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Tonin BSH, Peixoto RF, Fu J, Freitas BND, Mattos MDGCD, Macedo AP. Evaluation of misfit and stress distribution in implant-retained prosthesis obtained by different methods. Braz Dent J 2021; 32:67-76. [PMID: 34877979 DOI: 10.1590/0103-6440202104453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 09/13/2021] [Indexed: 11/22/2022] Open
Abstract
This study evaluated the vertical misfit, passivity, and stress distribution after tightening the screws of different prosthesis. Two implants were used to simulate the rehabilitation of partially edentulous mandible space from the second premolar to the second molar. 40 three-element screw-retained fixed dental prosthesis with distal cantilever were fabricated and divided into four groups according to the method of production of framework (n = 10): G1 = conventional casting one-piece framework, G2 = conventional casting sectioned and laser welding, G3 = conventional casting sectioned and tungsten inert gas (TIG) welding and G4 = framework obtained by CAD/CAM (computer-aided design/computer-aided manufacturing) system. The vertical misfits (both screws tightened) and the passive fit (one screw tightened) were measured under a comparator optical microscope. The data was submitted to Shapiro-Wilk test to enable comparison with ANOVA followed by Tukey with Bonferroni adjust (α = .05). The qualitative analysis of the stress distribution was performed by the photoelastic method. The vertical misfit (both screws tightened) of the G2 (24 μm) and G3 (27 μm) were significantly higher than G4 (10 μm) (p = 0,006). The passive fit (for the non-tightened) of the G1(64 μm) and G3 (61 μm) were significantly higher than the G4 (32 μm) (p=0,009). G1 showed high stress between the implants in the photoelastic analysis and G4 presented lower stress. In conclusion, CAD/CAM method results in less vertical misfit, more passivity, and consequently better stress distribution to the bone.
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Affiliation(s)
- Bruna Santos Honório Tonin
- Department of Dental Materials and Prosthesis, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Raniel Fernandes Peixoto
- Department of Restorative Dentistry, Faculty of Pharmacy, Dentistry and Nursing, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Jing Fu
- Department of Prosthodontics the Affiliated Hospital of QingdaoUniversity, School of Dentistry, Qindao, China
| | - Bruna Neves de Freitas
- Department of Dental Materials and Prosthesis, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | | | - Ana Paula Macedo
- Department of Dental Materials and Prosthesis, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
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Gomes JMDL, Moraes SLDD, Lemos CAA, Cruz RS, Oliveira HFFE, Pellizzer EP. Systematic review and meta-analysis of welding procedures in one-piece cast implant-supported frameworks. Braz Oral Res 2019; 33:e110. [PMID: 31778474 DOI: 10.1590/1807-3107bor-2019.vol33.0110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 10/10/2019] [Indexed: 11/21/2022] Open
Abstract
The objective of this systematic review and meta-analysis was to evaluate the effect of welding techniques on implant-supported prostheses and determine whether they contribute to a better adaptation compared with a one-piece cast. A search was conducted using the PubMed/MEDLINE, Embase, and Cochrane Library databases, and articles published until November 2017 were obtained from these databases. This review followed the PRISMA criteria and is registered on the PROSPERO platform (CRD42017081865). The PICO question was "Do welding procedures in one-piece cast implant-supported frameworks influence implant/abutment-framework marginal misfits?" Eleven studies were selected for a qualitative analysis, and seven studies were selected for a quantitative analysis. A total of 189 specimens were fabricated using different materials (cp-Ti, Ni-Cr, Cr-Co, and noble alloys), and welding techniques such as laser welding, conventional welding, tungsten inert gas, and brazing were applied. A vertical marginal misfit was measured using an optical microscope, a stereomicroscope, and/or a scanning electron microscopy. The qualitative analysis in the studies demonstrated a positive effect of the welding techniques on the adaptation of the infrastructures. The meta-analysis confirmed the results (p < 0.00001; MD: -36.14; 95%CI: -48.69 to -23.59). Within the limitations of this study and regarding the heterogeneity of the samples, we conclude that the soldering point technique is effective for obtaining relatively low values of marginal misfit, with laser welding as the most effective technique. However, additional studies were recommended due to the heterogeneity of different variables (alloys, connection, and misfit evaluation) in the included studies.
