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Peng PW, Chen MS, Peng TY, Huang PC, Nikawa H, Lee WF. In vitro study of optimal removable partial denture clasp design made from novel high-performance polyetherketoneketone. J Prosthodont Res 2024; 68:466-473. [PMID: 38220161 DOI: 10.2186/jpr.jpr_d_23_00080] [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] [Indexed: 01/16/2024]
Abstract
PURPOSE This study aimed to investigate the retentive force and deformation of double Akers' polyetherketoneketone (PEKK) clasps on removable partial dentures (RPDs) with varying designs and undercut depths. METHODS Thirty double Akers' PEKK clasps with two different widths and heights (Groups I and II) were fabricated using computer-aided design and computer-aided manufacturing (CAD/CAM). Each design was further subdivided (n = 5) into three undercut depths (0.25, 0.50, and 0.75 mm). The retentive force of the clasps was measured after 10 years of clinical use (15,000 insertion/removal cycles), and the deformation of the clasp tips was analyzed before and after cycling. RESULTS Clasps with 0.50-mm and 0.75-mm undercut depths exhibited greater initial retentive forces (3.15-3.51 N) compared to those in the 0.25-mm undercut group (2.40-2.80 N). Group I maintained consistent retentive forces over the cycles (P = 0.345), whereas Group II showed declining forces after the initial use (P < 0.003). In both groups, the 0.50-mm undercut exhibited a greater retentive force than the 0.25-mm (P < 0.001 and P < 0.004, respectively), with no significant differences between the 0.50-mm and 0.75-mm undercut depths. Despite a lower initial retentive force, the 0.25-mm undercut showed less deformation and clasp tip wear. CONCLUSIONS The PEKK clasps did not exhibit significantly reduced retentive forces or permanent deformations after 15,000 fatigue cycles. These results suggest that the PEKK polymer displays superior mechanical properties as an esthetic clasp material, and clasps with 0.50-mm and 0.75-mm undercut depths are recommended for long-term clinical use.
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Affiliation(s)
- Pei-Wen Peng
- School of Dental Technology, Taipei Medical University, Taipei, Taiwan
| | - May-Show Chen
- School of Dentistry, Taipei Medical University, Taipei, Taiwan
- Division of Prosthodontics, Department of Dentistry, Taipei Medical University Hospital, Taipei, Taiwan
| | - Tzu-Yu Peng
- School of Dentistry, Taipei Medical University, Taipei, Taiwan
| | - Peng-Chien Huang
- School of Dental Technology, Taipei Medical University, Taipei, Taiwan
| | - Hiroki Nikawa
- Department of Oral Biology & Engineering, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima City, Hiroshima, Japan
| | - Wei-Fang Lee
- School of Dental Technology, Taipei Medical University, Taipei, Taiwan
- School of Dentistry, Taipei Medical University, Taipei, Taiwan
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Luo Y, Qiu L, Geng M, Zhang W. Retention and fatigue performance of modified polyetheretherketone clasps for removable prosthesis. J Mech Behav Biomed Mater 2024; 154:106539. [PMID: 38598917 DOI: 10.1016/j.jmbbm.2024.106539] [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: 01/18/2024] [Revised: 04/01/2024] [Accepted: 04/03/2024] [Indexed: 04/12/2024]
Abstract
PURPOSE Polyetheretherketone (PEEK) is considered as an alternative to metal material for removable partial denture (RPD). However, the retentive force is not strong as a metal RPD. This study investigated the retention and fatigue performance of PEEK clasps with different proportions of clasp arm engaging the undercut to verify a new strategy to improve their clinical performance. METHODS Three groups (n = 10/group) of PEEK clasps with their terminal 1/3, 2/3 and the whole of retentive arms engaging the undercut were fabricated along with a group (n = 10) of conventional cobalt-chrome (CoCr) clasps as control group. Retentive forces were measured by universal testing machine initially and at an interval of 1500 cycles for a total of 15,000 fatigue cycles. The fatigue cycles were conducted by repeated insertion and removal of the clasp using fatigue testing machine. Each clasp was scanned by Trios3 scanner before and after fatigue test to obtain digital models. The deformation of the clasp was evaluated by root mean square (RMS) through aligning the two models in Geomagic wrap (2021). Scanning electron microscopy (SEM) and finite element