Failure mechanism of ProTaper Ni–Ti rotary instruments during clinical use: fractographic analysis

Spanaki-Voreadi, A. P.; Kerezoudis, N. P.; Zinelis, Spiros

doi:10.1111/j.1365-2591.2006.01065.x

Cited by 64 publications

(61 citation statements)

References 22 publications

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“…In the S1 file the SEM photomicrographs showed that fatigue cracks in this file were present after the first use. The fractures found in this present work were due to fatigue, this type of fracture in ProTaper ins-truments has also been described by SpanakiVoreadi et al (19), Peng et al (11) and Wei et al (14) , although the latter also found torsion fractures. Peng et al (11) reported a similar fracture percentage (24.6%) to the one observed here in S1 files.…”

Section: Discussionsupporting

confidence: 87%

Microstructure alterations of rotary files after multiple simulated operative procedures

Luzi

Forner²,

Almenar³

et al. 2010

Med Oral

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Aim: To assess morphological alterations of ProTaper rotary NiTi files before and after continuous use by scanning electron microscopy (SEM). Study Design: 30 root canals were chosen with an angle between 15 and 30º. Before starting to prepare the canals the files were observed microscopically using a scanning electronic microscope. The ProTaper sequence recommended by the manufacturer was used, with NaOCl as irrigant. The instruments were sterilised after every three canals were shaped. The instruments were observed with the same microscope after shaping each canal, until 30 root canals were shaped. The criteria used for checking the instruments were: blunt cutting edges, disruption of cutting edge, microfractures, fatigue cracks, metal flash, dentine remains. Results: Many microscopic defects were found such as: cutting edge breaks (up to 70%); fatigue cracks, between 33 and 100%. No microfractures were found. An S1 and an SX file were fractured. Conclusion: ProTaper instruments are quite reliable if used following usual requirements.

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Section: Discussionsupporting

confidence: 87%

Microstructure alterations of rotary files after multiple simulated operative procedures

Luzi

Forner²,

Almenar³

et al. 2010

Med Oral

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“…Two mechanisms that may lead to NiTi rotary fracture, namely cyclic fatigue and torsional overloading, have been described (2,13,(49)(50)(51). Cyclic fatigue occurs as a result of rotation around a curve by repeated extension and compression of the metal and, finally, work hardening followed by fracture (15,49).…”

Section: Mechanical Performance Of Thermomechanically-treated Niti Inmentioning

confidence: 99%

Current Challenges and Concepts of the Thermomechanical Treatment of Nickel-Titanium Instruments

Shen

Zhou

Zheng

et al. 2013

Journal of Endodontics

459

438

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Introduction: The performance and mechanical properties of nickel-titanium (NiTi) instruments are influenced by factors such as cross-section, flute design, raw material, and manufacturing processes. Many improvements have been proposed by manufacturers during the past decade to provide clinicians with safer and more efficient instruments. Methods: The mechanical performance of NiTi alloys is sensitive to their microstructure and associated thermomechanical treatment history. Heat treatment or thermal processing is one of the most fundamental approaches toward adjusting the transition temperature in NiTi alloy, which affects the fatigue resistance of NiTi endodontic files. The newly developed NiTi instruments made from controlled memory wire, M-Wire (Dentsply Tulsa Dental Specialties, Tulsa, OK), or R-phase wire represent the next generation of NiTi alloys with improved flexibility and fatigue resistance. The advantages of NiTi files for canal cleaning and shaping are decreased canal transportation and ledging, a reduced risk of file fracture, and faster and more efficient instrumentation. The clinician must understand the nature of different NiTi raw materials and their impact on instrument performance because many new instruments are introduced on a regular basis. Results: This review summarizes the metallurgical properties of next-generation NiTi instruments, the impact of thermomechanical treatment on instrument flexibility, and the resistance to cyclic fatigue and torsion. Conclusions: The aim of this review was to provide clinicians with the knowledge necessary for evidence-based practices, maximizing the benefits from the selection and application of NiTi rotary instruments for root canal treatment. (J Endod 2013;39:163-172)

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“…However, single-use instruments are used in one tooth, even if the tooth has three or four root canals, as in the case of molars, and are suitable for curved and atretic canals (12). Studies suggest that a disadvantage of single-use instruments is excessive tensile and compression forces on the instrument, which occur with instruments in continuous rotary systems and can cause fracture (13,14).…”

Section: Introductionmentioning

confidence: 99%

Comparison of cyclic fatigue and torsional resistance in reciprocating single-file systems and continuous rotary instrumentation systems

et al. 2014

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Failure mechanism of ProTaper Ni–Ti rotary instruments during clinical use: fractographic analysis

Abstract: The results suggest that a single overloading event causing ductile fracture of ProTaper instruments is the most common fracture mechanism encountered under the clinical conditions.

Cited by 64 publications

References 22 publications

Microstructure alterations of rotary files after multiple simulated operative procedures

Microstructure alterations of rotary files after multiple simulated operative procedures

Current Challenges and Concepts of the Thermomechanical Treatment of Nickel-Titanium Instruments

Comparison of cyclic fatigue and torsional resistance in reciprocating single-file systems and continuous rotary instrumentation systems

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