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Kimura S, Ebihara A, Maki K, Kyaw MS, Kasuga Y, Omori S, Okiji T. Phase transformation behavior and mechanical properties of HyFlex EDM nickel-titanium endodontic rotary instrument: Evaluation at body temperature. J Dent Sci 2024; 19:929-936. [PMID: 38618130 PMCID: PMC11010611 DOI: 10.1016/j.jds.2023.07.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 07/31/2023] [Indexed: 04/16/2024] Open
Abstract
Background/purpose Temperature-dependent phase compositional changes influence the mechanical properties of heat-treated nickel-titanium (NiTi) rotary instruments. This study evaluated the phase composition, bending properties, and cyclic fatigue resistance of HyFlex EDM NiTi rotary instruments against differently heat-treated and non-heat-treated NiTi instruments at body temperature (BT). Materials and methods HyFlex EDM OneFile (EDM) instruments, heat-treated HyFlex CM (CM) and Twisted File (TF) instruments, and non-heat-treated K3 instruments (size #25/.08) were subjected to differential scanning calorimetry, and the martensitic, R-phase, and reverse transformation starting and finishing temperatures were determined. A cantilever bending test and a cyclic fatigue test were conducted at BT (37 °C ± 1.0 °C), and the bending load and number of cycles to failure (NCF) were recorded. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U tests (α = 0.05). Results TF and K3 had reverse transformation finishing temperatures lower than BT, while those for EDM and CM were higher than BT. The bending loads at a 0.5 mm deflection were in the order of EDM < TF < CM < K3 (P < 0.05), and those at a 2.0 mm deflection were EDM < CM and TF < K3 (P < 0.05). EDM had the highest NCF among the four instruments (P < 0.05). Conclusion The EDM instrument had a reverse transformation finishing temperature higher than BT indicating its martensite/R-phase composition at BT. The EDM instrument had superior flexibility and greater resistance to cyclic fatigue than the CM, TF, and K3 instruments at BT.
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Affiliation(s)
- Shunsuke Kimura
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Arata Ebihara
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Keiichiro Maki
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Moe Sandar Kyaw
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Yuka Kasuga
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Satoshi Omori
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Takashi Okiji
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
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Thu M, Ebihara A, Maki K, Miki N, Okiji T. Cyclic Fatigue Resistance of Rotary and Reciprocating Nickel-Titanium Instruments Subjected to Static and Dynamic Tests. J Endod 2020; 46:1752-1757. [PMID: 32818563 DOI: 10.1016/j.joen.2020.08.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/28/2020] [Accepted: 08/10/2020] [Indexed: 11/18/2022]
Abstract
INTRODUCTION This study compared the static and dynamic cyclic fatigue resistance of contemporary nickel-titanium instruments with different kinematic, metallurgic, and design features to establish whether the fatigue-reducing effect of the pecking motion differs among different nickel-titanium instruments. METHODS ProTaper Gold (PTG), Hyflex EDM (EDM), Reciproc Blue (RPB), and WaveOne Gold (WOG) files were divided into 2 groups of 10 for the static and dynamic cyclic fatigue resistance tests. A stainless steel artificial canal with 1.5-mm inner diameter, 60° angulation, and 3-mm radius of curvature was used. In the dynamic cyclic fatigue resistance test, speeds were set at 100 and 200 mm/min for the descending and ascending motion, respectively. The number of cycles to fracture (NCF) was calculated, the fractured lengths were recorded, and fractographic analysis of the fractured surfaces was carried out by scanning electron microscopy. Data were analyzed statistically with the Kruskal-Wallis test with Bonferroni correction (alpha = 0.05). RESULTS The RPB and EDM showed significantly higher NCF in the static and dynamic cyclic fatigue resistance tests (P < .05). The dynamic cyclic fatigue resistance test showed significantly higher NCF than the static cyclic fatigue resistance test in the PTG and EDM (P < .05). There was no significant difference between the RPB and WOG (P > .05). CONCLUSIONS In the experimental condition where the ascending speed was higher than the descending speed, the dynamic cyclic fatigue resistance was significantly higher than the static cyclic fatigue resistance in continuous rotary instruments, but not in reciprocating instruments.
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Affiliation(s)
- Myint Thu
- Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TDMU), Tokyo, Japan
| | - Arata Ebihara
- Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TDMU), Tokyo, Japan.
