The influence of age, sex, population group, and dentition on the mandibular angle as measured on a South African sample

Abstract

The mandibular angle is measured in physical anthropological assessments of human remains to possibly assist with the determination of sex and population affinity. The purpose of this investigation was to establish how the mandibular angle changes with age and loss of teeth among the sexes in South African population groups. The angles of 653 dried adult mandibles from the Pretoria Bone Collection were measured with a mandibulometer. Males and females of both South African whites and blacks were included. To compensate for imbalances in numbers among subgroups, type IV ANOVA testing was applied. No association was found between age and angle within either of the populations, within sexes, or within dentition groups. The angle was the most obtuse in individuals without molars and with an uneven distribution of molars, and most acute in the group with an even distribution of molars on both sides. Statistically significant differences (P < 0.001) were found in the angle between the two population groups and sexes in the overall sample as well as in the subgroup with absent molar teeth (P = 0.003 for sex, males more acute angle, and P = 0.001 for population group, blacks more acute angle), although a very large overlap existed. No significant differences could be demonstrated between the sexes or populations within the subgroups with molars. We concluded that the loss of molars, especially if complete or uneven, has a considerable effect on the mandibular angle. In the assessment of human remains, the mandibular angle is not very usable in determining sex.

Investigations Into Age‐related Changes in the Human Mandible,

“…Most studies suggest that antemortem tooth loss is associated with a widening of the gonial angle . Additionally, some have found little to no relationship between gonial angle and age .…”

“…Most studies suggest that antemortem tooth loss is associated with a widening of the gonial angle . Additionally, some have found little to no relationship between gonial angle and age . Ceylan et al found no significant differences in gonial angle between completely edentulous individuals and individuals with unilateral tooth loss in the posterior region, although no completely dentate group was included for comparison.…”

Importance of teeth in maintaining the morphology of the adult mandible in humans

“…The ramus of the mandible in edentulous individuals also appears to be in a reclined position. The overall increase in the MAN_ANG with molar tooth loss has been previously attributed to the so‐called ‘moulding effect’ of the masticatory muscles on the mandibular morphology in an attempt to restore the occlusal plane and maintain optimal mastication . This effect on mandibular morphology is thought to be dependent on the functionality of the masticatory muscles .…”

The Morphometry of the Angle of Mandible and its Correlation with Age and Sex in the eThekwini Metropolitan Region: A Panoramic Study

“…The mandible is the second most durable bone of the body and is the most resilient in unfavourable conditions (Oettlé et al, 2009). The angle of mandible is formed by the tangent lines of the posterior border of the ramus and the base of the mandible (Drake et al, 2010;Leversha et al, 2016).…”