title: Risk factors for third molar extraction difficulty.
abstract: OBJECTIVE
  The purpose of this study was to measure the difficulty of third molar (M3) extractions and to identify demographic, anatomic, and operative variables associated with extraction difficulty.
  
  
  METHODS
  To address the research purpose, we implemented a prospective cohort study and enrolled a sample composed of patients presenting for M3 removal. Predictor variables were categorized as demographic, anatomic, and operative. The primary outcome variable was difficulty of extraction, measured as extraction time per tooth. The secondary outcome variable was the surgeons postoperative estimate of M3 extraction difficulty, measured on a 100-mm visual analog scale (VAS). Appropriate univariate, bivariate, and multivariate statistics were computed.
  
  
  RESULTS
  The sample was composed of 82 subjects, having 250 M3s (53.2% mandibular) extracted, with a mean age of 26.2 +/- 10.7 years; 57.3% were female, 72.0% were white. The mean operating time per M3 extraction was 6.9 +/- 7.6 minutes. The mean estimate of difficulty was 39.6 +/- 24.7 mm and was significantly correlated (r = 0.68) with extraction time (P < .01). Surgical experience, M3 location (maxillary versus mandibular), procedure type, tooth position, number of teeth extracted, and tooth morphology were statistically associated (P < or = .05) with extraction time in a multivariate model.
  
  
  CONCLUSIONS
  Our model indicates that the difficulty of M3 extractions is governed primarily by anatomic and operative factors with minimal influence from demographic factors.
authors.affiliation: Harvard School of Dental Medicine, Boston, MA, USA.
authors.forename: Srinivas M
authors.initials: SM
authors.lastname: Susarla
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Dodson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001291:Attitude of Health Personnel; D001294:Attitude to Health; D015331:Cohort Studies; D005260:Female; D005544:Forecasting; D006801:Humans; D008297:Male; D008334:Mandible / Q000601:surgery; D008437:Maxilla / Q000601:surgery; D008875:Middle Aged; D008964:Molar, Third / Q000473:pathology / Q000601:surgery*; D015999:Multivariate Analysis; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors; D014081:Tooth Extraction / Q000009:adverse effects; D016896:Treatment Outcome