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Effect of ceramic layering on the fit of cobalt-chromium alloy 3-unit fixed dental prostheses fabricated by additive, soft milling, and casting technologies. J Prosthet Dent 2021; 126:130.e1-130.e7. [PMID: 34034899 DOI: 10.1016/j.prosdent.2021.03.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 03/16/2021] [Accepted: 03/16/2021] [Indexed: 11/22/2022]
Abstract
STATEMENT OF PROBLEM The change in fit after ceramic layering of additively manufactured cobalt-chromium alloy frameworks has not been evaluated extensively. PURPOSE The purpose of this in vitro study was to compare the fit of cobalt-chromium alloy fixed dental prostheses fabricated by different techniques before and after ceramic layering. MATERIAL AND METHODS A cobalt-chromium alloy master model was prepared to receive a 3-unit fixed dental prosthesis. Sixty cobalt-chromium alloy frameworks (N=60) were manufactured by using 3 manufacturing techniques (n=20): selective laser melting (Mediloy S-Co), soft milling (Ceramill Sintron), and conventional casting as the control group (Girobond NB). The replica technique was used to measure the marginal and internal discrepancies. The frameworks were then layered with ceramic, and the same fit measuring procedure was repeated. The results were compared before and after ceramic layering within each group. The data were analyzed using the Levene, ANOVA, and paired-samples t tests (α=.05). RESULTS A significant difference was found within groups before and after ceramic layering for selective laser melting (P=.006) and soft milling (P=.009) but not for conventional casting (P>.05). No statistical difference was reported in the marginal region for conventional casting group (P=.155) in contrast with the soft milling and selective laser melting groups (P=.003). Soft milling showed increased gap values in the marginal (P=.006) and occlusal regions (P=.004). CONCLUSIONS Ceramic layering increased the discrepancy of the laser-sintered and milled frameworks, increasing the marginal discrepancy.
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Daou EE, Baba NZ. Fit Alteration of Presintered Co-Cr and Zirconia Multiple-Unit Prostheses After Ceramic Layering. J Prosthodont 2021; 30:789-794. [PMID: 33486845 DOI: 10.1111/jopr.13336] [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] [Accepted: 01/12/2021] [Indexed: 11/30/2022] Open
Abstract
PURPOSE The fit alteration after ceramic layering of soft Cobalt-Chromium (Co-Cr) and zirconia is poorly documented. This study compared the marginal and internal fit of presintered Co-Cr and zirconia three-unit fixed dental prostheses before and after ceramic veneering. MATERIALS AND METHODS Co-Cr master model was prepared and duplicated 60 times to receive three-unit fixed dental prostheses (FDPs). Sixty dies were prepared, scanned and assigned to 3 groups (n = 20/group), to receive the FDPs made of presintered Co-Cr (CS), presintered zirconia (CZ) and cast Ni-Cr (Wi). Each framework was seated on its specific cast. A replica technique was used for marginal and internal discrepancy measurements in mesiodistal and buccolingual planes. Frameworks were ceramic veneered. Results were compared before and after ceramic layering within each group. Data were analyzed using the Levene, t test, and ANOVA (α = 0.05). RESULTS Significant difference was found when gaps were compared within groups for CS and CZ but not for Wi. At the abutments level, significant difference was found for both premolars and molars in the buccolingual planes (p < 0.001). A multiple comparison between materials tested showed significant differences between presintered and cast Ni-Cr. No significant difference was detected between CS and CZ (p = 1.000). CONCLUSIONS Although ceramic layering increased the discrepancy for presintered Co-Cr and zirconia, the marginal adaptation remained clinically acceptable.
