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Laboratory comparison of the mechanical properties of TRUS hape with several nickel‐titanium rotary instruments
Author(s) -
Elnaghy A. M.,
Elsaka S. E.
Publication year - 2017
Publication title -
international endodontic journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.988
H-Index - 119
eISSN - 1365-2591
pISSN - 0143-2885
DOI - 10.1111/iej.12700
Subject(s) - indentation hardness , nickel titanium , cyclic stress , post hoc , materials science , flexibility (engineering) , medicine , dentistry , composite material , mathematics , microstructure , statistics , shape memory alloy
Aim To assess and compare the mechanical properties of TRUS hape ( TRS ) with several nickel‐titanium rotary instruments. Methodology Cyclic fatigue, torsional resistance, flexibility and surface microhardness of TRS (size 25, 0.06v taper), ProTaper Next X2 ( PTN X2, size 25, 0.06 taper), ProTaper Gold ( PTG F2; size 25, 0.08 taper) and ProTaper Universal ( PTU F2; size 25, 0.08 taper) instruments were evaluated. The topographical structures of the fracture surfaces of instruments were assessed using a scanning electron microscope. The cyclic fatigue resistance, torsional resistance and microhardness data were analysed using one‐way analysis of variance ( anova ) and Tukey's post hoc tests. The fragment length and bending resistance data were analysed statistically with the Kruskal–Wallis H ‐test and Mann–Whitney U ‐tests. The statistical significance level was set at P < 0.05. Results PTN and PTG instruments revealed significantly higher resistance to cyclic fatigue than TRS and PTU instruments ( P < 0.001). PTN instruments revealed significantly higher torsional resistance compared with the other instruments ( P < 0.001). PTG instrument had significantly higher flexibility than the other tested brands ( P < 0.05). However, for microhardness, the PTU had significantly higher surface microhardness values compared with other tested brands ( P < 0.05). Conclusions TRS instruments had lower resistance to cyclic fatigue and lower flexibility compared with PTG and PTN instruments. TRS , PTG and PTU instruments had lower resistance to torsional stress than PTN instruments. TRS and PTG instruments had comparable surface microhardness.