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Zanza A, Russo P, Di Matteo P, Reda R, Di Nardo D, Gambarini G, Testarelli L. Mechanical properties and metallurgical features of two similar endodontic rotary instruments with different heat treatments (FireWire™ and Gold). Sci Prog 2022; 105:368504221103763. [PMID: 35656775 PMCID: PMC10364944 DOI: 10.1177/00368504221103763] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The aim of this study was to explain the mechanical differences between EdgeTaper Platinum (ETP) and ProTaper Gold (PTG) determining the transition temperatures and the composition of the alloy of ETP, since no data are present in literature. A total of 130 instruments were selected: 65 ETP F2 and 65 PTG F2. 20 instruments per type were submitted to each mechanical tests. The cyclic fatigue and torsional tests were performed at a pre-set temperature of 35 °C ± 1 °C. During the cyclic fatigue test, Time to fracture, number of cycles to fracture (NCF) and the fragment length (FL) were recorded. During the static torsional, Torque to Fracture (TtF) and FL were recorded. The fracture surface of 5 randomly selected fragments from each test was examined through a Scanning Electron Microscopy (SEM) and an EDX analysis was performed. 20 instruments per type were submitted to a bending test The force generated (grams) to bend each was recorded. Recorded data of mechanical and metallurgical tests were statistically analyzed using a one-way analysis of variance (ANOVA) test with significance set to a 95% confidence level. ETP F2 showed a higher cyclic fatigue resistance and bending ability than PTG F2, with a statistically significant difference (p < 0.05). PTG showed a higher torsional resistance with a statistically significant difference (p < 0.05). DSC analysis of 5 samples for each instrument type pointed out that the austenite finish temperature of PTG was higher than the ETP, respectively of 49.99 ± 3.31 (°C) and 38.92 ± 1.75 (°C). EDX analysis confirmed the near-equiatomic composition of the Ni-Ti alloys, with a presence of a third component recognized as rubidium in the ETP samples. ETP showed higher flexibility in comparison with PTG, despite the latter is characterized by a more martensitic characterization. since its Af temperature is higher than the ETP.
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Affiliation(s)
- Alessio Zanza
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, via Caserta 6, 00161 Rome, Italy
| | - Paola Russo
- Department of Chemical Engineering, Materials, Environment DICMA, La Sapienza University of Rome, via Scarpa, 00161 Rome, Italy
| | - Paola Di Matteo
- Department of Chemical Engineering, Materials, Environment DICMA, La Sapienza University of Rome, via Scarpa, 00161 Rome, Italy
| | - Rodolfo Reda
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, via Caserta 6, 00161 Rome, Italy
| | - Dario Di Nardo
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, via Caserta 6, 00161 Rome, Italy
| | - Gianluca Gambarini
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, via Caserta 6, 00161 Rome, Italy
| | - Luca Testarelli
- Department of Oral and Maxillo-Facial Sciences, Sapienza University of Rome, via Caserta 6, 00161 Rome, Italy
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Metallurgical Tests in Endodontics: A Narrative Review. Bioengineering (Basel) 2022; 9:bioengineering9010030. [PMID: 35049739 PMCID: PMC8773015 DOI: 10.3390/bioengineering9010030] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 11/17/2022] Open
Abstract
Since there are no reviews of the literature on this theme, the aim of this narrative review is to summarize the metallurgical tests used in endodontics, pointing out their functional use and their pros and cons and giving readers a user-friendly guide to serve as an orientation aid in the plethora of metallurgical tests. With this purpose, a literature search for articles published between January 2001 and December 2021 was conducted, using the electronic database PubMed to collect all published articles regarding the metallurgical tests used in endodontics for the evaluation of NiTi rotary instruments. The search was conducted using the following keywords: “metallurgy”, “differential scanning calorimetry” (DSC), “X-ray diffraction” (XRD), “atomic force microscopy” (AFM), “energy-dispersive X-ray spectroscopy” (EDS), “focused ion beam analysis” (FIB) and “Auger electron spectroscopy” (AES) combined with the term “endodontics” or “NiTi rotary instruments”. Considering the inclusion and exclusion criteria, of the 248 articles found, only 81 were included in the narrative review. According to the results, more than 50% of the selected articles were published in one of the two most relevant journals in endodontics: International Endodontic Journal (22.2%) and Journal of Endodontics (29.6%). The most popular metallurgical test was DSC, with 43 related articles, followed by EDS (33 articles), AFM (22 articles) and XRD (21 articles). Few studies were conducted using other tests such as FIB (2 articles), micro-Raman spectroscopy (4 articles), metallographic analysis (7 articles) and Auger electron spectroscopy (2 articles).
