Dynamic Torsional Resistance of Nickel-Titanium Rotary Instruments

Park, Su‐Young; Cheung, Gary; Yum, Jiwan; Hur, Bock; Park, Jeong-Kil; Kim, Hyeon‐Cheol

doi:10.1016/j.joen.2010.02.016

Cited by 123 publications

(167 citation statements)

References 26 publications

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“…The surfaces observed in this study were fractured from fatigue after repeated shrinking and stretching. This may be slightly different from previous reports (11)(12)(13)(14)(15)19) in that the break occurred instantaneously right across the entire fracture surface, creating a fracture from fatigue in the entire shaft. When using rotary gutta-percha removal Ni-Ti files in clinical practice, it is important to remember to use a file that is thinner than the diameter of the root canal to prevent the file from cutting into the root canal wall, and to consider the duration of file usage and number of times used.…”

Section: Methodscontrasting

confidence: 82%

“…Of particular interest was the observation of the dimpling that appeared when pressure was focused on the center of the shaft (19). The only study to date that also uses a retreatment file is that of Lopes et al (13) (9)(10)(11)(12). However, the fracture surfaces observed in the present study were fracture surfaces of files after undergoing torsional resistance tests, and were not the area of tip immobilization after torsional fracture tests.…”

Section: Methodsmentioning

confidence: 62%

“…In this test, there were no differences in data due to variations in crystal structure of the Ni-Ti files, suggesting that it differs from other tests and can be used to compare superelastic and shape memory Ni-Ti files. SEM shows characteristic dimpling with microvoids (11)(12)(13)(14)(15)19). Of particular interest was the observation of the dimpling that appeared when pressure was focused on the center of the shaft (19).…”

Section: Methodsmentioning

confidence: 99%

“…According to these reports, the rotary Ni-Ti file can remove gutta-percha from the root canal more quickly than hand implements. There have been many reports of various torsional resistance tests performed on Ni-Ti files in use (9)(10)(11)(12)(13)(14)(15). In addition, various designs of gutta-percha removal Ni-Ti files have been documented.…”

Section: Introductionmentioning

confidence: 99%

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Torsional Resistance Tests on Gutta-percha Removal Ni-Ti Files

Miura

Tsujimoto

2013

Int J Oral-Med Sci

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We performed torsional resistance tests to examine the Protaper Retreatment D1, D2 and D3 and the NRT-GPR 3N and 4N, which are Ni-Ti files used to remove gutta-percha in root canal retreatment. On cyclic fatigue failure tests, the D1 was the quickest to break, and the 4N took the longest to break. Torsional bending tests showed the fracture angle to be largest for the 4N, which was significantly different from that of all the other files (p < 0.01). There were no significant differences among the D1, D2 and D3. Torsional torque tests showed that the superelastic D1, that has the largest diameter, had the largest fracture torque. Files with larger diameters had higher fracture torques. On bending torque test, the D1 differed significantly from all the other files (p < 0.01). Significant differences were also seen between different versions of the same file type (p < 0.01). All of the fracture surfaces of files used in torsional resistance tests in the present experiment showed SEM findings that appear to be instantaneous breakage.The results of this experiment indicated that torsional resistance test values varied according to differences in file properties and shape. It may be necessary to consider these results when using files in clinical practice.

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Section: Methodscontrasting

confidence: 82%

Section: Methodsmentioning

confidence: 62%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Torsional Resistance Tests on Gutta-percha Removal Ni-Ti Files

Miura

Tsujimoto

2013

Int J Oral-Med Sci

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“…Furthermore, the shaft length of TF (23 mm, as opposed to 25-mm-long instruments for other groups) may have contributed, in part, to lower torsional resistance; the longer the distance between the shaft and clamped position (site of stress application), the more evenly the torsional stress would be distributed. In addition, when evaluating the torsional strength, distortion angle, and toughness of TF against 4 other NiTi files, the TF exhibited the lowest yield strength and ultimate strength (94).…”

Section: Torsional Propertiesmentioning

confidence: 97%

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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Management of Fractured Instruments

Terauchi¹

2022

Endodontic Advances and Evidence‐Based Clinical Guidelines

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Dynamic Torsional Resistance of Nickel-Titanium Rotary Instruments

Cited by 123 publications

References 26 publications

Torsional Resistance Tests on Gutta-percha Removal Ni-Ti Files

Torsional Resistance Tests on Gutta-percha Removal Ni-Ti Files

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

Management of Fractured Instruments

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