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Ogami K, Hagio M, Ueda T. Maxillary Obturator Prosthesis Made with Polyetherketoneketone Using Optical Impression and CAD/CAM System. THE BULLETIN OF TOKYO DENTAL COLLEGE 2023; 64:31-37. [PMID: 36792151 DOI: 10.2209/tdcpublication.2022-0020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
This report describes the case of a 68-year-old man who visited our department complaining of poor denture retention and difficulty masticating due to damage to the retainer of a maxillary obturator. The patient had never been satisfied with the fit of this prosthesis, which had been placed two years earlier. The obturator and the mucosal surface of the denture base were incompatible, which had caused the retainer to detach. The maxillary defect was categorized as H3S0D0T0 according to the HS classification. The diagnosis was a masticatory disorder due to a damaged retainer and an incompatible denture base. Optical impressions and occlusal records were taken and a maxillary obturator fabricated using a CAD/CAM system. Dental CAD software was used to design and complete the tooth arrangement. The CAM system was used to mill a polyetherketoneketone disc based on the obtained data and composite resin used to face the teeth and gingiva. The maxillary obturator was placed after only three visits, spanning from impression taking to denture completion. The use of digital data allowed the time to denture completion to be shortened in addition to the number of hospital visits to be reduced. Compared to conventional impression taking, optical impressions also prevent discomfort, decreasing stress for the patient.
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Affiliation(s)
- Koichiro Ogami
- Division of General Dentistry, Chiba Dental Center, Tokyo Dental College
| | - Miki Hagio
- Department of Removable Prosthodontics & Gerodontology, Tokyo Dental College
| | - Takayuki Ueda
- Department of Removable Prosthodontics & Gerodontology, Tokyo Dental College
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Vaddamanu SK, Alhamoudi FH, Chaturvedi S, Alqahtani NM, Addas MK, Alfarsi MA, Vyas R, Kanji MA, Zarbah MA, Alqahtani WMS, Alqahtani SM, Abdelmonem AM, Elmahdi AE. Retentive Forces and Deformation of Fitting Surface in RPD Clasp Made of Polyether-Ether-Ketone (PEEK). Polymers (Basel) 2023; 15:polym15040956. [PMID: 36850239 PMCID: PMC9959771 DOI: 10.3390/polym15040956] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/04/2023] [Accepted: 02/03/2023] [Indexed: 02/17/2023] Open
Abstract
BACKGROUND Polyetheretherketone (PEEK) has provided the option to fabricate RPDs with aesthetics unlike metal RPDs, but little attention has been paid to its suitability, especially towards the retentive forces and deformation of the clasp. This study aimed to examine the retentive forces and the fitting surface (inner surface) deformation of clasps made from PEEK and compare it with cobalt-chromium (Co-Cr) clasp. METHODS Forty-two circumferential clasps (14 Co-Cr and 28 PEEK) were fabricated and divided into two groups with clasp undercuts (0.25 mm and 0.5 mm) with thicknesses of 1 mm and 1.5 mm. Each was examined for retentive forces after cycle test on its abutment for 360 cycles. Initial and final retentive forces were recorded. The fitting surface deformation was determined using 3-Matic research analysis software. RESULTS The results revealed that highest mean initial retentive force was of Co-Cr clasps with 0.50 mm undercut 22.26 N (±10.15 N), and the lowest was the 1 mm PEEK clasps with 0.25 mm undercut 3.35 N (±0.72 N) and highest mean final retentive force was the Co-Cr clasps with 0.50 mm undercut 21.40 N (±9.66 N), and the lowest was the 1 mm PEEK clasps with 0.25 mm undercut 2.71 N (±0.47 N). PEEK clasps had a lower retentive force than Co-Cr clasps with 0.50 undercut. PEEK clasps (1.5 mm) at 0.25 mm undercut had the least deformation (35.3 µm). PEEK showed significantly less deformation (p ≤ 0.014) than Co-Cr. CONCLUSION The deformation of PEEK clasps fitting surface was lower than Co-Cr clasps and retentive forces were close to the Co-Cr clasps, suggesting the use of PEEK as an aesthetic clasp option for RPD framework.
