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Agrawal PR, Chandak M, Nikhade PP, Patel AS, Bhopatkar JK. Revolutionizing endodontics: Advancements in nickel-titanium instrument surfaces. JOURNAL OF CONSERVATIVE DENTISTRY AND ENDODONTICS 2024; 27:126-133. [PMID: 38463467 PMCID: PMC10923218 DOI: 10.4103/jcde.jcde_248_23] [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: 10/28/2023] [Revised: 11/19/2023] [Accepted: 12/05/2023] [Indexed: 03/12/2024]
Abstract
Nickel-titanium (NiTi) instruments have become the backbone of endodontics due to their exceptional properties, superelasticity, and shape memory. However, challenges such as unexpected breakage, poor cutting efficiency, and corrosion have prompted researchers to explore innovative surface modifications to enhance their performance. This comprehensive review discusses the latest advancements in NiTi metallurgy and their impact on rotary NiTi file systems. Various surface treatment techniques, including ion implantation, cryogenic treatment (CT), thermal nitridation, electropolishing, and physical or chemical vapor deposition, have been investigated to minimize defects, boost surface hardness, and improve cyclic fatigue resistance. Ion implantation has shown promise by increasing wear resistance and cutting efficiency through nitrogen ion incorporation. Thermal nitridation has successfully formed titanium nitride (TiN) coatings, resulting in improved corrosion resistance and cutting efficiency. CT has demonstrated increased cutting efficiency and overall strength by creating a martensite transformation and finer carbide particles. Electropolishing has yielded mixed results, providing smoother surfaces but varying impacts on fatigue resistance. Physical or chemical vapor deposition has proven effective in forming TiN coatings, enhancing hardness and wear resistance. Furthermore, the concept of surface functionalization with silver ions for antibacterial properties has been explored. These advancements present an exciting future for endodontic procedures, offering the potential for enhanced NiTi instruments with improved performance, durability, and patient outcomes.
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Affiliation(s)
- Paridhi Rajesh Agrawal
- Department of Conservative Dentistry and Endodontics, DMIHER, Sharad Pawar Dental College and Hospital, Wardha, Maharashtra, India
| | - Manoj Chandak
- Department of Conservative Dentistry and Endodontics, DMIHER, Sharad Pawar Dental College and Hospital, Wardha, Maharashtra, India
| | - Pradnya Prashant Nikhade
- Department of Conservative Dentistry and Endodontics, DMIHER, Sharad Pawar Dental College and Hospital, Wardha, Maharashtra, India
| | - Aditya Satyawansingh Patel
- Department of Conservative Dentistry and Endodontics, DMIHER, Sharad Pawar Dental College and Hospital, Wardha, Maharashtra, India
| | - Jay Kailas Bhopatkar
- Department of Conservative Dentistry and Endodontics, DMIHER, Sharad Pawar Dental College and Hospital, Wardha, Maharashtra, India
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Chan WS, Gulati K, Peters OA. Advancing Nitinol: From heat treatment to surface functionalization for nickel–titanium (NiTi) instruments in endodontics. Bioact Mater 2023; 22:91-111. [PMID: 36203965 PMCID: PMC9520078 DOI: 10.1016/j.bioactmat.2022.09.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 09/04/2022] [Accepted: 09/09/2022] [Indexed: 11/27/2022] Open
Abstract
Nickel-titanium (NiTi) alloy has been extensively researched in endodontics, particularly in cleaning and shaping the root canal system. Research advances have primarily focused on the design, shape, and geometry of the NiTi files as well as metallurgy and mechanical properties. So far, extensive investigations have been made surrounding surface and thermomechanical treatments, however, limited work has been done in the realm of surface functionalization to augment its performance in endodontics. This review summarizes the unique characteristics, current use, and latest developments in thermomechanically treated NiTi endodontic files. It discusses recent improvements in nano-engineering and the possibility of customizing the NiTi file surface for added functionalization. Whilst clinical translation of this technology has yet to be fully realized, future research direction will lie in the use of nanotechnology. Nitinol (Nickel Titanium alloy) is widely used to clean/shape root canal system in endodontics. To enhance its performance, various thermo-mechanical and nano-engineering modifications have been performed. This comprehensive review summarizes the latest advances and future trends relating to functionalized NiTi endodontic files.
