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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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Kimura S, Ebihara A, Maki K, Kyaw MS, Kasuga Y, Omori S, Okiji T. Phase transformation behavior and mechanical properties of HyFlex EDM nickel-titanium endodontic rotary instrument: Evaluation at body temperature. J Dent Sci 2024; 19:929-936. [PMID: 38618130 PMCID: PMC11010611 DOI: 10.1016/j.jds.2023.07.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 07/31/2023] [Indexed: 04/16/2024] Open
Abstract
Background/purpose Temperature-dependent phase compositional changes influence the mechanical properties of heat-treated nickel-titanium (NiTi) rotary instruments. This study evaluated the phase composition, bending properties, and cyclic fatigue resistance of HyFlex EDM NiTi rotary instruments against differently heat-treated and non-heat-treated NiTi instruments at body temperature (BT). Materials and methods HyFlex EDM OneFile (EDM) instruments, heat-treated HyFlex CM (CM) and Twisted File (TF) instruments, and non-heat-treated K3 instruments (size #25/.08) were subjected to differential scanning calorimetry, and the martensitic, R-phase, and reverse transformation starting and finishing temperatures were determined. A cantilever bending test and a cyclic fatigue test were conducted at BT (37 °C ± 1.0 °C), and the bending load and number of cycles to failure (NCF) were recorded. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U tests (α = 0.05). Results TF and K3 had reverse transformation finishing temperatures lower than BT, while those for EDM and CM were higher than BT. The bending loads at a 0.5 mm deflection were in the order of EDM < TF < CM < K3 (P < 0.05), and those at a 2.0 mm deflection were EDM < CM and TF < K3 (P < 0.05). EDM had the highest NCF among the four instruments (P < 0.05). Conclusion The EDM instrument had a reverse transformation finishing temperature higher than BT indicating its martensite/R-phase composition at BT. The EDM instrument had superior flexibility and greater resistance to cyclic fatigue than the CM, TF, and K3 instruments at BT.
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Affiliation(s)
- Shunsuke Kimura
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Arata Ebihara
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Keiichiro Maki
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Moe Sandar Kyaw
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Yuka Kasuga
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Satoshi Omori
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Takashi Okiji
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
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Só GB, Siocheta G, Calefi P, Alcalde M, Vivan RR, Duarte MAH, Só MVR, da Rosa RA. Cyclic and torsional fatigue resistance of a new rotary file on a rotary and reciprocating motion. Microsc Res Tech 2023; 86:1635-1641. [PMID: 37587834 DOI: 10.1002/jemt.24399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/17/2023] [Accepted: 08/06/2023] [Indexed: 08/18/2023]
Abstract
This study evaluated the cyclic and torsional fatigue resistance of a new nickel-titanium (Flat File 25.04) instrument on the continuous and reciprocating motion. Sixty instruments of the ProDesign Logic2 25.03 and 25.05 (Easy Equipamentos Odontológicos, Belo Horizonte, Brazil), and MK Flat File 25.04 (n = 20) (MK Life, Porto Alegre, Brazil) were used. For the cyclic fatigue test, an artificial stainless steel simulated canal with an angle of 60° and a radius of curvature of 5 mm located 5 mm from its tip was used. The torque and rotation angle at the instruments' failure on the torsional fatigue test was based on the ISO 3630-1 protocol, in which the 3 mm tip of each instrument was fixed and connected to an electric motor and a load cell. The fractured surface of each fragment was examined by scanning electron microscopy. Data were analyzed using a 1-way analysis of variance and Tukey's test with a significance level of 5%. Flat File 25.04 had lower cyclic fatigue in both kinematics than the Logic instruments (p < .05). Reciprocating motion improved the cyclic fatigue of the tested instruments (p < .05). Flat File 25.04 had similar torque to Logic2 25.05 (p > .05), and both were superior to Logic2 25.03 (p < .05). The angular deflection values were different for the three tested instruments (p < .05), in the decreasing order: Logic2 25.03, 25.05, and Flat File 25.04. Flat File presented good resistance to cyclic and torsional fatigue resistance. Reciprocating motion improved the cyclic fatigue resistance of the instruments and can be considered when using programmable motors. RESEARCH HIGHLIGHTS: Scanning electron microscopy evaluation of different endodontic rotary file and fatigue resistance tests.
