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Kyaw MS, Ebihara A, Iino Y, Thu M, Maki K, Kimura S, Htun PH, Okiji T. Effect of preset torque setting on torque/force generation, shaping ability and surface changes of nickel titanium rotary instrument in different root canal curvature locations: An ex vivo study. Dent Mater J 2024; 43:329-337. [PMID: 38583993 DOI: 10.4012/dmj.2023-244] [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: 04/09/2024]
Abstract
The aim of this study was to evaluate how preset torque settings influence the torque, vertical force, and root canal-centering ability of ProGlider and ProTaper NEXT nickel-titanium rotary instruments in canals with different curvature locations. Based on micro-computed tomography, mesial roots of human mandibular molars (25°-40° curvature) were allocated to the apical curvature (apical 1-5 mm) or the middle curvature (apical 5-9 mm) groups, and mandibular incisors (curvature <5°) to the straight canal group. Each group was subjected to automated instrumentation and torque/force measurement with the preset torque of 1, 2.5, or 5 N•cm. Canal-centering ratios were determined with micro-computed tomography. Instrument fracture occurred only in the 2.5 and 5 N•cm groups in curved canals. The preset torque setting and curvature location did not influence canal shaping ability.
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Affiliation(s)
- 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)
- Department of Conservative Dentistry, University of Dental Medicine (Mandalay)
| | - 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)
| | - Yoshiko Iino
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU)
| | - Myint Thu
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, 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 Sciences, 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 Sciences, Tokyo Medical and Dental University (TMDU)
| | - Pyae Hein Htun
- 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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Dhakshinamurthi B, Ashok R, Rajendran MR, Kalaiselvam R, Ramesh SR, Kuzhanchinathan M, Balaji L. Cyclic Fatigue Resistance of Different Glide Path Files in Simulated Double Curved Canal in Continuous Rotary Motion: An In Vitro Study. J Contemp Dent Pract 2023; 24:337-341. [PMID: 38149812 DOI: 10.5005/jp-journals-10024-3510] [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: 12/28/2023]
Abstract
AIM This in vitro study aimed to compare and evaluate the resistance to cyclic fatigue of a newly developed glide path file in a simulated double curvature canal in a cyclic fatigue-testing machine. METHODS In this in vitro study, a static cyclic fatigue-testing machine with a simulated double curve was created and the samples were divided into the following three groups: Group I-HyFlex EDM; group II-TruNatomy file; and group III-Aurum G files and each instrument is continued to rotate in the canal and a number of cycles to failure (NCF) was calculated and Fractographic analysis was done using scanning electron microscope (SEM), and the results were statistically analyzed. RESULTS Statistical analysis was done using parametric methods one-way analysis of variance (ANOVA) shows statistical significance between groups and then Tukey's HSD post hoc tests were used for multiple pairwise comparisons. TruNatomy glide path files had the highest cyclic fatigue resistance when compared to HyFlex EDM and Aurum G files. CONCLUSION The selection of file systems in cleaning and shaping protocols is an enigma to endodontics. From the results of this study, it can be concluded that TruNatomy files had higher cyclic fatigue resistance than other glide path files are canals with double curvature, hence it is suitable for usage in root canals with extreme curvature. CLINICAL SIGNIFICANCE The selection of file systems in cleaning and shaping protocols is an enigma to endodontics. This in vitro study explored the selection protocols for the execution of root canal preparation. Heat treatment of nickel-titanium (NiTi) endodontic files had improved the cyclic fatigue resistance significantly enhancing the clinical life of file systems.
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Affiliation(s)
- Balaji Dhakshinamurthi
- Department of Conservative Dentistry and Endodontics, Sri Ramachandra Dental College and Hospital, Chennai, Tamil Nadu, India
| | - Rupa Ashok
- Department of Conservative Dentistry and Endodontics, Sri Ramachandra Dental College and Hospital, Chennai, Tamil Nadu, India, Phone: +91 9940072721, e-mail:
| | - Mathan Rajan Rajendran
- Department of Conservative Dentistry and Endodontics, Sri Ramachandra Dental College and Hospital, Chennai, Tamil Nadu, India
| | - Rajeswari Kalaiselvam
- Department of Conservative Dentistry and Endodontics, Sri Ramachandra Dental College and Hospital, Chennai, Tamil Nadu, India
| | - Seshan Rakkesh Ramesh
- Department of Conservative Dentistry and Endodontics, Sri Ramachandra Dental College and Hospital, Chennai, Tamil Nadu, India
| | - Manigandan Kuzhanchinathan
- Department of Conservative Dentistry and Endodontics, Sri Ramachandra Dental College and Hospital, Chennai, Tamil Nadu, India
| | - Lakshmi Balaji
- Department of Conservative Dentistry and Endodontics, Sri Ramachandra Dental College and Hospital, Chennai, Tamil Nadu, India
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Thu M, Ebihara A, Maki K, Nishijo M, Kimura S, Nakatsukasa T, Kyaw MS, Okiji T. Effect of different axial speed patterns on cyclic fatigue resistance of rotary nickel-titanium instruments. BMC Oral Health 2022; 22:617. [PMID: 36529721 PMCID: PMC9761994 DOI: 10.1186/s12903-022-02639-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 11/30/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND To evaluate the effect of pecking motions with faster upward speed on the dynamic cyclic fatigue resistance of nickel-titanium rotary instruments with different metallurgy. METHODS Forty each of ProTaper Universal F3 (PTU) and ProTaper Gold F3 (PTG) instruments (size #30/.09) were equally divided into four groups. The test was performed using an 18-mm-long stainless steel artificial canal with a 5-mm radius of curvature, a 45° canal curvature and a 2-mm canal diameter. A downward speed of 100 mm/min was employed, while the upward speed was set at 100, 150, 200 or 300 mm/min. Time to failure (Tf), number of cycles to failure (Nf) and number of pecking motions to failure (Np) were recorded. Statistical analysis was performed using Kruskal Wallis and Mann-Whitney U tests for Tf, Nf, and Np (α = 0.05). RESULTS The 100/300 mm/min group showed significantly higher Np values than the 100/100 mm/min group (p < 0.05), whereas there were no significant differences in Tf and Nf among the tested speed groups (p < 0.05) in either PTU or PTG. PTG exhibited significantly higher Tf, Nf, and Np than PTU (p < 0.05). CONCLUSIONS Under the tested conditions, the fastest upward speed group showed significantly higher cyclic fatigue resistance, as demonstrated by larger Np, than the same speed group. PTG had significantly higher cyclic fatigue resistance than PTU in all groups.
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Affiliation(s)
- Myint Thu
- grid.265073.50000 0001 1014 9130Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 5-45, Yushima 1-chome, Bunkyo-ku, Tokyo, 113-8549 Japan
| | - Arata Ebihara
- grid.265073.50000 0001 1014 9130Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 5-45, Yushima 1-chome, Bunkyo-ku, Tokyo, 113-8549 Japan
| | - Keiichiro Maki
- grid.265073.50000 0001 1014 9130Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 5-45, Yushima 1-chome, Bunkyo-ku, Tokyo, 113-8549 Japan
| | - Miki Nishijo
- grid.265073.50000 0001 1014 9130Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 5-45, Yushima 1-chome, Bunkyo-ku, Tokyo, 113-8549 Japan
| | - Shunsuke Kimura
- grid.265073.50000 0001 1014 9130Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 5-45, Yushima 1-chome, Bunkyo-ku, Tokyo, 113-8549 Japan
| | - Taro Nakatsukasa
- grid.265073.50000 0001 1014 9130Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 5-45, Yushima 1-chome, Bunkyo-ku, Tokyo, 113-8549 Japan
| | - Moe Sandar Kyaw
- grid.265073.50000 0001 1014 9130Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 5-45, Yushima 1-chome, Bunkyo-ku, Tokyo, 113-8549 Japan
| | - Takashi Okiji
- grid.265073.50000 0001 1014 9130Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 5-45, Yushima 1-chome, Bunkyo-ku, Tokyo, 113-8549 Japan
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Liu H, Shabehpour K, Wang Z, Sobotkiewicz T, Kwak SW, Haapasalo M, Ruse ND, Coil JM, Tay FR, Shen Y. Characterisation of deformed or separated nickel-titanium retreatment instruments after clinical use - A multicentre experience: Defect profiles of clinically-used retreatment instruments. J Dent 2021; 117:103939. [PMID: 34953972 DOI: 10.1016/j.jdent.2021.103939] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 12/17/2021] [Accepted: 12/20/2021] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES The present study examined the defect characteristics of clinically-used, discarded nickel titanium rotary retreatment instruments and analysed the impact of clinical use on their metallurgical properties. METHODS 92 XP-endo Shaper (XPS; FKG Dentaire) and 20 XP-endo Finisher (XPFR; FKG Dentaire) instruments with structural deformation or separation were collected after retreatment from four endodontic clinics over a 20-month period. The types of defects and their relative locations were recorded. The lateral and fractured surfaces of the separated instruments were examined with scanning electron microscopy. Differential scanning calorimetry was used to investigate the thermal behaviour of new, deformed and fractured instruments. RESULTS 77 (84%) XPS and 4 (20%) XPFR had an area with structural change while 15 (16%) XPS and 16 (80%) XPFR were fractured. All unfractured, deformed XPFR showed unwinding close to the coronal end of the flute. Fractures in XPS and XPFR were often close to the coronal end of the flutes or the expanding segments of the insruments. Most of the XPS fractures were torsional failure (67%) while XPFR failed predominantly by cyclic fatigue (81%). The austenite-finishing temperature of XPFR (40°C) was higher than that of XPS (35°C). Both XPS and XPFR exhibited 2-stage phase transformations. CONCLUSIONS Torsional failure was more prevalent in XPS instruments and fatigue failure was more prevalent in XPFR instruments. Among the investigated instruments, XPFR were more likely to separate without warning whereas XPS frequently exhibited plastic deformation. The latter may be used as a pre-separation forewarning sign during clinical retreatment. CLINICAL SIGNIFICANCE The failure mode of XP-endo Shaper and XP-endo Finisher used clinically for retreatment appeared to be different. Plastic deformation, the forewarning sign of instrument seaparation, occurs when XP-endo instruments are used for retreatment.
