Changes in mandibular condyle morphology related to tooth wear in a prehistoric human population.

The exact relationship between tooth wear and changes in the shape of the articulating surface of the mandibular condyles is unknown. It is assumed that to some degree these changes are in response to the loads on the joint generated during chewing. Excavated skeletal remains from sites of primitive human habitation provide an opportunity to study the masticatory system of human beings in their natural context, with the features of form and function expressed to their full potential. Accurate measurements of the condylar head can also be made on such remains. A collection of skulls from an excavation site known as Oakhurst on the South African coast provided material for this study. Occlusal wear was measured using the scale devised by Molnar; approximal wear was assessed by measuring the size of the wear facet between the first and second molars. The width of the condyles were measured directly, and a method was devised to measure changes in the proportion of medial and lateral articulating facets. An increase in the size of the lateral facet of the condyle was found to be associated with increased tooth wear. It is suggested that the direction of condylar remodelling may give an indication of the reaction at the joint to optimal mastication.