Comparison between a hand stainless-steel K file and a rotary NiTi 0.04 taper

Straightening of curved canals is one of the most common procedural errors in endodontic instrumentation. It can lead to ledging, perforation, and stripping of the canal. The problem is commonly encountered when root canal preparation is performed in curved molars. The purpose of this study was to compare the results of root canal preparation by undergraduate dental students using traditional stainless-steel 0.02 taper K files to results obtained using rotary nickel-titanium 0.04 taper files. One hundred ninety six extracted teeth comprising maxillary and mandibular first molars were used. Preoperative and postoperative radiographs of each tooth were taken. Graduate endodontic residents evaluated the radiographs according to the evaluation criteria used by the endodontic department. The presence of errors--such as stripping, perforation, ledging, transportation, zipping, and instrument breakage--was recorded by examining the radiographs.