Global Trends and Epidemiological and Demographic Drivers of Caries Incidence

Objectives: Epidemiological studies of caries burden have traditionally utilized measures of lifetime caries prevalence such as DMFT. In contrast, measures of untreated caries provide a more direct measure of the prevailing burden of caries among a population. Compared to the measure of prevalence, caries incidence is particularly suitable for monitoring trends of caries burden in that it is unaffected by changes in treatment rate among a population. We aimed to investigate incidence of untreated caries in permanent teeth worldwide during 1990-2019 and to explore drivers of the evolving caries burden.
Methods: The number and age-standardized incidence rate of untreated caries in permanent teeth were extracted from the Global Burden of Disease Study 2019. Percentage changes in age-standardized incidence rate between 1990 and 2019 were calculated globally and by world super-region. Differences in the number of incident caries cases between 1990 and 2019 were further decomposed into demographic and epidemiological components.
Results: Globally, there were 3.1 billion (95% Uncertainty Interval: 2.8-3.4 billion) incident cases of untreated caries in permanent teeth in 2019. The global age-standardized incidence rate was 39200.4 (34905.2-43168.3) per 100000 person-years in 2019, with the highest incidence rate in South Asia (40545.0, 36132.2-44337.6). The largest increase in age-standardized incidence rate was noted in Central European, Eastern Europe, and Central Asia (1.5%, 0.2%-2.8%). Globally, the contribution of population growth, shift in age-structure, and change in age-specific rate to the increased caries incident cases was 49.6%, -2.1%, and 0.5% of the incident cases in 1990, respectively. In Sub-Saharan Africa, the contribution by population growth was 128.9%.
Conclusions: Burden of caries remains substantial globally with distinct regional heterogeneity. Demographic forces are poised to heighten the global number of caries incident cases unless progress in reducing burden of caries is substantially accelerated.