The effect of thermal treatment on the resistance of nickel-titanium rotary files in cyclic fatigue

Zinelis, Spiros; Darabara, M.; Takase, Toshiyuki; Ogane, Kaoru; Papadimitriou, G.

doi:10.1016/j.tripleo.2006.12.026

Cited by 81 publications

(77 citation statements)

References 13 publications

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“…DSC curves were very complex with irregular peaks. These results were also confirmed by other studies (28,32). Therefore, the manufacturer must perform an appropriate heat treatment, which will be accompanied by beneficial changes in mechanical properties and improved clinical performance.…”

Section: Metallurgical Characterization Of Thermomechanically-treatedsupporting

confidence: 82%

“…Four methods (13) have been used to investigate in vitro fatigue fracture resistance of NiTi rotary endodontic instruments: (1) curved metal tube (49), (2) grooved block-and-rod assembly (54-60), (3) rotation against an inclined plane (61, 62), and (4) 3-point bend of a rotating instrument (32,63,64). However, in an effort to understand the nature of the metal alterations and their impact on enhancing resistance to fatigue in particular, an international standard for cyclic fatigue testing of NiTi rotary instruments should be developed in order to ensure the uniformity of methodologies so that the resulting data can be compared (15).…”

Section: Fatigue Propertiesmentioning

confidence: 99%

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

Shen

Zhou

Zheng

et al. 2013

Journal of Endodontics

424

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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Section: Metallurgical Characterization Of Thermomechanically-treatedsupporting

confidence: 82%

Section: Fatigue Propertiesmentioning

confidence: 99%

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

Shen

Zhou

Zheng

et al. 2013

Journal of Endodontics

424

438

View full text Add to dashboard Cite

show abstract

“…Some authors relate instrument fracture to fatigue caused by repetitive bending stresses on curved canals. 11,12 Others indicate torsion as the primary mechanism responsible for fracture. 13 Torsion can be generated when the rotary file is obstructed against the canal wall or exposed to excessive pressure by the clinician.…”

Section: Discussionmentioning

confidence: 99%

Micro-CT assessment of two different endodontic preparation systems

Moura-Netto

Palo

Camargo³

et al. 2013

Braz. oral res.

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The aim of this study was to compare two endodontic preparation systems using micro-CT analysis. Twenty-four one-rooted mandibular premolars were selected and randomly assigned to two groups. The samples (n = 12) of Group 1 were prepared using the ProTaper Universal rotary system, while Group 2 (n = 12) was prepared using the EndoEZE AET system complemented by manual apical preparation with K-type hand files up to #30. A 2.5% sodium hypochlorite solution was used in both groups for irrigating. Both groups were scanned by highresolution microcomputed tomography before and after preparation (SkyScan 1172, SkyScan, Kontich, Belgium). The root canal volume and surface area was measured before and after preparation, and the differences were calculated and analyzed for statistically significant differences using ANOVA complemented by the Tukey test (p < 0.05). The results showed no statistically significant differences between the mean volumes of dentin removal by the two systems. However, the EndoEZE AET system presented a significantly greater mean surface area compared to the ProTaper system (p < 0.05). The EndoEZE AET system enabled preparation of a greater root canal surface area when compared to the ProTaper Universal system. There seemed to be no difference in dentin volume loss between the two systems used.

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“…Twisted method was introduced as one of the manufacturing methods that can increase the fatigue resistance of end product in comparison to the traditional grinding process (10). Other investigators reported that thermal treatments such as annealing of these instruments can enhance their fatigue resistance (11). Apart from reasons mentioned for the fatigue failure of NiTi instruments, others have suggested that the corrosion mechanisms, as a result of chemomechanical preparation and chemical disinfection or sterilisation, might be an initial factor for fatigue failure.…”

Section: Highlightsmentioning

confidence: 99%

Influence of an Innovative Anti-Corrosive Solution on Resistance of Endodontic NiTi Rotary Instruments: A Preliminary Study

Saghiri¹,

Asatourian²,

Godoy³

2017

Eur Endod J

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Objective:To evaluate the effects of deionised water, blood, phosphate-buffered saline (PBS) and a new anti-corrosive solution based on methoxy propyl amine (MOPA) on the cyclic fatigue resistance of endodontic NiTi rotary instruments under in vitro conditions. Methods: Forty ProTaper F1 files were provided and divided to four groups (n=10). Samples were first autoclaved and then stored in deionised water, blood, PBS or MOPA for 24 hours. Cyclic fatigue was tested with a custom-made stainless-steel block including artificial canals (curvature angle=30 degree, radius of curvature=5 mm). After immersion in test solutions, samples were rotated 300 rpm until fracture occurred. The number of cycles to failure (NCF) was calculated using recorded fracture time. Results: Data were analysed by the Kolmogorov-Smirnov, Levene, ANOVA and Scheffe statistical tests. Samples in blood group showed the lowest and samples in MOPA group showed the highest NCF values. Significant difference was observed between groups (p=0.001). NCF value of PBS group was significantly more than the NCF values of samples in blood and deionised water groups (p<0.05). Conclusion:The tested novel anti-corrosive solution significantly increased the fracture resistance of the endodontic NiTi rotary instruments by reducing the cyclic fatigue. In contrast, blood and deionised water caused more corrosion and resulted in earlier file fracture. Keywords: anti-corrosion, cyclic fatigue, NCF, NiTi rotary INTRODUCTIONThe advent of NiTi rotary instruments to the field of endodontic was a revolutionary change. These devices are made of pseudo-elastic alloy of nickel and titanium (Nitinol 55) and have an incredible influence on the mechanical preparations of root canals (1). The instrumentation of narrow and curved root canals can be challenging for many clinicians. Walia et al. showed that Nitinol files are at least two to three times more flexible than stainless steel (SS) files (2). The flexibility can enable the instrument to be used in curved and complex root canals with more facility and lower root canal shape alterations (3).Many investigators have shown that the unexpected separation of NiTi rotary instruments, apart from higher strength and flexibility, remains a clinical challenge. This undesirable event can occur without any significant deformation seen on the surface of instrument (4). Different causes, such as cyclic fatigue, static and dynamic torsional fatigues, have been attributed to the fracture of these devices (5). Cyclic fatigue is described by the alternating tension and compression cycles, which occur inside the structure of an instrument when it is moving through the maximum curvature of root canal (6). The cyclic fatigue is generally a concern in curved canals, and the many ABSTRACT HIGHLIGHTS• Deionized water and blood can negatively influence the structure of NiTi made devices. • Methoxy propyl amine (MOPA) novel solution is an anti-corrosive agent, which can increase the cyclic fatigue resistance and delay separation of NiTi made rotary...

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The effect of thermal treatment on the resistance of nickel-titanium rotary files in cyclic fatigue

Cited by 81 publications

References 13 publications

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

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

Micro-CT assessment of two different endodontic preparation systems

Influence of an Innovative Anti-Corrosive Solution on Resistance of Endodontic NiTi Rotary Instruments: A Preliminary Study

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