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Hu X, Zhao G, Du J, Ye N. Mechanical properties analysis of medical endodontic instruments based on parameterization. J Mech Behav Biomed Mater 2022; 134:105416. [PMID: 36037707 DOI: 10.1016/j.jmbbm.2022.105416] [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: 06/05/2022] [Revised: 08/06/2022] [Accepted: 08/08/2022] [Indexed: 11/19/2022]
Abstract
To study the relationship between structural parameters and mechanical properties of endodontic instruments, the T02004B25 nickel-titanium endodontic instrument was selected for bending and torsion tests and finite element simulation analysis, which demonstrated the feasibility of simulation analysis method. Then based on the idea of parametric design, the models of the endodontic instruments with different structural parameters (cross-section, pitch, taper) were established, and the bending-torsion performance simulation analysis was completed. The results showed that the mechanical properties of endodontic instruments with different structural parameters are different. It is necessary to find the optimal parameters for different structure parameters of endodontic instruments to maximize their service life.
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Affiliation(s)
- Xiulin Hu
- Key Laboratory of Advanced Design and Simulation Technology for Special Equipment Ministry of Education, Hunan University, Changsha, 410082, China.
| | - Gongwei Zhao
- Key Laboratory of Advanced Design and Simulation Technology for Special Equipment Ministry of Education, Hunan University, Changsha, 410082, China.
| | - Jiachen Du
- Key Laboratory of Advanced Design and Simulation Technology for Special Equipment Ministry of Education, Hunan University, Changsha, 410082, China.
| | - Nanhai Ye
- Key Laboratory of Advanced Design and Simulation Technology for Special Equipment Ministry of Education, Hunan University, Changsha, 410082, China.
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Cryotherapy: A New Paradigm of Treatment in Endodontics. J Endod 2020; 46:936-942. [DOI: 10.1016/j.joen.2020.03.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 02/27/2020] [Accepted: 03/15/2020] [Indexed: 02/08/2023]
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Abstract
Ever since their introduction, nickel–titanium (NiTi) alloys have continued to revolutionize the field of endodontics. They have considerable advantages over the conventional stainless steel file in terms of mechanical properties. However, despite of their superior mechanical properties, NiTi alloys still pose some risk of fracture. Consequently, there has been considerable research conducted to investigate the mechanisms behind the occurrence of these procedural errors. Since the last decade, different proprietary processing procedures have been introduced to further improve the mechanical properties of NiTi alloys. These treatments include thermal, mechanical, electropolishing, and recently introduced electric discharge machining. The main purpose of these treatments is to impart a more martensitic phase into the files at normal body temperature, so that the maximum advantage of flexibility can be obtained. These heat-treated instruments also possess improved cyclic fatigue resistance when compared to conventional NiTi alloys. NiTi alloys can be subclassified as the instruments mainly containing austenitic phase (conventional NiTi, M-wire, R-phase), and those containing martensitic phase (controlled memory wire, ProTaper Gold, and Vortex Blue). Instruments based on austenitic alloys possess superelastic properties due to the stress-induced martensitic transformation. Contrary to this, martensitic alloys can easily be deformed due to phase transformation, and they can demonstrate the shape memory effect when heated. This review discusses the different phase transformations and heat treatments that the NiTi instruments undergo.
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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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Al Jabbari YS, Koutsoukis T, Al Hadlaq S, Berzins DW, Zinelis S. Surface and cross-sectional characterization of titanium-nitride coated nickel-titanium endodontic files. J Dent Sci 2016; 11:48-53. [PMID: 30894945 PMCID: PMC6395189 DOI: 10.1016/j.jds.2015.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 06/25/2015] [Indexed: 11/30/2022] Open
Abstract
Background/purpose Although the effect of experimental surface modifications on various properties (e.g., fatigue, wear) on coated files have been tested in the past, there is no report for the coating quality of commercially available TiN coated files. The aim of this study was to characterize the surface and cross section of TiN coated endodontic files. Materials and methods TiN coated nickel–titanium endodontic files (EasyShape) were surface and cross-sectionally analyzed via scanning electron microscopy backscattered electron imaging and energy-dispersive X-ray spectroscopy analysis in spot, area, and line scan modes. Results Surface imaging revealed parallel oblong regions with higher mean atomic contrast, a finding attributed to increased Ni content. Cross-sectional analysis showed that the coating’s average total thickness was 0.31 μm and consisted of a thin layered film. Energy-dispersive X-ray spectroscopy analysis revealed the presence of Ti, Ni, N, and O in the coating, whereas only Ni and Ti were identified in the bulk of the file. Ti and O showed their peak compositions at the bulk/coating and coating/surface interfaces, respectively, whereas N displayed a rather constant content within the coated region. The N and O contents started increasing inner to the coating/bulk interface, denoting possible diffusion of both elements to the subcoating region. Conclusion Surface and bulk characterization showed no uncoated areas of the files tested. Apart from Ti, Ni, and N, oxygen was also identified within the coating region.
