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Korkes A, Jomaa J, Kavouris A, Lalani T, King P, Lee S, Li H, Li A, Khuu W, Law KHJ, Abduo J. Seating accuracy of removable partial denture frameworks fabricated by different digital workflows in comparison to conventional workflow. J Prosthodont 2024. [PMID: 39118292 DOI: 10.1111/jopr.13923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 07/28/2024] [Indexed: 08/10/2024] Open
Abstract
PURPOSE To evaluate the seating accuracy of removable partial denture (RPD) frameworks fabricated by two digital workflows involving selective laser melting (SLM) in comparison to the conventional workflow. MATERIALS AND METHODS A Kennedy class III modification 1 partially edentulous mandibular arch was used as a master model. Three RPD framework groups were included: (1) a conventional workflow group with conventional impression and casting (CC), (2) a partial digital workflow group with conventional impression and digital fabrication (CD), and (3) a complete digital workflow group with digital impression and digital fabrication (DD). A total of 10 frameworks were produced for each group. The marginal gaps at the occlusal rests, retention arms, and reciprocating arms were measured by a traveling microscope. The data were analyzed with the one-way analysis of variance test. RESULTS At the framework level, the most superior fit was observed for the CD group (79.5 µm) followed by DD (85.3 µm) and CC (114.2 µm) groups. The CD and DD groups were significantly superior to CC (p < 0.001). This fit pattern was consistent for the retention and reciprocating arms, while the occlusal rest fit was similar among all the groups. CONCLUSIONS The SLM frameworks had a promising seating accuracy in comparison to conventional frameworks. The type of impression, conventional or digital, did not affect the accuracy of SLM frameworks. The differences observed in the present study are likely to be of minimal clinical significance.
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Affiliation(s)
- Andrea Korkes
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Janine Jomaa
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Anastasios Kavouris
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Tahyr Lalani
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Phillip King
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Samantha Lee
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Hongyi Li
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Aixi Li
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Wilson Khuu
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Ka Ho Jesper Law
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
| | - Jaafar Abduo
- Restorative Section, Melbourne Dental School, Melbourne University, Melbourne, Victoria, Australia
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Maalhagh-Fard A, Ostrander NJ, Saunders TR, Dadul T. Comparison between selective laser melted and cast removable partial denture frameworks. J Prosthet Dent 2024:S0022-3913(24)00459-1. [PMID: 39117493 DOI: 10.1016/j.prosdent.2024.06.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 06/26/2024] [Accepted: 06/28/2024] [Indexed: 08/10/2024]
Abstract
STATEMENT OF PROBLEM Cast cobalt chromium (Co-Cr) frameworks for removable partial dentures may have undesirable micromechanical properties leading to clinical failures. Co-Cr frameworks made by selective laser melting (SLM) may have improved micromechanical properties, but comparative studies are lacking. PURPOSE The purpose of this in vitro study was to compare the micromechanical properties of SLM for Co-Cr alloys with those produced by conventional casting. MATERIAL AND METHODS The International Organization for Standardization (ISO) standards were used to determine material constants and failure stress. For flexural testing, 31×11×1.2-mm specimens were cast (n=10) and selective laser melted (n=10) and tested with a 20-mm support span in a 3-point configuration. The cast specimens had been held in a furnace for 5 minutes to encourage dendrite and columnar grain growth to represent the clinical cast RPD framework microstructure at the zone of failure. These failure points were observed with optical and scanning electron microscopy. Three-point bend tests, mimicking the fracture of RPD clasps, were done at room temperature using a universal testing machine (Instron 5569) to characterize the mechanical properties of cast and SLM specimens. The elastic modulus (E), bending yield strength (σy), strain to yield (εy), ultimate flexural stress (σufs), and resilience (Ur) values for the cast and SLM groups were compared using 2-sided t tests (α=.05) and Weibull analysis was completed with the confidence interval of 95%. RESULTS The SLM and cast Co-Cr groups have statistically significant differences. The SLM mean values for toughness, yield strength, strain to yield, resilience, and strain to failure were statistically higher than the cast mean values (P<.001). The Weibull distribution of ultimate flexure strength was also significantly different for both groups (P<.001). CONCLUSIONS SLM Co-Cr alloy was found to be tougher than cast Co-Cr alloy. The SLM alloy underwent more flexure before permanent deformation, withstood greater stresses, and had greater failure stress predictability than cast alloy.
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Affiliation(s)
- Ahmad Maalhagh-Fard
- Associate Professor and Director of Faculty Success Program, University of Detroit Mercy School of Dentistry, Detroit, Mich.
| | | | - Timothy R Saunders
- Clinical Professor, University of Detroit Mercy School of Dentistry, Detroit, Mich
| | - Tenzin Dadul
- Clinical Professor, University of Detroit Mercy School of Dentistry, Detroit, Mich; Ross School of Business, University of Michigan, Mich
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Almufleh B, Arellanob A, Tamimi F. Patient-reported outcomes and framework fit accuracy of removable partial dentures fabricated using digital techniques: A systematic review and meta-analysis. J Prosthodont 2024; 33:626-636. [PMID: 37930081 DOI: 10.1111/jopr.13786] [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: 05/15/2023] [Revised: 09/26/2023] [Accepted: 10/20/2023] [Indexed: 11/07/2023] Open
Abstract
PURPOSE This review aimed to summarize the evidence on patient-reported outcomes and clinical performance of digitally fabricated removable partial dentures (RPDs) compared to traditionally fabricated dentures. METHODS Three databases were systematically searched (PubMed, CENTRAL, and Wiley online library) for clinical studies comparing digitally and conventionally fabricated RPDs regardless of data acquisition methods used for fabrication. The Cochrane Collaboration risk of bias assessment tool 2 and the Oxford Center for Evidence-based Medicine tool were used to assess risk of bias, and level of evidence, respectively. Descriptive narrative analysis was used to summarize data on patient-reported outcomes, as there were inadequate studies to pool data in a meta-analysis. A random-effects model was used to analyze the data of framework fit accuracy. RESULTS Ten randomized controlled trials were included in the systematic review, and 4 were included in the meta-analysis. Two studies showed that digitally fabricated RPDs are associated with higher patient satisfaction than conventionally fabricated RPDs (with a mean difference of 12.5 mm on a 100-satisfaction scale, p = .008). The pooled standardized mean difference for framework fit accuracy was 0.49 (p = 0.02) in favor of conventionally fabricated RPDs, which showed that conventionally fabricated RPDs have a quantitatively better fit compared to digitally fabricated RPDs. However, clinical evaluation studies showed that both frameworks have clinically acceptable fit. CONCLUSIONS Current evidence shows that digitally fabricated RPDs are associated with higher patient satisfaction compared to conventionally fabricated RPDs. However, the scarcity of literature here warrants the generalization of this conclusion. Both digitally and conventionally fabricated metal RPD frameworks showed acceptable fit clinically.
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Affiliation(s)
- Balqees Almufleh
- Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Alexia Arellanob
- College of Dental Medicine, QU Health, Qatar University, Doha, Qatar
| | - Faleh Tamimi
- College of Dental Medicine, QU Health, Qatar University, Doha, Qatar
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Elsayed ME, El-Bayoumi DA, Hebeshi AM, El-Tamimi KM. Trueness of 3D-printed cobalt chromium versus titanium removable partial denture clasps. J Prosthodont 2024. [PMID: 39039643 DOI: 10.1111/jopr.13906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 06/03/2024] [Accepted: 06/06/2024] [Indexed: 07/24/2024] Open
Abstract
PURPOSE The purpose of this in vitro study was to evaluate the trueness of removable partial denture clasps fabricated with titanium (Ti) through the selective laser melting (SLM) technique compared to cobalt-chromium alloys (CoCr). MATERIALS AND METHODS A virtual Aker clasp was designed on a scanned tooth, and SLM printers were used to print 20 claps using cobalt chromium (n = 10) and titanium alloy (n = 10). The deviation between the printed clasps and reference design was measured using the surface matching software (Geomagic control x) at rest, retentive tip, reciprocal tip, retentive shoulder, and reciprocal shoulder. An Independent t-test was used to determine the influence of 3D-printed material on the trueness (a = 0.05). RESULTS The gap distance in mm between the reference design and printed in titanium showed an average of 0.0001 ±0.0544, 0.0256 ±0.1309, 0.0230 ±0.1028, 0.0701 ±0.1234, and 0.0013 ±0.0735 mm in rest, reciprocal arm tip, retentive arm tip, retentive arm shoulder, and reciprocal arm shoulder, respectively. The gap distance in mm between the reference design and printed clasps in CoCr alloy showed an average of 0.0316 ±0.0692, 0.2783 ±0.1678, 0.1446 ±0.1528, 0.0315 ±0.0906, and 0.0419 ±0.1088 mm in rest, reciprocal arm tip, retentive arm tip, retentive arm shoulder, and reciprocal arm shoulder, respectively. The difference between titanium and CoCr alloys at each observation site was significant. CONCLUSION Clasps fabricated from titanium with SLM printing have the least deviation and better trueness compared to those fabricated from cobalt chromium.
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Zhang L, Yi Y, Ding L, Meng J, Wu G. Effect of Reinforcement Bar on Trueness of Printed Titanium Kennedy I Removable Partial Denture Frameworks by Selective Laser Melting. Int Dent J 2024:S0020-6539(24)00167-9. [PMID: 39034209 DOI: 10.1016/j.identj.2024.06.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 06/24/2024] [Accepted: 06/26/2024] [Indexed: 07/23/2024] Open
Abstract
OBJECTIVE The addition of reinforcement bars is a commonly used method to improve the fabrication trueness of selective laser melting removable partial denture alloy frameworks. However, the effects of different reinforcement bar designs on the trueness of the entire framework remain unclear. This study investigated the trueness of removable partial denture frameworks of pure titanium fabricated by selective laser melting under different reinforcement bar settings. METHOD A virtual framework was designed based on the Kennedy Class I partially edentulous model using computer-aided design software. Frameworks with different reinforcement bar settings (Ti-A without reinforcement bar, Ti-B with a single horizontal bar joining the lingual bar, Ti-C with two more bars at the anterior region, Ti-D with another horizontal bar at the anterior region, and Ti-E with one more bar at the posterior region, n = 5) were printed using pure titanium powder using a direct metal laser melting machine. The fabricated frameworks were scanned, and their fabrication trueness was compared with the designed virtual framework using one-way ANOVA. RESULTS The overall mean discrepancies for Ti-A, Ti-B, Ti-C, Ti-D, and Ti-E were 0.111, 0.047, 0.073, 0.068, and 0.047 mm, respectively. For the group of Ti-A set with no reinforcement bars, larger discrepancies were observed compared with the other four groups (P < .05). Groups Ti-B and Ti-E showed better trueness of the RPI clasps, rests, and distal ends (P < .05). CONCLUSIONS Adding reinforcement bars improved the printing trueness of the pure titanium frameworks, and different settings resulted in various degrees of improvement. Setting a single reinforcement bar to join the lingual bar or an additional reinforcement bar at the distal end significantly enhanced the printing trueness of the RPI clasps, rests, and distal ends.
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Affiliation(s)
- Li Zhang
- Nanjing Stomatological Hospital, Affiliated Stomatological Hospital of Medical School, Institute of Stomatology, Nanjing University, Nanjing, China
| | - Yingjie Yi
- Nanjing Stomatological Hospital, Affiliated Stomatological Hospital of Medical School, Institute of Stomatology, Nanjing University, Nanjing, China
| | - Ling Ding
- Nanjing Stomatological Hospital, Affiliated Stomatological Hospital of Medical School, Institute of Stomatology, Nanjing University, Nanjing, China
| | - Jiali Meng
- Nanjing Stomatological Hospital, Affiliated Stomatological Hospital of Medical School, Institute of Stomatology, Nanjing University, Nanjing, China
| | - Guofeng Wu
- Nanjing Stomatological Hospital, Affiliated Stomatological Hospital of Medical School, Institute of Stomatology, Nanjing University, Nanjing, China.
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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:S0022-3913(24)00434-7. [PMID: 38955601 DOI: 10.1016/j.prosdent.2024.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [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 S, Oh KC, Kim JH. Accuracy of Mandibular Removable Partial Denture Frameworks Fabricated by 3D Printing and Conventional Techniques. MATERIALS (BASEL, SWITZERLAND) 2024; 17:3148. [PMID: 38998231 PMCID: PMC11242778 DOI: 10.3390/ma17133148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Revised: 06/21/2024] [Accepted: 06/25/2024] [Indexed: 07/14/2024]
Abstract
Herein, we used digital superimposition to evaluate the accuracy of metal frameworks for mandibular removable partial dentures fabricated using three techniques. Thirty master casts of a mandibular dentiform were categorized into three groups (n = 10) based on the framework manufacturing method: selective laser melting-based metal three-dimensional (3D) printing (SLM), digital light projection-based resin 3D printing and subsequent casting (RPC), and conventional casting (CON). The master casts were scanned twice, initially after preparation and subsequently after attaching silicone using the frameworks. These scan files were digitally superimposed to measure the silicone thickness. Statistical analysis was conducted using SPSS Statistics (Version 23.0, IBM Corp., Somers, NY, USA). One-way ANOVA and a post hoc Tukey's multiple comparison tests were performed to determine differences among the three groups (α = 0.05). The RPC group exhibited significantly higher overall and mean internal discrepancies at rest and tissue stops than the SLM and CON groups, which exhibited statistically insignificant differences. Thus, SLM fabrication resulted in comparable accuracy to that achieved by CON, whereas sequentially performing resin 3D printing and casting induced inferior accuracy. However, all frameworks across the three groups were clinically acceptable.
