Changes in mandibular dimensions during the mediaeval to post-mediaeval transition in London: A possible response to decreased masticatory load.

Abstract: Objectives: Biomechanical forces, such as those produced during mastication, are considered a primary agent in stimulating craniofacial growth and development. There appears to be a strong connection between the strength of the masticatory muscles and the dimensions of the craniofacial complex, with changes in biomechanical force and muscular strength influencing and altering the underlying bony tissues. This is markedly apparent in the mandible and it is possible to infer that changes to mandibular form are due in part to dietary changes. This study aims to investigate this idea by using an archaeological sample from a period that experienced important dietary changes as a result of the Industrial Revolution. Design: 279 skeletons from the mediaeval and post-mediaeval periods in London were selected for analysis, and a detailed metric examination of each mandible was carried out. Results: Males and females were analysed separately and statistically significant reductions were observed in nearly all post-mediaeval measurements. This effect was most pronounced in the areas of the mandible associated with masticatory muscles attachment, including the gonial angle, ramus height and width, bi-gonial breadth and bi-condylar breadth. Conclusions: These recorded changes in mandibular morphology of mediaeval and post-mediaeval Londoners are most likely the result of a shift in diet (and associated decrease in masticatory function) observed in the period surrounding the Industrial Revolution. [Copyright &y& Elsevier]