Elsevier

Journal of Endodontics

Volume 41, Issue 1, January 2015, Pages 67-71
Journal of Endodontics

Basic Research
Behavior of Nickel-Titanium Instruments Manufactured with Different Thermal Treatments

https://doi.org/10.1016/j.joen.2014.06.005Get rights and content

Abstract

Introduction

The purpose of this study was to investigate if nickel-titanium instruments with similar designs manufactured by different thermal treatments would exhibit significantly different in vitro behavior.

Methods

Thirty-six instruments each of ProTaper Universal (PTU F1; Dentsply Maillefer, Ballaigues, Switzerland), ProFile Vortex (PV; Dentsply Tulsa Dental Specialties, Tulsa, OK), Vortex Blue (VB, Dentsply Tulsa Dental Specialties), and TYPHOON Infinite Flex NiTi (TYP; Clinician's Choice Dental Products, New Milford, CT) (all size 25/.06) were evaluated. Bending resistance, torsion at failure, and dynamic torsional tests were performed with the instruments (n = 12). Analysis of variance and Tukey post hoc tests were applied.

Results

Flexibility was significantly higher for TYP compared with the other 3 groups (P < .0001). With respect to the maximum torque at failure, PV group showed the highest resistance to twisting (torsional strength) among the analyzed instruments followed by VB, TYP, and PTU. The TYP group exhibited greater angular deflection at failure compared with the other groups (P < .0001). The mean dynamic torque scores during simulated canal preparation were highest for TYP (3.01 ± 0.71 Ncm) and lowest for PV (1.62 ± 0.79 Ncm). However, no significant differences were observed comparing groups PTU with TYP and VB and VB with PV (P > .05). The highest mean forces were recorded with PTU (7.02 ± 2.36 N) and the lowest with TYP (1.22 ± 0.40 N).

Conclusions

TYP instruments were significantly more flexible than the other instruments tested. The PV group had the highest torsional strength and TYP, despite being the most flexible, showed similar torsional moments to the other instruments, whereas its angular deflection was the highest among the groups.

Section snippets

Materials and Methods

PTU F1-SE NiTi wire, PV–M-Wire, VB-specific thermal processes, and TYP shape memory technology (all size 25/.06) were evaluated. These instruments have similar design features such as the diameter at 3 mm from the tip and a triangular cross-section avoiding major geometry influences on the test results 19, 25, 26, 27.

Flexibility was determined using a testing apparatus (Analogica, Belo Horizonte, MG, Brazil) built according to the pertinent specification ISO 3630-1 (28). Twelve instruments of

Results

Bending moments (MB) obtained in the tests are summarized in Figure 1. The flexibility for TYP was significantly higher than that for the other 3 groups (P < .0001). This parameter was also significantly higher for VB compared with PV and PTU (P < .0001) and PV compared with PTU (P = .034).

The results of the torsion tests are shown in Figure 2 and indicate that the torsional resistance (Fig. 2A) of TYP and PTU, measured in terms of maximum torque, was significantly lower than that of PV (P

Discussion

Significant variations exist in raw materials used in the fabrication of endodontic instruments; therefore, it is important for clinicians to understand their differences to take advantage of the latest technology and facilitate good choices to meet anatomic challenges. In a comparison of instruments produced by twisting with those of a geometrically similar NiTi system produced by a grinding process, it was observed that the different manufacturing methods used for producing these instruments

Acknowledgments

Supported in part by Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG No. CDS–22008/12), Belo Horizonte, MG, Brazil, contributing to an exchange scholarship for Érika Sales Joviano Pereira at University of the Pacific, Arthur A. Dugoni School of Dentistry; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Capes), Brasília, DF, Brazil; and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brasília, DF, Brazil.

Dr Ove A. Peters serves as a consultant

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