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Affiliation(s)
- Gabriel Barcelos Só
- Department of Conservative Dentistry, School of Dentistry, Rio Grande do Sul Federal University (UFRGS), Porto Alegre, Brazil
| | - Giovana Siocheta
- Department of Conservative Dentistry, School of Dentistry, Rio Grande do Sul Federal University (UFRGS), Porto Alegre, Brazil
| | - Pedro Calefi
- Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Murilo Alcalde
- Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Rodrigo Ricci Vivan
- Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Marco Antônio H Duarte
- Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, São Paulo, Brazil
| | - Marcus Vinicius Reis Só
- Department of Conservative Dentistry, School of Dentistry, Rio Grande do Sul Federal University (UFRGS), Porto Alegre, Brazil
| | - Ricardo Abreu da Rosa
- Department of Conservative Dentistry, School of Dentistry, Rio Grande do Sul Federal University (UFRGS), Porto Alegre, Brazil
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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: 0] [Impact Index Per Article: 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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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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Effect of Different Downward Loads on Canal Centering Ability, Vertical Force, and Torque Generation during Nickel-Titanium Rotary Instrumentation. MATERIALS 2022; 15:ma15082724. [PMID: 35454413 PMCID: PMC9031471 DOI: 10.3390/ma15082724] [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: 03/02/2022] [Revised: 03/25/2022] [Accepted: 04/06/2022] [Indexed: 02/04/2023]
Abstract
This study aimed to examine how downward loads influence the torque/force and shaping outcome of ProTaper NEXT (PTN) rotary instrumentation. PTN X1, X2, and X3 were used to prepare J-shaped resin canals employing a load-controlled automated instrumentation and torque/force measuring device. Depending on the torque values, the handpiece was programmed to move as follows: up and down; downward at a preset downward load of 1 N, 2 N or 3 N (Group 1N, 2N, and 3N, respectively; each n = 10); or upward. The torque/force values and instrumentation time were recorded, and the canal centering ratio was calculated. The results were analyzed using a two-way or one-way analysis of variance and the Tukey test (α = 0.05). At the apex level, Group 3N exhibited the least canal deviation among the three groups (p < 0.05). The downward force was Group 3N > Group 2N > Group 1N (p < 0.05). The upward force, representing the screw-in force, was Group 3N > Group 1N (p < 0.05). The total instrumentation time was Group 1N > Group 3N (p < 0.05). In conclusion, increasing the downward load during PTN rotary instrumentation improved the canal centering ability, reduced the instrumentation time, and increased the upward force.
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Kyaw MS, Ebihara A, Maki K, Kimura S, Nakatsukasa T, Htun PH, Thu M, Omori S, Okiji T. Effect of kinematics on the torque/force generation, surface characteristics, and shaping ability of a nickel titanium rotary glide path instrument: an ex-vivo study. Int Endod J 2022; 55:531-543. [PMID: 35263803 DOI: 10.1111/iej.13718] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 03/01/2022] [Accepted: 03/01/2022] [Indexed: 11/30/2022]
Abstract
AIM To evaluate the effect of various rotational motions on the torque/force generation, surface wear, and shaping ability of the ProGlider glide path instrument (Dentsply Sirona). METHODOLOGY Mesiobuccal and mesiolingual canals of mandibular molars were selected based on the canal volume, length, angle of curvature (25°-40°), and radius of curvature (4-8 mm) after micro-computed tomographic scanning. The samples were randomly assigned to four groups (n = 13, each) according to movement kinematics [continuous rotation (CR; 300 rpm), optimum torque reverse motion (OTR; 180° forward and 90° reverse when torque > 0.4 N·cm), time-dependent reciprocal motion (TmR; 180° forward and 90° reverse), and optimum glide path motion (OGP; a combination of 90° forward, 90° reverse, 90° forward, and 120° reverse)]. Instrumentation was performed with an automated root canal instrument and torque/force analysing device. Maximum torque/force values, canal volume changes, and canal-centring ratios at 1, 3, 5, and 7 mm were evaluated. Surface defects (pits, grooves, microcracks, blunt cutting edges, and disruption of cutting edges) and spiral distortion on the ProGlider instrument were scored at the tip and 5 mm short of the tip before and after five consecutive uses with scanning electron microscopy. The Kruskal-Wallis test followed by Dunn's post-test with Bonferroni correction and Wilcoxon signed-rank test were used to analyse the data (α = 0.05). RESULTS OGP generated significantly less clockwise torque and greater upward force than other groups (P < 0.05). OGP resulted in significantly fewer surface defects than CR (P < 0.05). In OGP and CR, the tip exhibited more surface defects than 5 mm short of the tip (P < 0.05). CR resulted in greater volume changes than OGP and TmR (P < 0.05) and greater centring ratios (i.e., more deviation) than OGP at 1 mm and OTR at 3 mm (P < 0.05). CONCLUSIONS Under laboratory conditions using the ProGlider instrument, OGP generated significantly less clockwise torque and greater upward force than the other rotatory motions. OGP generated fewer superficial defects than CR, and the three modes of reciprocal rotation better maintained the apical curvature of root canals than CR with the ProGlider instrument.