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Affiliation(s)
- Youssef S Al Jabbari
- Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, P.O. Box 60169, Riyadh 11545, Saudi Arabia.,Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, P.O. Box 60169, Riyadh 11545, Saudi Arabia
| | - Theodoros Koutsoukis
- Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, P.O. Box 60169, Riyadh 11545, Saudi Arabia
| | - Suliman Al Hadlaq
- Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, P.O. Box 60169, Riyadh 11545, Saudi Arabia.,Department of Restorative Dental Sciences, College of Dentistry, King Saud University, P.O. Box 60169, Riyadh 11545, Saudi Arabia
| | - David W Berzins
- Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, P.O. Box 60169, Riyadh 11545, Saudi Arabia.,Department of Dental Biomaterials, School of Dentistry, Marquette University, Milwaukee, WI, USA
| | - Spiros Zinelis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, 2 Thivon Street, Goudi 11527, Athens, Greece.,Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, P.O. Box 60169, Riyadh 11545, Saudi Arabia
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Constant Insertion Rate Methodology for Measuring Torque and Apical Force in 3 Nickel-Titanium Instruments with Different Cross-sectional Designs. J Endod 2015. [DOI: 10.1016/j.joen.2015.05.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Cutting Efficiency of Conventional and Martensitic Nickel-Titanium Instruments for Coronal Flaring. J Endod 2013; 39:1634-8. [DOI: 10.1016/j.joen.2013.08.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 08/04/2013] [Accepted: 08/05/2013] [Indexed: 11/30/2022]
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Bürklein S, Schäfer E. Critical evaluation of root canal transportation by instrumentation. ACTA ACUST UNITED AC 2013. [DOI: 10.1111/etp.12043] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Spagnuolo G, Ametrano G, D'Antò V, Rengo C, Simeone M, Riccitiello F, Amato M. Effect of autoclaving on the surfaces of TiN-coated and conventional nickel-titanium rotary instruments. Int Endod J 2012; 45:1148-55. [DOI: 10.1111/j.1365-2591.2012.02088.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 05/27/2012] [Indexed: 11/29/2022]
Affiliation(s)
- G. Spagnuolo
- Department of Oral and Maxillofacial Sciences; University of Napoli “Federico II”; Napoli; Italy
| | - G. Ametrano
- Department of Oral and Maxillofacial Sciences; University of Napoli “Federico II”; Napoli; Italy
| | - V. D'Antò
- Department of Oral and Maxillofacial Sciences; University of Napoli “Federico II”; Napoli; Italy
| | - C. Rengo
- Department of Oral and Maxillofacial Sciences; University of Napoli “Federico II”; Napoli; Italy
| | - M. Simeone
- Department of Oral and Maxillofacial Sciences; University of Napoli “Federico II”; Napoli; Italy
| | - F. Riccitiello
- Department of Oral and Maxillofacial Sciences; University of Napoli “Federico II”; Napoli; Italy
| | - M. Amato
- Department of Medical School; University of Salerno; Salerno; Italy
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Gao Y, Gutmann JL, Wilkinson K, Maxwell R, Ammon D. Evaluation of the Impact of Raw Materials on the Fatigue and Mechanical Properties of ProFile Vortex Rotary Instruments. J Endod 2012; 38:398-401. [DOI: 10.1016/j.joen.2011.11.004] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 11/01/2011] [Accepted: 11/17/2011] [Indexed: 11/26/2022]
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George GK, Sanjeev K, Sekar M. An in vitro evaluation of the effect of deep dry cryotreatment on the cutting efficiency of three rotary nickel titanium instruments. J Conserv Dent 2011; 14:169-72. [PMID: 21814360 PMCID: PMC3146111 DOI: 10.4103/0972-0707.82627] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 10/23/2010] [Accepted: 11/19/2010] [Indexed: 11/04/2022] Open
Abstract
CONTEXT Cryogenic methods have been used to increase the strength of metals. AIM The aim of this study was to evaluate the effect of deep dry cryotherapy on the cyclic fatigue resistance of rotary nickel titanium instruments. MATERIALS AND METHODS Twenty K3, RaCe and Hero Shaper nickel titanium instruments, size 25, 0.06 taper, were taken for this study. Ten files were untreated (control group) and 10 files were deep dry cryogenically treated. Both the untreated and cryotreated files were subjected to cyclic fatigue evaluation. Cyclic fatigue was evaluated as the number of cycles it took for fracture of the instrument within a stainless steel shaping block of specific radius and angle of curvature. STATISTICAL ANALYSIS Mean values were compared between different study groups by using one-way analysis of variance (ANOVA) with P < 0.05 considered as the level of significance. RESULTS The results showed a significant increase in the resistance to cyclic fatigue of deep dry cryotreated NiTi files over untreated files. CONCLUSIONS It may thus be concluded that deep cryotherapy has improved the cyclic fatigue of NiTi rotary endodontic files.
