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Al Jabbari YS, Dimitriadis K, Sufyan A, Zinelis S. Microstructural and mechanical characterization of six Co-Cr alloys made by conventional casting and selective laser melting. J Prosthet Dent 2024; 132:646.e1-646.e10. [PMID: 38955601 DOI: 10.1016/j.prosdent.2024.06.015] [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: 12/15/2023] [Revised: 06/12/2024] [Accepted: 06/13/2024] [Indexed: 07/04/2024]
Abstract
STATEMENT OF PROBLEM Three Co-Cr alloy types (Co-Cr-Mo, Co-Cr-W, and Co-Cr-Mo-W) have been commonly used in the fabrication of dental prostheses. These alloys can be manufactured using either conventional casting or selective laser melting (SLM) techniques. Nevertheless, research that directly compares these materials and/or manufacturing processes in terms of their microstructural and mechanical characteristics is sparse. PURPOSE The purpose of this in vitro study was to conduct microstructural and mechanical analysis via X-ray interpretation, optical microscopy, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS), image analysis, X-ray diffraction (XRD), instrumented indentation testing (IIT), and 3-point bending testing to characterize Co-Cr-Mo, Co-Cr-W, and Co-Cr-Mo-W alloys produced through conventional casting and SLM. MATERIAL AND METHODS Six Co-Cr-based alloys were analyzed and divided into 3 types based on their elemental composition (Co-Cr-Mo, Co-Cr-W, and Co-Cr-Mo-W). Additionally, each group was categorized based on the manufacturing process used (casting or SLM). X-ray scans were used to assess porosity. The microstructures of the specimens were assessed through SEM/EDS examination and XRD analysis. IIT was used to determine the Martens hardness (HM) and elastic index (ηIT), while the elastic modulus (E) was estimated through the 3-point bending test. The mechanical properties were statistically analyzed using 2-way analysis of variance (ANOVA) and the Tukey multiple comparison post hoc test, with alloy type and manufacturing process as discriminating variables (α=.05). RESULTS All cast groups exhibited gross porosity, while no pores or other flaws were found in the SLM groups. Based on the XRD results, the crystalline structure of all Co-Cr specimens consisted of the face-centered cubic γ phase (γ-fcc), along with the hexagonal close-packed ε phase (ε-hcp) and Cr23C6 carbide. Different microstructures were identified between the cast and SLM alloys. Significant differences were identified for the mean standard deviation HM (ranging from 2601 ±94 N/mm2 to 3633 ±61 N/mm2) and mean ±standard deviation ηIT (ranging from 16.8 ±0.3% to 20.9 ±0.3%) among alloys prepared by the same manufacturing process, while all SLM alloys had statistically higher HM and ηIT results than their cast counterparts (P<.05). No statistically significant differences were identified for the mean ±standard deviation Eb (ranging from 170 ±25 GPa to 244 ±36 GPa) among the groups prepared with the same manufacturing process (P>.05), but the SLM alloys had significantly higher results (P<.05) than the cast alloys. CONCLUSIONS In general, the manufacturing procedure significantly affected the porosity, microstructure, and mechanical properties of the tested Co-Cr alloys. SLM decreased the internal porosity, provided a uniform microstructure, and improved the mechanical properties for all the tested alloy types.
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Affiliation(s)
- Youssef S Al Jabbari
- Director, Dental Biomaterials Research and Development Chair and Professor, Prosthetic Dental Sciences Department, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
| | - Konstantinos Dimitriadis
- Research fellow, Department of Biomaterials, School of Dentistry, National and Kapodistrian Universty of Athens, Athens, Greece
| | - Aref Sufyan
- Researcher, Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Spiros Zinelis
- Professor, Department of Biomaterials, School of Dentistry, National and Kapodistrian Universty of Athens, Athens, Greece and International Professor of Dental Biomaterials Research and Development Chair, King Saud University, Riyadh, Saudi Arabia
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Kim GY, Moon HS, Kwon JS, Oh KC. An in vitro evaluation of bond strength and failure behavior between 3D-printed cobalt-chromium alloy and different types of denture base resins. J Dent 2024; 147:105119. [PMID: 38852694 DOI: 10.1016/j.jdent.2024.105119] [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: 09/18/2023] [Revised: 06/05/2024] [Accepted: 06/07/2024] [Indexed: 06/11/2024] Open
Abstract
OBJECTIVES This study aimed to evaluate the shear bond strength and failure behavior between cobalt-chromium (Co-Cr) alloy and different types of denture base resins (DBRs) over time. METHODS Seventy-two disk-shaped specimens (8 mm in diameter and 2 mm in thickness) were manufactured using a selective laser melting technology-based metal 3D printer. Three types of DBRs were used: heat-cure (HEA group), cold-cure (COL group), and 3D-printable (TDP group) DBRs (n = 12 per group). Each DBR specimen was fabricated as a 5 mm × 5 mm × 5 mm cube model. The specimens of the TDP group were manufactured using a digital light processing technology-based 3D printer. Half of the DBRs were stored in distilled water at 37 °C for 24 h, whereas the remaining half underwent thermocycling for 10,000 cycles. Shear bond strength was measured using a universal testing machine; failure modes were observed, and metal surfaces were evaluated using energy dispersive spectrometry. RESULTS The shear bond strength did not differ between the DBR types within the non-thermocycled groups. Contrarily, the TDP group exhibited inferior strength compared to the HEA group (P = 0.008) after thermocycling. All three types of DBRs exhibited a significant decrease in the shear bond strength and an increased tendency toward adhesive failure after thermocycling. CONCLUSIONS The bond strength between 3D-printable DBRs and Co-Cr alloy was comparable to that of heat-and cold-cure DBRs before thermocycling. However, it exhibited a considerable weakening in comparison to heat-cure DBRs after simulated short-term use. CLINICAL SIGNIFICANCE The application of 3D-printable DBR in metal framework-incorporated removable partial dentures may be feasible during the early phase of the treatment. However, its application is currently limited because the bond strength between the 3D-printable DBR and metal may weaken after short-term use. Further studies on methods to increase the bond strength between these heterogeneous materials are required.
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Affiliation(s)
- Gi Youn Kim
- Department of Prosthodontics, Yonsei University College of Dentistry, Seoul, Republic of Korea
| | - Hong-Seok Moon
- Department of Prosthodontics, Yonsei University College of Dentistry, Seoul, Republic of Korea
| | - Jae-Sung Kwon
- Department and Research Institute of Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry, Seoul, Republic of Korea
| | - Kyung Chul Oh
- Department of Prosthodontics, Yonsei University College of Dentistry, Seoul, Republic of Korea.
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Garcia CV, Souza DN, Andrade ER. Influence of the Method of Calculating the Effective Atomic Number on the Estimate of Fluorescence Yield for Metal Alloys of Biomedical Interest. HEALTH PHYSICS 2024; 126:188-195. [PMID: 38252033 DOI: 10.1097/hp.0000000000001789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
ABSTRACT This study evaluates the influence of the method used to calculate the effective atomic number (Z eff ) on the estimate of secondary radiation yielded under kilovoltage x-ray beams by metal alloys with a wide range of biomedical applications. Two methods for calculating Z eff (referred to here as M 1 and M 2 ) are considered, and six metallic alloys are investigated: Ti-6Al-4 V, Co-Cr-Mo, Ni-Cr-Ti, Ni-Cr, Co-Cr-Mo-W, and Ag 3 Sn-Hg (amalgam). The results indicate significant differences in the estimates of fluorescence yield depending on the method used to estimate Z eff for each metallic alloy. Both the choice of the calculation method for Z eff and the energy ranges of the incident radiation are essential factors affecting the behavior of alloys in terms of fluorescence production. Our results may guide the selection of the best material for a biomedical application. The metallic alloys simulated here show equivalences and discrepancies that depend on the method used to estimate Z eff and the energy range of the incident photons. This finding allows for the creation of combinations of alloys and methods for calculating Z eff and the photon energy to maximize safety and minimize cost.
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Affiliation(s)
- Caroline V Garcia
- Departamento de Física, Universidade Federal de Sergipe, São Cristóvão, SE, Brazil
| | - Divanizia N Souza
- Departamento de Física, Universidade Federal de Sergipe, São Cristóvão, SE, Brazil
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Muhsin SA, Mohammed EK, Bander K. Finite Element Analysis: Connector Designs and Pontic Stress Distribution of Fixed Partial Denture Implant-Supported Metal Framework. J Long Term Eff Med Implants 2024; 34:33-47. [PMID: 38842231 DOI: 10.1615/jlongtermeffmedimplants.2023048378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2024]
Abstract
This virtual study was designed to evaluate the stress-deformation of a metal fixed partial dentures (FPDs) pontic under different loads using two different connectors. The STL file was generated for a RPD of two implant-supported restorations. The Co-Cr metal substructure was designed with two types of connector design. The pontic is connected to implant-supported crowns with square and round shape connectors. This study was designed for a cementless-retained implant-supported FPD. Finite element modeling (FEM) is used to assess the stress and deformation of the pontic within a metal substructure as the FEM might provide virtual values that could have laboratory and clinical relevance. The Co-Cr alloy mechanical properties like the Poisson ratio and modulus of elasticity were based on the parameters of the three-dimensional structure additive method. Nonparametric analyses (Mann-Whitney U test) was used. The use of square or round connectors often resulted in non-significant changes in stress, and deformation under either three or each loaded point on the occlusal surface of a pontic (P > 0.05). However, the deformation revealed distinct variations between loads of the three points compared to each loaded point (P ≤ 0.05). According to this study data, the pontic occlusal surface appears to be the same in stress and deformation under different loads depending on whether square or round connectors are used. While at the same connector designs, the pontic occlusal surface deformed significantly at three loaded points than it did at each point.
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Affiliation(s)
| | | | - Khalid Bander
- Middle Technical University, College of Health and Medical Techniques, Baghdad, Iraq
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Effect of internal design changes on the mechanical properties of laser-sintered cobalt-chromium specimens. J Prosthet Dent 2023; 129:508-512. [PMID: 34294419 DOI: 10.1016/j.prosdent.2021.06.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/10/2021] [Accepted: 06/10/2021] [Indexed: 11/23/2022]
Abstract
STATEMENT OF PROBLEM Changing the internal design of a metal framework may decrease the manufacturing time, the weight of the restoration, and the amount of alloy powder used, as well as simplify the fabrication process. PURPOSE The purpose of this in vitro study was to evaluate the effect of framework internal design changes on the mechanical properties of cobalt-chromium (Co-Cr) specimens manufactured by using direct metal laser sintering (DMLS). MATERIAL AND METHODS Dumbbell-shaped test specimens were designed as per the International Organization for Standardization (ISO) 22674(E) standard by using a 3-dimensional software program. A total of 70 dumbbell-shaped specimens were prepared by using Co-Cr alloy powder and DMLS (n=10). The control group specimens were solid with the internal completely filled. For the test groups, the internal design of the dumbbell-shaped specimens was modified. Leaving the outer shell thickness of the specimens at 0.5 mm for all test groups, 6 different internal designs were created, and the specimens were weighed. The tensile strength test was used to evaluate the mean peak strength, elastic modulus, and percentage elongation of the specimens. One-way ANOVA followed by the Dunnett T3 test was used for statistical analysis (α=.05). RESULTS A statistically significant difference was found among the groups in terms of bar weight and peak strength (P<.05). The highest values were observed in the control group for all evaluated parameters (mean ±standard deviation bar weight: 1321.3 ±36.6 mg, peak strength: 1045 ±36.7 MPa, elastic modulus: 284.2 ±71.9 GPa, and elongation: 28.7 ±7%). However, no statistically significant difference was observed for elastic modulus or percentage of elongation (P>.05). CONCLUSIONS Decreasing the weight of the frameworks by changing the internal design of the specimens also decreased the peak strength. However, it did not affect the elastic modulus or the percentage of elongation.
