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Zheng J, Aarts JM, Ma S, Waddell JN, Choi JJE. Different Undercut Depths Influence on Fatigue Behavior and Retentive Force of Removable Partial Denture Clasp Materials: A Systematic Review. J Prosthodont 2023; 32:108-115. [PMID: 35405767 DOI: 10.1111/jopr.13519] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 03/31/2022] [Indexed: 11/28/2022] Open
Abstract
PURPOSE To perform a systematic review that provides an overview of the current literature on fatigue behavior of removable partial denture (RPD) clasp materials based on different retentive areas. MATERIALS AND METHODS The review followed the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. Electronic searches were done via PubMed, Scopus, and OVID for studies reporting on RPD clasps and the fatigue failure of clasp materials. Inclusion criteria were English language with full text and in vitro studies only. Exclusion criteria were studies that did not assess the fatigue of RPD clasp materials. A quality assessment and selection of full-text articles were performed according to Consolidated Standards of Reporting Trials criteria. RESULTS A total of 182 articles were initially identified and screened. After applying inclusion and exclusion criteria, 15 articles were selected for the final analysis. Seven of the included studies utilized a vertical insertion/removal testing approach. Ten studies used the constant deflection test. Three studies used untapered specimens, and 12 studies used tapered specimens. Ten studies performed post-test analysis. CONCLUSIONS Cobalt-chromium (CoCr) is the strongest material in terms of fatigue in relation to the undercut depth and the modern, digitally manufactured RPD clasp materials also exhibit comparable fatigue behavior. Recent RPD clasp materials such as polyetheretherketone (PEEK) or laser sintered CoCr, however, require further study in terms of their fatigue behavior. In order to improve the quality of future studies, a standardized and calibrated fatigue testing method is needed with standardized specimen size and shape, which will reduce the risk of bias and enable meta-analysis for bulk comparison between studies.
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Affiliation(s)
- Jenny Zheng
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - John M Aarts
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Sunyoung Ma
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - John Neil Waddell
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Joanne Jung Eun Choi
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
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Zheng J, Aarts JM, Ma S, Waddell JN, Choi JJE. Fatigue behavior of removable partial denture cast and laser-sintered cobalt-chromium (CoCr) and polyetheretherketone (PEEK) clasp materials. Clin Exp Dent Res 2022; 8:1496-1504. [PMID: 35938907 PMCID: PMC9760146 DOI: 10.1002/cre2.645] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/23/2022] [Accepted: 07/31/2022] [Indexed: 01/26/2023] Open
Abstract
OBJECTIVE To investigate the fatigue behavior of cast and laser-sintered cobalt-chromium (CoCr) and polyetheretherketone (PEEK) material for a removable partial denture (RPD) clasps. METHODS Dumbbell-shaped specimens were digitally designed with the center part of the dumbbell being a half-round shape at the cross-sectional dimension of 1.25 mm to simulate a typical clasp design and dimensions. A fatigue machine with an offset axis rotation system simulated a typical undercut depth of 0.25, 0.50, and 0.75 mm. Each group was subjected to 30,000 fatigue cycles (simulating 21 years) or till specimen failure. Before testing, the stress value at each undercut depth for each specimen was established in a universal testing machine and SN curves were plotted for each group. Data were statistically analyzed using Kruskal-Wallis and post hoc tests. The fractured surfaces were analyzed using SEM. RESULTS The average fatigue cycles with 0.25, 0.50, and 0.75 mm undercuts were 27,155 ± 6277, 9298 ± 4033, 5642 ± 8785 for cast CoCr and 26,765 ± 6150, 11,318 ± 7931, 2861 ± 4803, for laser-sintered CoCr, respectively. Apart from three specimens, the PEEK groups did not fail during the simulation period. Clasps with 0.25 mm deflection showed significantly higher fatigue resistance than other groups (p < .001). There was no significant difference in fatigue behavior between the cast and laser-sintered CoCr. Microporosities at the fractured site along with irregular crack propagation were observed for cast and laser-sintered CoCr specimens. Fatigue-induced broken polymer crosslinking chains were observed in PEEK specimens. CONCLUSION PEEK material exhibited the highest fatigue resistance and significantly lower deflection resistance. Cast and laser-sintered CoCr showed similar fatigue resistance and behavior.
