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La Rosa GRM, Canova FS, Generali L, Pedullà E. The Role of Pecking Motion Depths in Dynamic Cyclic Fatigue Resistance: In Vitro Study. Int Dent J 2024; 74:855-861. [PMID: 38350803 PMCID: PMC11287150 DOI: 10.1016/j.identj.2024.01.014] [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] [Received: 10/10/2023] [Revised: 01/09/2024] [Accepted: 01/22/2024] [Indexed: 02/15/2024] Open
Abstract
OBJECTIVE This is the first study evaluating the impact of different pecking motion depths on dynamic cyclic fatigue resistance of different endodontic instruments. METHODS Four nickel-titanium systems (Hyflex EDM OneFile 25/. ∼; Rotate 25/0.6; Mtwo 25/0.6; Reciproc Blue R25) were tested. Forty instruments from each group were subjected to 4 different pecking movements to evaluate their cyclic fatigue resistance. The distances for the pecking motion were 3-mm forward and backward, 1-mm (3-mm forward and 2-mm backward), 2-mm (4-mm forward and 2-mm backward), and 3-mm (5-mm forward and 2-mm backward). Speeds were 100 and 200 mm/min for the descending and ascending motion, respectively. The times to fracture (TtF) in seconds were recorded for each instrument. Data were statistically analysed by using 2-way ANOVA and Bonferroni multiple comparison post hoc test (P < .05). RESULTS All instruments had a significant increase in cyclic fatigue resistance during the forward dynamic motion compared with the axial continuous. Overall, the heat-treated instruments reported higher fatigue strength than the untreated files (P < .05). Reciproc Blue and Hyflex EDM showed higher TtF in the forward movements of 1-/2-mm and 2-mm (P < .05), respectively while Mtwo 25.06 and Rotate 25.06 in the forward movement of 3-mm (P < .05). CONCLUSIONS Within the limits of this in vitro study, the pecking motion depths had varying impacts on the cyclic fatigue resistance of instruments. Reciproc Blue and Hyflex EDM performed significantly better with pecking motions of 1-and 2-mm. Improving endodontic instrument durability through specific pecking depths has the potential for improving clinical performance and reducing instrument failures.
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Affiliation(s)
- Giusy Rita Maria La Rosa
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy.
| | - Francesco Saverio Canova
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, 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
| | - Eugenio Pedullà
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
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Jeong HY, Ha JH, Sigurdsson A, Peters OA, Kim HC, Kwak SW. Effects of Side Flattening on Torsional and Cyclic Fracture Resistance of Nickel-Titanium File. J Endod 2024; 50:1011-1016. [PMID: 38642733 DOI: 10.1016/j.joen.2024.04.008] [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] [Received: 01/18/2024] [Revised: 04/02/2024] [Accepted: 04/10/2024] [Indexed: 04/22/2024]
Abstract
INTRODUCTION The purpose of this study was to evaluate the effect of side flattening of cutting flutes on the cyclic resistance and torsional resistance of nickel-titanium files. METHODS Both novel flattened Platinum V.EU (PL) and standard nonflattened CC Premium V.EU (CC) rotaries were tested. For cyclic fatigue tests, all the files were rotated in an artificial root canal with a curvature of 45° and a radius of 6.06 mm at 300 rpm (n = 15 in each group). The number of cycles to failure (NCF) was calculated. For torsional tests, the files were rotated at 2 rpm clockwise until fracture occurred. The maximum torque value at fracture was measured and the toughness and distortion angle were computed. Subsequently, 5 fragments were randomly selected in each experiment, the cross-section and longitudinal direction of the fragments were photographed using a scanning electron microscope. An unpaired t-test was performed at a significance level of 95%. RESULTS There was a statistically significant difference in NCF between CC and PL (P < .05). CC showed higher NCF than PL. There was no statistically significant difference between CC and PL with regards to the parameters related to torsional resistance (distortion angle, ultimate strength, and toughness) (P > .05). CONCLUSION Within the limitations of this study, side flattening of the file did not improve cyclic resistance or torsional resistance of the files. As side flattening may reduce a file's cyclic resistance, such files should be used with caution in clinical practice.