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Affiliation(s)
- M S Kyaw
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.,Department of Conservative Dentistry, University of Dental Medicine (Mandalay), Mandalay, Myanmar
| | - A Ebihara
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - K Maki
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - S Kimura
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - T Nakatsukasa
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - P H 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), Tokyo, Japan
| | - M 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), Tokyo, Japan
| | - S Omori
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - T Okiji
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
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Martins JNR, Silva EJNL, Marques D, Pereira MR, Vieira VTL, Arantes-Oliveira S, Martins RF, Braz Fernandes F, Versiani M. Design, Metallurgical Features, and Mechanical Behaviour of NiTi Endodontic Instruments from Five Different Heat-Treated Rotary Systems. MATERIALS 2022; 15:ma15031009. [PMID: 35160955 PMCID: PMC8840527 DOI: 10.3390/ma15031009] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/23/2022] [Accepted: 01/25/2022] [Indexed: 12/24/2022]
Abstract
The current study aimed to compare the F1 endodontic instruments from five different heat-treated rotary systems regarding their design, metallurgical properties, and mechanical performance. Five F1 root canal shaping instruments (ProTaper Gold [PTG], Premium Taper Gold, Go-Taper Flex, EdgeTaper Platinum, and Super Files Blue)—plus, a conventional ProTaper Universal (PTU)—which were evaluated regarding their design, nickel/titanium ratio, phase transformation temperatures, microhardness, cyclic fatigue, and torsional and bending strengths. Mood's median test was used for the statistical comparison with a significance set at 5%. The instruments were similar regarding the nickel/titanium ratio and overall design. Go-Taper Flex had the closest transformation temperatures to PTG. PTU and Go-Taper Flex had the highest microhardness (408.3 and 410.5 HVN). The time to fracture of Super Files Blue was three and seven times higher than PTG and PTU, respectively. No difference was observed in the maximum torque to fracture among PTG (1.30 N·cm) and the other systems, except for the Premium Taper Gold (1.05 N·cm) and Go-Taper Flex (1.10 N·cm). Significantly lower bending loads than PTG (269.2 gf) were observed for the EdgeTaper Platinum (158.3 gf) and Premium Taper Gold (103.5 gf) instruments. Super Files Blue outperformed PTG in the cyclic fatigue test, while EdgeTaper Platinum and Premium Taper Gold were more flexible. Premium Taper Gold and Go-Taper Flex showed lower torsional strength.
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Affiliation(s)
- Jorge N. R. Martins
- Faculdade de Medicina Dentária, Universidade de Lisboa, 1600-277 Lisboa, Portugal; (D.M.); (M.R.P.); (S.A.-O.)
- Grupo de Investigação em Bioquimica e Biologia Oral, Unidade de Investigação em Ciências Orais e Biomédicas (UICOB), 1600-277 Lisboa, Portugal
- Centro de Estudo de Medicina Dentária Baseada na Evidência (CEMDBE), 1600-277 Lisboa, Portugal
- Correspondence:
| | - Emmanuel J. N. L. Silva
- Department of Endodontics, Grande Rio University (UNIGRANRIO), Rio de Janeiro 21210-623, Brazil; (E.J.N.L.S.); (V.T.L.V.)