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Vichi A, Corciolani G, Carrabba M, Munoz A, Louca C. Influence of Thickness of Opaque Porcelain and Alloy Color on the Final Color of Porcelain-Fused-to-Metal Restorations. MATERIALS (BASEL, SWITZERLAND) 2023; 16:457. [PMID: 36614796 PMCID: PMC9821996 DOI: 10.3390/ma16010457] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 12/14/2022] [Accepted: 12/22/2022] [Indexed: 06/17/2023]
Abstract
Despite the advent of metal-free solutions, porcelain-fused-to-metal restorations (PFM) are still widely used. Particularly for the latest ceramic systems, scarce information is present in the scientific literature about the ideal opaque layer thickness and the alloy color impact to achieve the desired final color of PFM restorations. This study aimed to evaluate the influence of opaque thickness variation layered on different metal alloys on the final color of PFM restorations. Opaque porcelain of one metal−ceramic system (VITA VM13) was layered in four different thicknesses (0.10 mm, 0.15 mm, 0.20 mm, and 0.25 mm) on three differently colored dental alloys: a gold−platinum alloy (yellowish), a gold−palladium alloy (light grayish), and a nickel−chromium alloy (dark grayish). The veneering porcelain layered over the opaque was kept constant (Base Dentine 0.45 mm, Transpa Dentine 0.50 mm, and Enamel 0.20 mm). Sixty specimens were fabricated, five samples for each combination of alloy/opaque thickness. The color difference (ΔE) between specimen and reference was measured using a clinical spectrophotometer. The two-way ANOVA revealed that the thickness of both the opaque (p < 0.001) and the metal alloy (p < 0.001) significantly influenced the ΔE values. Gray-colored alloys covered by a 0.10 mm thick opaque layer enabled the closest color match, whereas this occurred for yellow-color alloys covered by a 0.15 mm thick opaque layer. In contrast, the samples covered by a 0.25 mm thick opaque layer obtained the worst ΔE.
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Affiliation(s)
- Alessandro Vichi
- Dental Academy, University of Portsmouth, Portsmouth PO1 2QG, UK
| | | | | | - Alvaro Munoz
- Faculty of Dentistry, University of Chile, Santiago 8380544, Chile
| | - Chris Louca
- Dental Academy, University of Portsmouth, Portsmouth PO1 2QG, UK
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Davoodi E, Montazerian H, Mirhakimi AS, Zhianmanesh M, Ibhadode O, Shahabad SI, Esmaeilizadeh R, Sarikhani E, Toorandaz S, Sarabi SA, Nasiri R, Zhu Y, Kadkhodapour J, Li B, Khademhosseini A, Toyserkani E. Additively manufactured metallic biomaterials. Bioact Mater 2022; 15:214-249. [PMID: 35386359 PMCID: PMC8941217 DOI: 10.1016/j.bioactmat.2021.12.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 12/17/2021] [Accepted: 12/21/2021] [Indexed: 02/06/2023] Open
Abstract
Metal additive manufacturing (AM) has led to an evolution in the design and fabrication of hard tissue substitutes, enabling personalized implants to address each patient's specific needs. In addition, internal pore architectures integrated within additively manufactured scaffolds, have provided an opportunity to further develop and engineer functional implants for better tissue integration, and long-term durability. In this review, the latest advances in different aspects of the design and manufacturing of additively manufactured metallic biomaterials are highlighted. After introducing metal AM processes, biocompatible metals adapted for integration with AM machines are presented. Then, we elaborate on the tools and approaches undertaken for the design of porous scaffold with engineered internal architecture including, topology optimization techniques, as well as unit cell patterns based on lattice networks, and triply periodic minimal surface. Here, the new possibilities brought by the functionally gradient porous structures to meet the conflicting scaffold design requirements are thoroughly discussed. Subsequently, the design constraints and physical characteristics of the additively manufactured constructs are reviewed in terms of input parameters such as design features and AM processing parameters. We assess the proposed applications of additively manufactured implants for regeneration of different tissue types and the efforts made towards their clinical translation. Finally, we conclude the review with the emerging directions and perspectives for further development of AM in the medical industry.
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Affiliation(s)
- Elham Davoodi
- Multi-Scale Additive Manufacturing (MSAM) Laboratory, Mechanical and Mechatronics Engineering Department, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- Department of Bioengineering, University of California, Los Angeles, California 90095, United States
- California NanoSystems Institute (CNSI), University of California, Los Angeles, California 90095, United States
- Terasaki Institute for Biomedical Innovation, Los Angeles, California 90024, United States
| | - Hossein Montazerian
- Department of Bioengineering, University of California, Los Angeles, California 90095, United States
- California NanoSystems Institute (CNSI), University of California, Los Angeles, California 90095, United States
- Terasaki Institute for Biomedical Innovation, Los Angeles, California 90024, United States
| | - Anooshe Sadat Mirhakimi
- Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, Isfahan 84156-83111, Iran
| | - Masoud Zhianmanesh
- School of Biomedical Engineering, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Osezua Ibhadode
- Multi-Scale Additive Manufacturing (MSAM) Laboratory, Mechanical and Mechatronics Engineering Department, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Shahriar Imani Shahabad
- Multi-Scale Additive Manufacturing (MSAM) Laboratory, Mechanical and Mechatronics Engineering Department, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Reza Esmaeilizadeh
- Multi-Scale Additive Manufacturing (MSAM) Laboratory, Mechanical and Mechatronics Engineering Department, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Einollah Sarikhani
- Department of Nanoengineering, Jacobs School of Engineering, University of California, San Diego, California 92093, United States
| | - Sahar Toorandaz
- Multi-Scale Additive Manufacturing (MSAM) Laboratory, Mechanical and Mechatronics Engineering Department, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Shima A. Sarabi
- Mechanical and Aerospace Engineering Department, University of California, Los Angeles, California 90095, United States
| | - Rohollah Nasiri
- Terasaki Institute for Biomedical Innovation, Los Angeles, California 90024, United States
| | - Yangzhi Zhu
- Terasaki Institute for Biomedical Innovation, Los Angeles, California 90024, United States
| | - Javad Kadkhodapour
- Department of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran, Tehran 16785-163, Iran
- Institute for Materials Testing, Materials Science and Strength of Materials, University of Stuttgart, Stuttgart 70569, Germany
| | - Bingbing Li
- Terasaki Institute for Biomedical Innovation, Los Angeles, California 90024, United States
- Department of Manufacturing Systems Engineering and Management, California State University, Northridge, California 91330, United States
| | - Ali Khademhosseini
- Terasaki Institute for Biomedical Innovation, Los Angeles, California 90024, United States
| | - Ehsan Toyserkani
- Multi-Scale Additive Manufacturing (MSAM) Laboratory, Mechanical and Mechatronics Engineering Department, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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Aydın N, Ekren O, Kocak EF, Ucar Y. Comparison of the Marginal and Internal Discrepancy of Metal-Ceramic Restorations Produced by Milling for Soft Metal, Direct Metal Laser Sintering and Casting Methods: An In Vitro Study. JOURNAL OF ADVANCED ORAL RESEARCH 2022. [DOI: 10.1177/23202068221103980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Aim: To evaluate the effect of ceramic firing cycles on the internal and marginal discrepancy of restorations fabricated using conventional lost wax casting (LW), direct metal laser sintering (DMLS), and milling for soft metal (MS). Materials and Methods: A total of 45 restorations were produced by LW, DMLS, and MS methods ( n = 15), according to the digital impression on the metal die representing the prepared first molar. The internal discrepancy (ID) was measured through the silicon weight method and the marginal discrepancy (MD) was measured using a light microscope. ID and MD measurements were repeated following the metal manufacturing, ceramic application, and glazing. Statistical analyses were conducted by means of two-way analysis of variance and Tukey-HSD ( α = 0.05) tests. Results: Statistically significant differences were found between the fabrication methods ( P ≤ 0.001) both for MD and ID. The mean MD values of the restorations were 31.4 ± 13.8 µm for MS, 20.8 ± 14.4 µm for LW, and 7.3 ± 6 µm for DMLS. A statistically significant increase was observed in the mean MD values of metal frameworks ( P ≤ 0.001) following ceramic and glaze applications. However, no statistically significant difference was found between the ceramic and the glaze applied stages ( P = .072). The mean ID values were 37 ± 5.7 mg for LW, 28 ± 6.1 mg for DMLS, and 21.6 ± 7.3 mg for MS. Unlike the manufacturing method, ceramic firing cycles had no effects on the ID ( P > 0.05). Conclusion: MS had the highest mean MD, but it had the lowest ID. The ceramic firing had a significantly negative effect only on MD.
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Affiliation(s)
- Nazlı Aydın
- Department of Prosthetic Dentistry, Faculty of Dentistry, Cukurova University, Balcali, Adana, Turkey
- Abdi Sutcu Vocational School of Health Services, Cukurova University, Balcali, Adana, Turkey
| | - Orhun Ekren
- Department of Prosthetic Dentistry, Faculty of Dentistry, Cukurova University, Balcali, Adana, Turkey
- Department of Advanced Materials and Nanotechnology, Institute of Natural and Applied Sciences, Cukurova University, Balcali, Adana, Turkey
| | - Elif Figen Kocak
- Department of Prosthetic Dentistry, Faculty of Dentistry, Cukurova University, Balcali, Adana, Turkey
- Abdi Sutcu Vocational School of Health Services, Cukurova University, Balcali, Adana, Turkey
| | - Yurdanur Ucar
- Private Dental Practice, Motto Oral and Dental Health Polyclinic, Antalya, Turkey
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Kaleli N, Ekren O, Uçar Y, Ural Ç. Evaluation of the flexural strength of metal frameworks fabricated by sintering-based computer-aided manufacturing methods. J Prosthet Dent 2022; 127:936.e1-936.e7. [DOI: 10.1016/j.prosdent.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 04/11/2022] [Accepted: 04/12/2022] [Indexed: 10/18/2022]
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Saleeva L, Kashapov R, Shakirzyanov F, Kuznetsov E, Kashapov L, Smirnova V, Kashapov N, Saleeva G, Sachenkov O, Saleev R. The Effect of Surface Processing on the Shear Strength of Cobalt-Chromium Dental Alloy and Ceramics. MATERIALS 2022; 15:ma15092987. [PMID: 35591320 PMCID: PMC9103724 DOI: 10.3390/ma15092987] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/12/2022] [Accepted: 04/14/2022] [Indexed: 02/05/2023]
Abstract
Porcelain fused to metal is widespread dental prosthetic restoration. The survival rate of metal-ceramic restorations depends not only on the qualifications of dentists, dental technicians but also on the adhesive strength of ceramics to a metal frame. The goal of the research is to determine the optimal parameters of the surface machining of the metal frame to increase the adhesion of metal to ceramics. Adhesion of cobalt-chromium alloy and ceramics was investigated. A profilometer and a scanning electron microscope were used to analyze the morphology. To estimate the adhesion the shear strength was measured by the method based on ASTM D1002-10. A method of surface microrelief formation of metal samples by plasma-electrolyte treatment has been developed. Regimes for plasma-electrolyte surface treatment were investigated according to current-voltage characteristics and a surface roughness parameter. The samples were subjected to different surface machining techniques such as polishing, milling, sandblasting (so-called traditional methods), and plasma-electrolyte processing. Morphology of the surface for all samples was studied and the difference in microrelief was shown. The roughness and adhesive strength were measured for samples either. As a result, the mode for plasma- electrolytic surface treatment under which the adhesive strength was increased up to 183% (compared with the traditional methods) was found.
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Affiliation(s)
- Liaisan Saleeva
- Kazan State Medical University, 420012 Kazan, Russia; (L.S.); (E.K.); (G.S.); (R.S.)
| | - Ramil Kashapov
- Joint Institute for High Temperatures of the Russian Academy of Science, 125412 Moscow, Russia; (R.K.); (L.K.); (N.K.)
- Institute of Engineering, Kazan Federal University, 420008 Kazan, Russia
| | - Farid Shakirzyanov
- Kazan State University of Architecture and Engineering, 420043 Kazan, Russia;
| | - Eduard Kuznetsov
- Kazan State Medical University, 420012 Kazan, Russia; (L.S.); (E.K.); (G.S.); (R.S.)
| | - Lenar Kashapov
- Joint Institute for High Temperatures of the Russian Academy of Science, 125412 Moscow, Russia; (R.K.); (L.K.); (N.K.)