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Affiliation(s)
- Hee-Yoon Jeong
- Department of Conservative Dentistry, School of Dentistry, Dental Research Institute, Dental and Life Science Institute, Pusan National University, Yangsan, South Korea
| | - Jung-Hong Ha
- Department of Conservative Dentistry, College of Dentistry, Kyungpook National University, Daegu, South Korea
| | - Asgeir Sigurdsson
- Department of Endodontics, New York University College of Dentistry, New York University, New York, New York
| | - Ove A Peters
- School of Dentistry, The University of Queensland, Herston, Queensland, Australia
| | - Hyeon-Cheol Kim
- Department of Conservative Dentistry, School of Dentistry, Dental Research Institute, Dental and Life Science Institute, Pusan National University, Yangsan, South Korea
| | - Sang Won Kwak
- Department of Conservative Dentistry, School of Dentistry, Dental Research Institute, Dental and Life Science Institute, Pusan National University, Yangsan, South Korea.
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Pedullà E, Carlesi T, Pappalardo A, Canova FS, Malagnino VA, La Rosa GRM, Generali L. Impact of pecking amplitude on cyclic fatigue of new nickel-titanium files. Clin Exp Dent Res 2024; 10:e811. [PMID: 38053521 PMCID: PMC10860459 DOI: 10.1002/cre2.811] [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] [Received: 09/18/2023] [Revised: 10/31/2023] [Accepted: 11/05/2023] [Indexed: 12/07/2023] Open
Abstract
OBJECTIVES The aim of this study is to determine the cyclic fatigue resistance of Mtwo Minimal in static and dynamic tests, with different amplitudes of pecking movements, at intracanal temperature. MATERIALS AND METHODS Two hundred new 25-mm Mtwo Minimal rotary files (#10/0.035, #17.5/0.045, #25/0.05, #40/0.03, #45/0.03) were tested in static and dynamic cyclic fatigue tests at 35°C (±1°C). An artificial stainless-steel canal was used. In the dynamic mode, axial movements were set at 1 and 3 mm. The number of cycles to fracture (NCF) was recorded and statistically analyzed by one-way analysis of variance (p < 0.05). RESULTS The 3-mm dynamic test showed significantly increased NCF than the other tests for the #10/0.035, #17.5/0.045, and #25/0.05 files (p < 0.05). The #40/0.03 and #45/0.03 files showed no significant differences in all the tests (p > 0.05). CONCLUSION Mtwo Minimal showed higher cyclic fatigue resistance in the dynamic test than the static test, except for the larger instruments. The 3-mm pecking amplitude increased the cyclic fatigue resistance of the smaller instruments.