analysis were carried out to observe the abrasion and the von Mises stress of the clasp arm. Kruskal-Wallis H test was used to compare the retentive forces and the RMSs of the studied groups followed by Bonferroni multiple comparisons. RESULTS The whole of PEEK clasp arm engaging the undercut provided higher mean retentive forces (7.99 ± 2.02 N) than other PEEK clasp groups (P < 0.001) and was closer to CoCr clasps (11.88 ± 2.05 N). The RMSs of PEEK clasps were lower than CoCr clasps (P < 0.05) while the differences among PEEK clasps were of no statistical significance (P > 0.05). SEM showed that evidences of surface abrasion were observed on the section that engaged the undercut for all groups of clasps. The stress concentration mainly occurred on the initial part of the retentive arm. The maximum von Mises stress of each group was below the compressive strength of PEEK. CONCLUSIONS Proportions of PEEK clasp arm engaging the undercut positively influenced the retentive force and the fatigue resistance of PEEK clasps was superior than CoCr clasps. It is a feasible method to improve the retention of PEEK clasps by increasing the proportion of clasp arm engaging the undercut. Clinical trials are needed to further verify this innovation.
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Affiliation(s)
- Yichen Luo
- Department of Oral Special Consultation, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, PR China; State Key Laboratory Cultivation Base of Research, Prevention and Treatment for Oral Diseases (Nanjing Medical University), Nanjing, PR China; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, PR China
| | - Lin Qiu
- Department of Oral Special Consultation, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, PR China; State Key Laboratory Cultivation Base of Research, Prevention and Treatment for Oral Diseases (Nanjing Medical University), Nanjing, PR China; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, PR China
| | - Mingzhu Geng
- Department of Oral Special Consultation, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, PR China; State Key Laboratory Cultivation Base of Research, Prevention and Treatment for Oral Diseases (Nanjing Medical University), Nanjing, PR China; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, PR China
| | - Wei Zhang
- Department of Oral Special Consultation, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, PR China; State Key Laboratory Cultivation Base of Research, Prevention and Treatment for Oral Diseases (Nanjing Medical University), Nanjing, PR China; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, PR China.
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Lee WF, Chen MS, Peng TY, Huang PC, Nikawa H, Peng PW. Comparative analysis of the retention force and deformation of PEEK and PEKK removable partial denture clasps with different thicknesses and undercut depths. J Prosthet Dent 2024; 131:291.e1-291.e9. [PMID: 38057199 DOI: 10.1016/j.prosdent.2023.09.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 09/27/2023] [Accepted: 09/27/2023] [Indexed: 12/08/2023]
Abstract
STATEMENT OF PROBLEM The retentive force and deformation of milled polyetheretherketone (PEEK) and polyetherketoneketone (PEKK) removable partial denture (RPD) frameworks are not well understood. PURPOSE The purpose of this in vitro study was to assess the retentive force and deformation of PEEK and PEKK Akers clasps with different designs and undercut depths. MATERIAL AND METHODS A master model containing the first and second molar abutments was used to design Akers clasps of different cross-sectional dimensions, undercut depths (0.5 and 0.75 mm), and materials. The components of the removable partial denture framework also included an occlusal rest and were manufactured using a milling machine (n=5). The fatigue resistance of the Akers clasps was measured before and after deformation regarding the retentive forces. RESULTS The PEEK2-U50 clasp had the largest retentive force with no significant difference among all groups before and after the insertion and removal cycle. In addition, the increased cross-sectional dimensions of the design resulted in significant differences in retentive forces between the PEEK1 and PEEK2 groups and between the PEEK and PEKK materials. CONCLUSIONS Increasing the clasp's cross-sectional dimensions significantly impacted retentive forces, especially between different PEEK groups and between PEEK and PEKK materials.
