The cost, effectiveness and cost effectiveness of removal and retention of asymptomatic, disease free third molars

Purpose of investigation 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 and patients 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. Main findings Mandibular third molar retention was less costly (pound 170), more effective (69.5 effectiveness units on a 100 point scale) and more cost-effective (pound 2.43 per unit of effectiveness) than removal (pound 226, 63.3 and pound 3.57 respectively). These findings were sensitive to changes in the probability of pericoronitis, periodontal disease and caries. Principal 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.