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Affiliation(s)
- Gingu Koshy George
- Department of Conservative Dentistry and Endodontics, Pushpagiri Dental College, Thiruvalla, India
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Bürklein S, Hiller C, Huda M, Schäfer E. Shaping ability and cleaning effectiveness of Mtwo versus coated and uncoated EasyShape instruments in severely curved root canals of extracted teeth. Int Endod J 2011; 44:447-57. [DOI: 10.1111/j.1365-2591.2011.01850.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Wan J, Rasimick BJ, Musikant BL, Deutsch AS. Cutting efficiency of 3 different instrument designs used in reciprocation. ACTA ACUST UNITED AC 2010; 109:e82-5. [DOI: 10.1016/j.tripleo.2009.12.037] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 12/03/2009] [Accepted: 12/23/2009] [Indexed: 11/29/2022]
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Taira Y, Hatono H, Tokita M, Sawase T. Thickness and surface structure of a ceramic layer created on three indirect resin composites with aerosol deposition. J Prosthodont Res 2010; 54:168-72. [PMID: 20399175 DOI: 10.1016/j.jpor.2010.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 02/28/2010] [Accepted: 03/18/2010] [Indexed: 11/16/2022]
Abstract
PURPOSE Aerosol deposition is a technology for coating ceramics with impact consolidation at room temperature. The aim of the present study was to investigate the thickness and the microstructure of the aluminium oxide layer on different three dental resin composite materials created by means of aerosol deposition. METHODS Disk-shaped specimens were fabricated with three resin composites (Estenia C&B, Targis, and Gradia). The specimens were ground flat, and then subjected to aerosol deposition using aluminium oxide submicron particles without inducing a localized temperature rise. The average thickness (AVH) and maximum thickness (Hmax) of the aluminium oxide layer deposited on the resin composite material were measured using a profilometer. Data were analyzed by ANOVA and post hoc Tukey compromise test at α=0.05. The specimen surfaces were also observed using a scanning electron microscope. RESULTS The aluminium oxide layer formed on Estenia C&B (AVH 8.1 μm, Hmax 9.1 μm) and Targis (AVH 7.7 μm, Hmax 8.9 μm) were significantly thicker than that on Gradia (AVH 4.2 μm, Hmax 5.4 μm). The micrograph showed that the aluminium oxide layer on Estenia C&B was similar to that on Targis. However, the aerosol deposition area of Gradia was seen relatively rough and partly caved. CONCLUSIONS The type of resin composite affected the microstructure of the deposited aluminium oxide layer. The highly filled light- and heat-cured resin composites are advantageous as a target material rather than the lower filled light-cured resin composite.
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Affiliation(s)
- Yohsuke Taira
- Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan.