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Affiliation(s)
- Eugenio Pedullà
- Department of General Surgery and Medical‐Surgical SpecialtiesUniversity of CataniaCataniaItaly
| | - Teocrito Carlesi
- Department of Medical, Oral and Biotechnological Sciences, Faculty of Medicine and SurgeryUniversity of Chieti—Pescara “G. D'Annunzio”ChietiItaly
- Department of Innovative Technologies in Medicine and Dentistry, Faculty of Medicine and SurgeryUniversity of Chieti—Pescara “G. D'Annunzio”ChietiItaly
| | | | | | - Vito Antonio Malagnino
- Department of Innovative Technologies in Medicine and Dentistry, Faculty of Medicine and SurgeryUniversity of Chieti—Pescara “G. D'Annunzio”ChietiItaly
| | | | - Luigi Generali
- Department of Surgery, Medicine, Dentistry and Morphological Sciences with Transplant Surgery, Oncology and Regenerative Medicine RelevanceUniversity of Modena and Reggio EmiliaModenaItaly
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La Rosa GRM, Leotta ML, Canova FS, Romeo VR, Cervino G, Generali L, Pedullà E. Cyclic fatigue resistance of different nickel-titanium instruments in single and double curvature at room and body temperatures: A laboratory study. AUST ENDOD J 2023; 49:592-598. [PMID: 37592880 DOI: 10.1111/aej.12789] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 08/07/2023] [Indexed: 08/19/2023]
Abstract
The aim of this study was to compare the cyclic fatigue resistance of nickel-titanium instruments inside single and double-curved canals at different temperatures. 160 HyFlex EDM #20.05 (HEDM), VDW.ROTATE #20.05 and #25.06, Mtwo #25.06 were randomised (n = 10) for the dynamic cyclic fatigue tests according to the curvature (i.e. single and double) at 20° ± 1°C and 35° ± 1°C. The number of cycles to fracture (NCF) was analysed by two-way ANOVA with p < 0.05. Fatigue resistance of all instruments significantly decreased at body temperature in single and double curvatures, except for HEDM in double curvature. The NCF was significantly lower in double curvature than single at both temperatures for all files, except for VDW.ROTATE #20.05 at 35° ± 1°C. Within the study limitations, temperature significantly impaired cyclic fatigue resistance of all files except HEDM #20.05 in double curvature. Similarly, double curvature had a detrimental effect on cyclic fatigue resistance of all files except for VDW.ROTATE #20.05 at body temperature.
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Affiliation(s)
- Giusy Rita Maria La Rosa
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Maria Laura Leotta
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Francesco Saverio Canova
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Virginia Rosy Romeo
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Gabriele Cervino
- Department of Biomedical and Dental Sciences and Morphological and Functional Imaging, Messina University, Messina, Italy
| | - Luigi Generali
- Department of Surgery, Medicine, Dentistry and Morphological Sciences with Transplant Surgery, Oncology and Regenerative Medicine Relevance (CHIMOMO), University of Modena and Reggio Emilia, Modena, Italy
| | - Eugenio Pedullà
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
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Kasuga Y, Kimura S, Maki K, Unno H, Omori S, Hirano K, Ebihara A, Okiji T. Phase transformation and mechanical properties of heat-treated nickel-titanium rotary endodontic instruments at room and body temperatures. BMC Oral Health 2023; 23:825. [PMID: 37904159 PMCID: PMC10614384 DOI: 10.1186/s12903-023-03550-6] [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] [Received: 07/04/2023] [Accepted: 10/18/2023] [Indexed: 11/01/2023] Open
Abstract
BACKGROUND The aim of this study was to evaluate the phase composition, phase transformation temperatures, bending property, and cyclic fatigue resistance of different heat-treated nickel-titanium (NiTi) rotary instruments with the same tip diameter and taper at room (RT; 25 ± 1 °C) and body (BT; 37 ± 1 °C) temperatures. METHODS Five heat-treated NiTi rotary instruments, HyFlex EDM (EDM), HyFlex CM (CM), Vortex Blue (VB), RE file CT (RE) and JIZAI, and a non-heat-treated NiTi rotary instrument (Mtwo) with a size 40, 0.04 taper were investigated. Temperature-dependent phase transformation was examined with differential scanning calorimetry (DSC). The bending loads of the instruments at RT and BT were evaluated using a cantilever-bending test. Cyclic fatigue resistance at RT and BT was measured using a dynamic test, during which the instruments were rotated in combination with a 2-mm back-and-forth motion in an artificial curved canal, and the number of cycles to failure (NCF) was determined. The results were analyzed using two-way repeated measures analysis of variance, a simple main effect test, and the Bonferroni test (α = 0.05). RESULTS DSC results indicated that EDM and Mtwo were primarily composed of martensite/R-phase and austenite, respectively, while the other heat-treated instruments were composed of a mix of martensite/R-phase and austenite at the tested temperatures. Regardless of the temperature setting, the bending loads of heat-treated instruments were significantly lower than those of Mtwo (p < 0.05). EDM showed the lowest bending loads and highest NCF at both temperatures (p < 0.05). CM, VB, and JIZAI showed significantly higher bending loads at BT than at RT (p < 0.05). The NCF of all the heat-treated instruments, except VB, was lower at BT than at RT (p < 0.05). At BT, the NCF of CM, VB, RE, and JIZAI were not significantly higher than that of Mtwo (p > 0.05). CONCLUSIONS Heat-treated NiTi instruments exhibited lower bending loads and higher NCF values than Mtwo. However, this tendency was less pronounced at BT than at RT, especially in the NCF values of instruments with a mixture of martensite/R-phase and austenite phases at the tested temperatures.
