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Martins JNR, Pinto R, Silva EJNL, Simões-Carvalho M, Marques D, Martins RF, Versiani MA. 3D Surface Scanning-A Novel Protocol to Characterize Virtual Nickel-Titanium Endodontic Instruments. MATERIALS (BASEL, SWITZERLAND) 2023; 16:3636. [PMID: 37241263 PMCID: PMC10222178 DOI: 10.3390/ma16103636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 04/27/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023]
Abstract
The nickel-titanium (NiTi) instruments' geometry plays an important role in their performance and behavior. The present assessment intends to validate and test the applicability of a 3D surface scanning method using a high-resolution laboratory-based optical scanner to create reliable virtual models of NiTi instruments. Sixteen instruments were scanned using a 12-megapixel optical 3D scanner, and methodological validation was performed by comparing quantitative and qualitative measurements of specific dimensions and identifying some geometric features of the 3D models with images obtained through scanning electron microscopy. Additionally, the reproducibility of the method was assessed by calculating 2D and 3D parameters of three different instruments twice. The quality of the 3D models created by two different optical scanners and a micro-CT device was compared. The 3D surface scanning method using the high-resolution laboratory-based optical scanner allowed for the creation of reliable and precise virtual models of different NiTi instruments with discrepancies varying from 0.0002 to 0.0182 mm. The reproducibility of measurements performed with this method was high, and the acquired virtual models were adequate for use in in silico experiments, as well as for commercial or educational purposes. The quality of the 3D model obtained using the high-resolution optical scanner was superior to that acquired by micro-CT technology. The ability to superimpose virtual models of scanned instruments and apply them in Finite Element Analysis and educational purposes was also demonstrated.
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Affiliation(s)
- Jorge N. R. Martins
- Faculdade de Medicina Dentária, Universidade de Lisboa, 1600-277 Lisboa, Portugal
- 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
| | - Ricardo Pinto
- Faculdade de Medicina Dentária, Universidade de Lisboa, 1600-277 Lisboa, Portugal
| | - Emmanuel J. N. L. Silva
- Department of Endodontics, School of Dentistry, Grande Rio University (UNIGRANRIO), Rio de Janeiro 21210-623, Brazil
- Department of Endodontics, Fluminense Federal University, Niterio, Rio de Janeiro 24220-900, Brazil
| | - Marco Simões-Carvalho
- 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
- 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
| | - Rui F. Martins
- UNIDEMI, Department of Mechanical and Industrial Engineering, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
| | - Marco A. Versiani
- Dental Specialty Center, Brazilian Military Police, Belo Horizonte, Minas Gerais 30350-190, Brazil
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Abstract
A very extensive literature review presents the possibilities and needs of using, in endodontics, the alloys commonly known as nitinol. Nitinol, as the most modern group of engineering materials used to develop root canals, is equilibrium nickel and titanium alloys in terms of the elements’ atomic concentration, or very similar. The main audience of this paper is engineers, tool designers and manufacturers, PhD students, and students of materials and manufacturing engineering but this article can also certainly be used by dentists. The paper aims to present a full material science characterization of the structure and properties of nitinol alloys and to discuss all structural phenomena that determine the performance properties of these alloys, including those applied to manufacture the endodontic tools. The paper presents the selection of these alloys’ chemical composition and processing conditions and their importance in the endodontic treatment of teeth. The results of laboratory studies on the analysis of changes during the sterilization of endodontic instruments made of nitinol alloys are also included. The summary of all the literature analyses is an SWOT analysis of strengths, weaknesses, opportunities, and threats, and is a forecast of the development strategy of this material in a specific application such as endodontics.
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Chien PYH, Walsh LJ, Peters OA. Finite element analysis of rotary nickel-titanium endodontic instruments: A critical review of the methodology. Eur J Oral Sci 2021; 129:e12802. [PMID: 34105190 DOI: 10.1111/eos.12802] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 11/30/2022]
Abstract
Finite element analysis has been a valuable research tool for rotary nickel-titanium endodontic files over the last two decades. This review aims to summarise and critique the methodology as used in currently available endodontic literature for finite element analysis of rotary nickel-titanium instruments. An electronic literature research in PubMed and Scopus databases was performed using the appropriate search terms, and the titles and abstracts were screened for relevance. The review revealed an inconsistent approach to the finite element method, particularly with regards to the boundary conditions in which the instruments are tested. Moreover, there is a lack of experimental data to validate in silico findings. A standardised protocol to finite element analysis of rotary endodontic instruments could be considered for future studies.
