor hygiene, dry mouth, increased inflammatory load, and poor systemic health. The combination of chronic conditions with SHCNs has a profound effect on oral health; although some people may lack the dexterity or cognitive ability to maintain oral hygiene, others may have to take medications that compromise their oral health. Systemic changes that accompany certain chronic conditions can interfere with oral health. The opposite also is true—poor oral health can have a lasting impact on general health and well-being. For example, non-functional dentition that results from dental disease or missing teeth could compromise an individual’s ability to eat, affecting their nutritional intake and overall health (Chavez et al. 2018). An adult with a spinal cord injury or multiple sclerosis may be more susceptible to oral diseases, such as periodontal disease and dental caries, because of the inability to perform daily oral care. Adults with disabilities and SHCNs also face enormous barriers in accessing dental care compared to their healthier counterparts (Glassman and Miller 2003).

Although children with SHCNs have public or private health insurance and hence, relatively better access to care as they transition to adulthood, a vast majority of them risk losing coverage once they become young adults (Fishman 2001).

Incarcerated Populations

Inmates have higher rates of substance abuse, psychological disorders, and chronic and communicable diseases than the general population. For example, rates of diabetes, chronic respiratory conditions, and liver disease are more than twice that of the general population (Trotter II et al. 2018). The incidence of prior substance abuse, pharmacologic treatment for psychiatric and chronic diseases, and effects of chronic disease all negatively affect oral health. Indeed, the prevalence of dental caries, periodontal disease, and other oral diseases is higher in inmates than in the general population (Treadwell and Formicola 2008). Violence in incarcerated environments frequently involves facial trauma, with mandibular and facial fractures being the most common injuries (Henning et al. 2015). Incarceration also engenders stress and anxiety that can lead to increased incidence of such habits as grinding the teeth (Cavallo et al. 2014). Access to appropriate dental and medical care while incarcerated is limited; the only articulated standard of care is that inmates should be merely “free from deliberate indifference to serious medical needs” (Makrides and Shulman 2017, p. S1). Although it is generally understood that inmate oral health status is poorer than that of the general U.S. population, there is insufficient data to guide oral health policy or clinical guidance for this population (Treadwell and Evans 2019).

Veterans

Most data regarding the oral health of veterans are derived from veterans eligible for dental care provision through the U.S. Department of Veterans Affairs (VA). The median age of veterans is 65 years for men and 51 years for women, making this an older population group (U.S. Department of Veterans Affairs 2019). Studies demonstrate that this group of veterans are more dentally and medically complex than the general population. In addition, VA medical centers have unique treatment centers, such as spinal cord injury centers, rehabilitation centers, or substance abuse centers. Patients receiving treatment for these chronic debilitating conditions are at high risk for oral diseases and may have worse oral health than the general population. An evaluation of veterans receiving services for the first time from VA Dentistry found that 13% were edentulous (toothless) and that 58% of dentate veterans required caries-related treatment. Veterans are more likely to have periodontitis or to have more teeth affected by dental caries, but military service appears to only be associated with an increase in dental restorations (Schindler et al. 2021). With a mean of 2.2 teeth per person treated for caries, this group had a higher caries level than the general U.S. population (Jurasic et al. 2019). VA Dentistry has emphasized preventive care and has shown that the increased use of fluoride for high caries risk patients has led to fewer restorations placed (Jurasic et al. 2014). More information on veterans is provided in Section 1.

Victims of Abuse

Interpersonal violence may be physical, sexual, or psychological and includes intimate partner violence, sexual assault, sex trafficking, child maltreatment, and family violence. More than 18 million women and more than 4 million men experience physical violence, rape, or stalking in the context of intimate relationships (Smith et al. 2018). Sexual violence reportedly impacts 1 in 3 women and 1 in 4 men during their lifetimes (Basile et al. 2014), and an estimated 20% of women and 2% of men have reported that they have been victims of sexual assault (rape or attempted rape) (Basile et al. 2014). It is hard to find reliable statistics related to human trafficking because of the hidden nature of the crime and challenges in identifying individual victims (U.S. Department of State 2021). In addition, little is known about the oral health of these individuals and the degree to which it increases the general burden of disease in this country.

In a study of 304 women seeking oral treatment in a community setting, the majority (67%) were found to have experienced some form of domestic psychological or physical violence (Kundu et al. 2014). These women reported that the abuse they experienced also affected their oral health practices and was linked to their oral health. Clearly, it is likely that an oral health professional will come into contact, knowingly or unknowingly, with a survivor of interpersonal violence. Dental professionals should remain committed to understanding these problems in order to identify and respond appropriately to them. Professional training on the indicators of human trafficking and the importance of using a survivor-centered, trauma-informed approach is recommended (Office on Trafficking in Persons 2020).

Some injuries may be visible to an oral health professional—oral and facial trauma, including injuries to the mouth, head, neck, jaw, teeth, and gums (Ellis et al. 2019). Other signs of abuse may include missing or chipped teeth, fractures, soft tissue injuries, and trauma in nerves to the mouth and jaw (Kundu et al. 2014; Mukherji 2015; Ellis et al. 2019). However, abuse may not always be apparent. Obvious signs of physical harm, and fearfulness and anxiety in the dental setting are potential signs of traumatic or abusive experiences.

Violence also can affect a victim’s ability to maintain oral health in terms of regular tooth brushing and preventive care. Oral health issues stemming from inadequate nutrition and proper dental care have also been identified among victims of violence (Fischer et al. 2017), as have infectious complications associated with HIV, other sexually transmitted diseases, and oral cancers (Mukherji 2015; Fischer et al. 2017).

Community-Based Interventions

Although many community-based oral health care programs have been developed for children, there is a paucity of similar community-based programs for working-age adults. The burden of unmet oral health needs on adults’ quality of life is substantial (Institute of Medicine 2011a; Benzian and Williams 2015), especially for racial/ethnic minorities and immigrants in underserved communities (Institute of Medicine and National Research Council 2011). Community-based interventions to prevent oral diseases and lower risk are needed for adults in group homes or assisted living facilities with chronic diseases that increase their risk for oral diseases.

Interprofessional Care

Interprofessional health care has been extensively discussed, particularly regarding preventive, diagnostic, and emergency procedures within medical care settings. To assist in the implementation of interprofessional dental care, the U.S. Department of Health and Human Services published a report, “Integration of Oral Health and Primary Care Practice,” which provided interprofessional oral health core clinical competencies for primary care providers. These primary care providers include nurse practitioners, nurse-midwives, medical doctors, doctors of osteopathic medicine, and physician assistants (Health Resources and Services Administration 2014). Subsequently, the National Academies of Sciences, Engineering, and Medicine evaluated active interprofessional programs. Most of those programs involved preventive care for children and elders and emergency care for specific adult groups, such as people with diabetes or pregnant women (Atchison et al. 2018). Although these programs currently are limited, efforts are being made to expand training and structures for physicians to carry out preventive dental treatments, as well as for dentists to carry out limited preventive primary care (Giddon et al. 2013).

Dental Caries

Although prevalence of caries slowly decreased from approximately 95% to 91% since the 2000 publication of Oral Health in America for working-age adults (20–64 years of age) (Figure 13), Americans continue to be challenged by the near-ubiquitous prevalence of lifetime tooth decay experience through adulthood, regardless of poverty status or race/ethnicity. This small decrease was driven by data for adults aged 20 to 34 years, a group who experienced a significant decrease in caries prevalence from 92% to 82% during the same time period. Dental caries experience represented a unique oral health paradox 20 years ago, in which health disparities between high- and low-income groups actually favored lower-income groups (96% vs. 86%) (Figure 14). Today, dental caries has increased for those living in poverty, while decreasing for those whose incomes were at least twice the federal poverty guideline (FPG) or higher; the result has been elimination of the health disparity between these groups of working-age adults.

Figure 13

Percentage of adults ages 20–64 with dental caries in permanent teeth by age group and gender: United States, 1988–1994, 1999–2004, 2011–2014. Note: Prevalence of dental caries in permanent teeth (DMFT > 0).

Figure 14

Percentage of adults ages 20–64 with dental caries in permanent teeth by age group and poverty status: United States, 1988–1994, 1999–2004, 2011–2014. Notes: Prevalance of dental caries in permanent teeth (DMFT > (more...)

Although the overall percentage of Americans experiencing dental caries has changed little in the past 20 years, the actual number of tooth surfaces affected by dental caries has substantially decreased. There are 128 tooth surfaces potentially at risk for dental caries among adults. Twenty years ago, working-age adults had a mean of 42 dental surfaces affected by caries. Now the mean is 28 dental surfaces (Figure 15). Overall, this decrease was experienced by all working-age adults, regardless of poverty status. However, the decrease was more pronounced for those living at 200% of the FPG or higher (41 vs. 26 affected surfaces) compared to those living in poverty (43 vs. 35 surfaces) (Figure 16). The decrease in mean number of dental surfaces affected by dental caries for all age groups during the past 20 years can generally be attributed to a decline in the number of tooth surfaces receiving dental treatment for caries. In other words, fewer surfaces are filled and fewer surfaces are lost because of tooth extractions.

