Locating the appropriate apical position always has been a challenge in
clinical endodontics. The cemento-dentinal junction (CDJ), where the pulp
tissue changes into the apical tissue, is the most ideal physiologic apical limit
of the working length. It also is referred to as the minor diameter or the
apical constricture. However, the CDJ and apical constricture do not always
coincide, particularly in senile teeth as a result of cementum deposition,
which alters the position of the minor diameter. Therefore, setting the apical
constricture as the apical limit of the working length, where it is easy to
clean and shape or obturate the canal, is recommended [1,2].