Objective To evaluate the effect of prophylactic removal of asymptomatic impacted wisdom teeth in adolescents and adults compared with the retention of these wisdom teeth. Methods We searched the Cochrane Oral Health Group Trials Register （to 4 August, 2004）, the Cochrane Central Register of Controlled Trials （CENTRAL）, PubMed （1966 to 4 August, 2004）, EMBASE （1974 to 4 August, 2004）. There was no restriction to publication of language. Key journals were handsearched. An attempt was made to identify ongoing and unpublished trials. All randomised or controlled clinical trials （KCTs/CCTs） comparing the effect of prophylactic removal of asymptomatic impacted wisdom teeth with no-treatment （retention） were included. Assessment of relevance ,validity and data extraction were conducted in duplicate by three independent reviewers. Where uncertainty existed, authors were contacted for additional information about randomisation and withdrawals. The quality assessments of the trials were carried out. Results Only three trials were identified to fulfill the selection criteria. Two complete RCTs assessed the influence of prophylactic removal on late incisor crowding in adolescents. One ongoing RCT was identified, but the researchers were unable to provide any data and intended to publish in the near future. Although both complete trials met the inclusion criteria, different outcome measures were prevented us from pooling data. Conclusions No evidence has been found to support or refute routine prophylactic removal of asymptomatic impacted wisdom teeth in adults. There is some reliableevidence that suggests that the prophylactic removal of asymptomatic impacted wisdom teeth in adolescents neither reduces nor prevents late incisor crowding.