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Affiliation(s)
- Jéssica Marcela de Luna Gomes
- Universidade Estadual Paulista - Unesp, Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba, SP, Brazil
| | | | - Cleidiel Aparecido Araujo Lemos
- Universidade Estadual Paulista - Unesp, Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba, SP, Brazil
| | - Ronaldo Silva Cruz
- Universidade Estadual Paulista - Unesp, Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba, SP, Brazil
| | | | - Eduardo Piza Pellizzer
- Universidade Estadual Paulista - Unesp, Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba, SP, Brazil
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Evaluation of Marginal Misfit of Metal Frameworks Welded by Gas-Torch, Laser, and Tungsten Inert Gas Methods. Int J Dent 2018; 2018:9828929. [PMID: 30510577 PMCID: PMC6232793 DOI: 10.1155/2018/9828929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/30/2018] [Accepted: 09/18/2018] [Indexed: 12/02/2022] Open
Abstract
Purpose The objective of this study was to evaluate the marginal fit and the flexural resistance of nickel-chromium frameworks welded by different techniques, gas-torch, laser, and tungsten inert gas (TIG), compared with that of frameworks made via one-piece casting. Methods To evaluate the marginal fit, a master model was fabricated simulating four implants. Transfers and replicas were used to transfer the positions of the implants to the model, using a silicone matrix. The bars were waxed up and casted. Three assessments of misfit were performed for each implant using a stereomicroscope before and after welding in two predetermined regions, totaling six readings for each implant. To evaluate the flexural resistance, one group was made casting the specimens in one piece. Other 3 groups using gas-torch, laser, and TIG welding techniques were made after sectioned transversally. The data showed normal distribution and two-way ANOVA for marginal fit and one-way ANOVA for flexural resistance, and Tukey's posttest (α=0.05) was performed. Results For the marginal fit, the three welding methods presented similar results and were different from one-piece casting. For the flexural resistance, significant differences were observed among the studied groups (p < 0.001), and the one-piece group presented higher resistance compared to the three welding techniques. Conclusions Within the limits of this study, the three welding techniques yielded similar misfit results, and the laser and TIG techniques presented similar flexural resistance but lower than gas-torch and one-piece casting.
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Singh I, Nair KC, Shetty J. Effect of joining the sectioned implant-supported prosthesis on the peri-implant strain generated in simulated mandibular model. J Indian Prosthodont Soc 2017; 17:388-394. [PMID: 29249883 PMCID: PMC5730916 DOI: 10.4103/jips.jips_144_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 09/25/2017] [Indexed: 11/05/2022] Open
Abstract
Aim: The aim of this study is to evaluate the strain developed in simulated mandibular model before and after the joining of an implant-supported screw-retained prosthesis by different joining techniques, namely, arc welding, laser welding, and soldering. Materials and Methods: A specimen simulating a mandibular edentulous ridge was fabricated in heat-cured acrylic resin. 4-mm holes were drilled in the following tooth positions; 36, 33, 43, 46. Implant analogs were placed in the holes. University of California, Los Angeles, abutment was attached to the implant fixture. Eight strain gauges were attached to the acrylic resin model. Six similar models were made. Implant-supported screw-retained fixed prosthesis was fabricated in nickel-chromium alloy. A load of 400 N was applied on the prosthesis using universal testing machine. Resultant strain was measured in each strain gauge. All the prostheses were sectioned at the area between 36 and 33, 33 and 43, and 43 and 46 using 35 micrometer carborundum disc, and strain was measured in each strain gauge after applying a load of 400 N on the prosthesis. Specimens were joined by arc welding, soldering, and laser welding. After joining, a load of 400 N was applied on each prosthesis and the resultant strain was measured in each strain gauge. Results: Highest mean strain values were recorded before sectioning of the prostheses (889.9 microstrains). Lowest mean strain values were recorded after sectioning the prosthesis and before reuniting it (225.0 microstrains). Conclusions: Sectioning and reuniting the long-span implant prosthesis was found to be a significant factor in influencing the peri-implant strain.