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Wu J, Liu SC, Li Z, Wang S, Xue DJ, Lin Y, Hu JS. Strain in perovskite solar cells: origins, impacts and regulation. Natl Sci Rev 2021; 8:nwab047. [PMID: 34691711 PMCID: PMC8363326 DOI: 10.1093/nsr/nwab047] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/28/2021] [Accepted: 03/12/2021] [Indexed: 11/23/2022] Open
Abstract
Metal halide perovskite solar cells (PSCs) have seen an extremely rapid rise in power conversion efficiencies in the past few years. However, the commercialization of this class of emerging materials still faces serious challenges, one of which is the instability against external stimuli such as moisture, heat and irradiation. Much focus has deservedly been placed on understanding the different origins of intrinsic instability and thereby enhancing their stability. Among these, tensile strain in perovskite films is an important source of instability that cannot be overcome using conventionally extrinsic stabilization approaches such as encapsulation. Here we review recent progress in the understanding of the origin of strain in perovskites as well as its corresponding characterization methods, and their impacts on the physical properties of perovskites and the performance of PSCs including efficiency and stability. We then summarize the latest advances in strain-regulation strategies that improve the intrinsic stability of perovskites and photovoltaic devices. Finally, we provide a perspective on how to make further progress in stable and high-efficiency PSCs via strain engineering.
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Affiliation(s)
- Jinpeng Wu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shun-Chang Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zongbao Li
- School of Material and Chemical Engineering, Tongren University, Tongren 554300, China
| | - Shuo Wang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Ding-Jiang Xue
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan Lin
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jin-Song Hu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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Alghamdi S, Huang X, Haapasalo M, Mobuchon C, Hieawy A, Hu J, Wang Z, Sobotkiewicz T, Shen Y. Effect of Curvature Location on Fatigue Resistance of Five Nickel-titanium Files Determined at Body Temperature. J Endod 2020; 46:1682-1688. [PMID: 32640265 DOI: 10.1016/j.joen.2020.06.041] [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: 03/04/2020] [Revised: 06/19/2020] [Accepted: 06/22/2020] [Indexed: 11/12/2022]
Abstract
INTRODUCTION The purpose of this study was to evaluate the effect of 5 different curvature locations on the fatigue resistance of thermomechanically treated nickel-titanium (NiTi) files and superelastic NiTi files at body temperature and to document the corresponding phase transformations. METHODS EndoSequence (ES; Brasseler USA, Savannah, GA), EndoSequence CM (ESCM, Brasseler USA), K3 (SybronEndo, Orange, CA), K3XF (SybronEndo), and Vortex Blue (VB; Dentsply Tulsa Dental Specialties, Tulsa, OK) NiTi files (size 25/.04) were subjected to fatigue tests inside customized artificial canals containing a curvature of 60° and a 3-mm radius. There were 5 different canals based on the location of initial curvature; these included groups in which the distance between the canal orifice and the location of the curvature (DOC) was 5, 6, 8, 10, and 11 mm. The model canal was immersed in water at 37°C ± 1°C. The number of cycles to failure (Nf) was recorded, and the fracture surface of the fragments was examined by scanning electron microscopy. Two unused files of each brand were examined by differential scanning calorimetry. RESULTS The Nf was highest in the 10-mm and 11-mm DOC groups and lowest with the 5-mm and 6-mm DOC groups (P < .05). ESCM files had the highest fatigue resistance followed by the VB, K3XF, K3, and ES files (P < .05). ESCM files had the highest Nf (P < .05), and ES and K3 files had the lowest Nf (P < .05) depending on the curvature location. Two endothermic peaks were observed on the heating curve of the heat-treated files (ESCM, K3XF, and VB). CONCLUSIONS The location of the canal curvature had a significant effect on the fatigue resistance of both heat-treated and superelastic NiTi files. The fatigue life of files in the coronal curve was quite short.