- Department of Endodontics, Fluminense Federal University, Niterio, Rio de Janeiro 24220-900, Brazil
| | - Duarte Marques
- Faculdade de Medicina Dentária, Universidade de Lisboa, 1600-277 Lisboa, Portugal; (D.M.); (M.R.P.); (S.A.-O.)
- Grupo de Investigação em Bioquimica e Biologia Oral, Unidade de Investigação em Ciências Orais e Biomédicas (UICOB), 1600-277 Lisboa, Portugal
- Centro de Estudo de Medicina Dentária Baseada na Evidência (CEMDBE), 1600-277 Lisboa, Portugal
- LIBPhys-FCT UID/FIS/04559/2013, 1600-277 Lisboa, Portugal
| | - Mário Rito Pereira
- Faculdade de Medicina Dentária, Universidade de Lisboa, 1600-277 Lisboa, Portugal; (D.M.); (M.R.P.); (S.A.-O.)
| | - Victor T. L. Vieira
- Department of Endodontics, Grande Rio University (UNIGRANRIO), Rio de Janeiro 21210-623, Brazil; (E.J.N.L.S.); (V.T.L.V.)
| | - Sofia Arantes-Oliveira
- Faculdade de Medicina Dentária, Universidade de Lisboa, 1600-277 Lisboa, Portugal; (D.M.); (M.R.P.); (S.A.-O.)
- LIBPhys-FCT UID/FIS/04559/2013, 1600-277 Lisboa, Portugal
- BIOMAT, Laboratório de Biomateriais, Unidade de Investigação em Ciências Orais e Biomédicas (UICOB), 1600-277 Lisboa, Portugal
| | - Rui F. Martins
- UNIDEMI, Department of Mechanical and Industrial Engineering, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal;
| | - Francisco Braz Fernandes
- CENIMAT/I3N, Department of Materials Science, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal;
| | - Marco Versiani
- Dental Specialty Center, Brazilian Military Police, Belo Horizonte 30350-190, Brazil;
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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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Cyclic Fatigue Resistance of Blue Heat-Treated Instruments at Different Temperatures. Int J Biomater 2021; 2021:5584766. [PMID: 34373696 PMCID: PMC8349260 DOI: 10.1155/2021/5584766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 06/13/2021] [Accepted: 07/27/2021] [Indexed: 11/17/2022] Open
Abstract
The main aim is to evaluate the cyclic fatigue resistance of blue heat-treated instruments with different kinematics. Twenty-four endodontic instruments of the same brand were used for each of three experimental groups: VB (Vortex Blue 40/0.04), RB (RECIPROC Blue 40/0.06), and XB (X1 Blue 40/0.06). The instruments were randomly distributed and subjected to temperatures of 20°C and 37°C. The fatigue test was performed using a stainless steel device. Data were analysed using the Shapiro-Wilk test, Student's t-test, the F test, and Tukey's and Tamhane tests at significance level P=0.05. The instruments' cyclic fatigue resistance at both temperatures differed significantly for each instrument type (P < 0.001). The RB instruments displayed greater cyclic fatigue resistance at the tested temperatures compared with the VB and XB instruments (P < 0.001). Reciprocating kinematics positively influenced cyclic fatigue resistance. Blue heat-treated instruments showed decreased cyclic fatigue resistance as the temperature increased (P < 0.001).