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Affiliation(s)
- Wei-Fang Lee
- Associate Professor, School of Dental Technology, Taipei Medical University, Taipei, Taiwan, ROC; and PhD student, School of Dentistry, Taipei Medical University, Taipei, Taiwan, ROC
| | - May-Show Chen
- Associate Professor, School of Dentistry, Taipei Medical University, Taipei, Taiwan, ROC; and Visiting Doctor, Division of Prosthodontics, Department of Dentistry, Taipei Medical University Hospital, Taipei, Taiwan, ROC
| | - Tzu-Yu Peng
- Assistant Professor, School of Dentistry, Taipei Medical University, Taipei, Taiwan, ROC
| | - Peng-Chien Huang
- Dental Technician, School of Dental Technology, Taipei Medical University, Taipei, Taiwan, ROC
| | - Hiroki Nikawa
- Professor, Department of Oral Biology & Engineering, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima City, Hiroshima, Japan
| | - Pei-Wen Peng
- Professor, School of Dental Technology, Taipei Medical University, Taipei, Taiwan, ROC.
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Retentive design of a small surgical guide for implant surgery: An in-vitro study. J Dent 2023; 128:104384. [PMID: 36470471 DOI: 10.1016/j.jdent.2022.104384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 10/17/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVES Instability of the surgical guide is an overlooked factor that can result in a difference between the planned and the actual positions of an implant. Our aim was to compare the stability of the retentive surgical guide (RSG) with a conventional surgical guide (CSG) in an in-vitro experiment. METHODS A platform to evaluate the stability of the surgical guide was designed using 3D-modelling software (Meshmixer 3.5, Autodesk). Imaging data from 15 patients with a single missing tooth were used to plan the virtual implant. Two surgical guides were designed (Blue Sky Plan 4.8, Blue Sky Bio) and 3D printed (Form2, Dental SG resin, Formlabs) for each case: the CSG with the default, predetermined software settings, and the RSG, designed on a dental model with a 0.1-mm undercut and altered production parameters (reduced guide-to-teeth offset of 0.07 mm, reduced guide thickness of 2.3 mm and a retentive clasp in a marginal area). The dental models were reproducibly secured on the testing platform using a digital force gauge, and the surgical guides were positioned. An increasing force of 0.1 N, 1 N, 2.5 N, and 5 N was sequentially applied from the buccal and the oral directions to the surgical guide via a drill handle. For each force, either the magnitude of the guide's displacement was captured with an intra-oral scanner (CEREC Omnicam AC, Dentsply Sirona; software version: SW 4.5.2) or the dislodgement of the guide was recorded. Scans were imported for analysis (GOM Inspect 2018, GOM GmbH), and library files of the surgical guides and implants were superimposed as a joined complex. The deviation of the implant's position was calculated from the displacement of the guide's position RESULTS: Three-way repeated measures using ANOVA revealed a more significant guide displacement and virtually projected implant deviation in the CSG group than the RSG group and with increasing force in all the deviation parameters. Both groups showed greater resistance to the displacement with the force applied from the oral direction than the buccal direction. The application of the force in the buccal direction resulted in guide dislodgements of 13% and 0% for the CSG and RSG, respectively. In the oral direction, the dislodgement rates were 33% and 7% for the CSG and RSG, respectively. CONCLUSIONS Within the limitations of this study, the retentive design increased the stability of the surgical guide and, consequently, the accuracy of the virtually projected implants in comparison to the conventional surgical guide designed using the default settings. Clinical trials are needed to confirm its advantages in clinical use. CLINICAL SIGNIFICANCE With a simple modification to the design, the surgical guide retention provided greater stability, with smaller deviations under loading; this resulted in improved implant precision parameters without requiring additional materials or software. Further studies are needed to assess the clinical feasibility of this surgical guide with improved retention and function.