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Affiliation(s)
- Yuka Kasuga
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - 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), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.
| | - Keiichiro Maki
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Hayate Unno
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Satoshi Omori
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Keiko Hirano
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Arata Ebihara
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Takashi Okiji
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
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Elsewify T, Elhalabi H, Eid B. Dynamic Cyclic Fatigue and Differential Scanning Calorimetry Analysis of R-Motion. Int Dent J 2023; 73:680-684. [PMID: 36631389 PMCID: PMC10509393 DOI: 10.1016/j.identj.2022.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/14/2022] [Accepted: 12/18/2022] [Indexed: 01/11/2023] Open
Abstract
INTRODUCTION The aim of this study was to assess the dynamic cyclic fatigue resistance of an R-Motion file at simulated body temperature and document corresponding phase transformations compared to OneCurve and HyFlex EDM (HFEDM). METHODS R-Motion (25/.06), OneCurve (25/.06), and HFEDM (25/.06) files were selected and divided into 3 groups (n = 9) according to the file type. Dynamic cyclic fatigue testing was done with a custom-made artificial stainless-steel canal that had a 90° angle of curvature and a 5-mm radius of curvature. Files were operated continuously at body temperature until fracture in the artificial canal. The time to fracture was calculated. Statistical analysis was performed, and significance was set at 5%. Phase transformation temperatures for 2 instruments of each group were analysed by differential scanning calorimetry (DSC) analysis. RESULTS The highest mean time to fracture value was measured in the HFEDM group (277.84 ± 2.51), followed by the R-Motion group (115.09 ± 0.01), whilst the lowest value was found in the OneCurve group (44.28 ± 3.63). Post hoc pairwise comparisons were all statistically significant (P < .001). DSC heating curves show austinite start temperatures to be 33.94 °C and 43.32 °C and austinite finish temperatures to be 35.09 °C and 50 °C for R-Motion and HFEDM, respectively. DSC cooling curves show martensite start temperatures to be 27.54 °C and 44.52 °C and martensite finish temperatures to be 29.13 °C and 37.68 °C for R-Motion and HFEDM, respectively. DSC curves of OneCurve failed to demonstrate transformation temperatures within the tested heat range. CONCLUSIONS Crystalline arrangement of Ni and Ti atoms within the NiTi alloys greatly affects the dynamic cyclic fatigue resistance of the file.
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Affiliation(s)
- Tarek Elsewify
- Endodontic Department, Faculty of Dentistry, Ain Shams University, Cairo, Egypt; Restorative Dental Sciences Department, College of Dentistry, Gulf Medical University, Ajman, UAE.
