Third-molar extraction as a risk factor for temporomandibular disorder.

BACKGROUND Although third-molar extraction is common in the U.S., there are few reports on the relationship between third-molar extraction and temporomandibular disorder (TMD). The aim of this study was to investigate this potential association. METHODS The authors enrolled study subjects on their 15th birthdays and followed them continuously for a minimum of five years. The authors ascertained exposure (third-molar extraction) and outcome (TMD) via electronic dental insurance records. A survival analysis design estimated the relative risk of experiencing TMD after third-molar extraction. They considered sex, dental care utilization and other potentially confounding variables in the analyses. RESULTS A total of 34,491 subjects met the inclusion criterion. Fifty percent of all subjects had third molars removed by the age of 20 years, and 391 subjects had claims indicating TMD. The adjusted relative risk of experiencing TMD after third-molar extraction was 1.6 (95 percent confidence interval, 1.3 to 2.0). Calculation of the population risk indicated that 23 percent of all TMD cases in this age group might be due to third-molar extraction. CONCLUSIONS Third-molar extraction appears to be a risk factor for TMD. CLINICAL IMPLICATIONS Dental providers should be aware of the risk of experiencing TMD related to third-molar extraction and take measures to minimize trauma to the joint during extraction.