Clark's rule vis à vis the buccal object rule: its evolution & application in endodontics.

Originally, Clark's rule was used to identify the position of unerupted or supernumerary teeth (a concept known as oral localization) prior to orthodontic tooth movement or surgical removal. However, the versatility of this rule's principles and concepts are also highly applicable to endodontic diagnosis and treatment. While contemporarily known by many different names, such as the "buccal object rule" and the "cone beam-shift technique," the importance of this rule in endodontics was not recognized in the literature until late in the 20th century, despite historical evidence demonstrating its incorporation into root canal procedures almost 100 years ago.