Effect of Low-level Laser Therapy on Postoperative Pain after Root Canal Retreatment: A Preliminary Placebo-controlled, Triple-blind, Randomized Clinical Trial

INTRODUCTION: Low-level laser therapy (LLLT) is a practical, nonpharmacologic technique for reducing pain. This study evaluated the effect of LLLT on postoperative pain after root canal retreatment (RCR).

METHODS: This study enrolled patients (N = 36) who required root canal retreatment (RCR) on mandibular molar teeth, presented with periapical lesions with periapical index scores of 2 or 3, and had a pain visual analog scale (VAS) <50 and a percussion pain VAS <50. The participants were divided into 2 groups: (1) patients scheduled for RCR followed by LLLT (n = 18) and (2) patients scheduled for RCR followed by a mock LLLT (placebo) (n = 18). Postoperative pain was assessed using the VAS. Data were collected and statistically analyzed with the chi-square test, the independent sample t test, and the Mann-Whitney U test (P = .05).

RESULTS: On the first 4 days, postoperative pain significantly reduced in the LLLT group compared with the placebo group (P  .05). The number of patients who needed analgesics was lower in the LLLT group than in the placebo group (P