Dental tissue proportions of European and African populations: sexual dimorphism

Accurate sex estimation is an essential step for the reconstruction of the biological profile of the human remains. Previous research showed that elements of the human permanent dentition are sexually dimorphic. The aim of the present study is to assess the dental tissue proportions of modern human permanent mandibular canines, in order to identify the sexual variability present in two populations from different geographical origin. Our sample consisted of a total of 53 mandibular permanent canines of known sex from Europe and Africa. Bucco-lingual sections of the crown were obtained and the different metrics described by Martin (1983) were recorded using the methodology devised for canine teeth by Feeney and colleagues (2010). Our results corroborate that sexual dimorphism in dental tissues proportions is due to males having an absolute greater amount of dentine, as well as females having a relative greater and thicker enamel cap area, which is hidden behind the crown size differences between males and females. The histological patterns differ depending on the ancestry of the individual, although the sexual dimorphism of both populations separately is similar to those of the whole sample. The coronal dentine and pulp area was relatively greater in the European sample, as well as a larger relative EDJ length. However, African population had, absolutely and relatively, greater enamel cap area. This study results support that sexual dimorphism of dental size is mainly due to male’s greater amount of dentine, whereas enamel differences not making a large contribution to overall tooth size dimorphism. Moreover, the geographical origin of the individuals in the sample should be a factor to take into account in the assessment of the sexual dimorphism from histological patterns.