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Chai G, Guo Z, Wang Y, Li Y, Wang J, Zhang L, Sun Y, Yang C, Xia D, Shi T. Effect of flushing temperature on preparation ability of rotary nickel-titanium files. J Appl Biomater Funct Mater 2021; 19:22808000211014724. [PMID: 34210203 DOI: 10.1177/22808000211014724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
PURPOSE The effect of flushing at different temperatures on the preparation ability of rotary nickel-titanium files was investigated to provide guideline for clinical application. METHODS Sixty ProTaper Universal F1 rotary nickel-titanium files were randomly divided into three groups treated by flushing at 6°C, 23°C, and 40°C. Root canal preparation was conducted by step-by-step method on standardized nickel-titanium instrument fracture models. During preparation, the thrust force was set as 10 N, and water was continuously flushed. The motor speed was 350 rpm (rounds per minute), and the torque was 3.0 N cm. When the set torque was reached, the motor automatically rotated in the reverse direction and was pulled out. RESULTS Root canal preparation was performed using ProTaper Universal F1 rotary nickel-titanium files treated by flushing. The numbers of rotations before the device was fracture were 429.33 ± 214.68, 821.92 ± 410.43, and 1304.92 ± 297.81, respectively. When each root canal was completed, the numbers of instrument rotations were 272.15 ± 88.30, 188.85 ± 34.36, and 163.41 ± 16.18, respectively. Rank sum test and analysis of variance were performed by IBM SPSS Statistics v21.0 software, and both of them were p < 0.01, indicating that the number of cycles to failure (NCF) and the number of instrument rotations for each root tube were statistically different at the three temperatures. CONCLUSIONS The self-made resin-simulated curved root canal can replace the real root canal to complete the root canal preparation experiment. The group of nickel-titanium files treated by flushing at 23°C can prepare more root canals and prolong the life of nickel-titanium files than at 6°C. When flushing was done at 40°C, the number of root canals prepared by nickel-titanium files was the highest, and it was not easy to damage the instrument, but lateral perforation occurred easily during root canal preparation.
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Affiliation(s)
- Guangquan Chai
- Department of Stomatology, The Fourth Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Ziyan Guo
- Department of Stomatology, The First Affiliated Hospital of The Second Military Medical University, Shanghai, China
| | - Yingdi Wang
- Department of Stomatology, The Fourth Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Yanfeng Li
- Department of Stomatology, The Fourth Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Jing Wang
- Department of Stomatology, The Fourth Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Lu Zhang
- Department of Stomatology, The Fourth Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Yidan Sun
- Department of Stomatology, The Fourth Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Chunhao Yang
- Department of Stomatology, The Fourth Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Dong Xia
- Department of Stomatology, The Fourth Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Tingting Shi
- Department of Stomatology, The Fourth Medical Center, Chinese PLA General Hospital, Beijing, China
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Nino-Barrera J, Sanchez-Aleman J, Acosta-Humanez M, Gamboa-Martinez L, Cortes-Rodriguez C. Shot peening increases resistance to cyclic fatigue fracture of endodontic files. Sci Rep 2021; 11:12961. [PMID: 34155287 PMCID: PMC8217493 DOI: 10.1038/s41598-021-92382-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 06/09/2021] [Indexed: 11/09/2022] Open
Abstract
The objective of this study was to assess the resistance to fatigue fracture of conventional nickel–titanium files after undergoing shot peening. Forty NITIFLEX endodontic files, number 30, were divided into two groups; one was submitted to shot peening treatment and the other was not. All instruments were tested for fatigue fracture in simulated canals with a TRI-AUTO ZX endodontic motor. One file of each group was subjected to a residual stress analysis by XRD. Finally, the fractured surface was observed and elemental analysis performed by means of SEM and EDX. Roughness analysis was made by focal variation microscope. The shot peening group showed greater resistance to fatigue fracture; there was no difference in the length of the fractured fragments. XRD results showed the presence of residual compression stresses in the file submitted to shot peening, a decrease in the interplanar spacing, and an increase in the full-width-at-half-maximum and the microstrains. SEM and EDX showed a ductile fracture with zones of fatigue and an equiatomic ratio between the nickel and titanium. Surface roughness increased after the file was subjected to the shot peening procedure. In conclusion, shot peening increases the resistance to fatigue fracture due to the presence of residual compression stresses in files manufactured from a conventional nickel–titanium alloy.
