Comparison of the Effects of Three Different Nickel–titanium Rotary Instruments on the Fracture Resistance of Obturated Roots: An in vitro Study

Abstract

ABSTRACTAimThe aim of the article is to compare the effects of three different nickel–titanium (NiTi) rotary instruments on the fracture resistance of obturated roots.Materials and methodsA total of 100 permanent mandibular premolars were randomly divided into four groups of 25 teeth each and biomechanical preparation was done: group I: stainless steel K-hand files (HFs), group II: ProTaper NiTi instruments (PT), group III: HyFlex CM NiTi instruments (HCM), and group IV: K3XF NiTi instruments. Following root canal preparation, the canals were obturated using lateral condensation. A light body silicone impression material was used to simulate the periodontal ligament (PDL). Fracture resistance was tested in an Instron testing machine.Statistical analysisData were analyzed with Kruskal–Wallis test.ResultsThere was no difference in significance (p < 0.05) among the different groups tested with respect to their fracture resistances.ConclusionThe present study concluded that rotary instrumentation could result in an increased chance for dentinal defects as compared with hand instrumentation. Greater taper rotary NiTi instruments do not increase the fracture susceptibility of roots, which in turn depends on various factors other than instrumentation alone.Clinical significanceGreater taper achieved by rotary NiTi files during canal preparation facilitates efficient irrigation and complete debridement. Root fracture might occur as a result of microcracks or craze lines that propagate with repeated stress application by occlusal forces and also during canal preparation. Based on the results obtained, it can be decided whether the use of the newer rotary NiTi system contributes to endodontic success and long-term survival of endodontically treated teeth.How to cite this articleShaikh SAH, Shenoy VU, Sumanthini MV, Pawar RB. Comparison of the Effects of Three Different Nickel–titanium Rotary Instruments on the Fracture Resistance of Obturated Roots: Anin vitroStudy. J Contemp Dent 2017;7(2):86-90.