Are There Cephalometric Measurements Associated With Recurrent Temporomandibular Joint Dislocation?

Several theories have been proposed for the etiology of recurrent temporomandibular joint (TMJ) dislocation. The purpose of the present study was to determine whether there are cephalometric measurements associated with this phenomenon.

A retrospective case-control study was performed, which included individuals who suffered from recurrent TMJ dislocation and a control group composed of patients who suffered from unrelated odontogenic infections and did not have any TMJ disorder. All the patients were referred to the Department of Oral and Maxillofacial Surgery at the Hadassah Medical Center between 2010 and 2021 and underwent multidetector computed tomography of the jaws. The main predictor variable was a history of recurrent TMJ dislocations. Covariates included age and gender. The primary outcome variable was a set of 11 cephalometric measurements. A statistical analysis was performed with the Mann-Whitney U-test for continuous variables and the Chi-squared test or Fisher's exact test for categorical variables, followed by a logistic regression model. Multiple comparisons were made by using the Benjamini-Hochberg method.

The total 32 subjects included in the analysis consisted of 16 patients presenting with bilateral recurrent TMJ dislocation and a control population of 16 patients. The mean age was 34.19 ± 12.7 years, 40.6% (n = 13) were males, with no statistically significant differences between the groups. An increased overbite was detected in the TMJ dislocation group, whereas over-jet was greater among the control group, although not statistically significant. Skeletal ratio analysis showed that the TMJ dislocation group had a statistically significantly greater Articulare-Gonion length (46.96 mm ± 5.2 mm vs 43.01 mm ± 5.3 mm; P = .043) and a lower angle of occlusal plane to Frankfort horizontal (4.56^o ± 5.7^o vs 9.60^o ± 3.9^o; P = .007), Y-axis (58.01^o ± 4.9^o vs 61.72^o ± 3.3^o; P = .019), and Frankfurt mandibular plane (24.10^o ± 6.1^o vs 30.14^o ± 4.7^o; P = .004).

Specific cephalometric measurements are associated with recurrent TMJ dislocation. The high Articulare-Gonion length and the low rates of occlusal plane to Frankfort horizontal angle, Y-axis, and Frankfurt mandibular plane found in the study population suggest that the resultant vertically oriented elevator muscles may be considered a predisposing factor for this phenomenon.