Clinical and functional outcomes in disc displacement with reduction and without reduction: A comparative study

BACKGROUND: Disc displacement with reduction (DDwR) and disc displacement without reduction (DDwoR) are recognized as distinct diagnostic entities, but comparative data on their functional and physical parameters remain limited. OBJECTIVE: To compare functional and physical parameters between DDwR and chronic DDwoR patients. METHODS: This cross-sectional study included 204 patients with TMJ internal derangement per DC/TMD criteria (91 DDwR, 113 DDwoR). Pain, chewing efficiency, joint sounds, mandibular range of motion, muscle palpation, and occlusal parameters were assessed. RESULTS: DDwoR patients showed greater masticatory pain (p = .013), lower chewing efficiency (p = .004), higher masseter tenderness (p < .001), and more restricted mouth opening and movement (p < .001) than DDwR patients. No differences emerged in pain intensity, activity interference, joint sounds, temporal tenderness, tinnitus, deviation, or midline discrepancy (p > .05). . CONCLUSIONS: DDwoR carries a greater functional and mechanical burden than DDwR. Beyond pain alone, mandibular mobility, masseter tenderness, and occlusal features may improve subtype-specific diagnosis and treatment.