Global Trends in Incidence of Caries in Permanent Teeth of the Elderly Aged Over 55 Years, 1990-2021: A Multilevel Analysis Using GBD Data.

PURPOSE: To examine global, regional, and national trends in the incidence of permanent tooth caries among adults aged ≥ 55 years from 1990 to 2021 and to evaluate disparities across sociodemographic contexts. METHODS AND MATERIALS: Incidence data were obtained from the Global Burden of Diseases 2021 study covering 204 countries and territories. Incidence rates and incident case numbers were analysed at global, regional, and national levels. Temporal trends were assessed using Joinpoint regression to calculate annual percentage change (APC) and average annual percentage change (AAPC). RESULTS: Globally, the number of caries cases in the elderly increased from 121.54 million in 1990 to 260.18 million in 2021, with a relative change of 114%, while the incidence rate slightly decreased from 18.1% in 1990 to 17.5% in 2021. However, there were differences in trends among different age groups, genders, and regions. The 55-59-year-old group had the highest incident rate. Low-to-middle Socio-demographic Index (SDI) areas had a consistently high incidence. The number of cases increased in all Global Burden of Diseases, Injuries, and Risk Factors Study regions. Joinpoint analysis identified significant temporal change points in multiple regions, indicating divergent epidemiological trajectories. CONCLUSION: Permanent tooth caries among adults aged ≥ 55 years continues to represent a significant public health challenge. Although some high-income settings show stabilising trends, increasing incidence in socioeconomically transitioning regions highlights inequalities in preventive coverage and access to care. Targeted, age-specific preventive strategies are essential to address the growing needs of ageing populations.