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Affiliation(s)
- Sarah Alghamdi
- Faculty of Dentistry, Department of Oral Biological and Medical Sciences, The University of British Columbia, Vancouver, Bitish Columbia, Canada
| | - Xiangya Huang
- Department of Conservative Dentistry and Endodontics, Guanghua School of Stomatology, Guangdong Province Key Laboratory of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Markus Haapasalo
- Faculty of Dentistry, Department of Oral Biological and Medical Sciences, The University of British Columbia, Vancouver, Bitish Columbia, Canada
| | - Christophe Mobuchon
- Department of Materials Engineering, The University of British Columbia, Vancouver, Bitish Columbia, Canada
| | - Ahmed Hieawy
- Faculty of Dentistry, Department of Oral Biological and Medical Sciences, The University of British Columbia, Vancouver, Bitish Columbia, Canada
| | - Jinghao Hu
- Faculty of Dentistry, Department of Oral Biological and Medical Sciences, The University of British Columbia, Vancouver, Bitish Columbia, Canada
| | - Zhejun Wang
- Faculty of Dentistry, Department of Oral Biological and Medical Sciences, The University of British Columbia, Vancouver, Bitish Columbia, Canada
| | - Tyler Sobotkiewicz
- Faculty of Dentistry, Department of Oral Biological and Medical Sciences, The University of British Columbia, Vancouver, Bitish Columbia, Canada
| | - Ya Shen
- Faculty of Dentistry, Department of Oral Biological and Medical Sciences, The University of British Columbia, Vancouver, Bitish Columbia, Canada.
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Shen Y, Tra C, Hieawy A, Wang Z, Haapasalo M. Effect of Torsional and Fatigue Preloading on HyFlex EDM Files. J Endod 2018; 44:643-647. [DOI: 10.1016/j.joen.2017.12.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 11/29/2017] [Accepted: 12/01/2017] [Indexed: 11/28/2022]
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Mechanical and Metallurgical Properties of Various Nickel-Titanium Rotary Instruments. BIOMED RESEARCH INTERNATIONAL 2017; 2017:4528601. [PMID: 29318149 PMCID: PMC5727669 DOI: 10.1155/2017/4528601] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 10/27/2017] [Accepted: 11/02/2017] [Indexed: 11/26/2022]
Abstract
The aim of this study was to investigate the effect of thermomechanical treatment on mechanical and metallurgical properties of nickel-titanium (NiTi) rotary instruments. Eight kinds of NiTi rotary instruments with sizes of ISO #25 were selected: ProFile, K3, and One Shape for the conventional alloy; ProTaper NEXT, Reciproc, and WaveOne for the M-wire alloy; HyFlex CM for the controlled memory- (CM-) wire; and TF for the R-phase alloy. Torsional fracture and cyclic fatigue fracture tests were performed. Products underwent a differential scanning calorimetry (DSC) analysis. The CM-wire and R-phase groups had the lowest elastic modulus, followed by the M-wire group. The maximum torque of the M-wire instrument was comparable to that of a conventional instrument, while those of the CM-wire and R-phase instruments were lower. The angular displacement at failure (ADF) for the CM-wire and R-phase instruments was higher than that of conventional instruments, and ADF of the M-wire instruments was lower. The cyclic fatigue resistance of the thermomechanically treated NiTi instruments was higher. DSC plots revealed that NiTi instruments made with the conventional alloy were primarily composed of austenite at room temperature; stable martensite and R-phase were found in thermomechanically treated instruments.