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Affiliation(s)
- He Liu
- Department of Stomatology, Affiliated Hospital of Jining Medical University, China; Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Canada
| | - Kiarash Shabehpour
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Canada
| | - Zhejun Wang
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Canada
| | - Tyler Sobotkiewicz
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Canada
| | - Sang Won Kwak
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Canada; Department of Conservative Dentistry, School of Dentistry, Dental and Life Science Institute, Dental Research Institute, Pusan National University, Yangsan, South Korea
| | - Markus Haapasalo
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Canada
| | - N Dorin Ruse
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Canada
| | - Jeffrey M Coil
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Canada
| | - Franklin R Tay
- Department of Endodontics, The Dental College of Georgia, Augusta University, Augusta, GA, USA.
| | - Ya Shen
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Canada.
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Kwak SW, Shen Y, Liu H, Wang Z, Kim HC, Haapasalo M. Heat Treatment and Surface Treatment of Nickel–Titanium Endodontic Instruments. FRONTIERS IN DENTAL MEDICINE 2021. [DOI: 10.3389/fdmed.2021.769977] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Knowledge and thorough understanding of the characteristics of endodontic nickel–titanium (NiTi) files is paramount for dentists performing root canal treatments to patients. Understanding the behavior of the NiTi files guides the clinicians in choosing the correct instruments for different clinical and anatomical situations. This review focuses on the metallurgical properties of endodontic NiTi files, with a special emphasis on recent developments and improvements in metallurgy and the effects of heat treatment and surface treatment. In this study, the impact that such developments have on the properties of endodontic NiTi files is discussed.
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Yon MJY, Tang MHY, Cheung GSP. Defects and Safety of NiTi Root Canal Instruments: A Systematic Review and Meta-Analysis. FRONTIERS IN DENTAL MEDICINE 2021. [DOI: 10.3389/fdmed.2021.747071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Aim: To review the reported defect and fracture rates of various NiTi instrumentation systems and identify factors that may influence the chance of NiTi file separation clinically.Data Sources: PubMed, EMBASE, and SCOPUS with controlled vocabulary and keywords in various combinations to identify articles that reported on the defects and/or fracture of NiTi instrument used clinically (Jan 1980 till Aug 2021), with additional search manually by going through the list of references of the initially screened articles. Those satisfying the inclusion and exclusion criteria were entered into the analysis.Study Eligibility Criteria, Participants, and Interventions: All studies from the said databases reporting on NiTi root canal instruments that were deformed or separated during normal clinical use.Study Appraisal and Synthesis Methods: Studies with data available and suitable for meta-analysis were grouped according to the general design of the NiTi instruments for comparison. Safety quotient value was calculated based on the rate of instrument distortion and fracture.Results: Various instrument designs exhibited different incidences of distortion and fracture, hence a different “safety quotient” (ratio of the amount of deformed instruments to that of fractures in use). Heat-treated files showed the highest safety quotient value. All brands of NiTi file demonstrated a statistically significantly lower incidence of fracture, if treated as disposable instruments after clinical use in a patient.Limitations: Inclusion of articles written in English only, and grouping of file systems into general design types in the analysis.Conclusions and Implications of Key Findings: NiTi endodontic files should be scrutinized for defects before being used in the root canal. Disposing the NiTi instruments after clinical use in a patient (so-called “single use”) is recommended for minimizing fracture clinically. Certain instrument designs tend to show discernible deformation before they should fracture in the next use.
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Bürklein S, Zupanc L, Donnermeyer D, Tegtmeyer K, Schäfer E. Effect of Core Mass and Alloy on Cyclic Fatigue Resistance of Different Nickel-Titanium Endodontic Instruments in Matching Artificial Canals. MATERIALS 2021; 14:ma14195734. [PMID: 34640131 PMCID: PMC8510035 DOI: 10.3390/ma14195734] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 11/16/2022]
Abstract
Instrument failure during root canal preparation is still a concern among endodontists. However, it remains unclear whether the use of more martensitic alloys or the cross-sectional design parameters (i.e., core mass) significantly improve fracture resistance. The aim of the study was to evaluate the impact of core mass and alloy on dynamic cyclic fatigue resistance of nickel-titanium endodontic instruments in matching artificial canals at body temperature. Two groups were tested. (A) taper 0.04: F360 (Komet, Lemgo, Germany), Twisted file (Sybron Endo, Glendora, CA, USA) (=TF), JIZAI (Mani, Tochigi, Japan) (=J_04) (all size #25) and the variable tapered TruNatomy (Dentsply, Ballaigues, Switzerland) (size #26) (=TN). (B) size #25; taper 0.06: (Mtwo (VDW, Munich, Germany), JIZAI (Mani) (=J_06), and variable tapered Hyflex EDM OneFile (Coltene Whaledent, Altstätten, Switzerland) (=HF). Time, number of cycles to fracture (NCF), and number and length of fractured fragments were recorded and statistically analysed using ANOVA Student-Newman-Keuls, Kruskal–Wallis or Chi-square test (significance level = 0.05). (A) TN showed the significantly shortest time until fracture, followed by TF, F360 and J_04 which also differed significantly, while NCF showed the following order: F360 < TN < TF < J_04 (p < 0.05). Only one J_04 but all instruments of the other groups fractured within the test-limit of 10 min. (B) Mtwo was significantly inferior concerning time until fracture and NCF, compared to J_06 and HF (p < 0.05), which did not differ significantly (p > 0.05). While all Mtwo instruments fractured, only four instruments failed in the other groups (p < 0.05). Within the limitations of this study, alloy and cross-sectional design (i.e., core mass) were critical factors regarding instrument failure, but none of these factors could be determined as a main parameter for increased or decreased time, and cycles to fracture. Rather, it seemed to be the interaction of multiple factors (e.g., longitudinal and cross-sectional design, alloy, and rotational speed) that was responsible for differences in the time and cycles to fracture. Nonetheless, all instruments had lifetimes that allow safe clinical use. However, the superiority or inferiority of an instrument with regard to cyclic fatigue based on laboratory results—even when identical trajectories are guaranteed—may be considered questionable, as the characteristics and design parameters of the instruments vary considerably, and the experimental setups lack additional clinical parameters and thus clinical relevance.