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Affiliation(s)
- Jenny Zheng
- Faculty of Dentistry, Sir John Walsh Research InstituteUniversity of OtagoDunedinNew Zealand
| | - John M. Aarts
- Faculty of Dentistry, Sir John Walsh Research InstituteUniversity of OtagoDunedinNew Zealand
| | - Sunyoung Ma
- Faculty of Dentistry, Sir John Walsh Research InstituteUniversity of OtagoDunedinNew Zealand
| | - John N. Waddell
- Faculty of Dentistry, Sir John Walsh Research InstituteUniversity of OtagoDunedinNew Zealand
| | - Joanne J. E. Choi
- Faculty of Dentistry, Sir John Walsh Research InstituteUniversity of OtagoDunedinNew Zealand
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马 珂, 陈 虎, 沈 妍, 周 永, 王 勇, 孙 玉. [Finite element analyses of retention of removable partial denture circumferential clasps manufactured by selective laser melting]. BEIJING DA XUE XUE BAO. YI XUE BAN = JOURNAL OF PEKING UNIVERSITY. HEALTH SCIENCES 2022; 54:105-112. [PMID: 35165476 PMCID: PMC8860646 DOI: 10.19723/j.issn.1671-167x.2022.01.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Indexed: 06/14/2023]
Abstract
OBJECTIVE To compare the retentions of different designs of cobalt-chromium (Co-Cr), pure titanium (CP Ti), and titanium alloy (Ti-6Al-4V) removable partial denture (RPD) circumferential clasps manufactured by selective laser melting (SLM) and to analyze the stress distribution of these clasps during the removal from abutment teeth. METHODS Clasps with clasp arm size A (1.9 mm width/1.1 mm thickness at the body and 0.8-taper) or B (1.2 times A) and 0.25 mm or 0.50 mm undercut engagement were modeled on a prepared first premolar die, named as designs A1, A2, A3, and A4, respectively. The density and elastic modulus of SLM-built Co-Cr, CP Ti, and Ti-6Al-4V were measured and given to different groups of clasps. The density, elastic modulus, and Poisson ' s ratio of enamel were given to the die. The control group was the cast Co-Cr clasp with design A1, to which the density and elastic modulus of cast Co-Cr alloy were given. The Poisson's ratio of all metals was 0.33. The initial 5 N dislodging force was applied, and the maximum displacement of the clasp along the insertion path was computed. The load was reapplied with an increment of 5 N than in the last simulation until the clasp was completely dislodged. The retentive force range of different groups of clasps was obtained. The retentive forces of the SLM-built Co-Cr, CP Ti, and Ti-6Al-4V clasps with equivalent computed retentive force range to the control group were validated through the insertion/removal experiment. The von Mises stress distributions of these three groups of SLM-built clasps under 15 N loads were analyzed. RESULTS SLM-built Co-Cr, CP Ti, and Ti-6Al-4V clasps with designs B1 or B2, and Co-Cr clasps with design A2 had higher retentive forces than those of the control group. SLM-built CP Ti and Ti-6Al-4V clasps with design A1 had lower retentive forces than those of the control group. SLM-built Co-Cr clasp with design A1 and SLM-built CP Ti and Ti-6Al-4V clasps with design A2 had equivalent retentive forces to those of the control group. The insertion/removal experiment showed that the measured retentive forces of these three groups of SLM-built clasps were (21.57±5.41) N, (19.75±4.47) N, and (19.32±2.04) N, respectively. No statistically significant measured retentive force difference was found among these three groups of SLM-built clasps (P>0.05). The maximum von Mises stress of these three groups of SLM-built clasps exceeded their responding yield strength except for the Ti-6Al-4V one. CONCLUSION SLM-built Co-Cr circumferential clasps had higher retention than CP Ti and Ti-6Al-4V ones with the same clasp arm size and undercut engagement. The retention of SLM-built circumferential clasps could be adjusted by changing the undercut engagement and clasp arm size. If SLM-built circumferential clasps are used in clinical practice, the Ti-6Al-4V clasp with clasp arm size A and 0.50 mm undercut engagement is recommended considering the long-term use of RPD in the patient's mouth.