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Performance of Graphene-Based and Polyether-Ether-Ketone Polymers as Removable Partial Denture Esthetic Clasp Materials after Cyclic Fatigue. Polymers (Basel) 2022; 14:polym14152987. [PMID: 35893952 PMCID: PMC9331630 DOI: 10.3390/polym14152987] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 11/17/2022] Open
Abstract
The esthetic clasp material is a clinical demand for a satisfactory removable partial denture. The purpose of this study is to assess the mechanical performance of graphene-based polymer (GBP) and polyether-ether-ketone (PEEK) materials as clasp materials. Thirty-two clasps were fabricated by CAD-CAM from two materials, GBP and PEEK. All clasps were tested for retention force after 10,000 cycles of insertion and removal and thermocycling. The clasp arms’ deformation was measured, and areas of stress−strain concentration were explored. The Mann−Whitney U test was used to compare the retentive force of the studied groups, while the independent sample t-test was applied to check the difference in clasp arm deformation at α = 0.5. The results showed a significantly higher retentive force (2.248 ± 0.315 N) in PEEK clasps, at p < 0.001. The deformation of the clasp arm of the GBP clasps was significantly higher than PEEK clasps. Areas of stress−strain concentration were seen at the junction of the retentive arm to the minor connector and at the retentive arm terminal. It could be concluded that PEEK polymer had a better mechanical performance as an esthetic clasp material than the GBP. An optimization study for GBP might be required to check the validity of such an application.
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Takakusaki K, Murakami N, Wada J, Kasai T, Matsuno H, Yamazaki T, Iwasaki N, Yatabe M, Takahashi H, Wakabayashi N. Effect of retention hole designs in artificial teeth on failure resistance of the connection with thermoplastic resin. Dent Mater J 2022; 41:573-579. [PMID: 35418549 DOI: 10.4012/dmj.2021-328] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
This study aimed to evaluate the effect of retention hole designs in artificial teeth on failure resistance of the connection with a thermoplastic denture base resin. Artificial teeth with the following retention hole designs were attached to polyester and polyamide resins: no hole, vertical hole, horizontal hole, and vertical and horizontal holes. An artificial tooth with no hole attached to polymethyl methacrylate was prepared as the control. The load was applied until connection failure occurred between the artificial tooth and resin, and failure resistance was detected. Although the control showed the highest resistance, the artificial tooth with vertical and horizontal holes showed higher resistance than those with other retention hole designs in both thermoplastic resins. Providing vertical and horizontal retention holes in artificial teeth may be effective in improving failure resistance of the connection with thermoplastic resins.
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Affiliation(s)
- Kensuke Takakusaki
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Natsuko Murakami
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Junichiro Wada
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Taihei Kasai
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Hitomi Matsuno
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Toshiki Yamazaki
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Naohiko Iwasaki
- Oral Biomaterial Development Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Masaru Yatabe
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Hidekazu Takahashi
- Oral Biomaterial Development Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Noriyuki Wakabayashi
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
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Biomechanics in Removable Partial Dentures: A Literature Review of FEA-Based Studies. BIOMED RESEARCH INTERNATIONAL 2021; 2021:5699962. [PMID: 34485518 PMCID: PMC8416386 DOI: 10.1155/2021/5699962] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/23/2021] [Accepted: 07/30/2021] [Indexed: 12/12/2022]
Abstract
The present study was aimed at reviewing the studies that used finite element analysis (FEA) to estimate the biomechanical stress arising in removable partial dentures (RPDs) and how to optimize it. A literature survey was conducted for the English full-text articles, which used only FEA to estimate the stress developed in RPDs from Jan 2000 to May 2021. In RPDs, the retaining and supporting structures are subjected to dynamic loads during insertion and removal of the prosthesis as well as during function. The majority of stresses in free-end saddle (FES) RPDs are concentrated in the shoulder of the clasp, the horizontal curvature of the gingival approaching clasp, and the part of the major connector next to terminal abutments. Clasps fabricated from flexible materials were beneficial to eliminate the stress in the abutment, while rigid materials were preferred for major connectors to eliminate the displacement of the prosthesis. In implant-assisted RPD, the implant receive the majority of the load, thereby reducing the stress on the abutment and reducing the displacement of the prosthesis. The amount of stress in the implant decreases with zero or minimal angulation, using long and wide implants, and when the implants are placed in the first molar area.