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Affiliation(s)
- Sebastian Bürklein
- Albert-Schweitzer-Campus 1, Central Interdisciplinary Ambulance in the School of Dentistry, Westphalian Wilhelms-University, Building W 30, 48149 Münster, Germany;
- Correspondence: ; Tel.: +49-251-834-7051; Fax: +49-251-834-7894
| | | | - David Donnermeyer
- Albert-Schweitzer-Campus 1, Department of Periodontology and Operative Dentistry, Westphalian Wilhelms-University, Building W 30, 48149 Münster, Germany; (D.D.); (K.T.)
| | - Karsten Tegtmeyer
- Albert-Schweitzer-Campus 1, Department of Periodontology and Operative Dentistry, Westphalian Wilhelms-University, Building W 30, 48149 Münster, Germany; (D.D.); (K.T.)
| | - Edgar Schäfer
- Albert-Schweitzer-Campus 1, Central Interdisciplinary Ambulance in the School of Dentistry, Westphalian Wilhelms-University, Building W 30, 48149 Münster, Germany;
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Perez-Villalba D, Macorra JC, Perez-Higueras JJ, Peters OA, Arias A. Body temperature fatigue behaviour of reciprocating and rotary glide path instruments in sodium hypochlorite solutions alone or combined with etidronate. AUST ENDOD J 2021; 47:450-456. [PMID: 33720489 DOI: 10.1111/aej.12504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/18/2021] [Accepted: 02/25/2021] [Indexed: 11/30/2022]
Abstract
The aim of the study was to compare cyclic fatigue (CF) resistance of reciprocating and rotary glide path instruments in the presence of irrigation solutions at body temperature. CF resistance of 100 instruments (50 ProGlider and 50 WaveOne Gold Glider) was tested in sodium hypochlorite solutions alone (NaOCl) or in combination with etidronate (NaOCl/HEBP). The CF platform with a simulated canal (curvature = 60°/radius = 3 mm) was submerged in a temperature-controlled bath with the solutions kept at 37 ± 1°C controlled by a precision mercury glass thermometer. Instruments were actioned following manufacturer guidelines, and time to failure was recorded and compared among groups with Weibull analysis. Reciprocating glide path preparation instruments were more resistant to CF than rotary instruments in both irrigation solutions. The irrigation solution did not affect the mean life of ProGlider, but reciprocating instruments lasted significantly longer used in presence of NaOCl compared to NaOCl/HEBP.
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Affiliation(s)
- Dario Perez-Villalba
- Department of Conservative and Prosthetic Dentistry, School of Dentistry, Complutense University, Madrid, Spain
| | - José C Macorra
- Department of Conservative and Prosthetic Dentistry, School of Dentistry, Complutense University, Madrid, Spain
| | - Juan J Perez-Higueras
- Department of Conservative and Prosthetic Dentistry, School of Dentistry, Complutense University, Madrid, Spain
| | - Ove A Peters
- School of Dentistry, University of Queensland, Herston, Queensland, Australia
| | - Ana Arias
- Department of Conservative and Prosthetic Dentistry, School of Dentistry, Complutense University, Madrid, Spain
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Li C, Liu L, Li Y, Wang X, Liu H, Bao J, Wang J, Fan J. Preventing nickel-titanium rotary instrument from breakage by continuous irrigation with different fluids during root canal preparation. Medicine (Baltimore) 2021; 100:e23865. [PMID: 33545953 PMCID: PMC7837962 DOI: 10.1097/md.0000000000023865] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 11/15/2020] [Indexed: 11/25/2022] Open
Abstract
To study the effect of continuous irrigation of rotating nickel-titanium instrument with several common clinical fluids on the diameter, breaking length and breaking position of nickel-titanium instrument, so as to provide some reference and theoretical basis for clinical operation and instrument improvement.A standardized curved root canal model was established, and ProTaper Universal (PTU) F1 instrument was selected for root canal preparation. The nickel-titanium F1 instrument was flushed with distilled water, 0.9% NaCl, 0.2% chlorhexidine, 1% sodium hypochlorite and 5% sodium hypochlorite, and the diameter, length and position of the instrument before and after breakage were recorded.Only 5% sodium hypochlorite influenced the diameter of 6 mm marker points under different irrigation conditions (P < .05). There was no statistical difference in the length of broken instruments among all the groups, and torsional deformation mainly occurred at the end of broken instruments. The broken positions of instruments in all the groups were located at the bending segment of the root canal. The breaking frequency of the 5% sodium hypochlorite group was the highest in the area 3-5.5 mm away from apical foramen, while the other 4 groups had the highest breaking frequency in the area 0 to 1.5 mm away from apical foramen.External irrigation with different fluids did not influence the breaking length of instruments. The closer to the apical foramen was, the higher the breaking frequency of instruments was. However, only 5% sodium hypochlorite can affect the diameter of rotary nickel-titanium instruments, and may lead to early breakage of the instrument, indicating that the use of disinfectants, except 5% sodium hypochlorite, cannot reduce breakage resistance of nickel-titanium instrument compared with distilled water flushing. Furthermore, 5% hypochlorite could not be recommended for irrigation in clinical practice.
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Arslan H, Doğanay Yıldız E, Taş G, Karataş E, Tepecik E. Effects of continuous irrigation at room temperature or +4ºC on the cyclic fatigue resistance of K3XF instruments. J Dent Res Dent Clin Dent Prospects 2021; 14:153-157. [PMID: 33408819 PMCID: PMC7770397 DOI: 10.34172/joddd.2020.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Accepted: 07/31/2020] [Indexed: 11/09/2022] Open
Abstract
Background. The present study aimed to evaluate the impact of continuous irrigation with saline solution at room temperature or +4°C on the cyclic fatigue resistance of K3XF files.
Methods. Forty-eight new K3XF files (#30, .04 taper) were randomly assigned to three groups: control group (no irrigation), continuous irrigation with saline solution at room temperature, and continuous irrigation with saline solution at +4°C. The instruments were tested in an artificial, stainless steel root canal with a double curvature at body temperature (37±1°C). Time to fracture was converted to the number of cycles to fracture (NCF). The lengths of the fractured fragments were recorded. Kruskal–Wallis H test and one-way ANOVA were used to analyze data.
Results. K3XF files’ cyclic fatigue resistance was significantly higher in the continuous irrigation groups than in the control group. Continuous irrigation with saline solution at +4°C resulted in higher cyclic fatigue resistance than continuous irrigation with saline solution at room temperature. There were no significant differences between the groups in terms of the fractured fragments’ length.
Conclusion. Within this study’s limitations, continuous irrigation with saline solution increased the NCF of NiTi instruments; decreasing the saline solution’s temperature increased this effect.
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Affiliation(s)
- Hakan Arslan
- Department of Endodontics, Faculty of Dentistry, Health Sciences University, İstanbul, Turkey
| | - Ezgi Doğanay Yıldız
- Department of Endodontics, Faculty of Dentistry, Bursa Uludağ University, Bursa, Turkey
| | - Gizem Taş
- Çorlu Oral and Dental Health Hospital, Tekirdağ, Turkey
| | - Ertuğrul Karataş
- Department of Endodontics, Faculty of Dentistry, Ataturk University, Erzurum, Turkey
| | - Ebru Tepecik
- Private Practice, Dental Clinic, İstanbul, Turkey
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Gomes MS, Vieira RM, Böttcher DE, Plotino G, Celeste RK, Rossi-Fedele G. Clinical fracture incidence of rotary and reciprocating NiTi files: A systematic review and meta-regression. AUST ENDOD J 2021; 47:372-385. [PMID: 33410578 DOI: 10.1111/aej.12484] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2020] [Indexed: 12/01/2022]
Abstract
This systematic review was registered in PROSPERO (CRD42017075917) and aimed to investigate whether the available clinical evidence supports the hypothesis that reciprocating motion results in a lower incidence of nickel-titanium files fracture compared to continuous rotation. Clinical studies that reported the incidence of fracture of engine-driven nickel-titanium files were included. The main exposure was the kinematics, and the primary outcome was the incidence of files fracture. The overall incidence of files fracture was 2.27%, with a trend for higher incidence with rotary motion (2.43%) than with reciprocating (1.0%), though without significant differences. Multiple meta-regression models revealed that the use of nickel-titanium files in more than four teeth and less proficient operators were associated with a higher incidence of file fracture. There was no difference in the clinical incidence of fracture of nickel-titanium instruments between reciprocating and rotary motions; however, other factors were identified.
