The influence of heat treatment on the mechanical properties of Ni-Ti file materials

Self Cite

This study aimed to compare the mechanical properties of differently-tapered EndoWave nickel-titanium endodontic rotary instruments (size #30/0.04 taper and #30/0.06 taper; Group 0.04 and 0.06, respectively). Torsional and bending properties were evaluated with the cyclic fatigue test and the cantilever bending test, respectively. Canal transportation was assessed following instrumentation of curved canals in resin blocks. Torque and apical force during instrumentation were determined using an automated instrumentation and torque/force analyzing device. The number of cycles to fracture was Group 0.04>Group 0.06 (p<0.05). The bending load values were Group 0.06>Group 0.04 (p<0.05). Group 0.04 better maintained the original canal shape compared with Group 0.06. The median clockwise torque value was Group 0.06>Group 0.04 (p<0.05), whereas no significant differences were detected in the median counterclockwise torque and apical force values (p>0.05). Under the present experimental condition, 0.04- and 0.06-tapered EndoWave instruments exhibited different mechanical properties.

Section: Cyclic Fatigue Testmentioning

confidence: 99%

“…An original cantilever bending test apparatus described in previous studies 9,22,29) was used. The test was performed for both instrument groups under the same conditions.…”

Section: Cantilever Bending Testmentioning

confidence: 99%

Comparative analysis of mechanical properties of differently tapered nickeltitanium endodontic rotary instruments

Fukumori

Nishijyo

Tokita

et al. 2018

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“…The martensitic phase deforms with a smaller load compared with the austensitic phase. Moreover, the martensitic transformation stress decreases along with the increase in the austenite transformation finishing temperature (Af) 19,21) . In this regard, one study has reported that row CM wires exhibit higher Af (54.3±4.2°C) compared with conventional NiTi wires (23.6±2.3°C) 23) .…”

Section: Discussionmentioning

confidence: 99%

Evaluation of selected mechanical properties of NiTi rotary glide path files manufactured from controlled memory wires

Nishijo

Ebihara

Tokita

et al. 2018

Self Cite

This study aimed to investigate mechanical properties related to flexibility and fracture resistance of controlled memory wiremanufactured nickel-titanium rotary glide path files [HyFlex EDM Glide Path File (EDM) and HyFlex GPF (GPF)]. Scout RaCe (RaCe) served as control. Bending loads, torsional/cyclic fatigue resistance, and screw-in forces were measured. EDM showed a significantly larger torque at fracture, a longer time to cyclic fracture in reciprocation and a larger screw-in force compared with GPF and RaCe. GPF showed significantly lower bending loads and higher angular deflection values than EDM and RaCe, and a significantly longer time to cyclic fracture than RaCe. The time to cyclic fracture was significantly longer in reciprocation compared with continuous rotation in EDM and GPF. It can be concluded that EDM and/or GPF showed higher flexibility and cyclic/torsional fatigue resistance compared with RaCe; and that reciprocation conferred better cyclic fatigue resistance to EDM and GPF.

“…On the other hand, they are prone to unpredictable fractures due to cyclic fatigue, a result of the alternating tension-compression cycles which they are subject to when rotated near the apical third of root canals with a severe curvature [1][2][3][4][5] . Different manufacturing strategies have been employed to enhance the flexibility and fatigue fracture resistance of NiTi rotary endodontic instruments.…”

Section: Introductionmentioning

confidence: 99%

Cyclic fatigue resistance of OneShape and WaveOne instruments using different angles of curvature

Elsaka

Elnaghy

2015

This study compared the cyclic fatigue resistance of OneShape (OS) instrument which used continuous rotation with WaveOne (WO) instrument which used reciprocating motion. OS size 25, 0.06 taper and WO primary size 25, 0.08 taper were used in simulated canals with 45°, 60°, and 90° angles of curvature until fracture. The number of cycles to fracture (NCF) was recorded to evaluate cyclic fatigue resistance. Data were statistically analyzed using two-way analysis of variance and Tukey's HSD test. Weibull analysis was performed on NCF data. WO had a significantly higher NCF than OS for all angles of curvature (p<0.05). According to Weibull distribution, WO instrument was predicted to have a higher number of cycles to survive than OS instrument. WO instrument which used the reciprocating motion had a greater resistance to cyclic fatigue than OS which used continuous rotation movement.