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Hao J, Murakami N, Yamazaki T, Iwasaki N, Yatabe M, Takahashi H, Wakabayashi N. Flexural and fatigue properties of polyester disk material for milled resin clasps. Dent Mater J 2021; 40:1359-1364. [PMID: 34234049 DOI: 10.4012/dmj.2021-037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
To evaluate the flexural and fatigue properties of a polyester disk material used in milled resin clasps of removable partial dentures, experimental polyester disk (mPE), injection-molded polyester (iPE), and polymethyl methacrylate disk (mPMMA) were examined by three-point bending tests and cyclic fatigue tests at 0.75 or 1.50 mm deflection. The mPE exhibited significantly higher flexural strength than the iPE (p<0.05). Meanwhile, the mPMMA displayed higher flexural modulus and strength than the polyesters. The mPE exhibited a significantly lower residual strain than the iPE at the cyclic 0.75 mm deflection (p<0.05); however, microcracks were observed in the mPE at the 1.50 mm deflection. The mPMMA showed a high residual strain at the 0.75 mm deflection and fractured within 1,000 cycles at the 1.5 mm deflection. The higher flexural strength and lower residual strain of the mPE compared with the iPE suggest the advantages of milled resin clasps within a limited deflection.
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Affiliation(s)
- Jialin Hao
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Natsuko Murakami
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Toshiki Yamazaki
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Naohiko Iwasaki
- Oral Biomaterial Development Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Masaru Yatabe
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Hidekazu Takahashi
- Oral Biomaterial Development Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Noriyuki Wakabayashi
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
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Kumar N, Koli DK, Jain V, Nanda A. Stress distribution and patient satisfaction in flexible and cast metal removable partial dentures: Finite element analysis and randomized pilot study. J Oral Biol Craniofac Res 2021; 11:478-485. [PMID: 34345583 DOI: 10.1016/j.jobcr.2021.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 05/11/2021] [Accepted: 06/27/2021] [Indexed: 10/20/2022] Open
Abstract
Purpose To compare stress distribution in polyacetyl based flexible RPD (FRPD) with cast metal RPD (CRPD) by using three-dimensional finite element analysis (FEA) and patient satisfaction by using OHIP-14 questionnaire in participants with Kennedy's class I partially edentulous mandibular arch rehabilitated with CRPD and FRPD. Material and methods For FEA, 3D models of Kennedy's class I partially edentulous mandibular arch, CRPD in chrome-cobolt alloy, and polyacetyl based FRPD were geometrically modelled and subjected to a vertical load of 100 N bilaterally. The in vivo comparison of satisfaction was assessed by enrolling 22 participants with Kennedy's class I partially edentulous mandibular arch. After randomization, 11 participants were rehabilitated by CRPD (group C), and 11 participants by polyacetyl based FRPD (group F). OHIP-14 questionnaire in Hindi language was filled at 1 week and 1 year after denture insertion. Results Von Mises stress distribution in CRPD was maximum in mesial rest seat of the primary abutment (100 MPa) and minimum for edentulous ridge (7 MPa on bone and 6 MPa on mucosa). Von Mises stress distribution for polyaccetyl based FRPD was maximum in ridge (25 MPa) and minimum in periodontal ligament of the second premolar (3 MPa). Patient satisfaction in group F was significantly more than in group C at end of 1 year (P = .0158). Conclusion FRPD is useful in periodontally compromised abutment teeth and CRPD in resorbed ridge conditions. Patient satisfaction is more with polyacetyl based flexible RPD when compared with cast metal RPD at the end of 1 year.