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Affiliation(s)
- Sunil Kumar Vaddamanu
- Department of Dental Technology, College of Applied Medical Sciences, King Khalid University, Abha 61421, Saudi Arabia
- Correspondence: (S.K.V.); (S.C.); Tel.: +966-595220377 (S.K.V.); +966-580697248 (S.C.)
| | - Fahad Hussain Alhamoudi
- Department of Dental Technology, College of Applied Medical Sciences, King Khalid University, Abha 61421, Saudi Arabia
| | - Saurabh Chaturvedi
- Department of Prosthetic Dentistry, College of Dentistry, King Khalid University, Abha 61421, Saudi Arabia
- Correspondence: (S.K.V.); (S.C.); Tel.: +966-595220377 (S.K.V.); +966-580697248 (S.C.)
| | - Nasser M. Alqahtani
- Department of Prosthetic Dentistry, College of Dentistry, King Khalid University, Abha 61421, Saudi Arabia
| | - Mohamed Khaled Addas
- Department of Prosthetic Dentistry, College of Dentistry, King Khalid University, Abha 61421, Saudi Arabia
| | - Mohammad Al Alfarsi
- Department of Prosthetic Dentistry, College of Dentistry, King Khalid University, Abha 61421, Saudi Arabia
| | - Rajesh Vyas
- Department of Dental Technology, College of Applied Medical Sciences, King Khalid University, Abha 61421, Saudi Arabia
| | - Masroor Ahmed Kanji
- Department of Dental Technology, College of Applied Medical Sciences, King Khalid University, Abha 61421, Saudi Arabia
| | - Mohammad A. Zarbah
- Department of Prosthetic Dentistry, College of Dentistry, King Khalid University, Abha 61421, Saudi Arabia
| | - Waleed M. S. Alqahtani
- Department of Prosthetic Dentistry, College of Dentistry, King Khalid University, Abha 61421, Saudi Arabia
| | - Saeed M. Alqahtani
- Department of Prosthetic Dentistry, College of Dentistry, King Khalid University, Abha 61421, Saudi Arabia
| | - Adel M. Abdelmonem
- Department of Prosthetic Dentistry, College of Dentistry, King Khalid University, Abha 61421, Saudi Arabia
| | - Asim Elsir Elmahdi
- Department of Prosthetic Dentistry, College of Dentistry, King Khalid University, Abha 61421, Saudi Arabia
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Güleryüz A, Korkmaz C, Şener A, Taş MO. The effect of thermo-mechanical fatigue on the retentive force and dimensional changes in polyetheretherketone clasps with different thickness and undercut. J Adv Prosthodont 2021; 13:304-315. [PMID: 34777720 PMCID: PMC8558577 DOI: 10.4047/jap.2021.13.5.304] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/03/2021] [Accepted: 10/18/2021] [Indexed: 11/26/2022] Open
Abstract
PURPOSE Esthetic expectations have increased the use of polyetheretherketone (PEEK) clasps as alternatives to Cr-Co in removable partial dentures (RPDs). The objective of this study was to evaluate the retentive force and dimensional change of clasps with different thickness and undercut made from PEEK by the thermo-mechanical fatigue. MATERIALS AND METHODS PEEK clasps (N = 48) with thicknesses of 1 or 1.50 mm and 48 premolar monolithic zirconia crowns with undercuts of 0.25 mm or 0.50 mm were fabricated. Samples are divided into four groups (C1-C4) and were subjected to 7200 thermal aging cycles (at 5 - 55℃). The changes in the retentive force and dimensions of the clasps were measured by micro-stress testing and micro-CT devices from five measurement points (M1 - M5). One-way ANOVA, paired t-test, two-way repeated ANOVA, and post-hoc tests were used to analyze the data (P < .05). RESULTS The retentive forces of C1, C2, C3, and C4 groups in initial and final test were found to be 4.389-3.388 N, 4.67 - 3.396 N, 5.161 - 4.096 N, 5.459 - 4.141 N, respectively. The effects of retentive force of all PEEK clasps groups were significant decreased. Thermo-mechanical cycles caused significant dimensional changes at points with M2, M4, and M5, and abraded the clasp corners and increased the distance between the ends of the clasp, resulting in reduced retentive forces (P* = .016, P* = .042, P < .001, respectively). CONCLUSION Thermo-mechanical aging decreases the retentive forces in PEEK clasps. Increasing the thickness and undercut amount of clasps decreases the amount of dimensional change. The values measured after aging are within the clinically acceptable limits.
