Effect of surface defects and cross-sectional configuration on the fatigue fracture of NiTi rotary files under cyclic loading

Shin, Yu Mi; Kim, Euiseong; Kim, Kwang Man; Kum, Kee‐Yeon

doi:10.5395/jkacd.2004.29.3.267

Cited by 6 publications

(4 citation statements)

References 7 publications

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“…This result is consistent with those of the previous studies. 11,12) Therefore, more controlled studies regarding the effect of instrument designs on the fatigue fracture are necessary.…”

Section: ⅳ Discussionmentioning

confidence: 99%

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Effect of cross-sectional area of 6 nickel-titanium rotary instruments on the fatigue fracture under cyclic flexural stress: A fractographic analysis

Hwang

Lee

et al. 2009

J Korean Acad Conserv Dent

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“…This result is consistent with those of the previous studies. 11,12) Therefore, more controlled studies regarding the effect of instrument designs on the fatigue fracture are necessary.…”

Section: ⅳ Discussionmentioning

confidence: 99%

“…[7][8][9][10][11][12] Several studies have been performed to evaluate the cyclic fatigue in a dynamic model incorporating axial oscillating motion. 13,14) This not only provides a better clinical simulation than the static model, but these studies also demonstrated that the axial (pecking) motion significantly lengthens the life span of the rotary files.…”

mentioning

confidence: 99%

Effect of cross-sectional area of 6 nickel-titanium rotary instruments on the fatigue fracture under cyclic flexural stress: A fractographic analysis

Hwang

Lee

et al. 2009

J Korean Acad Conserv Dent

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“…However, there is little knowledge of the potential role of surface defects on the fatigue failure or the true mode of failure involved. Several studies on cyclic fatigue have been carried out using a dynamic model incorporating axial movement 15,16,22) . This provides a better simulation of the clinical environment.…”

Section: ⅰ Introductionmentioning

confidence: 99%

“…The surface quality can also be an important factor in fatigue fracture. Recent studies using scanning electron microscopy have revealed the presence of micro-fissures, machining marks, metal strips, pits, and blunt cutting edges on the surface of both new and used Ni-Ti rotary instruments [16][17][18][19][20] . These surface defects may initiate microcracks and play a role in the fatigue failure of instruments 21) .…”

Section: ⅰ Introductionmentioning

confidence: 99%

The Effect of Surface Defects on the Cyclic Fatigue Fracture of HEROShaper Ni-Ti rotary files in a Dynamic Model: A Fractographic Analysis

Lee

Kim

Kang

et al. 2007

J Korean Acad Conserv Dent

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This in vitro study examined the effect of surface defects on cutting blades on the extent of the cyclic fatigue fracture of HEROShaper Ni-Ti rotary files using fractographic analysis of the fractured surfaces. A total of 45 HEROShaper (MicroMega) Ni-Ti rotary files with a #30/.04 taper were divided into three groups of 15 each. Group 1 contained new HEROShapers without any surface defects. Group 2 contained HEROShapers with manufacturing defects such as metal rollover and machining marks. Group 3 contained HEROShapers that had been clinically used for the canal preparation of 4-6 molars. A fatigue-testing device was designed to allow cyclic tension and compressive stress on the tip of the instrument whilst maintaining similar conditions to those experienced in a clinic. The level of fatigue fracture time was measured using a computer connected the system. Statistical analysis was performed using a Tukey' s test. Scanning electron microscopy (SEM) was used for fractographic analysis of the fractured surfaces. The fatigue fracture time between groups 1 and 2, and between groups 1 and 3 was significantly different (p < 0.05) but there was no significant difference between groups 2 and 3 (p > 0.05). A low magnification SEM views show brittle fracture as the main initial failure mode. At higher magnification, the brittle fracture region showed clusters of fatigue striations and a large number of secondary cracks. These fractures typically led to a central region of catastrophic ductile failure. Qualitatively, the ductile fracture region was characterized by the formation of microvoids and dimpling. The fractured surfaces of the HEROShapers in groups 2 and 3 were always associated with pre-existing surface defects. Typically, the fractured surface in the brittle fracture region showed evidence of cleavage (transgranular) facets across the grains, as well as intergranular facets along the grain boundaries. These results show that surface defects on cutting blades of Ni-Ti rotary files might be the preferred sites for the origin of fatigue fracture under experimental conditions. Furthermore, this work demonstrates the utility of fractography in evaluating the failure of Ni-Ti rotary files. [J Kor Acad Cons Dent 32(2):130-137, 2007]

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Torsional behavior and microstructure characterization of additively manufactured NiTi shape memory alloy tubes

Safaei

Nematollahi

Bayati

et al. 2021

Engineering Structures

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Effect of surface defects and cross-sectional configuration on the fatigue fracture of NiTi rotary files under cyclic loading

Cited by 6 publications

References 7 publications

Effect of cross-sectional area of 6 nickel-titanium rotary instruments on the fatigue fracture under cyclic flexural stress: A fractographic analysis

Effect of cross-sectional area of 6 nickel-titanium rotary instruments on the fatigue fracture under cyclic flexural stress: A fractographic analysis

The Effect of Surface Defects on the Cyclic Fatigue Fracture of HEROShaper Ni-Ti rotary files in a Dynamic Model: A Fractographic Analysis

Torsional behavior and microstructure characterization of additively manufactured NiTi shape memory alloy tubes

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