| | - Keiichiro Maki
- Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TDMU), Tokyo, Japan
| | - Nishijo Miki
- Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TDMU), Tokyo, Japan
| | - Takashi Okiji
- Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TDMU), Tokyo, Japan
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Gambarini G, Miccoli G, Seracchiani M, Khrenova T, Donfrancesco O, D'Angelo M, Galli M, Di Nardo D, Testarelli L. Role of the Flat-Designed Surface in Improving the Cyclic Fatigue Resistance of Endodontic NiTi Rotary Instruments. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E2523. [PMID: 31398814 PMCID: PMC6720207 DOI: 10.3390/ma12162523] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 07/30/2019] [Accepted: 08/06/2019] [Indexed: 02/03/2023]
Abstract
The aim of this study was to investigate the role of the flat-designed surface in improving the resistance to cyclic fatigue by comparing heat-treated F-One (Fanta Dental, Shanghai, China) nickel-titanium (NiTi) rotary instruments and similar prototypes, differing only by the absence of the flat side. The null hypothesis was that there were no differences between the two tested instruments in terms of cyclic fatigue lifespan. A total of 40 new NiTi instruments (20 F-One and 20 prototypes) were tested in the present study. The instruments were rotated with the same speed (500 rpm) and torque (2 N) using an endodontic motor (Elements Motor, Kerr, Orange, CA, USA) in the same stainless steel, artificial canal (90° angle of curvature and 5 mm radius). A Wilcoxon-Mann-Whitney test was performed to assess the differences in terms of time to fracture and the length of the fractured segment between the flat- and non-flat-sided instruments. Significance was set at p = 0.05. The differences in terms of time to fracture between non-flat and flat were statistically significant (p < 0.001). In addition, the differences in terms of fractured segment length were statistically significant (p = 0.034). The results of this study highlight the importance of flat-sided design in increasing the cyclic fatigue lifespan of NiTi rotary instruments.
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Affiliation(s)
- Gianluca Gambarini
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
| | - Gabriele Miccoli
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
| | - Marco Seracchiani
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
| | - Tatyana Khrenova
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
| | - Orlando Donfrancesco
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
- Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, Sapienza University of Rome, 00185 Rome, Italy
| | - Maurilio D'Angelo
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
| | - Massimo Galli
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
| | - Dario Di Nardo
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy.
| | - Luca Testarelli
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, 00161 Rome, Italy
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Fangli T, Maki K, Kimura S, Nishijo M, Tokita D, Ebihara A, Okiji T. Assessment of mechanical properties of WaveOne Gold Primary reciprocating instruments. Dent Mater J 2019; 38:490-495. [PMID: 31068550 DOI: 10.4012/dmj.2018-203] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study aimed to evaluate cyclic fatigue resistance and bending properties and torque/force generation of WaveOne Gold (WOG) Primary in comparison with WaveOne (WO) Primary and Reciproc (RE) R25. A cyclic fatigue test revealed that the WOG Primary took significantly longer time to fracture compared with the WO Primary (p<0.05). The WOG Primary had the smallest load values at a deflection of 0.5 and 2 mm (p<0.05), as measured with a cantilever bending test. Torque/force measurement demonstrated that maximum upward force and maximum counterclockwise torque values in the WOG Primary were significantly lower than those in the RE R25 (p<0.05). Under the present experimental condition, the WOG Primary showed a higher cyclic fatigue resistance compared with the WO Primary, a higher flexibility compared with the WO Primary and RE R25, and generated a significantly lower maximum torque compared with the RE R25.
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Affiliation(s)
- Tong Fangli
- Endodontic Department, Stomatological Hospital of Southern Medical University.,Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University (TMDU)
| | - Keiichiro Maki
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University (TMDU)
| | - Shunsuke Kimura
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University (TMDU)
| | - Miki Nishijo
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University (TMDU)
| | - Daisuke Tokita
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University (TMDU)
| | - Arata Ebihara
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University (TMDU)
| | - Takashi Okiji
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University (TMDU)
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FUKUMORI Y, NISHIJYO M, TOKITA D, MIYARA K, EBIHARA A, OKIJI T. Comparative analysis of mechanical properties of differently tapered nickeltitanium endodontic rotary instruments. Dent Mater J 2018; 37:667-674. [DOI: 10.4012/dmj.2017-312] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Yohei FUKUMORI
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU)
| | - Miki NISHIJYO
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU)
| | - Daisuke TOKITA
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU)
| | - Kana MIYARA
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU)
| | - Arata EBIHARA
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU)
| | - Takashi OKIJI
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU)
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Dynamic Torsional and Cyclic Fracture Behavior of ProFile Rotary Instruments at Continuous or Reciprocating Rotation as Visualized with High-speed Digital Video Imaging. J Endod 2017; 43:1337-1342. [DOI: 10.1016/j.joen.2017.03.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Revised: 03/16/2017] [Accepted: 03/17/2017] [Indexed: 11/19/2022]
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Elnaghy AM, Elsaka SE. Effect of sodium hypochlorite and saline on cyclic fatigue resistance of WaveOne Gold and Reciproc reciprocating instruments. Int Endod J 2016; 50:991-998. [DOI: 10.1111/iej.12712] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 10/20/2016] [Indexed: 11/27/2022]
Affiliation(s)
- A. M. Elnaghy
- Department of Endodontics; Faculty of Dentistry; Mansoura University; Mansoura Egypt
| | - S. E. Elsaka
- Department of Dental Biomaterials; Faculty of Dentistry; Mansoura University; Mansoura Egypt
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ELSAKA SE, ELNAGHY AM. Cyclic fatigue resistance of OneShape and WaveOne instruments using different angles of curvature. Dent Mater J 2015; 34:358-63. [DOI: 10.4012/dmj.2014-252] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Shaymaa E. ELSAKA
- Department of Dental Biomaterials, Faculty of Dentistry, Mansoura University
- Department of Restorative Dental Sciences, Al-Farabi College of Dentistry and Nursing
| | - Amr M. ELNAGHY
- Department of Conservative Dentistry and Endodontics, Faculty of Dentistry, Mansoura University
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