Three-dimensional analysis of temporomandibular joint in Chinese adults with normal occlusion and harmonious skeleton

Objective This study aimed to analyze the detailed three-dimensional measurements of temporomandibular joint (TMJ) in Chinese adults with normal occlusion and harmonious skeleton. Methodology In 51 subjects 102 joints were analyzed using Anatomage Invivo dental 5.4. The measurements include: joints' parameters, position, angulation, and inclination of the condyle and articular fossa as well as 3D volumetric of the joint-spaces. All measurements were statistically analyzed by paired Student'sttest to find out the differences between the left- and right sides. Pearson correlation coefficient test was done to figure out the relationship of the TMJ parts in the normal situation. Results The inter-condyle distances medially, geometrically, and laterally were 90.2 +/- 5.2,107 +/- 6.1, and 125 +/- 5.5 mm, respectively. However, the 102 condyles were angulated on three planes 54.9o +/- 11.2, 71.8o +/- 7.3, and 12.5o +/- 6.3 at vertical-, horizontal-, and midsagittal planes, respectively. The joint spaces measurements were 2.6 +/- 0.7 mm, 2.5 +/- 0.8 mm, 2.4 +/- 0.7 mm, and 3.3 +/- 0.7 mm for anterior-, medial-, posterior-, and superior joints, respectively. The total volume of the whole joint-space was 404.3 +/- 71mm(3). The left condyle position was on the centric position whereas the right condyle was eccentric (slightly anterior). Conclusion Chinese subjects are characterized by wide inter-fossa distance and inter-condyle distance; however, no significant correlations with joint spaces in normal occlusion were found. The asymmetries between right- and left mandibular condyle were distinguished in angular and linear-vertical measurements. Finally, this study could be considered as reference data for upcoming research in the Chinese population.