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Kyaw MS, Ebihara A, Kasuga Y, Maki K, Kimura S, Htun PH, Nakatsukasa T, Okiji T. Influence of rotational speed on torque/force generation and shaping ability during root canal instrumentation of extracted teeth with continuous rotation and optimum torque reverse motion. Int Endod J 2021; 54:1614-1622. [PMID: 33527449 DOI: 10.1111/iej.13485] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 01/26/2021] [Indexed: 01/03/2023]
Abstract
AIM To evaluate how different rotational speeds affect the torque/force generation and shaping ability of rotary root canal instrumentation using JIZAI (MANI, Utsunomiya, Japan) nickel-titanium instruments in continuous rotation and optimum torque reverse (OTR) motion. METHODOLOGY Mesial root canals of extracted mandibular molars were instrumented up to size 25, 0.04 taper using JIZAI instruments, and anatomically matched canals were selected based on geometric features of the canal [canal volume (mm3 ), surface area (mm2 ), length, 15°-20° curvature and radius of curvature (4-8 mm)] after micro-computed tomographic scanning. An automated root canal instrumentation and torque/force analysing device was programmed to permit a simulated pecking motion (2 s downward and 1 s upward at 50 mm min-1 ). The selected canals were prepared with size 25, 0.06 taper JIZAI instruments using continuous rotation or OTR motion and further subdivided according to the rotational speed (300 or 500 rpm, n = 10 each). Real-time clockwise/counterclockwise torque and downward/upward force were recorded using a custom-made torque/force analysing device. Then, the registered pre- and post-operative micro-computed tomographic datasets were examined to evaluate the canal volume changes and centring ratios at 1, 3, 5 and 7 mm from the apical foramen. Data were analysed using two-way analysis of variance or the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni correction (α = 5%). RESULTS Maximum upward force and clockwise torque were significantly smaller in 500 rpm groups than in 300 rpm groups (P < .05); however, no significant difference was found between continuous rotation and OTR motion (P > .05). OTR motion developed higher maximum counterclockwise torque than continuous rotation (P < .05). Maximum downward force, canal volume changes and centring ratios were not significantly different among all groups (P > .05). There was no file fracture in any of the groups. CONCLUSIONS Under laboratory conditions using JIZAI instruments, a rotational speed of 500 rpm generated significantly lower maximum screw-in forces and torque values than rotational speed of 300 rpm. Continuous rotation and OTR motion performed similarly in shaping the canals.
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Affiliation(s)
- M S Kyaw
- Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.,Department of Conservative Dentistry, University of Dental Medicine (Mandalay), Mandalay, Myanmar
| | - A Ebihara
- Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Y Kasuga
- Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - K Maki
- Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - S Kimura
- Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - P H Htun
- Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - T Nakatsukasa
- Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - T Okiji
- Division of Oral Health Sciences, Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
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Nagendrababu V, Murray PE, Ordinola-Zapata R, Peters OA, Rôças IN, Siqueira JF, Priya E, Jayaraman J, Pulikkotil SJ, Suresh N, Dummer PMH. PRILE 2021 guidelines for reporting laboratory studies in Endodontology: explanation and elaboration. Int Endod J 2021; 54:1491-1515. [PMID: 33982298 DOI: 10.1111/iej.13565] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 05/10/2021] [Indexed: 12/11/2022]
Abstract
Guidance to authors is needed to prevent their waste of talent, time and resources in writing manuscripts that will never be published in the highest-quality journals. Laboratory studies are probably the most common type of endodontic research projects because they make up the majority of manuscripts submitted for publication. Unfortunately, most of these manuscripts fail the peer-review process, primarily due to critical flaws in the reporting of the methods and results. Here, in order to guide authors, the Preferred Reporting Items for study Designs in Endodontology (PRIDE) team developed new reporting guidelines for laboratory-based studies: the Preferred Reporting Items for Laboratory studies in Endodontology (PRILE) 2021 guidelines. The PRILE 2021 guidelines were developed exclusively for the area of Endodontology by integrating and adapting the modified CONSORT checklist of items for reporting in vitro studies of dental materials and the Clinical and Laboratory Images in Publications (CLIP) principles. The process of developing the PRILE 2021 guidelines followed the recommendations of the Guidance for Developers of Health Research Reporting Guidelines. The aim of the current document is to provide authors with an explanation for each of the items in the PRILE 2021 checklist and flowchart with examples from the literature, and to provide advice from peer-reviewers and editors about how to solve each problem in manuscripts prior to their peer-review. The Preferred Reporting Items for study Designs in Endodontology (PRIDE) website (http://pride-endodonticguidelines.org/prile/) provides a link to the PRILE 2021 explanation and elaboration document as well as to the checklist and flowchart.