- Institute of Engineering, Kazan Federal University, 420008 Kazan, Russia
| | - Viktoriya Smirnova
- N.I. Lobachevsky Institute of Mathematics, Kazan Federal University, 420008 Kazan, Russia;
| | - Nail Kashapov
- Joint Institute for High Temperatures of the Russian Academy of Science, 125412 Moscow, Russia; (R.K.); (L.K.); (N.K.)
- Institute of Engineering, Kazan Federal University, 420008 Kazan, Russia
| | - Gulshat Saleeva
- Kazan State Medical University, 420012 Kazan, Russia; (L.S.); (E.K.); (G.S.); (R.S.)
| | - Oskar Sachenkov
- N.I. Lobachevsky Institute of Mathematics, Kazan Federal University, 420008 Kazan, Russia;
- Correspondence:
| | - Rinat Saleev
- Kazan State Medical University, 420012 Kazan, Russia; (L.S.); (E.K.); (G.S.); (R.S.)
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Air quality in a hospital dental department. J Dent Sci 2022; 17:1350-1355. [PMID: 35784142 PMCID: PMC9236934 DOI: 10.1016/j.jds.2022.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 03/23/2022] [Indexed: 11/24/2022] Open
Abstract
Background/purpose Documented studies demonstrated that particulate matter 2.5 (PM2.5) are relatively high in dental clinics. However, the PM2.5 composition is unclear. This study aimed to evaluate the dental department's air quality in a teaching hospital. Materials and methods The SKC AirChek XR5000 pumps and canister samplers were used to collect PM2.5 and volatile organic compounds (VOCs). The PM2.5 composition analysis (polycyclic aromatic hydrocarbons (PAHs) and metals) was conducted, and in the dental clinic and waiting room, the air quality comparison was investigated. Moreover, the dental clinic's air quality was compared before and after air purifier use. Results In the dental clinic and waiting room, the results revealed high PM2.5 concentration exceeding the standard of the United States Environmental Protection Agency (USEPA) (35 μg/m3); the values were 41.08–108.23 μg/m3 and 17.89–62.72 μg/m3, respectively. In both investigated locations, VOCs had no significant difference. Among 16 priority PAHs, the result indicated high level of benzo(b)fluoranthene (B(b)f), benzo(k)fluoranthene (B(k)f), benzo(a)pyrene (B(a)p), and indenopyrene (IP). B(b)f and B(k)f and lead (Pb) concentrations were detected with a significant difference in the clinic as compared to the waiting room. In addition, after air purifier use, the B(b)f concentration in the dental clinic reduced from 0.08 to 0.42 ug/m3 to 0.06–0.18 ug/m3 (P < 0.05). Conclusion For dental practitioners, an appropriated air quality regulation needs to be considered, due to high air pollutant concentration. In addition, using air purifier can efficiently reduce air pollutants.
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Corrosive Studies of a Prosthetic Ni-Cr Alloy Coated with Ti(C,N) Type Layers. MATERIALS 2022; 15:ma15072471. [PMID: 35407804 PMCID: PMC8999788 DOI: 10.3390/ma15072471] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 03/15/2022] [Accepted: 03/21/2022] [Indexed: 02/04/2023]
Abstract
Background: Investigating the general corrosion resistance of Ti(C,N) type coatings on a prosthetic nickel alloy in the aspect of their use as protective coatings on prosthetic and orthodontic elements. Methods: Five groups of Ni-Cr alloy samples covered with Ti(C,N) type coatings differing in their carbon and nitrogen contents were used for the tests. The reference group included alloy samples without coatings. The samples were held for 105 days (2520 h) in salt spray chambers and examined by means of the NSS (neutral salt spray) and SWAAT (sea water acetic acid test) tests. After the periods of 14, 28, 81 and 105 days, the samples were removed and weighed, and their weight losses were determined. Results: In the case of each type of Ti(C,N) coating, the mass loss was lower than the mass loss of a sample without a coating, which makes it possible to state that coatings improve the corrosion resistance. No significant differences in the resistance were observed between the particular coatings. The corrosion rate of the examined coatings is close to parabolic. Conclusions: Ti(C,N) type coatings improve the resistance of a prosthetic Ni-Cr alloy and can be used as protective coatings for prosthetic and orthodontic elements.
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Lim J, Bae EJ, Kim JH. Evaluation of internal fit of press ceramic and porous structured cobalt–chromium crown fabricated by additive manufacturing. Dent Res J (Isfahan) 2022. [DOI: 10.4103/1735-3327.353834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Garcia-Falcon CM, Gil-Lopez T, Verdu-Vazquez A, Mirza-Rosca JC. Analysis and Comparison of the Corrosive Behavior of Nickel-Based and Cobalt-Based Dental Alloys. MATERIALS (BASEL, SWITZERLAND) 2021; 14:4949. [PMID: 34501039 PMCID: PMC8434020 DOI: 10.3390/ma14174949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/22/2021] [Accepted: 08/23/2021] [Indexed: 11/23/2022]
Abstract
Nickel-based and cobalt-based metal alloys are frequently used in dentistry. The introduction of various elements in the alloy changes its characteristics, and a thorough study of each alloy should be completed to determine its appropriate corrosion resistance and biocompatibility in contact with physiological fluids. There are scarce investigations on these widely used dental alloys in Ringer solution, and findings in this research bring new experimental data and information. The present study evaluated and compared the corrosion behavior of six NiCr- and two CoCr-based dental materials in Ringer solution, using the following techniques: potentiostatic polarization curves (chronoamperometry), microstructural analysis, and EIS (electrochemical impedance spectroscopy). The results obtained in this investigation showed that in the NiCr-based specimens Ni4, Ni5, and Ni6 the stability of the passive layer was destroyed after polarization and a development and growth of stable pits was found in the microstructural analysis after electrochemical treatment. In terms of susceptibility to corrosion, two different groups of specimens were derived from this investigation. A first group which included the two CoCr (Co1 and Co2) and three of the six NiCr alloys studied (Ni1, Ni2, and Ni3). A second group with the other NiCr alloys investigated Ni4, Ni5, and Ni6.
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Affiliation(s)
- Carmen Marina Garcia-Falcon
- Nanoscience and Nanomaterials, Department of Mechanical Engineering, University of Las Palmas de Gran Canaria, 35017 Las Palmas, Spain; (C.M.G.-F.); (J.C.M.-R.)
| | - Tomas Gil-Lopez
- Science and Engineering, Department of Building Technology, Madrid Polytechnic University, 28040 Madrid, Spain;
| | - Amparo Verdu-Vazquez
- Science and Engineering, Department of Building Technology, Madrid Polytechnic University, 28040 Madrid, Spain;
| | - Julia Claudia Mirza-Rosca
- Nanoscience and Nanomaterials, Department of Mechanical Engineering, University of Las Palmas de Gran Canaria, 35017 Las Palmas, Spain; (C.M.G.-F.); (J.C.M.-R.)
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Revilla-León M, Gómez-Polo M, Park SH, Barmak BA, Özcan M. Adhesion of veneering porcelain to cobalt-chromium dental alloys processed with casting, milling, and additive manufacturing methods: A systematic review and meta-analysis. J Prosthet Dent 2021; 128:575-588. [PMID: 34294418 DOI: 10.1016/j.prosdent.2021.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 01/13/2021] [Accepted: 01/13/2021] [Indexed: 01/19/2023]
Abstract
STATEMENT OF PROBLEM Selective laser melting (SLM) additive manufacturing (AM) technologies provide an alternative to conventional casting and milling procedures in fabricating metal-ceramic dental prostheses. However, the quality of porcelain bond strength to the SLM AM cobalt-chromium (Co-Cr) metal framework of a dental restoration is unclear. PURPOSE The purpose of this systematic review and meta-analysis was to identify in vitro studies that reported the porcelain bond strength to SLM AM Co-Cr dental metal alloys and compare the porcelain bond strength values to cast, milled, and additively manufactured Co-Cr dental alloys. MATERIAL AND METHODS An electronic systematic review was performed in different databases: MEDLINE/PubMed, EMBASE, World of Science, Cochrane, and Scopus. A manual search was also conducted. Studies that reported the porcelain bond strength to SLM Co-Cr metal alloys and in the English language were included. Two investigators evaluated the quality assessment of the studies by applying the JBI critical appraisal checklist for quasi-experimental studies (nonrandomized experimental studies). A third investigator was consulted to resolve lack of consensus. Two subgroups were created based on the test used, 3-point bend and shear bond strength tests. The porcelain bond strength of cast, milled, and AM Co-Cr dental alloys were compared. The I2 statistic and its associated P value were used to assess the heterogeneity between studies. The Eger test was used for determining significance of the funnel pots. RESULTS A total of 216 studies were collected from the electronic and manual searches. After independently evaluating the titles and abstracts by the reviewers, 26 articles were identified. Three of these were excluded after full-text revision. The porcelain bond strength comparison between the cast and AM alloys for the 3-point bend subgroup revealed a significant result for overall effect (P<.001) favoring the SLM method with considerable heterogeneity (I2=83%, P<.001). Furthermore, the porcelain bond strength comparison between cast and milled alloys for the shear bond strength subgroup revealed a significant test for overall effect (P=.04) favoring milled procedures with a nonsignificant unimportant heterogeneity (I2= 0%, P<.47) and for the 3-point bend subgroup (P<.001) favoring milled specimens with a significant considerable heterogeneity (I2=79%, P<.001). CONCLUSIONS The metal manufacturing method had no effect on the porcelain bond strength to Co-Cr dental metal alloys.
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Affiliation(s)
- Marta Revilla-León
- Assistant Professor and Assistant Program Director AEGD Residency, Comprehensive Dentistry Department, College of Dentistry, Texas A&M University, Dallas, Texas; Affiliate Faculty Graduate Prosthodontics, Department of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, Wash; Researcher at Revilla Research Center, Madrid, Spain
| | - Miguel Gómez-Polo
- Associate Professor Department of Conservative Dentistry and Prosthodontics, School of Dentistry, Complutense University of Madrid, Madrid, Spain.
| | | | - Basir A Barmak
- Assistant Professor Clinical Research and Biostatistics, Eastman Institute of Oral Health, University of Rochester Medical Center, Rochester, N.Y
| | - Mutlu Özcan
- Professor and Head, Division of Dental Biomaterials, Clinic for Reconstructive Dentistry, Center for Dental and Oral Medicine, University of Zürich, Zurich, Switzerland
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Cantó-Navés O, Medina-Galvez R, Marimon X, Ferrer M, Figueras-Álvarez Ó, Cabratosa-Termes J. A 3D Finite Element Analysis Model of Single Implant-Supported Prosthesis under Dynamic Impact Loading for Evaluation of Stress in the Crown, Abutment and Cortical Bone Using Different Rehabilitation Materials. MATERIALS (BASEL, SWITZERLAND) 2021; 14:3519. [PMID: 34202625 PMCID: PMC8269525 DOI: 10.3390/ma14133519] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 06/13/2021] [Accepted: 06/18/2021] [Indexed: 12/19/2022]
Abstract
In the literature, many researchers investigated static loading effects on an implant. However, dynamic loading under impact loading has not been investigated formally using numerical methods. This study aims to evaluate, with 3D finite element analysis (3D FEA), the stress transferred (maximum peak and variation in time) from a dynamic impact force applied to a single implant-supported prosthesis made from different materials. A 3D implant-supported prosthesis model was created on a digital model of a mandible section using CAD and reverse engineering. By setting different mechanical properties, six implant-supported prostheses made from different materials were simulated: metal (MET), metal-ceramic (MCER), metal-composite (MCOM), carbon fiber-composite (FCOM), PEEK-composite (PKCOM), and carbon fiber-ceramic (FCCER). Three-dimensional FEA was conducted to simulate the collision of 8.62 g implant-supported prosthesis models with a rigid plate at a speed of 1 m/s after a displacement of 0.01 mm. The stress peak transferred to the crown, titanium abutment, and cortical bone, and the stress variation in time, were assessed.