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Affiliation(s)
- Soonam Kim
- Department of Dentistry, Graduate School, Yonsei University, Seoul 03722, Republic of Korea;
| | - Kyung Chul Oh
- Department of Prosthodontics, College of Dentistry, Yonsei University, Seoul 03722, Republic of Korea;
| | - Jee-Hwan Kim
- Department of Prosthodontics, College of Dentistry, Yonsei University, Seoul 03722, Republic of Korea;
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Yu X, Li J, Yu L, Wang Y, Gong Z, Pan J. A fully digital workflow for the design and manufacture of a class of metal orthodontic appliances. Heliyon 2024; 10:e32064. [PMID: 38867998 PMCID: PMC11168385 DOI: 10.1016/j.heliyon.2024.e32064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 05/06/2024] [Accepted: 05/28/2024] [Indexed: 06/14/2024] Open
Abstract
Background Traditional working procedures requires a lot of clinical processes and processing time. Methods The orthodontic metal appliances were made by applying oral scanners, digital images, computer-aided design and computer-aided manufacturing (CAD-CAM) printers. Results The computer digital technology simplified the manufacturing process for dental appliances and shorten the duration for clinical operation and technical processing. Conclusions The technique described in this paper can guarantee the accuracy of orthodontic appliances and bring revolution the field. Clinical significance The CAD-CAM technology provides a fully digital workflow for manufacturing metal orthodontic appliances, which saves a considerable amount of labor and material costs, and significantly reduces heavy metal pollution in the working environment of dental technicians.
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Affiliation(s)
- Xin Yu
- Department of Orthodontics Dentistry, Shanghai Stomatological Hospital & School of Stomatology, Fudan University, 356 East Beijing Rd, Shanghai, 200001, China
- Department of Preventive Dentistry, Shanghai Stomatological Hospital & School of Stomatology, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Fudan University, Shanghai, China
| | - Jiaxin Li
- Department of Preventive Dentistry, Shanghai Stomatological Hospital & School of Stomatology, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Fudan University, Shanghai, China
| | - Liming Yu
- Department of Orthodontics Dentistry, Shanghai Stomatological Hospital & School of Stomatology, Fudan University, 356 East Beijing Rd, Shanghai, 200001, China
- Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Fudan University, Shanghai, China
| | - Yuhui Wang
- Department of Orthodontics Dentistry, Shanghai Stomatological Hospital & School of Stomatology, Fudan University, 356 East Beijing Rd, Shanghai, 200001, China
- Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Fudan University, Shanghai, China
| | - Zhicheng Gong
- Department of Dental Laboratory Center, Shanghai Stomatological Hospital & School of Stomatology, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Fudan University, Shanghai, China
| | - Jie Pan
- Department of Orthodontics Dentistry, Shanghai Stomatological Hospital & School of Stomatology, Fudan University, 356 East Beijing Rd, Shanghai, 200001, China
- Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Fudan University, Shanghai, China
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Mani G, Porter D, Collins S, Schatz T, Ornberg A, Shulfer R. A review on manufacturing processes of cobalt-chromium alloy implants and its impact on corrosion resistance and biocompatibility. J Biomed Mater Res B Appl Biomater 2024; 112:e35431. [PMID: 38817036 DOI: 10.1002/jbm.b.35431] [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: 09/22/2023] [Revised: 03/23/2024] [Accepted: 05/13/2024] [Indexed: 06/01/2024]
Abstract
Cobalt-Chromium (CoCr) alloys are currently used for various cardiovascular, orthopedic, fracture fixation, and dental implants. A variety of processes such as casting, forging, wrought processing, hot isostatic pressing, metal injection molding, milling, selective laser melting, and electron beam melting are used in the manufacture of CoCr alloy implants. The microstructure and precipitates (carbides, nitrides, carbonitrides, and intermetallic compounds) formed within the alloy are primarily determined by the type of manufacturing process employed. Although the effects of microstructure and precipitates on the physical and mechanical properties of CoCr alloys are well reviewed and documented in the literature, the effects on corrosion resistance and biocompatibility are not comprehensively reviewed. This article reviews the various processes used to manufacture CoCr alloy implants and discusses the effects of manufacturing processes on corrosion resistance and biocompatibility. This review concludes that the microstructure and precipitates formed in the alloy are unique to the manufacturing process employed and have a significant impact on the corrosion resistance and biocompatibility of CoCr alloys. Additionally, a historical and scientific overview of corrosion and biocompatibility for metallic implants is included in this review. Specifically, the failure of CoCr alloys when used in metal-on-metal bearing surfaces of total hip replacements is highlighted. It is recommended that the type of implant/application (orthopedic, dental, cardiovascular, etc.) should be the first and foremost factor to be considered when selecting biomaterials for medical device development.
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Affiliation(s)
- Gopinath Mani
- Global Biocompatibility and Science & Technology Organization, Abbott, St. Paul, Minnesota, USA
| | - Deanna Porter
- Global Biocompatibility and Science & Technology Organization, Abbott, St. Paul, Minnesota, USA
| | - Shell Collins
- Global Biocompatibility and Science & Technology Organization, Abbott, St. Paul, Minnesota, USA
| | - Tim Schatz
- Global Biocompatibility and Science & Technology Organization, Abbott, St. Paul, Minnesota, USA
| | - Andreas Ornberg
- Global Biocompatibility and Science & Technology Organization, Abbott, St. Paul, Minnesota, USA
| | - Robert Shulfer
- Global Biocompatibility and Science & Technology Organization, Abbott, St. Paul, Minnesota, USA
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Lan D, Luo Y, Qu Y, Man Y. The three-dimensional stability and accuracy of 3D printing surgical templates: An In Vitro study. J Dent 2024; 144:104936. [PMID: 38492806 DOI: 10.1016/j.jdent.2024.104936] [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: 08/15/2023] [Revised: 02/23/2024] [Accepted: 03/10/2024] [Indexed: 03/18/2024] Open
Abstract
OBJECTIVE To evaluate the three-dimensional (3D) stability and accuracy of additively manufactured surgical templates fabricated using two different 3D printers and materials. MATERIALS AND METHODS Forty surgical templates were designed and printed using two different 3D printers: the resin group (n = 20) used a digital light processing (DLP) 3D printer with photopolymer resin, and the metal group (n = 20) employed a selective laser melting (SLM) 3D printer with titanium alloy. All surgical templates were scanned immediately after production and re-digitalized after one month of storage. Similarly, the implant simulations were performed twice. Three-dimensional congruency between the original design and the manufactured surgical templates was quantified using the root mean square (RMS), and the definitive and planned implant positions were determined and compared. RESULTS At the postproduction stage, the metal templates exhibited higher accuracy than the resin templates (p < 0.001), and these differences persisted after one month of storage (p < 0.001). The resin templates demonstrated a significant decrease in three-dimensional stability after one month of storage (p < 0.001), whereas the metal templates were not affected (p > 0.05). No significant differences in implant accuracy were found between the two groups. However, the resin templates showed a significant increase in apical and angular deviations after one month of storage (p < 0.001), whereas the metal templates were not affected (p > 0.05). CONCLUSION Printed metal templates showed higher fabrication accuracy than printed resin templates. The three-dimensional stability and implant accuracy of printed metal templates remained unaffected by one month of storage. CLINICAL SIGNIFICANCE With superior three-dimensional stability and acceptable implant accuracy, printed metal templates can be considered a viable alternative technique for guided surgery.
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Affiliation(s)
- Dongping Lan
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Oral Implantology, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China
| | - Yilin Luo
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Oral Implantology, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China
| | - Yili Qu
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China
| | - Yi Man
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases & Department of Oral Implantology, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China.
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Vohra F, Alsaif R, Khan R, Bukhari IA. Comparison of De-Torque and Failure Load Evaluation of Selective-Laser-Sintered CoCr, CAD-CAM ZrO, and Machined Implant Abutment/Restoration. Bioengineering (Basel) 2024; 11:448. [PMID: 38790315 PMCID: PMC11118100 DOI: 10.3390/bioengineering11050448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/16/2024] [Accepted: 04/18/2024] [Indexed: 05/26/2024] Open
Abstract
AIM This study aimed to compare the torque loss, fracture load, compressive strength, and failure types of selective-laser-sintered cobalt chromium (SLM-Co-Cr), computer-aided design and computer-aided manufacturing zirconium oxide (CAD-CAM-ZrO), and machined titanium (Ti) implant abutments. METHODS Thirty endosseous dental implants were vertically embedded with machined Ti (control group), CAD-CAM-ZrO, and SLM-Co-Cr abutments. Abutment fabrication involved CAD-CAM milling and SLM technology. The de-torque assessment included preload reverse torque values (RTVs), cyclic loading, and post-RTVs using a customized protocol. Fracture load assessment employed ISO-14801 standards, and statistical analysis was conducted using ANOVA and Tukey Post hoc tests (p < 0.05). RESULTS In pre-load RTVs, SLM-Co-Cr showed the lowest mean torque loss (24.30 ± 2.13), followed by machined Ti (27.33 ± 2.74) and CAD-CAM-ZrO (22.07 ± 2.20). Post-load RTVs decreased for all groups. Fracture load and compressive strength were highest for SLM-Co-Cr, with significant differences among groups (p < 0.001). Fracture types included abutment failures in SLM-Co-Cr and machined Ti, while CAD-CAM-ZrO exhibited crown separation with deformation. CONCLUSION SLM-Co-Cr-fabricated implant abutments exhibited superior stability and resistance to rotational forces, higher fracture loads, and greater compressive strength compared to CAD-CAM-ZrO and machined Ti.
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Affiliation(s)
- Fahim Vohra
- Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh 12485-6541, Saudi Arabia;
| | - Rawan Alsaif
- Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh 12485-6541, Saudi Arabia;
| | - Rawaiz Khan
- Engineer Abdullah Bugshan Research Chair for Dental and Oral Rehabilitation, College of Dentistry, King Saud University, Riyadh 12485-6541, Saudi Arabia;
| | - Ishfaq A. Bukhari
- Department of Pharmacology, College of Medicine, King Saud University, Riyadh 12485-6541, Saudi Arabia;
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Daou EE. Effect of lamination layer thickness and abutment preparation on the fit of Co-Cr multi-unit prostheses fabricated by additive manufacturing: An in vitro study. J Prosthet Dent 2024; 131:652-657. [PMID: 35430049 DOI: 10.1016/j.prosdent.2022.02.005] [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: 07/05/2021] [Revised: 02/04/2022] [Accepted: 02/04/2022] [Indexed: 11/19/2022]
Abstract
STATEMENT OF PROBLEM Selective laser melting has been increasingly used in the fabrication of metal-ceramic prostheses. The lamination layer thickness may influence the fit of the restoration. However, data regarding its impact remain scarce. PURPOSE The purpose of this in vitro study was to evaluate the marginal and internal fit of cobalt-chromium (Co-Cr) 3-unit frameworks fabricated by additive manufacturing with different melting layer thicknesses on different abutments. MATERIAL AND METHODS The first right maxillary premolar and molar from a typodont were prepared with a circumferential 1.2-mm chamfer, 2-mm occlusal reduction, and total taper of 8 degrees to receive 3-unit fixed partial dentures. After framework design, the data were sent to a laser machine, and 30 specimens were fabricated from Co-Cr metal powder (Mediloy S-Co) by selective laser melting. Specimens were assigned to 3 groups (n=10) with different lamination layer thicknesses of 25 (L25), 50 (L50), and 100 (L100) μm. Marginal fit and internal fit were evaluated. Results were compared among layer thickness groups and abutments. Data were compared by using the Levene test, t test, and ANOVA (α=.05). RESULTS A statistical difference was found between different layer thickness groups (P=.016), but not between abutments (P=.429). On the abutment level, significant difference was found in the gap values for the molars (P=.049) between layer thickness groups, but not for the premolars (P=.126). Group L25 reported the smallest mean discrepancy values, and group L100 reported the highest, with statistical difference found between group L100 and groups L25 (P<.001) and L50 (P<.025), but not between groups L25 and L50 (P=.094). CONCLUSIONS The lamination layer thickness affected the adaptation of the metal frameworks. Framework fit did not significantly differ between abutments.
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Affiliation(s)
- Elie E Daou
- Assistant Professor, Department of Prosthodontics, School of Dentistry, Lebanese University, Beirut, Lebanon; Assistant Professor, Al-Ayen University, Nile Street, Nasiriyah.
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Mohammed AJ, Al-Ali AA. The role of internal architecture in producing high-strength 3D printed cobalt-chromium objects. J Adv Prosthodont 2024; 16:91-104. [PMID: 38694190 PMCID: PMC11058351 DOI: 10.4047/jap.2024.16.2.91] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 02/10/2024] [Accepted: 02/25/2024] [Indexed: 05/04/2024] Open
Abstract
PURPOSE The objectives of the current study were to estimate the influence of self-reinforced hollow structures with a graded density on the dimensional accuracy, weight, and mechanical properties of Co-Cr objects printed with the direct metal laser sintering (DMLS) technique. MATERIALS AND METHODS Sixty-five dog-bone samples were manufactured to evaluate the dimensional accuracy of printing, weight, and tensile properties of DMLS printed Co-Cr. They were divided into Group 1 (control) (n = 5), Group 2, 3, and 4 with incorporated hollow structures based on (spherical, elliptical, and diamond) shapes; they were subdivided into subgroups (n = 5) according to the volumetric reduction (10%, 15%, 20% and 25%). Radiographic imaging and microscopic analysis of the fractographs were conducted to validate the created geometries; the dimensional accuracy, weight, yield tensile strength, and modulus of elasticity were calculated. The data were estimated by one-way ANOVA and Duncan's tests at P < .05. RESULTS The accuracy test showed an insignificant difference in the x, y, z directions in all printed groups. The weight was significantly reduced proportionally to the reduced volume fraction. The yield strength and elastic modulus of the control group and Group 2 at 10% volume reduction were comparable and significantly higher than the other subgroups. CONCLUSION The printing accuracy was not affected by the presence or type of the hollow geometry. The weight of Group 2 at 10% reduction was significantly lower than that of the control group. The yield strength and elastic modulus of the Group 2 at a 10% reduction showed means equivalent to the compact objects and were significantly higher than other subgroups.