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Affiliation(s)
- Maximiliano Schünke Gomes
- Pontifícia Universidade Católica do Rio Grande do Sul, School of Health and Life Sciences, Graduate Program in Dentistry, Porto Alegre, Brazil
| | - Rosângela Mello Vieira
- Pontifícia Universidade Católica do Rio Grande do Sul, School of Health and Life Sciences, Graduate Program in Dentistry, Porto Alegre, Brazil
| | - Daiana Elisabeth Böttcher
- Pontifícia Universidade Católica do Rio Grande do Sul, School of Health and Life Sciences, Graduate Program in Dentistry, Porto Alegre, Brazil
| | - Gianluca Plotino
- Private Practice, Grande, Plotino & Torsello - Studio di Odontoiatria, Rome, Italy
| | - Roger Keller Celeste
- Department of Preventive and Social Dentistry, School of Dentistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Giampiero Rossi-Fedele
- Adelaide Dental School, The University of Adelaide, Adelaide, South Australia, Australia
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12
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Mecholsky JJ, Barrett AA, Jones CT, Pace KM, Nair UP. Fractographic analysis of separated endodontic file designs. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2020; 31:104. [PMID: 33140130 DOI: 10.1007/s10856-020-06432-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 09/24/2020] [Indexed: 06/11/2023]
Abstract
Endodontic rotary files are cutting instruments used to perform root canal procedures within a tooth interior. Focusing on quantitative fractographic analysis increases necessary, clinical performance understanding of file separation failure. This research employed controlled, dynamic testing to failure of commercial rotary files, analyzing the fractographic, forensic characteristics in relation to Weibull reliability determination, considering: (1) design analysis; (2) stress concentrations; (3) times to failure; (4) number of cycles to failure (NCF). Ex vivo testing included three file designs, each having constant tip size (0.035 mm), taper (0.06 mm/mm), and length (25 mm). Files were individually tested using an electric, torque-controlled handpiece, rotating within a standardized, simulated canal until fracture separation occurred. Fractographic analysis, including critical measurements, was conducted using the scanning electron microscope (SEM) (PhenomProX, PhenomWorld, NL). Weibull statistical analysis established reliability factors per design group. Fractographic analysis identified separation fractures, processing inclusions, flexural-fatigue striations, and stress concentrations at flute pitches. Calculated NCF median values (1277-EE; 899-VB; 713-PI) demonstrated significant statistical differences among groups (p < 0.001). Separated apical fragments yielded statistically significant differences (p ≤ 0.05) for varying file design groups. Weibull moduli among groups were statistically equivalent. Fractographic analysis exposed a presence of multiple failure factors in addition to defect distribution, governing cyclic fatigue failure originating at stress concentration points irrespective of file design. Fractographic analysis indicated that a change in file design, specifically at the working edges, in addition to improved surface finish, has the potential of reducing failures by lowering points of stress concentration and reducing fracture initiating surface cracks.
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Affiliation(s)
- J J Mecholsky
- Department of Materials Science & Engineering, Center for Dental Biomaterials, College of Engineering, University of Florida, Gainesville, FL, 32611-6400, USA.
- Center for Dental Biomaterials, Department of Materials Science & Engineering, College of Engineering, University of Florida, Gainesville, FL, 32611-6400, USA.
| | - A A Barrett
- Center for Dental Biomaterials, Department of Materials Science & Engineering, College of Engineering, University of Florida, Gainesville, FL, 32611-6400, USA
| | - C T Jones
- Department of Endodontics, College of Dentistry, University of Florida, Gainesville, FL, 32611-6400, USA
- Practice Limited to Endodontics, Melbourne, FL, USA
| | - K M Pace
- Department of Materials Science & Engineering, College of Engineering, University of Florida, Gainesville, FL, 32611-6400, USA
- Alight Solutions, Dallas, TX, USA
| | - U P Nair
- Practice Limited to Endodontics, Dallas, TX, USA
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13
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Serafin M, Biasi MD, Franco V, Generali L, Angerame D. Influence of different motions on the cyclic fatigue resistance of Reciproc and Reciproc Blue endodontic instruments. J Conserv Dent 2020; 22:449-453. [PMID: 33082660 PMCID: PMC7537752 DOI: 10.4103/jcd.jcd_430_19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 07/03/2020] [Accepted: 07/03/2020] [Indexed: 12/11/2022] Open
Abstract
Aim The aim of this study was to evaluate the cyclic fatigue resistance of Reciproc (RCP) and RPC Blue (RCPB) instruments used in continuous rotation, "RECIPROC" mode, and "WAVEONE" mode. Materials and Methods Sixty RCP and 60 RCPB R25 files were used. For each file type, three groups (n = 20) were defined depending on the used kinematics: continuous rotation, "RECIPROC" mode, and "WAVEONE" mode. A stainless-steel artificial canal with 60° angle and 5-mm radius of curvature was milled reproducing the size and taper of the used files. The test device was electrically heated to 35°C to simulate the clinical environment. All files were reciprocated or rotated until fracture. The time to failure and the length of the fractured fragments were measured. A fractographic examination was performed by scanning the electron microscopy to confirm the cause of fracture. Collected data underwent a two-way analysis of variance (α = 0.05). Results RCPB files exhibited better cyclic fatigue resistance than RCP. The "RECIPROC" motion yielded greater cyclic fatigue resistance than the "WAVEONE" movement; the least resistance was observed in the continuous rotation groups. No significant differences were found among groups in terms of length of the fractured fragment. The fractographic analysis confirmed that all scanned samples separated due to cyclic fatigue. Conclusions Within the limitation of the present study, the "RECIPROC" mode increased the cyclic fatigue resistance of the tested instruments compared to "WAVEONE" mode and continuous rotation. To prevent RCP and RCPB file separation, motion kinematics other than the native "RECIPROC" movement should be discouraged in the clinical setting.
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Affiliation(s)
| | - Matteo De Biasi
- Clinical Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | | | - Luigi Generali
- Department of Surgery, Medicine, Dentistry and Morphological Sciences with Transplant Surgery, Oncology and Regenerative Medicine Relevance, University of Modena and Reggio Emilia, Modena, Italy
| | - Daniele Angerame
- Clinical Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
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Uygun AD. Cyclic fatigue resistance of VDW.ROTATE and Reciproc Blue nickel-titanium files at root canal temperature. J Dent Res Dent Clin Dent Prospects 2020; 14:177-180. [PMID: 33408823 PMCID: PMC7770403 DOI: 10.34172/joddd.2020.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 07/01/2020] [Indexed: 11/23/2022] Open
Abstract
Background. This study aimed to compare the VDW.ROTATE instruments with the Reciproc Blue instruments in different kinematics in terms of the cyclic fatigue resistance.
Methods. Sixty instruments, 40 VDW.ROTATE and 20 Reciproc Blue instruments, were divided into three groups (n=20): VDW.ROTATE was used in both continuous rotation and reciprocation, and Reciproc Blue was used in reciprocation only. The cyclic fatigue resistance test was carried out in an artificial canal (60°, r=3 mm) at an intracanal temperature of 35±2°C until fracture, and the time to fracture was recorded in seconds. The data were analyzed statistically using Kruskal–Wallis and Tamhane’s T2 tests (P<0.05).
Results. DAll the reciprocating motion groups resulted in a longer mean duration to failure than the continuous rotation motion group (P<0.05).
Conclusion. It was observed that the Reciproc Blue instruments had higher cyclic fatigue resistance than VDW.ROTATE instruments (P<0.05). Recent studies have shown that reciprocal movement increases cyclic fatigue resistance compared to rotational movement. The VDW.ROTATE instrument, which has a similar size, design, and alloy as the Reciproc Blue instrument, can also be used by clinicians in reciprocating motion with endo motors capable of reciprocating in different directions. However, even if the cyclic fatigue resistance increases by using VDW.ROTATE instruments in reciprocation, the cyclic fatigue resistance is lower than Reciproc Blue instruments.
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Affiliation(s)
- Ahmet Demirhan Uygun
- Department of Endodontics, Faculty of Dentistry, Afyonkarahisar Sağlık Bilimleri University, Afyonkarahisar, Turkey
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15
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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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16
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Sobotkiewicz T, Huang X, Haapasalo M, Mobuchon C, Hieawy A, Hu J, Zhou H, Wang Z, Shen Y. Effect of canal curvature location on the cyclic fatigue resistance of reciprocating files. Clin Oral Investig 2020; 25:169-177. [PMID: 32488488 DOI: 10.1007/s00784-020-03348-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/15/2020] [Indexed: 10/24/2022]
Abstract
OBJECTIVES To determine the effect of the location of the canal curvature on the fatigue resistance of WaveOne (WO), WaveOne Gold (WOG), Reciproc (Rec), and Reciproc Blue (RecB) files, and to examine the phase transformation behaviors of the reciprocating file systems. MATERIAL AND METHODS The instruments were subjected to fatigue testing in five artificial canals with a curvature of 60° angle and a 3-mm radius. The location of the curvature was unique for each canal. Each file was inserted 16 mm into the canal and operated until fracture occurred. The time to fracture was recorded and the length of the fragment was measured. Differential scanning calorimetry was used to characterize the thermal behavior of the files. The number of cycles to failure was analyzed using two-way analysis of variance and the post hoc Tukey test. The Kruskal-Wallis test was used to compare the mean fragment lengths between groups. RESULTS The instruments had significantly lower fatigue resistance in canals with curvatures in the middle and coronal canals compared with those with apical curvatures (p < 0.05). At all tested curvature locations, RecB had superior fatigue resistance compared with WO and Rec (p < 0.05). There were no significant differences between WOG and Rec in canals with curvatures in the middle and coronal canals. The DSC thermograms for RecB exhibit a single exothermic peak during cooling but double endothermic peaks during heating indicating that a two-step phase transformation from martensite to R-phase to austenite takes place. CONCLUSIONS The reciprocating instruments experience decreased cyclic fatigue resistance when operated in canals with coronal- and middle-third curvatures when compared with curvatures in the apical-third. Instrumenting coronally positioned curvatures with reciprocating files needs to be performed with caution. CLINICAL RELEVANCE The location of the root canal's curvature influences the fracture resistance of rotary files that are used with reciprocating movements. Therefore, caution needs to be exercised when using reciprocating instruments in canals with coronal or middle curvatures.