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Affiliation(s)
- Venkateshbabu Nagendrababu
- Department of Preventive and Restorative Dentistry, College of Dental Medicine, University of Sharjah, Sharjah, UAE
| | | | - Ronald Ordinola-Zapata
- Division of Endodontics, University of Minnesota School of Dentistry, Minneapolis, MN, USA
| | - Ove A Peters
- School of Dentistry, University of Queensland, Herston, Australia.,Department of Endodontics, Arthur A Dugoni School of Dentistry, University of Pacific, San Francisco, USA
| | - Isabela N Rôças
- Department of Endodontics, Faculty of Dentistry, Grande Rio University, Rio de Janeiro, Brazil.,Department of Endodontics and Dental Research, Iguaçu University, Nova Iguaçu, Rio de Janeiro, Brazil
| | - José F Siqueira
- Department of Endodontics, Faculty of Dentistry, Grande Rio University, Rio de Janeiro, Brazil.,Department of Endodontics and Dental Research, Iguaçu University, Nova Iguaçu, Rio de Janeiro, Brazil
| | - Ekta Priya
- Division of Children and Community Oral Health, School of Dentistry, International Medical University, Kuala Lumpur, Malaysia
| | - Jayakumar Jayaraman
- Department of Developmental Dentistry, University of Texas Health School of Dentistry, San Antonio, TX, USA
| | - Shaju J Pulikkotil
- Division of Clinical Dentistry, School of Dentistry, International Medical University, Kuala Lumpur, Malaysia
| | - Nandini Suresh
- Faculty of Dentistry, Meenakshi Academy of Higher Education and Research, Meenakshi Ammal Dental College, Chennai, India
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Weissheimer T, Heck L, Calefi PHS, Alcalde MP, Rosa RA, Vivan RR, Duarte MAH, Só MVR. Evaluation of the mechanical properties of different nickel–titanium retreatment instruments. AUST ENDOD J 2020; 47:265-272. [DOI: 10.1111/aej.12474] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 10/27/2020] [Accepted: 11/21/2020] [Indexed: 11/27/2022]
Affiliation(s)
- Theodoro Weissheimer
- Department of Conservative Dentistry Federal University of Rio Grande do Sul Porto Alegre Brazil
| | - Luana Heck
- Department of Conservative Dentistry Federal University of Rio Grande do Sul Porto Alegre Brazil
| | - Pedro Henrique Souza Calefi
- Department of Operative Dentistry Endodontics and Dental Materials Bauru School of Dentistry University of São Paulo São Paulo Brazil
| | | | - Ricardo Abreu Rosa
- Department of Conservative Dentistry Federal University of Rio Grande do Sul Porto Alegre Brazil
| | - Rodrigo Ricci Vivan
- Department of Operative Dentistry Endodontics and Dental Materials Bauru School of Dentistry University of São Paulo São Paulo Brazil
| | - Marco Antonio Hungaro Duarte
- Department of Operative Dentistry Endodontics and Dental Materials Bauru School of Dentistry University of São Paulo São Paulo Brazil
| | - Marcus Vinícius Reis Só
- Department of Conservative Dentistry Federal University of Rio Grande do Sul Porto Alegre Brazil
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Htun PH, Ebihara A, Maki K, Kimura S, Nishijo M, Kyaw MS, Okiji T. Comparison of Torque, Screw-in Force, and Shaping Ability of Glide Path Instruments in Continuous Rotation and Optimum Glide Path Motion. J Endod 2020; 47:94-99. [PMID: 33002538 DOI: 10.1016/j.joen.2020.09.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 10/23/2022]
Abstract
INTRODUCTION This study aimed to analyze torque/force generation and transportation in double-curved canals instrumented with 3 types of glide path files using optimum glide path (OGP) motion in comparison with continuous rotation. METHODS Sixty simulated double-curved canals were prepared with #10/0.05 or #15/0.03 HyFlex EDM Glidepath files (Coltene/Whaledent, Altstätten, Switzerland) or a #13/0.04 prototype MANI Glidepath file (Tochigi, Japan) using OGP motion or continuous rotation (n = 10 each). Canals were sequentially prepared to 20 mm and 22 mm (full working length) using automated root canal instrumentation and a torque/force analyzing device. Transportation was calculated at 1-9 mm from the apex. Data were compared using 2-way analysis of variance followed by a post hoc simple main effect test with Bonferroni correction and a Kruskal-Wallis test (α = 5%). RESULTS All #10/0.05 instruments fractured. In the 22-mm preparation, the OGP motion resulted in lower clockwise torque and screw-in force than did continuous rotation (P < .05). In the 20-mm preparation, #15/0.03 instruments recorded a lower screw-in force for OGP motion than for continuous rotation (P < .05). Comparing the 2 preparation phases, OGP motion generated no significant differences; however, continuous rotation developed higher clockwise torque and screw-in force in the 22-mm preparation than in the 20-mm preparation (P < .05). There was no significant difference among the tested groups for transportation values. CONCLUSIONS Compared with continuous rotation, OGP motion generated less screw-in force, lower clockwise torque, and similar transportation. The #15/0.03 HyFlex EDM instrument and the #13/0.04 prototype MANI instrument performed similarly well.