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Affiliation(s)
| | - Ahmed Asim Al-Ali
- Department of Prosthodontics, College of Dentistry, Mosul University, Mosul, Iraq
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Lekatou AG, Emmanouilidou S, Dimitriadis K, Baikousi M, Karakassides MA, Agathopoulos S. Simulating porcelain firing effect on the structure, corrosion and mechanical properties of Co-Cr-Mo dental alloy fabricated by soft milling. Odontology 2024; 112:372-389. [PMID: 37642767 PMCID: PMC10925571 DOI: 10.1007/s10266-023-00849-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 08/18/2023] [Indexed: 08/31/2023]
Abstract
This study aims at evaluating the effect of simulating porcelain firing on the microstructure, corrosion behavior and mechanical properties of a Co-Cr-Mo alloy fabricated by Metal Soft Milling (MSM). Two groups of Co-28Cr-5Mo specimens (25 × 20 × 3 mm) were prepared by MSM: The as-sintered (AS) specimens and the post-fired (PF) specimens that were subjected to 5 simulating porcelain firing cycles without applying the ceramic mass onto their surface. Phase identification by X-ray Diffraction (XRD), microstructure examination by optical microscopy and Scanning Electron Microscopy combined with Energy-Dispersive X-ray Spectroscopy (SEM/EDX), corrosion testing by cyclic polarization and chronoamperometry in simulated body fluid (SBF), the latter test accompanied by Cr3+ and Cr6+ detection in the electrolyte through the 1.5-diphenylcarbazide (DPC) method and UV/visible spectrophotometry, and mechanical testing by micro-/nano-indentation were conducted to evaluate the effect of the post-firing cycles on the properties of Co-Cr-Mo. The results were statistically analyzed by the t test (p < 0.05: statistically significant). All specimens had a mixed γ-fcc and ε-hcp cobalt-based microstructure with a dispersion of pores filled with SiO2 and a fine M23C6 intergranular presence. PF led to an increase in the ε-Co content and slight grain coarsening. Both AS and PF alloys showed high resistance to general and localized corrosion, whereas neither Cr6+ nor Cr3+ were detected during the passivity-breakdown stage. PF improved the mechanical properties of the AS-alloy, especially the indentation modulus and true hardness (statistically significant differences: p = 0.0009 and 0.006, respectively). MSM and MSM/simulating-porcelain firing have been proven trustworthy fabrication methods of Co-Cr-Mo substrates for metal-ceramic prostheses. Moreover, the post-firing cycles improve the mechanical behavior of Co-Cr-Mo, which is vital under the dynamically changing loads in the oral cavity, whereas they do not degrade the corrosion performance.
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Affiliation(s)
- Angeliki G Lekatou
- Department of Materials Science and Engineering, School of Engineering, University of Ioannina, 451 10, Ioannina, Greece
- Institute of Materials Science and Computing, University Research Center of Ioannina (URCI), 451 10, Ioannina, Greece
| | - Sevasti Emmanouilidou
- Department of Materials Science and Engineering, School of Engineering, University of Ioannina, 451 10, Ioannina, Greece
| | - Konstantinos Dimitriadis
- Department of Materials Science and Engineering, School of Engineering, University of Ioannina, 451 10, Ioannina, Greece.
- Division of Dental Technology, Department of Biomedical Sciences, University of West Attica, 122 43, Athens, Greece.
| | - Maria Baikousi
- Department of Materials Science and Engineering, School of Engineering, University of Ioannina, 451 10, Ioannina, Greece
| | - Michael A Karakassides
- Department of Materials Science and Engineering, School of Engineering, University of Ioannina, 451 10, Ioannina, Greece
| | - Simeon Agathopoulos
- Department of Materials Science and Engineering, School of Engineering, University of Ioannina, 451 10, Ioannina, Greece
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Klimek L, Bułhak B, Śmielak B. A Comparison of the Structure and Selected Mechanical Properties of Cr/Co Alloys Obtained by Casting and Selective Laser Melting. J Funct Biomater 2024; 15:61. [PMID: 38535254 PMCID: PMC10970936 DOI: 10.3390/jfb15030061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 02/09/2024] [Accepted: 02/23/2024] [Indexed: 06/27/2024] Open
Abstract
Selective laser melting (SLM) technologies are becoming increasingly popular. The aim of the work is to compare the metallographic structure, hardness, and selected strength properties of alloys obtained by casting and by SLM, with a particular emphasis on fatigue strength. Twenty Cr/Co alloy bars were made by casting or SLM, and samples of appropriate dimensions were prepared for individual tests. The microstructures of the samples were tested by metallography, and then tested for hardness, impact strength, tensile strength, bending strength, and fatigue strength; they were also subjected to fracture after bending, tensile, fatigue, and impact tests, with the resulting fractures examined by scanning electron microscopy (SEM). Primary dendrites and small amounts of gas bubbles were present in the cast samples ground lengthwise. The SEM samples were more finer grained and uniform. Compared to the casting samples, the SLM samples demonstrated higher hardness, lower mean impact strength and higher tensile strength. The casting samples also displayed lower mean elongation values. The casting samples demonstrated slightly higher fatigue strength. The fractures of the casting samples showed an interdendritic character with clearly visible dendrites at the fracture, while those of the SLM samples were also intergranular, but finer grained. SLM generally results in better strength properties, while casting obtains slightly greater fatigue strength.
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Affiliation(s)
- Leszek Klimek
- Institute of Materials Science and Engineering, Lodz University of Technology, 90-924 Lodz, Poland;
| | - Barbara Bułhak
- Department of Dental Techniques, Medical University of Lodz, ul. Pomorska 251, 92-231 Lodz, Poland;
| | - Beata Śmielak
- Department of Prosthodontics, Medical University of Lodz, ul. Pomorska 251, 92-231 Lodz, Poland
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Rathee M, Divakar S, Jain P, Singh S, Chahal S. Prosthetic rehabilitation of mucormycosis patients using DMLS fabricated cast partial denture with semi-precision attachments-A case series. SPECIAL CARE IN DENTISTRY 2024; 44:478-485. [PMID: 37431228 DOI: 10.1111/scd.12902] [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: 04/03/2023] [Revised: 06/15/2023] [Accepted: 06/27/2023] [Indexed: 07/12/2023]
Abstract
BACKGROUND The rehabilitation of maxillectomy defects is a challenging endeavour that necessitates customizing the procedure for each patient. The successful treatment for these patients requires a combined conventional and contemporary treatment options. The high-tech prosthodontic treatment option for these defects and distal extension cases are combining fixed and removable partial dentures with precision/semi-precision attachments. It will enhance retention, stability, esthetics and functional ability of the prosthesis. METHODS Three post-Covid Mucormycosis patients reported after localised debridement and partial maxillectomy for definitive rehabilitation. For partial Maxillectomy patients, DMLS designed cast partial denture along with semi-precision attachments (Preci-vertix and OT strategy Rhein For patient with localized defect, DMLS designed cast partial denture was planned. For both patients the defect area was kept as hollow cavity (Closed or Open), in order to reduce the weight of the prosthesis. RESULTS AND CONCLUSION The prosthodontic rehabilitation of these patient can be a simple and economical treatment options and it improves the stomatognathic functions and quality of life of the patient. The major hurdles during rehabilitation are retention and stability as there is no basal seat and hard tissue support. Hence, we tried a combined conventional and digital techniques in order to provide prosthesis with precise fit and accuracy as well as reducing the treatment time and visits of the patients.
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Affiliation(s)
- Manu Rathee
- Department of Prosthodontics, Post Graduate Institute of Dental Sciences, Rohtak, Haryana, India
| | - Santhanam Divakar
- Department of Prosthodontics, Post Graduate Institute of Dental Sciences, Rohtak, Haryana, India
| | - Prachi Jain
- Post Graduate Institute of Dental Sciences, PT. B.D. Sharma University of Health Sciences, Rohtak, Haryana, India
| | - Sandeep Singh
- Department of Prosthodontics, Post Graduate Institute of Dental Sciences, Rohtak, Haryana, India
| | - Sujata Chahal
- Department of Prosthodontics, Post Graduate Institute of Dental Sciences, Rohtak, Haryana, India
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17
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Lee CG, Jin G, Lim JH, Liu Y, Afrashtehfar KI, Kim JE. Influence of hydrothermal aging on the shear bond strength of 3D printed denture-base resin to different relining materials. J Mech Behav Biomed Mater 2024; 149:106221. [PMID: 37976994 DOI: 10.1016/j.jmbbm.2023.106221] [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: 09/19/2023] [Revised: 10/31/2023] [Accepted: 11/03/2023] [Indexed: 11/19/2023]
Abstract
OBJECTIVES This study evaluated the repairability of three-dimensional printed (3DP) denture bases based on different conventional relining materials and aging. MATERIAL AND METHODS The groups for surface characterization (surface-roughness and contact-angle measurements) were divided based on the denture base and surface treatment. Shear bond strength test and failure-mode analysis were conducted by a combination of three variables: denture base, relining materials, and hydrothermal aging (HA). The initial characterization involved quantifying the surface roughness (n = 10) and contact angle (n = 10) of denture base specimens with and without sandblasting (SB) treatment. Four relining materials (Kooliner [K], Vertex Self-Curing [V], Tokuyama Rebase II (Normal) [T], and Ufi Gel Hard [U]) were applied to 3DP, heat-cured (HC), and self-cured (SC) denture-base resin specimens. Shear bond strength (n = 15) and failure-mode analyses (n = 15) were performed before and after HA, along with evaluations of the fractured surfaces (n = 4). Statistical analyses were performed using a two-way analysis of variance (ANOVA) for surface characterization, and a three-way ANOVA was conducted for shear bond strength. RESULTS The surface roughness peaked in HC groups and increased after SB. The 3DP group displayed significantly lower contact angles, which increased after treatment, similar to the surface roughness. The shear bond strength was significantly lower for 3DP and HC denture bases than for SC denture bases, and peaked for U at 10.65 ± 1.88 MPa (mean ± SD). HA decreased the shear bond strength relative to untreated samples. Furthermore, 3DP, HC, and SC mainly showed mixed or cohesive failures with V, T, and U. K, on the other hand, trended toward adhesive failures when bonded with HC and SC. CONCLUSION This study has validated the repairability of 3DP dentures through relining them with common materials used in clinical practice. The repairability of the 3DP denture base was on par with that of conventional materials, but it decreased after aging. Notably, U, which had a postadhesive application, proved to be the most effective material for repairing 3DP dentures.
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Affiliation(s)
- Chan-Gyu Lee
- Department of Prosthodontics, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea; Oral Science Research Center, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
| | - Gan Jin
- Department of Prosthodontics, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea; Oral Science Research Center, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
| | - Jung-Hwa Lim
- Department of Prosthodontics, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
| | - Yunqi Liu
- Department of Prosthodontics, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea; Oral Science Research Center, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
| | - Kelvin I Afrashtehfar
- Division of Restorative Dental Sciences, College of Dentistry, Ajman University, University Street, Al Jerf 1, 346 Ajman, United Arab Emirates; Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Freiburgstrasse 7, 3010, Bern, Switzerland; Department of Operative Dentistry, Periodontology and Preventive Dentistry, RWTH Aachen University Hospital, Pauwelsstrasse 30, 52074, Aachen, Germany.
| | - Jong-Eun Kim
- Department of Prosthodontics, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
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El Charkawi HG, Abdelaziz MS. Novel CAD-CAM fabrication of a custom-made ball attachment retentive housing: an in-vitro study. Eur J Med Res 2023; 28:520. [PMID: 37968756 PMCID: PMC10652503 DOI: 10.1186/s40001-023-01498-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 11/02/2023] [Indexed: 11/17/2023] Open
Abstract
PURPOSE This study aims to evaluate the digitally designed ball attachment housing in its initial retentive force and after 2 years of simulated clinical use and to compare it with the regular nylon ball attachment housing. MATERIALS AND METHODS Twenty implants with their corresponding ball abutments (diameter 4.5 × 4.0 mm) were inserted in resin blocks. They were divided into two groups. In Group I, ten ball abutments each received their corresponding conventional attachment with nylon rings. In Group II, ten ball abutments received the novel CAD-CAM polyetheretherketone ball attachment housing. A universal testing machine was used to measure the retention force. The achieved maximum values of retention force were recorded at the beginning of the study (initial retention) and after 2 years of artificial ageing (2000 cycles of insertion and removal). Results were statistically analyzed using an independent sample T test. RESULTS The PEEK attachment housing showed high retention forces (25.12 ± 0.99 N) compared to the conventional attachment with a nylon ring (15.76 ± 0.93 N) in the initial dislodgement test. There was a statistically significant difference in mean retention at the initial retention test and after 2 years of stimulated usage between the two studied groups, p = 0.000. CONCLUSIONS Within the limitations of this study, the novel CAD-CAM-PEEK attachment showed high retention characteristics compared to the conventional attachment with nylon rings, initially and after simulated long-term use.
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Affiliation(s)
- Hussein G El Charkawi
- Department of Prosthodontics, Faculty of Oral and Dental Medicine, Future University, Fifth Settlement, End of 90 Street, Cairo, Egypt.
| | - Medhat Sameh Abdelaziz
- Department of Prosthodontics, Faculty of Oral and Dental Medicine, Future University, Fifth Settlement, End of 90 Street, Cairo, Egypt
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Dolfini Alexandrino L, Martinez Antunes LH, Jardini Munhoz AL, Ricomini Filho AP, da Silva WJ. Mechanical and surface properties of Co-Cr alloy produced by additive manufacturing for removable partial denture frameworks. J Prosthet Dent 2023; 130:780-785. [PMID: 35184888 DOI: 10.1016/j.prosdent.2021.12.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 12/13/2021] [Accepted: 12/13/2021] [Indexed: 11/20/2022]
Abstract
STATEMENT OF PROBLEM Conventional analog methods have been replaced with digital methods for removable partial denture (RPD) frameworks. However, limited information is available regarding the build direction of RPD frameworks and its effect on properties. PURPOSE The purpose of this in vitro study was to evaluate the mechanical and surface properties of the cobalt chromium (Co-Cr) alloy produced at different build angles by the laser powder bed fusion additive manufacturing (AM) technology used for RPD framework fabrication. MATERIAL AND METHODS Plate-shaped Co-Cr specimens (n=6) were produced by the AM technology and divided into 3 groups depending on the build angle (0, 45, or 90 degrees). The elastic modulus and fracture properties were evaluated by flexural testing. Additionally, 15 disks were printed by using the same parameters of the plates (n=5) to analyze the surface hardness with microhardness testing, and surface properties were determined by surface free energy by using the contact angle and surface roughness measured by using a profilometer. Twelve Co-Cr cylindrical specimens were produced by using the same parameters (n=4), and their microstructure was examined by using an optical microscope. One-way ANOVA was used to evaluate the overall effects of the interaction between groups, and the Tukey test was applied when the interaction was statistically significant (α=.05). RESULTS The flexural strength showed a statistically significant difference (P<.05), with the peak value exhibited by the 0-degree group. A statistical difference was also observed between the angulation and modulus of elasticity; however, the highest value was exhibited by the 45-degree group. For the fracture topography, all groups observed a dimple-like fracture, although the 45-degree group showed wider cleavage planes of fractures than other angulations. For microhardness, the 0- and 45-degree groups exhibited a statistical difference in relation to the 90-degree group (P<.05). For surface properties, no statistically significant difference (P>.05) was found in any of the evaluated parameters. Dependence on the build angles was evidenced by the molten pool boundaries during observation of the microstructure. CONCLUSIONS The build angle influenced the flexural strength and microhardness of the Co-Cr alloy produced by AM; however, it does not affect surface free energy and surface roughness.