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Affiliation(s)
- Javier Nino-Barrera
- Faculty of Dentistry, Endodontics Program, Universidad Nacional de Colombia, Building 210, Office 301, Bogotá, Colombia.
| | - Jose Sanchez-Aleman
- Faculty of Dentistry, Endodontics Program, Universidad Nacional de Colombia, Building 210, Office 301, Bogotá, Colombia
| | | | - Luis Gamboa-Martinez
- School of Dentistry, Endodontics Program, Universidad El Bosque, Bogotá, Colombia
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Baratto-Filho F, de Freitas JV, Gabardo MCL, Tomazinho FSF, Mazzi-Chaves JF, de Sousa-Neto MD. Analysis of reciprocating system real-time torque variation during root canal preparation. BMC Res Notes 2019; 12:47. [PMID: 30665455 PMCID: PMC6341548 DOI: 10.1186/s13104-019-4080-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 01/11/2019] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE This study monitored real-time torque variation of the WaveOne Gold (WOG) and Reciproc Blue (RB) during root canal preparation of mandibular molars. Thirty-six mandibular molars were prepared with WOG Primary 25.07 (WOGP, n = 36) and the RB R25 25.08 (RBR25, n = 36) for the mesial canals, whereas WOG Large 45.05 (WOGL, n = 18) and RB R40 40.06 (RBR40, n = 18) for the distal. Canal preparation was divided into thirds and the torque, maximum torque and time, were recorded. RESULTS The RBR25 instruments exhibited higher maximum torque in the apical third in contrast to the WOGP instruments (p < 0.05). The intragroup analysis found a significant difference in maximum torque between the cervical and apical thirds, and the middle and apical thirds (p < 0.05) for both instruments (RBR25 and WOGP). The WOGP group had the shortest preparation time (p < 0.05). There were no significant differences between the WOGL and RBR40 for any of the parameters evaluated (p > 0.05). The RBR25 had the highest torque when compared to the WOGP. Both instruments exhibited higher torque in the apical third and there were no significant differences between the instruments in the distal canal.
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Affiliation(s)
- Flares Baratto-Filho
- School of Health Sciences, Universidade Positivo, Rua Prof. Pedro Viriato Parigot de Souza 5300, Curitiba, Paraná, 81280-330, Brazil.
| | - Jéssica Vavassori de Freitas
- School of Health Sciences, Universidade Positivo, Rua Prof. Pedro Viriato Parigot de Souza 5300, Curitiba, Paraná, 81280-330, Brazil
| | - Marilisa Carneiro Leão Gabardo
- School of Health Sciences, Universidade Positivo, Rua Prof. Pedro Viriato Parigot de Souza 5300, Curitiba, Paraná, 81280-330, Brazil
| | - Flávia Sens Fagundes Tomazinho
- School of Health Sciences, Universidade Positivo, Rua Prof. Pedro Viriato Parigot de Souza 5300, Curitiba, Paraná, 81280-330, Brazil
| | - Jardel Francisco Mazzi-Chaves
- Department of Restorative Dentistry, Universidade de São Paulo, Avenida do Café s/n, Ribeirão Preto, São Paulo, 14040-904, Brazil
| | - Manoel Damião de Sousa-Neto
- Department of Restorative Dentistry, Universidade de São Paulo, Avenida do Café s/n, Ribeirão Preto, São Paulo, 14040-904, Brazil
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Mechanical and Metallurgical Properties of Various Nickel-Titanium Rotary Instruments. BIOMED RESEARCH INTERNATIONAL 2017; 2017:4528601. [PMID: 29318149 PMCID: PMC5727669 DOI: 10.1155/2017/4528601] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 10/27/2017] [Accepted: 11/02/2017] [Indexed: 11/26/2022]
Abstract