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Affiliation(s)
- Oriol Cantó-Navés
- Faculty of Dentistry, Universitat Internacional de Catalunya (UIC), 08017 Barcelona, Spain; (O.C.-N.); (R.M.-G.); (Ó.F.-Á.); (J.C.-T.)
| | - Raul Medina-Galvez
- Faculty of Dentistry, Universitat Internacional de Catalunya (UIC), 08017 Barcelona, Spain; (O.C.-N.); (R.M.-G.); (Ó.F.-Á.); (J.C.-T.)
| | - Xavier Marimon
- Bioengineering Institute of Technology, Universitat Internacional de Catalunya (UIC), 08190 Barcelona, Spain
- Automatic Control Department, Universitat Politècnica de Catalunya (UPC-BarcelonaTECH), 08034 Barcelona, Spain
| | - Miquel Ferrer
- Department of Strength of Materials and Structural Engineering, Universitat Politècnica de Catalunya (UPC-BarcelonaTECH), 08034 Barcelona, Spain;
| | - Óscar Figueras-Álvarez
- Faculty of Dentistry, Universitat Internacional de Catalunya (UIC), 08017 Barcelona, Spain; (O.C.-N.); (R.M.-G.); (Ó.F.-Á.); (J.C.-T.)
| | - Josep Cabratosa-Termes
- Faculty of Dentistry, Universitat Internacional de Catalunya (UIC), 08017 Barcelona, Spain; (O.C.-N.); (R.M.-G.); (Ó.F.-Á.); (J.C.-T.)
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Fracture Load of CAD/CAM Fabricated Cantilever Implant-Supported Zirconia Framework: An In Vitro Study. Molecules 2021; 26:molecules26082259. [PMID: 33924733 PMCID: PMC8069778 DOI: 10.3390/molecules26082259] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 11/17/2022] Open
Abstract
The fracture resistance of computer-aided designing and computer-aided manufacturing CAD/CAM fabricated implant-supported cantilever zirconia frameworks (ISCZFs) is affected by the size/dimension and the micro cracks produced from diamond burs during the milling process. The present in vitro study investigated the fracture load for different cross-sectional dimensions of connector sites of implant-supported cantilever zirconia frameworks (ISCZFs) with different cantilever lengths (load point). A total of 48 ISCZFs (Cercon, Degudent; Dentsply, Deutschland, Germany) were fabricated by CAD/CAM and divided into four groups based on cantilever length and reinforcement of distal-abutment: Group A: 9 mm cantilever; Group B: 9 mm cantilever with reinforced distal-abutment; Group C: 12 mm cantilever; Group D: 12 mm cantilever with reinforced distal-abutment (n = 12). The ISCZFs were loaded using a universal testing machine for recording the fracture load. Descriptive statistics, ANOVA, and Tukey's test were used for the statistical analysis (p < 0.05). Significant variations were found between the fracture loads of the four ISCZFs (p = 0.000); Group-C and B were found with the weakest and the strongest distal cantilever frameworks with fracture load of 670.39 ± 130.96 N and 1137.86 ± 127.85 N, respectively. The mean difference of the fracture load between groups A (810.49 + 137.579 N) and B (1137.86 ± 127.85 N) and between C (670.39 ± 130.96 N) and D (914.58 + 149.635 N) was statistically significant (p = 0.000). Significant variations in the fracture load between the ISCZFs with different cantilever lengths and thicknesses of the distal abutments were found. Increasing the thickness of the distal abutment only by 0.5 mm reinforces the distal abutments by significantly increasing the fracture load of the ISCZFs. Therefore, an increase in the thickness of the distal abutments is recommended in patients seeking implant-supported distal cantilever fixed prostheses.
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Kaleli N, Uçar Y, Ekren O, Ural Ç. Effect of layer thickness on the flexural strength of multiple-unit laser-sintered metal frameworks. J Prosthet Dent 2021; 127:651-658. [PMID: 33640087 DOI: 10.1016/j.prosdent.2020.10.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/05/2020] [Accepted: 10/05/2020] [Indexed: 11/29/2022]
Abstract
STATEMENT OF PROBLEM Laser sintering devices have been increasingly used to fabricate the metal frameworks of metal-ceramic restorations. In the fabrication process, the sintering layer thickness is an important parameter; however, information on how it may affect the flexural strength of metal frameworks remains limited. PURPOSE The purpose of this in vitro study was to evaluate the flexural strength of 3-unit and 4-unit cobalt-chromium (Co-Cr) metal frameworks laser sintered with 20-μm, 30-μm, and 40-μm layer thicknesses. MATERIAL AND METHODS Three-unit and 4-unit master metal die models with premolar and molar abutments were prepared through direct metal laser sintering (DMLS). A total of 40 metal frameworks (n=10 for each metal die model) were fabricated by the lost-wax technique (group C, served as the control group) and through DMLS with 20-μm, 30-μm, and 40-μm layer thickness (experimental groups LS20, LS30, and LS40, respectively). Each metal framework was cemented to a master die with a polyvinyl siloxane impression material and then subjected to a 3-point bend test at a crosshead speed of 1 mm/min. The yield force of each metal framework was used to calculate the flexural strength. Data were statistically analyzed by using 1-way ANOVA followed by a Tukey honestly significant difference (HSD) test and an independent-samples t test (α=.05) The microstructure of the fracture surface was evaluated by scanning electron microscopy. RESULTS Group C reported the lowest mean flexural strength (P<.05), whereas group LS20 reported the highest mean flexural strength, although no significant difference (P>.05) in flexural strength was observed among the DMLS groups. The 3-unit metal frameworks exhibited a statistically significant higher mean flexural strength than the 4-unit metal frameworks (P<.05). CONCLUSIONS The sintering layer thickness did not significantly affect the flexural strength of the laser-sintered metal frameworks. However, the DMLS groups reported a higher mean flexural strength than the cast group.
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Affiliation(s)
- Necati Kaleli
- Assistant Professor, Department of Dentistry Services, Vocational School of Health Services, Ondokuz Mayıs University, Samsun, Turkey.
| | - Yurdanur Uçar
- Professor, Department of Prosthodontics, Faculty of Dentistry, Çukurova University, Adana, Turkey
| | - Orhun Ekren
- Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Çukurova University, Adana, Turkey
| | - Çağrı Ural
- Professor, Department of Prosthodontics, Faculty of Dentistry, Ondokuz University, Samsun, Turkey
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In-Situ XRD Study of Phase Transformation Kinetics in a Co-Cr-W-Alloy Manufactured by Laser Powder-Bed Fusion. CRYSTALS 2021. [DOI: 10.3390/cryst11020176] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The additive manufacturing process of laser powder-bed fusion (L-PBF) is an increasingly popular approach for patient-specific production of dental frameworks made from Co-Cr alloys. Macroscopically, frameworks produced in this way exhibit high anisotropy especially in Young’s modulus, and are missing standardized requirements. Microscopically, pronounced texture and high residual stresses are characteristic. To reduce resulting detrimental effects, the as-built (AB) parts are heat treated. Dependent on the treatment temperature, effects like the transformation of the γ-phase matrix in the AB condition to ϵ-phase, precipitation, stress relief, and grain growth were observed. While the existence of these processes was established in the past, little is known about their kinetics. To fill this gap, these effects were studied with in-situ X-ray diffraction (XRD) methods in isothermal heat treatments (HTs) at four different sample surface temperatures TS reaching from 650∘C to 900∘C. Furthermore, room temperature ex situ XRD and SEM/EDS measurements completed the analysis. An evaluation of the datasets, with single peak fitting and QXRD methods, yielded the following results. In the HTs below a certain threshold, a γ-to-ϵ transformation was observed in the sample bulk and close to the sample surface. In the latter case, evidence for a partially strain-induced transformation related to oxide formation was present. Above this threshold and possibly slightly below, σ- and Laves-phase precipitated. Additionally, peak profile evolutions hinted at a drop of inter- and intragranular stresses within the first 30 to 60 min. Therefore, an HT of about 30 to 60 min slightly above the threshold is proposed as optimal for reducing residual stresses while retaining a predominantly single-phased microstructure, possibly superior in corrosion properties and likewise in bio-compatibility.
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Mechanical Properties and Metal-Ceramic Bond Strength of Co-Cr Alloy Manufactured by Selective Laser Melting. MATERIALS 2020; 13:ma13245745. [PMID: 33339320 PMCID: PMC7766189 DOI: 10.3390/ma13245745] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 12/08/2020] [Accepted: 12/14/2020] [Indexed: 01/04/2023]
Abstract
Cobalt–chromium (Co-Cr) metal is one of the widely used biomaterials in the fabrication of dental prosthesis. The purpose of this study was to investigate whether there are differences in the properties of metals and bond strength with ceramics depending on the manufacturing methods of Co-Cr alloy. Co-Cr alloy specimens were prepared in three different ways: casting, milling, and selective laser melting (SLM). The mechanical properties (elastic modulus, yield strength, and flexural strength) of the alloys were investigated by flexure method in three-point bending mode, and microstructures of the specimens were analyzed. After application of the veneering ceramic through the three-point bending test, bond strength of the Metal-Ceramic was investigated. The cracked surfaces were observed by means of energy dispersive X-ray (EDX) spectroscopy and scanning electron microscopy (SEM) with backscattered electron (BSE) images. In mechanical properties, the elastic modulus was highest for the casting group, and the yield strength and flexural strength were lowest for the milling group. The SLM group showed finer homogeneous crystalline-microstructure, and a layered structure was observed at the fractured surface. After the ceramic bond strength test, all groups showed a mixed failure pattern. The casting group showed the highest bond strengths, whereas there was no significant difference between the other two groups. However, all groups have met the standard of bond strength according to international standards organization (ISO) with the appropriate passing rate. The results of this study indicate that the SLM manufacturing method may have the potential to replace traditional techniques for fabricating dental prosthesis.
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Hong MH, Lee DH, Hanawa T, Kwon TY. Comparison of microstructures and mechanical properties of 3 cobalt-chromium alloys fabricated with soft metal milling technology. J Prosthet Dent 2020; 127:489-496. [PMID: 33303192 DOI: 10.1016/j.prosdent.2020.07.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 07/25/2020] [Accepted: 07/27/2020] [Indexed: 10/22/2022]
Abstract
STATEMENT OF PROBLEM Although several manufacturers market soft metal milling blanks and systems, comprehensive comparative studies of differences in properties across commercially available soft metal milling alloys are lacking. PURPOSE The purpose of this in vitro study was to compare the microstructures and mechanical properties of 3 soft metal milling cobalt-chromium (Co-Cr) alloys (Ceramill Sintron, Soft Metal, and Sintermetall). MATERIAL AND METHODS Disk-shaped specimens (for surface characterization and hardness test) and dumbbell-shaped specimens (for tensile test as per International Organization for Standardization (ISO) 22674) were prepared by following each soft metal milling manufacturer's instructions. The crystal structures and microstructures of the 3 alloys were evaluated with optical microscopy, X-ray diffractometry (XRD), and scanning electron microscopy with electron backscattered diffraction (EBSD). The mechanical properties were investigated with a tensile test and Vickers hardness test (n=6). The results of the mechanical (tensile and hardness) tests were analyzed with 1-way ANOVA and the post hoc Tukey multiple comparison test (α=.05). RESULTS The Sintermetall specimen showed a finer microstructure and more porosity than the other 2 alloys. The XRD and EBSD analyses showed that the γ (face-centered cubic, fcc) matrix phase was predominant in the Ceramill Sintron alloy and the ε (hexagonal close-packed, hcp) matrix phase was predominant in the Soft Metal alloy. The Sintermetall alloy showed a slightly higher amount of ε phase than γ phase, with more chromium carbide formation than the other 2 alloys. The Ceramill Sintron alloy showed a significantly higher tensile strength than the other 2 alloys (P<.05), but a significantly lower 2% offset yield strength than the other 2 alloys (P<.05). The highest elongation was found in the Ceramill Sintron alloy, followed by the Sintermetall and Soft Metal alloys. The elastic modulus was the highest in the Sintermetall alloy, followed by the Soft Metal and Ceramill Sintron alloys. No significant differences in Vickers hardness values were detected among the 3 alloys (P=.263). CONCLUSIONS The different commercially available soft metal milling blanks and systems produced dissimilar alloys in terms of crystal structures and microstructures and, as a result, different mechanical properties.
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Affiliation(s)
- Min-Ho Hong
- Assistant Professor, Department of Dental Laboratory Science, College of Health Sciences, Catholic University of Pusan, Busan, Republic of Korea
| | - Du-Hyeong Lee
- Associate Professor, Department of Prosthodontics, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Takao Hanawa
- Professor, Department of Metallic Materials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tae-Yub Kwon
- Professor, Department of Dental Biomaterials, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea.
