Influence of occlusal reduction on postoperative pain following single-visit root canal treatment in mandibular molars: a randomized controlled trial.

Objectives: Postoperative pain is a frequent complication following root canal treatment, and occlusal reduction (OR) has been suggested as a means to minimize such discomfort. However, existing evidence regarding its effectiveness remains inconclusive. This study aimed to evaluate the influence of OR on postoperative pain following single-visit root canal treatment in mandibular molars. It also examined whether preoperative pain intensity affects the postoperative response to OR. Methods: A total of 280 eligible patients with irreversible pulpitis in their first or second mandibular molars were enrolled and stratified into four groups based on their preoperative pain intensity using the visual analogue scale (VAS): 0, no pain; 1-3, mild; 4-7, moderate; and 8-10, severe. Each group was further allocated into OR or no occlusal reduction (NOR) subgroups using block randomization. Standardized endodontic procedures were performed under rubber dam isolation. Postoperative pain was recorded at 24 hours, 48 hours, and 1 week using the same VAS scale. Data were analyzed using the chi-square tests (p ≤ 0.05). Results: Overall, a statistically significant difference between OR and NOR was found at the 48-hour interval, favoring OR. Stratified analysis showed significant pain reduction at 24 hours in the moderate pain category and near-significant differences in the severe pain group at both 24 hours and 48 hours. Conclusions: OR reduced early postoperative pain most noticeably in patients presenting with moderate to severe preoperative pain, whereas its effect was minimal in asymptomatic or mildly symptomatic cases.