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Miccoli G, Gaimari G, Seracchiani M, Morese A, Khrenova T, Di Nardo D. In vitro resistance to fracture of two nickel-titanium rotary instruments made with different thermal treatments. ANNALI DI STOMATOLOGIA 2017; 8:53-58. [PMID: 29299189 DOI: 10.11138/ads/2017.8.2.059] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Aim Aim of the study was to evaluate effectiveness of different heat treatments in improving Ni-Ti endodontic rotary instruments' resistance to fracture. Methods 24 new NiTi instruments similar in length and shape: 12 M3 instruments, tip size 25 and .06 taper (United Dental, Shanghai, China), and 12 M3 Pro Gold instruments tip size 25 and .06 taper (United Dental, Shanghai, China), were tested in a 60° curved artificial root canal. Each group received a different heat treatment. Cycles to fracture were calculated for each instrument. Differences among groups were evaluated with an analysis of variance test (significance level was set at P<0.05.). Results Statistical analysis found significant differences (p<0.0213) between groups. The M3 Pro Gold instruments were significantly more resistant to fatigue (mean values = 1012, SD +/- 77) than M3 instruments (mean values = 748, SD +/- 62). No statistically significant differences were found between fragments' lengths (p>0,05). Conclusions An increased flexibility and the reduction of internal defects produced by heat treatments during or after manufacturing processes, may be responsible for improving resistance to cyclic fatigue and flexural stresses.
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Affiliation(s)
- Gabriele Miccoli
- Department of Oral and Maxillo-Facial Sciences, "Sapienza" University of Rome, Rome, Italy
| | - Gianfranco Gaimari
- Department of Oral and Maxillo-Facial Sciences, "Sapienza" University of Rome, Rome, Italy
| | - Marco Seracchiani
- Department of Oral and Maxillo-Facial Sciences, "Sapienza" University of Rome, Rome, Italy
| | - Antonio Morese
- Department of Oral and Maxillo-Facial Sciences, "Sapienza" University of Rome, Rome, Italy
| | - Tatyana Khrenova
- Department of Oral and Maxillo-Facial Sciences, "Sapienza" University of Rome, Rome, Italy
| | - Dario Di Nardo
- Department of Oral and Maxillo-Facial Sciences, "Sapienza" University of Rome, Rome, Italy
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Ounsi HF, Nassif W, Grandini S, Salameh Z, Neelakantan P, Anil S. Evolution of Nickel-titanium Alloys in Endodontics. J Contemp Dent Pract 2017; 18:1090-1096. [PMID: 29109327 DOI: 10.5005/jp-journals-10024-2181] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
UNLABELLED To improve clinical use of nickel-titanium (NiTi) endodontic rotary instruments by better understanding the alloys that compose them. A large number of engine-driven NiTi shaping instruments already exists on the market and newer generations are being introduced regularly. While emphasis is being put on design and technique, manufacturers are more discreet about alloy characteristics that dictate instrument behavior. Along with design and technique, alloy characteristics of endodontic instruments is one of the main variables affecting clinical performance. Modification in NiTi alloys is numerous and may yield improvements, but also drawbacks. Martensitic instruments seem to display better cyclic fatigue properties at the expense of surface hardness, prompting the need for surface treatments. On the contrary, such surface treatments may improve cutting efficiency but are detrimental to the gain in cyclic fatigue resistance. Although the design of the instrument is vital, it should in no way cloud the importance of the properties of the alloy and how they influence the clinical behavior of NiTi instruments. CLINICAL SIGNIFICANCE Dentists are mostly clinicians rather than engineers. With the advances in instrumentation design and alloys, they have an obligation to deal more intimately with engineering consideration to not only take advantage of their possibilities but also acknowledge their limitations.
