Background This report is limited to clinical studies on humans and to the treatment of children and adolescents. Treatment that includes orthognathic surgery (surgical treatment of severe malocclusions) has been excluded. All types of studies, quantitative as well as qualitatatve, that concern assessment of the risks of no treatment and different aspects of treatment decisions were included.

• When the patient has a large overjet and the upper lip does not protect the front teeth, the incidence of trauma to the anterior teeth of the maxilla is higher (limited scientific evidence).
• If the maxillary canines are incorrectly positioned in the jawbone before their eruption, the risk that they will damage the roots of the front teeth as they emerge increases (ectopic eruption) (limited scientific evidence).
• The prevalence of caries in people with occlusal deviations is the same as in those whose bite is normal (limited scientific evidence).
• A correlation between moderate malocclusions and negative effects on the self-image of 11–14-year-olds has not been found (limited scientific evidence).
• Adults with untreated malocclusions express more dissatisfaction with the appearance of their bite than adults without malocclusions (limited scientific evidence).
• Scientific evidence is insufficient for conclusions on a correlation between specific untreated malocclusions and symptomatic temporomandibular joint disorders.

Consequences of Untreated Malocclusions

Priority Indices for Orthodontic Treatment

• Scientific evidence for conclusions concerning the validity (that is, if a tool measures what it is intended to measure) of morphological priority indices (indices based on deviations in the bite and the dental arch from an established norm) are lacking.
• Scientific evidence is insufficient for conclusions concerning the validity of esthetic indices from a societal perspective.

The Decision to Undergo Orthodontic Treatment

• Orthodontic treatment is initiated in most cases by the general dental practitioner.
• The appearance of the teeth is the patients’ most important reason for seeking orthodontic treatment.

Morphologic Stability and Patient Satisfaction 5 years or more after Orthodontic Treatment

• Treatment of crowding aligns the dental arch. However, the length and width of the mandibular dental arch gradually shorten in the long term, and crowding of the anterior teeth can reoccur. This condition cannot be predicted at the individual level (limited scientific evidence).
• Treatment of large overjet with fixed appliances according to Herbst (braces that hold the mandible in a forward position via a telescoping mechanism) normalizes the occlusion. Relapses occur, but cannot be predicted at the individual level (limited scientific evidence).
• Scientific evidence is insufficient for conclusions on stability after treatment of other morphological discrepancies.
• Scientific evidence is insufficient for conclusions on patient satisfaction in the long term (at least 5 years) after the conclusion of orthodontic treatment.

Risks and Complications of Orthodontic Treatment

• Orthodontic treatment with fixed appliances, as well as the application of separators and new arch wires, is painful in the beginning (moderately strong scientific evidence).
• Orthodontic treatment can cause a reduction of the bone level between the teeth; the scope of this reduction, however, is so small that it lacks clinical relevance (moderately strong scientific evidence).
• Stainless steel wires that were attached to the back of the anterior teeth of the mandible by etching (retainer) have not been found to give rise to caries in a 5-year perspective (limited scientific evidence).
• Orthodontic treatment with fixed appliances that contain nickel have not been found to increase the incidence of nickel sensitivity (limited scientific evidence).
• Root resorptions (gradual dissolution of tooth roots) up to one-third of the length of the root occur in 11–28 percent of the patients who have undergone orthodontic treatment (limited scientific evidence). Information on the long-term consequences of this is lacking.
• Teeth with incomplete root development are resorbed to a lesser degree than fully developed teeth (limited scientific evidence).
• Side effects such as temporomandibular joint disorders (TMD) have not been demonstrated in connection with orthodontic treatment (limited scientific evidence).
• Scientific evidence is insufficient for conclusions on what effect a suspension of treatment has on root resorptions during ongoing orthodontic treatment.

SBU’s Review of Praxis

• The share of orthodontic treatments that were begun per age group was on average 27 percent and varied between 21 percent and 39 percent for 20 of 21 county councils. The number of specialists per 10,000 children was on average 1.12 and varied between 0.82 and 1.68.