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Affiliation(s)
- 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), Tokyo, Japan
| | - Arata Ebihara
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
| | - Keiichiro Maki
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Shunsuke Kimura
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Miki Nishijo
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Moe Sandar Kyaw
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Takashi Okiji
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
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Martins JN, Nogueira Leal Silva EJ, Marques D, Ginjeira A, Braz Fernandes FM, De Deus G, Versiani MA. Influence of Kinematics on the Cyclic Fatigue Resistance of Replicalike and Original Brand Rotary Instruments. J Endod 2020; 46:1136-1143. [DOI: 10.1016/j.joen.2020.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/16/2020] [Accepted: 05/01/2020] [Indexed: 10/24/2022]
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Lee JY, Kwak SW, Ha JH, Kim HC. Ex-Vivo Comparison of Torsional Stress on Nickel-Titanium Instruments Activated by Continuous Rotation or Adaptive Motion. MATERIALS 2020; 13:ma13081900. [PMID: 32316559 PMCID: PMC7215760 DOI: 10.3390/ma13081900] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/09/2020] [Accepted: 04/13/2020] [Indexed: 11/30/2022]
Abstract
This study aimed to evaluate the effect of adaptive motion applied to conventional nickel-titanium (NiTi) rotary instruments on torsional stress generation during shaping procedure. One hundred and twenty mesio-buccal canals of molars were randomly assigned to two groups according to the kinetics; adaptive motion (AD) and continuous rotation (CR). Each group was divided into four subgroups (n = 15) according to the NiTi instrument systems: HyFlex EDM, One Curve, Twisted File Adaptive, and ProTaper Next. A glide path was established with PathFile #1, for each file group being used with either of the kinetic movements. During the instrumentation with the designated motion and file system, the generated torque was measured via the control unit and acquisition module. Based on the acquired data, the maximum and total torque were calculated. The data were statistically analyzed using Kruskal–Wallis and Mann–Whitney tests at a significance level of 95%. The maximum and total torque generated by all instruments were significantly reduced by the adaptive motion (p < 0.05). In the CR group, HyFlex EDM generated the highest maximum and total stress. In the AD group, HyFlex EDM showed the highest maximum torsional stress, and One Curve showed the highest total torsional stress (p < 0.05). The TF Adaptive instrument with adaptive movement produced the lowest maximum and total torsional stress (p < 0.05). Under the conditions of this study, the use of adaptive motion would be useful to reduce the torsional stress of instrument and root dentin. The reduction of torsional stress through adaptive motion may enhance the durability of instruments and reduce the potential risk of dentinal cracks.
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Affiliation(s)
- Joo Yeong Lee
- Department of Conservative Dentistry, Dental Research Institute, School of Dentistry, Pusan National University, Yangsan 50612, Korea; (J.Y.L.); (S.W.K.)
| | - Sang Won Kwak
- Department of Conservative Dentistry, Dental Research Institute, School of Dentistry, Pusan National University, Yangsan 50612, Korea; (J.Y.L.); (S.W.K.)
| | - Jung-Hong Ha
- Department of Conservative Dentistry, School of Dentistry, Kyungpook National University, Daegu 41940, Korea;
| | - Hyeon-Cheol Kim
- Department of Conservative Dentistry, Dental Research Institute, School of Dentistry, Pusan National University, Yangsan 50612, Korea; (J.Y.L.); (S.W.K.)