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Affiliation(s)
- Philip Y-H Chien
- School of Dentistry, The University of Queensland, Brisbane, QLD, Australia
| | - Laurence J Walsh
- School of Dentistry, The University of Queensland, Brisbane, QLD, Australia
| | - Ove A Peters
- School of Dentistry, The University of Queensland, Brisbane, QLD, Australia
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Pereira RD, Leoni GB, Silva-Sousa YT, Gomes EA, Dias TR, Brito-Júnior M, Sousa-Neto MD. Impact of Conservative Endodontic Cavities on Root Canal Preparation and Biomechanical Behavior of Upper Premolars Restored with Different Materials. J Endod 2021; 47:989-999. [PMID: 33774045 DOI: 10.1016/j.joen.2021.03.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 03/12/2021] [Accepted: 03/16/2021] [Indexed: 11/24/2022]
Abstract
INTRODUCTION The purpose of this study was to evaluate the impact of conservative endodontic cavities (CECs) on root canal preparation, restoration, and biomechanical behavior of teeth prepared using different shaping systems and restorative materials. METHODS Ninety upper premolars with a bifurcated root were matched based on morphology and randomly assigned to a control group (n = 10) or 1 of the following experimental groups (n = 40): traditional endodontic cavity and CEC. Teeth were subdivided according to instrumentation (n = 10) as follows: ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland), Reciproc (VDW GmbH, Munich, Germany), Reciproc Blue (VDW GmbH), and Hyflex EDM (Coltene/Whaledent, Altstätten, Switzerland). After canal obturation, teeth were restored using temporary material, conventional composite, regular bulk fill composite, or bulk fill flow combined with conventional composite. Before and after preparation and after obturation, the teeth were scanned using micro-computed tomographic imaging. Canal transportation (CT), the percentage of untouched canal surfaces (UCSs), voids in restoration (VRs), and residual filling material in the pulp chamber were evaluated. Finite element analysis, fracture resistance, and the failure pattern were recorded. The data were analyzed using analysis of variance and the Tukey and chi-square tests. RESULTS CECs had greater CT, percentage of filling material, and VRs compared with traditional endodontic cavities (P < .0001). The highest CT and UCSs were observed in CEC with ProTaper Universal. Bulk fill flow combined with conventional composite showed a lower percentage of VRs compared with other restorative materials (P < .05). Finite element analysis, fracture resistance, and failure pattern revealed similar behaviors in all groups (P > .05) . CONCLUSIONS CECs had a negative impact on root canal centralization, UCSs, cleaning of the pulp chamber, and percentage of VRs. Controlled memory instruments were the most adequate for the root canal preparation of CECs. The endodontic cavity did not influence the biomechanical behavior of restored teeth.
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Affiliation(s)
- Rodrigo Dantas Pereira
- Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | | | | | - Erica Alves Gomes
- School of Dentistry, University of Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
| | - Tatiane Rocco Dias
- School of Dentistry, University of Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
| | - Manoel Brito-Júnior
- Department of Dentistry, State University of Montes Claros, Montes Claros, Minas Gerais, Brazil
| | - Manoel Damião Sousa-Neto
- Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
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Fu HY, Wang FF, Hou XM. [Construction and mechanical analysis of finite element model for bending property of controlled memory wire nickel-titanium rotary file]. JOURNAL OF PEKING UNIVERSITY. HEALTH SCIENCES 2019; 51:131-135. [PMID: 30773557 DOI: 10.19723/j.issn.1671-167x.2019.01.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To construct a model for a controlled memory (CM) nickel-titanium (NiTi) file and another M-wire NiTi file with the same geometry by using finite element analysis. To evaluate the flexibility of a CM NiTi file by using three dimensional finite element method and to compare its mechanical responses with that M-wire NiTi. METHODS Based on the reverse engineering, the 21 mm long, 25#/08 taper Hyflex NT NiTi file and Hyflex CM NiTi file were fixed by the cantilever bending model at a distance of 9.5 mm from the tip of the file. The mechanical tester's indenter was loaded/unloaded at a distance of 3 mm from the tip of the file. The maximum displacement was 3 mm, the load displacement curve was obtained. Subsequently, by using a micro-CT to scan (layer spacing of 8 μm) NiTi files, and ABAQUS (6.10) was introduced to construct a geometric model. Hyflex NT was considered as a shapememory alloy constitutive model, Hyflex CM was considered as a power-hardening plastic constitutive model, respectively. Comparing the load-displacement curve of cantilever bending in the three-dimensional finite element model with the load-displacement curve in the experiment. RESULTS Two tetrahedral element models were constructed, the total number of nodes was 99 353 and the total number of cells was 63 744. When the loading displacement was 1 mm, the stress distribution of the cross section at 6.1 mm from the tip of the file was observed. The upper and lower surfaces were subjected to the maximum bending stress and entered the phase transformation yield stage. The finite element simulation could clearly show the deformation of the file. Various information such as deformation characteristics and stress distribution in the process were well fitted to the actual experimental curve. CONCLUSION The constitutive behavior of the material has a significant effect on the mechanical behavior of NiTi file. The finite element model established for the NiTi file of the CM wire can accurately capture the characteristics of various deformation processes of the NiTi root canal file, and it has a good fit with the actual experimental curve. The finite element model can be used for study on bending properties of CM wire.