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Mechanical Properties of Laser-Sintered 3D-Printed Cobalt Chromium and Soft-Milled Cobalt Chromium. PROSTHESIS 2020. [DOI: 10.3390/prosthesis2040028] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Purpose: To compare the mechanical properties and fracture behaviour of laser-sintered/3D-printed cobalt chromium (LS CoCr) with soft-milled cobalt chromium (SM CoCr) to assess their suitability for use in high-stress areas in the oral cavity. Material and Method: Two computer-aided manufacturing methods were used to fabricate dumbbell specimens in accordance with the ASTM standard E8. Specimens were fractured using tensile testing and elastic modulus, and proof stress and ultimate tensile strength were calculated. Fracture surfaces were examined using scanning electron microscopy. Plate specimens were also fabricated for the examination of hardness and elastic modulus using nanoindentation. Unpaired t-test was used to evaluate statistical significance. Results: LS CoCr specimens were found to have significantly higher ultimate tensile strength (UTS) and proof stress (PS) (p < 0.05) but not a significantly higher elastic modulus (p > 0.05). Examination of the dumbbell fracture surfaces showed uniform structure for the LS CoCr specimens whilst the SM CoCr specimens were perforated with porosities; neither showed an obvious point of fracture. Nanoindentation also showed that LS CoCr specimens possessed higher hardness compared with SM CoCr specimens. Conclusion: LS CoCr and SM CoCr specimens were both found to exhibit uniformly dense structure; although porosities were noted in the SM CoCr specimens. LS CoCr specimens were found to have superior tensile properties, likely due to lack of porosities, however both had mean values higher than those reported in the literature for cast CoCr. Uniformity of structure and high tensile strength indicates that LS CoCr and SM CoCr fabricated alloys are suitable for long-span metallic frameworks for use in the field of prosthodontics.
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KALELİ N, URAL Ç, KÜÇÜKEKENCİ AS. Lazer Tarama Hızının Lazer Sinterleme ile Üretilen Metal Altyapıların Porselen Bağlantısı Üzerindeki Etkisi. KOCAELI ÜNIVERSITESI SAĞLIK BILIMLERI DERGISI 2020. [DOI: 10.30934/kusbed.636713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Kaleli N, Ural Ç, Us YÖ. Evaluation of marginal discrepancy in metal frameworks fabricated by sintering-based computer-aided manufacturing methods. J Adv Prosthodont 2020; 12:124-130. [PMID: 32601531 PMCID: PMC7314629 DOI: 10.4047/jap.2020.12.3.124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 03/20/2020] [Accepted: 04/01/2020] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The aim of this in vitro study was to evaluate the effect of sintering procedures on marginal discrepancies of fixed partial metal frameworks fabricated using different sintering-based computer-aided design and computer/aided manufacturing (CAD/CAM) techniques. MATERIALS AND METHODS Forty resin die models of prepared premolar and molar abutment teeth were fabricated using a three-dimensional (3D) printer and divided into four groups (n = 10) according to the fabrication method of metal frameworks used: HM (via hard milling), SM (via soft metal milling), L25 (via direct metal laser melting [DMLM] with a 25 µm layer thickness), and L50 (via direct DMLM with a 50 µm layer thickness). After the metal frameworks were fabricated and cemented, five vertical marginal discrepancy measurements were recorded in each site (i.e., buccal, facing the pontic, lingual, and facing away from the pontic) of both abutment teeth under a stereomicroscope (×40). Data were statistically analyzed at a significance level of 0.05. RESULTS No statistically significant differences (P>.05) were found among the four axial sites of metal frameworks fabricated by sintering-based CAD/CAM techniques. The HM and L25 groups showed significantly (P<.001) lower marginal discrepancy values than the SM and L50 groups. CONCLUSION Marginal discrepancy in the sites facing the pontic was not influenced by the type of sintering procedure. All fabrication methods exhibited clinically acceptable results in terms of marginal discrepancies.
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Affiliation(s)
- Necati Kaleli
- Department of Dentistry Services, Vocational School of Health Services, Ondokuz Mayıs University, Samsun, Turkey
| | - Çağrı Ural
- Department of Prosthodontics, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey
| | - Yeşim Ölçer Us
- Department of Prosthodontics, School of Dental Medicine, Bahçeşehir University, İstanbul, Turkey
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Haugli KH, Syverud M, Samuelsen JT. Ion release from three different dental alloys - effect of dynamic loading and toxicity of released elements. Biomater Investig Dent 2020; 7:71-79. [PMID: 32490402 PMCID: PMC7241566 DOI: 10.1080/26415275.2020.1747471] [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: 11/08/2019] [Accepted: 03/12/2020] [Indexed: 11/04/2022] Open
Abstract
Objective The aims of this in vitro study were to assess if dynamic loading increases the metal ion release of selected dental alloys and to evaluate the cytotoxicity of the released metal ions. Materials and methods One Pd–Ag alloy (Aurolite 2B) and two Co–Cr alloys (Wirobond 280 and d.Sign 30) were investigated. Two different corrosion immersion tests were used: a standardized static test (ISO 22674: 2016) and an experimental dynamic test. Both tests involved immersion of the specimens in a lactic acidic solution (pH = 2.3). Inductively coupled plasma mass spectrometry was used to identify and quantify released elements. A human monocyte cell-line (THP-1) was exposed to serially diluted solutions containing the selected metal ions. Cell viability was measured using the methyl-thiazolyl-tetrazolium assay. Results According to the threshold defined in ISO 22674, only low concentrations of released elements were observed for both corrosion tests. No increase in metal ion release from the dynamic test compared with the static test was observed. Of the released elements, only Zn(II) and Co(II) showed a cytotoxic effect on THP-1 cells at 250 µM and higher concentrations. No increased viability loss was observed when adding other released elements to the exposure mixture. Conclusions The tested alloys showed low levels of metal ion release from both static and dynamic corrosion testing. Dynamic loading did not increase the metal ion release compared to the static corrosion test. Concentrations of 250 µM and above of Zn(II) and Co(II) showed a cytotoxic effect on THP-1 cells.
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Affiliation(s)
| | - Morten Syverud
- Nordic Institute of Dental Materials (NIOM), Oslo, Norway
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Revilla-León M, Al-Haj Husain N, Methani MM, Özcan M. Chemical composition, surface roughness, and ceramic bond strength of additively manufactured cobalt-chromium dental alloys. J Prosthet Dent 2020; 125:825-831. [PMID: 32466963 DOI: 10.1016/j.prosdent.2020.03.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 03/10/2020] [Accepted: 03/10/2020] [Indexed: 10/24/2022]
Abstract
STATEMENT OF PROBLEM Selective laser melting (SLM) additive manufacturing (AM) technology is a current option to fabricate cobalt-chromium (Co-Cr) metal frameworks for dental prostheses. However, the Co-Cr alloy composition, surface roughness, and ceramic bond strength values that SLM metals can obtain are not well-defined. PURPOSE The purpose of this in vitro study was to compare the chemical composition, surface roughness, and ceramic shear bond strength of the milled and SLM Co-Cr dental alloys. MATERIAL AND METHODS A total of 50 disks of 5 mm in diameter and 1 mm in thickness were fabricated by using subtractive (control group) and AM with each of following SLM providers: SLM-1 (EOS), SLM-2 (3D systems), and SLM-3 (Concept Laser). The milled disks were airborne-particle abraded with 100-μm aluminum oxide particles. All the specimens were cleaned before surface roughness (Ra), weight (Wt%), and atomic (At%) percentages were analyzed. Three-dimensional profilometry was used to analyze the topographical properties of the surface parameters Ra (mean surface roughness). The chemical composition of Co-Cr alloy specimens was determined by using energy dispersive X-ray (EDAX) elemental analysis in a scanning electron microscope (SEM). Thereafter, the specimens were bonded to a ceramic (Dentine A3 and Enamel S-59; Creation CC) interface. Specimens were stored for 24 hours at 23 °C. The bond strength of the SLM-ceramic interface was measured by using the macroshear test (SBT) method (n=10). Adhesion tests were performed in a universal testing machine (1 mm/min). The Shapiro-Wilk test revealed that the chemical composition data were not normally distributed. Therefore, the atomic (At%) and weight percentages (Wt%) were analyzed by using the Kruskal-Wallis test, followed by pairwise Mann-Whitney U tests between the control and AM groups (AM-1 to AM-4). However, the Shapiro-Wilk test revealed that the surface roughness (Ra) and ceramic bond strength data were normally distributed. Therefore, data were analyzed by using 1-way ANOVA, followed by the post hoc Sidak test (α=.05). RESULTS Significant differences were obtained in Wt%, At%, and Ra values among the Co-Cr alloys evaluated (P<.05). Furthermore, the control group revealed significantly lower mean ±standard deviation Ra values (0.79 ±0.11 μm), followed by AM-3 (1.57 ±0.15 μm), AM-2 (1.80 ±0.43 μm), AM-1 (2.43 ±0.34 μm), and AM-4 (2.84 ±0.27 μm). However, no significant differences were obtained in the metal-ceramic shear bond strength among the different groups evaluated, ranging from mean ±standard deviation 75.77 ±11.92 MPa to 83.65 ±12.21 MPa. CONCLUSIONS Co-Cr dental alloys demonstrated a significant difference in their chemical compositions. Subtractive and additive manufacturing procedures demonstrated a significant influence on the surface roughness of the Co-Cr alloy specimens. However, the metal-ceramic shear bond strength of Co-Cr alloys was found to be independent of the manufacturing process.
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Affiliation(s)
- Marta Revilla-León
- Assistant Professor and Assistant Program Director AEGD, College of Dentistry, Texas A&M University, Dallas, Texas; Affiliate Faculty, Graduate Prosthodontics, University of Washington, Seattle, Wash; Researcher at Revilla Research Center, Madrid, Spain.
| | - Nadin Al-Haj Husain
- Specialization Candidate, Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland
| | - Mohammed Mujtaba Methani
- Student Master of Science in Oral Biology, College of Dentistry, Texas A&M University, Dallas, Texas
| | - Mutlu Özcan
- Professor and Head, Division of Dental Biomaterials, Clinic for Reconstructive Dentistry, University of Zürich, Zürich, Switzerland
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Shin HJ, Kwon YH, Seol HJ. Effect of cooling rate on hardness and microstructure of Pd-Ag-In-Sn-Ga alloy during porcelain firing simulation. J Mech Behav Biomed Mater 2020; 107:103728. [PMID: 32364944 DOI: 10.1016/j.jmbbm.2020.103728] [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] [Received: 12/13/2019] [Revised: 03/06/2020] [Accepted: 03/10/2020] [Indexed: 11/29/2022]
Abstract
This study examined the effect of the cooling rate on the hardness and its effect on the microstructure during porcelain firing simulation of a Pd-Ag-In-Sn-Ga metal-ceramic alloy. In practice, after each firing step for porcelain bonding, the prosthesis is cooled to room temperature before proceeding to the next firing step. The cooling step is known to allow the hardness of the metal substructure to increase. The aim of the study was to determine whether controlling the cooling rate after each porcelain-firing step increases the hardness of the Pd-Ag-based metal-ceramic alloy. The results showed that the hardness of specimens cooled at a higher cooling rate increased after each firing step compared to specimens cooled at a lower cooling rate (p < 0.05). During cooling after the firing simulation the InPd3-based phase of tetragonal structure precipitated from the Pd-Ag-rich matrix of the face-centered cubic structure. Hardening by cooling at a higher cooling rate after firing was the result of the coherency strains that formed at the interface of the Pd-Ag-rich matrix and the metastable phase based on the InPd3 phase. . The reduced hardness obtained in the specimen cooled at a lower cooling rate after firing resulted from the loss of coherency strains as the fine metastable phases based on the InPd3 phase were transformed into the coarser stable phase with decreased (c/a) of 0.88. This finding revealed that controlling the cooling rate during porcelain firing simulation improves the hardness of the Pd-Ag-In-Sn-Ga metal-ceramic alloy without an additional heat treatment of the alloy.