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Vaudt J, Bitter K, Neumann K, Kielbassa AM. Ex vivo study on root canal instrumentation of two rotary nickel-titanium systems in comparison to stainless steel hand instruments. Int Endod J 2009; 42:22-33. [PMID: 19125977 DOI: 10.1111/j.1365-2591.2008.01489.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM To investigate instrumentation time, working safety and the shaping ability of two rotary nickel-titanium (NiTi) systems (Alpha System and ProTaper Universal) in comparison to stainless steel hand instruments. METHODOLOGY A total of 45 mesial root canals of extracted human mandibular molars were selected. On the basis of the degree of curvature the matched teeth were allocated randomly into three groups of 15 teeth each. In group 1 root canals were prepared to size 30 using a standardized manual preparation technique; in group 2 and 3 rotary NiTi instruments were used following the manufacturers' instructions. Instrumentation time and procedural errors were recorded. With the aid of pre- and postoperative radiographs, apical straightening of the canal curvature was determined. Photographs of the coronal, middle and apical cross-sections of the pre- and postoperative canals were taken, and superimposed using a standard software. Based on these composite images the portion of uninstrumented canal walls was evaluated. RESULTS Active instrumentation time of the Alpha System was significantly reduced compared with ProTaper Universal and hand instrumentation (P < 0.05; anova). No instrument fractures occurred in any of the groups. The Alpha System revealed significantly less apical straightening compared with the other instruments (P < 0.05; Mann-Whitney U test). In the apical cross-sections Alpha System resulted in significantly less uninstrumented canal walls compared with stainless steel files (P < 0.05; chi-squared test). CONCLUSION Despite the demonstrated differences between the systems, an apical straightening effect could not be prevented; areas of uninstrumented root canal wall were left in all regions using the various systems.
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Affiliation(s)
- J Vaudt
- Department of Operative Dentistry and Periodontology, University School of Dental Medicine, CharitéCentrum 3, Charité - Universitätsmedizin Berlin, Berlin, Germany.
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Zinelis S, Akhtar R, Tsakiridis P, Watts DC, Silikas N. In-depth hardness profiles of Stainless Steel and Ni-Ti endodontic instrument cross-sections by nano-indentation. Int Endod J 2008; 41:747-54. [DOI: 10.1111/j.1365-2591.2008.01426.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Three-dimensional Analysis of Cutting Behavior of Nickel-Titanium Rotary Instruments by Microcomputed Tomography. J Endod 2008; 34:606-10. [DOI: 10.1016/j.joen.2008.02.025] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2007] [Revised: 02/18/2008] [Accepted: 02/25/2008] [Indexed: 11/23/2022]
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Cutting Efficiency of Five Different Types of Rotary Nickel–Titanium Instruments. J Endod 2008; 34:198-200. [DOI: 10.1016/j.joen.2007.10.009] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Revised: 10/02/2007] [Accepted: 10/20/2007] [Indexed: 11/23/2022]
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Bui TB, Mitchell JC, Baumgartner JC. Effect of Electropolishing ProFile Nickel–Titanium Rotary Instruments on Cyclic Fatigue Resistance, Torsional Resistance, and Cutting Efficiency. J Endod 2008; 34:190-3. [DOI: 10.1016/j.joen.2007.10.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 10/16/2007] [Accepted: 10/23/2007] [Indexed: 11/30/2022]
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Vinothkumar TS, Miglani R, Lakshminarayananan L. Influence of Deep Dry Cryogenic Treatment on Cutting Efficiency and Wear Resistance of Nickel–Titanium Rotary Endodontic Instruments. J Endod 2007; 33:1355-8. [DOI: 10.1016/j.joen.2007.07.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Revised: 06/21/2007] [Accepted: 07/15/2007] [Indexed: 10/22/2022]
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Parashos P, Messer HH. Rotary NiTi Instrument Fracture and its Consequences. J Endod 2006; 32:1031-43. [PMID: 17055902 DOI: 10.1016/j.joen.2006.06.008] [Citation(s) in RCA: 309] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2006] [Revised: 06/08/2006] [Accepted: 06/08/2006] [Indexed: 11/26/2022]
Abstract
The fracture of endodontic instruments is a procedural problem creating a major obstacle to normally routine therapy. With the advent of rotary nickel-titanium (NiTi) instruments this issue seems to have assumed such prominence as to be a considerable hindrance to the adoption of this major technical advancement. Considerable research has been undertaken to understand the mechanisms of failure of NiTi alloy to minimize its occurrence. This has led to changes in instrument design, instrumentation protocols, and manufacturing methods. In addition, factors related to clinician experience, technique, and competence have been shown to be influential. From an assessment of the literature presented, we derive clinical recommendations concerning prevention and management of this complication.
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Affiliation(s)
- Peter Parashos
- School of Dental Science, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia.