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Affiliation(s)
- Elie E Daou
- Department of Prosthodontics Faculty of Dentistry, Faculty of Dental Medicine, Beirut, Lebanon
| | - Nadim Z Baba
- Advanced Specialty Education Program in Implant Dentistry, School of Dentistry, Loma Linda University, Loma Linda, CA
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Altintas MA, Akin H. Effect of repetitive firing on passive fit of metal substructure produced by the laser sintering in implant-supported fixed prosthesis. J Adv Prosthodont 2020; 12:167-172. [PMID: 32601536 PMCID: PMC7314632 DOI: 10.4047/jap.2020.12.3.167] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 03/07/2020] [Accepted: 03/20/2020] [Indexed: 12/02/2022] Open
Abstract
PURPOSE The aim of the present study was to investigate the passive fit of metal substructure after repetitive firing processes in implant-supposed prosthesis. MATERIALS AND METHODS Five implants (4 mm diameter and 10 mm length) were placed into the resin-based mandibular model and 1-piece of screw-retained metal substructure was produced with the direct metal laser sintering (DMSL) method using Co-Cr compound (n = 10). The distance between the marked points on the multiunit supports and the marginal end of the substructure was measured using a scanning electron microscope (SEM) at each stage (metal, opaque, dentin, and glaze). 15 measurements were taken from each prosthesis, and 150 measurements from 10 samples were obtained. In total, 600 measurements were carried out at 4 stages. One-way ANOVA test was used for statistical evaluation of the data. RESULTS When the obtained marginal range values were examined, differences between groups were found to be statistically significant (P<.001). The lowest values were found in the metal stage (172.4 ± 76.5 µm) and the highest values (238.03 ± 118.92 µm) were determined after glaze application. When the interval values for groups are compared with pairs, the differences between metal with dentin, metal with glaze, opaque with dentin, opaque with glaze, and dentin with glaze were found to be significant (P<.05), whereas the difference between opaque with metal was found to be insignificant (P=.992). CONCLUSION Passive fit of 1-piece designed implant-retained fixed prosthesis that is supported by multiple implants is negatively affected by repetitive firing processes.
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Affiliation(s)
- Musa Aykut Altintas
- Department of Prosthodontics, Faculty of Dentistry, Cumhuriyet University, Sivas, Turkey
| | - Hakan Akin
- Department of Prosthodontics, Faculty of Dentistry, Sakarya University, Sakarya, Turkey
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Evaluation of marginal adaptation of Co-Cr-Mo metal crowns fabricated by traditional method and computer-aided technologies. J Dent Sci 2019; 14:288-294. [PMID: 31528257 PMCID: PMC6742603 DOI: 10.1016/j.jds.2018.11.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 10/19/2018] [Indexed: 11/26/2022] Open
Abstract
Background/purpose The purpose of this study was to evaluate the marginal gaps of dental restorations manufactured using conventional loss wax and casting, computer-aided design/computer-aided manufacturing (CAD/CAM), and 3D printing methods. Materials and methods A zirconia master die model with an upper right first molar resin crown was prepared as a standardized model. A total of 30 resin master die models were duplicated from this standard model. Simultaneously, 10 Co—Cr—Mo metal crowns were individually obtained using the conventional loss wax and casting method (Group A), selective laser sintering (Group B), and CAD/CAM (Group C), respectively. The marginal gaps between the crowns fabricated conventional and digital methods with master die models were calculated using a 3D replica and mapping technique. Results Statistical analyses revealed there were significant differences in the marginal gaps in the group A with group B and C (p < 0.05). The mean marginal gaps between dental crowns with die models were 76 ± 61 μm, 116 ± 92 μm, and 121 ± 98 μm for groups A, B, and C, respectively. Conclusion Within the limitations of this study, the marginal gaps were clinical acceptable in conventional and digital techniques.