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Affiliation(s)
- Ipsha Singh
- KLES's Institute of Dental Sciences, Bengaluru, Karnataka, India
| | | | - Jayakar Shetty
- AECS Maaruti Dental College, Bengaluru, Karnataka, India
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Presotto AGC, Oliveira LV, Pisani MX, Barão VAR, Mesquita MF. Influence of spark erosion on the fit of screw-retained Co-Cr fixed complete denture frameworks veneered with different materials. J Prosthet Dent 2017; 119:797-803. [PMID: 28969917 DOI: 10.1016/j.prosdent.2017.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 07/12/2017] [Accepted: 07/12/2017] [Indexed: 10/18/2022]
Abstract
STATEMENT OF PROBLEM Spark erosion is a fit corrective technology that can be used even after the veneering material has been applied. The framework does not require sectioning, thus preserving its mechanical resistance. However, the spark erosion effect on veneered Co-Cr fixed complete denture (FCD) frameworks has not been investigated. PURPOSE The purpose of this in vitro study was to evaluate whether spark erosion is effective in improving marginal fit on screw-retained Co-Cr FCD frameworks veneered with different materials. A comparison between ceramic applications and simulated ceramic firing cycles was also investigated. MATERIAL AND METHODS Forty FCD frameworks were fabricated with a Co-Cr alloy. Four groups (n=10) were obtained according to the veneer material used on frameworks: HR (heat-polymerized resin); LR (light-polymerized resin); C (ceramic); and SC (simulated ceramic firing cycle). The spark erosion process was conducted for all groups. The marginal fit was analyzed according to the single-screw test protocol, and the measurements were performed at 3 evaluation times: initial, after veneer material application, and after spark erosion process. The results were submitted to a 2-way repeated measures ANOVA and the Tukey honest significant differences test (α=.05). RESULTS Poorer marginal fit (in micrometers) was noted after veneer material application, where the HR and C groups presented the worst values (HR: 170; LR: 72; C: 165; SC: 86; P<.05). The spark erosion process was effective in improving the fit for all groups (HR: 109; LR: 52; C: 110; SC: 60; P<.05). CONCLUSIONS Spark erosion improved the fit of Co-Cr FCD frameworks veneered with different materials. An actual ceramic application should be used to assess distortions generated by veneer material application instead of using only simulated ceramic firing cycles.
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Affiliation(s)
- Anna Gabriella Camacho Presotto
- Graduate student, Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas, São Paulo, Brazil
| | - Luciana Valadares Oliveira
- Associate Professor, Department of Clinical Dentistry, School of Dentistry, Federal University of Bahia, Bahia, Brazil
| | - Marina Xavier Pisani
- Assistant Researcher, Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas, São Paulo, Brazil
| | - Valentim Adelino Ricardo Barão
- Assistant Professor, Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas, São Paulo, Brazil
| | - Marcelo Ferraz Mesquita
- Full Professor, Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas, São Paulo, Brazil.
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The role of welding techniques in the biomechanical behavior of implant-supported prostheses. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017; 78:435-442. [PMID: 28576006 DOI: 10.1016/j.msec.2017.04.090] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 04/14/2017] [Accepted: 04/15/2017] [Indexed: 11/22/2022]
Abstract
This in vitro study investigated the role of welding techniques of implant-supported prostheses in the 2D and 3D marginal misfits of prosthetic frameworks, strain induced on the mini abutment, and detorque of prosthetic screws. The correlations between the analyzed variables were also investigated. Frameworks were cast in commercially pure titanium (cp-Ti). A marginal misfit of 200μm was simulated in the working models (control group) (n=20). The 2D marginal misfit was analyzed according to the single-screw test protocol using a precision optical microscope. The 3D marginal misfit was performed by X-ray microtomography. Strain gauge analysis was performed to investigate the strain induced on the mini abutment. A digital torque meter was used for analysis of the detorque and the mean value was calculated for each framework. Afterwards, the frameworks were divided into two experimental groups (n=10): Laser (L) and TIG (T). The welding techniques were performed according to the following parameters: L (390V/9ms); T (36A/60ms). The L and T groups were reevaluated according to the marginal misfit, strain, and detorque. The results were submitted to one-way ANOVA followed by Tukey's HSD test and Person correlation analysis (α=0.05). Welding techniques statistically reduced the 2D and 3D marginal misfits of prosthetic frameworks (p<0.001), the strain induced on the mini abutment replicas (p=0.006), and improved the screw torque maintenance (p<0.001). Similar behavior was noted between L and T groups for all dependent variables (p>0.05). Positive correlations were observed between 2D and 3D marginal misfit reading methods (r=0.943, p<0.0001) and between misfit and strain (2D r=0.844, p<0.0001 and 3D r=0.864, p<0.0001). Negative correlation was observed between misfit and detorque (2D r=-0.823, p=0.003 and 3D r=-0.811, p=0.005). In conclusion, the welding techniques improved the biomechanical behavior of the implant-supported system. TIG can be an acceptable and affordable technique to reduce the misfit of 3-unit Ti frameworks.