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Affiliation(s)
- Ayşegül Güleryüz
- Department of Prosthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey
| | - Cumhur Korkmaz
- Department of Prosthodontics, Faculty of Dentistry, University of Health Sciences, Istanbul, Turkey
| | - Ayşe Şener
- Republic of Turkey Ministry of Health, Ankara, Turkey
| | - Mehmet Ozan Taş
- Department of Prosthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey
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Richert R, Alsheghri AA, Alageel O, Caron E, Song J, Ducret M, Tamimi F. Analytical model of I-bar clasps for removable partial dentures. Dent Mater 2021; 37:1066-1072. [PMID: 33867171 DOI: 10.1016/j.dental.2021.03.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 02/26/2021] [Accepted: 03/29/2021] [Indexed: 01/23/2023]
Abstract
OBJECTIVE Clasps of removable partial dentures (RPDs) often suffer from fatigue stress that leads to plastic deformation, loss of retention, and RPD failure. Recently, computer-based technologies were proposed to optimize clasp geometry design. The objective of this study was to create an analytic model of I-bar clasps for computer-aided design (CAD)-RPD. METHODS The analytical model based on mechanical laws was established to simulate I-bar clasp retention, and optimize its design. The model considered the lengths of the vertical (L1) and horizontal (L2) arms of the I-bar as well as the radius (r) of its half-round cross-section. The analytical model was validated with mechanical experiments evaluating the retention of cobalt-chromium (Co-Cr) clasps in vitro and compared with finite element analysis (FEA). RESULTS The analytical model was in good agreement with the mechanical experiments and FEA, and showed that I-bar clasp design could provide optimal mechanical performance as long as the length of arms (L1 and L2) do not exceed 6 mm. Clasps with L1 > 8 mm and L2 > 9 mm presented stress values exceeding the fatigue limit of Co-Cr. The proposed solution was to increase the radius of I-bar to conserve the initial mechanical performance of Co-Cr. SIGNIFICANCE Co-Cr I-bar clasps perform best on teeth with reduced mesiodistal dimensions (canine and premolar), and their designs could be optimized to prevent stress from reaching the yield strength and the fatigue failure limit.
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Affiliation(s)
- Raphaël Richert
- Hospices Civils de Lyon, PAM Odontologie, Lyon, France; Faculté d'Odontologie, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France; Laboratoire de Mécanique des Contacts et structures, UMR 5259 CNRS/INSA Lyon, Lyon, France
| | - Ammar A Alsheghri
- Department of Mining Materials Engineering, McGill University, Montreal, QC, Canada; Department of Software and Computer Engineering, Polytechnique Montréal, Montréal, QC, Canada
| | - Omar Alageel
- Faculty of Dentistry, McGill University, Montreal, QC, Canada; King Saud University, Riyadh, Saudi Arabia
| | | | - Jun Song
- Department of Mining Materials Engineering, McGill University, Montreal, QC, Canada
| | - Maxime Ducret
- Hospices Civils de Lyon, PAM Odontologie, Lyon, France; Faculté d'Odontologie, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France; Faculty of Dentistry, McGill University, Montreal, QC, Canada
| | - Faleh Tamimi
- College of Dental Medicine, Qatar University, Doha, Qatar.
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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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Yamazaki T, Murakami N, Suzuki S, Handa K, Yatabe M, Takahashi H, Wakabayashi N. Influence of block-out on retentive force of thermoplastic resin clasps: an in vitro experimental and finite element analysis. J Prosthodont Res 2019; 63:303-308. [PMID: 30704930 DOI: 10.1016/j.jpor.2019.01.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 01/01/2019] [Accepted: 01/08/2019] [Indexed: 10/27/2022]
Abstract
PURPOSE The purpose of this study was to determine the effect of block-out preparation, used to eliminate the undercut area, on the retentive force and stress distribution of resin clasps. METHODS A total of 72 polyester and polyamide resin clasps were fabricated on a premolar abutment crown following six block-out preparations. A combination of two types of vertical block-outs and three types of horizontal block-outs (on the missing side) was used on the abutment tooth. Each clasp was subjected to an in vitro removal test using a universal testing machine. The retentive force and traces of the clasp on the abutment tooth were recorded and analyzed with one-way analysis of variance and post hoc comparisons (α=0.05). Non-linear finite element analysis was performed to assess the stress distributions of the resin clasps. RESULTS Resin clasps with a vertical block-out of 0.75mm undercut showed significantly higher retentive force than those with the 0.5mm undercut. Resin clasps with horizontal block-out showed significantly lower retentive force than those without horizontal block-out. There was no significant difference between the two thermoplastic resins. The maximum first principal stress of the resin clasp was concentrated under the shoulder of the clasp and strongly influenced by the width of horizontal block-out in the finite element analysis. CONCLUSIONS This in vitro experiment suggested that a horizontal block-out is necessary even for a 0.5-mm undercut. The design of the resin clasp should be considered from two aspects: retentive force and deformation risk.