- Correspondence: ; Tel.: +82-55-360-5222
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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: 49] [Impact Index Per Article: 9.8] [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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Performance of Reciproc Blue R25 Instruments in Shaping the Canal Space without Glide Path. J Endod 2019; 45:194-198. [PMID: 30711177 DOI: 10.1016/j.joen.2018.10.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 10/16/2018] [Accepted: 10/23/2018] [Indexed: 10/27/2022]
Abstract
INTRODUCTION This study assessed the frequency in which Reciproc Blue R25 instruments (VDW, Munich, Germany) reached the full working length (WL) of mandibular molar canals without a glide path. The influence of the type of electric motor (ie, conventional corded or cordless) on the instrument's performance was also assessed. METHODS One hundred mandibular molars with slight to moderate root canals were selected and randomly assigned into 1 of 2 experimental groups according to the type of electric motor used: conventional corded (VDW Silver, VDW) or cordless motors (VDW.CONNECT Drive, VDW). Therefore, 50 molars and 154 root canals were selected for each motor. Reciproc Blue R25 instruments were used until reaching two thirds of the estimated WL. Then, a size 10 K-file was passively inserted to determine the full WL. No active instrumentation movement was performed with a size 10 K-file. Independently, whether a size 10 K-file reached the apex or not, Reciproc Blue R25 instruments were used to complete canal preparation. When the Reciproc Blue R25 instrument was able to reach the full WL, the case was classified as "reaching the full working length" (RFWL). If the instrument was not able to reach the full WL, the case was classified as "not reaching the full working length" (NRFWL). The chi-square test of goodness of fit was used to verify whether the observed frequencies of RFWL and NRFWL adhered to the expected ones. A 5% cutoff level of significance was considered for statistical assumptions. RESULTS Reciproc Blue R25 instruments were able to reach the full WL in 304 root canals (98.70%). The chi-square test revealed the observed frequencies of RFWL and NRFWL to be significantly different from the expected frequencies (χ2 = 292,208, P = .000). The frequency of RFWL and NRFWL was exactly the same for both types of electric motors. No instrument fractured, and a single file deformed. In 50 of 308 root canals, a size 10 K-file was unable to passively reach the full WL. From these 50 canals, Reciproc Blue R25 instruments were able to reach the full WL in 47 of them. CONCLUSIONS Reciproc Blue R25 instruments were able to reach the full WL in a high frequency of cases. The type of electric motor used did not interfere in the frequency of RFWL cases. No instrument fractured, and a single file deformed.
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Effect of Different Speeds of Up-and-down Motion on Canal Centering Ability and Vertical Force and Torque Generation of Nickel-titanium Rotary Instruments. J Endod 2019; 45:68-72.e1. [DOI: 10.1016/j.joen.2018.10.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 10/02/2018] [Accepted: 10/04/2018] [Indexed: 11/19/2022]
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NISHIJO M, EBIHARA A, TOKITA D, DOI H, HANAWA T, OKIJI T. Evaluation of selected mechanical properties of NiTi rotary glide path files manufactured from controlled memory wires. Dent Mater J 2018; 37:549-554. [DOI: 10.4012/dmj.2017-276] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Miki NISHIJO
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU)
| | - Arata EBIHARA
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU)
| | - Daisuke TOKITA
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU)
| | - Hisashi DOI
- Department of Metallic Biomaterials, Division of Biomedical Materials, Institute of Bioengineering, Tokyo Medical and Dental University (TMDU)
| | - Takao HANAWA
- Department of Metallic Biomaterials, Division of Biomedical Materials, Institute of Bioengineering, 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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Impact of Case Difficulty on Endodontic Mishaps in an Undergraduate Student Clinic. J Endod 2018; 44:1088-1095. [DOI: 10.1016/j.joen.2018.03.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 03/19/2018] [Accepted: 03/19/2018] [Indexed: 11/23/2022]
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Cyclic fatigue resistance of R-Pilot, WaveOne Gold Glider, and ProGlider glide path instruments. Clin Oral Investig 2018; 22:3007-3012. [DOI: 10.1007/s00784-018-2391-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 02/09/2018] [Indexed: 11/26/2022]
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