Date: March 2021.
Source: Journal of the World Federation of Orthodontists. Vol. 10, Issue 1, 2021, Pages 20-28.
Background: The goal of this study was to determine whether preexisting degenerative temporomandibular joint (TMJ) disorders are associated with hyperdivergent facial phenotype and decreased airway dimensions.
Methods: Cone-beam computed tomography scans of adult female and male individuals, 16 years of age and older, distributed in a case group defined as those with degenerative temporomandibular joint disorder (dTMJD; n = 31) or controls with normal TMJ findings (n = 242) were included. Odds ratios were calculated based on facial type and gender. Analysis of variance was used to compare the airway volume and cross section and mandibular measurements between the groups.
Results: Condylar, ramus, and mandibular heights were significantly smaller in the case group compared with the control group. The odds of having a long face subject was significantly higher (P < 0.00001) in the dTMJD group than in the control group with 81% of the dTMJD subjects versus 11% of the control group having long vertical facial dimensions. The smallest cross-sectional area of the airway of the dTMJD group was significantly narrower (P < 0.0361) compared with the controls. Within the control group, ramus height and mandibular alveolar housing for central incisors were significantly smaller (P < 0.0001; P < 0.007) in the long face subjects. Conclusions: The study shows that a long facial type is associated with findings of degenerative TMJ disorders and related condylar growth disturbances. These degenerative and growth changes may contribute to specific skeletal and dentofacial adaptations resulting in smaller condylar process, mandibular ramus, and body height; thinner alveolar housing at the lower incisor region; and smaller cross-sectional area of the airway.

Article: Association between degenerative temporomandibular joint disorders, vertical facial growth, and airway dimension.
Authors: Amir Dadgar-Yeganeh, David C. Hatcher, Snehlata Oberoi.