Introduction: The aim of this prospective, randomized, double-blind, clinical trial was to evaluate the effect of preoperative, single, oral dose of a long-acting non-steroidal antiinlammatory drug (NSAID; 20mg piroxicam) compared to placebo on post-endodontic pain after single-visit endodontic treatment of mandibular molars with non-vital pulp.

Methodology: Seventy patients were randomly equally divided into two groups (n=35): piroxicam and placebo. The medications were given 1hour before treatment. Canal preparation was done using the ProTaper Next system and obturation using the modified single-cone technique. Pain was assessed using the 11-point numerical rating scale (NRS) 6h, 12h, 24h, 48h, 72h and 1w postoperatively. The number of rescue analgesic tablets was recorded. Data were statistically analyzed; significance was set at p > 0.05.

Results: Piroxicam showed less postoperative pain level at 6, 12 and 24 hours (p>0.05). The mean and Standard deviation value for postoperative pain intensity piroxicam and placebo were 0.6 (1.97) and 266 (3.26) at 6 h, 0.63 (2.17) and 2.29(2.91) at 12 h and 0.54 (1.90) and 1.74 (2.44) at 24 h respectively. Patients receiving piroxicam required fewer analgesic tablets than those receiving placebo (p>0.05).
Conclusions: A preoperative single oral dose of piroxicam can be effective in reducing endodontic postoperative pain within the first 24 hours after treatment and the number of rescue analgesic tablets taken by the patient in patients with mandibular molars having a non-vital pulp treated in a single visit.