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Affiliation(s)
- Tyler Sobotkiewicz
- Division of Endodontics, Faculty of Dentistry, The University of British Columbia (UBC), 2199 Wesbrook Mall, Vancouver, V6T1Z3, Canada
| | - Xiangya Huang
- Department of Conservative Dentistry & Endodontics, Guanghua School of Stomatology, Guangdong Province Key Laboratory of Stomatology, Sun Yat-Sen University Guangzhou, Guangzhou, China
| | - Markus Haapasalo
- Division of Endodontics, Faculty of Dentistry, The University of British Columbia (UBC), 2199 Wesbrook Mall, Vancouver, V6T1Z3, Canada
| | | | - Ahmed Hieawy
- Division of Endodontics, Faculty of Dentistry, The University of British Columbia (UBC), 2199 Wesbrook Mall, Vancouver, V6T1Z3, Canada
| | - Jinghao Hu
- Division of Endodontics, Faculty of Dentistry, The University of British Columbia (UBC), 2199 Wesbrook Mall, Vancouver, V6T1Z3, Canada
| | - Huimin Zhou
- Center for Biomedical Materials and Engineering, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin, China
| | - Zhejun Wang
- Division of Endodontics, Faculty of Dentistry, The University of British Columbia (UBC), 2199 Wesbrook Mall, Vancouver, V6T1Z3, Canada
| | - Ya Shen
- Division of Endodontics, Faculty of Dentistry, The University of British Columbia (UBC), 2199 Wesbrook Mall, Vancouver, V6T1Z3, Canada.
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17
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El Feky HM, Ezzat KM, Bedier MMA. Cyclic fatigue resistance of M-Pro and RaCe Ni-Ti rotary endodontic instruments in artificial curved canals: a comparative in vitro study. Restor Dent Endod 2019; 44:e44. [PMID: 31799171 PMCID: PMC6875542 DOI: 10.5395/rde.2019.44.e44] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 09/18/2019] [Accepted: 09/24/2019] [Indexed: 11/18/2022] Open
Abstract
Objectives To compare the flexural cyclic fatigue resistance and the length of the fractured segments (FLs) of recently introduced M-Pro rotary files with that of RaCe rotary files in curved canals and to evaluate the fracture surface by scanning electron microscopy (SEM). Materials and Methods Thirty-six endodontic files with the same tip size and taper (size 25, 0.06 taper) were used. The samples were classified into 2 groups (n = 18): the M-Pro group (M-Pro IMD) and the RaCe group (FKG). A custom-made simulated canal model was fabricated to evaluate the total number of cycles to failure and the FL. SEM was used to examine the fracture surfaces of the fragmented segments. The data were statistically analyzed and comparisons between the 2 groups for normally distributed numerical variables were carried out using the independent Student's t-test. A p value less than 0.05 was considered to indicate statistical significance. Results The M-Pro group showed significantly higher resistance to flexural cyclic fatigue than the RaCe group (p < 0.05), but there was no significant difference in the FLs between the 2 groups (p ≥ 0.05). Conclusions Thermal treatment of nickel-titanium instruments can improve the flexural cyclic fatigue resistance of rotary endodontic files, and the M-Pro rotary system seems to be a promising rotary endodontic file.
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18
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Scott R, Arias A, Macorra JC, Govindjee S, Peters OA. Resistance to cyclic fatigue of reciprocating instruments determined at body temperature and phase transformation analysis. AUST ENDOD J 2019; 45:400-406. [DOI: 10.1111/aej.12374] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2019] [Indexed: 10/25/2022]
Affiliation(s)
- Raymond Scott
- Department of Endodontics University of the Pacific Arthur A. Dugoni School of Dentistry San Francisco California USA
| | - Ana Arias
- Department of Endodontics University of the Pacific Arthur A. Dugoni School of Dentistry San Francisco California USA
- Department of Conservative Dentistry and Prothesis School of Dentistry Complutense University Madrid Spain
| | - José C. Macorra
- Department of Conservative Dentistry and Prothesis School of Dentistry Complutense University Madrid Spain
| | - Sanjay Govindjee
- Department of Civil and Environmental Engineering University of California Berkeley California USA
| | - Ove A. Peters
- Department of Endodontics University of the Pacific Arthur A. Dugoni School of Dentistry San Francisco California USA
- Oral Health Centre University of Queensland Herston Queensland Australia
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19
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Hülsmann M, Donnermeyer D, Schäfer E. A critical appraisal of studies on cyclic fatigue resistance of engine-driven endodontic instruments. Int Endod J 2019; 52:1427-1445. [PMID: 31267579 DOI: 10.1111/iej.13182] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 06/30/2019] [Indexed: 11/29/2022]
Abstract
The endodontic literature contains a plethora of studies on static and dynamic cyclic fatigue resistance tests performed on a large array of rotary or reciprocating nickel-titanium endodontic instruments. It was the aim of this review to summarize the currently available evidence to point out the different outcomes from static versus dynamic tests and to assess whether cyclic fatigue tests provide useful data and information for clinical practice. An electronic literature research in the database PubMed was performed using appropriate search terms, and the titles and abstract were screened for relevance. Language was restricted to English. The review reveals marked differences between the results obtained in static and dynamic tests, and also, the results for the same instruments assessed either under static or dynamic experimental conditions are widely inconsistent. Between the lowest and the highest value for one and the same pathfinding instrument was a factor of about 123 when cyclic fatigue was assessed either under static or dynamic experimental conditions. Moreover, standard deviations of up to 30% have been reported. Environmental temperature has a 500% impact on the lifetime of instruments. In conclusion, fatigue resistance tests conducted under room temperature should be regarded as having little meaning and the scientific and clinical benefits of fatigue resistance tests are very limited. These data should be provided by the manufacturer of the instruments.
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Affiliation(s)
- M Hülsmann
- Department of Preventive Dentistry, Periodontology and Cariology, University Medicine Göttingen (UMG), Göttingen, Germany
| | - D Donnermeyer
- Department of Periodontology and Operative, Westphalian Wilhelms-University, Münster, Germany
| | - E Schäfer
- Central Interdisciplinary Ambulance, Westphalian Wilhelms-University, Münster, Germany
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20
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In vitro comparison of cyclic fatigue resistance of two rotary single-file endodontic systems: OneCurve versus OneShape. Odontology 2018; 107:196-201. [DOI: 10.1007/s10266-018-0390-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 09/11/2018] [Indexed: 10/28/2022]
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21
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Barbosa I, Ferreira F, Scelza P, Neff J, Russano D, Montagnana M, Zaccaro Scelza M. Defect propagation in NiTi rotary instruments: a noncontact optical profilometry analysis. Int Endod J 2018; 51:1271-1278. [DOI: 10.1111/iej.12936] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 04/03/2018] [Indexed: 11/29/2022]
Affiliation(s)
- I. Barbosa
- Department of Endodontics; Fluminense Federal University (UFF); Niteroi RJ Brazil
| | - F. Ferreira
- Department of Endodontics; Fluminense Federal University (UFF); Niteroi RJ Brazil
| | - P. Scelza
- Department of Endodontics; Fluminense Federal University (UFF); Niteroi RJ Brazil
| | - J. Neff
- ZYGO Corporation; Middlefield CT USA
| | | | | | - M. Zaccaro Scelza
- Department of Endodontics; Fluminense Federal University (UFF); Niteroi RJ Brazil
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22
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Cyclic Fatigue Resistance of Heat-treated Nickel-titanium Instruments after Immersion in Sodium Hypochlorite and/or Sterilization. J Endod 2018; 44:648-653. [DOI: 10.1016/j.joen.2017.12.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 11/24/2017] [Accepted: 12/17/2017] [Indexed: 11/17/2022]
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23
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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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24
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Fatigue Resistance of a 3-dimensional Conforming Nickel-Titanium Rotary Instrument in Double Curvatures. J Endod 2016; 42:961-4. [DOI: 10.1016/j.joen.2016.02.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 02/25/2016] [Accepted: 02/25/2016] [Indexed: 11/27/2022]
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25
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WaveOne Rotary Instruments after Clinical Use. J Endod 2016; 42:186-9. [DOI: 10.1016/j.joen.2015.10.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 10/09/2015] [Accepted: 10/13/2015] [Indexed: 11/18/2022]
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26
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Brito-Júnior M, Silva-Sousa YTC, Bruniera JFB, Camilo CC, Faria-E-Silva AL, Saquy PC. Obturation over an S1 ProTaper instrument fragment in a mandibular molar with three years of follow-up. Braz Dent J 2015; 25:571-5. [PMID: 25590208 DOI: 10.1590/0103-6440201302436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Accepted: 10/21/2014] [Indexed: 11/22/2022] Open
Abstract
This case report describes root canal filling performed over a large S1 ProTaper file fragment in a second mandibular molar with irreversible pulpitis. An S1 ProTaper file was fractured during the instrumentation of the mesiobuccal canal. Approximately 10 mm of file fragment remained in the apical and middle thirds of the canal. The obturation was performed over this fragment using thermomechanically compacted gutta-percha and sealer. Radiographic findings and the absence of clinical signs and symptoms at 3-year follow up indicated successful treatment. Cone-beam computed tomography images revealed absence of periapical lesion and details of intracanal file fragment related to root fillings and apex morphology. In this case, the presence of a large intracanal fractured instrument did not have a negative impact on the endodontic prognosis during the follow up evaluation period.
