1UCL Institute of Archaeology, University College London, 2Department of Ancient Egypt and Sudan, The British Museum
Thursday 2:30-2:45, Galleria North
The temporomandibular joint (TMJ) is intimately linked to mastication (and as such, diet), with research on animals and modern clinical studies suggesting that temporomandibular joint osteoarthritis (TMJ OA) may be connected to soft dietary composition and associated with reduction in the craniofacial complex. Over the past 100,000 years, the form of the human face has undergone marked changes, from large and robust, to relatively small and gracile. Concordantly, human diet changed profoundly; first in transitioning from hunter-gathering to agriculture, then again in the shift to the post-industrialised diet. This has markedly increased the rate of caries and malocclusions, while the severity of dental wear has notably decreased. The question remains as to whether these dietary shifts, particularly modernisation, have impacted the temporomandibular joint, specifically TMJ OA.
Three assemblages with distinct dietary patterns (a modern documented collection, Medieval and post-Medieval Londoners, and Prehistoric Native Americans) were examined for the severity of tooth wear, presence of TMJ OA, morphology of the TMJ, and cranial metrics. TMJ OA prevalence was as follows: Prehistoric Native Americans 10.6%; Medieval 13.3%; post-Medieval 29.5%; modern documented 30.2%. The results suggest that differing patterns of subsistence can impact the distribution and frequency of TMJ OA, with OA highest in the contemporary assemblages; this is concurrent with a decrease in tooth wear severity and a reduction in mandibular size. The increase in TMJ OA is likely the result of a change in the functional biomechanics of the joint, creating a less stable and more disease-prone environment.