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Affiliation(s)
- Hani F Ounsi
- Department of Endodontics, Faculty of Dental Medicine Lebanese University, Beirut, Lebanon; Department of Endodontics and Restorative Dentistry, Siena University, Siena, Italy, e-mail:
| | - Wadih Nassif
- Department of Prosthodontics, Faculty of Dental Medicine Lebanese University, Beirut, Lebanon
| | - Simone Grandini
- Department of Endodontics and Restorative Dentistry, Siena University, Siena, Italy
| | - Ziad Salameh
- Department of Research, Faculty of Dental Medicine, Lebanese University, Beirut, Lebanon
| | - Prasanna Neelakantan
- Department of Endodontology, Faculty of Dentistry, The University of Hong Kong, Hong Kong
| | - Sukumaran Anil
- Department of Dental Health, Dental Biomaterials Research Chair, College of Applied Medical Sciences, King Saud University Riyadh, Kingdom of Saudi Arabia
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Peters OA, de Azevedo Bahia MG, Pereira ESJ. Contemporary Root Canal Preparation: Innovations in Biomechanics. Dent Clin North Am 2017; 61:37-58. [PMID: 27912818 DOI: 10.1016/j.cden.2016.08.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Root canal preparation must serve the goals of supporting debridement while exerting the least amount of structural damage. Toward those goals, several recent trends for innovation are noted: some changes in instrument design, several of them substantial, whereas others are rather discrete. In vitro testing is ongoing and, because of the lack of consistent methodology, gives only some guidelines for clinical use. Lastly, clinical outcome data are lacking for many current instruments; therefore, it is not clear if improvements in flexibility and resistance to fatigue will translate to better outcomes.
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Affiliation(s)
- Ove Andreas Peters
- Department of Endodontics, University of the Pacific Arthur A. Dugoni School of Dentistry, 155 5th Street, San Francisco, CA, USA.
| | - Maria Guiomar de Azevedo Bahia
- Department of Restorative Dentistry, Faculty of Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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Evidence for Reduced Fatigue Resistance of Contemporary Rotary Instruments Exposed to Body Temperature. J Endod 2016; 42:782-7. [DOI: 10.1016/j.joen.2016.01.025] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 01/28/2016] [Accepted: 01/31/2016] [Indexed: 11/15/2022]
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Shen Y, Zhou H, Coil JM, Aljazaeri B, Buttar R, Wang Z, Zheng YF, Haapasalo M. ProFile Vortex and Vortex Blue Nickel-Titanium Rotary Instruments after Clinical Use. J Endod 2015; 41:937-42. [DOI: 10.1016/j.joen.2015.02.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 01/31/2015] [Accepted: 02/03/2015] [Indexed: 11/26/2022]
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Wu H, Peng C, Bai Y, Hu X, Wang L, Li C. Shaping ability of ProTaper Universal, WaveOne and ProTaper Next in simulated L-shaped and S-shaped root canals. BMC Oral Health 2015; 15:27. [PMID: 25886847 PMCID: PMC4350914 DOI: 10.1186/s12903-015-0012-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 02/19/2015] [Indexed: 11/30/2022] Open
Abstract
Background The purpose of this study was to compare the shaping ability of the ProTaper Universal (PTU; Dentsply Maillefer, Ballaigues, Switzerland), WaveOne (WO; Dentsply Maillefer) and ProTaper Next (PTN; Dentsply Maillefer) in simulated L-shaped and S-shaped root canals respectively. Methods 30 simulated L-shaped and 30 simulated S-shaped root canals in resin blocks were employed and randomly divided into 3 groups (n = 10), respectively. The canals were prepared to a tip size 25 using PTU, WO or PTN: PTU F2 (taper 0.08 over the first 3 mm from apical tip), WO Primary (taper 0.08 over the first 3 mm from apical tip), and PTN X2 (taper 0.06 over the first 3 mm from apical tip). Photos of the simulated root canals were taken pre- and postinstrumentation. The 2 layers were superimposed after a series of image processing and 10 points were selected from apical constriction with 1 mm interval. And then the central axis transportation and straightened curvature were measured with software of image analysis. Results In simulated L-shaped root canals, PTU and PTN caused less transportation than WO at curved section (P < 0.05), and PTN caused the least transportation at apical constriction (P < 0.05). Moreover, PTN maintained the canal curvature best among the 3 groups (P < 0.05). But PTN produced more transportation at straight section compared with PTU and WO (P < 0.05). In simulated S-shaped root canals, PTN preserved the coronal curvature best (P < 0.05), but there was no significant difference in apical curvature since all the files straightened the curvature obviously. Conclusions PTN showed a better shaping ability than PTU and WO at the curved section of root canals, and PTN maintained the best apical constriction. But all the files had a tendency to straighten the apical curvature in multi-curved canals.