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Affiliation(s)
- H Y Fu
- Department of Stomatology, Peking University First Hospital, Beijing 100034, China
| | - F F Wang
- Department of Stomatology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - X M Hou
- Second Clinical Division, Peking University School and Hospital of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing 100101, China
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Prados-Privado M, Rojo R, Ivorra C, Prados-Frutos JC. Finite element analysis comparing WaveOne, WaveOne Gold, Reciproc and Reciproc Blue responses with bending and torsion tests. J Mech Behav Biomed Mater 2019; 90:165-172. [DOI: 10.1016/j.jmbbm.2018.10.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/04/2018] [Accepted: 10/05/2018] [Indexed: 10/28/2022]
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Ataya M, Ha JH, Kwak SW, Abu-Tahun IH, El Abed R, Kim HC. Mechanical Properties of Orifice Preflaring Nickel-titanium Rotary Instrument Heat Treated Using T-Wire Technology. J Endod 2018; 44:1867-1871. [PMID: 30390971 DOI: 10.1016/j.joen.2018.08.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 08/28/2018] [Accepted: 08/30/2018] [Indexed: 10/28/2022]
Abstract
INTRODUCTION This study examined whether the use of T-Wire heat treatment enhanced the resistance to torsional force, cyclic fatigue, and bending stiffness of orifice preflaring nickel-titanium instruments. METHODS Ninety heat-treated OneFlare (OFT; Micro-Mega, Besançon, France) and conventional OneFlare (OFC, Micro-Mega) nickel-titanium files of size #25/.09 with identical geometries were selected (n = 15 per group for each test). Torsional resistance was evaluated through the measurement of ultimate torsional strength, distortion angle, and toughness during rotational loading. Cyclic fatigue resistance was evaluated through measurement of the number of cycles to failure for each instrument. Stiffness was evaluated by observation of the bending moment on attaining a 45° bend. Independent t tests were performed for statistical analysis. After torsional and cyclic fatigue tests, all fractured fragments were examined under a field emission scanning electron microscope to observe characteristics of the fractured surfaces. RESULTS OFT showed better cyclic fatigue resistance and lower bending stiffness than OFC (P < .05); however, OFT and OFC did not differ significantly in terms of torsional resistance. The fractured cross-sectional surfaces had characteristics typical of cyclic fatigue and torsional fractures. CONCLUSIONS The OFT instruments made using T-Wire heat treatment had better cyclic fatigue resistance and lower bending stiffness with no decline in torsional strength.
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Affiliation(s)
- Maamoun Ataya
- Endodontic Department, Hamdan Bin Mohammed College of Dental Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
| | - Jung-Hong Ha
- Department of Conservative Dentistry, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Sang Won Kwak
- Department of Conservative Dentistry, School of Dentistry, Dental Research Institute, Pusan National University, Yangsan, Korea
| | - Ibrahim H Abu-Tahun
- Department of Conservative Dentistry, School of Dentistry, The University of Jordan, Amman, Jordan
| | - Rashid El Abed
- Endodontic Department, Hamdan Bin Mohammed College of Dental Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
| | - Hyeon-Cheol Kim
- Department of Conservative Dentistry, School of Dentistry, Dental Research Institute, Pusan National University, Yangsan, Korea.