| | - Hisham Elhalabi
- Endodontic Department, Faculty of Dentistry, Assuit University, Assuit, Egypt
| | - Bassem Eid
- Restorative Dental Sciences Department, College of Dentistry, Gulf Medical University, Ajman, UAE
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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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Unno H, Ebihara A, Hirano K, Kasuga Y, Omori S, Nakatsukasa T, Kimura S, Maki K, Okiji T. Mechanical Properties and Root Canal Shaping Ability of a Nickel-Titanium Rotary System for Minimally Invasive Endodontic Treatment: A Comparative In Vitro Study. MATERIALS (BASEL, SWITZERLAND) 2022; 15:7929. [PMID: 36431416 PMCID: PMC9692467 DOI: 10.3390/ma15227929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/02/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
Selection of an appropriate nickel−titanium (NiTi) rotary system is important for minimally invasive endodontic treatment, which aims to preserve as much root canal dentin as possible. This study aimed to evaluate selected mechanical properties and the root canal shaping ability of TruNatomy (TRN), a NiTi rotary system designed for minimally invasive endodontic shaping, in comparison with existing instruments: HyFlex EDM (HEDM), ProTaper Next (PTN), and WaveOne Gold (WOG). Load values measured with a cantilever bending test were ranked as TRN < HEDM < WOG < PTN (p < 0.05). A dynamic cyclic fatigue test revealed that the number of cycles to fracture was ranked as HEDM > WOG > TRN > PTN (p < 0.05). Torque and vertical force generated during instrumentation of J-shaped artificial resin canals were measured using an automated instrumentation device connected to a torque and vertical force measuring system; TRN exhibited smaller torque and vertical force values in most comparisons with the other instruments. The canal centering ratio for TRN was smaller than or comparable to that for the other instruments except for WOG at the apex level. Under the present experimental conditions, TRN showed higher flexibility and lower torque and vertical force values than the other instruments.
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Influence of different kinematics on stationary and dynamic torsional behavior of JIZAI nickel-titanium rotary instruments: An in vitro study. J Dent Sci 2022. [DOI: 10.1016/j.jds.2022.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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10
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Pedullà E, Canova FS, La Rosa GRM, Naaman A, Diemer F, Generali L, Nehme W. Influence of NiTi Wire Diameter on Cyclic and Torsional Fatigue Resistance of Different Heat-Treated Endodontic Instruments. MATERIALS (BASEL, SWITZERLAND) 2022; 15:6568. [PMID: 36233910 PMCID: PMC9572814 DOI: 10.3390/ma15196568] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/14/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
We compared the mechanical properties of 2Shape mini TS2 (Micro-Mega, Besançon, France) obtained from 1.0 diameter nickel-titanium (NiTi) wires and 2Shape TS2 from 1.2 diameter nickel-titanium (NiTi) wires differently thermally treated at room and body temperature. We used 120 NiTi TS2 1.0 and TS2 1.2 files made from controlled memory (CM) wire and T-wire (n = 10). Cyclic fatigue resistance was tested by recording the number of cycles to fracture (NCF) at room and body temperatures using a customized testing device. Maximum torque and angle of rotation at failure were recorded, according to ISO 3630-1. Data were analyzed by a two-way ANOVA (p < 0.05). The CM-wire files had significantly higher NCFs at both temperatures, independent of wire dimensions. Testing at body temperature negatively affected cyclic fatigue of all files. The 1.0-mm diameter T-wire instruments showed higher NCF than the 1.2-mm diameter, whereas no significant differences emerged between the two CM wires at either temperature. The maximum torque was not significantly different across files. The TS2 CM-wire files showed significantly higher angular rotation to fracture than T-wire files. The TS2 CM-wire prototypes showed higher cyclic fatigue resistance than T-wire prototypes, regardless of wire size, exhibiting suitable torsional properties. Torsional behavior appears to not be affected by NiTi wire size.
