Over two hundred million injuries to anterior teeth attributable to large overjet: a meta-analysis

Background/Aim: The association between large overjet and traumatic dental injuries (TDIs) to anterior teeth is documented. However, observational studies are discrepant and generalizability (i.e. external validity) of meta-analyses is limited. Therefore, this meta-analysis sought to reconcile such discrepancies seeking to provide reliable risk estimates which could be generalizable at global level. Material and Methods: Literature search (years 1990–2014) was performed (Scopus, GOOGLE Scholar, Medline). Selected primary studies were divided into subsets: ‘primary teeth, overjet threshold 3–4 mm’ (Primary3); ‘permanent teeth, overjet threshold 3–4 mm’ (Permanent3); ‘permanent teeth, overjet threshold 6 1 mm’ (Permanent6). The adjusted odds ratios (ORs) were extracted. To obtain the highest level of reliability (i.e. internal validity), the pooled OR estimates were assessed accounting for between-study heterogeneity, publication bias and confounding. Result robustness was investigated with sensitivity and subgroup analyses. Results: Fifty-four primary studies from Africa, America, Asia and Europe were included. The sampled individuals were children, adolescents and adults. Overall, there were >10 000 patients with TDI. The pooled OR estimates resulted 2.31 (95% confidence interval – 95CI, 1.01–5.27), 2.01 (95CI, 1.39–2.91) and 2.24 (95CI, 1.56– 3.21) for Primary3, Permanent3 and Permant6, respectively. Sensitivity and subgroup analyses corroborated these estimates. Conclusions: Reliability and generalizability of pooled ORs were high enough and made it possible to assess that the fraction of global TDIs attributable to large overjet is 21.8% (95CI, 9.7–34.5%) and that large overjet is co-responsible for 235 008 000 global TDI cases (95CI, 104,760,000-372,168,000). This high global burden of TDI suggests that preventive measures must be implemented in patients with large overjet.