Sexual dimorphism of dental tissues in modern human mandibular molars.

Abstract

Previous studies have revealed that human permanent dental tissue proportions differ significantly between males and females, with females having relatively thicker enamel relative to overall crown area than males. The aims of this study are to investigate sexual dimorphism in permanent mandibular molars and to determine whether such differences can be used to estimate sex in modern humans reliably. The permanent mandibular molars used in this study (n = 51) originate from 36 individuals of known sex from a Spanish anthropological collection. Eight variables were assessed from two-dimensional (2D) mesial planes of section obtained from microtomographic scans. Binary stepwise logistic regression was then applied to the data. Male molars possess significantly greater quantities of dentine than females, both absolutely and proportionally. Females differed significantly from males by having greater relative enamel thickness. Logistic regression identified the proportion of dentine (relative dentine area [RDA]) as the most important sex discriminator, which can be used to correctly classify specimens with an overall accuracy rate of 74.36%. These results confirm that sexual dimorphism in mandibular molar size is a result of males having a greater amount of dentine, both absolutely and proportionally. The findings suggest that 2D measurements of RDA may be useful for sex determination, although further research is required to test the reliability of these predictive techniques across different populations.