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Affiliation(s)
- Niraj Kumar
- Department of Prosthodontics, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Dheeraj Kumar Koli
- Department of Prosthodontics, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Veena Jain
- Department of Prosthodontics, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Aditi Nanda
- Department of Prosthodontics, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, 110029, India
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Gentz FI, Brooks DI, Liacouras PC, Petrich A, Hamlin CM, Ellert DO, Ye L. Retentive Forces of Removable Partial Denture Clasp Assemblies Made from Polyaryletherketone and Cobalt-Chromium: A Comparative Study. J Prosthodont 2021; 31:299-304. [PMID: 34081360 DOI: 10.1111/jopr.13398] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2021] [Indexed: 11/28/2022] Open
Abstract
PURPOSE To compare retentive forces of removable partial denture clasps traditionally fabricated with cobalt-chromium (CoCr) material and two computer-aided design and computer-aided manufactured (CAD/CAM) thermoplastic polymers. MATERIALS AND METHODS Forty-eight clasp assemblies (16 CoCr, 16 polyetheretherketone (PEEK) and 16 polyetherketoneketone (PEKK) thermoplastic polymer) were fabricated for 48 mandibular tooth analogs. Individual clasps were inserted and removed on the tooth analogs utilizing a chewing simulator for 15,000 cycles to simulate 10 years of use. Retentive forces were measured utilizing a mechanical load tester at baseline and intervals of 1500 cycles. Data were analyzed with one-way Analysis of Variance, Tukey post-hoc, and paired T tests. RESULTS Mean retentive forces between all groups were significantly different (p < 0.001). Retentive forces of CoCr clasps were significantly higher than both polymers (p < 0.001). The mean retentive forces for PEEK were not significantly different from PEKK (p = 0.23). A significant increase in retentive forces was observed for all three clasps after the first period of cycling, followed by continual decrease for the remaining cycles. At the endpoint of 15,000 cycles, no clasp assemblies showed lower retentive forces than at initial baseline. CONCLUSION Thermoplastic polymer clasps demonstrated lower retentive forces compared to CoCr clasps. All three groups displayed a similar pattern of initial increase, followed by a gradual decrease, of retentive force. Despite this observation, the clasps maintained similar or higher retentive forces than measured at baseline. This resistance to fatigue and ability to fabricate with CAD/CAM technologies provides support for clinical use of these high-performance polymer (HPP) materials.
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Affiliation(s)
- Frank I Gentz
- Prosthodontics Department, Naval Postgraduate Dental School, Naval Medical Leader & Professional Development Command; Postgraduate Dental College, Uniformed Services University of Health Sciences, Bethesda, MD
| | - Daniel I Brooks
- Department of Research Programs, Walter Reed National Military Medical Center, Bethesda, MD
| | - Peter C Liacouras
- 3D Medical Applications Center, Department of Radiology, Walter Reed National Military Medical Center, Bethesda, MD.,Naval Postgraduate Dental School, Bethesda, MD
| | - Anton Petrich
- Prosthodontics Department, Naval Postgraduate Dental School, Naval Medical Leader & Professional Development Command; Postgraduate Dental College, Uniformed Services University of Health Sciences, Bethesda, MD
| | - Christopher M Hamlin
- Prosthodontics Department, Naval Postgraduate Dental School, Naval Medical Leader & Professional Development Command; Postgraduate Dental College, Uniformed Services University of Health Sciences, Bethesda, MD
| | - Daniel O Ellert
- Prosthodontics Department, Naval Postgraduate Dental School, Naval Medical Leader & Professional Development Command; Postgraduate Dental College, Uniformed Services University of Health Sciences, Bethesda, MD
| | - Ling Ye
- Research Department, Naval Postgraduate Dental School, Naval Medical Leader & Professional Development Command; Postgraduate Dental College, Uniformed Services University of Health Sciences, Bethesda, MD
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Tashiro S, Kawaguchi T, Hamanaka I, Takahashi Y. Bond strength of artificial teeth to thermoplastic denture base resin for injection molding. Dent Mater J 2021; 40:657-663. [PMID: 33456030 DOI: 10.4012/dmj.2020-183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This research was conducted to investigate the bond strength between artificial teeth and a thermoplastic denture base resin for injection molding with different surface preparations for use in flexible resin removable partial dentures. Composite resin denture teeth and acrylic denture resin teeth were bonded to three types of thermoplastic denture base resins for injection molding (polyamide, polyester, and polycarbonate) and a conventional heat-polymerized polymethyl methacrylate (PMMA) resin (control). The ridge lap surfaces of the artificial teeth were classified into four groups based on the type of ridge lap surface treatment applied (n=10): no treatment, ethyl acetate, small T-shaped tunnel, and large T-shaped tunnel. The specimens were tested for bond strength. The results showed that the ethyl acetate treatment was ineffective for enhancing the bond strength (p>0.05) between the artificial teeth and thermoplastic denture base resin for injection molding, whereas the T-shaped tunnel was quite effective in this regard (p<0.05).
