Distinguishing acute and chronic TMD in adolescent patients

This retrospective cross-sectional study aimed to elucidate the clinical and imaging characteristics of chronic temporomandibular disorder (TMD) compared to acute TMD in adolescents, and to identify factors associated with symptom chronicity. The study included 158 adolescent patients with TMD (103 females and 55 males; mean age, 15.08 ± 2.23 years), classified into acute TMD (symptom duration < 6 months) and chronic TMD (symptom duration ≥ 6 months) groups. We identified the adolescent patients with TMD and retrospectively reviewed all clinical reports, panoramic radiography (PR) and magnetic resonance imaging (MRI) images of their temporomandibular joints. The overall female-to-male ratio among adolescent TMD patients was 1.87:1, with no significant difference between groups. Treatment duration was significantly longer in the chronic TMD group (13.95 ± 6.79 months) than in the acute group (8.02 ± 6.22 months, p < 0.001). On PR, both anterior (2.41 ± 0.67 vs. 1.83 ± 0.64 mm, p < 0.001) and posterior joint spaces (2.48 ± 0.73 vs. 2.19 ± 0.69 mm, p = 0.012) were significantly smaller in chronic TMD patients. The nasomaxillary (Na-Mx) midline discrepancy was significantly greater in chronic TMD patients (1.41 ± 1.06 vs. 1.06 ± 1.11 mm, p = 0.045), and anterior disc displacement (ADD) on MRI was significantly more prevalent in chronic TMD patients (86.7% vs. 68.0%, p = 0.007) than in acute TMD patients. Chronic TMD patients also showed higher rates of bruxism (22.7% vs. 39.8%, p = 0.026), bad posture (54.2% vs. 34.7%, p = 0.016), sleep problems (26.5% vs. 10.7%, p = 0.014), headache (25.3% vs. 12.0%, p = 0.042), and irregular diet (30.1% vs. 12.0%, p = 0.007). In logistic regression analysis, treatment duration ≥ 1 year showed the strongest association with chronic TMD (OR = 8.643, 95% CI 3.285-22.738, p < 0.001). The next strongest predictor was anterior joint space narrowing (OR = 7.225, 95% CI 2.550-20.470, p < 0.001), followed by ADD on MRI (OR = 5.448, 95% CI 1.681-17.651, p = 0.005), Na-Mx discrepancy (OR = 5.119, 95% CI 1.720-15.233, p = 0.003), and bruxism (OR = 4.702, 95% CI 1.595-13.865, p = 0.005). In adolescent TMD patients, symptom chronicity was associated with longer treatment duration and structural changes, such as facial midline deviation and ADD. These associations highlight the importance of early diagnosis and timely management to prevent progression and minimize long-term impact.