Figure 15

Mean number of decayed (DS), missing (MS), or tilled surfaces (FS) of permanent teeth in adults ages 20–64 by gender and age group: United States, 1988–1994, 1999–2004, 2011–2014.

Figure 16

Mean number of decayed (DS), missing (MS), or filled surfaces (FS) of permanent teeth in adults ages 20–64 by poverty status and age group; United States, 1988–1994, 1999–2004, 2011–2014. Note: Federal Poverty Guideline (more...)

A greater challenge for working-age adults is untreated caries. Unlike the progress seen in younger children, there has been little change in untreated dental caries in working-age adults during the past 2 decades (28% vs. 29%) (Figure 17). More important, the disparities for untreated caries continue to be substantial. For example, more than half of working-age adults living in poverty have untreated caries (52%), whereas only 1 out of 5 adults with incomes of twice the FPG or higher have untreated caries (20%) (Figure 18). Twenty years ago, a typical working-age adult living in poverty had about four tooth surfaces affected by untreated caries, whereas a more affluent adult had only one tooth surface affected by untreated caries (Figure 19). Now, the mean number of surfaces affected by untreated caries has increased by 50% for working-age adults, regardless of poverty status.

Figure 17

Percentage of adults ages 20–64 with untreated dental caries in permanent teeth by age group and gender; United States, 1988–1994, 1999–2004, 2011–2014. Note: Prevalence of untreated dental caries in permanent teeth (DT (more...)

Figure 18

Percentage of adults ages 20–64 with untreated dental caries in permanent teeth by age group and poverty status: United States, 1983–1994, 1999–2004, 2011–2014. Notes: Prevalence of untreated dental caries in permanent (more...)

Figure 19

Mean number of dental surfaces affected by untreated dental caries in permanent teeth among adults ages 20–64 by gender, race/ethnicity, and poverty status: United States, 1988–1994, 1999–2004, 2011–2014. Notes: Federal (more...)

Periodontal Disease

Although the prevalence of periodontal disease in American adults seems to have remained consistent during the past 20 years, there have been important changes in how the disease is measured, monitored, and reported based on our evolving understanding of the etiology and natural history of the disease (Dye and Thornton-Evans 2007; Holtfreter et al. 2015). Consequently, there are new standards for periodontal disease case definitions for population-based surveillance activities (Eke et al. 2012) and new disease case definitions for individual classification purposes (Caton et al. 2018a; 2018b). Both of these initiatives have the potential to improve understanding of prevalence trends, effective preventive interventions, and better treatment modalities in the future. However, an important challenge remains—maintaining an effective surveillance system for periodontal disease.

It is estimated that the prevalence of periodontitis increased globally by more than 50% from 1990 to 2010 (Marcenes et al. 2013). Currently, 1 in 10 Americans aged 45 to 64 years has severe periodontitis, with men nearly three times more likely to have the disease than women (Eke et al. 2018). Severe periodontal disease affects 1 in 8 Mexican Americans, non-Hispanic Blacks, and those living in poverty. Because these individuals have reduced access to oral health care services (Seo et al. 2019), health disparities likely will continue to persist in these groups. More important, given that the prevalence of periodontitis increases with age, as demographic changes in the United States continue to shift towards more people living longer, periodontitis will continue to increase as an aging population retains more teeth.

Given the significance of this disease, it is an important public health problem that must be addressed (Tonetti et al. 2017). Nonetheless, there are virtually no public health programs for periodontal disease prevention and control (Janakiram and Dye 2020).

Smoking represents the greatest risk factor for developing severe periodontitis. Among adults aged 45 to 64 years, 1 in 4 current smokers has severe periodontitis, and nearly 75% of smokers have some form of periodontal disease (Eke et al. 2018). This suggests that ongoing efforts to reduce tobacco use have great potential to reduce the prevalence of periodontal disease in the United States. Although there have been substantial improvements in the past 20 years in our understanding of how periodontal disease is measured and progresses across a lifetime, prevention and control of periodontal disease has primarily been focused on the individual, using patient-focused approaches, such as smoking cessation interventions offered by health professionals (Janakiram and Dye 2020). Although individual approaches used for tobacco cessation activities do work, smoking quit rates remain low (3–5%) (Lancaster and Stead 2017).

Because periodontitis shares several risk factors, such as smoking, with other noncommunicable diseases, such as cardiovascular disease, the use of a Common Risk Factor Approach (CRFA) may have the greatest potential for preventing periodontal disease in populations. However, challenges in implementing a CRFA for periodontal disease need to be addressed before substantial reductions in the prevalence of periodontitis can be realized (Janakiram and Dye 2020). These challenges include the need to build the appropriate evidence to help inform guidelines for implementation and to strengthen reporting guidelines for periodontal disease surveillance, including the evaluation of interventions.

Overcoming some of these challenges will require new initiatives to communicate the adverse health impacts of periodontal disease and improve capacity to monitor effectiveness of prevention and control activities.

Tooth Loss

Tooth loss in adults has decreased significantly since the turn of the century, and this reflects important progress in improving oral health among working-age adults. The percentage of all working-age adults retaining a full dentition (28 teeth) increased from 31% to 47% during the past 20 years (Figure 20), reflecting an important trend that is likely to continue. This increase was substantially consistent across all age groups regardless of poverty status—except for adults aged 50 to 64 years, among whom was no change for those living in poverty (Figure 21). Those aged 20 to 34 years experienced the greatest increase in tooth retention, and this increase also was observed across race/ethnic and poverty subgroups.

Figure 20

Percentage of adults ages 20–64 with a complete permanent dentition by age group and gender: United States. 1988–1994, 1999–2004, 2011–2014. Note: Complete dentition is having all natural teeth remaining (total = 28), excluding (more...)

Figure 21

Percentage of adults ages 20–64 with a complete permanent dentition by age group and poverty status: United States. 1988–1994, 1999–2004, 2011–2014. Notes: Complete dentition is having all natural teeth remaining (total (more...)

The percentage of working-age adults with a functional dentition (having 21 or more natural teeth) increased from 80% to 91% in the past 20 years (Figure 22). Although all subgroups experienced substantial increases in functional dentition, non-Hispanic Whites and Mexican Americans remain more likely than non-Hispanic Blacks to have a functional dentition and those more affluent are also more likely to have a functional dentition, compared to those living in poverty (Figures 23-24). Those aged 50 to 64 years experienced the greatest increase in a functional dentition (80% vs. 60%) during the past 20 years. Although this increase also was observed across all major subgroups, health disparities for this oral health measure also were the greatest in this age group.

Figure 22

Percentage of adults ages 20–64 with a functional dentition by age group and gender: United States, 1988–1994, 1999–2004, 2011–2014. Note: Functional dentition is having 21 or more permanent teeth remaining, excluding third (more...)

Figure 23

Percentage of adults ages 20–64 with a functional dentition by age group and poverty status: United States, 1988–1994, 1999–2004, 2011–2014. Notes: Functional dentition is having 21 or more permanent teeth remaining, excluding (more...)

Figure 24

Percentage of adults ages 20–64 with a functional dentition by age group and race/ethnicity: United States, 1988–1994, 1999–2004, 2011–2014. Note: Functional dentition is having 21 or more permanent teeth remaining, excluding (more...)

Trends in edentulism (complete tooth loss) among working-age adults also have shown major improvement since 2000. Slade and colleagues (2014) examined 5 decades of population-based surveys on edentulism in people 15 years of age and older and found that the prevalence of edentulism in U.S. adults declined from 18.9% to 4.9%. The authors noted that the rapid decline is in large part a function of higher edentulism in birth cohorts born earlier than the 1930s, so that the rate of decline in edentulism has slowed with their passing. They also found that for the birth cohorts of 1954–1963 and 1965–1973, incidence rates were equivalent to about 1% per decade. However, socioeconomic disparities have become more pronounced, to the extent that “edentulism is now virtually unknown in the highest quartile of the income distribution” and “… is concentrated in low-income households located in states with a long history of poverty” (Slade et al. 2014).

This finding confirmed the results of Wu and colleagues (2012) from the National Health Interview Survey data. These researchers examined edentulism trends between 1999 and 2008 among adults aged 50 years and older in five racial/ethnic groups in the United States: Asians, African Americans, Hispanics, Native Americans, and non-Hispanic Whites. They found that in 2008, Native Americans had the highest predicted rate of edentulism (24%), followed by African Americans (19%), Whites (17%), Asians (14%), and Hispanics (14%). From 1999–2008, the survey identified an overall significant downward trend in self-reported edentulism.

However, this decline varied by ethnic group, with Native Americans experiencing a much slower rate of decline in edentulism during this period.

