Endodontic instrumentation —quo vadis?*

Abstract

The flaring of root canal preparations in order to improve instrumentation and enhance root filling condensation has been stressed in recent endodontic literature. Some authors, however, have suggested that too much flaring could be hazardous in molar root canals. This study was prompted by the occurrence of stripping-type perforations and post perforations in the buccal roots of upper molars and in the mesial roots of lowers. Ten operators instrumented 22 molars utilizing a variety of techniques. The teeth were horizontally sectioned and remaining wall thicknesses were measured under magnification. Excessively thin walls were found on the furcation surfaces of the buccal roots of upper molars and the mesial roots of lowers at a level 2-4 mm apical to the trifurcation or bifurcation. A potential for root stripping and post perforation, which was not readily apparent in pre-operative radiographs, was confirmed. The ramifications of these findings are discussed.