Impacted third molars (I3Ms) are blocked from fully erupting; many I3Ms are asymptomatic, however there could be pain and pathological changes. Historically, I3Ms were removed prophylactically. Current options in the United Kingdom include either retention with standard care (watchful waiting), or removal due to pathological changes. We conducted a systematic review of the prophylactic removal of asymptomatic impacted mandibular third molars (IM3Ms) compared with standard care.

We searched five electronic databases from 1999 onwards. Inclusion criteria: randomized and non-randomized trials, observational studies, and systematic reviews (SRs) comparing the prophylactic removal of IM3Ms with standard care or studies assessing the outcomes of either approach; outcomes included pathology associated with retention, postoperative complications, adverse effects of treatment and health-related quality of life. Two reviewers independently screened all titles and/or abstracts, applied inclusion criteria to potentially relevant publications, and quality assessed and data extracted the included studies. No meta-analysis or network meta-analyses were undertaken.

Following screening of 11,373 references, 13 studies (four cohort studies and nine SRs) were included. One cohort study investigated the prophylactic removal of asymptomatic IM3Ms in comparison with standard care and retention, two investigated the prophylactic removal of asymptomatic IM3Ms, and one studied the retention and standard care of asymptomatic IM3Ms. Two studies reporting surgical complications found no serious complications; however, one study reported intense pain and postoperative infection. Pathological changes due to retention of asymptomatic IM3Ms were reported by three studies. Nine SRs of the management of third molars were included in this review, however none focused solely on IM3Ms.

Consistent with previous systematic reviews, we found no RCT data to support or refute the prophylactic removal of asymptomatic IM3Ms, despite extensive searching of the literature. The review however did identify evidence from two longitudinal studies demonstrating the outcomes when asymptomatic IM3Ms are left in situ.