Sexual dimorphism analysis in permanent human mandibular canines by geometric morphometrics

Sex estimation of unknown human remains is a common form of assessment in bioarchaeological and forensic practice. When remains are poorly preserved, teeth become important. Research regarding the use of teeth for sex estimation mainly uses odontometrics. Nevertheless, to date, few studies have aimed to systematically evaluate sexual dimorphism in tooth shape. The purpose of this study is to analyze and describe sexual dimorphism in the mandibular canine. Landmarks and semilandmarks were placed on the occlusal, mesiodistal and buccolingual views of mandibular canines of 56 individuals (37 males and 19 females) from the “Prof. Dr. Rómulo Lambre” collection. Moreover, the impact of dental wear in morphometric analyses on sexual dimorphism was explored. The shape of male and female canines differed significantly in the three views analyzed. Female canines showed a larger crown in relation to its root, while male canines showed greater roots in relation to their crown. While female canines showed a large development of the cingulum, male’s teeth exhibited less development of this trait. For these reasons, this study constitutes a first approach to show the usefulness of shape for estimating the sex of canine teeth. These differences might be the result of dissimilarities in the total amount of dentin and enamel due to the effect of sex-linked genes in the growth of these tissues.