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Affiliation(s)
- Larissa Dolfini Alexandrino
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, SP, Brazil
| | | | - André Luiz Jardini Munhoz
- National Institute of Biofabrication, School of Chemical Engineering, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Antônio Pedro Ricomini Filho
- Department of Physiological Sciences, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, SP, Brazil
| | - Wander José da Silva
- Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Piracicaba, SP, Brazil.
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Albayrak H, Ayata M, Demirel B. Recycling selective laser melting alloy powder on cobalt chromium-to-ceramic bond strength. J Prosthet Dent 2023; 130:786.e1-786.e7. [PMID: 37718178 DOI: 10.1016/j.prosdent.2023.08.008] [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: 04/20/2023] [Revised: 08/04/2023] [Accepted: 08/09/2023] [Indexed: 09/19/2023]
Abstract
STATEMENT OF PROBLEM Reusing the powder in selective laser melting machines after multiple cycles is a cost-effective procedure for dental laboratories. However, information on the metal-ceramic bond strength of the framework fabricated by using recycled powder is lacking. PURPOSE The purpose of this in vitro study was to investigate how the bonding agent and repeated alloy powder reuse affected the metal-ceramic bond strength of cobalt chromium frameworks fabricated by using selective laser melting. MATERIAL AND METHODS Four square and 40-bar-shaped cobalt chromium frameworks were fabricated by selective laser melting. Half were produced by using virgin alloy powder (Group V; nsquare=2, nbar=20), and half with 30-times reused powder (Group R; nsquare=2, nbar=20). The particle size of each powder was measured by using scanning electron microscopy, and its phase composition was characterized by using radiograph diffraction. Each group was divided into 2 subgroups (Group W [Wash Opaque] and Group N [NP-Bond]) according to the brand of bonding agent used. After ceramic application, the metal-ceramic bond strengths were evaluated by using 3-point bend tests. The bonding agents' chemical composition was analyzed by using radiograph fluorescence. Bond strength data were analyzed by using a 2-way analysis of variance (α=.05). RESULTS Mean ±standard deviation bond strengths did not differ significantly (P>.05) between Groups V (31.25 ±4.65) and R (30.88 ±4.78). Group W (35.34 ±1.78) had significantly higher bond strength than Group N (26.80 ±1.74; P<.001). Radiograph diffraction analysis found that the phase composition of all powders was similar. The bonding agent in Group W contained cerium, whereas, that in Group N did not. CONCLUSIONS Metal-ceramic bond strength was unaffected by alloy powder reuse. However, the bonding agent brand may affect the bond strength of cobalt chromium frameworks fabricated by using selective laser melting.
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Affiliation(s)
- Haydar Albayrak
- Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey
| | - Mustafa Ayata
- Private practice, Dentos Oral and Dental Health Polyclinic, Kayseri, Turkey.
| | - Bilal Demirel
- Professor, Department of Material Science and Engineering, Faculty of Engineering, Erciyes University, Kayseri, Turkey
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Giti R, Hosseinpour Aghaei M, Mohammadi F. The effect of repeated porcelain firings on the marginal fit of millable and conventional casting alloys. PLoS One 2023; 18:e0275374. [PMID: 37874843 PMCID: PMC10597472 DOI: 10.1371/journal.pone.0275374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 09/15/2022] [Indexed: 10/26/2023] Open
Abstract
The durability of dental restorations is highly determined by an accurate marginal fit, which is in turn affected by the high temperature of porcelain firing. Information is inadequate about the marginal adaptation of metal-ceramic restorations fabricated by soft metal milling technologies after repeated firings. This study aimed to compare the effect of repeated ceramic firings on the marginal fit of copings fabricated from cobalt-chromium through soft metal milling and a conventional nickel-chromium casting alloy. A single standard brass die was designed, machined, and scanned, based on which, 20 frameworks were designed and fabricated through either soft metal milling or conventional casting (n = 10 per group) and porcelain veneered. The vertical marginal fit of the metal copings was measured after 3, 5, and 7 firing cycles by using a digital microscope on 16 points around the finish line of the metal die at ×80 magnification. The data were analyzed through repeated measures ANOVA and independent t-test (α = 0.05). The marginal fit of neither metal group was significantly affected by the number of firing cycles (P = 0.747). However, the marginal discrepancy was statistically lower in the soft metal milling group than that in the casting group (P<0.001). Repeated porcelain firings did not significantly affect the marginal fit of either alloy and remained within the clinically acceptable range after firings. However, the milled alloy had superior marginal fit regardless of the number of firing cycles.
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Affiliation(s)
- Rashin Giti
- Department of Prosthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Fars, Iran
| | - Mahdi Hosseinpour Aghaei
- Student Research Committee, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Fars, Iran
| | - Farhad Mohammadi
- Department of Pharmaceutics, School of Pharmacy, Shahid Sadoughi University of Medical Sciences and Health Care Services, Yazd, Iran
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Rahmani R, Lopes SI, Prashanth KG. Selective Laser Melting and Spark Plasma Sintering: A Perspective on Functional Biomaterials. J Funct Biomater 2023; 14:521. [PMID: 37888186 PMCID: PMC10607885 DOI: 10.3390/jfb14100521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/09/2023] [Accepted: 10/14/2023] [Indexed: 10/28/2023] Open
Abstract
Achieving lightweight, high-strength, and biocompatible composites is a crucial objective in the field of tissue engineering. Intricate porous metallic structures, such as lattices, scaffolds, or triply periodic minimal surfaces (TPMSs), created via the selective laser melting (SLM) technique, are utilized as load-bearing matrices for filled ceramics. The primary metal alloys in this category are titanium-based Ti6Al4V and iron-based 316L, which can have either a uniform cell or a gradient structure. Well-known ceramics used in biomaterial applications include titanium dioxide (TiO2), zirconium dioxide (ZrO2), aluminum oxide (Al2O3), hydroxyapatite (HA), wollastonite (W), and tricalcium phosphate (TCP). To fill the structures fabricated by SLM, an appropriate ceramic is employed through the spark plasma sintering (SPS) method, making them suitable for in vitro or in vivo applications following minor post-processing. The combined SLM-SPS approach offers advantages, such as rapid design and prototyping, as well as assured densification and consolidation, although challenges persist in terms of large-scale structure and molding design. The individual or combined application of SLM and SPS processes can be implemented based on the specific requirements for fabricated sample size, shape complexity, densification, and mass productivity. This flexibility is a notable advantage offered by the combined processes of SLM and SPS. The present article provides an overview of metal-ceramic composites produced through SLM-SPS techniques. Mg-W-HA demonstrates promise for load-bearing biomedical applications, while Cu-TiO2-Ag exhibits potential for virucidal activities. Moreover, a functionally graded lattice (FGL) structure, either in radial or longitudinal directions, offers enhanced advantages by allowing adjustability and control over porosity, roughness, strength, and material proportions within the composite.
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Affiliation(s)
- Ramin Rahmani
- CiTin—Centro de Interface Tecnológico Industrial, 4970-786 Arcos de Valdevez, Portugal;
- proMetheus, Instituto Politécnico de Viana do Castelo (IPVC), 4900-347 Viana do Castelo, Portugal
| | - Sérgio Ivan Lopes
- CiTin—Centro de Interface Tecnológico Industrial, 4970-786 Arcos de Valdevez, Portugal;
- ADiT-Lab, Instituto Politécnico de Viana do Castelo (IPVC), 4900-347 Viana do Castelo, Portugal
| | - Konda Gokuldoss Prashanth
- Department of Mechanical and Industrial Engineering, Tallinn University of Technology, 19086 Tallinn, Estonia;
- CBCMT, School of Mechanical Engineering, Vellore Institute of Technology, Vellore 630014, Tamil Nadu, India
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Tarek Ahmed S, Assery MK, Suganna M, Kausher H, Meer Rownaq Ali AB, Fadel Aldawsari H. A Feasible and Innovative Method of Investing Wax Pattern for Removable Partial Dentures: An In Vitro Study. Cureus 2023; 15:e46447. [PMID: 37927738 PMCID: PMC10622851 DOI: 10.7759/cureus.46447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 10/03/2023] [Indexed: 11/07/2023] Open
Abstract
Background A dental prosthesis called a removable partial denture (RPD) is used to fill the gaps left by one or more lost teeth. It serves as an option to fixed bridges and restorations supported by implants. This research was on a simple and effective method of investing RPD wax pattern and an in vitro investigation into the creation of a cutting-edge RPD technique. Methodology The method outlines the straightforward steps for waxing an RPD and validating the precision of the cast framework. The use of a laminated paper ring rather than a metallic one for investing the wax patterns is the main distinction between the novel method and the traditional ringless technique. Results A total of 30 samples were considered for investigation, with 15 in the traditional and 15 in the experimental group. The innovative wax pattern investment method exhibited a higher mean geometric orientation (9.23 ± 0.42) compared to traditional investment casting (8.90 ± 0.37 mm). Conversely, the dimensional accuracy mean was lower for the innovative wax pattern investment method (0.28 ± 0.03 mm) compared to traditional investment casting (0.31 ± 0.05 mm). The p-value was less than 0.001 for both parameters, signifying that the differences between the means of the two methods were statistically significant. The statistical power (1-β) was the probability of rejecting the null hypothesis when it was false. The statistical power was 0.999 for both geometric orientation and dimensional accuracy, indicating that the study had a very high power to detect differences between the two methods. Conclusions This innovative method does away with the requirement for a commercially available plastic ring, reduces the price and time needed for RPD manufacturing, and offers decent marginal accuracy. However, it has some restrictions, such as the challenge of cutting and preparing the paper ring after investing, which could lower the finished product's quality.
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Affiliation(s)
- Sara Tarek Ahmed
- Department of Prosthodontics, College of Dentistry, Riyadh Elm University, Riyadh, SAU
| | - Mansour K Assery
- Department of Prosthodontics, Riyadh Elm University, Riyadh, SAU
| | - Mahesh Suganna
- Department of Prosthodontics, Riyadh Elm University, Riyadh, SAU
| | - Hina Kausher
- Department of Prosthodontics, Dental Lab Technology, College of Applied Medical Sciences, Riyadh Elm University, Riyadh, SAU
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Heiba IM, Mohamed Lotfy S, Rizk FN, Sabet ME. Effect of different digital technology on the adaptation and retention of Co-Cr partial denture frameworks. J Prosthodont 2023. [PMID: 37688449 DOI: 10.1111/jopr.13765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 09/06/2023] [Indexed: 09/10/2023] Open
Abstract
PURPOSE To evaluate the overall adaptation and retention of class I cobalt-chromium (Co-Cr) removable partial denture (RPD) frameworks using three different computer-aided design and computer-aided manufacturing (CAD-CAM) technologies: Indirect wax milling with lost wax technique (LWT), direct milling, and selective laser melting (SLM) technique. MATERIALS AND METHODS An educational maxillary stone model (Kennedy class I) was scanned after preparing rest seats to create a resin model. The resin model was scanned, and the RPD framework was digitally designed and saved as a standard tessellation language (STL) file. Twenty-four Co-Cr RPD frameworks were then constructed and divided into three groups (n = 8) based on fabrication technique: Group A (indirect wax milling with LWT), Group B (direct milling), and Group C (selective laser melting). In Group A, the STL file was used to mill the design from castable resin blanks which were then cast by the LWT. In Group B, the STL file was used to mill the design from the Co-Cr blank directly. Finally in Group C, the STL file was used to print the design from Co-Cr powder using SLM 3D printed technique. Geomagic Control X software was used to measure the overall adaptation of the fabricated RPD frameworks, Retention was also tested using a universal testing machine. One-way Analysis of Variance (ANOVA) test was used to compare the three groups then the Tukey HSD post-hoc test was used for pair-wise comparisons. The significance level was set at p ≤ 0.05. RESULTS Regarding the overall adaptation, Group B (0.71 ± 0.02 mm) showed significantly higher adaptation than Group A (0.96 ± 0.06 mm) and Group C (1.05 ± 0.16 mm). Regarding retention, Group B (2.03 ± 0.34 N) showed significantly higher retention than Group A (1.00 ± 0.13 N) and Group C (0.78 ±0.17 N). CONCLUSION Based on the findings of this in vitro study, Co-Cr RPD frameworks fabricated by direct milling technique revealed the best adaptation and retention.