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Zupanc J, Vahdat-Pajouh N, Schäfer E. New thermomechanically treated NiTi alloys - a review. Int Endod J 2018; 51:1088-1103. [DOI: 10.1111/iej.12924] [Citation(s) in RCA: 166] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 03/16/2018] [Indexed: 11/29/2022]
Affiliation(s)
- J. Zupanc
- Department of Periodontology and Operative Dentistry; Westphalian Wilhelms-University; Münster Germany
| | - N. Vahdat-Pajouh
- Department of Periodontology and Operative Dentistry; Westphalian Wilhelms-University; Münster Germany
| | - E. Schäfer
- Central Interdisciplinary Ambulance in the School of Dentistry; Münster Germany
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Ha JH, Kwak SW, Versluis A, Lee CJ, Park SH, Kim HC. The geometric effect of an off-centered cross-section on nickel-titanium rotary instruments: A finite element analysis study. J Dent Sci 2017; 12:173-178. [PMID: 30895044 PMCID: PMC6395356 DOI: 10.1016/j.jds.2016.11.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/17/2016] [Indexed: 11/24/2022] Open
Abstract
Background/purpose Geometric design dictates the mechanical performance of nickel–titanium rotary instruments. Using finite element (FE) analysis, this study evaluated the effects of an off-centered cross-sectional design on the stiffness and stress distribution of nickel–titanium rotary instruments. Materials and methods We constructed three-dimensional FE models, using ProTaper-NEXT type design (PTN) as well as three other virtual instruments with varied cross-sectional aspect ratios but all with the same cross-sectional area. The cross-sectional aspect ratio of the PTN was 0.75, while others were assigned to have ratios of 1.0 (square), 1.5 (rectangle), and 2.215 (centered-rectangle). The PTN center of the cross-section was ‘k’, while others were designed to have 0.9992k, 0.7k, and 0 for the square, rectangle, and centered-rectangle models, respectively. To compare the stiffness of the four FE models, we numerically analyzed their mechanical response under bending and torque. Results Under the bending condition, the square model was found to be the stiffest, followed by the PTN, rectangle, and then the centered-rectangle model. Under the torsion, the square model had the smallest distortion angle, while the rectangular model had the highest distortion angle. Conclusion Under the limitation of this study, the PTN type off-centered cross-sectional design appeared the most optimal configuration among the tested designs for high bending stiffness with cutting efficiency while rotational stiffness remained similar with the other designs.
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Affiliation(s)
- Jung-Hong Ha
- Department of Conservative Dentistry, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - Sang Won Kwak
- Department of Conservative Dentistry, School of Dentistry, Dental Research Institute, Pusan National University, Yangsan, South Korea
| | - Antheunis Versluis
- Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Chan-Joo Lee
- Dongnam Regional Division, Korea Institute of Industrial Technology, Jinju, South Korea
| | - Se-Hee Park
- Department of Conservative Dentistry, College of Dentistry, Gangneung-Wonju National University, Gangneung, South Korea
| | - Hyeon-Cheol Kim
- Department of Conservative Dentistry, School of Dentistry, Dental Research Institute, Pusan National University, Yangsan, South Korea
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El-Anwar MI, Yousief SA, Kataia EM, El-Wahab TMA. Finite Element Study on Continuous Rotating versus Reciprocating Nickel-Titanium Instruments. Braz Dent J 2016; 27:436-41. [DOI: 10.1590/0103-6440201600480] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 05/17/2016] [Indexed: 09/02/2023] Open
Abstract
Abstract In the present study, GTX and ProTaper as continuous rotating endodontic files were numerically compared with WaveOne reciprocating file using finite element analysis, aiming at having a low cost, accurate/trustworthy comparison as well as finding out the effect of instrument design and manufacturing material on its lifespan. Two 3D finite element models were especially prepared for this comparison. Commercial engineering CAD/CAM package was used to model full detailed flute geometries of the instruments. Multi-linear materials were defined in analysis by using real strain-stress data of NiTi and M-Wire. Non-linear static analysis was performed to simulate the instrument inside root canal at a 45° angle in the apical portion and subjected to 0.3 N.cm torsion. The three simulations in this study showed that M-Wire is slightly more resistant to failure than conventional NiTi. On the other hand, both materials are fairly similar in case of severe locking conditions. For the same instrument geometry, M-Wire instruments may have longer lifespan than the conventional NiTi ones. In case of severe locking conditions both materials will fail similarly. Larger cross sectional area (function of instrument taper) resisted better to failure than the smaller ones, while the cross sectional shape and its cutting angles could affect instrument cutting efficiency.
