Effect of submucosal dexamethasone injections in the prevention of postoperative pain, trismus, and oedema associated with mandibular third molar surgery: a systematic review and meta-analysis

The aim of this systematic review and meta-analysis was to determine whether there are clinically effective reductions in postoperative pain, oedema, and trismus following submucosal dexamethasone administration during impacted mandibular third molar surgery. An electronic database search was conducted up to and including June 2018. Randomized and quasi-randomized trials assessing the effects of submucosal dexamethasone in adult patients undergoing mandibular third molar surgery were included. The mean differences or standardized mean differences were extracted and pooled using the fixed-effects or random-effects model. Seventeen trials were included and independently assessed for risk of bias. There was low quality evidence that submucosal dexamethasone reduces early postoperative pain, early and late postoperative trismus, and late postoperative oedema after mandibular third molar extraction. Moderate quality evidence was found for the reduction of late postoperative pain and early postoperative oedema. The greatest clinical effect of submucosal dexamethasone injection during impacted mandibular third molar surgery was a reduction of early postoperative pain (number needed to treat (NNT) = 4) and early postoperative oedema (NNT = 5). The reduction in trismus was not clinically significant (<5 mm). Further research focusing on strengthening the quality of evidence, investigating potential harms and a definitive protocol for submucosal administration during mandibular third molar surgery is required.