Association of obesity with the eruption of first and second permanent molars in children: a systematic review

Background Eruption timing of permanent teeth, particularly first and second molars, is of great importance due to its influence on occlusion, caries risk and timing of preventive and orthodontic intervention. Aim To evaluate the evidence assessing the correlation between obesity and eruption time of first and second permanent molars in children under 16 years of age as compared to normal-weight children. A secondary aim was to assess the total number of erupted teeth in both groups. Methods A systematic search of databases including PubMed, MEDLINE, EMBASE, Scopus and Web of Science was conducted. Studies that assessed the effect of body mass index (BMI), adjusted BMI or z scores on dental eruption were included. National Institute of Health 'Quality Assessment Tool for Observational Cohort and Cross-sectional Studies' was used to assess the quality of included papers. A random-effects model with its 95% confidence intervals (CIs) was considered for meta-analysis. Results A total of 381 papers were screened following duplicate removal. Twenty-six papers were read in full text, of which 19 were excluded. Seven studies were included in this review; one was longitudinal, and six were cross-sectional in design. A positive association of dental eruption with obesity was noted in six studies. Two studies were included in the explorative meta-analysis, the results of which indicated that obese, 12-year-olds are likely to have one more erupted tooth than their counterparts with a mean difference (MD) of (0.99, 95% CI 0.628-1.352). Conclusion There appears to be a positive correlation between obesity and dental eruption including the eruption timing of first and second permanent molars. Main risk of bias arises from the cross-sectional nature of included studies and lack of control of potential confounders. Further high-quality evidence is required to elucidate this association. Registration PROSPERO (CRD42017084368). Registration PROSPERO (CRD42017084368).