title: Third-molar extraction as a risk factor for temporomandibular disorder.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Orthodontics, University of Washington, Box 357446, Seattle, WA 98195, USA. ghuang@washington.edu
authors.forename: Greg J
authors.initials: GJ
authors.lastname: Huang
authors.forename: Tessa C
authors.initials: TC
authors.lastname: Rue
mesh_terms: D000293:Adolescent; D000328:Adult; D003729:Dental Care / Q000706:statistics & numerical data; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008964:Molar, Third / Q000601:surgery*; D013705:Temporomandibular Joint Disorders / Q000209:etiology*; D014081:Tooth Extraction / Q000009:adverse effects*