Shaping ability of single versus multi file rotary Ni-Ti systems in curved root canals

Objectives The aim of this study is to compare the shaping ability (straightening of curved root canals, apical transportation, preparation time) of single and multi-file rotary systems during the preparation of curved root canals in extracted human molar teeth. Methods Sixty mandibular molars were divided according to the instrument used into three groups of 20 teeth each: group PTU (ProTaper Uneiversal), group PTN (ProTaper Next) and group OS (One Shape). Using standardized pre- and post-instrumentation radiographs, straightening of canal curvature was determined using image analysis software. A double-digital standardized radiographic technique was used to determine apical transportation. Preparation time was also recorded. Data were analysed using one-way analysis of variance (ANOVA) and post hoc Tukey’s test, and significance was set at P 0.05. Results During root canal preparation, no instruments fractured. The use of PTN resulted in significantly less canal straightening followed by OS then PT. There were no significant differences between the three groups with respect to apical transportation. PTN were significantly faster than PTU and OS. Conclusion Under the conditions of this study, ProTaper Next Protaper Universal and One Shape instruments respected original canal curvature and were safe to use. Protaper Next was the fastest among them.