Supplemental Material for: Caries Experience in Children and Adolescents with Thalassemia: A Systematic Review and Meta-analysis.

Five databases were searched from January 2000 to January 2026 for cross-sectional and case-control studies in individuals aged ≤18 years with any thalassemia type. Risk of bias was appraised using the Newcastle-Ottawa Scale and JBI Checklist. Pooled mean differences (MD) with 95% confidence intervals (CIs) were derived using random-effects models, and certainty of evidence was graded using GRADE.</p><p dir="ltr"><b><i>Results</i></b></p><p dir="ltr">22 studies from 12 countries were included; most involved transfusion-dependent children and adolescents with β-thalassemia major and 13 contributed quantitative data.

Children with thalassemia had significantly higher caries experience in both permanent dentition (10 studies; n = 1,646; MD = 1.41, 95% CI: 0.36 - 2.45) and primary dentition (6 studies; n = 1,256; MD = 1.59, 95% CI: 0.39 - 2.79). However, heterogeneity was very high across both outcomes, publication bias was substantial, with trim-and-fill adjustment rendering the permanent dentition estimate non-significant and GRADE certainty was rated very low.</p><p dir="ltr"><b><i>Conclusion</i></b></p><p dir="ltr">Unadjusted analyses indicated higher mean DMFT and dmft among children and adolescents with thalassemia; however, prediction intervals crossed zero, and substantial heterogeneity and possible reporting bias, including small-study effects, limit confidence in the stability of the observed effect.

The certainty of evidence was very low, precluding a stable estimate of the magnitude of the association. Most evidence concerned transfusion-dependent children and adolescents with β-thalassemia major, limiting the generalizability of findings to other forms of thalassemia. Preventive dental care remains justified on clinical and mechanistic grounds, despite the uncertainty in the quantitative evidence.</p>