Orofacial Pain and Temporomandibular Disorders

The past 20 years have seen a continuing evolution in the diagnostic classification of temporomandibular disorders (TMD), including their differentiation from other orofacial pain problems. TMD is now widely recognized as a chronic pain condition, similar to other chronic pain problems in its psychosocial impact. The emphasis in treatment has shifted from invasive surgical approaches to more conservative and holistic options. Although trauma to the jaw or temporomandibular joint plays a role in some TMD, in most cases the exact cause of the disorder is not clear. Equally important, the range of symptoms can vary, and pain may not always be site specific. Because the exact causes and symptoms frequently are not clear, identifying these disorders can be difficult and confusing. There also is sometimes an underlying emotional or psychological component to the development and persistence of TMD. In fact, the presence of other painful conditions is a strong predictor of new cases of TMD (Von Korff et al. 1993; LeResche et al. 2007; Bair et al. 2013), as well as of higher levels of disability in people with TMD (John et al. 2003). The clinical importance of viewing TMD in the context of other pain problems is increasingly clear. See Section 5 for more information on oral pain and TMD disorders.

Because TMD pain often can be heterotopic—that is, the location of the pain and the source of the pain are not the same—TMD pain can present diagnostic challenges.

Without the correct diagnosis, successful management of TMD pain is unlikely. Furthermore, clinicians often under-recognize the wide variability in TMD’s impact on individuals, its association with psychosocial factors, or that it sometimes is associated with chronic pain and other conditions elsewhere in the body. For example, one study reported that orofacial pain was the only complaint during a heart attack in 6% of patients (Kreiner et al. 2007). Consequently, oral health providers frequently need to collaborate with other health care providers to help inform decision making that leads to better outcomes for adults experiencing TMD pain.

Evidence-based dental education can best address the challenges of diagnosing and managing this condition. Predoctoral teaching about the causes and treatment of TMD has progressed, but some schools do not address the topic adequately, and some others still are teaching outdated concepts. Standards are needed to ensure that all predoctoral dental students learn how to diagnose and treat nondental orofacial pain problems (Klasser and Greene 2007).

Oropharyngeal Cancer and Human Papillomavirus

Although the prognosis for cancer of the oral cavity and pharynx has gradually improved during the past 20 years (National Cancer Institute 2018), the prevalence of oropharyngeal squamous cell cancer (OPC) caused by the human papillomavirus (HPV) has increased dramatically during the past 25 years. HPV-associated oral cancers have doubled, with men having 3.5 times more OPCs than women (Figure 25) (Van Dyne et al. 2018). Seven out of ten OPCs in the United States are caused by HPV and the number of new cases is increasing each year (National Cancer Institute 2020d). The increasing incidence of HPV-OPC now has surpassed other HPV-associated cancers and become the most common of these cancers (Van Dyne et al. 2018), an increase that appears to be driven by generational changes in sexual behavior (D’Souza et al. 2014). Research suggests that oral sexual behavior explains some of the differences in oral HPV16 prevalence. The influence of other factors remains unknown.

Figure 25

Change in the number of HPV-associated cancers (oropharyngeal vs. all others): United States, 1999 and 2015.

Although many people are likely exposed to oncogenic oral HPV infection in their lifetimes, most do not develop HPV-related OPC. The reason that some individuals develop OPC, while most clear HPV infections without developing HPV-related OPC, is not well understood. Improvements in understanding the pathogenesis would offer potential for improving risk assessment and early detection. In areas where pathogenesis remains uncertain, innovative research methods are needed to leverage approaches other than the traditional randomized clinical trials to address these unanswered questions.

Another challenge is attributable to the limited ways available to help reduce HPV infection in adults. Preventive (prophylactic) HPV vaccination was first approved in 2006 for all females aged 9 to 26 years in the United States and expanded in 2009 for use in males aged 9 to 26 years for the prevention of genital warts caused by HPV 6 and 11. Although the Advisory Committee on Immunization Practices (ACIP) recommends HPV vaccination for preteens and adolescents, as well as for adults through 26 years of age, ACIP does not recommend vaccination for adults aged 27 to 45 years in most circumstances. The Gardasil^® 9 (Merck) vaccine, which was discussed in Chapter 1, is licensed for the prevention of oropharyngeal and other head and neck cancers. In addition, the vaccine prevents those anogenital cancers caused by the HPV types included in the vaccine. Consequently, in 2020 the U.S. Food and Drug Administration (FDA) approved the vaccine for the prevention of oropharyngeal and other head and neck cancers caused by HPV types 16, 18, 31, 33, 45, 52, and 58 for both males and females aged 9 through 45 years (U.S. Food and Drug Administration 2020). Additional information pertaining to the Gardasil^® 9 (Merck) vaccine and adolescents is provided in Section 2B. National health and survey data is showing that the prevalence of oral HPV16/18/6/11 infections is significantly lower in vaccinated versus unvaccinated individuals (0.11% vs. 1.61%; Padj = 0.008) (Chaturvedi et al. 2018). Although these data are promising, the impact of the vaccine on HPV-OPC will not be realized for at least 30 years, given that HPV-OPC is typically diagnosed in people in their forties and fifties.

Moreover, determining the best method to screen for HPV-related OPC remains a challenge, especially because these lesions often are difficult to diagnose in the earliest stage. A premalignant state for HPV-related OPC is not acknowledged by pathologists because premalignant lesions have not been observed (Lewis et al. 2018). In addition, there is a lack of validated biomarkers suitable for screening for HPV-related OPC. However, if acceptable biomarkers are identified, their benefit must be weighed against the potential harm of identifying individuals without detectable cancer for whom surveillance and risk are unclear (D’Souza et al. 2019).

Dental Fear and Anxiety

As noted in Chapter 1, 20% of U.S. adults experience moderate to high dental fear/anxiety, and an estimated 7% experience high fear/anxiety (White et al. 2017). These estimates are relatively unchanged from those documented since the 1950s (Smith and Heaton 2003). Even as dental care access and quality have increased, fear/anxiety has persisted in the United States while decreasing in other countries (Svensson et al. 2016).

Dental fear/anxiety strongly impacts utilization of dental care—even among those with access to care—predicting delayed appointment scheduling, canceled or missed appointments, and avoidance of necessary treatment (Armfield et al. 2007; Meng et al. 2007). A total of 5–10% of adults report delaying or avoiding necessary dental care because of fear/anxiety (Milgrom et al. 2010).

Greater fear/anxiety is associated with more decayed and missing teeth, and with fewer functional teeth (Schuller et al. 2003), as well as with dissatisfaction with one’s mouth, lower perceived quality of life, and poorer self-esteem (Locker 2003; Crofts-Barnes et al. 2010). Although onset during childhood is most frequent, dental fear/anxiety can develop at any age and typically remains stable across the lifespan (Locker et al. 1999; Thomson et al. 2009). Additional knowledge is needed to understand how dental fear develops and to identify effective approaches for preventing and managing dental fear and anxiety.

Tobacco Product Use

Since 2000, evidence has confirmed that tobacco use is a risk factor for OPC and potentially malignant oral disorders. Despite a reduction in tobacco use in the United States (Centers for Disease Control and Prevention 2018), the incidence of oral and pharyngeal cancers has steadily risen (Ellington et al. 2020). This change is attributed to an increase in OPCs, largely driven by oral HPV infection and its association with tongue and tonsillar cancers, for reasons not well understood, but probably unrelated to tobacco use (Tota et al. 2017). Yet, there has been a significant decrease in the incidence of some oral cavity cancers, notably on the floor of the mouth (Howlader et al. 2019), which is likely explained by the reduction in smoking.

Considerable effort has gone into, and success achieved in, curbing the cigarette smoking epidemic during the past 50+ years (U.S. Department of Health and Human Services 2020b). Adult cigarette smoking prevalence of 13.7% in 2018, represents the lowest recorded estimate and a 65% decline since monitoring began in 1965 (Creamer et al. 2019). Nonetheless, cigarette smoking remains the leading preventable cause of disease, including oral diseases, disability, and death in the United States (Warnakulasuriya et al. 2010; U.S. Department of Health and Human Services 2014; Tomar et al. 2019). However, encouraging oral health professionals to incorporate tobacco cessation programs into their practice is challenging. Little progress has been made in promoting tobacco cessation in the dental setting. Further identification of barriers and the development of strategies to overcome this problem are needed.

During the past 20 years, waterpipe tobacco, e-cigarettes, and spit-free (American snus and dissolvable tobacco) oral tobacco products have become available in the United States and collectively pose significant potential risks to oral health. Important disparities in tobacco use remain in the U.S., despite significant declines in overall cigarette smoking during the last 2 decades (U.S. Department of Health and Human Services 2020b). This has the potential to widen disparities in oral health over time, given the sociodemographic and geographic differences in the use of these tobacco products. The increased use of e-cigarettes is a significant concern and presents a new challenge that may impact oral health. Daily use of e-cigarettes has been associated with higher rates of tooth loss (Huilgol et al. 2019) and gingival disease in people who use them, compared to people who have never used a tobacco product (Vora and Chaffee 2019). However, because many e-cigarette users are current or former smokers, it is difficult to measure the singular impact of e-cigarettes on people who have used both combustible and e-cigarettes (Glasser et al. 2017).

