Investigating Diachronic Changes in the Temporomandibular Joint Surface With a New Approach for Three‐Dimensional Surface Area Measurements

ABSTRACT The temporomandibular joint (TMJ) plays a key role in mastication, and its morphology is influenced by functional loading from biting and chewing. Major dietary shifts in human history, particularly those linked to agricultural and industrial transitions, have substantially reduced masticatory demands. The lowering of the mechanical stress supposedly led to a decrease in the TMJ articular surface area. Although diet‐related effects on craniofacial morphology are well documented, their impact on TMJ size remains poorly understood. A major methodological difficulty lies in defining and measuring the exact areas of the mandibular and temporal articular surfaces. To address this, we applied a 3D color‐mapping filter in MeshLab to mandibular models, enabling the precise delineation and measurement of articular surfaces. This protocol adapted the validated entheses‐based reconstruction of activity (V.E.R.A.) method by Karakostis and Harvati. Our study aimed to assess temporal changes in the condylar surface area of TMJ using this approach. The sample comprised 3D models of 224 adult mandibles from two populations of Polish ancestry: medieval Cedynia (10th–14th century AD ) and early modern Radom (18th–19th century AD ). The color‐mapping filter was used to identify and measure the articular surface. We used the centroid size calculated from 17 landmarks to control for mandibular size variation. The TMJ surface was found to be significantly smaller in the Radom population ( p < 0.001 for females; p = 0.04 for males), also when centroid size was included as a covariate ( p = 0.02). Centroid size did not significantly differ between the groups ( p = 0.18 for females; p = 0.50 for males). The inter‐ and intraobserver measurement errors were nonsignificant. Our findings suggest that reduced masticatory demands, presumably resulting from dietary softening, contribute to the temporal decrease in the TMJ articular surface. The proposed method offers a consistent approach for capturing the exact articular area of mandibular condyles.