Evaluating condylar distraction potential: a comparison between patients with unilateral disc displacement without reduction and asymptomatic volunteers

This study aimed to evaluate and compare the condylar distraction potential and joint space dimensions between patients with unilateral disc displacement without reduction (DDwoR) and asymptomatic individuals, using dynamic jaw tracking and MRI imaging. A total of 47 participants were included: 34 patients diagnosed with unilateral DDwoR and 11 asymptomatic volunteers. Dynamic mandibular movements were recorded using the Zebris JMA 3D ultrasonic jaw tracking system. The amount of condylar distraction was measured using the Electronic Position Analysis (EPA) module. Additionally, MRI scans were performed to assess joint space distances. Statistical comparisons were conducted using appropriate parametric and non-parametric tests, with significance set at p < 0.05. The findings provide insight into the differences in condylar distraction between patients with unilateral DDwoR and healthy volunteers. Patients with DDwoR showed significantly reduced condylar distraction potential an on the affected side compared to controls (p < 0.05). MRI analysis revealed a narrower anterior joint space and limited increase in superior joint space in the DDwoR group. No significant differences were found on the non-affected side compared to the control group. Patients with unilateral DDwoR demonstrate limited condylar distraction capacity and altered joint space dynamics compared to asymptomatic individuals. These findings highlight the mechanical constraints associated with disc displacement and emphasize the importance of functional and morphological evaluation in temporomandibular joint disorders.