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Presotto AGC, Bhering CLB, Mesquita MF, Barão VAR. Marginal fit and photoelastic stress analysis of CAD-CAM and overcast 3-unit implant-supported frameworks. J Prosthet Dent 2017; 117:373-379. [DOI: 10.1016/j.prosdent.2016.06.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 06/14/2016] [Accepted: 06/15/2016] [Indexed: 10/21/2022]
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Bhering CLB, Marques IDSV, Takahashi JMFK, Barão VAR, Consani RLX, Mesquita MF. The effect of casting and masticatory simulation on strain and misfit of implant-supported metal frameworks. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 62:746-51. [DOI: 10.1016/j.msec.2016.02.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 08/06/2015] [Accepted: 02/11/2016] [Indexed: 11/16/2022]
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Lencioni KA, Macedo AP, Silveira Rodrigues RC, Ribeiro RF, Almeida RP. Photoelastic comparison of as-cast and laser-welded implant frameworks. J Prosthet Dent 2015; 114:652-9. [DOI: 10.1016/j.prosdent.2015.06.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 06/01/2015] [Accepted: 06/04/2015] [Indexed: 11/28/2022]
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Simamoto Júnior PC, Resende Novais V, Rodrigues Machado A, Soares CJ, Araújo Raposo LH. Effect of joint design and welding type on the flexural strength and weld penetration of Ti-6Al-4V alloy bars. J Prosthet Dent 2015; 113:467-74. [PMID: 25749091 DOI: 10.1016/j.prosdent.2014.10.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 10/08/2014] [Accepted: 10/08/2014] [Indexed: 10/23/2022]
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Kokolis J, Chakmakchi M, Theocharopoulos A, Prombonas A, Zinelis S. Mechanical and interfacial characterization of laser welded Co-Cr alloy with different joint configurations. J Adv Prosthodont 2015; 7:39-46. [PMID: 25722836 PMCID: PMC4341185 DOI: 10.4047/jap.2015.7.1.39] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 09/16/2014] [Accepted: 09/18/2014] [Indexed: 11/18/2022] Open
Abstract
PURPOSE The mechanical and interfacial characterization of laser welded Co-Cr alloy with two different joint designs. MATERIALS AND METHODS Dumbbell cast specimens (n=30) were divided into 3 groups (R, I, K, n=10). Group R consisted of intact specimens, group I of specimens sectioned with a straight cut, and group K of specimens with a 45° bevel made at the one welding edge. The microstructure and the elemental distributions of alloy and welding regions were examined by an SEM/EDX analysis and then specimens were loaded in tension up to fracture. The tensile strength (TS) and elongation (ε) were determined and statistically compared among groups employing 1-way ANOVA, SNK multiple comparison test (α=.05) and Weibull analysis where Weibull modulus m and characteristic strength σο were identified. Fractured surfaces were imaged by a SEM. RESULTS SEM/EDX analysis showed that cast alloy consists of two phases with differences in mean atomic number contrast, while no mean atomic number was identified for welded regions. EDX analysis revealed an increased Cr and Mo content at the alloy-joint interface. All mechanical properties of group I (TS, ε, m and σο) were found inferior to R while group K showed intermediated values without significant differences to R and I, apart from elongation with group R. The fractured surfaces of all groups showed extensive dendritic pattern although with a finer structure in the case of welded groups. CONCLUSION The K shape joint configuration should be preferred over the I, as it demonstrates improved mechanical strength and survival probability.