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Affiliation(s)
- 珂楠 马
- 北京大学医学部医学技术研究院,北京 100191Institute of Medical Technology, Peking University Health Science Center, Beijing 100191
- 北京大学口腔医学院·口腔医院口腔医学数字化研究中心,口腔修复教研室,国家口腔医学中心,国家口腔疾病临床医学研究中心,口腔数字化医疗技术和材料国家工程实验室,口腔数字医学北京市重点实验室,国家卫生健康委员会口腔医学计算机应用工程技术研究中心,国家药品监督管理局口腔材料重点实验室,北京 100081Center of Digital Dentistry, Faculty of Prosthodontics, Peking University School and Hospital of Stomatology & National Center 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 & NHC Research Center of Engineering and Technology for Computerized Dentistry & NMPA Key Laboratory for Dental Materials, Beijing 100081, China
| | - 虎 陈
- 北京大学口腔医学院·口腔医院口腔医学数字化研究中心,口腔修复教研室,国家口腔医学中心,国家口腔疾病临床医学研究中心,口腔数字化医疗技术和材料国家工程实验室,口腔数字医学北京市重点实验室,国家卫生健康委员会口腔医学计算机应用工程技术研究中心,国家药品监督管理局口腔材料重点实验室,北京 100081Center of Digital Dentistry, Faculty of Prosthodontics, Peking University School and Hospital of Stomatology & National Center 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 & NHC Research Center of Engineering and Technology for Computerized Dentistry & NMPA Key Laboratory for Dental Materials, Beijing 100081, China
| | - 妍汝 沈
- 北京大学口腔医学院·口腔医院口腔医学数字化研究中心,口腔修复教研室,国家口腔医学中心,国家口腔疾病临床医学研究中心,口腔数字化医疗技术和材料国家工程实验室,口腔数字医学北京市重点实验室,国家卫生健康委员会口腔医学计算机应用工程技术研究中心,国家药品监督管理局口腔材料重点实验室,北京 100081Center of Digital Dentistry, Faculty of Prosthodontics, Peking University School and Hospital of Stomatology & National Center 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 & NHC Research Center of Engineering and Technology for Computerized Dentistry & NMPA Key Laboratory for Dental Materials, Beijing 100081, China
| | - 永胜 周
- 北京大学口腔医学院·口腔医院口腔修复科,国家口腔医学中心,国家口腔疾病临床医学研究中心,口腔数字化医疗技术和材料国家工程实验室,口腔数字医学北京市重点实验室,国家卫生健康委员会口腔医学计算机应用工程技术研究中心,国家药品监督管理局口腔材料重点实验室,北京 100081Department of Prosthodontics, Peking University School and Hospital of Stomatology & National Center 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 & NHC Research Center of Engineering and Technology for Computerized Dentistry & NMPA Key Laboratory for Dental Materials, Beijing 100081, China
| | - 勇 王
- 北京大学口腔医学院·口腔医院口腔医学数字化研究中心,口腔修复教研室,国家口腔医学中心,国家口腔疾病临床医学研究中心,口腔数字化医疗技术和材料国家工程实验室,口腔数字医学北京市重点实验室,国家卫生健康委员会口腔医学计算机应用工程技术研究中心,国家药品监督管理局口腔材料重点实验室,北京 100081Center of Digital Dentistry, Faculty of Prosthodontics, Peking University School and Hospital of Stomatology & National Center 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 & NHC Research Center of Engineering and Technology for Computerized Dentistry & NMPA Key Laboratory for Dental Materials, Beijing 100081, China
| | - 玉春 孙
- 北京大学医学部医学技术研究院,北京 100191Institute of Medical Technology, Peking University Health Science Center, Beijing 100191
- 北京大学口腔医学院·口腔医院口腔医学数字化研究中心,口腔修复教研室,国家口腔医学中心,国家口腔疾病临床医学研究中心,口腔数字化医疗技术和材料国家工程实验室,口腔数字医学北京市重点实验室,国家卫生健康委员会口腔医学计算机应用工程技术研究中心,国家药品监督管理局口腔材料重点实验室,北京 100081Center of Digital Dentistry, Faculty of Prosthodontics, Peking University School and Hospital of Stomatology & National Center 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 & NHC Research Center of Engineering and Technology for Computerized Dentistry & NMPA Key Laboratory for Dental Materials, Beijing 100081, China
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Micovic D, Mayinger F, Bauer S, Roos M, Eichberger M, Stawarczyk B. Is the high-performance thermoplastic polyetheretherketone indicated as a clasp material for removable dental prostheses? Clin Oral Investig 2020; 25:2859-2866. [PMID: 33026523 PMCID: PMC8060225 DOI: 10.1007/s00784-020-03603-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 09/23/2020] [Indexed: 11/29/2022]
Abstract
Objectives To investigate the retention force of polyetheretherketone (PEEK) removable dental prosthesis clasps in comparison with a cobalt-chrome-molybdenum control group after storage in artificial saliva. Materials and Methods Clasps were milled (Dentokeep (PEEKmilled1), NT digital implant technology; breCAM BioHPP Blank (PEEKmilled2), bredent), pressed (BioHPP Granulat for 2 press (PEEKpressed), bredent), or cast (remanium GM 800+ (cobalt-chrome-molybdenum), Dentaurum); N = 60, n = 15/subgroup. Retention force was examined 50 times/specimen in a pull-off test using the universal testing machine (Zwick 1445), where pull-off force was applied with a crosshead speed of 5 mm/minute until the maximum force dropped by 10%, at different aging levels: (1) initial, after