Playing with probabilities in dentistry

Dependent from the probabilities of success and failure, one takes risks in daily live. These probabilities are in some instances easily estimated, in other circumstances more difficult to determine. The latter holds especially true in case of 'conditional' probabilities. In regard to dentistry, these probabilities are of importance too; if, for instance, one has to choose between endodontic treatment versus extraction, obliteration of the rootcanal and periapical pathologic processes posses a negative influence on success. This article describes how a probability is changed when a condition datum is assimilated, with use of fictive examples.