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Affiliation(s)
- John Kokolis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian, University of Athens, Greece. ; Department of Dental Technology, Technological Educational Institution of Athens, Greece
| | | | | | - Anthony Prombonas
- Department of Dental Technology, Technological Educational Institution of Athens, Greece
| | - Spiros Zinelis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian, University of Athens, Greece
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Correlation Between Vertical Misfits and Stresses Over Implants From Castable Frameworks Made of Different Alloys. J Craniofac Surg 2014; 25:2062-5. [DOI: 10.1097/scs.0000000000001194] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Tiossi R, Gomes ÉA, Lapria Faria AC, Silveira Rodrigues RC, Ribeiro RF. Effect of cyclic loading on the vertical microgap of long-span zirconia frameworks supported by 4 or 6 implants. J Prosthet Dent 2014; 112:828-33. [DOI: 10.1016/j.prosdent.2014.03.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 03/06/2014] [Accepted: 03/06/2014] [Indexed: 11/30/2022]
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Mohunta VV, Stevenson JA, Lee DJ. Replacing worn overdenture abutments of an unknown implant system by using laser welding: a clinical report. J Prosthet Dent 2014; 112:686-8. [PMID: 24836281 DOI: 10.1016/j.prosdent.2014.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 04/08/2014] [Accepted: 04/08/2014] [Indexed: 11/26/2022]
Abstract
This clinical report describes a procedure for replacing worn ball abutments with low-profile resilient abutments by using laser welding when the implant system for a mandibular implant-supported overdenture could not be identified.
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Affiliation(s)
- Vrinda V Mohunta
- Resident, Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio
| | - James A Stevenson
- Dental laboratory supervisor, College of Dentistry, The Ohio State University, Columbus, Ohio
| | - Damian J Lee
- Assistant Professor, Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio.
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Alvarez A, Lafita P, de Llanos H, Gago A, Brizuela A, Ellacuria JJ. A Comparison of Two Soldering Techniques on the Misfit of Bar-Retained Implant-Supported Overdentures. J Prosthodont 2013; 23:163-70. [DOI: 10.1111/jopr.12083] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2013] [Indexed: 11/29/2022] Open
Affiliation(s)
- Angel Alvarez
- Department of Prosthodontics and Occlusion, School of Dentistry; University of Oviedo; Oviedo Spain
| | - Pedro Lafita
- Department of Prosthodontics and Occlusion, School of Dentistry; University of Oviedo; Oviedo Spain
| | - Hector de Llanos
- Department of Prosthodontics and Occlusion, School of Dentistry; University of Oviedo; Oviedo Spain
| | - Angel Gago
- Department of Prosthodontics and Occlusion, School of Dentistry; University of Oviedo; Oviedo Spain
| | - Aritza Brizuela
- Department of Stomatology, School of Medicine and Dentistry; University of Basque Country; Leioa Spain
| | - Joseba J. Ellacuria
- Department of Stomatology, School of Medicine and Dentistry; University of Basque Country; Leioa Spain
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Andrade PCARD, Luthi LF, Stanley K, Cardoso AC. A new portable vibrator for plaster pouring: effect on the marginal fit at cylinder-abutment. J Appl Oral Sci 2012; 20:517-21. [PMID: 23138736 PMCID: PMC3881794 DOI: 10.1590/s1678-77572012000500004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 09/05/2011] [Indexed: 11/29/2022] Open
Abstract
Objective The aim of this study was to test a new portable vibrator for plaster pouring
(developed for this purpose), comparing the effect of its use on the accuracy of
working cast of implant-supported restorations to the conventional vibrator. Material and methods From a master cast with 2 implants, 30 transfer moldings were made randomly and
divided into three groups: Group I (GI): pouring performed in an outsourced dental
laboratory with conventional plaster vibrator (10 casts), Group II (GII): pouring
performed in the laboratory of the Federal University of Santa Catarina (UFSC)
with conventional plaster vibrator (10 casts) and Group III (GIII): pouring
performed with the portable vibrator fabricated for this study (10 casts). The
position of the analogue and marginal adaptation of the infrastructure were
verified by testing the single screw on the master model and on the working model.
