Comparison of the flexibility and torsional resistance of nickel-titanium rotary instruments

Weber Schmidt Pereira Lopes, Hélio Pereira Lopes, Carlos Nelson Elias, Marcelo Mangelli, Márcia Valéria Boussada Vieira

Introduction: This study compared the flexibility and torsional resistance of two types of instruments manufactured with special NiTi alloys, and one with conventional NiTi. Methods: Twisted File (TF) instruments manufactured with the R-phase of NiTi (SybronEndo, Orange, CA), and ProFile Vortex instruments (Dentsply Tulsa Dental, Tulsa, OK, USA) made of M-Wire NiTi were compared with RaCe (FKG Dentaire, La Chaux-de-Fonds, Switzerland) instruments made of conventional NiTi. Flexibility and torsion assays were carried out using twenty 25/0.06 instruments from each manufacturer. Statistical analysis was performed by ANOVA. Results: The mechanical resistance of the instruments tested was significantly different. TF were the most flexible instruments, followed by RaCe and ProFile Vortex (P < 0.01). In the torsion assay, ProFile Vortex instruments endured the greatest maximum load and maximum torque values prior to fracture, followed by RaCe and TF (P < 0.01). The torsional resistance values of RaCe and TF were not significantly different (P = 0.061). Conclusion: We observed a relationship between flexibility and torsional resistance (maximum torque and maximum angular deflection in torsion). The most flexible instrument (TF) was the least resistant to torsion, while the least flexible (ProFile Vortex) was the most resistant to torsion. RaCe presented intermediate results for both flexibility and torsional resistance.

Keywords: Mechanical torsion. Nickel. Dental instruments. Titanium.

How to cite: Lopes WSP, Lopes HP, Elias CN, Mangelli M, Vieira MVB. Comparison of the flexibility and torsional resistance of nickel-titanium rotary instruments. Dental Press Endod. 2013 Sept-Dec;3(3):16-22.

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