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Affiliation(s)
- Eugenio Pedullà
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Via Santa Sofia, 78, 95123 Catania, Italy
| | - Francesco Saverio Canova
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Via Santa Sofia, 78, 95123 Catania, Italy
| | - Giusy Rita Maria La Rosa
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Via Santa Sofia, 78, 95123 Catania, Italy
| | - Alfred Naaman
- Endodontic Department, Saint Joseph University of Beirut, Rue de Damas P.O. Box 17-5208, Beirut 1104 2020, Lebanon
| | - Franck Diemer
- Restorative and Endodontic Department, CHU de Toulouse, University of Toulouse, 31013 Toulouse, France
- Clement Ader Institute, UMR CNRS 5312, 31400 Toulouse, France
| | - Luigi Generali
- Endodontic Section, Department of Surgery, Medicine, Dentistry and Morphological Sciences with Transplant Surgery, Oncology and Regenerative Medicine Relevance (CHIMOMO), School of Dentistry, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Walid Nehme
- Endodontic Department, Saint Joseph University of Beirut, Rue de Damas P.O. Box 17-5208, Beirut 1104 2020, Lebanon
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Pedullà E, Kharouf N, Caruso S, La Rosa GRM, Jmal H, Haikel Y, Mancino D. Torsional, Static and Dynamic Cyclic Fatigue Resistance of Reciprocating and Continuous Rotating NiTi Instruments. J Endod 2022; 48:1421-1427. [PMID: 35987386 DOI: 10.1016/j.joen.2022.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/14/2022] [Accepted: 08/10/2022] [Indexed: 11/17/2022]
Abstract
INTRODUCTION To evaluate torsional, dynamic and static cyclic fatigue resistance of the reciprocating One Reci (OR, Micromega, Besançon, France), WaveOne Gold (WOG, Dentsply Maillefer, Ballaigues, Switzerland), rotary One Curve (OC, MicroMega, Besançon, France) and ProTaper Next X2 (PTN X2, Dentsply Sirona, Ballaigues, Switzerland) instruments. METHODS A total of 120 NiTi instruments (n = 30) OR, WOG, OC and PTN X2 were used. Torque and rotation angle until failure under static torsion loading were measured according to the ISO 3630-1. Static and dynamic fatigue resistance was measured as the time to fracture (TTF) in an artificial stainless-steel canal with a 60° angle and 5-mm radius of curvature at intracanal temperature. The results were analyzed with one-way ANOVA and post-hoc Tukey tests. The alpha-type error was set at 5%. Fracture instruments from torsion and fatigue tests were examined with scanning electron microscope. RESULTS The OR showed higher static fatigue resistance and rotation angle at fracture than the WOG, OC and PTN X2 (P < .05). The WOG exhibited higher torsional resistance than the others (P < .05). Dynamic cyclic fatigue resistance tests had highest TTF than static for the PTN X2 and the WOG groups (P < .05). In the dynamic tests, the OR and WOG showed higher TTF than the OC and PTN X2 (P < .05). CONCLUSIONS Under these experimental condition, One Reci exhibited suitable mechanical properties with the highest cyclic fatigue resistance and angle of rotation among the tested instruments.
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Affiliation(s)
- Eugenio Pedullà
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy.
| | - Naji Kharouf
- Department of Bioengineering and Biomaterials, INSERM (French National Institute of Health and Medical Research) 1121, University of Strasbourg, Strasbourg, France; Department of Endodontics, Faculty of Dental Medicine, University of Strasbourg, Strasbourg, France
| | - Simone Caruso
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Giusy Rita Maria La Rosa
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Hamdi Jmal
- ICube Laboratory, UMR 7357 CNRS, Mechanics Department, University of Strasbourg, Strasbourg, France
| | - Youssef Haikel
- Department of Bioengineering and Biomaterials, INSERM (French National Institute of Health and Medical Research) 1121, University of Strasbourg, Strasbourg, France; Department of Endodontics, Faculty of Dental Medicine, University of Strasbourg, Strasbourg, France
| | - Davide Mancino
- Department of Bioengineering and Biomaterials, INSERM (French National Institute of Health and Medical Research) 1121, University of Strasbourg, Strasbourg, France; Department of Endodontics, Faculty of Dental Medicine, University of Strasbourg, Strasbourg, France
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12
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A Comparative Study of Two Martensitic Alloy Systems in Endodontic Files Carried out by Unskilled Hands. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12126289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The aim of this study was to compare the behavior of two heat-treated file systems on resin blocks in unskilled hands. For this purpose, an in vitro, randomized, cross-sectional study was conducted to compare ProTaper Gold (PTG) with BlueShaper (BS) files. A total of 81 resin blocks were used and analyzed photographically to assess the amount of material removed during instrumentation. PTG removed more material on the outside of the curve in the coronal and apical third, while BS removed more material on the inner part of the curve in the middle third. The procedural errors observed in the total sample were apical transportation (33.8%), blockages (4.9%), ledges (3.7%), and canal perforation. PTG produced more apical transportation, and there were no statistically significant differences between the groups in the formation of ledges, canal perforations, or blockages. No file fractures were recorded during the study. Within the limitations of this study, we can affirm that neither file excessively deformed the artificial canals, and the PTG file produced more apical transportation.