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Hong MH, Min BK, Lee DH, Kwon TY. Marginal fit of metal-ceramic crowns fabricated by using a casting and two selective laser melting processes before and after ceramic firing. J Prosthet Dent 2019; 122:475-481. [PMID: 30982615 DOI: 10.1016/j.prosdent.2019.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 02/19/2019] [Accepted: 03/04/2019] [Indexed: 12/12/2022]
Abstract
STATEMENT OF PROBLEM Few studies have investigated changes in the marginal fit of metal-ceramic restorations fabricated by selective laser melting (SLM) techniques after the application of veneering ceramic. PURPOSE The purpose of this in vitro study was to evaluate the marginal fit (silicone replica technique) and internal porosity (cross-section analysis) of cobalt-chromium (Co-Cr) alloy metal crowns prepared by using 2 SLM processes together with a casting technique before and after ceramic veneering. MATERIAL AND METHODS Cast single Co-Cr crowns and SLM-processed crowns with large (SLML) or small (SLMS) porosity were prepared (n=20/group), and half were subjected to ceramic veneering. On a single Co-Cr master die, the marginal discrepancy (MD) and absolute marginal discrepancy (AMD) of the crowns were measured by using the silicone replica technique, in which each replica was cut into 4 sections before and after ceramic veneering (n=10 for each subgroup). After marginal fit measurements, each metal coping was cross-sectioned into 4 parts, and 5 rectangular optical microscope images were acquired on both outer corners of each quarter. The porosity was then calculated as the ratio of the black-to-white pixels on the binarized images. The data were analyzed by 2-way ANOVA and the post hoc test (Tukey or Student t test) (α=.05). RESULTS Before ceramic veneering, the 2 SLM groups showed significantly larger MDs than the casting group (56.4 ±10.4 μm) (P<.05). A significant increase in MD after ceramic veneering was detected only in the SLML group (P<.001). The AMD values showed a similar trend with MD values. The 2 SLM groups (in particular, SLML) showed a significantly higher amount of porosity than the casting group before ceramic veneering (P<.001). Only the SLML group showed a significant decrease in the amount of porosity after ceramic veneering (P<.001). CONCLUSIONS Within the limitations of this in vitro study, large internal porosity within the SLM-fabricated Co-Cr metal copings affected the marginal fit of the metal-ceramic crowns. However, all the MD values of the 3 groups were lower than the acceptable range even after the application of veneering ceramic.
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Affiliation(s)
- Min-Ho Hong
- Postdoctoral Researcher, Institute for Biomaterials Research and Development, Kyungpook National University, Daegu, Republic of Korea
| | - Bong Ki Min
- Senior Researcher, Center for Research Facilities, Yeungnam University, Gyeongsan, Republic of Korea
| | - Du-Hyeong Lee
- Associate Professor, Department of Prosthodontics, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Tae-Yub Kwon
- Professor, Department of Dental Biomaterials, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea.
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Kocaağaoğlu H, Kılınç Hİ, Albayrak H, Kara M. In vitro evaluation of marginal, axial, and occlusal discrepancies in metal ceramic restorations produced with new technologies. J Prosthet Dent 2016; 116:368-74. [DOI: 10.1016/j.prosdent.2016.03.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 03/17/2016] [Accepted: 03/18/2016] [Indexed: 10/21/2022]
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Tamam E, Aydın AK, Bilgiç S. The Effect of Porcelain Firing on Electrochemical Behavior of a Dental Alloy in Hydrogen Peroxide. J Prosthodont 2014; 24:401-6. [PMID: 25313456 DOI: 10.1111/jopr.12215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2014] [Indexed: 11/29/2022] Open
Abstract
PURPOSE The aim of this study was to evaluate changes in electrochemical corrosion properties of porcelain firing simulated nickel-chromium dental casting alloy exposed to a 10% hydrogen peroxide bleaching agent. MATERIALS AND METHODS The electrochemical corrosion behavior of a Ni-Cr alloy was evaluated by cyclic polarization test in the aerated electrolyte (pH = 6.5). Test groups were produced in as-cast (group 1, control group) and simulated porcelain firing (group 2: heat-treated/mean value; group 3: heat-treated/cycle) conditions. Scanning electron microscopy (SEM) was also used to examine the alloy surfaces before and after the corrosion test. RESULTS The ranking of the groups with respect to Ecorr and Icorr was as follows: 1, 2, 3 and 3, 1, 2, respectively. Group 3 exhibited the greatest and group 2 displayed the least corrosion tendencies. An increase in corrosion rates was observed after heat treatment/cycle state. Post-corrosion SEM photographs were also consistent with the test results. CONCLUSION Within the parameters of this study, a single heat treatment is insufficient to cause upheaval in corrosion behavior of a Ni-Cr alloy subjected to 10% hydrogen peroxide.