Some recent studies have found that flavored e-cigarette aerosols are associated with a 27% decrease in the hardness of enamel in users (Kim et al. 2018). Oral mucosal lesions (Mokeem et al. 2019), nicotine stomatitis (inflammation), and oral hairy tongue (Bardellini et al. 2018) also have been reported among e-cigarette users. In a small study of men who had used e-cigarettes for an average of 2 years, researchers found no meaningful difference in periodontal disease (Javed et al. 2017). In contrast, cigarette smokers who quit smoking for 2 weeks and used e-cigarettes instead had more gingival inflammation and bleeding on probing during this period (Wadia et al. 2016).

Challenges in these studies, which would also apply to future studies, include the wide variability of e-cigarette products. More than 460 different brands of e-cigarettes are sold on the U.S. market, with more than 7,700 (Grana et al. 2014) combinations of flavors and constantly evolving product designs as well as inconsistent quality control (Trtchounian and Talbot 2011), differences in nicotine levels (Cobb et al. 2010; Pagano et al. 2015), and other factors create a challenge for researchers who are studying these products’ effects on oral health and general health (Williams and Talbot 2011). The recent increase in the use of waterpipe tobacco smoking and newer electronic nicotine delivery systems among young and working-age adults also suggests the need to further delineate their prevalence and risks for oral cancer, OPC, and other oral diseases.

Although there is considerable research regarding the carcinogenic effects of chewing, dip, and spit tobaccos (Boffetta et al. 2008), not as much is known about snus, a powdered smokeless tobacco that is infrequently used in the United States, but that may have serious oral health consequences (Patil et al. 2019).

Cannabis Use

Since the turn of the century, there has been limited research to advance the evidence base on cannabis use and oral health and disease. For example, the role of cannabis use in the development of dental caries is unclear, although there are some studies that show more caries among users (Schulz-Katterbach et al. 2009). Unanswered questions remain including whether cannabis affects motivation in ways that could impact engagement in recommended oral hygiene behaviors or seeking oral health care, whether its use leads to dry mouth or an increased appetite for sweet and salty foods and beverages, and whether these things, in combination, create a cariogenic environment. It is currently unknown whether some forms of cannabis pose greater risks for oral health, whether frequency of use or route of ingestion matter, and whether the effects of cannabis are different when used in combination with smoked tobacco, alcohol, or other drugs.

New challenges have emerged as more states legalize recreational and medicinal cannabis. Measuring the impact upon oral health of cannabis use must start with more high quality, reproducible research on this drug. Topics to be covered include the types used (smoked, vaporized, edibles, and other forms), the psychological and motivational impact of tetrahydrocannabinol on oral self-care, the concentration of different cannabinoids, and FDA-approved medications. Without that knowledge, clinicians, patients, and policymakers will make decisions based on limited and possibly anecdotal information. The challenge remains to incorporate information on cannabis use and oral health into the curriculum of dental, dental hygiene, and dental assisting programs.

Alcohol

Our knowledge of the effects of alcohol on oral health has increased dramatically during the past 20 years. Epidemiological research now links alcohol use to a variety of oral diseases (Bagnardi et al. 2001; Tramacere et al. 2010). Not only has this newer research replicated previous findings, it also has identified mechanisms that firmly establish alcohol use as a significant modifiable risk factor for oral cancer, periodontal disease, and dental caries.

Improved study designs and meta-analyses have provided a better understanding of the effects of alcohol on oral disease, interactions with tobacco and other factors, and mechanisms of action. Prior research focused mainly on the oral health consequences of chronic alcohol dependence and assumed that the increased prevalence of tooth loss and periodontal disease were a function of poor health habits, rather than the direct effect of alcohol (Tezal et al. 2004). More recent studies have identified the health consequences of different levels of alcohol exposure, providing stronger evidence for plausible causal mechanisms. As previously discussed, plausible causal mechanisms include alcohol’s effects on host defense, clotting mechanisms, bone metabolism, healing (e.g., protein deficiency), and direct toxic effects on periodontal tissues (Tezal et al. 2004). Additional information on tobacco, marijuana, and alcohol use and oral health is provided in Section 5.

Oral Health Disparities and Inequities

Following the 2000 Surgeon General’s report on oral health’s Call to Action to address oral health disparities (U.S. Department of Health and Human Services 2003), additional reports and recommendations were published by other entities with a similar message (Nelson 2002; Institute of Medicine 2011a; Hill et al. 2015; Fischer et al. 2017). New research funding and other initiatives to gather population-level data followed (Fischer et al. 2017). Some progress has been made to better understand the broad influences and general complexity underlying oral health disparities, enabling better progress in the future. There now exists some information on Asian American oral health status because the National Health and Nutrition Examination Survey (NHANES) oversampled this group when conducting the latest oral health survey. Oversampling is a technique used to increase the sample size of a population previously underrepresented in population surveillance efforts (Paulose-Ram et al. 2017). This oversampling facilitated the first reliable estimates of dental caries and tooth loss in Asian Americans (Dye et al. 2015; Eke et al. 2015), revealing that among working-age adults, compared with non-Hispanic Whites, Asian Americans have a caries experience more similar to that of Hispanics and non-Hispanic Blacks, although the prevalence of untreated caries is more similar to that of non-Hispanic Whites.

Progress also has been made among American Indian/Alaska Native adults, who have historically suffered disproportionately from oral disease; the gap between them and the general population has been gradually declining. In fact, this population’s oral health status has slightly improved during the past 2 decades, such that “fewer have untreated decay, the prevalence of severe periodontal disease has decreased, and more adults are keeping their teeth into older age” (Phipps and Ricks 2016).

The challenge ahead is to move from research focused on identifying differences in health to improving our knowledge of factors that contribute to disparities and discovering interventions that will reduce them (Dye et al. 2019b). Although disparities in adult oral health are well documented, the relationships and interactions of the many factors that contribute to these disparities are not well understood. Several factors—including discrimination, food deserts, limited transportation, and limited access to medical/dental care—disproportionally affect minorities, low-income groups, and other underserved populations (Sheiham and Watt 2000; Gehlert et al. 2008). The impact of other population-level factors on oral health, such as housing quality and unemployment, need to be better understood across all populations, including adults (Watt 2007). These factors increase the risk for adverse health conditions, including poor oral health, and contribute to documented oral health disparities (Patrick et al. 2006). To effectively address oral health disparities across the lifespan, interventions need to target these population-level factors (Gehlert et al. 2008).

There has been some movement toward partnerships among health care systems and community-based organizations to address SDoH, but these types of interventions are complex, expensive to implement, and require new collaborations and funding mechanisms (Watt 2007). For example, the NCCare360 initiative in North Carolina, which works on state Medicaid transformation, connects health care and human services organizations with shared technology, resources, and coordinated care; however, it does not yet include oral health care (NCCare360 2021). Overcoming these obstacles is mandatory to create interventions that are population-specific, implementable at community and individual levels, and produce observable and lasting changes.

Pregnancy and Oral Health

Even though having good oral health during pregnancy is important, challenges have persisted for encouraging pregnant women to seek dental care and encouraging oral health professionals to provide care (Huebner et al. 2009). Recently, a group of investigators (Stephens et al. 2020) has issued a call to action regarding efforts to increase use of dental services during pregnancy. Having found that fewer than 20% of Medicaid-eligible pregnant women in 2014–2016 received dental care in North Carolina during pregnancy, they call for a multidimensional approach focusing on patients, providers, and policymakers to take action. These recommendations include conducting educational campaigns to increase public awareness and knowledge of the importance of dental care during pregnancy, improving health professional education and training on the importance and safety of treating pregnant women, expanding the workforce, and extending dental benefits.

Oral health providers should recognize that dental treatment during pregnancy is safe, does not affect the fetus, and that there is no need to postpone or avoid oral health care (American College of Obstetricians and Gynecologists 2013; Hagai et al. 2015). The ADA has acknowledged that preventive, diagnostic, and restorative dental treatment to promote health and eliminate disease is safe throughout pregnancy and is effective in improving and maintaining the oral health of mothers and their children (American Dental Association 2019). Continuing challenges in oral health for pregnant women are the integration of oral health into prenatal classes for expectant mothers, the addition of aspects of oral health during pregnancy in obstetrics and gynecology and midwife education, and better education of the dental community in regard to the need for, and safety of, dental care during pregnancy.

Effects of Cancer Treatment on Oral Health

Despite scientific and clinical advances, challenges remain regarding the impact of the oral complications of cancer therapy on people’s lives. For example, the ability to maintain employment is compromised because of functional changes and aesthetic concerns that result from treatment. The time and cost of medically necessary oral care before, during, and after cancer treatment also increases the probability of financial difficulty (Mady et al. 2019). Other challenges include access to care, health inequities, education of dental practitioners, and facilitating research that develops relevant information to support evidence-based decision making that leads not only to better health outcomes, but improves quality of life.

