Is the extraction of third molars a risk factor for the temporomandibular disorders? A systematic review.

BACKGROUND: The aim of this study was to evaluate through a systematic review the extraction of third molars as a risk factor for temporomandibular disorders (TMDs). TYPES OF STUDIES REVIEWED: Randomized and nonrandomized controlled clinical trials where patients underwent third molar extraction and with qualitative evaluation of TMDs before and after extraction were included. RESULTS: After applying the inclusion criteria, seven nonrandomized clinical studies were included. QUIPS tool showed that four articles presented a moderate and three a high risk of bias (RoB). Six studies reported that TMDs presented higher level after removal of third molars ranging from OR, 1.81 to 2.15/RR, 2.1. However, one study showed no significant association. GRADE showed heterogeneity in relation to general results, which means that confidence in the estimated effects varied from low to moderate GRADE. The quality of clinical recommendations decreased especially due to the risk of bias in some of the included studies evaluated with the QUIPS tool. CONCLUSIONS AND PRACTICAL IMPLICATIONS: Third molar extraction can be associated with the development of TMD signs and symptoms. Furthermore, TMD can be aggravated according to the third molar location, the degree of impaction and surgical difficulty, age, and gender. This systematic review highlights the need to perform randomized clinical trials with diagnostic criteria and standardized surgical procedures.