Trends in the Burden of Untreated Caries of Permanent Teeth in China, 1993-2017: An Age-Period-Cohort Modeling Study

Introduction: This study aims to identify the trends in incidence and prevalence of untreated caries in permanent teeth in China during 1993-2017.

Methods: Data representing >31 billion person-years of observation from the Global Burden of Disease study 2017 were analyzed. Age-period-cohort modeling was performed to investigate the trends in untreated caries that may be of value to policymakers. Analyses were conducted in 2019-2020.

Results: Prevalence of untreated caries in permanent teeth decreased steadily before 2010; after which, an increasing trend was noted without the signs of plateauing (age-adjusted annual percentage change, 1993-2017: -0.54%, 95% CI= -0.75%, -0.33%; declining period RR, 1993-2017: p=6.33 × 10^-9; declining cohort RR, 1993-2017: p=3.46 × 10^-6). Although untreated caries prevalence declined overall among multiple age groups (p<0.05), an increase in prevalence after 2010 was noted. This was driven by the deteriorating oral health condition in recent birth cohorts aged <25 years. Estimates of the longitudinal age trend (incidence: -0.013, 95% CI= -0.015, -0.011; prevalence: -0.0038, 95% CI= -0.0060, -0.0015) suggested that the highest untreated caries incidence and prevalence rate were both observed among young adults aged 20-24 years. No differences between incidence and prevalence of untreated caries were observed among adults aged >55 years (p>0.05).

Conclusions: The increased burden of untreated caries in China after 2010 is driven by those aged <25 years. Untreated caries data from the Global Burden of Disease study are a valid complement to the data from the Chinese National Oral Health Epidemiology Surveys.