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13
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What meaningful information are the instruments mechanical testing giving us? A comprehensive review. J Endod 2022; 48:985-1004. [PMID: 35667567 DOI: 10.1016/j.joen.2022.05.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 04/21/2022] [Accepted: 05/26/2022] [Indexed: 11/22/2022]
Abstract
Instruments mechanical strength and flexibility are traditionally tested by running cyclic fatigue, torsional, bending, buckling and microhardness tests. Several cyclic fatigue test models have been used in endodontics, all capable of providing a curved trajectory for the instrument to rotate. The cyclic fatigue testing allowed to identify conditions that may affect the fatigue strength outcomes, such as canal radius and degree of curvature, handpiece static vs dynamic motions, test temperature, kinematics, instrument previously wear and sterilization cycles, or instrument's size and metal alloy features. Due to the international test specifications for both torsional and bending tests, the variations of their models are not as many as for cyclic fatigue. These tests have also identified conditions capable of affecting the outcomes, such as kinematics, instrument's preloading, cross-sectional diameters, or alloy heat treatments. Buckling and microhardness are less common, with the metal alloy being considered to have a major influence on the results. Instruments mechanical testing, having all these individual conditions as independent variables, allowed to understand them and moulded the way the technical procedures are performed clinically. Even though the artificiality and simplicity of these tests will hardly mimic real working situations, and independently of being capable of producing cornerstone knowledge, these tests are also associated with inconsistency, lack of reproducibility and low external validity. Several attempts have been made to increase the generalizability of the outcomes by adding test settings that intend to mimic the clinical condition. Although pertinent, these settings may also add variabilities inherent to their concepts and practical applications in the laboratory environment. Although the actual studies should be seen as laboratory mechanical tests that measure very specific parameters under very particular conditions and that by far do not mimic the clinical condition, the lower validity drawback seems to be possible to be minimized when achieving a comprehensive understanding of the instrument behaviour. A Finite Elements Method and/or a multimethod research approach may lead to superior data collection, analysis, and results' interpretation, which when associated with a reliable confounding factors control and proper study designs may be helpful tools and strategies in order to increase the reliability of the outcomes.
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14
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Basturk FB, Özyürek T, Uslu G, Gündoğar M. Mechanical Properties of the New Generation RACE EVO and R-Motion Nickel-Titanium Instruments. MATERIALS 2022; 15:ma15093330. [PMID: 35591664 PMCID: PMC9105925 DOI: 10.3390/ma15093330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/21/2022] [Accepted: 05/03/2022] [Indexed: 12/04/2022]
Abstract
This study aimed to evaluate and compare the dynamic cyclic fatigue, torsional and bending resistance of two novel RACE EVO (FKG Dentaire SA, La Chaux de Fonds, Switzerland) and R-Motion (FKG) nickel−titanium instruments with traditional RaCe (FKG) instruments. RACE EVO, R-Motion and RaCe instruments with a size of 25 and taper of 0.06 were used. A dynamic cyclic fatigue test was used to assess the time to fracture. The fractured surfaces were further analyzed using scanning electron microscopy at ×350 and ×3000 magnifications. A torsional resistance test was performed to measure the maximum torsional strength and angle of rotation. Phase transformations with temperature were evaluated using differential scanning calorimetry. The results were statistically analyzed with a Kruskal−Wallis test at a 5% significance level. R-Motion had the highest time to fracture and the lowest torsional and bending resistance, whereas RaCe had the lowest time to fracture and the highest torsional and bending resistance (p < 0.05). In relation to the angle of rotation, RACE EVO instruments had the highest deformation capacity followed by R-Motion and RaCe instruments (p < 0.05). The greater cyclic fatigue resistance and lower torsional and bending resistance results indicate that the novel R-Motion and RACE EVO instruments are less rigid and more flexible than RaCe instruments.