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Affiliation(s)
- Toshiki Yamazaki
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Natsuko Murakami
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
| | - Shizuka Suzuki
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kazuyuki Handa
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Masaru Yatabe
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hidekazu Takahashi
- Oral Biomaterials Development Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Noriyuki Wakabayashi
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
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Alsheghri AA, Alageel O, Caron E, Ciobanu O, Tamimi F, Song J. An analytical model to design circumferential clasps for laser-sintered removable partial dentures. Dent Mater 2018; 34:1474-1482. [PMID: 29937332 DOI: 10.1016/j.dental.2018.06.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 04/05/2018] [Accepted: 06/07/2018] [Indexed: 10/28/2022]
Abstract
OBJECTIVE Clasps of removable partial dentures (RPDs) often suffer from plastic deformation and failure by fatigue; a common complication of RPDs. A new technology for processing metal frameworks for dental prostheses based on laser-sintering, which allows for precise fabrication of clasp geometry, has been recently developed. This study sought to propose a novel method for designing circumferential clasps for laser-sintered RPDs to avoid plastic deformation or fatigue failure. METHODS An analytical model for designing clasps with semicircular cross-sections was derived based on mechanics. The Euler-Bernoulli elastic curved beam theory and Castigliano's energy method were used to relate the stress and undercut with the clasp length, cross-sectional radius, alloy properties, tooth type, and retention force. Finite element analysis (FEA) was conducted on a case study and the resultant tensile stress and undercut were compared with the analytical model predictions. Pull-out experiments were conducted on laser-sintered cobalt-chromium (Co-Cr) dental prostheses to validate the analytical model results. RESULTS The proposed circumferential clasp design model yields results in good agreement with FEA and experiments. The results indicate that Co-Cr circumferential clasps in molars that are 13mm long engaging undercuts of 0.25mm should have a cross-section radius of 1.2mm to provide a retention of 10N and to avoid plastic deformation or fatigue failure. However, shorter circumferential clasps such as those in premolars present high stresses and cannot avoid plastic deformation or fatigue failure. SIGNIFICANCE Laser-sintered Co-Cr circumferential clasps in molars are safe, whereas they are susceptible to failure in premolars.
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Affiliation(s)
- Ammar A Alsheghri
- Department of Mining Materials Engineering, McGill University, Montreal, QC, Canada.
| | - Omar Alageel
- Faculty of Dentistry, McGill University, Montreal, QC, Canada; College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
| | | | - Ovidiu Ciobanu
- Faculty of Dentistry, McGill University, Montreal, QC, Canada.
| | - Faleh Tamimi
- Faculty of Dentistry, McGill University, Montreal, QC, Canada.
| | - Jun Song
- Department of Mining Materials Engineering, McGill University, Montreal, QC, Canada.
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Aly Sadek S, Dehis WM, Hassan H. Comparative Study Clarifying the Most Suitable Material to Be Used as Partial Denture Clasps. Open Access Maced J Med Sci 2018; 6:1111-1119. [PMID: 29983813 PMCID: PMC6026407 DOI: 10.3889/oamjms.2018.226] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/08/2018] [Accepted: 05/03/2018] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Removable partial denture's clasp is of particular importance as it affects the denture longevity during the function. The key of successful clasp selection is to select a direct retainer that will control tipping and torquing forces on the abutment teeth, provide retention against reasonable dislodging forces and are compatible with both tooth and tissue contour and the aesthetic desire of the patient. In this consideration, different materials employed for the clasp construction were compared mechanically. AIM This study aims to compare the most usable esthetic clasps mechanically to clarify the most suitable material to be used as partial denture clasps. METHODS Evaluation of surface roughness, retention and deformation has been investigated utilising different in-vitro methods. All these techniques provide valuable information regarding the mechanical properties of the materials tested. However, none of the in-vitro techniques can expose the tested materials to conditions similar to that of the oral environment (in-vivo) such as pH value and temperature variations. RESULTS Most commonly, RPD clasps are fabricated from the same alloy of the metal framework, as cobalt-chromium (CoCr) alloy although it is unaesthetic. Other methods consumed to avoid such esthetic mystery have included coating retainers with tooth-coloured resin or introduction of esthetic materials as Thermoplastic Acetal, Versacryl, and Thermopress. CONCLUSION It has been concluded that the non-metal Acetal resin retainer reveals superior mechanical properties.