The measurement of misfit was blindly performed with a precision microscope and
analyzing unit, Quadra-Check 200. The data were statistically analyzed by analysis
of variance (ANOVA) and the Holm-Sidak test (α=0.05). Results Means±standard deviations were as follows: GI: 19.19±4.73 µm; GII: 21.72±5.41 µm;
GIII: 13.5±2.39 µm (P<0.05), with GIII significantly lower as compared to the
other groups. Conclusion Within the limitations of this study, it was concluded that a greater accuracy of
working cast was achieved when a portable vibrator was used for casting molds.
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A Novel Framework to Eliminate the Effects of Casting Distortion when Fabricating a Fixed, Detachable Screw-Retained Prosthesis. J Prosthodont 2012; 21:478-81. [DOI: 10.1111/j.1532-849x.2012.00885.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Tiossi R, Falcão-Filho HBL, de Aguiar FA, Rodrigues RCS, de Mattos MDGC, Ribeiro RF. Prosthetic misfit of implant-supported prosthesis obtained by an alternative section method. J Adv Prosthodont 2012; 4:89-92. [PMID: 22737313 PMCID: PMC3381208 DOI: 10.4047/jap.2012.4.2.89] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 05/02/2012] [Accepted: 05/07/2012] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Adequate passive-fitting of one-piece cast 3-element implant-supported frameworks is hard to achieve. This short communication aims to present an alternative method for section of one-piece cast frameworks and for casting implant-supported frameworks. MATERIALS AND METHODS Three-unit implant-supported nickel-chromium (Ni-Cr) frameworks were tested for vertical misfit (n = 6). The frameworks were cast as one-piece (Group A) and later transversally sectioned through a diagonal axis (Group B) and compared to frameworks that were cast diagonally separated (Group C). All separated frameworks were laser welded. Only one side of the frameworks was screwed. RESULTS The results on the tightened side were significantly lower in Group C (6.43 ± 3.24 µm) when compared to Groups A (16.50 ± 7.55 µm) and B (16.27 ± 1.71 µm) (P<.05). On the opposite side, the diagonal section of the one-piece castings for laser welding showed significant improvement in the levels of misfit of the frameworks (Group A, 58.66±14.30 µm; Group B, 39.48±12.03 µm; Group C, 23.13±8.24 µm) (P<.05). CONCLUSION Casting diagonally sectioned frameworks lowers the misfit levels. Lower misfit levels for the frameworks can be achieved by diagonally sectioning one-piece frameworks.
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Affiliation(s)
- Rodrigo Tiossi
- Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
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Barbosa GAS, Neves FDD, Mattos MDGCD, Rodrigues RCS, Ribeiro RF. Implant/abutment vertical misfit of one-piece cast frameworks made with different materials. Braz Dent J 2010; 21:515-9. [DOI: 10.1590/s0103-64402010000600006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study compared vertical and passive fit of one-piece cast frameworks made with 3 different materials: commercially pure titanium (CP Ti - G1), cobalt-chromium alloy (Co-Cr - G2) and nickel-chromium-titanium alloy (Ni-Cr-Ti - G3). Fifteen frameworks were obtained simulating bars for fixed prosthesis in a model with 5 implants. The passive and vertical fit of the framework interface was measured using an optical microscope at ×30 magnification. Data were statistically analyzed by ANOVA and LSD tests (α=0.05). Mean and standard deviation values for passive fit and vertical fit were, respectively: G1 [472.49 (109.88) µm and 29.9 (13.24) µm], G2 [584.84 (120.20) µm and 27.05 (10.30) µm], and G3 [462.70 (179.18) µm and 24.95 (11.14) µm]. For vertical fit, there were no significant differences among G1, G2 and G3 (p=0.285). There were no significant differences for passive fit between G1 and G3 (p=0.844), but both differed significantly from G2 (p=0.028 and p=0.035, respectively), which showed the highest misfit values. It may be concluded that the vertical fit of frameworks was not affected by the tested materials, and that one-piece cast frameworks resulted in inadequate passive fit. The Co-Cr alloy presented the worst values for passive fit.
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