Canal configuration of the mesiobuccal root of the maxillary first molar of a Japanese sub-population

Aim The aim of this study was to determine the percentage of anatomical can al configurations of the mesiobuccal root of the maxillary first molar in J apanese patients. Methodology Three hundred teeth were obtained from general dentists who kne w absolutely that they were extracted from Japanese patients. The distobucc al and palatal roots were amputated for radiographic convenience. Preoperat ive radiographs were taken of the remaining crown and mesiobuccal root (MBR ) from mesiodistal and buccopalatal directions for each tooth. Routine endo dontic access cavities were prepared and size 08 files were placed through the orifice into the MBR until they were seen at the apex. In some cases pr eparation of the canal orifice with a long shank round burr was necessary t o gain access. In seven teeth, no access to the apex was possible and these teeth were eliminated. In the other 293 teeth, the MBR canal(s) was (were) enlarged up to size 15 file. If another canal opening was found at the ape x a 08 file was inserted into the second opening and passed coronally. Post operative radiographs with file(s) in place were taken from the two directi ons, as before. Results Of the 293 teeth, 123 (42.0%) were Type II, 89 (30.4%) showed Type III systems and 10 (3.4%) were Type IV. Suggestions for identification and treatment of the second canal in the MBR are presented. Conclusions The proportion of cases with two canals in the mesiobuccal root of maxillary first molars from Japanese patients was high and similar to t hat described from studies of other ethnic populations.