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Affiliation(s)
- Sherif Aly Sadek
- Department of Prosthodontics, Faculty of Oral and Dental Medicine, Cairo University, Cairo, Egypt
| | - Wessam Mohamed Dehis
- Department of Fixed and Removable Prosthodontics, National Research Center, Cairo, Egypt
| | - Hala Hassan
- Department of Prosthodontics, Faculty of Oral and Dental Medicine, MTI University, Cairo, Egypt
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Nagakura M, Tanimoto Y, Nishiyama N. Effect of fiber content on flexural properties of glass fiber-reinforced polyamide-6 prepared by injection molding. Dent Mater J 2017; 36:415-421. [PMID: 28190814 DOI: 10.4012/dmj.2016-252] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The use of non-metal clasp denture (NMCD) materials may seriously affect the remaining tissues because of the low rigidity of NMCD materials such as polyamides. The purpose of this study was to develop a high-rigidity glass fiber-reinforced thermoplastic (GFRTP) composed of E-glass fiber and polyamide-6 for NMCDs using an injection molding. The reinforcing effects of fiber on the flexural properties of GFRTPs were investigated using glass fiber content ranging from 0 to 50 mass%. Three-point bending tests indicated that the flexural strength and elastic modulus of a GFRTP with a fiber content of 50 mass% were 5.4 and 4.7 times higher than those of unreinforced polyamide-6, respectively. The result showed that the physical characteristics of GFRTPs were greatly improved by increasing the fiber content, and the beneficial effects of fiber reinforcement were evident. The findings suggest that the injection-molded GFRTPs are adaptable to NMCDs because of their excellent mechanical properties.
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Affiliation(s)
- Manamu Nagakura
- Department of Dental Biomaterials, Nihon University School of Dentistry at Matsudo
| | - Yasuhiro Tanimoto
- Department of Dental Biomaterials, Nihon University School of Dentistry at Matsudo
| | - Norihiro Nishiyama
- Department of Dental Biomaterials, Nihon University School of Dentistry at Matsudo
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10
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Osada H, Shimpo H, Hayakawa T, Ohkubo C. Influence of thickness and undercut of thermoplastic resin clasps on retentive force. Dent Mater J 2014; 32:381-9. [PMID: 23718997 DOI: 10.4012/dmj.2012-284] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Thermoplastic resin clasps have been used for esthetic denture rehabilitation. However, details of the design of the clasps have never been thoroughly clarified. This study investigated the retentive forces of thermoplastic resin clasps for non-metal clasp dentures. The retentive forces of all thermoplastic resin clasps depended on the elastic modulus of each resin, undercuts, thickness, and widths of the tested. A clasp with more than 0.5 mm undercut and 1.0 mm thickness is needed for Valplast. Similarly, more than 0.25 mm undercut and 1.0 mm thickness and 0.5 mm undercut and 0.5 mm thickness are required for Estheshot and Reigning, respectively; thus, the recommended clasp arm thickness is 1.0 mm to 1.5 mm for Valplast and Estheshot and 0.5 mm to 1.0 mm for Reigning when the width of the retentive arm is 5.0 mm.
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Affiliation(s)
- Hidekazu Osada
- Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Kanagawa 230- 8501, Japan.
