Increased Prevalence of Generalized Joint Hypermobility Observed in Patients With Recurrent Temporomandibular Joint Dislocation.

BACKGROUND: Generalized joint hypermobility (GJH), determined by the Beighton score, is a fundamental part of diagnosing benign joint hypermobility syndrome (BJHS), which may also present extra-articular manifestations, and is determined by the Brighton criteria. PURPOSE: This study was designed to investigate whether there is an association between recurrent temporomandibular joint (TMJ) dislocation and these disorders. STUDY DESIGN, SETTING, AND SAMPLE: A retrospective cross-sectional study was conducted. Hospital-based patients with a history of recurrent TMJ dislocation were compared to population-based patients that did not experience TMJ dislocations or any other TMJ disorders. Age and sex matching were performed between the study groups. All subjects reached the age of skeletal maturity. PREDICTOR VARIABLE: A history of recurrent TMJ dislocations. MAIN OUTCOME VARIABLES: Measurements of Beighton score (range from 0 to 9 with a score of ≥ 4 indicating GJH) and correspondence to the Brighton criteria (with at least two "major" criteria or one "major" criterion plus two "minor" criteria or four "minor" criteria indicating BJHS). COVARIATES: Included age and sex. ANALYSES: Mann-Whitney U-test for continuous variables and the χ2 test or Fisher's exact test for categorical variables. Statistical significance was set at P < .05. RESULTS: A total of 68 participants were included, of whom 34 patients presented with recurrent TMJ dislocations compared with a control population of 34. The Mean participants were 31.35 ± 8.06 years, and 29.4% (n = 20) were males. Of the dislocation group, 16 (47.0%) patients had a Beighton score of 4 or higher. The Beighton sum score was significantly higher, with a TMJ dislocation group mean score of 3.06 ± 2.8, compared with a control score of 0.82 ± 1.1 (P = .001). A total of 58.8% (n = 20) of the TMJ dislocation group participants met the Brighton criteria versus none (0.0%) of the control group (P = .001). CONCLUSION: We found an association between recurrent TMJ dislocation and GJH. An association with BJHS was also found, based mainly on articular manifestations. Early detection of these disorders in patients suffering from recurrent TMJ dislocation may help identify individuals at increased risk for joint instabilities and allow the implementation of appropriate preventive management strategies.

Are There Cephalometric Measurements Associated With Recurrent Temporomandibular Joint Dislocation?

PURPOSE: 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. METHODS: 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. RESULTS: 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 (4.56o ± 5.7o vs 9.60o ± 3.9o; P = .007), Y-axis (58.01o ± 4.9o vs 61.72o ± 3.3o; P = .019), and Frankfurt mandibular plane (24.10o ± 6.1o vs 30.14o ± 4.7o; P = .004). CONCLUSIONS: 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.

The influence of mandibular condyle morphology on TMJ anterior dislocations.

OBJECTIVES: The present study was designed to investigate the correlation between the bony morphology of the mandibular condyle and the occurrence of temporomandibular joint (TMJ) idiopathic anterior dislocation. STUDY DESIGN: A comparative retrospective study was conducted among 14 patients presenting idiopathic anterior dislocations (study group) and 15 patients who did not suffer from any TMJ disorders (control group). All patients underwent a multidetector computed tomography scan demonstrating the full extent of their joints. The scans of 58 joints were reconstructed and analyzed by tools available in Dolphine3 software. Mandibular condyle size and volume were measured, and its shape was characterized. RESULTS: Shape, width, length, height, and volume of the mandibular condyles did not differ statistically between the study and control groups. CONCLUSION: Mandibular condyle morphology does not affect TMJ idiopathic anterior dislocation.

The influence of articular eminence morphology on temporomandibular joint anterior dislocations.

OBJECTIVE: The aim of this study was to investigate the correlation between the bony morphology of the articular eminence and the occurrence of idiopathic anterior temporomandibular joint (TMJ) dislocation. STUDY DESIGN: A comparative retrospective study was conducted in 14 patients with idiopathic anterior dislocations (study group) and 14 patients who did not suffer from any TMJ disorders (control group). All patients underwent multidetector computed tomography (MDCT), which demonstrated the full extent of their joints. The scans of 56 joints were reconstructed and analyzed by using the tools available in Dolphin 3 software. Gross morphology characteristics and fine morphologic characteristics were defined by measuring the articular eminence inclination and height on the lateral, middle, and medial aspects of the articular eminence. RESULTS: Gross and fine morphologic characteristics of the articular eminence did not differ statistically between the study group and the control group. CONCLUSIONS: Articular eminence morphology does not affect TMJ idiopathic anterior dislocation.