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Taira Y, Hatono H, Mizukane M, Tokita M, Atsuta M. Effect of Ceramic Coating by Aerosol Deposition on Abrasion Resistance of a Resin Composite Material. Dent Mater J 2006; 25:700-5. [PMID: 17338303 DOI: 10.4012/dmj.25.700] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Aerosol deposition (AD coating) is a novel technique to coat solid substances with a ceramic film. The purpose of the present study was to investigate the effect of AD coating on abrasion resistance of a resin composite material. A 5-microm-thick aluminum oxide layer was created on the polymerized resin composite. The specimen was cyclically abraded using a toothbrush abrasion simulator for 100,000 cycles. Abraded surface was then measured with a profilometer to determine the average roughness (Ra) and maximum roughness (Rmax). It was found that abrasion cycling increased the Ra value of the No-AD-coating group, but decreased the Ra and Rmax values of the AD coating group. Moreover, the AD coating group showed significantly smaller Ra and Rmax values after 100,000 abrasion cycles as compared to the No-coating control group. Microscopic observation supported these findings. In conclusion, the resistance of the resin composite against toothbrush abrasion was improved by AD coating.
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Affiliation(s)
- Yohsuke Taira
- Division of Applied Prosthodontics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
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Kim JW, Griggs JA, Regan JD, Ellis RA, Cai Z. Effect of cryogenic treatment on nickel-titanium endodontic instruments. Int Endod J 2005; 38:364-71. [PMID: 15910471 PMCID: PMC1266290 DOI: 10.1111/j.1365-2591.2005.00945.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM To investigate the effects of cryogenic treatment on nickel-titanium endodontic instruments. The null hypothesis was that cryogenic treatment would result in no changes in composition, microhardness or cutting efficiency of nickel-titanium instruments. METHODOLOGY Microhardness was measured on 30 nickel-titanium K-files (ISO size 25) using a Vicker's indenter. Elemental composition was measured on two instruments using X-ray spectroscopy. A nickel-titanium bulk specimen was analysed for crystalline phase composition using X-ray diffraction. Half of the specimens to be used for each analysis were subjected to a cryogenic treatment in liquid nitrogen (-196 degrees C) for either 3 s (microhardness specimens) or 10 min (other specimens). Cutting efficiency was assessed by recording operator choice using 80 nickel-titanium rotary instruments (ProFile 20, .06) half of which had been cryogenically treated and had been distributed amongst 14 clinicians. After conditioning by preparing four corresponding canals, each pair of instruments were evaluated for cutting efficiency by a clinician during preparation of one canal system in vitro. A Student's t-test was used to analyse the microhardness data, and a binomial test was used to analyse the observer choice data. Composition data were analysed qualitatively. RESULTS Cryogenically treated specimens had a significantly higher microhardness than the controls (P < 0.001; beta > 0.999). Observers showed a preference for cryogenically treated instruments (61%), but this was not significant (P = 0.21). Both treated and control specimens were composed of 56% Ni, 44% Ti, 0% N (by weight) with a majority in the austenite phase. CONCLUSIONS Cryogenic treatment resulted in increased microhardness, but this increase was not detected clinically. There was no measurable change in elemental or crystalline phase composition.
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Affiliation(s)
- J. W. Kim
- Departments of Graduate Endodontics and
| | - J. A. Griggs
- Biomaterials Science, Baylor College of Dentistry, Texas A&M University System, Health Science Center, Dallas, TX, USA
- Correspondence: J. A. Griggs, 3302 Gaston Avenue, Dallas, TX 75246, USA (Tel.: +1 214 828 8307; fax: +1 214 828 8458; e-mail:
)
| | | | | | - Z. Cai
- Biomaterials Science, Baylor College of Dentistry, Texas A&M University System, Health Science Center, Dallas, TX, USA
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Abstract
The introduction of nickel-titanium (NiTi) as material for endodontic instruments about 15 years ago opened many new perspectives. Many dentists and scientists see a benefit in using NiFi files. Initial problems such as frequent fractures and the uncertainty of the best way to use them have been solved. Other challenges such as enhancing the cutting ability or optimizing the speed, torque, and fatigue are currently being addressed. Some clinicians are skeptical because they see this approach as too mechanical. Nevertheless, the combination of anatomic, biologic, and pathophysiologic knowledge with the use of NiTi instruments is a large step forward in optimizing the quality of root canal treatment worldwide.
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Affiliation(s)
- Michael A Baumann
- Department of Operative Dentistry and Periodontology, Dental School, University of Cologne, Kerpener Strasse 32, D-50931 Köln, Germany
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