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Affiliation(s)
- Islam Mohamed Heiba
- Department of Oral and Maxillofacial Prosthodontics, Faculty of Dentistry, British University in Egypt, Cairo, Egypt
| | - Shaimaa Mohamed Lotfy
- Department of Oral and Maxillofacial Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt
| | - Fardos Nabil Rizk
- Department of Oral and Maxillofacial Prosthodontics, Faculty of Dentistry, British University in Egypt, Cairo, Egypt
| | - Marwa Ezzat Sabet
- Department of Oral and Maxillofacial Prosthodontics, Faculty of Dentistry, Ain Shams University, Cairo, Egypt
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Liang W, Zhou C, Zhang H, Bai J, Jiang B, Jiang C, Ming W, Zhang H, Long H, Huang X, Zhao J. Recent advances in 3D printing of biodegradable metals for orthopaedic applications. J Biol Eng 2023; 17:56. [PMID: 37644461 PMCID: PMC10466721 DOI: 10.1186/s13036-023-00371-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 07/31/2023] [Indexed: 08/31/2023] Open
Abstract
The use of biodegradable polymers for treating bone-related diseases has become a focal point in the field of biomedicine. Recent advancements in material technology have expanded the range of materials suitable for orthopaedic implants. Three-dimensional (3D) printing technology has become prevalent in healthcare, and while organ printing is still in its early stages and faces ethical and technical hurdles, 3D printing is capable of creating 3D structures that are supportive and controllable. The technique has shown promise in fields such as tissue engineering and regenerative medicine, and new innovations in cell and bio-printing and printing materials have expanded its possibilities. In clinical settings, 3D printing of biodegradable metals is mainly used in orthopedics and stomatology. 3D-printed patient-specific osteotomy instruments, orthopedic implants, and dental implants have been approved by the US FDA for clinical use. Metals are often used to provide support for hard tissue and prevent complications. Currently, 70-80% of clinically used implants are made from niobium, tantalum, nitinol, titanium alloys, cobalt-chromium alloys, and stainless steels. However, there has been increasing interest in biodegradable metals such as magnesium, calcium, zinc, and iron, with numerous recent findings. The advantages of 3D printing, such as low manufacturing costs, complex geometry capabilities, and short fabrication periods, have led to widespread adoption in academia and industry. 3D printing of metals with controllable structures represents a cutting-edge technology for developing metallic implants for biomedical applications. This review explores existing biomaterials used in 3D printing-based orthopedics as well as biodegradable metals and their applications in developing metallic medical implants and devices. The challenges and future directions of this technology are also discussed.
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Grants
- (LGF22H060023 to WQL) Public Technology Applied Research Projects of Zhejiang Province
- (2022KY433 to WQL, 2023KY1303 to HGL) Medical and Health Research Project of Zhejiang Province
- (2022KY433 to WQL, 2023KY1303 to HGL) Medical and Health Research Project of Zhejiang Province
- (2021FSYYZY45 to WQL) Research Fund Projects of The Affiliated Hospital of Zhejiang Chinese Medicine University
- (2022C31034 to CZ, 2023C31019 to HJZ) Science and Technology Project of Zhoushan
- (2022C31034 to CZ, 2023C31019 to HJZ) Science and Technology Project of Zhoushan
- (2022ZB380 to JYZ, 2023016295 to WYM, 2023007231 to CYJ ) Traditional Chinese Medicine Science and Technology Projects of Zhejiang Province
- (2022ZB380 to JYZ, 2023016295 to WYM, 2023007231 to CYJ ) Traditional Chinese Medicine Science and Technology Projects of Zhejiang Province
- (2022ZB380 to JYZ, 2023016295 to WYM, 2023007231 to CYJ ) Traditional Chinese Medicine Science and Technology Projects of Zhejiang Province
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Affiliation(s)
- Wenqing Liang
- Department of Orthopaedics, Zhoushan Hospital of Traditional Chinese Medicine, Zhejiang Chinese Medical University, 355 Xinqiao Road, Dinghai District, Zhoushan, 316000 Zhejiang Province China
| | - Chao Zhou
- Department of Orthopedics, Zhoushan Guanghua Hospital, Zhoushan, 316000 China
| | - Hongwei Zhang
- Department of Orthopaedics, Zhoushan Hospital of Traditional Chinese Medicine, Zhejiang Chinese Medical University, 355 Xinqiao Road, Dinghai District, Zhoushan, 316000 Zhejiang Province China
| | - Juqin Bai
- Department of Orthopaedics, Zhoushan Hospital of Traditional Chinese Medicine, Zhejiang Chinese Medical University, 355 Xinqiao Road, Dinghai District, Zhoushan, 316000 Zhejiang Province China
| | - Bo Jiang
- Rehabilitation Department, Zhoushan Hospital of Traditional Chinese Medicine, Zhejiang Chinese Medical University, Zhoushan, 316000 China
| | - Chanyi Jiang
- Department of Orthopedics, Zhoushan Hospital of Traditional Chinese Medicine, Zhejiang Chinese Medical University, Zhoushan, 316000 Zhejiang Province P.R. China
| | - Wenyi Ming
- Department of Orthopaedics, Zhoushan Hospital of Traditional Chinese Medicine, Zhejiang Chinese Medical University, 355 Xinqiao Road, Dinghai District, Zhoushan, 316000 Zhejiang Province China
| | - Hengjian Zhang
- Department of Orthopaedics, Zhoushan Hospital of Traditional Chinese Medicine, Zhejiang Chinese Medical University, 355 Xinqiao Road, Dinghai District, Zhoushan, 316000 Zhejiang Province China
| | - Hengguo Long
- Department of Orthopaedics, Zhoushan Hospital of Traditional Chinese Medicine, Zhejiang Chinese Medical University, 355 Xinqiao Road, Dinghai District, Zhoushan, 316000 Zhejiang Province China
| | - Xiaogang Huang
- Department of Orthopaedics, Zhoushan Hospital of Traditional Chinese Medicine, Zhejiang Chinese Medical University, 355 Xinqiao Road, Dinghai District, Zhoushan, 316000 Zhejiang Province China
| | - Jiayi Zhao
- Department of Orthopaedics, Zhoushan Hospital of Traditional Chinese Medicine, Zhejiang Chinese Medical University, 355 Xinqiao Road, Dinghai District, Zhoushan, 316000 Zhejiang Province China
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Antohe ME, Dascălu CG, Forna DA, Hitruc EG, Cimpoeșu N, Forna NC. Research on the Quality of Partially Removable Skeletal Prostheses Made Using Classical Versus Modern Sintering Techniques. Biomedicines 2023; 11:2397. [PMID: 37760838 PMCID: PMC10525243 DOI: 10.3390/biomedicines11092397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/22/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023] Open
Abstract
Conventional partially removable skeletal dentures are one of the most common therapeutic solutions offered to edentulous patients worldwide. The present study aims to compare the skeleton of removable dentures realized via classical techniques to that realized via modern techniques, represented by the laser sintering technique, with the comparative aspects being realized through the evaluation of atomic force microscopy (AFM). A total of 20 metal frameworks made of Co-Cr were sectioned, representing the infrastructure of partially removable skeletal dentures, developed using the classical technique versus the laser sintering technique. The infrastructures of partially removable skeletal dentures were designed for both the maxilla and the mandible, with the design of each type of denture being identical, and were developed using both techniques. The roughness values are different depending on the technological method used; for the conventional casting technique, we have higher roughness for the component elements of the partially removable skeletal denture that have more stretch, e.g., the major connector, and for the 3D laser sintering technique, lower roughness is obtained for the component elements that have a lower stretch, e.g., the clasp arms, the minor connector, or the junction between the saddles and the major connector. The clinical implications of the presence of roughness at the level of the active arms or at the level of the connector saddle junction are represented by the risk of fracture, which confers real discomfort to the patient.
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Affiliation(s)
- Magda-Ecaterina Antohe
- 3rd Dental Medicine Department, Faculty of Dental Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (M.-E.A.); (N.C.F.)
| | - Cristina Gena Dascălu
- Department of Medical Informatics, “Grigore T. Popa” University of Medicine and Pharmacy, 16 Universității Street, 700115 Iasi, Romania
| | - Doriana Agop Forna
- 1st Dental Medicine Department, Faculty of Dental Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 16 Universității Street, 700115 Iasi, Romania
| | - Elena Gabriela Hitruc
- “Petru Poni” Institute of Macromolecular Chemistry, Aleea Grigore Ghica-Vodă, 41A, 700487 Iasi, Romania;
| | - Nicanor Cimpoeșu
- Faculty of Materials Science and Engineering, “Gheorghe Asachi” Technical University, Bulevardul Profesor Dimitrie Mangeron 67, 700050 Iasi, Romania;
| | - Norina Consuela Forna
- 3rd Dental Medicine Department, Faculty of Dental Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (M.-E.A.); (N.C.F.)
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Dawod N, Miculescu M, Antoniac IV, Miculescu F, Agop-Forna D. Metal-Ceramic Compatibility in Dental Restorations According to the Metallic Component Manufacturing Procedure. MATERIALS (BASEL, SWITZERLAND) 2023; 16:5556. [PMID: 37629847 PMCID: PMC10456282 DOI: 10.3390/ma16165556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 08/03/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023]
Abstract
In terms of production technology, metal-ceramic systems for dental restorations comply with a concrete algorithm, the efficiency of which is always dependent on the applications for which they are intended. The first stage involves obtaining metal support, followed by firing the ceramic on the surface of the metal to meet the list of functional and aesthetic requirements of a future restoration. The compatibility of the two materials-the metal component and the ceramic component-must be ensured in several respects: chemical compatibility, thermo-chemical compatibility, and mechanical compatibility. Thus, there is a need to simulate the thermal behavior of the metal-ceramic couple in its processing to achieve appropriate dental prostheses. In this study, three types of Co-Cr metal frames were manufactured using three different production technologies: conventional casting, milling (CAM), and selective laser melting (SLM). Composition analyses, scanning electron microscopy (SEM), and microstructural analyses of the metal-ceramic interface for each type of production technology, as well as the determination of the hardness and the thermal expansion coefficients of experimental materials and three-point bending tests, were carried out in this study. Considering all these aspects, we demonstrated the influence of the technology of producing the metallic part of the metal-ceramic bonding process in dental prostheses.
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Affiliation(s)
- Nazem Dawod
- Faculty of Material Science and Engineering, University Politehnica of Bucharest, 313 Splaiul Independentei, District 6, 060042 Bucharest, Romania; (N.D.); (I.V.A.); (F.M.)
- SC Sesene Dent SRL, 37 Vulcan Judetul Street, District 3, 030055 Bucharest, Romania
| | - Marian Miculescu
- Faculty of Material Science and Engineering, University Politehnica of Bucharest, 313 Splaiul Independentei, District 6, 060042 Bucharest, Romania; (N.D.); (I.V.A.); (F.M.)
| | - Iulian Vasile Antoniac
- Faculty of Material Science and Engineering, University Politehnica of Bucharest, 313 Splaiul Independentei, District 6, 060042 Bucharest, Romania; (N.D.); (I.V.A.); (F.M.)
- Academy of Romanian Scientists, 54 Splaiul Independentei, 050094 Bucharest, Romania
| | - Florin Miculescu
- Faculty of Material Science and Engineering, University Politehnica of Bucharest, 313 Splaiul Independentei, District 6, 060042 Bucharest, Romania; (N.D.); (I.V.A.); (F.M.)
| | - Doriana Agop-Forna
- “Gr.T. Popa” University of Medicine and Pharmacy, 16 Universității Street, 700115 Iași, Romania;
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Kassapidou M, Stenport VF, Johansson CB, Syverud M, Hammarström Johansson P, Börjesson J, Hjalmarsson L. Cobalt chromium alloys in fixed prosthodontics: Investigations of mechanical properties and microstructure. J Prosthet Dent 2023; 130:255.e1-255.e10. [PMID: 37355405 DOI: 10.1016/j.prosdent.2023.05.005] [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: 12/17/2022] [Revised: 05/10/2023] [Accepted: 05/11/2023] [Indexed: 06/26/2023]
Abstract
STATEMENT OF PROBLEM Cobalt chromium (Co-Cr) alloys possess beneficial mechanical properties because alloys, even in thin sections, can resist high mastication forces and exhibit an acceptable bond to the surface porcelain layer. Traditional manufacturing techniques of Co-Cr alloys such as casting have been replaced with newer fabrication techniques, such as milling, laser melting, and presintered milling. Despite scarce documentation, these new manufacturing techniques are being used to fabricate dental and implant constructions. PURPOSE This in vitro study investigates the hardness, yield strength, elastic modulus, and microstructure of the most commonly used Co-Cr alloys for fixed prosthodontics based on manufacturing technique. In addition, this study investigates the effect of heat treatment on the mechanical properties and microstructure of these materials. MATERIAL AND METHODS Five Co-Cr alloys were included (dumbbell and rectangular shaped) based on four manufacturing techniques: cast, milled, laser melted, and presintered milled. Commercially pure titanium grade 4 and titanium-6 aluminum-4 vanadium ELI (extra low interstitial) were included for comparison, and yield strength and elongation after fracture were evaluated. The specimens were tested for hardness using the Vickers test and for elastic modulus using a nondestructive impulse excitation technique. The microstructure of selected specimens was analyzed using focused ion beam-scanning electron microscopy (FIB-SEM) and energy dispersive X-ray spectroscopy (EDS). RESULTS The mechanical properties depend on the manufacturing technique used; the laser-melted and presintered Co-Cr specimens demonstrated the highest mechanical properties, followed by the milled and cast groups. Both the laser-melted and the presintered milled Co-Cr specimens showed smaller grain size compared with the cast and milled Co-Cr specimens. The titanium-6 aluminum-4 vanadium ELI demonstrated higher hardness and yield strength compared to commercially pure titanium grade 4. No major differences were observed for the selected materials regarding the mechanical properties and microstructural appearance after heat treatment. CONCLUSIONS The laser melting and presintered milling techniques produced higher mechanical properties compared with the cast and milled Co-Cr. These findings were confirmed through microstructural analysis with respect to the grain size, precipitation, and number of pores.