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Affiliation(s)
- Hui Wu
- School of Stomatology, Tianjin Medical University, #12 Qi Xiang Tai Road, He Ping District, Tianjin, 300070, PR China.
| | - Cheng Peng
- School of Stomatology, Tianjin Medical University, #12 Qi Xiang Tai Road, He Ping District, Tianjin, 300070, PR China. .,Department of Stomatology, The Second Hospital of Tianjin Medical University, Tianjin Medical University, Tianjin, China.
| | - Yulong Bai
- School of Stomatology, Tianjin Medical University, #12 Qi Xiang Tai Road, He Ping District, Tianjin, 300070, PR China.
| | - Xin Hu
- School of Stomatology, Tianjin Medical University, #12 Qi Xiang Tai Road, He Ping District, Tianjin, 300070, PR China.
| | - Lei Wang
- School of Stomatology, Tianjin Medical University, #12 Qi Xiang Tai Road, He Ping District, Tianjin, 300070, PR China.
| | - Changyi Li
- School of Stomatology, Tianjin Medical University, #12 Qi Xiang Tai Road, He Ping District, Tianjin, 300070, PR China.
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Shen Y, Zhou H, Campbell L, Wang Z, Wang R, Du T, Haapasalo M. Fatigue and nanomechanical properties of K3XF nickel-titanium instruments. Int Endod J 2014; 47:1160-7. [DOI: 10.1111/iej.12265] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 02/06/2014] [Indexed: 11/26/2022]
Affiliation(s)
- Y. Shen
- Division of Endodontics; Department of Oral Biological and Medical Sciences; Faculty of Dentistry; The University of British Columbia; Vancouver BC Canada
- Department of Materials Engineering; The University of British Columbia; Vancouver BC Canada
| | - H. Zhou
- Center for Biomedical Materials and Engineering; College of Material Science and Chemical Engineering; Harbin Engineering University; Harbin China
| | - L. Campbell
- Division of Endodontics; Department of Oral Biological and Medical Sciences; Faculty of Dentistry; The University of British Columbia; Vancouver BC Canada
| | - Z. Wang
- Division of Endodontics; Department of Oral Biological and Medical Sciences; Faculty of Dentistry; The University of British Columbia; Vancouver BC Canada
| | - R. Wang
- Department of Materials Engineering; The University of British Columbia; Vancouver BC Canada
| | - T. Du
- Department of Stomatology; Tongji Hospital; Tongji Medical College; Huazhong University of Science and Technology; Wuhan China
| | - M. Haapasalo
- Division of Endodontics; Department of Oral Biological and Medical Sciences; Faculty of Dentistry; The University of British Columbia; Vancouver BC Canada
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Electrochemical impedance spectroscopy investigation on the clinical lifetime of ProTaper rotary file system. BIOMED RESEARCH INTERNATIONAL 2014; 2014:754189. [PMID: 24605336 PMCID: PMC3925554 DOI: 10.1155/2014/754189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 11/11/2013] [Indexed: 11/18/2022]
Abstract
The main objective of the current paper is to show that electrochemical impedance spectroscopy (EIS) could be a method for evaluating and predicting of ProTaper rotary file system clinical lifespan. This particular aspect of everyday use of the endodontic files is of great importance in each dental practice and has profound clinical implications. The method used for quantification resides in the electrochemical impedance spectroscopy theory and has in its main focus the characteristics of the surface titanium oxide layer. This electrochemical technique has been adapted successfully to identify the quality of the Ni-Ti files oxide layer. The modification of this protective layer induces changes in corrosion behavior of the alloy modifying the impedance value of the file. In order to assess the method, 14 ProTaper sets utilized on different patients in a dental clinic have been submitted for testing using EIS. The information obtained in regard to the surface oxide layer has offered an indication of use and proves that the said layer evolves with each clinical application. The novelty of this research is related to an electrochemical technique successfully adapted for Ni-Ti file investigation and correlation with surface and clinical aspects.