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Affiliation(s)
- Hye-Jeong Shin
- Department of Dental Materials, Institute of Translational Dental Science and BK21 PLUS Project, School of Dentistry, Pusan National University, Beomeo-Ri, Mulgeum-Eup, Yangsan-Si, Gyeongsangnam-Do, 626-814, South Korea
| | - Yong Hoon Kwon
- Department of Dental Materials, Institute of Translational Dental Science and BK21 PLUS Project, School of Dentistry, Pusan National University, Beomeo-Ri, Mulgeum-Eup, Yangsan-Si, Gyeongsangnam-Do, 626-814, South Korea
| | - Hyo-Joung Seol
- Department of Dental Materials, Institute of Translational Dental Science and BK21 PLUS Project, School of Dentistry, Pusan National University, Beomeo-Ri, Mulgeum-Eup, Yangsan-Si, Gyeongsangnam-Do, 626-814, South Korea.
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Kim M, Kim J, Mai HN, Kwon TY, Choi YD, Lee CH, Lee DH. Comparative clinical study of the marginal discrepancy of fixed dental prosthesis fabricated by the milling-sintering method using a presintered alloy. J Adv Prosthodont 2019; 11:280-285. [PMID: 31754418 PMCID: PMC6856311 DOI: 10.4047/jap.2019.11.5.280] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/18/2019] [Accepted: 10/29/2019] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The present study was designed to examine the clinical fit of fixed dental prosthesis fabricated by the milling-sintering method using a presintered cobalt-chromium alloy. MATERIALS AND METHODS Two single metal-ceramic crowns were fabricated via milling-sintering method and casting method in each of the twelve consecutive patients who required an implant-supported fixed prosthesis. In the milling-sintering method, the prosthetic coping was designed in computer software, and the design was converted to a non-precious alloy coping using milling and post-sintering process. In the casting method, the conventional manual fabrication process was applied. The absolute marginal discrepancy of the prostheses was evaluated intraorally using the triple-scan technique. Statistical analysis was conducted using Mann-Whitney U test (α=.05). RESULTS Eight patients (66.7%) showed a lower marginal discrepancy of the prostheses made using the milling-sintering method than that of the prosthesis made by the casting method. Statistically, the misfit of the prosthesis fabricated using the milling-sintering method was not significantly different from that fabricated using the casting method (P=.782). There was no tendency between the amount of marginal discrepancy and the measurement point. CONCLUSION The overall marginal fit of prosthesis fabricated by milling-sintering using a presintered alloy was comparable to that of the prosthesis fabricated by the conventional casting method in clinical use.
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Affiliation(s)
- Mijoo Kim
- Department of Prosthodontics, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Jaewon Kim
- Department of Periodontics and Endodontics, State University of New York at Buffalo, Buffalo, NY, USA
| | - Hang-Nga Mai
- Institute for Translational Research in Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Tae-Yub Kwon
- Department of Dental Biomaterials, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Yong-Do Choi
- Institute for Translational Research in Dentistry, Kyungpook National University, Daegu, Republic of Korea.,Department of Dental Science, Graduate School, Kyungpook National University, Daegu, Republic of Korea
| | - Cheong-Hee Lee
- Department of Prosthodontics, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Du-Hyeong Lee
- Department of Prosthodontics, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea.,Institute for Translational Research in Dentistry, Kyungpook National University, Daegu, Republic of Korea
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Wang H, Lim JY. Metal-ceramic bond strength of a cobalt chromium alloy for dental prosthetic restorations with a porous structure using metal 3D printing. Comput Biol Med 2019; 112:103364. [DOI: 10.1016/j.compbiomed.2019.103364] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 07/17/2019] [Accepted: 07/17/2019] [Indexed: 11/25/2022]
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Kaleli N, Ural Ç, Küçükekenci AS. The effect of layer thickness on the porcelain bond strength of laser-sintered metal frameworks. J Prosthet Dent 2019; 122:76-81. [DOI: 10.1016/j.prosdent.2018.12.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 12/10/2018] [Accepted: 12/10/2018] [Indexed: 10/27/2022]
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Dimitriadis K, Papadopoulos T, Agathopoulos S. Effect of Bonding Agent on Metal‐Ceramic Bond Strength between Co‐Cr Fabricated with Selective Laser Melting and Dental Feldspathic Porcelain. J Prosthodont 2019; 28:1029-1036. [DOI: 10.1111/jopr.13058] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2019] [Indexed: 11/30/2022] Open
Affiliation(s)
- Konstantinos Dimitriadis
- Department of Materials Science and Engineering, School of EngineeringUniversity of Ioannina Greece
| | | | - Simeon Agathopoulos
- Department of Materials Science and Engineering, School of EngineeringUniversity of Ioannina Greece
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Effect of ice quenching after oxidation with or without vacuum on the hardness of Pd-Ag-Au-In alloy during porcelain firing simulation. J Mech Behav Biomed Mater 2019; 94:93-109. [PMID: 30897506 DOI: 10.1016/j.jmbbm.2019.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/21/2019] [Accepted: 03/08/2019] [Indexed: 11/23/2022]
Abstract
This study examined the effect of ice-quenching after oxidation treatment with or without vacuum, on the change in the hardness of a Pd-Ag-Au-In metal-ceramic alloy during porcelain-firing simulation. The aim of the present study is to determine whether ice quenching after oxidation renders a Pd-Ag metal-ceramic alloy soft enough for easy processing without the need for an additional solution treatment and whether it affects the final hardness of the Pd-Ag metal-ceramic alloy after porcelain firing simulation. The oxidation treatment resulted in the as-cast specimen becoming homogenized, which was progressed further by vacuuming. The bench-cooling to room temperature after the oxidation resulted in precipitation. From the next firing step, the precipitation occurred during the firing process as well as subsequent bench-cooling; this was owing to the presence of a phase boundary wherein the single phase is separated into two phases between the temperatures of the oxidation treatment (1010 °C) and post-oxidation treatment (~960 °C). During the firing process until main bake, the specimen that was ice-quenched after oxidation maintained a higher hardness than the bench-cooled specimen, particularly for the oxidation treated specimen with vacuum (p < 0.05). The mechanism of ice-quenching after oxidation with vacuum to induce further hardening during the firing process involved more active precipitation; this was attributed to the further progress of homogenization during the oxidation. The precipitation reaction in the present study corresponded to the Pd-In binary phase diagram, illustrating that as the firing proceeded, the Pd3(In,Sn,Ga) phase was precipitated from the Pd-Ag-Au-rich matrix. The findings revealed that ice quenching after oxidation makes the alloy soft enough for easy processing without an additional heat treatment and does not affect the final hardness of the Pd-Ag metal-ceramic alloy after porcelain firing simulation.
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Comparative Analysis of Mechanical Properties and Metal-Ceramic Bond Strength of Co-Cr Dental Alloy Fabricated by Different Manufacturing Processes. MATERIALS 2018; 11:ma11101801. [PMID: 30249000 PMCID: PMC6213922 DOI: 10.3390/ma11101801] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/03/2018] [Accepted: 09/20/2018] [Indexed: 11/23/2022]
Abstract
Cobalt-chromium (Co-Cr) alloy is a widely used base material for dental fixed prostheses. These restorations can be produced through casting technique, subtractive or additive manufacturing technologies. However, limited information is available regarding the influence of manufacturing techniques on the properties of Co-Cr alloy since most studies used different chemical compositions of Co-Cr alloy for different manufacturing methods. This study compares the mechanical properties, metal-ceramic bond strength, and microstructures of specimens produced by casting, milling, and selective laser melting (SLM) from one single Co-Cr alloy composition. The mechanical properties of the alloy were investigated by tensile and Vickers hardness tests, and metal-ceramic bond strength was determined by three-point bending. Scanning electron microscopy (SEM) with backscattered electron (BSE) images and optical microphotographs were used to analyze the surface microstructures. Compared with the casting and milling techniques, SLM Co-Cr alloy specimens indicated enhanced mechanical properties and comparable metal-ceramic bond strength. Besides, the microstructures of the SLM specimens showed finer grains with more second phase particles than the casting and milling specimens. The results of our study indicate that SLM might be superior to traditional techniques for the manufacturing of fixed dental restorations.
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Comparative Study of the Fit Accuracy of Full-Arch Bar Frameworks Fabricated with Different Presintered Cobalt-Chromium Alloys. BIOMED RESEARCH INTERNATIONAL 2018; 2018:1962514. [PMID: 30175117 PMCID: PMC6098887 DOI: 10.1155/2018/1962514] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 06/06/2018] [Accepted: 07/08/2018] [Indexed: 11/17/2022]
Abstract
Purpose This study was to measure the geometric discrepancies that occur during the sintering contraction of presintered Co-Cr alloys in a full-arch bar framework and to compare the variations between alloys from different manufacturers. Materials and Methods Eighteen implant-supported full-arch bar frameworks were fabricated through a soft-machining process using presintered Co-Cr alloy blocks: Ceramill Sintron (CS), Soft Metal (SM), and Sintermetall (SML) (n=6 for each group). The sintered frameworks were digitized using a structured light scanner, and the scan images were superimposed on the reference design. The geometric discrepancies of the sintered frameworks were three-dimensionally analyzed for horizontal, angular, and internal discrepancies. Kruskal-Wallis and Mann-Whitney U tests were used to compare the discrepancies among the groups (α=.05). Results Significant differences were found in the geometric discrepancy measurements among the groups. The CS group showed larger horizontal and angular discrepancies, followed by the SM and SML groups (P<.001). The root mean square (RMS) values for internal discrepancy were not statistically different among the groups (P=.778). Conclusion The geometric discrepancies of full-arch bar frameworks fabricated using the soft-machining process were affected by accuracies in sintering contraction of presintered alloys.
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Haider A, Azam OF, Talha M, Akhtar S. Ni-Cr-Mo Alloy for Dental Prostheses with Low Melting Temperature. KEY ENGINEERING MATERIALS 2018; 778:301-305. [DOI: 10.4028/www.scientific.net/kem.778.301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Ni-Cr alloys are popular for dental prostheses for the reason of economy and few better characteristics in comparison to expensive gold based alloys. However, Ni-Cr alloy developed locally has higher melting point around 1400°C as compared to that of proprietary alloys. The Ni-Cr alloys contain major alloying elements in following range: 50-80 % Ni, 10-30 % Cr, 3-10 % Mo. Minor addition is made to have requisite properties suitable for dental prostheses. In this work investigation was carried out to find out optimum chemistry to have melting point of the alloy in the range of 1100-1200°C without compromising the requisite mechanical properties. Developed alloy was characterized using Scanning Electron Microscope, Inductive Coupled Spark Plasma, Hardness Tester and Differential Scanning Calorimetry. Results were analyzed and acceptable samples tested at dental labs for trial use and suitability for dental prostheses.
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Øilo M, Nesse H, Lundberg OJ, Gjerdet NR. Mechanical properties of cobalt-chromium 3-unit fixed dental prostheses fabricated by casting, milling, and additive manufacturing. J Prosthet Dent 2018; 120:156.e1-156.e7. [PMID: 29705672 DOI: 10.1016/j.prosdent.2017.12.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 12/22/2017] [Accepted: 12/27/2017] [Indexed: 10/17/2022]
Abstract
STATEMENT OF PROBLEM New additive manufacturing techniques for nonprecious alloys have made the fabrication of metal-ceramic fixed partial dentures (FPDs) less expensive and less time-consuming. However, whether the mechanical properties produced by these techniques are comparable is unclear. PURPOSE The purpose of this in vitro study was to evaluate the mechanical properties of cobalt-chromium frameworks for FPDs fabricated by 3 different techniques. MATERIAL AND METHODS Thirty frameworks for 3-unit FPDs were fabricated by traditional casting, computer-aided design and computer-aided manufacturing (CAD-CAM) milling, and selective laser melting (SLM), with n=10 in each group. The frameworks were weighed, and distal and mesial connector areas measured. The frameworks were cemented and loaded centrally (0.5 mm/s) until deformation above 1 mm occurred. Stiffness was measured as the slope of the axis between 500 and 2000 N. Microhardness was measured on sectioned specimens by Vickers indentation. The microstructure was also analyzed by scanning electron microscopy. One-way ANOVA with Tukey post hoc analysis was used to compare the groups (α=.05). RESULTS The framework design differed among the groups, making a comparison of strength impossible. The milled frameworks appeared bulky, while the cast and SLM frameworks were more slender. Statistically significant differences were found in microhardness, stiffness, wall thickness, weight, and connector size (P<.05), and a significant correlation was found between hardness and stiffness (-0.4, P<.005). CONCLUSIONS Fabrication method affects the design, stiffness, microhardness, and microstructure of cobalt-chromium FPD frameworks. The SLM frameworks were stiffer and harder than the cast and milled specimens.
