Mental Foramen and Anterior Loop Anatomic Characteristics: A Systematic Review and Meta-analysis of Cross-sectional Imaging Studies.

Abstract Introduction The present study aimed to review the epidemiologic, topographic, and morphometric aspects of the mental foramen (MF) and anterior loop (AL) on cone-beam computed tomographic imaging studies. Methods An International Prospective Register of Systematic Reviews (PROSPERO)-registered systematic review (CRD42018112991) was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Two reviewers independently performed data extraction from observational studies that evaluated MF and AL on 7 electronic databases. MedCalc (MedCalc Software bv, Ostend, Belgium) software was used to perform a meta-analysis with a 95% confidence level. Results Of 1545 articles, 66 met the inclusion criteria, totaling 14,233 patients from 5 continents, with a total of 6655 females and 5884 males (some studies did not report sex), with an age range between 8 and 89 years. The most prevalent shapes of MF were oval (48.72%) and circular (44.36%), and the most frequent horizontal positions were between premolars (43.66%) and in line with the long axis of the second premolar (43.12%). Conclusions Based on the articles that assessed AL, the mean prevalence was 43.18%, with most studies reporting bilateral localization as the most prevalent.