Evaluation of a new nickel-titanium system to create the glide path in root canal preparation of curved canals.

Introduction: Nickel-titanium rotary instruments recently have been introduced with the purpose of creating an initial glide path. The purpose of this study was to compare the maintenance of canal anatomy, the occurrence of apical transportation, and the working time observed using mechanised instrumentation with the new G-File rotary system (Micro-Mega, Besancon Cedex, France) with those observed using instrumentation with the PathFile system (Dentsply Maillefer, Ballaigues, Switzerland) and manual instrumentation with K-type files (Micro-Mega) to create a glide path in curved root canals. Methods: The mesial canals of 45 mandibular molars (with curvature angles between 25 and 35) were selected. The specimens were randomly divided into 3 groups with 15 canals each, and canal preparations were performed by an endodontist using #12-17 G-File rotary instruments (group GF), #13-16-19 PathFile rotary instruments (group PF), and #10-15-20 K-type stainless steel manual files (group M). A digital double radiographic technique was used to determine apical transportation and the change in the angle of curvature. The working time was also calculated. Results: No statistically significant differences in the angle of canal curvature and apical transportation were found between the groups. However, concerning the working time, specimens from the group who underwent canal preparation using #12-17 G-File rotary instruments achieved significantly lower mean values when compared with the other 2 groups, whereas the group who underwent canal preparation using the #10-15-20 K-type stainless steel manual files had the highest values. Conclusions: The G-File rotary instruments, the PathFile system, and the manual instruments did not have any influence on the occurrence of apical transportation nor did they produce a change in the angle of canal curvature. The G-File instruments seemed to be the most rapid system in creating a safe glide path.