The aim of this study was to investigate the effect of thermomechanical treatment on mechanical and metallurgical properties of nickel-titanium (NiTi) rotary instruments. Eight kinds of NiTi rotary instruments with sizes of ISO #25 were selected: ProFile, K3, and One Shape for the conventional alloy; ProTaper NEXT, Reciproc, and WaveOne for the M-wire alloy; HyFlex CM for the controlled memory- (CM-) wire; and TF for the R-phase alloy. Torsional fracture and cyclic fatigue fracture tests were performed. Products underwent a differential scanning calorimetry (DSC) analysis. The CM-wire and R-phase groups had the lowest elastic modulus, followed by the M-wire group. The maximum torque of the M-wire instrument was comparable to that of a conventional instrument, while those of the CM-wire and R-phase instruments were lower. The angular displacement at failure (ADF) for the CM-wire and R-phase instruments was higher than that of conventional instruments, and ADF of the M-wire instruments was lower. The cyclic fatigue resistance of the thermomechanically treated NiTi instruments was higher. DSC plots revealed that NiTi instruments made with the conventional alloy were primarily composed of austenite at room temperature; stable martensite and R-phase were found in thermomechanically treated instruments.
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Chang SW, Shim KS, Kim YC, Jee KK, Zhu Q, Perinpanayagam H, Kum KY. Cyclic fatigue resistance, torsional resistance, and metallurgical characteristics of V taper 2 and V taper 2H rotary NiTi files. SCANNING 2016; 38:564-570. [PMID: 26792574 DOI: 10.1002/sca.21301] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 12/31/2015] [Accepted: 01/07/2016] [Indexed: 06/05/2023]
Abstract
The aim of this study was to compare the cyclic fatigue resistance, torsional resistance, and metallurgical characteristics of conventional NiTi wire (V taper 2, V2) and CM wire (V taper 2H, V2H)-based files. Cyclic fatigue and torsional resistance of V2 and V2H were investigated by measuring the number of cycles to fracture, maximum torque at fracture, and maximum angle at fracture. The typical patterns of fatigue and torsional fractures were investigated using a scanning electron microscope (SEM). The metallurgical characteristics were investigated by differential scanning calorimetry (DSC) from -100 °C to 100 °C. The austenite finishing temperature (Af) of each instrument was also measured. The microstructures of the instruments were investigated by a transmission electron microscope (TEM) along with selected area diffraction pattern analysis. The results were statistically analyzed by Mann-Whitney U-test (p = 0.05). V2H showed significantly higher cyclic fatigue resistance and torsional resistance than V2. SEM images of the fractured surfaces showed typical patterns of fatigue and torsional fracture. The DSC analysis of V2 showed one small peak in both the heating and cooling curves. The Af of V2 was -0.32 °C. V2H showed two remarkable peaks in the heating curve and one remarkable peak in the cooling curve. The Af of V2H was 33.25 °C. The TEM analysis showed that both V2 and V2H are mainly composed of austenite. In conclusion, V2H showed higher cyclic fatigue resistance and torsional resistance than V2. The superior properties of V2H could be attributed to the annealing effect and possibly the martensite phase. SCANNING 38:564-570, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- S W Chang
- Department of Conservative Dentistry, School of Dentistry, Kyung Hee University, Seoul, Korea
| | - K S Shim
- Department of Conservative Dentistry, School of Dentistry, Kyung Hee University, Seoul, Korea
| | - Y C Kim
- Biomedical Research Institute, Korea Institute of Science and Technology, Seoul, Korea
| | - K K Jee
- Future Convergence Research Division, Korea Institute of Science and Technology, Seoul, Korea
| | - Q Zhu
- Division of Endodontology, Department of Oral Health and Diagnostic Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, Connecticut
| | - H Perinpanayagam
- Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - K Y Kum
- Department of Conservative Dentistry, Dental Research Institute and BK21 Program, Seoul National University Dental Hospital, Seoul National, University School of Dentistry, Seoul, Korea
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