storage in artificial saliva for (2) 90 and (3) 180 days. Statistical analysis was performed using one-way ANOVA followed by post hoc Scheffé-test and mixed models (p < 0.05). Results Cobalt-chrome-molybdenum presented the highest retention force. No differences were observed between polyetheretherketone materials. Cobalt-chrome-molybdenum showed a significant decrease of its values after artificial aging, while polyetheretherketone materials presented similar results over the course of aging. Regarding a repetitive insertion and removal, even though PEEKmilled2 and cobalt-chrome-molybdenum showed an initial increase, ultimately, a decrease in retention force was observed for all tested groups. Conclusions Although the control group showed significantly higher results, the retention force of polyetheretherketone materials indicate a potential clinical application. Neither the manufacturing process nor artificial aging showed an impact on the retention force of polyetheretherketone clasps. Clinical relevance Mechanical properties of novel removable dental prosthesis clasp materials devised to meet the growing esthetic demands of patients need to be investigated to ensure a successful long-term clinical application.
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Affiliation(s)
- Danka Micovic
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Felicitas Mayinger
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany.
| | - Sebastian Bauer
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Malgorzata Roos
- Department of Biostatistics, Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Hirschengraben 84, 8001, Zurich, Switzerland
| | - Marlis Eichberger
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany
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Tan FB, Song JL, Wang C, Fan YB, Dai HW. Titanium clasp fabricated by selective laser melting, CNC milling, and conventional casting: a comparative in vitro study. J Prosthodont Res 2019; 63:58-65. [DOI: 10.1016/j.jpor.2018.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 08/07/2018] [Accepted: 08/11/2018] [Indexed: 10/28/2022]
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Kajima Y, Takaichi A, Nakamoto T, Kimura T, Yogo Y, Ashida M, Doi H, Nomura N, Takahashi H, Hanawa T, Wakabayashi N. Fatigue strength of Co-Cr-Mo alloy clasps prepared by selective laser melting. J Mech Behav Biomed Mater 2016; 59:446-458. [PMID: 26974490 DOI: 10.1016/j.jmbbm.2016.02.032] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 01/12/2016] [Accepted: 02/26/2016] [Indexed: 11/18/2022]
Abstract
We aimed to investigate the fatigue strength of Co-Cr-Mo clasps for removable partial dentures prepared by selective laser melting (SLM). The Co-Cr-Mo alloy specimens for tensile tests (dumbbell specimens) and fatigue tests (clasp specimens) were prepared by SLM with varying angles between the building and longitudinal directions (i.e., 0° (TL0, FL0), 45° (TL45, FL45), and 90° (TL90, FL90)). The clasp specimens were subjected to cyclic deformations of 0.25mm and 0.50mm for 10(6) cycles. The SLM specimens showed no obvious mechanical anisotropy in tensile tests and exhibited significantly higher yield strength and ultimate tensile strength than the cast specimens under all conditions. In contrast, a high degree of anisotropy in fatigue performance associated with the build orientation was found. For specimens under the 0.50mm deflection, FL90 exhibited significantly longer fatigue life (205,418 cycles) than the cast specimens (112,770 cycles). In contrast, the fatigue lives of FL0 (28,484 cycles) and FL45 (43,465 cycles) were significantly shorter. The surface roughnesses of FL0 and FL45 were considerably higher than those of the cast specimens, whereas there were no significant differences between FL90 and the cast specimens. Electron backscatter diffraction (EBSD) analysis indicated the grains of FL0 showed preferential close to <001> orientation of the γ phase along the normal direction to the fracture surface. In contrast, the FL45 and FL90 grains showed no significant preferential orientation. Fatigue strength may therefore be affected by a number of factors, including surface roughness and crystal orientation. The SLM process is a promising candidate for preparing tough removable partial denture frameworks, as long as the appropriate build direction is adopted.