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Affiliation(s)
- Manoel Brito-Júnior
- Department of Dentistry, UNIMONTES - State University of Montes Claros, Montes Claros, MG, Brazil
| | | | | | - Carla Cristina Camilo
- Department of Dentistry, UNIMONTES - State University of Montes Claros, Montes Claros, MG, Brazil
| | - André Luis Faria-E-Silva
- Department of Dentistry, School of Dentistry, UFS - Federal University of Sergipe, Aracaju, SE, Brazil
| | - Paulo César Saquy
- Department of Dentistry, UNIMONTES - State University of Montes Claros, Montes Claros, MG, Brazil
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27
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Plotino G, Grande NM, Porciani PF. Deformation and fracture incidence of Reciproc instruments: a clinical evaluation. Int Endod J 2014; 48:199-205. [PMID: 24754602 DOI: 10.1111/iej.12302] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 04/20/2014] [Indexed: 02/06/2023]
Abstract
AIM To investigate the incidence of fracture and deformation observed on Reciproc instruments after clinical use. METHODOLOGY A total of 1696 Reciproc NiTi instruments that were discarded after normal clinical usage over 30 months were collected. Of these 1580 instruments were R25 (93%), 76 were R40 (5%), and 40 were R50 (2%). The treatments included 3780 root canal preparations, 3023 primary treatments and 757 retreatments. Root canal preparation was standardized and followed the manufacturer's directions for the use of Reciproc files without creating prior glide path with hand instruments. In retreatment cases, Reciproc R25 instrument was used to remove all filling material and to complete the preparation. Each instrument was used for shaping only one tooth. All the instruments used were inspected under a microscope to detect signs of fracture or deformation and, if any fracture existed, the length of the files was measured. Data were analysed using a chi-square test with a level of significance set at P < .05. RESULTS A total of 8 Reciproc R25 instruments fractured during treatment, which represents 0.47% of the number of instruments used and 0.21% of the root canals treated. Five instruments fractured in primary treatment cases and three instruments during retreatments. Six Reciproc R25 deformed during clinical use (0.35% of the number of instruments used and 0.15% of the root canals treated), four during retreatments and two during primary treatments. The deformation reported was unwinding of the blades, one at 1 mm from the tip and five between 2 and 3 mm from the tip. No deformations or fracture were registered for the Reciproc R40 and R50 instruments. CONCLUSIONS Root canal instrumentation following the manufacturer's instructions can be performed with Reciproc instruments with a very low incidence of instrument fracture and deformation.
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Affiliation(s)
- G Plotino
- Private Practice, Grande, Plotino & Torsello - Studio di Odontoiatria, Rome, Italy
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28
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Bulem ÜK, Kececi AD, Guldas HE. Experimental evaluation of cyclic fatigue resistance of four different nickel-titanium instruments after immersion in sodium hypochlorite and/or sterilization. J Appl Oral Sci 2014; 21:505-10. [PMID: 24473715 PMCID: PMC3891273 DOI: 10.1590/1679-775720130083] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 08/12/2013] [Indexed: 11/30/2022] Open
Abstract
NiTi instruments have a high risk of separation due to torsional or flexural fatigue
(cyclic fatigue). Chemomechanical preparation, cleaning procedures, chemical
disinfection and sterilization cause the corrosion of endodontic instruments that may
weaken the fracture resistance of the instruments.
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Effect of Fatigue on Torsional Failure of Nickel-Titanium Controlled Memory Instruments. J Endod 2014; 40:562-5. [DOI: 10.1016/j.joen.2013.12.035] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Revised: 12/19/2013] [Accepted: 12/30/2013] [Indexed: 11/22/2022]
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Shen Y, Zhou H, Campbell L, Wang Z, Wang R, Du T, Haapasalo M. Fatigue and nanomechanical properties of K3XF nickel-titanium instruments. Int Endod J 2014; 47:1160-7. [DOI: 10.1111/iej.12265] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 02/06/2014] [Indexed: 11/26/2022]
Affiliation(s)
- Y. Shen
- Division of Endodontics; Department of Oral Biological and Medical Sciences; Faculty of Dentistry; The University of British Columbia; Vancouver BC Canada
- Department of Materials Engineering; The University of British Columbia; Vancouver BC Canada
| | - H. Zhou
- Center for Biomedical Materials and Engineering; College of Material Science and Chemical Engineering; Harbin Engineering University; Harbin China
| | - L. Campbell
- Division of Endodontics; Department of Oral Biological and Medical Sciences; Faculty of Dentistry; The University of British Columbia; Vancouver BC Canada
| | - Z. Wang
- Division of Endodontics; Department of Oral Biological and Medical Sciences; Faculty of Dentistry; The University of British Columbia; Vancouver BC Canada
| | - R. Wang
- Department of Materials Engineering; The University of British Columbia; Vancouver BC Canada
| | - T. Du
- Department of Stomatology; Tongji Hospital; Tongji Medical College; Huazhong University of Science and Technology; Wuhan China
| | - M. Haapasalo
- Division of Endodontics; Department of Oral Biological and Medical Sciences; Faculty of Dentistry; The University of British Columbia; Vancouver BC Canada
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Setzer FC, Böhme CP. Influence of combined cyclic fatigue and torsional stress on the fracture point of nickel-titanium rotary instruments. J Endod 2013; 39:133-7. [PMID: 23228273 DOI: 10.1016/j.joen.2012.10.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Revised: 09/26/2012] [Accepted: 10/02/2012] [Indexed: 01/12/2023]
Abstract
INTRODUCTION The combined influence of cyclic fatigue and torsional stress on rotary nickel-titanium instruments has been little investigated. The aim of this study was to determine possible differences in the fracture point of rotary nickel-titanium instruments depending on the application of cyclic fatigue only (CO) or in combination with torsional stress (CT). METHODS A novel custom-designed testing device was constructed. The device used a 2-pin design to test files under cyclic fatigue stress and allowed the additional application of defined torsional stress to the lateral aspect of the file by cutting into a dentin block. Files were tested dynamically at an amplitude of 2 mm at 0.0625 Hz using a programmable computer-controlled system. Three rotary NiTi systems were tested at 30° under CO or CT (with an added 1-Ncm torsional load): Revo-S (Micro-Mega, Besancon, France), Vortex (Dentsply, York, PA), and Profile (Dentsply) of tip sizes 25 and 35. For each file type, 10 new files 25 mm in length with a 0.04 taper size were tested. A total of 120 files were tested: 60 for CO and 60 for CT. The mean fragment length (MFL [in millimeters from the shaft to the fracture point]) was measured under 10× magnification with an electronic gauge to assess the location of the fracture. One-way analysis of variance, the Tukey Honestly Significant Differenct (HSD) test, and the Student's t test for paired samples were used for statistical analysis. RESULTS All fractures, regardless if CO or CT was used, occurred within the area of the curvature. The addition of a torsional load (CT) resulted in a mean 1.09-mm statistically significant difference between CO and CT (P < .0001, CO MFL = 17.78 mm [standard deviation ± 1.08 mm, n = 60]; CT MFL = 16.69 mm [SD ± 0.54 mm, n = 60]), relocating the fracture point toward the area where torsional load was applied. There was a statistically significant difference between the 3 file systems when they were tested either in the CO mode (P < .01) or the CT mode (P < .05). Statistically significant differences also existed for both instrument sizes (ie, 25 [P < .01] and 35 [P < .0001]). CONCLUSIONS CT compared with CO resulted in statistically significantly different MFLs. All fractures remained within the area of the curvature, but with the addition of a torsional load, the location of the fracture moved in the direction of the additionally applied torsional stress. This suggests that stress was distributed from the area in which the torsional load was applied toward the area undergoing cyclic fatigue.
