Study design to reduce biases in estimating the percentage of carious lesions that do not progress within a time period.
Much of the available information on the rate of caries progression comes from studies in which two examinations have been done and the percentage of lesions that do not progress from a carious state between the examinations recorded. Extrapolation from this type of study is subject to two offsetting biases. On the one hand, slow progressing lesions that have been in a state for a long time before the first examination may progress between examinations. When these are counted as lesions that progress within the time period between the two examinations, there will be an underestimation of non-progressing lesions. On the other hand, slow progressing lesions will be over-represented in the sample of lesions detected at the first examination. This will result in an overestimation of non-progressing lesions. We suggest a three examination protocol to minimize these biases.
D003731:Dental Caries / Q000503:physiopathology*; D006801:Humans; D012107:Research Design; D013997:Time Factors