HIV

The 2000 Surgeon General’s report on oral health recognized that the early identification of oral manifestations of HIV showed promise in helping to diagnose and manage HIV disease sooner. Public health programs initiated during the past 20 years have focused on early detection of HIV disease as a way to establish and facilitate care. New antiretroviral therapy has transformed HIV from a fatal illness to a chronic, manageable disease. Antiretroviral medications can sustain HIV viral suppression, reducing HIV transmission (Li et al. 2019) and the oral manifestations of HIV infection (Patton et al. 2000; Tami-Maury et al. 2011). In fact, incidence of the two most common oral manifestations of HIV, oral candidiasis and oral hairy leukoplakia, have decreased with rising immune competence (Chattopadhyay et al. 2005). Although the use of highly active antiretroviral therapy has resulted in significant reductions in HIV-related oral leukoplakias, some are still seen in patients with HIV infection. However, oral candidiasis remains the most common lesion seen with HIV infection (Patton et al. 2013).

Sickle Cell Disease

Improving oral health outcomes in people with sickle cell disease (SCD) remains a challenge. Patients with SCD should receive a thorough diagnosis and comprehensive options for dental treatment in consultation with their primary care provider or oncologist. Because there is insufficient evidence in the literature to guide oral health practitioners on the dental management of SCD patients and there are no guidelines on how to treat dental complications in patients with SCD, these patients may not receive appropriate treatment. However, the recent recommendations made by Kawar and colleagues (2018) (see also Appendix) provide a useful guide to dental care for individuals with SCD. These recommendations include:

• A healthy diet, routine dental checkups, and regular oral hygiene maintenance to prevent or at least minimize oral health-related complications. Patients should have oral health screenings provided by a dentist at least every 6 months.
• Minimize stress during dental treatment, because stress is a well-known factor that provokes a sickle cell crisis. Short morning visits are recommended for SCD patients, with anxiety assessment at the initial visit.
• Prevention and early management of any potential source of infection from gingival, periodontal, or endodontic origin. Dental infections should be treated aggressively with local and systemic measures.
• Encourage protective factors that promote teeth remineralization.
• Referral to an orthodontist for treatment of occlusal and skeletal discrepancies.

Laurence and colleagues (2013) observed a relationship between the presence of a dental infection and an increased likelihood of hospital admission among adult patients with SCD. The authors concluded that an increased focus on preventive oral health may reduce hospital admissions following visits to the emergency department. The challenge is to make more preventive and basic dental care accessible to patients with SCD and to help them take full advantage of available dental care.

Medications and Oral Health Complications

As mentioned in Chapter 1, among the most common oral side effects of some commonly prescribed medications is a decrease in salivary flow, leading to drug-induced xerostomia (dry mouth). It can be a challenge to recognize and manage the oral health side effects from these medications. Because the prevalence of some of the conditions related to these medications increases with age, the risk for caries may increase, as well. With an aging population in the United States and increasing prevalence of more chronic health conditions with increasing pharmacologic management, managing decreased salivary flow will become an increasing challenge. Doctors prescribing these medications and pharmacists who dispense them should be educated to inform their patients about the risk for dry mouth, including increased risk for dental and root caries, as well as other side effects that can potentially impact oral health. See Section 3B for more information on xerostomia and dry mouth.

Management of Dental Caries

During the past 2 decades, there has been a change in our approach to prevent, diagnose, and manage this disease. An important aspect of this change has been a minimally invasive, nonsurgical approach to dental caries management that requires a documented assessment of risk, application of a remineralization treatment, and the ability to track changes in demineralization.

The use of fluorides continues to have an important role in preventing and controlling dental caries among working-age adults, but new information during the past decade is helping us to better understand how fluorides can be used effectively for this age group. Although some studies have suggested that community water fluoridation can be effective in preventing caries in adults (Griffin et al. 2007; Slade et al. 2013b), a large scale systematic study found insufficient evidence among adults, because the available studies did not meet the study criteria (Iheozor-Ejiofor et al. 2015). Nevertheless, other topical fluorides—in the form of rinses, gels, and varnishes—have been shown to be effective in adults who are at risk of developing caries (Weyant et al. 2013; Canadian Agency for Drugs and Technologies in Health 2016). However, a 2016 Canadian governmental review of the clinical and cost-effectiveness of fluoride varnishes concluded (with moderate certainty) that youth up to 18 years of age can benefit from the application of fluoride varnish biannually for the prevention of dental caries, while for adults, the strength of the evidence was lower and more directed to preventing dental caries occurring on exposed tooth roots. In general, the evidence summarized during the past decade has led to guidance for dental clinicians in the United States to prioritize the use of prescription fluoride (1.1% NaF) toothpaste or gel to reverse noncavitated lesions or to arrest smaller cavitated lesions on root surfaces of permanent teeth (Slayton et al. 2018). For more advanced cavitated lesions on permanent teeth, the guidance is to prioritize the use of silver diamine fluoride (SDF) biannually.

SDF is an inexpensive, noninvasive addition to the fluoride armamentarium and has re-emerged in the last decade as an important intervention to prevent and control dental caries on exposed tooth roots in adults. The use of fluoride varnish with 38% SDF, a silver fluoride salt, has been cleared by the FDA for hypersensitivity in adults, which makes its use to arrest dental caries in children and adults an off-label application (more information on SDF use in children is provided in Section 2A). As a noninvasive intervention, it has been reported that SDF can be beneficial to use in adults for whom patient cooperation is difficult because of complex medical or behavioral concerns, or when other unique circumstances must be considered, for example, in hospital settings or other places such as nursing homes (Horst et al. 2016). The application of this material does not replace the form or function of the tooth as does traditional restorative dental care. It is advisable to apply SDF to cavitated teeth with a plan for restorative care, so the cavitated lesions do not act as a reservoir for bacteria that promote tooth decay.

The longevity of restorations has not changed significantly in the past 2 to 3 decades, despite improvements in dental materials. Each time a restoration is replaced, it destroys more tooth structure. Results of clinical trials suggest that most restorations placed with current dental materials should last a relatively long time; however, early restoration failure is common, and replacement accounts for more than half of all restorations (Eltahlah et al. 2018). The challenge lies in helping dentists understand when to restore or replace a restoration and if remineralization is an option. If cavitation is not present, the cost of dental care can be reduced, and outcomes can be improved by choosing to remineralize a tooth.

Management of Tooth Loss and Replacement

The use of osseointegrated dental implants to replace missing teeth in working-age adults has increased considerably during the past 20 years. Implants are used to replace single missing teeth (Figure 27) and to support removable dentures. Each dental implant procedure may cost $3,000 or more, which includes the implant, the abutment, and the crown.

Figure 27

Dental implant.

During the past 20 years, the percent of working-age adults obtaining at least one dental implant has tripled, from less than 1% to nearly 3% (Table 6). The greatest difference in the prevalence of dental implants among working-age adults is between those living in poverty and those who are more affluent; that difference has increased significantly in the last 2 decades. Adults with educational attainment beyond high school or with private dental insurance are twice as likely to have dental implants than those with lower education or no insurance (Elani et al. 2018). Throughout that time, improvements have been made in implant materials, coatings, threads, and shapes to improve the osseointegration process, as well as the health of the surrounding oral tissues (Buser et al. 2017). Additional improvements aimed to improve access to this costly treatment include reduction of the number of implants needed to retain prostheses (Bryant et al. 2015) and the use of narrow-diameter implants (de Souza et al. 2015). Current practice addresses issues important to patients, such as immediately placing implants following tooth extraction, early and immediate loading of implants so that patients do not need to live for weeks without a prosthesis, less invasive surgical techniques, and newer attachment designs so that patients can easily place and remove their prostheses (Buser et al. 2017).

Table 6

Percentage of adults ages 20 and older with at least one dental implant present by select characteristics: United States, 1999–2004 and 2011–2016.

New technologies, such as cone beam computed tomography imaging, and computer-assisted design and computer-assisted manufacturing (CAD/CAM) approaches, are used for more precise implant placement and prosthetic fabrication (Buser et al. 2017). The use of two implants to retain complete dentures in the mandible (lower jaw) has been shown to be more satisfactory for patients and provide greater oral health-related quality of life than new complete conventional dentures (Kodama et al. 2016).

Important challenges persist in educating patients when they are about to undergo extensive restorative dental treatment. When considering both tooth- and implant-borne, single- and multi-tooth restorations such as crowns, fixed partial dentures (bridges), and implant-supported prostheses, there is a critical need to educate patients on how to maintain complex restorations and improve the longevity of restorations (Bidra et al. 2016a; 2016b).

Unfortunately, most prosthodontic treatments, such as dentures, bridges, and implants, are available only to those who can afford them by using dental insurance benefits and/or paying out of pocket. As noted above, federal and state support for oral health care is limited to Medicaid (Title XIX of the Social Security Act), which provides some health benefits to people with limited income—mainly pregnant women, some adults with dependents, people with disabilities, and older adults. Of the states that do offer Medicaid benefits for adults, coverage varies considerably and often is restricted to emergency dental services. The lack of availability of dental bridges and implants may be further increasing oral health inequity. Although dental implants to replace single and multiple missing teeth are increasingly seen as the best treatment option in adults, they are financially out of reach for many working-age adults.