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Affiliation(s)
- Fatima Betul Basturk
- Department of Endodontics, Istanbul Gelişim University, Istanbul 34310, Turkey
- Correspondence:
| | - Taha Özyürek
- Department of Endodontics, Bahçeşehir University, Istanbul 34734, Turkey;
| | - Gülşah Uslu
- Department of Endodontics, Çanakkale Onsekiz Mart University, Çanakkale 17100, Turkey;
| | - Mustafa Gündoğar
- Department of Endodontics, Istanbul Medipol University, Istanbul 34083, Turkey;
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15
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Schäfer E, Bürklein S, Donnermeyer D. A critical analysis of research methods and experimental models to study the physical properties of NiTi instruments and their fracture characteristics. Int Endod J 2021; 55 Suppl 1:72-94. [PMID: 34862796 DOI: 10.1111/iej.13673] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 12/03/2021] [Indexed: 11/27/2022]
Abstract
The aim of this review is to provide a critical overview of the physical properties (surface hardness, cutting efficiency, bending properties, flexibility and cyclic fatigue resistance) of NiTi instruments. Frequently used experimental models regarding these aspects will be presented and discussed with regard to their strengths and weaknesses. For all these aspects, a plethora of experimental models have been described. Based on a critical appraisal and especially taking the appropriate translation of experimental findings to clinical endodontics into account, suggestions for future research based on clearly defined and valid experimental methodologies will be provided. Up to now, very few attempts have been made to assess which particular physical properties of NiTi instruments exert an impact on the clinical outcome of root canal treatment. Departure from merely focusing on physical properties and fracture characteristics towards more biological aspects in terms of treatment outcome is essential.
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Affiliation(s)
- Edgar Schäfer
- Central Interdisciplinary Ambulance in the School of Dentistry, Münster, Germany
| | - Sebastian Bürklein
- Central Interdisciplinary Ambulance in the School of Dentistry, Münster, Germany
| | - David Donnermeyer
- Department of Periodontology and Operative Dentistry, Westphalian Wilhelms-University, Münster, Germany
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16
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Evaluation of usage-induced degradation of different endodontic file systems. Sci Rep 2021; 11:9027. [PMID: 33907252 PMCID: PMC8079699 DOI: 10.1038/s41598-021-88570-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 04/12/2021] [Indexed: 11/09/2022] Open
Abstract
To evaluate structural profiles and mechanical behaviour of WaveOne Gold (WOG), Twisted File Adaptive (TFA) and XP-endo shaper (XPS) instruments after root canal preparation. Standardized in vitro shaping was performed in presence of 5.25% sodium hypochlorite. File morphology was analyzed using scanning electron microscopy; X-ray diffraction analysis was performed before and after use along with Raman spectroscopy. Nanoindentation was carried out to characterize surface topography. Ni2+ release was measured at 1, 3, 5 and 7 days. X-ray photoelectron spectroscopy (XPS) analysis was done before and after use. After allocating scan line shifts like in WOG, mechanical deformation was shown using first order polynomials. XPS file system showed minimal grooves on surface. SEM of WOG instrument showed scraping surface defects. Hardness varied from 8.11 ± 0.99 GPa in TFA system to 6.7 ± 1.27 GPa and 4.06 ± 4.1 GPa in XPS and WOG. Ni2+ concentration from WOG was 171.2 μg/L. Raman peak at 540-545 cm-1 is attributed to Cr2O3. High resolution of Ti 2p spectrum show distinctive peaks with binding energies dominating in WOG, XPS and TFA file system. XRD exhibited NiTi phases with diffraction peaks. WOG files showed more surface deterioration and less passive layer formation as compared to TFA and XPS systems.
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