Torsion and Bending Properties of Shape Memory and Superelastic Nickel-Titanium Rotary Instruments

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• 作者：Elizabeth Ninan ; BDS ; David W. Berzins ; PhD ; ^{david.berzins@marquette.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Bending ; controlled memory wire ; M-wire ; nickel-titanium ; rotary files ; shape memory ; torsion
• 刊名：Journal of Endodontics
• 出版年：2013
• 出版时间：January 2013
• 年：2013
• 卷：39
• 期：1
• 页码：101-104
• 全文大小：369 K

文摘

Recently introduced into the market are shape memory nickel-titanium (NiTi) rotary files. The objective of this study was to investigate the torsion and bending properties of shape memory files (CM Wire, HyFlex CM, and Phoenix Flex) and compare them with conventional (ProFile ISO and K3) and M-Wire (GT Series X and ProFile Vortex) NiTi files.

Methods

Sizes 20, 30, and 40 (n = 12/size/taper) of 0.02 taper CM Wire, Phoenix Flex, K3, and ProFile ISO and 0.04 taper HyFlex CM, ProFile ISO, GT Series X, and Vortex were tested in torsion and bending per ISO 3630-1 guidelines by using a torsiometer. All data were statistically analyzed by analysis of variance and the Tukey-Kramer test (P = .05) to determine any significant differences between the files.

Results

Significant interactions were present among factors of size and file. Variability in maximum torque values was noted among the shape memory files brands, sometimes exhibiting the greatest or least torque depending on brand, size, and taper. In general, the shape memory files showed a high angle of rotation before fracture but were not statistically different from some of the other files. However, the shape memory files were more flexible, as evidenced by significantly lower bending moments (P < .008).

Conclusions

Shape memory files show greater flexibility compared with several other NiTi rotary file brands.