Managing Opioid Prescriptions to Prevent Misuse

Prescription opioids—such as Vicodin, OxyContin, and Percocet, among others—are typically provided by dentists and other health providers to manage orofacial pain. In response to the opioid addiction crisis, dental professionals have substantially changed their prescribing practices and have reduced the proportion of all prescriptions for immediate-release opioid analgesics to outpatients by more than half in the past 20 years (15% to 6%) (Gupta et al. 2018). In contrast, primary care providers were the leading prescribers of all outpatient opioid analgesics, prescribing about half of those in 2012 (Denisco et al. 2011; Levy et al. 2015).

During the last decade, the trend to prescribe fewer opioids has accelerated. The estimated number of opioid prescriptions decreased from 69.3 million in 2010 to 63.4 million in 2018 for all drug classes combined. Opioid analgesics were the second most common drug class prescribed by dental providers, after antibiotics, with about 11.6 million prescriptions dispensed in 2018, a 43% decrease from 20.5 million prescriptions in 2010. Of note, the number of dispensed nonsteroidal anti-inflammatory drug (NSAID) prescriptions written by dental providers increased by 67%, from 4.5 million in 2010 to 7.5 million in 2018, despite the availability of over-the-counter NSAIDs (Symphony Health PHAST™ Prescription Monthly Database Data extracted May 2019).

The few studies that have evaluated the prescribing patterns of opioid analgesics by dentists reported that overprescribing was the result of a cautionary approach, generally associated with an overestimate of potential postprocedural pain (Wong et al. 2016; Thornhill et al. 2019). Nevertheless, in the last decade, policies implemented by professional organizations and a tightening of state prescribing authorities have resulted in declining dentists’ opioid prescriptions. Opioid misuse is discussed further in Section 5.

Dental Fear and Anxiety

Management of dental fear and anxiety should begin with a thorough, individualized assessment of symptoms and potential causes (McNeil and Randall 2014). Pharmacologic approaches such as conscious sedation and general anesthesia, though commonly used, are not likely to yield long-term reductions in fear, anxiety, or avoidance (Boyle et al. 2009).

Since 2000, experts have recommended the use of behavioral approaches to the management of dental fear/anxiety in adults, reserving pharmacologic interventions for cases of high fear/anxiety and urgent need for dental treatment (Boyle et al. 2009; Newton et al. 2012). Evidence-based behavioral interventions include exposure therapy and skills training, as well as educating patients, building trust and rapport, enhancing sense of control, distraction, and offering positive reinforcement. In addition, cognitive-behavioral therapy may encompass relaxation training, cognitive restructuring, and systematic desensitization (Armfield et al. 2007). Many of these strategies are delivered by trained dental personnel in the dental setting, with referral to a clinical psychologist for severe cases. They may be used as part of an integrated behavioral-pharmacologic approach to management when clinically indicated (Boyle et al. 2009; McNeil and Randall 2014).

Digital Dentistry and CAD/CAM Technologies

Convergence of software development and hardware technology has increased the ability to plan oral care and has enhanced and improved care for many adults. Since the introduction of CAD/CAM systems in the 1970s and 1980s (Duret et al. 1988), their use continues to evolve. These digital technologies have driven improvements in diagnosis and treatment planning (Bhambhani et al. 2013; Cooper and Ludlow 2016), as well as the development of new and better materials for dentistry, including indirect restorations to replace teeth. Although ceramics, metals, and polymers have been used in dentistry for many years, the advent of CAD/CAM technology has improved the use of these materials, resulting in better outcomes for patients through improved precision.

CAD/CAM systems include the use of digital radiographic imaging, color matching and shade selection, photographic imaging, intraoral and extraoral scanning to capture anatomical features and inanimate objects, and computer-assisted pantographic recording of mandibular jaw movement. For capture of inanimate objects, extraoral scanners include optical, laser, and touch probe methods. The resulting images are then used in diagnosis and treatment planning.

CAD/CAM systems also make possible tooth preparation and restoration in one visit. Restorations can be fabricated chairside in reasonable time frames, reducing the number and length of appointments. At the same time, this new technology has opened access to new, better-performing materials for restorations and prostheses—to the point where restorations and prostheses fabricated by modern CAD/CAM systems are clinically equivalent to, and sometimes better than, those created with conventional methods (Ahmed 2018; Alshawaf et al. 2018; Kirschneck et al. 2018; Benic et al. 2019; Dickens et al. 2019; Wang et al. 2019).

Digital images can be created using optical or ionizing radiation energy sources (intraoral scanners or digital two-dimensional and three-dimensional radiographs, respectively). Both are easily shared electronically among health care providers. Intraoral scanning technologies have proliferated since the original CAD/CAM systems. Now, full arch, full color, high resolution images are captured in minutes. Captured data, displayed on a computer screen, are an important asset for patient consultation. Not surprisingly, patients much prefer images captured by a 1-inch diameter intraoral scanner than conventional impression methods that can be uncomfortable, or even painful (Burzynski et al. 2018; Sailer 2018).

Advances in Consumer Dental Products

There have been considerable advances in consumer dental products in the past 20 years. Most notably, many powered toothbrushes are available today, along with new toothpastes, antimicrobial rinses, and tooth-whitening strips. Powered toothbrushes are designed with different modes of action (oscillating-rotating, sonic, counter-oscillating, side-to-side, and back-and-forth). A Cochrane review found that, when compared to manual tooth brushes, oscillating-rotating power toothbrushes (relative to other modes of action) were more effective in reducing plaque and gingivitis in the short- and long-term (Yaacob et al. 2014). A recent systematic review (Rosema et al. 2016) evaluated the efficacy of powered toothbrushes on pre- and post-brushing plaque scores in a dataset of 6,713 participants. The review found that a weighted mean of 46% in plaque reduction was achieved following a brushing exercise. Similarly, another review (Yaacob et al. 2014) conducted a meta-analysis of 51 clinical trials involving 4,624 participants and found an 11% reduction in plaque in the short term (1–3 months) and a 21% reduction in plaque in the long-term (more than 3 months). Another meta-analysis conducted in the same review found 6% and 11% reductions in gingivitis in the short-term and long-term, respectively. Newer oscillating-rotating powered toothbrushes use Bluetooth technology to connect with a consumer’s smartphone to provide an interactive brushing experience.

Adults with Disabilities and Special Health Care Needs

Major changes during the past 2 decades have had a significant impact on the oral health of adults with disabilities and special health care needs (SHCNs). These changes include provisions within the ACA that have benefitted a broad population, especially young adults with special needs. These include expanded Medicaid eligibility to low-income adults without dependent children; dependent care coverage on parents’ policies until 26 years of age; expanded health insurance; and, to a lesser extent, dental coverage for previously uninsured populations. These changes have resulted in improved access to needed oral health care for some adults with disabilities and SHCNs in selected states that have expanded their Medicaid coverage. However, inconsistent dental coverage across the country continues to limit the ability of many in this vulnerable group of people to achieve or maintain optimal oral health.

The availability of trained dental providers who feel comfortable providing prevention, treatment, and disease management for adults with SHCNs remains a challenge in achieving oral health for this population. According to Families USA, this is a serious problem (Families USA 2019). However, progress is underway in educating dental students and dental residents to care for adults with complex medical conditions and special needs. For example, the Commission on Dental Accreditation has recently approved a new standard for predoctoral education that requires all U.S. dental schools to educate students to be competent in assessing and managing patients with intellectual and developmental disabilities, among other special needs populations. By mid-2020, all schools must comply with this educational standard or risk jeopardizing their accreditation (Commission on Dental Accreditation 2019).

Incarcerated Populations

Incarcerated individuals face oral health challenges, even after their incarceration ends. Release from jail or prison frequently means interruptions in care, as well as the tasks of finding providers and obtaining insurance or other means to pay for care. Poor dental health and tooth loss may make it more difficult to find employment. In short, a history of incarceration remains a significant factor in the unmet medical and dental needs of former prisoners (Kulkarni et al. 2010). It is evident that incarcerated people should be designated as an underserved population based on their demographics, limited access to adequate oral health care, increased likelihood of facial trauma, and continuing health care challenges. Unfortunately, meeting the health needs of the large U.S. prison population, both during and after incarceration, remains a challenge.

The high incidence of oral diseases, the increased prevalence of disease risk factors, and limited access to dental services are significant challenges for this population. These challenges extend beyond release from incarceration and affect these individuals’ families and communities. Developing and implementing recommendations to better support the oral health of those formerly incarcerated would improve population health outcomes.

Rural Communities

People living in rural communities often have limited access to dental care. Geographical distances, especially for Native Americans living in tribal communities, make dental care even more scarce and may require many miles of expensive and time-consuming travel.

