Dimorphism in Dental Tissues: Sex differences in Archaeological Individuals for Multiple Tooth Types

Abstract

ObjectivesDimorphism in the dentition has been observed in human populations worldwide. However, research has largely focused on traditional linear crown measurements. As imaging systems, such as micro-computed tomography (micro-CT), become increasingly more accessible, new dental measurements such as dental tissue size and proportions can be obtained. This research investigates the variation of dental tissues and proportions by sex in archaeological samples.Materials and MethodsUpper and lower first incisor to second premolar tooth rows were obtained from 30 individuals (n=300), from 3 archaeological samples. The teeth were micro-CT scanned and surface area and volumetric measurements were obtained from the surface meshes extracted. Dental wear was also recorded and differences between sexes determined.ResultsEnamel and crown measurements were found to be larger in females. Conversely, dentine and root measurements were larger in males.DiscussionThe findings support the potential use of dental tissues to estimate sex of individuals from archaeological samples, whilst also indicating that individuals aged using current dental ageing methods may be under- or over-aged due to sex differences in enamel thickness.

Male Cayo Santiago rhesus macaques (Macaca mulatta) tend to have greater molar wear than females at comparable ages: Exploring two possible reasons why

“…In humans, when sex differences in dental wear have been found, it is usually the case that males exhibit greater wear and/or wear rates than females, in both modern (e.g., Cunha‐Cruz et al, 2010; Hugoson et al, 1988; Johansson, 1992; Knight et al, 1997; Molnar et al, 1983; Tomenchuk & Mayhall, 1979) and ancient population samples (e.g., Fernée et al, 2021; Kaifu, 1998; Masotti et al, 2017). Sex differences in molar wear have been attributed to a variety of factors, including sex differences in dietary abrasiveness (Masotti et al, 2017; Molnar et al, 1983), male‐biased bruxism (Tomenchuk & Mayhall, 1979), and greater enamel thickness in females relative to males (Fernée et al, 2021).…”

“…In humans, when sex differences in dental wear have been found, it is usually the case that males exhibit greater wear and/or wear rates than females, in both modern (e.g., Cunha‐Cruz et al, 2010; Hugoson et al, 1988; Johansson, 1992; Knight et al, 1997; Molnar et al, 1983; Tomenchuk & Mayhall, 1979) and ancient population samples (e.g., Fernée et al, 2021; Kaifu, 1998; Masotti et al, 2017). Sex differences in molar wear have been attributed to a variety of factors, including sex differences in dietary abrasiveness (Masotti et al, 2017; Molnar et al, 1983), male‐biased bruxism (Tomenchuk & Mayhall, 1979), and greater enamel thickness in females relative to males (Fernée et al, 2021). In contrast to what appears to be a tendency for human males to wear their molars more rapidly than human females, Molnar (1971) reported significantly greater wear in the female molars of California Native American skeletal remains relative to those of males, which he argued was in part related to females' greater consumption of abrasive plant foods.…”

“…As molars function to shear, crush, and grind food (Lucas, 2004), sex differences in molar tooth wear may indicate sex differences in diet that are revealing about differential resource use or behavior in the past (e.g., Masotti et al, 2017; Molnar, 1971). The use of dental wear to age human remains requires attention to sex, as sex differences in dental wear can complicate age at death estimates (Fernée et al, 2021).…”

A review of advances in tribology in 2020–2021

“…In addition to dental implants, tribological problems in other dental appliances also existed, including archwires and brackets [738], etc. Other interesting applications in oral tribology included evolution and archaeological studies [739].…”

Sexual dimorphism in deciduous tooth crown size: Variability within and between groups

“…Continuing study of permanent dental dimorphism confirms that in crown size males exceed females in mean MD, BL, crown height and crown area, and that the most sexual dimorphic permanent teeth are the canines and the least dimorphic are the incisors. Intergroup variation in sexual dimorphism of permanent tooth crown size (Brace & Ryan, 1980) have been augmented by documentation of dimorphism in dental tissues (Fernee et al, 2021; Schwartz & Dean, 2005), investigation of the differential influence of sex hormones and sex chromosomes on dimorphism in tooth crown size (Guatelli‐Steinberg et al, 2008: Ribeiro et al, 2012), and attribution of sex in unidentified individuals in Nepal (Acharya & Mainali, 2007).…”