Abstract
<title>Abstract</title> <p> <bold>Background.</bold> Oral disease is common in athletes, and two prior meta-analyses have estimated its prevalence. Neither pooled a controlled comparison, so the central epidemiological question — whether athletes and habitually active people carry more oral disease than comparable less-active people, and if so which disease — has not been quantitatively answered. Erosive tooth wear and dental caries have different causal pathways, and there is reason to expect exercise to affect them differently. <bold>Methods.</bold> This review was conducted and reported in accordance with PRISMA 2020. Federated bibliographic searching (PubMed/MEDLINE, Scopus, Semantic Scholar) and citation chasing of prior reviews identified observational studies comparing erosive tooth wear or dental caries between an athlete or habitually active group and a non-athlete or lower-activity comparison group. Effects were expressed as odds ratios and pooled using random-effects models with restricted maximum likelihood estimation of between-study variance and the Hartung–Knapp–Sidik–Jonkman variance correction. Prediction intervals, leave-one-out diagnostics, risk-of-bias appraisal and GRADE certainty ratings were computed. Tests for funnel-plot asymmetry were pre-specified but withheld because fewer than 10 studies contributed to each analysis. <bold>Results.</bold> Six studies (1,042 participants) met the eligibility criteria. Erosive tooth wear was substantially more likely in active and athlete groups than in comparison groups (k = 4, N = 545; pooled OR 5.58 (95% CI 2.22 to 14.00); t(3) = 5.95, p = 0.009). Heterogeneity was modest (Q(3) = 5.61, p = 0.132; I² = 47%; REML τ² = 0.000) and the 95% prediction interval (1.61 to 19.34) excluded the null. The pooled estimate was robust to omission of any single study (range 4.41 to 5.94). By contrast, dental caries showed no clear association (k = 3, N = 315; pooled OR 1.71 (95% CI 0.61 to 4.75); t(2) = 2.26, p = 0.153; I² = 6%). <bold>Conclusions.</bold> Habitual physical activity and athletic participation are associated with a large increase in the odds of erosive tooth wear, but not with a clear increase in dental caries. This dissociation is consistent with an exposure that is chemical and exercise-linked — frequent acidic fluid intake against transiently reduced salivary flow — rather than one acting through the bacterial-fermentation pathway. Certainty was rated LOW for erosion and VERY LOW for caries; the estimates should guide screening priorities and further research rather than serve as definitive risk figures. <bold>Registration.</bold> This review was not prospectively registered. The absence of registration is disclosed as a limitation (§5.5). </p>