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Affiliation(s)
- Marit Øilo
- Associate Professor, Department of Clinical Dentistry, Faculty of Medicine, University of Bergen, Bergen, Norway.
| | - Harald Nesse
- Head, Dental Clinics, Department of Clinical Dentistry, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Odd Johan Lundberg
- Senior Engineer, Department of Clinical Dentistry, Faculty of Medicine, University of Bergen, Bergen, Norway
| | - Nils Roar Gjerdet
- Professor, Department of Clinical Dentistry, Faculty of Medicine, University of Bergen, Bergen, Norway
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Antanasova M, Kocjan A, Kovač J, Žužek B, Jevnikar P. Influence of thermo-mechanical cycling on porcelain bonding to cobalt–chromium and titanium dental alloys fabricated by casting, milling, and selective laser melting. J Prosthodont Res 2018; 62:184-194. [DOI: 10.1016/j.jpor.2017.08.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 07/24/2017] [Accepted: 08/17/2017] [Indexed: 11/25/2022]
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Kim MJ, Shin HJ, Kim HI, Kwon YH, Seol HJ. Effect of ice-quenching after oxidation treatment on hardening of a Pd-Cu-Ga-Zn alloy for bonding porcelain. J Mech Behav Biomed Mater 2017; 79:83-91. [PMID: 29287226 DOI: 10.1016/j.jmbbm.2017.12.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 11/16/2017] [Accepted: 12/14/2017] [Indexed: 10/18/2022]
Abstract
This study examined the effect of ice-quenching after oxidation treatment on hardness change of a Pd-Cu-Ga-Zn metal-ceramic alloy during porcelain firing simulation. Although not statistically significant, the alloy was softened slightly during porcelain firing simulation with conventional slow cooling rate. On the other hand, the hardness increased significantly by ice-quenching instead of the slow cooling after oxidation (p<0.001). The gap in the final hardness depending on ice-quenching occurred in the matrix and plate-like precipitates but not in the particle-like structure without plate-like precipitates (p<0.05). The mechanism of ice-quenching after oxidation to prevent softening and induce hardening during porcelain firing simulation involved the more active precipitation and retardation of microstructural coarsening. In conclusion, for practical work on Pd-Cu-Ga-Zn alloys, the oxidation treatment followed by ice-quenching instead of slow cooling is recommended for the simultaneous oxidation and hardening effects on the alloy.
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Affiliation(s)
- Min-Jung Kim
- Department of Dental Materials, Institute of translational dental science and BK21 PLUS Project, School of Dentistry, Pusan National University, Beomeo-Ri, Mulgeum-Eup, Yangsan-Si, Gyeongsangnam-Do 626-814, South Korea
| | - Hye-Jeong Shin
- Department of Dental Materials, Institute of translational dental science and BK21 PLUS Project, School of Dentistry, Pusan National University, Beomeo-Ri, Mulgeum-Eup, Yangsan-Si, Gyeongsangnam-Do 626-814, South Korea
| | - Hyung-Il Kim
- Department of Dental Materials, Institute of translational dental science and BK21 PLUS Project, School of Dentistry, Pusan National University, Beomeo-Ri, Mulgeum-Eup, Yangsan-Si, Gyeongsangnam-Do 626-814, South Korea
| | - Yong Hoon Kwon
- Department of Dental Materials, Institute of translational dental science and BK21 PLUS Project, School of Dentistry, Pusan National University, Beomeo-Ri, Mulgeum-Eup, Yangsan-Si, Gyeongsangnam-Do 626-814, South Korea
| | - Hyo-Joung Seol
- Department of Dental Materials, Institute of translational dental science and BK21 PLUS Project, School of Dentistry, Pusan National University, Beomeo-Ri, Mulgeum-Eup, Yangsan-Si, Gyeongsangnam-Do 626-814, South Korea.
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Scheithauer U, Weingarten S, Johne R, Schwarzer E, Abel J, Richter HJ, Moritz T, Michaelis A. Ceramic-Based 4D Components: Additive Manufacturing (AM) of Ceramic-Based Functionally Graded Materials (FGM) by Thermoplastic 3D Printing (T3DP). MATERIALS (BASEL, SWITZERLAND) 2017; 10:E1368. [PMID: 29182541 PMCID: PMC5744303 DOI: 10.3390/ma10121368] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 11/09/2017] [Accepted: 11/25/2017] [Indexed: 11/16/2022]
Abstract
In our study, we investigated the additive manufacturing (AM) of ceramic-based functionally graded materials (FGM) by the direct AM technology thermoplastic 3D printing (T3DP). Zirconia components with varying microstructures were additively manufactured by using thermoplastic suspensions with different contents of pore-forming agents (PFA), which were co-sintered defect-free. Different materials were investigated concerning their suitability as PFA for the T3DP process. Diverse zirconia-based suspensions were prepared and used for the AM of single- and multi-material test components. All of the samples were sintered defect-free, and in the end, we could realize a brick wall-like component consisting of dense (<1% porosity) and porous (approx. 5% porosity) zirconia areas to combine different properties in one component. T3DP opens the door to the AM of further ceramic-based 4D components, such as multi-color, multi-material, or especially, multi-functional components.
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Affiliation(s)
- Uwe Scheithauer
- Processes and Components, Fraunhofer Institute for Ceramic Technologies and Systems (IKTS), 01277 Dresden, Germany.
| | - Steven Weingarten
- Processes and Components, Fraunhofer Institute for Ceramic Technologies and Systems (IKTS), 01277 Dresden, Germany.
| | - Robert Johne
- Fraunhofer Singapore, Singapore 639798, Singapore.
| | - Eric Schwarzer
- Processes and Components, Fraunhofer Institute for Ceramic Technologies and Systems (IKTS), 01277 Dresden, Germany.
| | - Johannes Abel
- Processes and Components, Fraunhofer Institute for Ceramic Technologies and Systems (IKTS), 01277 Dresden, Germany.
| | - Hans-Jürgen Richter
- Processes and Components, Fraunhofer Institute for Ceramic Technologies and Systems (IKTS), 01277 Dresden, Germany.
| | - Tassilo Moritz
- Processes and Components, Fraunhofer Institute for Ceramic Technologies and Systems (IKTS), 01277 Dresden, Germany.
| | - Alexander Michaelis
- Processes and Components, Fraunhofer Institute for Ceramic Technologies and Systems (IKTS), 01277 Dresden, Germany.
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Metal-composite adhesion based on diazonium chemistry. Dent Mater 2017; 33:e393-e404. [DOI: 10.1016/j.dental.2017.07.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 06/11/2017] [Accepted: 07/13/2017] [Indexed: 11/21/2022]
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Koutsoukis T, Zinelis S, Eliades G, Al-Wazzan K, Rifaiy MA, Al Jabbari YS. Selective Laser Melting Technique of Co-Cr Dental Alloys: A Review of Structure and Properties and Comparative Analysis with Other Available Techniques. J Prosthodont 2017; 24:303-12. [PMID: 26129918 DOI: 10.1111/jopr.12268] [Citation(s) in RCA: 172] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2014] [Indexed: 11/27/2022] Open
Abstract
PURPOSE The aim of this study was to review the effect of selective laser melting (SLM) procedure on the properties of dental structures made of Co-Cr alloys and to evaluate its quality and compare it to those produced by conventional casting and milling fabrication techniques. MATERIALS AND METHODS A computerized database search using PubMed and Scopus was conducted for peer-reviewed scientific research studies regarding the use of SLM in Co-Cr dental alloys with no restrictions for publication years. The search engines provided hundreds of results, and only 48 scientific research papers, case studies, or literature reviews were considered relevant for this review. RESULTS The innovative manufacturing concept of SLM offers many advantages compared with casting and milling fabrication techniques. SLM provides different microstructure from casting and milling with minimal internal porosity and internal fitting, marginal adaptation, and comparable bond strength to porcelain. Mechanical and electrochemical properties of SLM structures are enhanced compared to cast, while clinical longevity of single-metal ceramic crowns is comparable to Au-Pt dental alloy. CONCLUSION The SLM technique provides dental prosthetic restorations more quickly and less expensively without compromising their quality compared with restorations prepared by casting and milling techniques. CLINICAL SIGNIFICANCE The current SLM devices provide metallic restorations made of Co-Cr alloys for removable and fixed partial dentures without compromising the alloy or restoration properties at a fraction of the time and cost, showing great potential to replace the aforementioned fabrication techniques in the long term; however, further clinical studies are essential to increase the acceptance of this technology by the worldwide dental community.
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Affiliation(s)
- Theodoros Koutsoukis
- Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Spiros Zinelis
- Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.,Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - George Eliades
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Khalid Al-Wazzan
- Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.,Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Mohammed Al Rifaiy
- Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.,Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Youssef S Al Jabbari
- Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.,Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
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Kaleli N, Saraç D. Comparison of porcelain bond strength of different metal frameworks prepared by using conventional and recently introduced fabrication methods. J Prosthet Dent 2017; 118:76-82. [DOI: 10.1016/j.prosdent.2016.12.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Revised: 12/09/2016] [Accepted: 12/09/2016] [Indexed: 11/16/2022]
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Kim EH, Lee DH, Kwon SM, Kwon TY. A microcomputed tomography evaluation of the marginal fit of cobalt-chromium alloy copings fabricated by new manufacturing techniques and alloy systems. J Prosthet Dent 2016; 117:393-399. [PMID: 27677219 DOI: 10.1016/j.prosdent.2016.08.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 08/01/2016] [Accepted: 08/01/2016] [Indexed: 11/18/2022]
Abstract
STATEMENT OF PROBLEM Although new digital manufacturing techniques are attracting interest in dentistry, few studies have comprehensively investigated the marginal fit of fixed dental prostheses fabricated with such techniques. PURPOSE The purpose of this in vitro microcomputed tomography (μCT) study was to evaluate the marginal fit of cobalt-chromium (Co-Cr) alloy copings fabricated by casting and 3 different computer-aided design and computer-aided manufacturing (CAD-CAM)-based processing techniques and alloy systems. MATERIAL AND METHODS Single Co-Cr metal crowns were fabricated using 4 different manufacturing techniques: casting (control), milling, selective laser melting, and milling/sintering. Two different commercial alloy systems were used for each fabrication technique (a total of 8 groups; n=10 for each group). The marginal discrepancy and absolute marginal discrepancy of the crowns were determined with μCT. For each specimen, the values were determined from 4 different regions (sagittal buccal, sagittal lingual, coronal mesial, and coronal distal) by using imaging software and recorded as the average of the 4 readings. For each parameter, the results were statistically compared with 2-way analysis of variance and appropriate post hoc analysis (using Tukey or Student t test) (α=.05). RESULTS The milling and selective laser melting groups showed significantly larger marginal discrepancies than the control groups (70.4 ±12.0 and 65.3 ±10.1 μm, respectively; P<.001), whereas the milling/sintering groups exhibited significantly smaller values than the controls (P=.004). The milling groups showed significantly larger absolute marginal discrepancy than the control groups (137.4 ±29.0 and 139.2 ±18.9 μm, respectively; P<.05). In the selective laser melting and milling/sintering groups, the absolute marginal discrepancy values were material-specific (P<.05). Nonetheless, the milling/sintering groups yielded statistically comparable (P=.935) or smaller (P<.001) absolute marginal discrepancies to the control groups. CONCLUSIONS The findings of this in vitro μCT study showed that the marginal fit values of the Co-Cr alloy greatly depended on the fabrication methods and, occasionally, the alloy systems. Fixed dental prostheses produced by using the milling/sintering technique can be considered clinically acceptable in terms of marginal fit.