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Affiliation(s)
- Frank C Setzer
- Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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Haapasalo M, Shen Y. Evolution of nickel-titanium instruments: from past to future. ACTA ACUST UNITED AC 2013. [DOI: 10.1111/etp.12049] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ungerechts C, Bårdsen A, Fristad I. Instrument fracture in root canals - where, why, when and what? A study from a student clinic. Int Endod J 2013; 47:183-90. [PMID: 23710943 DOI: 10.1111/iej.12131] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 04/21/2013] [Indexed: 12/22/2022]
Abstract
AIM To investigate the incidence of instrument fracture during nonsurgical root canal treatment performed by undergraduate dental students and to assess the outcome of the treatment if the remaining fragment was left or removed from the root canal. METHODOLOGY A retrospective analysis was performed by reviewing assessment forms (n = 3854) filled out for each root canal treatment over a 10-year period (1997-2006) at the University of Bergen, Norway. Based on the assessment forms, all instrument fractures and data concerning type and dimension of the fractured instruments were identified. Moreover, the affected tooth, root, root curvature and the vertical level of the fragment in the root canal were recorded. To assess the outcome of the root canal treatment, radiographs taken at follow-ups were evaluated by two individual examiners. RESULTS The overall incidence of instrument fracture during the period was 1.0% on a tooth level. Instrument fracture occurred significantly more often in molars and in teeth rated as difficult preoperatively. Of all instrument fractures, 39.5% were located in the mesio-buccal canals of molars, and 76.5% of the fragments were located apically. A significant high percentage of instruments of small apical diameter (sizes 006-015) fractured in relative straight root canals. The treatment was successful in 71.4% of the cases where the instrument fragment was removed, but only in 56.5% of the cases where the fragment remained in the root canal. Significantly more instruments were removed from teeth with a primary infection (P ≤ 0.05). The success rate for teeth with instrument fracture was 72.7% for vital teeth, 58.3% for primary infected teeth and 42.9% in retreatment cases. CONCLUSIONS Within the limits of the present study, the results indicate that the preoperative diagnosis is important for the final treatment outcome and that removal of the fragment is important in cases with primary infection.
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Affiliation(s)
- C Ungerechts
- Department of Clinical Dentistry-Endodontics, University of Bergen, Bergen, Norway
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Shen Y, Zhou HM, Wang Z, Campbell L, Zheng YF, Haapasalo M. Phase transformation behavior and mechanical properties of thermomechanically treated K3XF nickel-titanium instruments. J Endod 2013; 39:919-23. [PMID: 23791264 DOI: 10.1016/j.joen.2013.04.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 03/13/2013] [Accepted: 04/03/2013] [Indexed: 02/02/2023]
Abstract
INTRODUCTION The bending and torsional properties of thermomechanically treated K3XF (SybronEndo, Orange, CA) nickel-titanium instruments in relation to their phase transformation behavior were evaluated. METHODS NiTi instruments K3 (SybronEndo) and K3XF, both in sizes 25/.04 and 40/.04, were examined by differential scanning calorimetry and X-ray diffraction. The metal composition was determined by scanning electron microscopy with X-ray energy-dispersive spectrometric analyses. The bending property of K3 and K3XF instruments was measured in a cantilever-bending test with a maximum deflection of 4.00 mm. A torsional test of the instruments was evaluated according to the American National Standards Institute/American Dental Association Specification No. 28. RESULTS K3 and K3XF instruments had approximately the same chemical composition with a nickel content of 48-49 atomic %. The differential scanning calorimetry analyses showed that each segment of the K3XF instruments (24.89°C ± 1.98°C) had a higher austenite finish temperature than the K3 instruments (17.63°C ± 1.76°C) (P < .05). The bending load values were significantly lower for K3XF than for K3 in the superelastic ranges (P < .05). There was no statistically significant difference between K3 and K3XF in the maximum torque or maximum angular deflection before failure. The torque at fracture values of K3 and K3XF increased significantly with the diameter (P < .05). CONCLUSIONS K3XF exhibited different phase transformation behavior and flexibility when compared with K3, which may be attributed to the special heat treatment history of K3XF instruments.
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Affiliation(s)
- Ya Shen
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, Canada
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Shen Y, Zhou HM, Zheng YF, Peng B, Haapasalo M. Current Challenges and Concepts of the Thermomechanical Treatment of Nickel-Titanium Instruments. J Endod 2013; 39:163-72. [DOI: 10.1016/j.joen.2012.11.005] [Citation(s) in RCA: 294] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 11/03/2012] [Accepted: 11/06/2012] [Indexed: 11/17/2022]
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Shen Y, Coil JM, Zhou H, Zheng Y, Haapasalo M. HyFlex nickel-titanium rotary instruments after clinical use: metallurgical properties. Int Endod J 2013; 46:720-9. [PMID: 23330612 DOI: 10.1111/iej.12049] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 12/12/2012] [Indexed: 12/30/2022]
Abstract
AIM To analyse the type and location of defects in HyFlex CM instruments after clinical use in a graduate endodontic programme and to examine the impact of clinical use on their metallurgical properties. METHODOLOGY A total of 468 HyFlex CM instruments discarded from a graduate endodontic programme were collected after use in three teeth. The incidence and type of instrument defects were analysed. The lateral surfaces of the defect instruments were examined by scanning electron microscopy. New and clinically used instruments were examined by differential scanning calorimetry (DSC) and x-ray diffraction (XRD). Vickers hardness was measured with a 200-g load near the flutes for new and clinically used axially sectioned instruments. Data were analysed using one-way anova or Tukey's multiple comparison test. RESULTS Of the 468 HyFlex instruments collected, no fractures were observed and 16 (3.4%) revealed deformation. Of all the unwound instruments, size 20, .04 taper unwound the most often (n = 5) followed by size 25, .08 taper (n = 4). The trend of DSC plots of new instruments and clinically used (with and without defects) instruments groups were very similar. The DSC analyses showed that HyFlex instruments had an austenite transformation completion or austenite-finish (Af ) temperature exceeding 37 °C. The Af temperatures of HyFlex instruments (with or without defects) after multiple clinical use were much lower than in new instruments (P < 0.05). The enthalpy values for the transformation from martensitic to austenitic on deformed instruments were smaller than in the new instruments at the tip region (P < 0.05). XRD results showed that NiTi instruments had austenite and martensite structure on both new and used HyFlex instruments at room temperature. No significant difference in microhardness was detected amongst new and used instruments (with and without defects). CONCLUSIONS The risk of HyFlex instruments fracture in the canal is very low when instruments are discarded after three cases of clinical use. New HyFlex instruments were a mixture of martensite and austenite structure at body temperature. Multiple clinical use caused significant changes in the microstructural properties of HyFlex instruments. Smaller instruments should be considered as single-use.
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Affiliation(s)
- Y Shen
- Division of Endodontics, Department of Oral Biological & Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, BC, Canada
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Yamazaki-Arasaki AK, Cabrales RJS, Kleine BM, Araki AT, Dos Santos M, Prokopowitsch I. Qualitative analysis of files of four different rotary systems, before and after being used for the twelfth time. Microsc Res Tech 2012; 76:79-85. [PMID: 23108940 DOI: 10.1002/jemt.22139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2011] [Accepted: 09/22/2012] [Indexed: 11/08/2022]
Abstract
The aim of this study was to make a comparative evaluation of the surface topography of the cervical third and tip of four different rotary systems, before and after being used 12 times, in resin blocks with simulated root canals with standardized 45° curvatures, and analyzed by scanning electronic microscopy (SEM). A total of 1,440 resin blocks with simulated root canals and standardized curvatures were used. The blocks were divided into four groups and prepared by the crown down technique according to the manufacturers' recommendations: Group 1 (G1)--K3®, Group 2 (G2)--Protaper Universal®, Group 3 (G3)--Twisted Files®, and Group 4 (G4)--Biorace®. After each preparation, the instruments were washed and autoclaved. A total of 24 instruments were selected, being three new instruments and three after having been used for the 12th time, from each group. These instruments were analyzed by SEM. To perform the evaluation, 24 micrographs were observed by 12 evaluators who attributed a score to the images according to a template. In the qualitative analysis of the cervical region and tip of new instruments, it was observe that the files of Groups G4 and G2 were the least rough and those of G1, the roughest. In the same manner, the cervical region of the instruments was qualitatively analyzed after the 12th time of using them, and there was no statistically significant difference at a level of 1% (ANOVA P < 0.01) between G2 and G4 as well as between G1 and G3. As regards the tip, it was observed that there was no statistically significant difference, at a level of 1%, between the groups: G1 and G3, G1 and G4, and between G3 and G4, and there was statistically significant difference at a level of 1%, between group G2 and the other groups, with G3 having the greatest roughness (ANOVA P < 0.01).