Addressing the oral health inequities that still exist among rural and Native American populations is a significant impediment in reaching objectives for Healthy People 2030. Specifically, if the Indian Health Service and tribal programs are to meet the Healthy People objectives for untreated decay, considerable progress must be made in developing preventive programs and improving access to and utilization of the dental care system.

A recent review (Tiwari et al. 2018) of studies aimed at reducing health inequities among indigenous communities included communities from the United States, Canada, Brazil, Australia, and New Zealand. The interventions largely focused on early childhood caries but several also addressed outcomes among adults, including oral health literacy (Ju et al. 2017), the efficacy of an oral health literacy intervention among Indigenous Australian adults (Ju et al. 2018), and periodontal health among Indigenous Australians (Kapellas et al. 2013). Both oral health literacy and periodontal health improved in these studies. The authors identified common methodologies and challenges. The common methodologies included culturally-tailored interventions, community-based interventions, and community workers to deliver the interventions. The studies faced challenges because the communities were spread over vast areas and remote locations and required resource intensive interventions that would be difficult to scale up for broad implementation.

Lesbian, Gay, Bisexual, Transgender, and Queer (LGBTQ) Oral Health

Estimates of the percentage of lesbian, gay, bisexual, transgender, and queer (LGBTQ) people include about 6.8% of men and 4.5% of women over the age of 18 who self-identify as lesbian, gay, or bisexual, thus representing a fairly substantial proportion of the U.S. population (Russell and More 2016). As recently as 20 years ago, oral health in the LGBTQ community received only a brief mention in the 2000 Surgeon General’s report on oral health, which noted the lack of data and the need for more research for this population. A limited number of studies have since begun to address this gap in knowledge (Russell and More 2016).

Although LGBTQ people are a heterogeneous group, they share experiences of discrimination and social stigma in the broader society as well as in the health care system, resulting in health inequities. A study of sexual orientation and health based on data from the 2001–2008 Behavioral Risk Factor Surveillance System surveys (N=67,359) in Massachusetts found that, compared to individuals who identify as heterosexuals, gay/lesbian and bisexual individuals reported more disability, worse mental health, and more frequent health risk behavior, such as smoking and drug use (Conron et al. 2010). Bisexuals experienced greater cardiovascular disease risk and barriers to health care. Another study based on Behavioral Risk Factor Surveillance System surveys from 2005–2010 in seven states suggested that the health inequities experienced by LGBTQ people are derived from poor economic circumstances and social disadvantages, compared to heterosexuals (Gorman et al. 2015).

Data on the oral health of LGBTQ people are more limited than that on medical conditions. Schwartz and colleagues (2019) indicated that the analysis of oral health data for LGBTQ people did not even exist before their study of NHANES data from 2009 to 2014. The authors investigated health inequities among lesbian, gay, and bisexual adults aged 18 to 59 years, relative to heterosexual adults. They examined clinical indicators, including dental caries, tooth loss, chronic periodontitis, and oral HPV, as well as self-reported oral health status and use of dental services. They did not find any differences in clinical oral health status between lesbian, gay, and bisexual adults, compared to heterosexual adults, although lesbian, gay, and bisexual adults reported worse perceived oral health. This study is the first to shed light on the oral health of LGBTQ people. Clearly, more research is needed on the oral health inequities that LGBTQ people experience.

Community and Family-Based Interventions

Progress during the past decade has included the development and implementation of intergenerational and family-based interventions for rural and immigrant communities. Many of these emphasize university-community partnerships, often using community-based participatory research (CBPR) and qualitative approaches and methods (Huebner et al. 2014; Kavathe et al. 2018). Such interventions recognize that intergenerational influences—including caregivers’ attributes, attitudes, and knowledge—may be viewed as intermediary mechanisms through which societal and community influences affect the oral health of family members, particularly in disadvantaged communities (Milgrom et al. 2013; Northridge et al. 2017b). According to a review by Tiwari and colleagues (Tiwari et al. 2018), preferred intervention methodologies included community-based research approaches, culturally tailored strategies, and use of community workers to deliver the initiative. CBPR methods also have been used for examining attitudes, perceptions, and barriers toward oral health and oral health care seeking. The variety of populations and contexts for this work has included one involving Black men living in low-income, urban communities (Hoffman et al. 2017; Akintobi et al. 2018) and another that focused on migrant Mexican families involved in oral health educational interventions (Finlayson et al. 2017).

Advances in Periodontal Disease Diagnostic Staging and Influence on Dental Implant Success

New genomic and statistical technologies have led to the redefinition and reclassification of periodontal disease (Caton et al. 2018a). This change in periodontal disease classification is expected to help improve diagnosis and treatment decision making, leading to better prognoses and outcomes for patients (Tonetti and Sanz 2019). In addition, recent information is improving our understanding of peri-implantitis (inflammation forming around dental implants), including risk factors and indicators that favor onset and disease progression (Berglundh et al. 2018a; Schwarz et al. 2018a; Berglundh et al. 2018b; Schwarz et al. 2018b). Given the increased use of dental implants among adults, this will help to guide decision making and reduce implant failure.

Orofacial Pain and Temporomandibular Disorders

The recent U.S. National Pain Strategy, an interagency initiative launched in 2017 by the U.S. Department of Health and Human Services (National Institutes of Health 2021a), addresses many aspects of pain relevant to temporomandibular disorders (TMD). This initiative is beginning to provide robust national data on the personal and societal impact of chronic pain (Dahlhamer et al. 2018) and is expected to help prioritize effective treatments to reduce the impact of pain. Furthermore, the proposed incorporation of TMD into the Institute for Health Metrics and Evaluation’s Global Burden of Disease Study will provide data on the impact of TMD around the world. Finally, ongoing research on factors related to susceptibility to multiple pain conditions will likely yield new findings, allowing for early targeting of effective interventions for TMD patients at risk for high-impact chronic pain.

The opioid crisis, although focused primarily on decreasing the number of opioid prescriptions written by dentists, also is leading dental professionals to a new understanding about acute and chronic pain in their patients. This effort assists dental clinicians in the management and treatment of patients with TMD.

Oropharyngeal Cancer and Human Papillomavirus

Research has revealed the epidemiologic underpinnings and clinical implications of oropharyngeal cancer caused by the human papillomavirus-related oropharyngeal squamous cell cancer (HPV-OPC), yielding a clearer understanding of the disease process. At the same time, there is much to learn about the pathogenesis of oral HPV infection. Although the HPV vaccine offers great promise in preventing future cases of OPC, questions remain about the minimum serologic titer needed to be protective and how this might affect the vaccine’s long-term impact upon HPV-OPC. With the increasing burden of HPVOPC, it is important for researchers to develop an effective screening strategy by addressing questions related to whether there is an identifiable precursor lesion and who is at risk for persistent infections that lead to malignant transformation. This work will involve seeking potential biomarkers to identify individuals at increased risk for malignancy and factors that influence the cascade from infection to malignancy. It also will be important to develop diagnostic tools to aid in early identification of lesions and to determine whether early detection can result in less therapy, less morbidity, and improved survival. Finally, investigators should explore the potential of early patient education for reducing the incidence of OPC.

Managing Effects of Cancer and Other Treatments on Oral Health

There are several strategic research directions to increase our knowledge of the unique oral health challenges faced by cancer patients being treated with pharmacologic agents and of strategies for improving their dental management. Research opportunities include: (1) mechanistic-based research addressing bone and oral mucosal biology and the genetic risks for developing medication-related osteonecrosis of the jaw; (2) continued population health studies regarding antibiotic prophylaxis for prevention of infective endocarditis and prosthetic joint infection; and (3) novel health professional curricula to encourage interprofessional education and practice.

In addition to cancer treatments, many medications affect oral tissues, notably those that cause xerostomia, salivary hypofunction (Wolff et al. 2017), and gingival hyperplasia (Aral et al. 2015). In addition, the dental management of patients can be influenced by anticoagulant/antiplatelet medications (Mingarro-de-Leon et al. 2014; American Dental Association 2018b), the use of prophylactic antibiotics for those with prosthetic joints of the hip or knee (Sollecito et al. 2015), and individuals who have cardiac risk factors for infective endocarditis (Wilson et al. 2008; Nishimura et al. 2017). Clinical guidelines developed jointly by physicians and dental clinicians can improve management of these medically complex patients.

Managing Opioid Prescriptions to Prevent Misuse

Partnerships among various stakeholders at national, state, and community levels have led to significant successes in mitigating prescription opioid misuse, abuse, and overdose deaths. Federal agencies are developing additional initiatives and strategies. For example, the National Institutes of Health, through the Helping to End Addiction Long-term Initiative, is advancing the development of new and innovative medications and biologics for the prevention and treatment of opioid misuse and addiction and to enhance nonaddictive pain management (National Institutes of Health 2020).