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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: 1.5] [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: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Shen Y, Zhou HM, Zheng YF, Peng B, Haapasalo M. Current Challenges and Concepts of the Thermomechanical Treatment of Nickel-Titanium Instruments. J Endod 2013; 39:163-72. [DOI: 10.1016/j.joen.2012.11.005] [Citation(s) in RCA: 294] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 11/03/2012] [Accepted: 11/06/2012] [Indexed: 11/17/2022]
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Shen Y, Coil JM, Zhou H, Zheng Y, Haapasalo M. HyFlex nickel-titanium rotary instruments after clinical use: metallurgical properties. Int Endod J 2013; 46:720-9. [PMID: 23330612 DOI: 10.1111/iej.12049] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 12/12/2012] [Indexed: 12/30/2022]
Abstract
AIM To analyse the type and location of defects in HyFlex CM instruments after clinical use in a graduate endodontic programme and to examine the impact of clinical use on their metallurgical properties. METHODOLOGY A total of 468 HyFlex CM instruments discarded from a graduate endodontic programme were collected after use in three teeth. The incidence and type of instrument defects were analysed. The lateral surfaces of the defect instruments were examined by scanning electron microscopy. New and clinically used instruments were examined by differential scanning calorimetry (DSC) and x-ray diffraction (XRD). Vickers hardness was measured with a 200-g load near the flutes for new and clinically used axially sectioned instruments. Data were analysed using one-way anova or Tukey's multiple comparison test. RESULTS Of the 468 HyFlex instruments collected, no fractures were observed and 16 (3.4%) revealed deformation. Of all the unwound instruments, size 20, .04 taper unwound the most often (n = 5) followed by size 25, .08 taper (n = 4). The trend of DSC plots of new instruments and clinically used (with and without defects) instruments groups were very similar. The DSC analyses showed that HyFlex instruments had an austenite transformation completion or austenite-finish (Af ) temperature exceeding 37 °C. The Af temperatures of HyFlex instruments (with or without defects) after multiple clinical use were much lower than in new instruments (P < 0.05). The enthalpy values for the transformation from martensitic to austenitic on deformed instruments were smaller than in the new instruments at the tip region (P < 0.05). XRD results showed that NiTi instruments had austenite and martensite structure on both new and used HyFlex instruments at room temperature. No significant difference in microhardness was detected amongst new and used instruments (with and without defects). CONCLUSIONS The risk of HyFlex instruments fracture in the canal is very low when instruments are discarded after three cases of clinical use. New HyFlex instruments were a mixture of martensite and austenite structure at body temperature. Multiple clinical use caused significant changes in the microstructural properties of HyFlex instruments. Smaller instruments should be considered as single-use.