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Affiliation(s)
- Maria Kassapidou
- Researcher, Department of Prosthodontics/Dental Materials Science, Institute of Odontology, The Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden; Researcher, Department of Prosthetic Dentistry, Institute for Postgraduate Dental Education, Jönköping, Sweden.
| | - Victoria Franke Stenport
- Professor, Department of Prosthodontics/Dental Materials Science, Institute of Odontology, The Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Carina B Johansson
- Professor Emerita, Department of Prosthodontics/Dental Materials Science, Institute of Odontology, The Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Morten Syverud
- Researcher, NIOM, Nordic Institute of Dental Materials, Oslo, Norway
| | - Petra Hammarström Johansson
- Researcher, Department of Prosthodontics/Dental Materials Science, Institute of Odontology, The Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Johan Börjesson
- Researcher, Department of Materials and Manufacturing, School of Engineering, Jönköping University, Jönköping, Sweden
| | - Lars Hjalmarsson
- Lecturer, Department of Prosthodontics/Dental Materials Science, Institute of Odontology, The Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden; Researcher, Centre for Clinical Research Sörmland, Uppsala University, Eskilstuna, Sweden
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Okano H, Tasaka A, Matsunaga S, Kasahara M, Wadachi J, Hattori M, Abe S, Yamashita S. Effects of hollow structures added by selective laser sintering on the mechanical properties of Co-Cr alloy. J Prosthodont Res 2023; 67:460-467. [PMID: 36403960 DOI: 10.2186/jpr.jpr_d_22_00150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/01/2023]
Abstract
PURPOSE This study investigates the effects of hollow structures, added by selective laser sintering (SLS), on the mechanical properties of a Co-Cr alloy for providing an optimal structural property to the framework components of removable partial dentures (RPDs). METHODS The specimens produced using the 3D data of the dumbbell-shaped cylinders were divided into four groups based on the manufacturing method: Cast, Mill, SLS-solid, and SLS-hollow. Tensile tests were performed to measure the mechanical properties of the specimens. The mechanical property values among the four groups were statistically compared using the Kruskal-Wallis test followed by the Steel-Dwass test (α = 0.05). RESULTS The median elastic modulus was the largest in the Cast, followed by SLS-solid, Mill, and SLS-hollow, with no significant differences observed between all conditions. The median ultimate tensile strength was the largest in the order of SLS-solid, Mill, SLS-hollow, and Cast. The median 0.2% proof stress was the largest in SLS-solid, followed by SLS-hollow, Cast, and Mill. The median elongation was the highest in the order of Mill, SLS-solid, SLS-hollow, and Cast. CONCLUSIONS With the addition of hollow structures, the elastic modulus decreased while the mechanical strength and proof stress remained high in SLS specimens. In addition, the ISO 22674 standard for dental metals was met, suggesting that SLS may be a possible method to design RPD frameworks with high strength and optimal structural properties.
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Affiliation(s)
- Haruna Okano
- Department of Removable Partial Prosthodontics, Tokyo Dental College, Tokyo, Japan
| | - Akinori Tasaka
- Department of Removable Partial Prosthodontics, Tokyo Dental College, Tokyo, Japan
| | | | - Masaaki Kasahara
- Department of Dental Materials Science, Tokyo Dental College, Tokyo, Japan
| | - Juro Wadachi
- Department of Removable Partial Prosthodontics, Tokyo Dental College, Tokyo, Japan
| | - Masayuki Hattori
- Department of Dental Materials Science, Tokyo Dental College, Tokyo, Japan
| | - Shinichi Abe
- Department of Anatomy, Tokyo Dental College, Tokyo, Japan
| | - Shuichiro Yamashita
- Department of Removable Partial Prosthodontics, Tokyo Dental College, Tokyo, Japan
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Yun Y, Kang H, Kim EC, Park S, Lee YS, Yun K. Fundamental Properties and Clinical Application of 3D-Printed Bioglass Porcelain Fused to Metal Dental Restoration. Int J Mol Sci 2023; 24:ijms24087203. [PMID: 37108364 PMCID: PMC10138347 DOI: 10.3390/ijms24087203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/29/2023] [Accepted: 04/11/2023] [Indexed: 04/29/2023] Open
Abstract
The purpose of this study is to evaluate the mechanical properties and clinical fitness of 3D-printed bioglass porcelain fused to metal (PFM) dental crowns. To evaluate the mechanical properties, tensile strength, Vickers microhardness, shear bond strength, and surface roughness tests of the SLM printed Co-Cr alloy was conducted. A right mandibular 1st molar tooth was prepared for a single dental crown (n = 10). For a three-unit metal crown and bridge, the right mandibular first premolar and first molar were prepared. Bioglass porcelain was fired to fabricate PFM dental restorations. A clinical gap was observed and measured during each of the four times porcelain was fired. A statistical analysis was conducted. The SLM technique showed the largest statistically significant tensile strength and a 0.2% yield strength value. The milling technique had the lowest statistically significant compressive strength value. The shear bond strength and surface roughness showed no statistically significant difference between the fabricated method. There was a statistically significant change in marginal discrepancy according to the porcelain firing step. The casting technique showed the greatest statistically significant margin discrepancy value. The SLM method showed better fitness than the traditional casting method and showed better mechanical properties as a dental material.
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Affiliation(s)
- Yangan Yun
- Department of Prosthodontics, School of Dentistry, Chonnam National University, 33 Yongbongro, Bukgu, Gwangju 61186, Republic of Korea
| | - Hyeon Kang
- Department of Prosthodontics, School of Dentistry, Chonnam National University, 33 Yongbongro, Bukgu, Gwangju 61186, Republic of Korea
- Ace Dental Clinic, 56, Namak 3-ro, Samhyang-eup, Muan-gun 58567, Republic of Korea
| | - Eun-Chae Kim
- Department of Dental Laboratory Technology, Gwangju Health University, 73, Bungmun-daero 419beon-gil, Gwangsan-gu, Gwangju 62287, Republic of Korea
| | - Sangwon Park
- Department of Prosthodontics, School of Dentistry, Chonnam National University, 33 Yongbongro, Bukgu, Gwangju 61186, Republic of Korea
| | - Yong-Seok Lee
- Department of Mechanical Engineering, Myeongji University, Yongin 17058, Republic of Korea
| | - Kwidug Yun
- Department of Prosthodontics, School of Dentistry, Chonnam National University, 33 Yongbongro, Bukgu, Gwangju 61186, Republic of Korea
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Souza Curinga MR, Claudino Ribeiro AK, de Moraes SLD, do Egito Vasconcelos BC, da Fonte Porto Carreiro A, Pellizzer EP. Mechanical properties and accuracy of removable partial denture frameworks fabricated by digital and conventional techniques: A systematic review. J Prosthet Dent 2023:S0022-3913(23)00075-6. [PMID: 36870892 DOI: 10.1016/j.prosdent.2023.01.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 03/06/2023]
Abstract
STATEMENT OF PROBLEM Providing a removable partial denture (RPD) can be a complex, time-consuming, and error-prone procedure. Computer-aided design and computer-aided manufacturing (CAD-CAM) techniques have shown promising clinical outcomes; however, the influence of manufacturing techniques on the properties of RPD components is unclear. PURPOSE The purpose of this systematic review was to determine the accuracy and mechanical properties of RPD components fabricated with conventional and digital methods. MATERIAL AND METHODS This study followed the guidelines of the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) and was registered on the international prospective register of systematic reviews (PROSPERO) database (CRD42022353993). An electronic search was conducted on PubMed/MEDLINE, Scopus, Web of Science, and the Cochrane Library in August 2022. Only in vitro studies comparing the digital with the lost-wax casting technique were included. The quality of the studies was assessed by using the methodological index for nonrandomized studies (MINORS) scale. RESULTS Of the 17 selected studies, 5 evaluated the accuracy of RPD components as well as the mechanical properties, 5 studies evaluated only the component accuracy, and another 7 evaluated only the mechanical properties. The accuracy was similar regardless of the technique, with discrepancies within clinically acceptable values (50 to 426.3 μm). The surface roughness was higher for 3D-printed clasps and lower for milled clasps (P<.05). The metal alloy significantly influenced the porosity, with the highest number of pores obtained by casting for Ti clasps and by rapid prototyping for Co-Cr clasps. CONCLUSIONS In vitro studies showed that the digital technique provided similar accuracy to that of the conventional technique within a clinically acceptable range. The manufacturing technique influenced the mechanical properties of RPD components.
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Affiliation(s)
| | | | - Sandra Lúcia Dantas de Moraes
- Associate Professor, Division of Oral Rehabilitation, Faculty of Dentistry, University of Pernambuco (UPE), Recife, PE, Brazil
| | | | | | - Eduardo Piza Pellizzer
- Full Professor, Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), Araçatuba, SP, Brazil
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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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Herrero-Climent M, Punset M, Molmeneu M, Brizuela A, Gil J. Differences between the Fittings of Dental Prostheses Produced by CAD-CAM and Laser Sintering Processes. J Funct Biomater 2023; 14:jfb14020067. [PMID: 36826866 PMCID: PMC9959825 DOI: 10.3390/jfb14020067] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 01/20/2023] [Accepted: 01/21/2023] [Indexed: 01/30/2023] Open
Abstract
Digital dentistry and new techniques for the dental protheses' suprastructure fabrication have undergone a great evolution in recent years, revolutionizing the quality of dental prostheses. The aim of this work is to determine whether the best horizontal marginal fit is provided by the CAD-CAM technique or by laser sintering. These values have been compared with the traditional casting technique. A total of 30 CAD-CAM models, 30 laser sintering models, and 10 casting models (as control) were fabricated. The structures realized with chromium-cobalt (CrCo) have been made by six different companies, always with the same model. Scanning electron microscopy with a high-precision image analysis system was used, and 10,000 measurements were taken for each model on the gingival (external) and palatal (internal) side. Thus, a total of 1,400,000 images were measured. It was determined that the CAD-CAM technique is the one that allows the best adjustments in the manufacturing methods studied. The laser sintering technique presents less adjustment, showing the presence of porosities and volume contraction defects due to solidification processes and heterogeneities in the chemical composition (coring). The technique with the worst adjustments is the casting technique, containing numerous defects in the suprastructure. The statistical analysis of results reflected the presence of statistically significant gap differences between the three manufacturing methods analyzed (p < 0.05), with the samples manufactured by CAD-CAM and by traditional casting processes being the ones that showed lower and higher values, respectively. No statistically significant differences in fit were observed between the palatal and gingival fit values, regardless of the manufacturing method used. No statistically significant differences in adjustment between the different manufacturing centers were found, regardless of the process used.
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Affiliation(s)
| | - Miquel Punset
- Biomaterials, Biomechanics and Tissue Engineering Group (BBT), Department of Materials Science and Engineering, Universitat Politècnica de Catalunya (UPC), Av. Edurad Maristany 16, 08019 Barcelona, Spain
- Barcelona Research Centre in Multiscale Science and Engineering, Technical University of Catalonia (UPC), Av. Eduard Maristany, 10-14, 08019 Barcelona, Spain
| | - Meritxell Molmeneu
- Biomaterials, Biomechanics and Tissue Engineering Group (BBT), Department of Materials Science and Engineering, Universitat Politècnica de Catalunya (UPC), Av. Edurad Maristany 16, 08019 Barcelona, Spain
- Barcelona Research Centre in Multiscale Science and Engineering, Technical University of Catalonia (UPC), Av. Eduard Maristany, 10-14, 08019 Barcelona, Spain
| | - Aritza Brizuela
- Facultad de Odontología, Universidad Europea Miguel de Cervantes, C/del Padre Julio Chevalier 2., 47012 Valladolid, Spain
| | - Javier Gil
- Bioengineering Institute of Technology, Faculty of Medicine and Health Sciences, International University of Catalonia, Josep Trueta s/n, 08195 Barcelona, Spain
- Correspondence:
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Poly (Ether-Ether-Ketone) for Biomedical Applications: From Enhancing Bioactivity to Reinforced-Bioactive Composites-An Overview. Polymers (Basel) 2023; 15:polym15020373. [PMID: 36679253 PMCID: PMC9861117 DOI: 10.3390/polym15020373] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 12/21/2022] [Accepted: 12/24/2022] [Indexed: 01/13/2023] Open
Abstract
The global orthopedic market is forecasted to reach US$79.5 billion by the end of this decade. Factors driving the increase in this market are population aging, sports injury, road traffic accidents, and overweight, which justify a growing demand for orthopedic implants. Therefore, it is of utmost importance to develop bone implants with superior mechanical and biological properties to face the demand and improve patients' quality of life. Today, metallic implants still hold a dominant position in the global orthopedic implant market, mainly due to their superior mechanical resistance. However, their performance might be jeopardized due to the possible release of metallic debris, leading to cytotoxic effects and inflammatory responses in the body. Poly (ether-ether-ketone) (PEEK) is a biocompatible, high-performance polymer and one of the most prominent candidates to be used in manufacturing bone implants due to its similarity to the mechanical properties of bone. Unfortunately, the bioinert nature of PEEK culminates in its diminished osseointegration. Notwithstanding, PEEK's bioactivity can be improved through surface modification techniques and by the development of bioactive composites. This paper overviews the advantages of using PEEK for manufacturing implants and addresses the most common strategies to improve the bioactivity of PEEK in order to promote enhanced biomechanical performance.
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Comparative assessment of marginal and internal gaps of cast-free monolithic zirconia crowns fabricated from 2 intraoral scanners: A prospective, double-blind, randomized clinical trial. J Prosthet Dent 2023; 129:69-75. [PMID: 35985854 DOI: 10.1016/j.prosdent.2022.05.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 01/18/2023]
Abstract
STATEMENT OF PROBLEM Despite the introduction of intraoral scanners (IOSs) with dual camera triangulation, only a few comparative clinical studies have evaluated their clinical performances in the digital workflow for cast-free restorations. PURPOSE The purpose of this clinical trial was to assess the clinical efficacy of 2 different technology-based IOSs by evaluating the marginal and internal gaps of cast-free monolithic zirconia crowns fabricated by using a fully digital workflow. MATERIAL AND METHODS A prospective randomized clinical trial was conducted in 35 participants requiring a single-unit restoration. One crown was fabricated from the scan data obtained with a confocal microscopy-based IOS (Group T), while the other was made with the scan data obtained from an IOS using dual camera triangulation (Group I). A replica technique was used to assess the marginal and internal gaps. The buccolingual and mesiodistal cross-sections were measured, and noninferiority trials were performed. RESULTS A total of 39 teeth from 35 participants were restored with a single-unit crown. The marginal and axial wall gaps of the crowns in Group I was not inferior to that of the crowns in Group T (upper limit confidence interval [CI] <30). In contrast, the gap of the crowns at the line angle in Group T was inferior to that of the crowns in Group I (lower limit CI <-30). From an occlusal space perspective, the gap of the crowns in Group I was inferior to that of the crowns in Group T (upper limit CI >30). Twenty-five crowns were selected from Group I, and 14 crowns were selected from Group T for definitive placement. CONCLUSIONS The marginal gap of the crown fabricated by using the scan data obtained from the dual camera triangulation-based IOS was noninferior to that obtained from the confocal microscopy-based IOS and was within the clinically applicable limit.