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Affiliation(s)
- Shu Tashiro
- Division of Removable Prosthodontics, Department of Oral Rehabilitation, Fukuoka Dental College
| | - Tomohiro Kawaguchi
- Division of Removable Prosthodontics, Department of Oral Rehabilitation, Fukuoka Dental College
| | - Ippei Hamanaka
- Division of Removable Prosthodontics, Department of Oral Rehabilitation, Fukuoka Dental College
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Retention force of polyetheretherketone and cobalt-chrome-molybdenum removable dental prosthesis clasps after artificial aging. Clin Oral Investig 2020; 25:3141-3149. [PMID: 33064206 PMCID: PMC8060199 DOI: 10.1007/s00784-020-03642-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 10/09/2020] [Indexed: 12/26/2022]
Abstract
OBJECTIVES To examine the retention force of removable dental prosthesis (RDP) clasps made from polyetheretherketone (PEEK) and cobalt-chrome-molybdenum (CoCrMo, control group) after storage in water and artificial aging. MATERIALS AND METHODS For each material, 15 Bonwill clasps with retentive buccal and reciprocal lingual arms situated between the second pre- and first molar were manufactured by milling (Dentokeep [PEEKmilled1], NT digital implant technology; breCAM BioHPP Blank [PEEKmilled2], bredent), pressing (BioHPP Granulat for 2 press [PEEKpressed], bredent), or casting (remanium GM 800+ [CoCrMo], Dentaurum); N = 60, n = 15/subgroup. A total of 50 retention force measurements were performed for each specimen per aging level (initial; after storage [30 days, 37 °C] and 10,000 thermal cycles; after storage [60 days, 37 °C] and 20,000 thermal cycles) in a pull-off test. Data were statistically analyzed using one-way ANOVA, post hoc Scheffé and mixed models (p < 0.05). RESULTS Initial, PEEKpressed (80.2 ± 35.2) and PEEKmilled1 (98.9 ± 40.3) presented the lowest results, while PEEKmilled2 (170.2 ± 51.8) showed the highest values. After artificial aging, the highest retention force was observed for the control group (131.4 ± 56.8). The influence of artificial aging was significantly higher for PEEK-based materials. While PEEKmilled2 and PEEKpressed showed an initial decline in retention force, all other groups presented no impact or an increase in retention force over a repetitive insertion and removal of the clasps. CONCLUSIONS Within the tested PEEK materials, PEEKmilled2 presented superior results than PEEKpressed. Although CoCrMo showed higher values after artificial aging, all materials exhibited sufficient retention to recommend usage under clinical conditions. CLINICAL RELEVANCE As RDPs are still employed for a wide range of indications, esthetic alternatives to conventional CoCrMo clasps are sought.