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Affiliation(s)
- Eun-Ha Kim
- Graduate student, Department of Medical and Biological Engineering, Graduate School, Kyungpook National University, Daegu, Republic of Korea
| | - Du-Hyeong Lee
- Assistant Professor, Department of Prosthodontics, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Sung-Min Kwon
- Graduate student, Department of Dental Science, Graduate School, Kyungpook National University, Daegu, Republic of Korea
| | - Tae-Yub Kwon
- Associate Professor, Department of Dental Biomaterials, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea.
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Minesaki Y, Murahara S, Kajihara Y, Takenouchi Y, Tanaka T, Suzuki S, Minami H. Effect of metal conditioner on bonding of porcelain to cobalt-chromium alloy. J Adv Prosthodont 2016; 8:1-8. [PMID: 26949481 PMCID: PMC4769884 DOI: 10.4047/jap.2016.8.1.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 11/26/2015] [Accepted: 12/14/2015] [Indexed: 11/22/2022] Open
Abstract
PURPOSE The purpose of this study was to evaluate the efficacy of two different metal conditioners for non-precious metal alloys for the bonding of porcelain to a cobalt-chromium (Co-Cr) alloy. MATERIALS AND METHODS Disk-shaped specimens (2.5×10.0 mm) were cast with Co-Cr alloy and used as adherend materials. The bonding surfaces were polished with a 600-grid silicon carbide paper and airborne-particle abraded using 110 µm alumina particles. Bonding specimens were fabricated by applying and firing either of the metal conditioners on the airborne-particle abraded surface, followed by firing porcelain into 5 mm in diameter and 3 mm in height. Specimens without metal conditioner were also fabricated. Shear bond strength for each group (n=8) were measured and compared (α=.05). Sectional view of bonding interface was observed by SEM. EDS analysis was performed to determine the chemical elements of metal conditioners and to determine the failure modes after shear test. RESULTS There were significant differences among three groups, and two metal conditioner-applied groups showed significantly higher values compared to the non-metal conditioner group. The SEM observation of the sectional view at bonding interface revealed loose contact at porcelain-alloy surface for non-metal conditioner group, however, close contact at both alloy-metal conditioner and metal conditioner-porcelain interfaces for both metal conditioner-applied groups. All the specimens showed mixed failures. EDS analysis showed that one metal conditioner was Si-based material, and another was Ti-based material. Si-based metal conditioner showed higher bond strengths compared to the Ti-based metal conditioner, but exhibited more porous failure surface failure. CONCLUSION Based on the results of this study, it can be stated that the application of metal conditioner is recommended for the bonding of porcelain to cobalt-chromium alloys.
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Affiliation(s)
- Yoshito Minesaki
- Kagoshima University Medical and Dental Hospital, Fixed Prosthetic Clinic, Kagoshima, Japan
| | - Sadaaki Murahara
- Kagoshima University Graduate School of Medical and Dental Sciences, Department of Fixed Prosthodontics, Kagoshima, Japan
| | - Yutaro Kajihara
- Kagoshima University Medical and Dental Hospital, Fixed Prosthetic Clinic, Kagoshima, Japan
| | | | - Takuo Tanaka
- Kagoshima University Graduate School of Medical and Dental Sciences, Department of Fixed Prosthodontics, Kagoshima, Japan
| | - Shiro Suzuki
- School of Dentistry, University of Alabama at Birmingham, Division of Biomaterials, Birmingham, Alabama, United States of America
| | - Hiroyuki Minami
- Kagoshima University Graduate School of Medical and Dental Sciences, Department of Fixed Prosthodontics, Kagoshima, Japan
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Al Bakkar H, Spintzyk S, Schille C, Schweizer E, Geis-Gerstorfer J, Rupp F. Influence of a bonding agent on the bond strength between a dental Co-Cr alloy and nine different veneering porcelains. BIOMED ENG-BIOMED TE 2016; 61:509-517. [PMID: 26966925 DOI: 10.1515/bmt-2015-0101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 02/02/2016] [Indexed: 11/15/2022]
Abstract
AbstractAdequate bonding between dental veneering porcelains and non-precious metal alloys is a main factor for the long-term functionality of porcelain fused to metal restorations. Although a huge number of veneering porcelains are on the market, only few studies have reported about the role of bonding agents for the bond strength at their respective interface to cobalt-chromium (Co-Cr). The aim of this study was to compare the influence of a metal-ceramic bonding agent for Co-Cr alloys on the bond strength of metal-ceramic systems. The bond strength test was done according to ISO 9693 with additional detection of the first acoustic crack initiated signal while testing. The bonding agent had only minor effects on the bond strength of the different Co-Cr/ceramic systems. Only three of the nine studied systems showed statistically significant differences (p<0.05) upon applying the bonding agent. Scanning electron microscopy (SEM) showed cracks predominantly caused by adhesive failure. Based on this study, Co-Cr alloys veneered with porcelains with and without a bonding agent exceeded the minimum bond strength of 25 MPa required according to ISO 9693. However, if bond strength values based on acoustic signals were calculated, values below the threshold of 25 MPa could be observed. Such findings are important for failures caused by the occurrence of early cracks.
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Anwar M, Tripathi A, Kar SK, Sekhar KC. Effect of PFM Firing Cycles on the Mechanical Properties, Phase Composition, and Microstructure of Nickel-Chromium Alloy. J Prosthodont 2015. [PMID: 26215348 DOI: 10.1111/jopr.12328] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
PURPOSE The purpose of this study was to compare the mechanical properties of beryllium-free nickel-chromium (Ni-Cr) dental casting alloy before and after each porcelain firing cycle (once fired, twice fired, and thrice fired) and to relate these properties to the microstructural changes and changes in X-ray diffraction patterns of Ni-Cr alloy that occur after each porcelain firing cycle. MATERIAL AND METHODS Forty tensile bar specimens and 20 disc-shaped specimens of Ni-Cr alloy were prepared. These specimens were divided into four groups. The first group was not heat treated and tested in the as-cast condition, thus serving as control group. The second, third, and fourth groups were fired once, twice, and thrice, respectively. Tensile bar specimens were loaded to failure in tension using a universal testing machine. Values of ultimate tensile strength, 0.1% yield strength, and percentage elongations were determined. Microstructural study and hardness testing were done using an optical microscope and digital Vickers hardness tester, respectively, on disc-shaped specimens. Disc-shaped specimens were again used to obtain the X-ray diffraction patterns by using diffractometer Bruker D8 focus. Statistical comparisons of the mechanical properties and hardness of the alloy were made with ANOVA. Intergroup comparisons of the data in the as-cast and fired specimens were analyzed by applying Tukey's HSD multiple comparison tests. RESULTS Before porcelain firing, the alloy exhibited higher ultimate tensile strength (548 MPa), 0.1% yield strength (327 MPa), hardness (192 HV), and lower elongation values (18%). After each firing cycle, there was a significant (p < 0.001) decrease in ultimate strength (464 MPa for three times fired specimens), 0.1% yield strength (284 MPa for three times fired group), and hardness (164 HV for three times fired group) and significant (p < 0.001) increase in elongation value (28% for three times fired group) of Ni-Cr alloy. The microstructure of the control group specimen exhibited heterogeneous microstructure, and after each firing, microstructure of the alloy was gradually homogenized by formation of grain boundaries at the interdendritic interfaces. X-ray diffraction pattern shows that the alloy exhibited four strong diffraction peaks within the range of 2θ = 40° to 100°. After a third firing, intensity of these planes increased. CONCLUSIONS Results of this study confirmed that nickel-based alloys become weaker after each firing process. After firing treatment, the microstructure of alloys showed decreased dendritic structure (i.e., homogenization, which was responsible for decrease in strength and an increase in ductility of the alloy); however, this decreased strength and hardness of Ni-Cr alloy after heat treatment was still superior to those of the most noble metal alloys used in dentistry. X-ray diffraction study showed that firing process led to relieving of stresses, which ultimately resulted in stability in the crystal structure of alloy.
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Affiliation(s)
- Mohd Anwar
- Department of Prosthodontics, Saraswati Dental College and Hospital, Lucknow, India
| | - Arvind Tripathi
- Dean Postgraduate Studies and Research, Saraswati Dental College and Hospital, Lucknow, India
| | - Sushil Kumar Kar
- Department of Prosthodontics, Saraswati Dental College and Hospital, Lucknow, India
| | - K Chandra Sekhar
- Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur, India
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Effect of heating palladium-silver alloys on ceramic bond strength. J Prosthet Dent 2015. [PMID: 26213266 DOI: 10.1016/j.prosdent.2015.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
STATEMENT OF PROBLEM The effects of different heat treatments on the internal oxidation and metal-ceramic bond in Pd-Ag alloys with different trace elements require further documentation. PURPOSE The purpose of this in vitro study was to determine whether heat treatment affects the metal-ceramic bond strength of 2 Pd-Ag alloys containing different trace elements. MATERIAL AND METHODS Thirteen cast specimens (25×3×0.5 mm) from each of 2 Pd-Ag alloy groups (W-1 and Argelite 61+3) were allocated to heat treatments before porcelain application: heating under reduced atmospheric pressure of 0.0014 MPa and 0.0026 MPa and heating under normal atmospheric pressure. Bond strengths were evaluated using a 3-point bending test according to ISO9693. Results were analyzed using 2-way ANOVA and Tukey HSD test (α=.05). Visual observation was used to determine the failure types of the fractured specimens. Scanning electron microscopy and energy dispersive spectroscopy were used to study morphologies, elemental compositions, and distributions in the specimens. RESULTS The W-1 group had a mean bond strength significantly higher than that of Argelite 61+3 (P<.001). Heating under reduced atmospheric pressures of 0.0014 MPa and 0.0026 MPa resulted in similar bond strengths (P=.331), and both pressures had significantly higher bond strengths than that of heating under normal atmospheric pressure (P=.002, P<.001). Heating under different air pressures resulted in Pd-Ag alloys that contained either Sn or In and Ga, with various degrees of internal oxidation and different quantities of metallic nodules. CONCLUSIONS Heating under reduced atmospheric pressure effectively improved the bond strength of the ceramic-to-Pd-Ag alloys.
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Li J, Ye X, Li B, Liao J, Zhuang P, Ye J. Effect of oxidation heat treatment on the bond strength between a ceramic and cast and milled cobalt-chromium alloys. Eur J Oral Sci 2015; 123:297-304. [PMID: 26104804 DOI: 10.1111/eos.12199] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2015] [Indexed: 11/28/2022]
Abstract
There is a dearth of dental scientific literature on the effect of different oxidation heat treatments (OHTs) (as surface pretreatments) on the bonding performance of cast and milled cobalt-chromium (CoCr) alloys. The objective of this study was to evaluate the effect of different OHTs on the bond strength between a ceramic and cast and milled CoCr alloys. Cobalt-chromium metallic specimens were prepared using either a cast or a milled method. Specimens were subjected to four different OHT methods: without OHT; OHT under normal atmospheric pressure; OHT under vacuum; and OHT under vacuum followed by sandblasting. The metal-ceramic bond strength was evaluated using a three-point bending test according to ISO9693. Scanning electron microscopy and energy-dispersive spectroscopy were used to study the specimens' microstructure and elemental composition. The bond strength was not affected by the CoCr manufacturing method. Oxidation heat treatment performed under normal atmospheric pressure resulted in the highest bond strength. The concentration of oxygen on the alloy surfaces varied with the different pretreatment methods in the following order: OHT under normal atmospheric pressure > OHT under vacuum > without OHT ≈ OHT under vacuum followed by sandblasting.
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Affiliation(s)
- Jieyin Li
- Department of Prosthodontics, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Department of Stomatology, Jieyang People's Hospital, Jieyang, China
| | - Xiuhua Ye
- Department of Prosthodontics, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Bohua Li
- Department of Stomatology, Henan Provincial People's Hospital, Zhengzhou, China
| | - Juankun Liao
- Department of Prosthodontics, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Peilin Zhuang
- Department of Prosthodontics, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Jiantao Ye
- Department of Prosthodontics, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
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Håff A, Löf H, Gunne J, Sjögren G. A retrospective evaluation of zirconia-fixed partial dentures in general practices: An up to 13-year study. Dent Mater 2015; 31:162-70. [DOI: 10.1016/j.dental.2014.11.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 06/27/2014] [Accepted: 11/14/2014] [Indexed: 11/26/2022]
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