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11
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Kohorst P, Dittmer MP, Stiesch M. Enhancement of the adhesion between cobalt-base alloys and veneer ceramic by application of an oxide dissolving primer. Dent Mater 2013; 29:1295-302. [PMID: 24183053 DOI: 10.1016/j.dental.2013.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Revised: 07/18/2013] [Accepted: 10/07/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVES Uncontrolled formation of an oxide layer on base metal alloy surface impairs adhesion between the alloy and veneer ceramic. The aim of this study was to investigate the influence of an oxide dissolving primer on the adhesion between cobalt-base alloys and a veneer ceramic. METHODS Combinations of two cobalt-base alloys (Bärlight/BL, Cara Process/CP) and one veneering ceramic (HeraCeram) were investigated. 40 rectangular specimens of each alloy were covered with the veneer ceramic; half of the alloy samples were treated with an oxide dissolving primer (NP-Primer) prior to veneering (n=20). Subsequently, the veneering surface was ground flat and notched using the single-edge V-notched-beam method. Then specimens were loaded in a four-point bending test and the critical load to induce stable crack extension at the adhesion interface was determined, in order to calculate the strain energy release rate (G, J/m(2)). Finally, fracture surfaces of the specimens were evaluated by scanning electron microscopy (SEM). RESULTS Strain energy release rates averaged between 24.1J/m(2) and 28.8 J/m(2). While application of the primer statistically significantly increased adhesion between alloy and ceramic with the BL specimens (p=0.035), no significant influence was found for the CP specimens (p=0.785). For both material combinations, SEM analysis revealed enhanced wetting of the alloy surfaces with ceramic after application of the primer. SIGNIFICANCE Application of an oxide dissolving primer increases the wettability of cobalt-base alloy surfaces and thus improves adhesion to veneering ceramics. This may enhance the long-term stability of bilayer restorations made from these materials.
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Affiliation(s)
- Philipp Kohorst
- Department of Prosthetic Dentistry and Biomedical Materials Science, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
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12
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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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Oyar P, Soyarslan C, Can G, Demirci E. Finite element analysis of stress distribution on modified retentive tips of bar clasp. Comput Methods Biomech Biomed Engin 2011; 15:609-13. [PMID: 21347911 DOI: 10.1080/10255842.2011.554406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This study used finite element analysis to evaluate the retentive tips of bar clasps made from different alloys and using different designs in order to determine whether or not different materials and tip forms are suitable for bar clasp applications. Co-Cr, Ti and Type IV Au alloys were selected based on their physical and mechanical properties. The 3D finite element models of three different bar clasp retentive tip geometries prepared from Co-Cr, Ti and Type IV Au alloys were constructed using the finite element software package MSC.Marc. Analysis of a concentrated load of 5 N applied to the removable partial denture approach arms in an occlusal direction was performed. Although stress distribution and localisation within bar clasps with different retentive tips were observed to be similar and were concentrated in the approach arm, stress intensities differed in all models.
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Affiliation(s)
- P Oyar
- School of Dental Technology, Hacettepe University, Ankara, Turkey.
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14
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Kibi M, Ono T, Dong J, Mitta K, Gonda T, Maeda Y. Development of an RPD CAD system with finite element stress analysis. J Oral Rehabil 2010; 36:442-50. [PMID: 19554664 DOI: 10.1111/j.1365-2842.2009.01949.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The structural design of removable partial dentures (RPDs) is critical for preventing distortion of the prosthesis, protecting abutment teeth and residual ridges as well as for high masticatory performance. The aim of this study was to clarify the feasibility and utility of a computer-aided designing (CAD) system with finite element analysis (FEA) for molar teeth arrangement in unilateral distal extension base RPDs. The shapes of artificial teeth and residual ridge were measured and converted into point group data. Solid models were created from surface-modelled point group data in a 3D surface CAD format. An occlusal rim was created on the residual ridge mucosa and the occlusal rim - residual ridge mucosa model with FEA function was created. Stress distribution on the residual ridge mucosa was compared by changing the loading point. The artificial teeth were then arranged in locations with the lowest amount of stress. After building an artificial teeth - saddle - residual ridge mucosa model, stress distribution in the residual ridge mucosa was re-evaluated by simulating occlusal force. On the occlusal rim - residual ridge mucosa model, stress was reduced when the loading point was located around the buccal shelf where functional cusps of artificial teeth were charted. It was confirmed that stress distribution in the residual ridge mucosa was equalized on the artificial teeth - saddle - residual ridge mucosa model. This system might be clinically useful tool for designing RPDs if FEA-guided designing of retainers and connectors can be added.
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Affiliation(s)
- M Kibi
- Kibi Dental Clinic, Toyonaka, Japan
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