This study aimed to measure the association between apparent diffusion coefficient (ADC) and temporomandibular joint (TMJ) pain.

This retrospective study included patients with suspected TMJ disorders who underwent magnetic resonance imaging. Primary predictor variables included the ADC value. Other predictor variables included the presence of joint effusion (JE), disc displacement, and mandibular condyle deformity. The outcome variable was the presence or absence of TMJ pain. Data were analyzed using binomial logistic regression, with statistical significance set at P < 0.05.

The participant comprised 93 patients with a mean age of 47.42 ± 16.17 years; 80.65 % were female. The mean ADC value of mandibular condylar bone marrow was 0.83 ± 0.16 (× 10 ^–3 mm ² / s ± SD) in the group with joint pain and 0.74 ± 0.18 (× 10 ^–3 mm ² / s ± SD) in the group without pain. A statistically significant association was observed between the ADC value and TMJ pain (odds ratio (OR) = 13.0; 95% confidence interval (CI) = 1.52, 110.94; P = 0.02). No significant associations were found between TMJ pain and JE ( P = 0.26), articular disc displacement ( P = 0.23) or deformities ( P = 0.08). The cutoff value for predicting the presence or absence of pain was 1.23 × 10 ^–3 mm ² /s.

This study demonstrated the efficacy of diffusion-weighted imaging (DWI) for TMJ pain assessment.