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Elemam RF, Capelas JA, Vaz MAP, Viriato N, Pereira ML, Azevedo A, West J. Evaluating Transportation by Comparing Several uses of Rotary Endodontic Files. J Contemp Dent Pract 2015; 16:927-32. [PMID: 27018025 DOI: 10.5005/jp-journals-10024-1783] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
AIM To evaluate the frequent use of ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland) systems on shaping ability of root canal utilizing Solidworks (2014, Dassault Systemes) software. MATERIALS AND METHODS Thirty-six root canals in clear resin blocks (Dentsply-Maillefer) were allocated into six experimental groups (n = 36). Six new sets of PTN instruments (Dentsply Maillefer, Ballaigues, Switzerland) were used six times to shape the resin blocks. A #15 K-file was inserted to the working length (WL), followed by ProGlider (PG) to create a glide path. Sequential use of PTN instrumentation in a crown-down technique was used to reach size (30/07) apically. Macroscopic photos of the blocks were taken before and after instrumentation, layered by Paint Shop Pro 9 from JascSoftware, and then canal transportation was measured using Solidwork 2014. The data were analyzed by SPSS software version 22. Multivariate statistical analysis general linear model (GLM) was also applied. Bonferroni correction test was used in multiple comparisons and the statistical significance was set to 0.05. RESULTS There was no difference in canal transportation resulted from utilizing PTN files after six multiple uses; in addition, the PTN files showed ability to maintain the original canal anatomy, especially in the apical level, where lowest total mean value of canal center displacement was seen (3 mm level) (0.019 ± 0.017). CONCLUSION ProTaper Next files can be used to prepare single and multiple canals in a single furcated tooth. CLINICAL SIGNIFICANCE ProTaper Next nickel-titanium (NiTi) file system is a safe instrument that respects the canal shape, allows practitioners to treat difficult cases with good results, and low risk of separation.
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Affiliation(s)
- Ranya F Elemam
- PhD, Department of Endodontics, Faculty of Dental Medicine University of Porto, Rua Dr. Manuel Pereira da Silva 4200-393, Porto, Portugal Phone: +351 92005818, e-mail:
| | - J A Capelas
- Department of Endodontics, Faculty of Dental Medicine University of Porto, Porto, Portugal
| | - Mário A P Vaz
- Department of Mechanical Engineering, Faculty of Engineering University of Porto, Porto, Portugal
| | - Nuno Viriato
- Laboratory of Optics and Experimental Mechanics, INEGI-Institute of Mechanical Engineering and Industrial Management Porto, Portugal
| | - M L Pereira
- Faculty of Dental Medicine, University of Porto, EPI Unit-Institute of Public Health University of Porto, Porto, Portugal
| | - A Azevedo
- Faculty of Dental Medicine, University of Porto, EPI Unit-Institute of Public Health University of Porto, Porto, Portugal
| | - John West
- Department of Endodontics, University of Washington School of Dentistry, Washington, USA
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Tang WR, Smales RJ, Chen HF, Guo XY, Si HY, Gao LM, Zhou WB, Wu YN. Prevention and management of fractured instruments in endodontic treatment. World J Surg Proced 2015; 5:82-98. [DOI: 10.5412/wjsp.v5.i1.82] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/12/2014] [Accepted: 01/12/2015] [Indexed: 02/06/2023] Open
Abstract
Intracanal instrument fracture is an unpredictable and problematic occurrence that can prevent adequate cleaning and shaping procedures and influence the prognosis of endodontic treatment. The prevalence of instrument fracture is reported to range between 0.28% and 16.2%. This article presents an overview of the prevention and management of instruments fractured during endodontic therapy on the basis of literature retrieved from PubMed and selected journal searches. Instrument fracture occurs because of reduced metal fatigue and/or torsional resistance. The reasons include canal morphology and curvature, manufacturing processes and instrument design, instrument use times and technique, rotational speeds and operator experience. With the development of various equipment and techniques, most of the retained instrument separations can be removed safely. However, in canals without associated periapical disease not every fractured separation should be removed from difficult locations because of the increased risk for root perforation and fracture. In difficult cases, either retain or bypass the fragment in the root canal and ensure regular follow-up reviews. Fractured instruments retained in the presence of periapical disease reduce significantly the prognosis of endodontically treated teeth, indicating a greater need to attempt the removal or bypass of the file separations. Apical surgery might be required in some instances, emphasizing the importance of preventing instrument fracture.