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Affiliation(s)
- Yuka Kajima
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Atsushi Takaichi
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
| | - Takayuki Nakamoto
- Machining & Molding Section, Technology Research Institute of Osaka Prefecture, 2-7-1 Ayumino, Izumi, Osaka 594-1157, Japan
| | - Takahiro Kimura
- Machining & Molding Section, Technology Research Institute of Osaka Prefecture, 2-7-1 Ayumino, Izumi, Osaka 594-1157, Japan
| | - Yoshiaki Yogo
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Maki Ashida
- Metallic Biomaterials, Biomedical Materials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062, Japan
| | - Hisashi Doi
- Metallic Biomaterials, Biomedical Materials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062, Japan
| | - Naoyuki Nomura
- Metallurgy, Materials Science and Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02 Aramaki-aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Hidekazu Takahashi
- Oral Biomaterials Development Engineering, Course for Oral Health Engineering, School of Oral Health Care Sciences, Faculty of Dentistry, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Takao Hanawa
- Metallic Biomaterials, Biomedical Materials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062, Japan
| | - Noriyuki Wakabayashi
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
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Fatigue resistance and retentive force of cast clasps treated by shot peening. J Prosthodont Res 2013; 57:186-94. [PMID: 23809297 DOI: 10.1016/j.jpor.2013.01.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 12/26/2012] [Accepted: 01/29/2013] [Indexed: 11/23/2022]
Abstract
PURPOSE The fatigue failure of denture clasps has often been observed in removable partial denture rehabilitation. To increase their fatigue strength, shot peening was evaluated as a surface treatment. In this study, we evaluated the fatigue resistance and retention of cast clasps by using a shot peening treatment. METHODS A cobalt-chromium (Co-Cr) alloy, commercial pure titanium (CP Ti), silver-palladium-gold (Ag-Pd-Au), and a gold-platinum (Au-Pt) alloy were cast and then treated with shot peening. The retentive forces of the clasps were measured up to a repetition of 10,000insertion/removal cycles in distilled water at 37°C. A fatigue test was also performed using a 15-mm cantilever. Specimens were loaded with a constant deflection of 2.0mm with 20Hz. A shot peening treatment indicated a better stability of retentive forces than that without shot peening. The retentive force of Co-Cr clasps without shot peening was remarkably decreased at 500 cycles of insertion/removal repetition. RESULTS The clasps with a shot peening treatment provided approximately 1.4-3.6 times higher fatigue strengths than those without a shot peening treatment. CONCLUSION To prevent the fatigue failure of the denture clasps and use the dentures for long term, a shot peening treatment would be recommended.
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Retentive forces and fatigue resistance of thermoplastic resin clasps. Dent Mater 2012; 28:273-8. [DOI: 10.1016/j.dental.2011.10.016] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Revised: 09/06/2011] [Accepted: 10/29/2011] [Indexed: 11/18/2022]
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Nonlinear finite element analyses: Advances and challenges in dental applications. J Dent 2008; 36:463-71. [PMID: 18455859 DOI: 10.1016/j.jdent.2008.03.010] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2008] [Revised: 03/26/2008] [Accepted: 03/26/2008] [Indexed: 01/13/2023] Open
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