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Affiliation(s)
- Evşen Tamam
- Department of Prosthodontics, Faculty of Dentistry, Gazi University, Ankara, Turkey
| | - A Kevser Aydın
- Department of Prosthodontics, Faculty of Dentistry, Ankara University, Ankara, Turkey
| | - Semra Bilgiç
- Department of Physical Chemistry, Faculty of Dentistry, Ankara University, Ankara, Turkey
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Kim KB, Kim JH, Kim WC, Kim HY, Kim JH. Evaluation of the marginal and internal gap of metal-ceramic crown fabricated with a selective laser sintering technology: two- and three-dimensional replica techniques. J Adv Prosthodont 2013; 5:179-86. [PMID: 23755345 PMCID: PMC3675292 DOI: 10.4047/jap.2013.5.2.179] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 04/26/2013] [Accepted: 05/07/2013] [Indexed: 11/12/2022] Open
Abstract
PURPOSE One of the most important factors in evaluating the quality of fixed dental prostheses (FDPs) is their gap. The purpose of this study was to compare the marginal and internal gap of two different metal-ceramic crowns, casting and selective laser sintering (SLS), before and after porcelain firing. Furthermore, this study evaluated whether metal-ceramic crowns made using the SLS have the same clinical acceptability as crowns made by the traditional casting. MATERIALS AND METHODS The 10 study models were produced using stone. The 20 specimens were produced using the casting and the SLS methods; 10 samples were made in each group. After the core gap measurements, 10 metal-ceramic crowns in each group were finished using the conventional technique of firing porcelain. The gap of the metal-ceramic crowns was measured. The marginal and internal gaps were measured by two-dimensional and three-dimensional replica techniques, respectively. The Wilcoxon signed-rank test, the Wilcoxon rank-sum test and nonparametric ANCOVA were used for statistical analysis (α=.05). RESULTS In both groups, the gap increased after completion of the metal-ceramic crown compared to the core. In all measured areas, the gap of the metal cores and metal-ceramic crowns produced by the SLS was greater than that of the metal cores and metal-ceramic crowns produced using the casting. Statistically significant differences were found between cast and SLS (metal cores and metal-ceramic crown). CONCLUSION Although the gap of the FDPs produced by the SLS was greater than that of the FDPs produced by the conventional casting in all measured areas, none exceeded the clinically acceptable range.
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Affiliation(s)
- Ki-Baek Kim
- Department of Dental Laboratory Science and Engineering, Korea University, Seoul, Republic of Korea
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Baig MR, Gunaseelan R. Metal-Ceramic Screw-Retained Implant Fixed Partial Denture With Intraoral Luted Framework to Improve Passive Fit. J ORAL IMPLANTOL 2012; 38:149-53. [DOI: 10.1563/aaid-joi-d-09-00089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Passive fit of a long-span screw-retained implant prosthesis is an important criteria for the success of the restoration. This article describes a technique for fabricating a ceramometal implant fixed dental prosthesis (FDP) for a long-span partially edentulous situation by altering the conventional screw-retained design. The possibility of a passive fit is maximized by intraoral luting of the cast frame to milled abutments, and the potential framework distortion during fabrication is compensated to a major extent. Retrievability is ensured by screw retention of the prosthesis to the implants. Compared with conventional porcelain fused to metal screw-retained FDP, this prosthesis is relatively inexpensive to fabricate.
