Enamel growth rates of anterior teeth in males and females from modern and ancient British populations

Abstract

Objective This study explored biological sex differences in the regional daily growth rates of human anterior enamel from modern and ancient populations in Britain. Methods Maxillary permanent incisors (n = 80) and canines (n = 69) from Roman, Anglo‐Saxon, Medieval, and Modern day populations were analyzed using histological methods. Daily secretion rates (DSRs) were collected for inner, mid, and outer regions of cuspal and lateral enamel. Modern day samples were of known sex, archeological individuals had sex determined using standard osteological methods. Variation in DSRs between the sexes, both between and within populations, was sought using parametric and nonparametric tests. Results When all samples were pooled, there was no significant difference between males and females. Similarly no significant differences in DSRs were identified between male and females within each population. When DSRs were compared between the populations, DSRs decreased from the more ancient to the more recent populations for males, and for females. More interpopulation differences were observed in males. Discussion This study presents evidence for the relative consistency of enamel DSRs between male and female groups within each British population. Interpopulation analyses found DSRs slowed significantly between Roman and modern day populations for both sexes, with male DSRs showing the greatest variation between populations.

Growth rates of accessory human enamel: a histological case study of a modern-day incisor from Northern England

“…The DSRs for the incisors were calculated for the inner, mid, and outer areas of the lateral and cuspal enamel sites of each tooth using standard methods (e.g. Beynon et al, 1991a;Schwartz et al, 2001;Mahoney, 2008;Aris et al, 2020aAris et al, , 2020b. Each region within the cuspal and lateral sites was determined by dividing the length of the enamel regions into three equidistant portions, following the longitudinal axis of local enamel prisms (Figure 2).…”

“…For the standard incisor sample these results were then similarly divided to give a grand mean and standard deviation, following the standard statistical and methodological approaches of studying human enamel growth rates (e.g. Beynon et al, 1991Beynon et al, 1998Reid et al, 1998;Lacruz & Bromage, 2006;Mahoney, 2008;Aris et al, 2020aAris et al, , 2020b. For S197 the six mean DSRs for each region were kept separate for future analysis.…”

“…These rates accelerate from inner enamel regions proximal to the enamel dentine junction towards the outer enamel surface (e.g. Beynon et al, 1991Beynon et al, 1998Reid et al, 1998;Lacruz & Bromage, 2006;Mahoney, 2008;Aris et al, 2020aAris et al, , 2020b). Daily secretion rates are also faster relative to their proximity to the dentine horn (Beynon et al, 1991).…”

“…Analysis of DSRs for human samples have examined variations within individual teeth (Mahoney, 2008), differences between biologically male and female groups (Schwartz et al, 2001), and more recently variations between populations (Aris et al, 2020a(Aris et al, , 2020b. Despite the breadth of these studies, they have universally used teeth absent of evidence of stress, pathology, and accessory enamel growth.…”

“…Schwartz et al, 2001), and between populations (e.g. Smith et al, 2007;Aris et al, 2020aAris et al, , 2020b. A common trend between these lines of research is the exclusive use of what are deemed as dental samples containing no evidence of pathology, stress markers, or growth of accessory enamel (defined here as: growth of enamel outside of the features typically used to define and identify human tooth types).…”