Does Anterior Disc Displacement with Reduction Affect Postoperative Pain Perception After Root Canal Therapy? A Prospective Comparative Clinical Study

Background/Objectives: Temporomandibular disorders may influence the perception of odontogenic pain through shared trigeminal pathways and referred pain mechanisms. This study compared postoperative pain following root canal treatment (RCT) between patients with anterior disc displacement with reduction (ADDwR) and individuals without temporomandibular disorders. Methods: The study was registered at ClinicalTrials.gov (NCT07329413; 8 January 2026). Individuals with irreversible pulpitis and symptomatic apical periodontitis in a vital mandibular molar, with or without ADDwR according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD), were included. After exclusions and losses to follow-up, 70 patients (35 per group) were analyzed. All RCTs were performed by one clinician using a standardized protocol. Postoperative pain was assessed using the Numeric Rating Scale at 6 and 12 h and on postoperative days 1, 2, 3, 5, and 7. Joint pain and maximum mouth opening were recorded preoperatively and on postoperative day 7, and their associations with postoperative pain were analyzed. Results: Patients with ADDwR reported significantly higher pain scores at 6 and 12 h compared with the comparison group (p < 0.05). Multivariable analyses showed that ADDwR, female gender, and age were independently associated with postoperative pain at specific time points (p < 0.05). Additionally, procedure duration was significantly longer in the ADDwR group than in the comparison group (p < 0.05). Conclusions: Patients with ADDwR reported higher levels of early postoperative pain following RCT than individuals without temporomandibular disorders. These findings suggest that temporomandibular conditions may influence postoperative pain perception and should be considered when evaluating postoperative pain complaints.