The U.S. Food and Drug Administration (FDA) also is committed to the development of safe, effective nonopioid analgesics and new medications to treat opioid use disorder. In May 2018, FDA launched an innovation challenge to develop medical devices to combat the opioid crisis. In April 2019, the agency approved the first generic naloxone hydrochloride nasal spray (Narcan), a life-saving medication that can stop or reverse the effects of an opioid overdose. The agency is supporting the development of over-the-counter naloxone to increase access to this critical drug for reducing opioid overdose deaths (U.S. Food and Drug Administration 2015; 2017; 2019).

On the state level, policies and laws that curb the prescribing of opioids by dentists have emerged. States are changing their dental practice acts to include mandatory continuing education on opioid use and abuse and requirements for dentists to register for and use state-based prescription drug monitoring programs before prescribing an opioid analgesic for chronic or acute pain.

Nonsurgical Treatment Innovations

Nonsurgical treatment approaches, such as therapies based on fluoride agents such as silver diamine fluoride (SDF), frequently are good alternatives to problems commonly addressed by dental surgical procedures and are beginning to represent new standards of care. Further progress is possible with better implementation of evidence-based treatments, such as fluoride varnish and SDF, and development of new therapies.

Regarding treatment, the American Dental Association Center for Evidence-Based Dentistry and other organizations have developed evidence-based guidelines for the prevention and management of dental caries. Yet, changes in clinical practice appear to be occurring at a relatively slow pace, in large part because the dental care reimbursement system continues to reward the restorative management of disease, rather than value-based care.

Similarly, nonsurgical approaches to the treatment of periodontal disease continue to be developed. These nonsurgical approaches are based on research findings that have shown how to decrease the bacteria that cause periodontal disease. New treatments for dental sensitivity also continue to be developed. Changes in treatment standards and practices are just one aspect of an evolving landscape for oral health care. Many patients now come to the oral health professional with a great deal of knowledge about their condition, often obtained from web searches (Seymour et al. 2016). They are actively engaged in monitoring and managing many other aspects of their health, e.g., using wearable devices that track and report activities, exercise, sleep, heart rate, glucose levels, and more. Similar technologies for oral health could be valuable additions to these options. Some electric toothbrushes already monitor the recommended brushing time of 2 minutes.

These nonsurgical approaches for both dental caries and periodontal disease, in addition to the more traditional surgical approaches to managing dental diseases, can help adults keep their teeth throughout their life. Point-of-care devices for monitoring daily oral home care will continue to be developed and assist working adults to maintain good oral health as they age.

New Technologies for Dentistry

Digital technologies are transforming clinical dental practice. These new technologies are making clinical dental care faster, easier, and more precise. Digital technologies have become the most promising platform for creating clear communication among dental professionals, patients, dental laboratories, and insurers. The quality of data enhances workflow, recordkeeping, and therapeutics. These technologies also have delivered diagnostic improvements, lowered radiology exposure rates, and simplified processes.

With digital technologies, it is now possible to integrate data from multiple sources, including digital optical and radiographic data; computer-assisted design/computer-assisted manufacturing (CAD/CAM) restoration design and fabrication commands; patients’ medical, social, and dental status; progress notes; and treatment plans drawn from electronic health records (EHRs). Using some or all of these data facilitates referrals and conversations between dental and medical professionals about patient care and enhances the interoperability of EHRs.

A potential and promising new use of CAD/CAM systems is the opportunity to use them in underserved areas. For instance, a mobile van using these systems could deliver care to underserved areas, including nursing homes, prisons, and rural areas with no permanent onsite dental clinician. Use of CAD/CAM systems in such settings could result in restoration, rather than extraction, of teeth and lead to improved oral health for many working-age rural adults.

Teledentistry is another promising new direction that can expand the provision of oral health services to those who cannot easily access dental care, including patients who are homebound or live in rural areas (Cooper and Ludlow 2016; Estai et al. 2018; Kopycka-Kedzierawski et al. 2018). Teledentistry can be used for a variety of services. For example, intraoral scans, even those captured by cell phones, enable data collection for screening and diagnosis from afar (Giraudeau et al. 2017; Signori et al. 2018; Binaisse et al. 2019; Giacomini et al. 2019). In the future, workplace and school-based screenings could be done without the need for highly skilled examiners onsite (Tynan et al. 2018).

To more completely integrate new technologies into clinical practice will require incentives that encourage providers and patients to embrace digital dentistry. Reimbursements, especially for remote services and teledentistry activities, will be critical. Reimbursement for outcomes-driven and prevention-focused oral health care—regardless of the delivery mode—has become increasingly important (Shetty et al. 2018).

Artificial intelligence (AI) systems, which recognize trends and patterns in large datasets, then refine projections with exposure to more data, offer promising new opportunities to improve not just clinical treatments, but the training of clinicians. AI systems have been trained to review radiographs and diagnose tooth decay. Other uses in oral health are emerging. Virtual, augmented, and mixed reality are being used to create virtual patients that can be used for training or enhancing the treatment of existing patients (see Section 6 for more on AI).

Oral Health Literacy

One promising new direction in the area of improving oral health literacy is a recent initiative focused on Native Americans. In 2019, the Indian Health Service (IHS) created the IHS Oral Health Literacy Initiative to give dental professionals tools to improve oral health literacy among the American Indian/Alaska Native population. The theme for this initiative is SMILE—Sharing oral health Messages to Improve Literacy for Everyone. This innovative oral health literacy initiative includes oral health materials and an oral health literacy presentation for dental professionals to offer patients (Indian Health Service 2021).

In addition, companies such as GoodHealthTV^® provide oral health information to more than 200 IHS, tribal, and urban clinics through subscription-based health education networks broadcast in clinic waiting areas. According to GoodHealthTV^®’s website, 99% of viewers indicated they watched and learned new information, and 92% said that the programming prompted them to seek more information (GoodHealthTV 2018). The use of digital and social media is another way to reach individuals in Indian country with targeted oral health messages. Additional research is warranted to demonstrate that improved oral health literacy results in improved oral health outcomes (Horowitz et al. 2020).

Community-Based Interventions

Promising new directions to improve oral health equity for working adults include embedding clear, culturally appropriate messages on oral health within community-based health interventions, such as those for tobacco prevention and cessation, nutrition, injury prevention, HPV vaccination, and diabetes education (Benzian and Williams 2015). Moreover, the broad reach of mobile and other digital technologies provides opportunities for remote monitoring and self-care to reinforce preventive oral hygiene behaviors (Shetty et al. 2018) at the individual level. For researchers, community-based participatory research, qualitative approaches, and implementation science hold promise to address barriers to community-based oral health promotion (Simpson 2011).

Given cultural influences on health attitudes and behaviors and the potential for isolation of some new immigrants, community institutions and community health workers may serve as cultural bridges that can link immigrants to needed oral health information and resources (Marino et al. 2014; Kavathe et al. 2018). Community-based peer support programs aimed at diabetes prevention or tobacco cessation also may improve oral health among underserved adults (Thankappan et al. 2018).

Community Programs Targeting Special Needs Populations

Achieving optimal oral health among adults with disabilities and special health care needs is a complex undertaking. Although progress is being made and some programs are showing promise, achieving this goal will require broader and more sustained efforts affecting systems change. Promising new directions that demand further evaluation and expansion include the education of dental clinicians and specialists in preventing and treating dental diseases in this vulnerable population (Dao et al. 2005). Also promising are programs that provide a public or private dental insurance benefit for adults and older adults, regardless of employment, to improve access to needed oral health services (Wehby et al. 2019).

In addition, many working-age adults with complex health needs are military veterans who may have service-related conditions such as post-traumatic stress syndrome, risk for substance use disorders, homelessness, or any number of other health conditions and limitations. Many of these conditions can substantially affect access to dental care, leading to poor oral health. An example of a community service designed to improve the oral health of military veterans is the Heroes Clinic in Denver, Colorado. A partnership between the University of Colorado School of Dental Medicine and Delta Dental of Colorado, this clinic provides a range of free dental services to veterans and can even accommodate their service dogs (Box 1).

Interprofessional Care

There is some evidence that interprofessional practice improves patient outcomes (Reeves et al. 2017). Although interprofessional, integrated, personalized care is a promising approach to achieve health equity and eliminate oral health disparities, most work in interprofessional care has been done with children, rather than adults. Interprofessional collaborations have occurred for special needs adults with developmental disabilities to improve their oral health (Fenton et al. 2003). Although some interprofessional collaborations have been developed for adults, many of these are hospital-based and focus on adults with various severe medical diseases, and oral health has not been universally incorporated. There has been an attempt at integrating some oral health care for pregnant women in places where they most frequently seek care and counseling. One example is Grace Health in Michigan where dental hygienists are co-located in an obstetrics suite (Atchison et al. 2018), and another is prenatal care centers operated by CenteringPregnancy in San Francisco (Adams et al. 2017). For working-age adults, there are many opportunities to expand interprofessional practice. These opportunities should focus on locations frequented by working adults, such as worksites, grocery stores or pharmacies, or other settings where medical or oral health care is delivered.