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Affiliation(s)
- Mirza Rustum Baig
- Department of Prosthetic Dentistry, Faculty of Dentistry, University Malaya, Kuala Lumpur, Malaysia; and Department of Prosthodontics, Ragas Dental College and Hospital, Chennai, India
| | - Rajan Gunaseelan
- Oral and Maxillofacial Surgery, Rajan Dental Institute, Chennai, India
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Naveen HC, Pillai LK, Porwal A, Nadiger RK, Guttal SS. Effect of porcelain-firing cycles and surface finishing on the marginal discrepancy of titanium copings. J Prosthodont 2011; 20:101-5. [PMID: 21261776 DOI: 10.1111/j.1532-849x.2010.00668.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
PURPOSE The aim of the study was to evaluate the effect of simulated porcelain firing cycles and surface finishing on the marginal fit of commercially pure titanium (Cp Ti) copings. MATERIALS AND METHODS A machined stainless steel die system with standard 0.5-mm copings was fabricated. Wax patterns were prepared by pouring the molten wax on a two-part stainless steel die. Thirty specimens were cast in Cp Ti. These were divided into three groups with ten specimens in each group. Group 1 was treated with conventional cold working and later oxidized. Group 2 specimens were oxidized initially and then cold worked. Group 3 was heat treated in its original investment and later treated as in group 1. All specimens were later subjected to sequential simulated porcelain firing cycles, that is, oxidation, bonder, opaque, body, and glaze firing. Following the completion of each firing cycle, marginal discrepancy was measured in μm using a traveling microscope. The obtained data were subjected to one-way analysis of variance (ANOVA) and Student's t-test. The statistical level of significance was set at 1%. RESULTS The results showed that the mean and SD values (in μm) were 55 ± 2.6, 43 ± 3.0, and 68 ± 4.0 after oxidation for groups 1, 2, and 3, respectively. Mean and SD values (in μm) after glaze firing were 76 ± 3.9, 64 ± 4.1, and 89 ± 4.3 for groups 1, 2, and 3, respectively. The mean marginal opening was largest for group 3 specimens. One-way ANOVA showed the difference within the three groups was highly significant after oxidation (F-value 149.37 at p-value 0.0000) and glaze firing (F-value 82.43 at p-value 0.0000). CONCLUSIONS (1) The Student's t-test values demonstrated that increased marginal openings of the specimens resulted after the sequential simulated porcelain firing cycles. (2) Marginal discrepancy values improved when the specimens were thermocycled prior to cold working.
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Affiliation(s)
- Halemane C Naveen
- Department of Prosthodontics, Vasant Dada Patil Dental College and Hospital, Sangli, Maharashtra, India
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Chen H, Lowe AA, de Almeida FR, Wong M, Fleetham JA, Wang B. Three-dimensional computer-assisted study model analysis of long-term oral-appliance wear. Part 1: Methodology. Am J Orthod Dentofacial Orthop 2008; 134:393-407. [PMID: 18774086 DOI: 10.1016/j.ajodo.2006.10.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Revised: 10/01/2006] [Accepted: 10/01/2006] [Indexed: 10/21/2022]
Abstract
INTRODUCTION The aim of this study was to test a 3-dimensional (3D) computer-assisted dental model analysis system that uses selected landmarks to describe tooth movement during treatment with an oral appliance. METHODS Dental casts of 70 patients diagnosed with obstructive sleep apnea and treated with oral appliances for a mean time of 7 years 4 months were evaluated with a 3D digitizer (MicroScribe-3DX, Immersion, San Jose, Calif) compatible with the Rhinoceros modeling program (version 3.0 SR3c, Robert McNeel & Associates, Seattle, Wash). A total of 86 landmarks on each model were digitized, and 156 variables were calculated as either the linear distance between points or the distance from points to reference planes. Four study models for each patient (maxillary baseline, mandibular baseline, maxillary follow-up, and mandibular follow-up) were superimposed on 2 sets of reference points: 3 points on the palatal rugae for maxillary model superimposition, and 3 occlusal contact points for the same set of maxillary and mandibular model superimpositions. The patients were divided into 3 evaluation groups by 5 orthodontists based on the changes between baseline and follow-up study models. RESULTS Digital dental measurements could be analyzed, including arch width, arch length, curve of Spee, overbite, overjet, and the anteroposterior relationship between the maxillary and mandibular arches. A method error within 0.23 mm in 14 selected variables was found for the 3D system. The statistical differences in the 3 evaluation groups verified the division criteria determined by the orthodontists. CONCLUSIONS The system provides a method to record 3D measurements of study models that permits computer visualization of tooth position and movement from various perspectives.
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Affiliation(s)
- Hui Chen
- Department of Orthodontics, Faculty of Stomatology, Capital University of Medical Sciences, Beijing, China.
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