Defects in ProTaper S1 instruments after clinical use: fractographic examination

Cheung, Gary Shun Pan; Peng, Bin; Bian, Zhuan; Shen, Ya; Darvell, B.W.

doi:10.1111/j.1365-2591.2005.01020.x

Cited by 173 publications

(206 citation statements)

References 32 publications

(37 reference statements)

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“…The study showed the lifetime discrepancies in identically shaped instruments. Theoretically, identically shaped NiTi instruments should have the same lifetime; however, the machinebased manufacturing process is complex and may produce NiTi instruments with different amounts of internal residual stresses, work hardening and defects along the NiTi instrument 18,19,22,23) , which makes the prospect of lifetime by NCF difficult to attain.…”

Section: Discussionmentioning

confidence: 99%

“…In the engineering field, mechanical fatigue of NiTi alloy mainly occurs as the result of repetitive stress much lower than that required for fracture on a single load application and without any obvious warning 17) . The manufacturing of NiTi instruments often results in internal residual stresses, work hardening and surface defects that limit the overall strength of the instrument 18) . In unused NiTi instruments, work hardening 19) and surface defects 20) have been reported.…”

Section: Introductionmentioning

confidence: 99%

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Deflecting load of nickel titanium rotary instruments during cyclic fatigue

et al. 2012

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The dispersion of the lifetime of NiTi instruments, and their deflecting load (DL) changes during cyclic fatigue were investigated. A total of 120 ProFile NiTi rotary instruments were tested using a specially designed cyclic fatigue testing apparatus with three pins. Using these pins, the instrument was bent and rotated at 300 rpm to fracture. DL was recorded using a load cell attached to the central pin. For each sample, the working time was converted to number of cycles to fracture (NCF) and the mean DL (DLm) was calculated. The averages of NCF and DLm of 120 samples were 584.3±180.5 cycles and 6.44±0.91 N, respectively. All samples showed a sequential decrease in DL during rotation. Based on the present study, it is impossible to estimate the lifetime of a NiTi instrument from NCF. Thus, the change in DL could be an alternative criterion to determine the remaining lifetime.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Deflecting load of nickel titanium rotary instruments during cyclic fatigue

et al. 2012

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“…The overload zone features a typical dimple rupture or so-called ductile failure (35,50,52). A hybrid (austenite-to-martensite) microstructure with a certain proportion of martensite is more likely to have favorable fatigue resistance than a fully austenitic microstructure (53).…”

Section: Fatigue Propertiesmentioning

confidence: 99%

“…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

448

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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“…A fratura por flexão é a mais preocupante e de difícil prevenção, pois ocorre sem o instrumento apresentar sinais visíveis de deformação (Parashos et al, 2004;Cheung et al, 2005;Shen et al, 2006;Spanaki-Voreadi et al, 2006;Cheung e Darvell, 2007). Enquanto na fratura por torção, o instrumento apresenta características de deformação plástica Wie et al, 2007).…”

Section: Introductionunclassified

Avaliação da influência do hipoclorito de sódio na qualidade da superfície e resistência à corrosão de limas de NiTi de diferentes procedências

Franco¹

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Aos meus pais, Regina e Manoel, por acreditarem em mim e ensinarem o verdadeiro significado da palavra família. Obrigada por todo apoio, compreensão, luta, sacrifício e dificuldades que passaram para este sonho se realizasse. Serei eternamente grata! A minha adorada e querida Vó, Adelia Rocha (in memorium), pelo amor incondicional, por me ensinar com muita sabedoria que o mais importante na vida é ter coragem e nunca desanimar ou desistir diante das dificuldades e obstáculos.Muito obrigada! Aos meus irmãos, Rodrigo e Graziella, pelo apoio, amizade, conselhos, por acreditarem em mim e me ensinar todos os dias a importância da partilha e amor fraterno. Vocês são essenciais e insubstituíveis na minha vida! As minhas irmãs de coração, Carolina e Bárbara, pela amizade, confiança, carinho e presença constante em minha vida e, pelo incentivo quando o sacrifico era grande. AGRADECIMENTOS ESPECIAISA Profa. Dra. Elaine Manso Oliveira Franco de Carvalho sem dúvidas, grande incentivadora e responsável por essa conquista. Obrigada por acreditar e me ajudar! Ao Prof. Dr. José Luiz Lage-Marques pela confiança e oportunidades.Ao Prof. Dr. João Humberto Antoniazzi pela paciência, sabedoria, humildade, dedicação me ensinando o que realmente significa ser um Professor, um Orientador e principalmente um Amigo. Sinto-me muito honrada e privilegiada por ter sido sua orientada.A Profa. Dra Neusa Alonso-Falleiros ser humano admirável com condutas profissionais e pessoais exemplares. Obrigada pela convivência e ensinamentos neste período, com certeza o carinho é verdadeiro e eterno.Ao Prof. Dr. Giulio Gavini por toda atenção, compreensão e orientação.Ao Prof. Dr. Isaac Jamil Sayed pela paciência e empenho para que tudo saísse da melhor maneira buscando sempre a excelência e se preocupando com os detalhes na obtenção das imagens. Muito obrigada, sua ajuda foi fundamental! Ao Carlos, por toda dedicação, atenção e companheirismo que mesmo longe sempre esteve presente e disposto a ajudar. AGRADECIMENTOSÀ Deus por estar sempre presente na minha vida e colocar pessoas tão especiais que de alguma forma contribuíram para a conclusão deste trabalho.A amiga Eliana Souza por todos ensinamentos, amizade, conselhos e inspiração para sempre seguir adiante Ao Leonardo e Nathalia pela amizade e por todos conselhos. ABSTRACTThe present paper evaluated the influence of 1% and 2.5% sodium hypochlorite in the quality of the surface finishing and resistance to corrosion of two endodontic files: Ten from the twenty instruments were individually fixed by the handle to a copper wire tip (0.12 mm diameter and 20 cm length) and placed in the interior of an electrochemical cell with 500 mL sodium hypochlorite solution (NaCIO) 1% (Fórmula e Ação) at the environment temperature controlled in 23ºC (±2) until covering the active part of the instrument. Recordings were made with a PAR potentiostat model 273A. The test was repeated in the same pattern to the other ten files from the same commercial brand with NaClO 2.5%. Besides EPPC, the files were submitted to the s...

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Defects in ProTaper S1 instruments after clinical use: fractographic examination

Cited by 173 publications

References 32 publications

Deflecting load of nickel titanium rotary instruments during cyclic fatigue

Deflecting load of nickel titanium rotary instruments during cyclic fatigue

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

Avaliação da influência do hipoclorito de sódio na qualidade da superfície e resistência à corrosão de limas de NiTi de diferentes procedências

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