What is the risk of future extraction of asymptomatic third molars? A systematic review.

Purpose: The purpose of our report was to determine clinically whether young adults who elect to retain their asymptomatic third molars (M3s) have a risk of undergoing 1 or more M3 extractions in the future.

Materials And Methods: To address our clinical question, we designed and implemented a systematic review. The studies included in the present review were prospective, had a sample size of 50 subjects or more with at least 1 asymptomatic M3, and had at least 12 months of follow-up data available. The primary study variables were the follow-up duration (in years) and the number of M3s extracted by the end of the follow-up period or the number of subjects who required at least one M3 extraction. The annual and cumulative incidence rates of M3 removal were estimated.

Results: Seven studies met the inclusion criteria. The samples sizes ranged from 70 to 821 subjects, and the follow-up period ranged from 1 to 18 years. The mean incidence rate for M3 extraction of previously asymptomatic M3s was 3.0% annually (range 1 to 9%). The cumulative incidence rate for M3 removal ranged from 5% at 1 year to 64% at 18 years. The reasons for extraction were caries, periodontal disease, and other inflammatory conditions.

Conclusions: The cumulative risk of M3 extraction for young adults with asymptomatic M3s is sufficiently high to warrant its consideration when reviewing the risks and benefits of M3 retention as a management strategy.