THE MAXILLARY 2ND MOLAR - VARIATIONS IN THE NUMBER OF ROOTS AND CANALS

A retrospective study was undertaken of 520 completed endodontic treat ments of maxillary second molar teeth which were selected from a speci alty endodontic practice. Radiographs were reviewed and studied, a cla ssification of antomical root and canal variations was devised, and th e frequency with which each variant occurred was recorded. There were six variants which occurred frequently enough to be considered as sepa rate anatomic categories and their frequency of occurrence is illustra ted. The six variants found in the study and their frequency of occurr ence are as follows: (1) three separate roots and three separate canal s (56.9%); (2) three separate roots and four canals (two in the mesiob uccal root) (22.7%); (3) three roots and canals whose mesiobuccal and distobuccal canals combine to form a common buccal with a separate pal atal (9%); (4) two separate roots with a single canal in each (6.9%); (5) one main root and canal (3.1%); and (6) four separate roots and fo ur separate canals including two palatal (1.4%). Clinical examples of these deviant variations are also presented.