By conducting an oral examination, during radiographic examination and in treatment planning procedures dentists make numerous decisions. A dentist will be required to make his decisions explicit. Decision trees and decision analyses may play an important role. In a decision analysis, the probability of correct and incorrect decisions are multiplied by the utility of the decision outcomes. The treatment outcome with the highest expected utility should be selected. Complex decision tasks such as the estimation of an individual's caries risk or the diagnosis of bone disorders are currently available as computer applications. Also, a preliminary version of a computer programme which detects caries lesions from bitewing radiographs independent from the dentist has become available. It is expected that the applicability of decision analyses will increase when implemented in the dental practice software packages.