The life table method in clinical dental research

ABSTRACT The purpose of the present study is to introduce and discuss the life table method in dental research. This statistical method provides a maximum utilization of information obtained from clinical follow‐up studies which involve a relationship between binary criteria and time, e.g. number of failures and successes after a certain period of observation. Data from a previous investigation of the 3‐year survival of formocresol‐treated primary molars was used to illustrate the application of the method. The cumulatively obtained survival rate utilizes all information from cases followed for less than the entire period of observation. A principal advantage of the life table method is the smaller sample variation, making the computed survival rate statistically more reliable than that obtained from the direct method. A simple method to test differences between two survival rates is described.