Influence of cyclic torsional preloading on cyclic fatigue resistance of nickel - titanium instruments
| Autor: | Gianluca Plotino, G. La Rosa, Nicola M. Grande, F. Lo Savio, Eugenio Pedullà, Simona Boninelli, Ernesto Rapisarda |
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| Rok vydání: | 2014 |
| Předmět: |
Cyclic stress
Materials science Surface Properties NiTi fracture Torsion Mechanical CM-wire M-wire cyclic fatigue resistance torsional preload Cyclic fatigue resistance Fatigue resistance Nickel Materials Testing General Dentistry Titanium business.industry Equipment Design Structural engineering musculoskeletal system Preload Torque Nickel titanium Microscopy Electron Scanning Equipment Failure Stress Mechanical business Root Canal Preparation |
| Zdroj: | International endodontic journal (Online) (2014). doi:10.1111/iej.12400 info:cnr-pdr/source/autori:E. Pedullà [1], F. Lo Savio [2], S. Boninelli [3], G. Plotino [4], N. M. Grande [4], E. Rapisarda [1], and G. La Rosa [2]/titolo:Influence of cyclic torsional preloading on cyclic fatigue resistance of nickel-titanium instruments./doi:10.1111%2Fiej.12400/rivista:International endodontic journal (Online)/anno:2014/pagina_da:/pagina_a:/intervallo_pagine:/volume |
| ISSN: | 0143-2885 |
| Popis: | Pedulla E, Lo Savio F, Boninelli S, Plotino G,Grande NM, Rapisarda E, La Rosa G. Influence ofcyclic torsional preloading on cyclic fatigue resistanceof nickel – titanium instruments. International EndodonticJournal. Aim To evaluate the effect of different torsional pre-loads on cyclic fatigue resistance of endodontic rotaryinstruments constructed from conventional nickel-titanium (NiTi), M-Wire or CM-Wire.Methodology Eighty new size 25, 0.06 taperMtwo instruments (Sweden & Martina), size 25, 0.06taper HyFlex CM (Coltene/Whaledent, Inc) and X2ProTaper Next (Dentsply Maillefer) were used. TheTorque and distortion angles at failure of new instru-ments (n = 10) were measured, and 0% (n = 10),25%, 50% and 75% (n = 20) of the mean ultimatetorsional strength as preloading condition wereapplied according to ISO 3630-1 for each brand. Thetwenty files tested for every extent of preload weresubjected to 20 or 40 torsional cycles (n = 10). Aftertorsional preloading, the number of cycles to failurewas evaluated in a simulated canal with 60° angle ofcurvature and 5 mm of radius of curvature. Datawere analysed using two-way analysis of variance.The fracture surface of each fragment was examinedwith a scanning electron microscope (SEM). Datawere analysed by two-way analyses of variance.Results Preload repetitions did not influence thecyclic fatigue of the three brands; however, the 25%,50% and 75% torsional preloading significantlyreduced the fatigue resistance of all instruments tested(P 0.05).Conclusions Torsional preloads reduced the cyclicfatigue resistance of conventional and treated (M-wireand CM-wire) NiTi rotary instruments except for size25, 0.06 taper HyFlex CM instruments with a 25% oftorsional preloading.Keywords: CM-wire, cyclic fatigue resistance,M-wire, NiTi fracture, torsional preload. |
| Databáze: | OpenAIRE |
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