Canal configuration of the mesiobuccal root of the maxillary second molar.

The purpose of this study was to investigate the canal configuration in the mesiobuccal root of the maxillary second molar. The canal configuration of the mesiobuccal root of the maxillary second molar need not be the same as that of the maxillary first molar. Several studies have been attempted to clarify the configuration of the second molar, usually via postoperative evaluation, sectioning, or radiography. To follow more closely the clinical procedure, this study involved access cavity preparation and radiographs taken with files in place. Of the 73 extracted maxillary second molars investigated, 67 teeth (91.8%) had 3 roots whereas 6 teeth (8.2%) had 2 roots. In the three rooted teeth, the mesiobuccal roots of 40 (59.7%) were classified as type I (single canal from orifice to apex), 14 (20.9%) were type II (two canals merging short of the apex into a single canal at the apex), 11 (16.4%) were type III (two separate and distinct canals from orifice to apex), and 2 (3%) were type IV (single canal at the orifice, dividing in midroot into two canals exiting at the apex).