title: The cost, effectiveness and cost effectiveness of removal and retention of asymptomatic, disease free third molars.
abstract: OBJECTIVE
  The study was undertaken to identify the least costly, most effective and most cost-effective management strategy for asymptomatic, disease free mandibular third molars.
  
  
  METHODS
  A decision tree model of the outcomes of mandibular third molar retention and removal was constructed. Probability data for possible outcomes were obtained from a comprehensive literature review and entered into the decision tree. The cost to the NHS in treating each outcome was calculated. 100 patients attending the oral surgery clinics, University of Wales Dental Hospital rated the effect of each outcome on their own life. The cost and effectiveness data for each outcome were entered into the decision tree and the analyses were conducted by 'folding back' the decision tree based on the probabilities.
  
  
  RESULTS
  Mandibular third molar retention was less costly (170 Pounds), more effective (69.5 effectiveness units on a 100 point scale) and more cost-effective (2.43 Pounds per unit of effectiveness) than removal (226 Pounds, 63.3 and 3.57 Pounds respectively). These findings were sensitive to changes in the probability of pericoronitis, periodontal disease and caries.
  
  
  CONCLUSIONS
  Mandibular third molar retention is less costly to the NHS, more effective for the patient and more cost-effective to both parties than removal. However, should the likelihood of developing pericoronitis, periodontal disease and caries increase substantially then removal becomes the more cost-effective strategy.
authors.affiliation: Department of Oral Surgery, Medicine and Pathology, University of Wales College of Medicine Dental School, Heath Park, Cardiff.
authors.forename: M J
authors.initials: MJ
authors.lastname: Edwards
authors.forename: M R
authors.initials: MR
authors.lastname: Brickley
authors.forename: R D
authors.initials: RD
authors.lastname: Goodey
authors.forename: J P
authors.initials: JP
authors.lastname: Shepherd
mesh_terms: D003362:Cost-Benefit Analysis; D003663:Decision Trees; D003731:Dental Caries / Q000191:economics / Q000209:etiology; D017048:Health Care Costs / Q000706:statistics & numerical data; D006801:Humans; D008964:Molar, Third / Q000601:surgery*; D010043:Outcome and Process Assessment, Health Care / Q000379:methods; D010497:Pericoronitis / Q000191:economics / Q000209:etiology; D010510:Periodontal Diseases / Q000191:economics / Q000209:etiology; D019239:Practice Patterns, Dentists' / Q000191:economics / Q000706:statistics & numerical data; D013218:State Dentistry / Q000191:economics*; D014081:Tooth Extraction / Q000191:economics* / Q000706:statistics & numerical data*; D014095:Tooth, Impacted / Q000150:complications / Q000191:economics; D006113:United Kingdom