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Arias A, de la Macorra JC, Azabal M, Hidalgo JJ, Peters OA. Prospective case controlled clinical study of post-endodontic pain after rotary root canal preparation performed by a single operator. J Dent 2015; 43:389-95. [DOI: 10.1016/j.jdent.2014.07.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 07/09/2014] [Accepted: 07/10/2014] [Indexed: 10/25/2022] Open
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Bonessio N, Pereira ESJ, Lomiento G, Arias A, Bahia MGA, Buono VTL, Peters OA. Validated finite element analyses of WaveOne Endodontic Instruments: a comparison between M-Wire and NiTi alloys. Int Endod J 2014; 48:441-50. [PMID: 24923193 DOI: 10.1111/iej.12333] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 06/06/2014] [Indexed: 01/30/2023]
Abstract
AIM To validate torsional analysis, based on finite elements, of WaveOne instruments against in vitro tests and to model the effects of different nickel-titanium (NiTi) materials. METHODOLOGY WaveOne reciprocating instruments (Small, Primary and Large, n = 8 each, M-Wire) were tested under torsion according to standard ISO 3630-1. Torsional profiles including torque and angle at fracture were determined. Test conditions were reproduced through Finite Element Analysis (FEA) simulations based on micro-CT scans at 10-μm resolution; results were compared to experimental data using analysis of variance and two-sided one sample t-tests. The same simulation was performed on virtual instruments with identical geometry and load condition, based on M-Wire or conventional NiTi alloy. RESULTS Torsional profiles from FEA simulations were in significant agreement with the in vitro results. Therefore, the models developed in this study were accurate and able to provide reliable simulation of the torsional performance. Stock NiTi files under torsional tests had up to 44.9%, 44.9% and 44.1% less flexibility than virtual M-Wire files at small deflections for Small, Primary and Large instruments, respectively. As deflection levels increased, the differences in flexibility between the two sets of simulated instruments decreased until fracture. Stock NiTi instruments had a torsional fracture resistance up to 10.3%, 8.0% and 7.4% lower than the M-Wire instruments, for the Small, Primary and Large file, respectively. CONCLUSION M-Wire instruments benefitted primarily through higher material flexibility while still at low deflection levels, compared with conventional NiTi alloy. At fracture, the instruments did not take complete advantage of the enhanced fractural resistance of the M-Wire material, which determines only limited improvements of the torsional performance.
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Affiliation(s)
- N Bonessio
- Department of Structural Engineering, University of California, San Diego, CA, USA
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A study on the influence of Ni–Ti M-Wire in the flexural fatigue life of endodontic rotary files by using Finite Element Analysis. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 40:172-9. [DOI: 10.1016/j.msec.2014.03.061] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 02/03/2014] [Accepted: 03/07/2014] [Indexed: 11/20/2022]
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de Arruda Santos L, López JB, de Las Casas EB, de Azevedo Bahia MG, Buono VTL. Mechanical behavior of three nickel-titanium rotary files: A comparison of numerical simulation with bending and torsion tests. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 37:258-63. [DOI: 10.1016/j.msec.2014.01.025] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 12/22/2013] [Accepted: 01/09/2014] [Indexed: 11/24/2022]
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Montalvão D, Alçada FS, Braz Fernandes FM, de Vilaverde-Correia S. Structural characterisation and mechanical FE analysis of conventional and M-Wire Ni-Ti alloys used in endodontic rotary instruments. ScientificWorldJournal 2014; 2014:976459. [PMID: 24574937 PMCID: PMC3918393 DOI: 10.1155/2014/976459] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 10/27/2013] [Indexed: 11/21/2022] Open
Abstract
The purpose of this study is to understand how the M-Wire alloy conditions the mechanical flexibility of endodontic rotary files at body temperature.Two different rotary instruments, a Profile GT 20/.06 and a Profile GT Series X 20/.06, were selected due to their geometrical similarity and their different constituent alloy. GT series X files are made from M-Wire, a Ni-Ti alloy allegedly having higher flexibility at body temperature. Both files were analysed by X-Ray Diffraction and Differential Scanning Calorimetry to investigate phase transformations and the effects of working temperature on these different alloys. Mechanical behaviour was assessed by means of static bending and torsional Finite Element simulations, taking into account the nonlinear superelastic behaviour of Ni-Ti materials. It was found that GT files present austenitic phase at body temperature, whereas GT series X present R-phase at temperatures under 40 °C with a potential for larger flexibility. For the same load conditions, simulations showed that the slight geometrical differences between the two files do not introduce great disagreement in the instruments' mechanical response. It was confirmed that M-Wire increases the instrument's flexibility, mainly due to the presence of R-phase at body temperature.