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Bonfante EA, Calamita M, Bergamo ETP. Indirect restorative systems-A narrative review. J ESTHET RESTOR DENT 2023; 35:84-104. [PMID: 36688803 DOI: 10.1111/jerd.13016] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/03/2023] [Accepted: 01/04/2023] [Indexed: 01/24/2023]
Abstract
OBJECTIVE The background and clinical understanding of the properties of currently available indirect restorative systems and fabrication methods is, along with manufacturer and evidence-based literature, an important starting point to guide the clinical selection of materials for tooth and/or implant supported reconstructions. Therefore, this review explores most indirect restorative systems available in the market, especially all-ceramic, along with aspects of manufacturing process, clinical survival rates, and esthetic outcomes. OVERVIEW Progressive incorporation of new technologies in the dental field and advancements in materials science have enabled the development/improvement of indirect restorative systems and treatment concepts in oral rehabilitation, resulting in reliable and predictable workflows and successful esthetic and functional outcomes. Indirect restorative systems have evolved from metal ceramics and polymers to glass ceramics, polycrystalline ceramics, and resin-matrix ceramics, aiming to improve not only biological and mechanical properties, but especially the optical properties and esthetic quality of the reconstructions, in attempt to mimic natural teeth. CONCLUSIONS Based on several clinical research, materials, and patient-related parameters, a decision tree for the selection of indirect restorative materials was suggested to guide clinicians in the rehabilitation process. CLINICAL SIGNIFICANCE The pace of materials development is faster than that of clinical research aimed to support their use. Since no single material provides an ideal solution to every case, professionals must continuously seek information from well designed, long-term clinical trials in order to incorporate or not new materials and technological advancements.
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Affiliation(s)
- Estevam A Bonfante
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry - University of São Paulo, Bauru, SP, Brazil
| | - Marcelo Calamita
- Department of Restorative Dental Sciences at the University of Florida, Gainesville, Florida, USA
| | - Edmara T P Bergamo
- Department of Prosthodontics and Periodontology, Bauru School of Dentistry - University of São Paulo, Bauru, SP, Brazil
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Saha S, Roy S. Metallic Dental Implants Wear Mechanisms, Materials, and Manufacturing Processes: A Literature Review. MATERIALS (BASEL, SWITZERLAND) 2022; 16:ma16010161. [PMID: 36614500 PMCID: PMC9821388 DOI: 10.3390/ma16010161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 11/29/2022] [Accepted: 12/13/2022] [Indexed: 06/12/2023]
Abstract
OBJECTIVES From the treatment of damaged teeth to replacing missing teeth, dental biomaterials cover the scientific interest of many fields. Dental biomaterials are one of the implants whose effective life depends vastly on their material and manufacturing techniques. The purpose of this review is to summarize the important aspects for metallic dental implants from biomedical, mechanical and materials science perspectives. The review article will focus on five major aspects as mentioned below. Tooth anatomy: Maximizing the implant performance depends on proper understanding of human tooth anatomy and the failure behavior of the implants. Major parts from tooth anatomy including saliva characteristics are explored in this section. Wear mechanisms: The prominent wear mechanisms having a high impact on dental wear are abrasive, adhesive, fatigue and corrosion wear. To imitate the physiological working condition of dental implants, reports on the broad range of mastication force and various composition of artificial saliva have been included in this section, which can affect the tribo-corrosion behavior of dental implants. Dental implants classifications: The review paper includes a dedicated discussion on major dental implants types and their details for better understanding their applicability and characteristics. Implant materials: As of today, the most established dental implant materials are SS316L, cobalt chrome alloy and titanium. Detailed discussion on their material properties, microstructures, phase transformations and chemical compositions have been discussed here. Manufacturing techniques: In terms of different production methods, the lost wax casting method as traditional manufacturing is considered. Selective Laser Melting (SLM) and Directed Energy Deposition (DED) as additive manufacturing techniques (AM) have been discussed. For AM, the relationships between process-property-performance details have been explored briefly. The effectiveness of different manufacturing techniques was compared based on porosity distribution, mechanical and biomechanical properties. SUMMARY Despite having substantial research available on dental implants, there is a lack of systematic reviews to present a holistic viewpoint combining state-of-the-art from biomedical, mechanical, materials science and manufacturing perspectives. This review article attempts to combine a wide variety of analyzing approaches from those interdisciplinary fields to deliver deeper insights to researchers both in academia and industry to develop next-generation dental implants.
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Findrik Balogová A, Rajťúková V, Chromý Ľ, Somoš A, Ižaríková G, Hudák R. Biomechanical Testing of Two-Unit Bridges and a Comparison of Replacement Retention Depending on a Cementation Medium, Replacement Position, and Gap Size. J Funct Biomater 2022; 13:jfb13040286. [PMID: 36547547 PMCID: PMC9788551 DOI: 10.3390/jfb13040286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/21/2022] [Accepted: 12/04/2022] [Indexed: 12/13/2022] Open
Abstract
Dental replacements are placed between the abutment teeth. The exceptions are two-unit bridges, as they are supported by a single tooth prepared only on one side of the missing tooth. The presented study deals with an analysis of a pressure force action on two-unit bridges placed in the frontal part (20 samples), where the pressure action is lower, and in the distal part (20 samples), where the pressure action is higher. A CAD program by 3Shape was used for digital designing with two different gap settings, 10 μm (20 samples) and 30 μm (20 samples). Two-unit bridges were attached to the prepared tooth using two types of dental cement (20/20 samples), which were selected for their physical and bioactive properties. All two-unit bridges (a total of 80 samples) were fabricated from CoCr alloys on Mlab cusing R by applying the Selective Laser Melting (SLM) technology. Mechanical testing was performed using the Inspekt5 table blue. The obtained data were used to verify the hypotheses-a difference between both types of cement (A ≠ B), a difference between the frontal and distal two-unit bridges (F ≠ D) and a difference between the gap sizes (10 ≠ 30). To confirm the given theories, data were statistically evaluated using the F-test and subsequent t-tests. The resulting p-value was compared with the level of significance (α = 0.05). A statistical evaluation revealed a significant difference between the compared groups; however, no explicit correlation between the individual groups of specimens was identified.
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Affiliation(s)
- Alena Findrik Balogová
- Department of Biomedical Engineering and Measurement, Faculty of Mechanical Engineering, Technical University of Košice, 040 01 Košice, Slovakia
| | - Viktória Rajťúková
- Department of Biomedical Engineering and Measurement, Faculty of Mechanical Engineering, Technical University of Košice, 040 01 Košice, Slovakia
- Correspondence:
| | - Ľuboš Chromý
- Department of Biomedical Engineering and Measurement, Faculty of Mechanical Engineering, Technical University of Košice, 040 01 Košice, Slovakia
| | - Andrej Somoš
- Clinic of Pneumology and Phthisiology, L. Pasteur University Hospital Košice, 040 11 Košice, Slovakia
| | - Gabriela Ižaríková
- Department of Applied Mathematics and Informatics, Faculty of Mechanical Engineering, Technical University of Košice, 040 01 Košice, Slovakia
| | - Radovan Hudák
- Department of Biomedical Engineering and Measurement, Faculty of Mechanical Engineering, Technical University of Košice, 040 01 Košice, Slovakia
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Daou EE, Özcan M. Evaluation of ceramic adherence to cobalt-chromium alloys fabricated by different manufacturing techniques. J Prosthet Dent 2022; 128:1364.e1-1364.e8. [DOI: 10.1016/j.prosdent.2022.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 10/17/2022] [Accepted: 10/17/2022] [Indexed: 12/15/2022]
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Abstract
Although the accuracy of direct digitization of oral structure has been improved, indirect digitization is still required in specific situations such as full-arch scanning. Once accurate images are imported, efficient designing can be achieved by CAD software. Although smile design using a 3-dimensional facial scan better predicts planned restorations, further improvement in virtual articulators is needed for complex cases. Computer-aided manufacturing can be offered in several formats such as chairside, laboratory, or centralized fabrications. The subtractive technique is mainly used for restorations, and many chairside CAM materials are available now, but the additive technique has the potential to save materials and an advantage in fabricating complex geometries. Limited evidence is available in applying CAD/CAM technologies in implant restorations. However, it is used to fabricate custom implant abutments and crowns from various materials such as titanium, zirconia, and PEEK and hybrid crowns using stock titanium base abutments.
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Affiliation(s)
- Hidehiko Watanabe
- Restorative Dentistry, Oregon Health & Science University, School of Dentistry, 2730 S Moody Avenue, Portland, OR 97201-5042, USA.
| | - Christopher Fellows
- Restorative Dentistry, Oregon Health & Science University, School of Dentistry, 2730 S Moody Avenue, Portland, OR 97201-5042, USA
| | - Hongseok An
- Restorative Dentistry, Oregon Health & Science University, School of Dentistry, 2730 S Moody Avenue, Portland, OR 97201-5042, USA
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Zinelis S, Polychronis G, Papadopoulos F, Kokkinos C, Economou A, Panayi N, Papageorgiou SN, Eliades T. Mechanical and electrochemical characterization of 3D printed orthodontic metallic appliances after in vivo ageing. Dent Mater 2022; 38:1721-1727. [PMID: 36123188 DOI: 10.1016/j.dental.2022.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 09/07/2022] [Accepted: 09/08/2022] [Indexed: 11/03/2022]
Abstract
OBJECTIVES Three-dimensional (3D) printing technology is a promising technique for fabricating custom orthodontic metallic appliances. Aim of this study was to assess the effect of intraoral aging on the mechanical / electrochemical properties of 3D-printed orthodontic metallic appliances. METHODS Twelve molar orthodontic distalization appliances 3D-printed from cobalt chromium (Co-Cr) alloy were retrieved after intraoral use and twenty blocks fabricated under similar conditions were used as control. The samples' microstructural / elemental composition assessment was assessed with SEM/EDS, while their mechanical properties (modulus of elasticity [EIT], Martens hardness [HM] and the elastic index [ηIT]) were measured by instrumented indentation testing. Finally, the samples' electrochemical features were assessed with a potentiostat-connected cell arrangement in terms of open circuit potential (OCP), corrosion potential (Ez), current density (I300) and breaking potential (Epit). Results were analyzed by t-test / Mann-Whitney test (α = 0.05). RESULTS The used Co-Cr alloy was found to have a highly homogenous structure with no significant differences between retrieved and new specimens in HM (4037.7 ± 215.6 vs 4090.9 ± 259.8 N/mm2), EIT (120.0 ± 13.2 vs 123.8 ± 12.9 GPa), or nIT (28.4 ± 2.6 vs 28.6 ± 2.9 %) (P > 0.05 in all instances). Metallic surfaces retained the same oxidation tendency and oxide dissolution rate in passive region in both groups (P > 0.05 for OCP, Ez, and I300). However, intraorally-aged specimens had a significantly lower breakdown potential due to degraded protection efficacy of surface oxide (P = 0.003 for Epit). SIGNIFICANCE The tested 3D-printed Co-Cr orthodontic appliances present clinically-acceptable mechanical properties that remained unaffected by intraoral ageing, which however degraded the protection of surface oxide against pitting corrosion.
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Affiliation(s)
- Spiros Zinelis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgios Polychronis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Frixos Papadopoulos
- Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Christos Kokkinos
- Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Anastasios Economou
- Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Athens, Greece
| | - Nearchos Panayi
- Department of Dentistry, European University Cyprus, Nicosia, Cyprus; Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Spyridon N Papageorgiou
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland
| | - Theodore Eliades
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
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Abd-Elaziem W, Elkatatny S, Abd-Elaziem AE, Khedr M, Abd El-baky MA, Hassan MA, Abu-Okail M, Mohammed M, Järvenpää A, Allam T, Hamada A. On the current research progress of metallic materials fabricated by laser powder bed fusion process: a review. JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY 2022; 20:681-707. [DOI: 10.1016/j.jmrt.2022.07.085] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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Băilă DI, Păcurar R, Savu T, Zaharia C, Trușcă R, Nemeș O, Górski F, Păcurar A, Pleșa A, Sabău E. Mechanical and Wetting Properties of Ta 2O 5 and ZnO Coatings on Alloy Substrate of Cardiovascular Stents Manufactured by Casting and DMLS. MATERIALS (BASEL, SWITZERLAND) 2022; 15:5580. [PMID: 36013717 PMCID: PMC9412485 DOI: 10.3390/ma15165580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 06/15/2023]
Abstract
In the last years, additive manufacturing technologies have been developed, especially direct metal laser sintering, and used in the dental and medical implant domains. Cardiovascular stents have evolved from bioinert, bare metal cages to biomimetic devices that promote tissue regeneration or healing. In this paper, comparisons concerning mechanical properties between Co-Cr alloy and cast 304L stainless steel were realized using FEM analysis, necessary for manufacturing cardiovascular stents by DMLS technology using Co-Cr alloy. The purpose of this paper consists of the evaluation of the contact angle at the interface of the Co-Cr alloy manufactured by DMLS, respectively, cast stainless steel 304L, and thin film deposition realized by the e-gun method (Ta2O5 and ZnO). Scanning electronic microscopy SEM and EDX techniques were employed for morphological investigation of the sintered samples manufactured by the DMLS process. They were also used for semi-quantitative and qualitative chemical and metallographic analyses. The e-gun coating was used to obtain thin films with the nanometer order of Ta2O5 and ZnO with a protective role to improve the corrosion resistance, roughness, and antiseptic role.
