Use of Photobiomodulation to Reduce Postoperative Pain, Edema, and Trismus After Third Molar Surgery: A Systematic Review and Meta-Analysis

Third molar extraction can cause surgical trauma, which is associated with pain, edema, trismus, and functional limitations. The aim of the present systematic review was to investigate the effects of photobiomodulation (PBM) following the extraction of impacted mandibular third molars.An electronic search was conducted in 10 databases from inception up to October 2021 and the grey literature, with no restrictions regarding language or year of publication. Randomized controlled clinical trials (RCT) were included. Studies that were not RCTs were excluded. Reviewers independently analyzed titles and abstracts, followed by full-text analysis. This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The exposure variable was the use of PBM and the outcomes were pain, edema, and trismus. Meta-analysis was performed using a random-effects model. The estimate was calculated considering standardized mean differences (SMD) and respective 95% confidence intervals (CI) obtained for each outcome on the first, second, third and seventh postoperative days. The level of evidence was assessed using the GRADE approach.The search resulted in the 3,324 records. Thirty-three RCTs were included in the systematic review and 23 of these were included in the meta-analyses. The studies involved a total of 1,347 participants (56.6% female and 43.4% male) between 16 and 44 years of age. A greater reduction in pain was found in the PBM group compared to the control group on the third postoperative day (SMD: -1.09; 95% CI: -1.63; -0.55; P < .001; low certainty). Edema was discretely lower in the PBM group on the second postoperative day (SMD: -0.61; 95% CI: -1.09; -0.13; P < .001; low certainty) and trismus was discretely lower in the PBM group on the seventh postoperative day (SMD: 0.48; 95% CI: 0.00; 0.96; P < .001; very low certainty).The evidence of the effect of PBM regarding the control of pain, edema, and trismus following third molar extractions is low or very low.