Human behaviour and the temporomandibular joint.
Doctoral thesis, UCL (University College London).
Temporomandibular joint disorders (TMD), an umbrella term referring to a group of orofacial pain disorders, including disc displacement and osteoarthritis, affect a significant portion of the general population, with prevalence of temporomandibular joint osteoarthritis (TMJ OA) at around 30%. The temporomandibular joint (TMJ) is intimately linked to mastication (and as such, diet), with research on animals and modern clinical studies suggesting that disorders of the TMJ may be connected to soft dietary composition and associated with a reduction of the craniofacial complex. Over the past 100,000 years, the size and shape of the human face has undergone marked changes, from large and robust, to relatively small and gracile. Concordantly, human diet has changed profoundly, first in the transition from hunter-gathering to agriculture, then again in the shift to the post-industrialised diet, markedly affecting the rate of caries and malocclusions, which have increased, and dental wear, the severity of which has notably decreased. The question remains as to whether these dietary shifts, particularly modernisation, have had an effect on the temporomandibular joint. This work aims to combine archaeological, evolutionary and clinical perspectives to provide a comprehensive understanding of the impact changes in human behaviour (primarily those related to diet) have had on the prevalence and distribution of temporomandibular joint disorders, specifically osteoarthritis. Three different skeletal populations (modern Americans, Medieval and post-Medieval Londoners and Prehistoric Native Americans) were examined for the severity of tooth wear, presence of TMJ osteoarthritis, morphology of the TMJ and tooth loss, as well as undergoing a metric and geometric morphometric analysis. The results suggest that differing patterns of subsistence can impact the distribution and frequency of TMJ OA, with rates of OA highest in the contemporary populations, this seeming to contradict previous archaeological theories on TMJ OA, which typically associated high levels of OA with heavy tooth wear and using the teeth as tools. The results of this research also suggest that different methodological approaches need to be used when analyzing TMJ OA, utilising diagnostic techniques that are more clinically relevant, in part due to the unique and complex nature of the TM joint.
|Title:||Human behaviour and the temporomandibular joint|
|Additional information:||Permission for digitisation not received|
|UCL classification:||UCL > School of Arts and Social Sciences > Faculty of Social and Historical Sciences > Institute of Archaeology|
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