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Shen Y, Coil JM, Zhou HM, Tam E, Zheng YF, Haapasalo M. ProFile Vortex instruments after clinical use: a metallurgical properties study. J Endod 2012; 38:1613-7. [PMID: 23146647 DOI: 10.1016/j.joen.2012.09.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 09/19/2012] [Accepted: 09/24/2012] [Indexed: 11/18/2022]
Abstract
INTRODUCTION The aim of the study was to analyze the incidence and mode of ProFile Vortex instrument (Dentsply Tulsa Dental Specialties, Tulsa, OK) defects during a predefined schedule of clinical use by the undergraduate students in a dental school setting and to examine the metallurgical characteristics of unused and clinically used Vortex instruments. METHODS A total of 2,203 ProFile Vortex instruments discarded after single use from the undergraduate students program over 24 months were collected and examined for defects using a stereomicrosocpe at 10× magnification. The incidence and type of instrument defects or separation were analyzed. The lateral surfaces of part of the defected instruments and fracture surfaces of fractured files were examined using scanning electron microscopy. Unused and clinically used files were examined by differential scanning calorimetry and X-ray diffraction. Vickers hardness of the files was measured with a 200-g load. RESULTS Only 1 of the 2,203 files fractured during clinical use. The cause of fracture was shear stress, and the file also showed unwinding of the helix structure. None of the remaining 2,202 files exhibited unwinding after clinical use. Blunt apicals were detected in 86 used files (3.9%). Austenite-finish temperatures were very similar for as-received, used files with defects and used files without defects, all exceeding 50°C. No difference in microhardness was detected among these 3 instrument groups. X-ray diffraction results showed that NiTi files had austenite structure at room temperature. CONCLUSIONS The risk of ProFile Vortex fracture is very low when files are used 1 time by undergraduate students. Unwinding of the files was not detected except for the fractured file. Clinical single use had no detectable effect on austenite-martensite phase transformation of the files. Unused and clinical single-use files contain a similar phase structure at body temperature.
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Affiliation(s)
- Ya Shen
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, Canada
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Plotino G, Testarelli L, Al-Sudani D, Pongione G, Grande NM, Gambarini G. Fatigue resistance of rotary instruments manufactured using different nickel–titanium alloys: a comparative study. Odontology 2012; 102:31-5. [DOI: 10.1007/s10266-012-0088-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 09/13/2012] [Indexed: 11/30/2022]
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dos Santos M, Gavini G, Siqueira EL, da Costa C. Effect of Nitrogen Ion Implantation on the Flexibility of Rotary Nickel-Titanium Instruments. J Endod 2012; 38:673-5. [DOI: 10.1016/j.joen.2012.01.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 01/13/2012] [Accepted: 01/30/2012] [Indexed: 10/28/2022]
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Plotino G, Costanzo A, Grande NM, Petrovic R, Testarelli L, Gambarini G. Experimental Evaluation on the Influence of Autoclave Sterilization on the Cyclic Fatigue of New Nickel-Titanium Rotary Instruments. J Endod 2012; 38:222-5. [DOI: 10.1016/j.joen.2011.10.017] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 10/11/2011] [Accepted: 10/16/2011] [Indexed: 11/15/2022]
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Shen Y, Qian W, Abtin H, Gao Y, Haapasalo M. Effect of environment on fatigue failure of controlled memory wire nickel-titanium rotary instruments. J Endod 2012; 38:376-80. [PMID: 22341078 DOI: 10.1016/j.joen.2011.12.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2011] [Revised: 11/30/2011] [Accepted: 12/04/2011] [Indexed: 02/03/2023]
Abstract
INTRODUCTION This study examined the fatigue behavior of 2 types of nickel-titanium (NiTi) instruments made from a novel controlled memory NiTi wire (CM wire) under various environment conditions. METHODS Three conventional superelastic NiTi instruments of ProFile (Dentsply Maillefer, Ballaigues, Switzerland), Typhoon (Clinician's Choice Dental Products, New Milford, CT), and DS-SS0250425NEYY (Clinician's Choice Dental Products) and 2 new CM wire instruments of Typhoon CM and DS-SS0250425NEYY CM were subjected to rotational bending at the curvature of 35° in air, deionized water, 17% EDTA, or deionized water after immersion in 6% sodium hypochlorite for 25 minutes, and the number of revolutions of fracture (N(f)) was recorded. The fracture surface of all fragments was examined by a scanning electron microscope. The crack-initiation sites and the percentage of dimple area to the whole fracture cross-section were noted. RESULTS Two new CM Wire instruments yielded an improvement of >4 to 9 times in N(f) than conventional NiTi files with the same design under various environments (P < .05). The fatigue life of 3 conventional superelastic NiTi instruments was similar under various environments, whereas the N(f) of 2 new CM Wire instruments was significantly longer in liquid media than in air (P < .05). The vast majority of CM instruments showed multiple crack origins, whereas most instruments made from conventional NiTi wire had one crack origin. The values of the area fraction occupied by the dimple region were significantly smaller on CM NiTi instruments than in conventional NiTi instruments under various environments (P < .05). CONCLUSIONS Within the limitations of this study, the type of NiTi metal alloy (CM files vs conventional superelastic NiTi files) influences the cyclic fatigue resistance under various environments. The fatigue life of CM instruments is longer in liquid media than in air.
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Affiliation(s)
- Ya Shen
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, British Columbia, Canada
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Metallurgical Characterization of Controlled Memory Wire Nickel-Titanium Rotary Instruments. J Endod 2011; 37:1566-71. [DOI: 10.1016/j.joen.2011.08.005] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 07/05/2011] [Accepted: 08/02/2011] [Indexed: 11/19/2022]
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King JB, Roberts HW, Bergeron BE, Mayerchak MJ. The effect of autoclaving on torsional moment of two nickel-titanium endodontic files. Int Endod J 2011; 45:156-61. [DOI: 10.1111/j.1365-2591.2011.01958.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Shen Y, Qian W, Abtin H, Gao Y, Haapasalo M. Fatigue Testing of Controlled Memory Wire Nickel-Titanium Rotary Instruments. J Endod 2011; 37:997-1001. [DOI: 10.1016/j.joen.2011.03.023] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 03/19/2011] [Accepted: 03/25/2011] [Indexed: 11/24/2022]
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Huang HM, Chang WJ, Teng NC, Lin HL, Hsieh SC. Structural analysis of cyclic-loaded nickel-titanium rotary instruments by using resonance frequency as a parameter. J Endod 2011; 37:993-6. [PMID: 21689558 DOI: 10.1016/j.joen.2011.03.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 03/25/2011] [Accepted: 03/25/2011] [Indexed: 10/18/2022]
Abstract
INTRODUCTION The aim of this study was to investigate the relationship between fatigue life and resonance frequency (RF) of various types of nickel-titanium (NiTi) rotary instruments. In addition, the influence of NiTi instruments with different manufacturing methods on cyclic loading was evaluated by using RF as a parameter. METHODS Twenty-eight ProFile instruments and 10 Twisted File instruments were subjected to cyclic fatigue-loading until fracture by repeated preparation with simulated root canals made of clear resin. The RF of each sample was recorded immediately after the simulated canal block was prepared. For each sample, the microscopic images on the fracture surface, change in lengthening deformation, number of canal blocks prepared, and corresponding RF changes were recorded. RESULTS For all the tested instruments, RF values decreased gradually before breakdown when the fatigue failure of the instruments was associated with plastic deformation. In addition, there was a linear relationship between the RF change and the corresponding deformation of the failed instruments. CONCLUSIONS These results demonstrate that the RF analysis has potential as a tool for structural analysis in NiTi instruments.
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Affiliation(s)
- Haw-Ming Huang
- School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan
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Ormiga F, da Cunha Ponciano Gomes JA, de Araújo MCP, Barbosa AOG. An Initial Investigation of the Electrochemical Dissolution of Fragments of Nickel-Titanium Endodontic Files. J Endod 2011; 37:526-30. [DOI: 10.1016/j.joen.2010.12.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 12/02/2010] [Accepted: 12/20/2010] [Indexed: 11/25/2022]
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He R, Ni J. Design Improvement and Failure Reduction of Endodontic Files through Finite Element Analysis: Application to V-Taper File Designs. J Endod 2010; 36:1552-7. [DOI: 10.1016/j.joen.2010.06.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 06/19/2010] [Accepted: 06/20/2010] [Indexed: 11/16/2022]
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Gavini G, Pessoa OF, Barletta FB, Vasconcellos M, Caldeira CL. Cyclic Fatigue Resistance of Rotary Nickel-Titanium Instruments Submitted to Nitrogen Ion Implantation. J Endod 2010; 36:1183-6. [DOI: 10.1016/j.joen.2010.03.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 03/09/2010] [Accepted: 03/11/2010] [Indexed: 10/19/2022]
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