Use of the Kaplan-Meier estimate to reduce biases in estimating the rate of caries progression.

An important determinant of how often to perform dental radiography is how rapidly dental caries progress. Estimates of the rate of progression of dental caries have been biased by the elimination of filled lesions and non-progressing lesions (i.e. censored data) from the analysis. We illustrate the use of the Kaplan-Meier estimate to incorporate information from these cases and demonstrate the effect of using this information on estimates of the rate of progression of approximal caries.