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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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Tribst JPM, Dal Piva AMDO, Borges ALS, Araújo RM, da Silva JMF, Bottino MA, Kleverlaan CJ, de Jager N. Effect of different materials and undercut on the removal force and stress distribution in circumferential clasps during direct retainer action in removable partial dentures. Dent Mater 2019; 36:179-186. [PMID: 31791736 DOI: 10.1016/j.dental.2019.11.022] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 10/22/2019] [Accepted: 11/15/2019] [Indexed: 11/16/2022]
Abstract
OBJECTIVES This study aimed to evaluate the effect of different materials and undercut on the removal force and stress distribution in the supporting tooth and in the circumferential clasp used in removable partial prosthesis. METHODS Upper molars prepared for Akers circumferential clasp with retention and opposing arm were modeled, scanned, elaborated with CAD software and the geometries imported in FEA and analyzed. Six different materials were selected for the clasp (Polyamide, Polyoxymethylene, Polyetheretherketone - PEEK, Gold alloy, Titanium and CoCr) and 3 different undercuts (0.25, 0.50 and 0.75mm), totaling 18 groups. RESULTS The clasps presented greater stress in their structure and potentially greater damage to the dental enamel when made with rigid materials and with more undercut; however, they presented greater ability to remain in position. SIGNIFICANCE Polyamide with a higher undercut is an esthetic alternative to rigid metallic clasps. It showed promising behavior because it strongly reduces the damage to the enamel, and even with an undercut of 0.75, the retention is lower than for CoCr with a 0.25 undercut, and this retention might still be sufficient. Polyoxymethylene and Polyetheretherketone (PEEK) are not suitable materials for the clasps, because the maximum stress occurring during removal with higher undercuts is higher than the material strength.
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Affiliation(s)
- João Paulo Mendes Tribst
- PhD Graduate Program in Restorative Dentistry, São Paulo State University (Unesp), Institute of Science and Technology, Av. Eng. Francisco José Longo, nº 777. Jardim São Dimas, 12245-000, São José dos Campos, SP, Brazil; Department of Dental Materials Science, Academic Center for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Gustav Mahlerlaan #3004, 1081 LA, Amsterdam, Noord-Holland, The Netherlands.
| | - Amanda Maria de Oliveira Dal Piva
- PhD Graduate Program in Restorative Dentistry, São Paulo State University (Unesp), Institute of Science and Technology, Av. Eng. Francisco José Longo, nº 777. Jardim São Dimas, 12245-000, São José dos Campos, SP, Brazil; Department of Dental Materials Science, Academic Center for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Gustav Mahlerlaan #3004, 1081 LA, Amsterdam, Noord-Holland, The Netherlands.
| | - Alexandre Luiz Souto Borges
- PhD Graduate Program in Restorative Dentistry, São Paulo State University (Unesp), Institute of Science and Technology, Av. Eng. Francisco José Longo, nº 777. Jardim São Dimas, 12245-000, São José dos Campos, SP, Brazil.
| | - Rodrigo Máximo Araújo
- PhD Graduate Program in Restorative Dentistry, São Paulo State University (Unesp), Institute of Science and Technology, Av. Eng. Francisco José Longo, nº 777. Jardim São Dimas, 12245-000, São José dos Campos, SP, Brazil.
| | - João Maurício Ferraz da Silva
- PhD Graduate Program in Restorative Dentistry, São Paulo State University (Unesp), Institute of Science and Technology, Av. Eng. Francisco José Longo, nº 777. Jardim São Dimas, 12245-000, São José dos Campos, SP, Brazil.
| | - Marco Antonio Bottino
- PhD Graduate Program in Restorative Dentistry, São Paulo State University (Unesp), Institute of Science and Technology, Av. Eng. Francisco José Longo, nº 777. Jardim São Dimas, 12245-000, São José dos Campos, SP, Brazil.
| | - Cornelis Johannes Kleverlaan
- Department of Dental Materials Science, Academic Center for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Gustav Mahlerlaan #3004, 1081 LA, Amsterdam, Noord-Holland, The Netherlands.
| | - Niek de Jager
- Department of Dental Materials Science, Academic Center for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Gustav Mahlerlaan #3004, 1081 LA, Amsterdam, Noord-Holland, The Netherlands.
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