Comparison of root canal preparations and apical transportation between nickel-titanium rotary files and stainless steel hand instruments

Purpose: This study aimed to compare the influence of root canal preflaring using stainless steel K-files and rotary nickel-titanium (NiTi) PathFiles on the preservation of the original anatomy of the canals. The incidence of canal transportation and apical transportation were evaluated. Methods: A total of 60 root canals obtained from a pool of freshly extracted human mandibular and maxillary molars were divided into two groups. Each sample was placed on a mould, and pre-and post-instrumentation radiographs were taken. The radiographs were scanned and the angles of the root canal curvatures calculated using computer software (SIDEXIS 5.5/5.5×). Superimpositions were performed to calculate the apical root canal transportation. Results: The results were statistically analysed to compare the two techniques. Significant differences (P < 0.05) regarding the two parameters evaluated were found between the two different instruments. The PathFile group showed significantly less canal transportation (P = 0.011) and less apical transportation (P < 0.001). Conclusions: The results suggest that preflaring with PathFile NiTi rotary files maintained root canal anatomy better than stainless steel hand K-Files in severely curved canals, with curvatures greater than 30 degrees.