Association Between Body Mass Index and Dental Caries Severity in Adults: A Systematic Review and Meta-Analysis.

INTRODUCTION AND AIMS: While the association between body mass index (BMI) and dental caries in adults is debated, prior meta-analyses have primarily focused on caries prevalence using dichotomous outcomes. This study offers a novel approach by aiming to quantitatively synthesize the relationship between BMI and the burden of dental caries, using continuous data from the mean DMFT (decayed, missing, and filled teeth) and DT (decayed teeth) indices in adults. METHODS: PubMed, Embase, CINAHL, and Web of Science were searched through March 2025 for observational studies comparing DMFT/DT scores across BMI categories in adults. Methodological quality was assessed using the AHRQ checklist. Data were pooled using random-effects models, with subgroup analyses conducted to explore heterogeneity. Evidence certainty was evaluated using the GRADE framework. RESULTS: Twelve cross-sectional studies (n = 85,975) were included. Obese adults had higher DMFT scores than normal-weight individuals (WMD: 1.75, 95% CI: 0.05-3.46), though statistical significance was lost in sensitivity analysis. A more robust association was found for the combined overweight/obese group (WMD: 1.28, 95% CI: 0.17-2.39). For DT, significant associations emerged only in high-income countries for overweight (WMD: 0.60, 95% CI: 0.39-0.81) and combined overweight/obese categories (WMD: 0.59, 95% CI: 0.40-0.78). No significant associations were identified for underweight individuals. CONCLUSIONS: Our findings provide quantitative evidence for associations between excess body weight and cumulative dental caries burden in adults. The observed heterogeneity and low evidence certainty, particularly the influence of national income levels, highlight the complexity of this association and underscore the need for cautious interpretation. CLINICAL RELEVANCE: Findings support considering oral health in obesity management. Clinicians should recognize that excess body weight may indicate not just a higher risk of having caries, but a greater severity of the disease burden.