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Affiliation(s)
- Diogo Montalvão
- School of Engineering and Technology, University of Hertfordshire, College Lane, Hatfield, Hertfordshire AL10 9AB, UK
| | - Francisca Sena Alçada
- The Dental Implant and Gingival-Plastic Surgery Centre, 717 Christchurch Road, Bournemouth, Dorset BH7 6AF, UK
| | - Francisco Manuel Braz Fernandes
- CENIMAT/I3N, Materials Science Department, Faculty of Science and Technology, New University of Lisbon, Campus of Caparica, 2829-516 Caparica, Portugal
| | - Sancho de Vilaverde-Correia
- CENIMAT/I3N, Materials Science Department, Faculty of Science and Technology, New University of Lisbon, Campus of Caparica, 2829-516 Caparica, Portugal
- Department of Endodontics, School of Dental Medicine, University of Pennsylvania, 3451 Walnut Street, Philadelphia, PA 19104, USA
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Zhou H, Peng B, Zheng YF. An overview of the mechanical properties of nickel-titanium endodontic instruments. ACTA ACUST UNITED AC 2013. [DOI: 10.1111/etp.12045] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Comparison of the Mechanical Behavior between Controlled Memory and Superelastic Nickel-Titanium Files via Finite Element Analysis. J Endod 2013; 39:1444-7. [DOI: 10.1016/j.joen.2013.07.030] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 07/25/2013] [Accepted: 07/28/2013] [Indexed: 11/20/2022]
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Arias A, Perez-Higueras JJ, de la Macorra JC. Influence of clinical usage of GT and GTX files on cyclic fatigue resistance. Int Endod J 2013; 47:257-63. [PMID: 23808563 DOI: 10.1111/iej.12141] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 05/19/2013] [Indexed: 12/12/2022]
Abstract
AIM To compare static cyclic fatigue resistance of unused, unused and sterilized and clinically used conventional NiTi GT and M-Wire GTX files. METHODOLOGY One hundred and sixty new files (80 GT and 80 GT series X) were divided into four control groups and four experimental groups (n = 20 each). Control groups were new unused files and new sterilized files. In the experimental groups, instruments were used in three (GT1 and GTX1 groups) or four molars (GT2 and GTX2 groups). Cyclic fatigue resistance was tested in stainless steel curved canals (60°, r = 3 mm). Each file was rotated until fracture (300 rpm, 2 N cm torque). Time-to-fracture (s) was registered. Mean life, eta and beta parameters of their Weibull distributions were calculated. RESULTS Unused and sterilized GTX files will last significantly longer than GT files with a probability of 75% and 65%, respectively; whilst mean life was significantly longer for GT than for GTX in used files with a probability of 68%. Sterilized GT files will last longer than unused files with a probability of 66%. In both brands, unused and sterilized files will last significantly longer than files used clinically with a probability higher than 98%. The probability that GT will last longer after being used in three rather than four molars was 62% (statistically significant) and 52% (not statistically significant) for GTX. CONCLUSIONS GTX files had an extended cyclic fatigue life when compared with GT when they were unused or unused and sterilized, but GT were significantly more resistant to cyclic fatigue after clinical usage than GT series X files 3 mm from the tip. Sterilization of files enhanced the cyclic fatigue resistance of GT instruments. Clinical use of files diminished cyclic fatigue resistance.
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Affiliation(s)
- A Arias
- Department of Conservative Dentistry, School of Dentistry, Complutense University of Madrid, Madrid, Spain
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Ha JH, Kim SK, Cohenca N, Kim HC. Effect of R-phase Heat Treatment on Torsional Resistance and Cyclic Fatigue Fracture. J Endod 2013; 39:389-93. [DOI: 10.1016/j.joen.2012.11.028] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 11/07/2012] [Accepted: 11/12/2012] [Indexed: 11/24/2022]
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