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Affiliation(s)
- Y Shen
- Division of Endodontics, Department of Oral Biological & Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, BC, Canada
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Mechanical Properties of Controlled Memory and Superelastic Nickel-Titanium Wires Used in the Manufacture of Rotary Endodontic Instruments. J Endod 2012; 38:1535-40. [DOI: 10.1016/j.joen.2012.07.006] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 07/13/2012] [Accepted: 07/26/2012] [Indexed: 11/23/2022]
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21
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Shen Y, Coil JM, Zhou HM, Tam E, Zheng YF, Haapasalo M. ProFile Vortex instruments after clinical use: a metallurgical properties study. J Endod 2012; 38:1613-7. [PMID: 23146647 DOI: 10.1016/j.joen.2012.09.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 09/19/2012] [Accepted: 09/24/2012] [Indexed: 11/18/2022]
Abstract
INTRODUCTION The aim of the study was to analyze the incidence and mode of ProFile Vortex instrument (Dentsply Tulsa Dental Specialties, Tulsa, OK) defects during a predefined schedule of clinical use by the undergraduate students in a dental school setting and to examine the metallurgical characteristics of unused and clinically used Vortex instruments. METHODS A total of 2,203 ProFile Vortex instruments discarded after single use from the undergraduate students program over 24 months were collected and examined for defects using a stereomicrosocpe at 10× magnification. The incidence and type of instrument defects or separation were analyzed. The lateral surfaces of part of the defected instruments and fracture surfaces of fractured files were examined using scanning electron microscopy. Unused and clinically used files were examined by differential scanning calorimetry and X-ray diffraction. Vickers hardness of the files was measured with a 200-g load. RESULTS Only 1 of the 2,203 files fractured during clinical use. The cause of fracture was shear stress, and the file also showed unwinding of the helix structure. None of the remaining 2,202 files exhibited unwinding after clinical use. Blunt apicals were detected in 86 used files (3.9%). Austenite-finish temperatures were very similar for as-received, used files with defects and used files without defects, all exceeding 50°C. No difference in microhardness was detected among these 3 instrument groups. X-ray diffraction results showed that NiTi files had austenite structure at room temperature. CONCLUSIONS The risk of ProFile Vortex fracture is very low when files are used 1 time by undergraduate students. Unwinding of the files was not detected except for the fractured file. Clinical single use had no detectable effect on austenite-martensite phase transformation of the files. Unused and clinical single-use files contain a similar phase structure at body temperature.
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Affiliation(s)
- Ya Shen
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, Canada
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Metallurgical Characterization of Controlled Memory Wire Nickel-Titanium Rotary Instruments. J Endod 2011; 37:1566-71. [DOI: 10.1016/j.joen.2011.08.005] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 07/05/2011] [Accepted: 08/02/2011] [Indexed: 11/19/2022]
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Gutmann JL, Gao Y. Alteration in the inherent metallic and surface properties of nickel-titanium root canal instruments to enhance performance, durability and safety: a focused review. Int Endod J 2011; 45:113-28. [PMID: 21902705 DOI: 10.1111/j.1365-2591.2011.01957.x] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The expanded use of nickel-titanium (NiTi) rotary instruments in root canal procedures has led to the development of a wide variety of shapes, designs and applications. Root canal anatomy has not changed, however, and the same challenges exist in both initial treatment and the revision of unacceptable treatment. These challenges include application with high levels of achievement and low to no levels of adverse effects, such as instrument fracture, root canal wall ledging, dentine wall perforation and so forth. To that end, many manufacturers have been seeking ways to alter the presently available and wide range of root canal instrument designs, with a focus on altering the surface of the alloy or altering the alloy microstructure with post-machining or post-twisting heat treatment. This focused review will address the impact that these modifications have had on instrument flexibility, resistance to cyclic fatigue and cutting efficiency.
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Affiliation(s)
- J L Gutmann
- Baylor College of Dentistry, Texas A&M Health Science Center, Dallas, TX, USA.
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Condorelli GG, Bonaccorso A, Smecca E, Schäfer E, Cantatore G, Tripi TR. Improvement of the fatigue resistance of NiTi endodontic files by surface and bulk modifications. Int Endod J 2010; 43:866-73. [DOI: 10.1111/j.1365-2591.2010.01759.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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