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Affiliation(s)
- Diana-Irinel Băilă
- Department of Manufacturing Engineering, Faculty of Industrial Engineering and Robotics, University Politehnica of Bucharest, Blv. Splaiul Independenței, No. 313, Sector 6, 060042 Bucharest, Romania
| | - Răzvan Păcurar
- Department of Manufacturing Engineering, Faculty of Industrial Engineering, Robotics and Production Management, Technical University of Cluj-Napoca, Blv. Muncii, No. 103-105, 400641 Cluj-Napoca, Romania
| | - Tom Savu
- Department of Manufacturing Engineering, Faculty of Industrial Engineering and Robotics, University Politehnica of Bucharest, Blv. Splaiul Independenței, No. 313, Sector 6, 060042 Bucharest, Romania
| | - Cătălin Zaharia
- Advanced Polymer Materials Group, Department of Bioresources and Polymer Science, University Politehnica of Bucharest, 1-7 Gh. Polizu Street, 011061 Bucharest, Romania
| | - Roxana Trușcă
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, Blv. Splaiul Independenței, No. 313, Sector 6, 060042 Bucharest, Romania
| | - Ovidiu Nemeș
- Department of Environmental Engineering and Sustainable Development Entrepreneurship, Faculty of Materials and Environmental Engineering, Technical University of Cluj-Napoca, Blv. Muncii, No. 103-105, 400641 Cluj-Napoca, Romania
| | - Filip Górski
- Faculty of Mechanical Engineering, Poznan University of Technology, 60-965 Poznan, Poland
| | - Ancuța Păcurar
- Department of Manufacturing Engineering, Faculty of Industrial Engineering, Robotics and Production Management, Technical University of Cluj-Napoca, Blv. Muncii, No. 103-105, 400641 Cluj-Napoca, Romania
| | - Alin Pleșa
- Department of Mechatronics and Machine Dynamics, Faculty of Automotive, Mechatronics and Mechanical Engineering, Technical University of Cluj-Napoca, Blv. Muncii, No. 103-105, 400641 Cluj-Napoca, Romania
| | - Emilia Sabău
- Department of Manufacturing Engineering, Faculty of Industrial Engineering, Robotics and Production Management, Technical University of Cluj-Napoca, Blv. Muncii, No. 103-105, 400641 Cluj-Napoca, Romania
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Salim S, Salleh NM, Abidin ZZ, Yunus N, Rahmat R, Ibrahim N. Physicomechanical properties of cobalt-chromium removable partial denture palatal major connectors fabricated by selective laser melting. J Prosthet Dent 2022; 128:530.e1-530.e7. [PMID: 35933173 DOI: 10.1016/j.prosdent.2022.06.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 06/25/2022] [Accepted: 06/28/2022] [Indexed: 10/16/2022]
Abstract
STATEMENT OF PROBLEM Additive manufacturing by selective laser melting (SLM) has been claimed to be less challenging than conventional casting of cobalt-chromium (Co-Cr) removable partial dentures (RPDs), providing significant improvements. However, how the physicomechanical properties of Co-Cr RPDs fabricated by SLM compare with those fabricated by conventional casting is unclear. PURPOSE The purpose of this in vitro study was to evaluate the physicomechanical properties of Co-Cr RPD palatal major connectors fabricated by SLM compared with those fabricated by conventional casting. MATERIAL AND METHODS A master die simulating a maxillary arch of Kennedy class III modification 1 was scanned to create a virtual 3-dimensional (3D) cast. Two groups of 5 Co-Cr RPD major connectors were fabricated. In the 3D printing group, the Co-Cr major connector was virtually designed and exported for direct SLM 3D printing. For the conventional group, Co-Cr major connectors were constructed conventionally. The Co-Cr major connectors were virtually superimposed with the master die for surface adaptation analysis. Additional comparative analyses of surface roughness, relative density, microhardness, and microstructure of the 2 groups were performed. Data were analyzed by using independent t tests (α=.05). RESULTS The overall volumetric and linear discrepancies were significantly higher (P<.05) in the 3D printing group. Significant differences in the surface roughness (P<.05) and microhardness (P<.05) were observed, with the 3D printing group having higher surface roughness and microhardness than the conventional group. Unlike conventional connectors, the microstructure of 3D-printed connectors showed fine homogeneous granules. CONCLUSIONS Compared with the conventional casting technique, SLM 3D printing enabled the fabrication of Co-Cr RPD major connectors with higher microhardness and fine homogenous microstructure. However, the surface adaptation and surface roughness of SLM 3D printing Co-Cr connectors were worse than those produced conventionally. Both techniques showed similar relative densities.
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Affiliation(s)
- Safa Salim
- PhD student, Department of Restorative Dentistry, Faculty of Dentistry, University Malaya, Kuala Lumpur, Malaysia
| | - Nosizana Mohd Salleh
- Associated Professor, Department of Restorative Dentistry, Faculty of Dentistry, University Malaya, Kuala Lumpur, Malaysia
| | - Zubaidah Zanul Abidin
- Lecturer, Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - Norsiah Yunus
- Professor, Department of Restorative Dentistry, Faculty of Dentistry, University Malaya, Kuala Lumpur, Malaysia
| | - Rabiah Rahmat
- Lecturer, Department of Oral and Maxillofacial Clinical Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - Norliza Ibrahim
- Associated Professor, Department of Oral and Maxillofacial Clinical Sciences, Faculty of Dentistry, University Malaya, Kuala Lumpur, Malaysia.
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Comparison of four CAD-CAM guides for preparing guiding planes of removable partial dentures. Comput Biol Med 2022; 146:105564. [DOI: 10.1016/j.compbiomed.2022.105564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/21/2022] [Accepted: 04/25/2022] [Indexed: 11/18/2022]
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Electrochemical characterization of three types of Co-Cr based alloys manufactured by casting and selective laser melting according to ISO 10271. Dent Mater 2022; 38:1162-1172. [PMID: 35690483 DOI: 10.1016/j.dental.2022.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/31/2022] [Accepted: 06/01/2022] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To characterize the effect of elemental composition and manufacturing process on the electrochemical properties of Co-Cr-Mo, Co-Cr-W and Co-Cr-Mo-W alloys. METHODS Six Co-Cr based alloys were included in this study. All alloys are Co-Cr based alloys, classified in three different types according to their elemental composition. The first group has Mo as the third alloying element while the second one has W instead of Mo. The third one has both alloying elements. The groups are further divided by the manufacturing process (casting or Selective Laser Melting(SLM)). All groups were subjected to static immersion, open circuit potential, anodic scan, SEM/EDX analysis, static and cyclic tarnish testing according to ISO 10271 requirements. The ionic release was evaluated by inductively coupled plasma mass spectrometry and the results were statistically analyzed by two way ANOVA and Tukey test (a=0.05). RESULTS No statistical differences were identified for Co-Cr-Mo alloy for all elements and their total ionic release between casting and SLM manufacturing processes, in contrast to significantly lower values for SLM groups for the other two groups. All groups tested demonstrated similar performance in OCP and AS testing while no gross elemental changes before and after AS were identified following EDX analysis. All alloys fulfilled the requirements of tarnish resistance CONCLUSIONS: The ionic release is dependent on alloy type and manufacturing process while all groups were found to fulfill the requirements of international standards for ionic release, corrosion and tarnish resistance and thus an acceptable clinical performance is anticipated.
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Hamed HAE, Hebeshi AM, Husseiny E. Effect of Palatal Vault Depth on the Trueness of Metal Laser-Sintered and Cast Cobalt-Chromium Removable Partial Denture Frameworks. J Prosthodont 2022; 32:353-360. [PMID: 35751546 DOI: 10.1111/jopr.13558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 06/07/2022] [Indexed: 11/30/2022] Open
Abstract
PURPOSE This in vitro study compares the trueness of removable partial denture cobalt-chromium (Co-Cr) frameworks fabricated by 3D-printed pattern casting and those fabricated by selective laser sintering (SLS) of different palate vault depths. MATERIALS AND METHODS A partially edentulous Kennedy class II mod.1 maxillary model with a deep palatal vault was used, which was modified and duplicated to produce another model with medium palatal vault depth. After model scanning, the partial denture framework was designed using CAD software to fabricate 20 removable partial denture (RPD) frameworks. For each model, two types of frameworks were fabricated. For the 1st type, the 3D-printed resin patterns were formed using a 3D printer, and then casting was performed (AM-cast framework). For the 2nd type, a direct metal laser sintering machine was used for the RPD frameworks fabrication (SLS framework). 3D scanning of fabricated frameworks was performed, and the standard tessellation language (STL) file was superimposed over the STL file from the original design, and the average deviation was recorded. Data were statistically analyzed. RESULTS Two-way ANOVA test was used, followed by the least significant difference (LSD) for pair-wise comparisons to estimate any significant differences between groups. The RPD frameworks with high palatal vault depth represent larger discrepancies mean value than that with the medium palatal vault depth with a highly significant statistical difference. SLS shows less deviation than AM-cast CO-Cr frameworks with highly significant statistical differences whatever palatal vault depth. CONCLUSION RPD metal frameworks fabricated with SLS have better accuracy compared to those fabricated by AM-cast, regardless of the depth of the palatal vault. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Hala Abd El Hamed
- Department of Removable Prosthodontics, Faculty of Dentistry, Suez Canal University, Egypt
| | - Ahmed M Hebeshi
- Department of oral and maxillofacial prosthodontics, Faculty of Dentistry, Ain Shams University, Egypt
| | - Eman Husseiny
- Department of Removable Prosthodontics, Faculty of oral and dental medicine, Zagazig University, Egypt
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Fu W, Liu S, Jiao J, Xie Z, Huang X, Lu Y, Liu H, Hu S, Zuo E, Kou N, Ma G. Wear Resistance and Biocompatibility of Co-Cr Dental Alloys Fabricated with CAST and SLM Techniques. MATERIALS 2022; 15:ma15093263. [PMID: 35591597 PMCID: PMC9104588 DOI: 10.3390/ma15093263] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 04/21/2022] [Accepted: 04/28/2022] [Indexed: 12/15/2022]
Abstract
Cobalt–chromium (Co-Cr) alloys have been widely used as dental-restoration materials for many years. This study sought to investigate whether selective laser melting (SLM) is a more appropriate process than traditional casting (CAST) for fabricating dental Co-Cr alloys. Metallurgical microscopy, X-ray photoelectron spectroscopy (XPS), Vickers hardness and nanoindentation tests, and friction and wear tests were used to evaluate the microstructure, surface compositions, mechanical properties, and wear resistance, respectively. Additionally, the biocompatibilities and cell adhesion of the alloys were evaluated with L-929 fibroblasts via CCK-8 assay, Live/Dead staining, flow cytometric analysis, scanning electron microscopy (SEM) observation and real-time PCR (RT-PCR) assay. The XPS results showed that the two alloys were all mainly comprised of Co, Cr, and O. The hardness in the CAST group equaled 7.15 ± 0.48 GPa, while in the SLM group, it equaled 9.06 ± 0.49 GPa. The friction coefficient of SLM alloys remained at approximately 0.46, but the CAST specimens fluctuated significantly. SLM alloys exhibited shallower wear scars and less wear debris compared with CAST alloys, simultaneously. Additionally, there were higher survival and expression of cell-adhesion-related genes on SLM alloys of L-929 cells, which meant that the deleterious effect on L-929 cells was significantly reduced compared with that for the CAST alloys. Overall, the wear resistances and biocompatibilities of the Co-Cr dental alloys were dramatically affected by the fabrication technique. The SLM technique is advantageous over the CAST technique for fabricating Co-Cr dental alloys.
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Affiliation(s)
- Wenqi Fu
- Department of Oral Prosthodontics, School of Stomatology, Dalian Medical University, Lvshun South Road, Dalian 116044, China; (W.F.); (S.L.); (J.J.); (Y.L.); (H.L.); (S.H.); (E.Z.)
- Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Lvshun South Road, Dalian 116044, China
| | - Shuang Liu
- Department of Oral Prosthodontics, School of Stomatology, Dalian Medical University, Lvshun South Road, Dalian 116044, China; (W.F.); (S.L.); (J.J.); (Y.L.); (H.L.); (S.H.); (E.Z.)
- Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Lvshun South Road, Dalian 116044, China
| | - Jun Jiao
- Department of Oral Prosthodontics, School of Stomatology, Dalian Medical University, Lvshun South Road, Dalian 116044, China; (W.F.); (S.L.); (J.J.); (Y.L.); (H.L.); (S.H.); (E.Z.)
- Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Lvshun South Road, Dalian 116044, China
| | - Zhiwen Xie
- School of Mechanical Engineering and Automation, University of Science and Technology Liaoning, Anshan 114051, China; (Z.X.); (X.H.)
| | - Xinfang Huang
- School of Mechanical Engineering and Automation, University of Science and Technology Liaoning, Anshan 114051, China; (Z.X.); (X.H.)
| | - Yun Lu
- Department of Oral Prosthodontics, School of Stomatology, Dalian Medical University, Lvshun South Road, Dalian 116044, China; (W.F.); (S.L.); (J.J.); (Y.L.); (H.L.); (S.H.); (E.Z.)
- Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Lvshun South Road, Dalian 116044, China
| | - Huiying Liu
- Department of Oral Prosthodontics, School of Stomatology, Dalian Medical University, Lvshun South Road, Dalian 116044, China; (W.F.); (S.L.); (J.J.); (Y.L.); (H.L.); (S.H.); (E.Z.)
- Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Lvshun South Road, Dalian 116044, China
| | - Shuhai Hu
- Department of Oral Prosthodontics, School of Stomatology, Dalian Medical University, Lvshun South Road, Dalian 116044, China; (W.F.); (S.L.); (J.J.); (Y.L.); (H.L.); (S.H.); (E.Z.)
- Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Lvshun South Road, Dalian 116044, China
| | - Enjun Zuo
- Department of Oral Prosthodontics, School of Stomatology, Dalian Medical University, Lvshun South Road, Dalian 116044, China; (W.F.); (S.L.); (J.J.); (Y.L.); (H.L.); (S.H.); (E.Z.)
- Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Lvshun South Road, Dalian 116044, China
| | - Ni Kou
- Department of Oral Prosthodontics, School of Stomatology, Dalian Medical University, Lvshun South Road, Dalian 116044, China; (W.F.); (S.L.); (J.J.); (Y.L.); (H.L.); (S.H.); (E.Z.)
- Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Lvshun South Road, Dalian 116044, China
- Correspondence: (N.K.); (G.M.)
| | - Guowu Ma
- Department of Oral Prosthodontics, School of Stomatology, Dalian Medical University, Lvshun South Road, Dalian 116044, China; (W.F.); (S.L.); (J.J.); (Y.L.); (H.L.); (S.H.); (E.Z.)
- Academician Laboratory of Immune and Oral Development & Regeneration, Dalian Medical University, Lvshun South Road, Dalian 116044, China
- Correspondence: (N.K.); (G.M.)
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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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Rutkūnas V, Gedrimienė A, Auškalnis L, Admakin O, Mangano F. Accuracy of Fixed Implant-Supported Dental Prostheses Additively Manufactured by Metal, Ceramic, or Polymer: A Systematic Review. J Prosthodont 2022; 31:70-87. [PMID: 35313029 DOI: 10.1111/jopr.13449] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2021] [Indexed: 11/29/2022] Open
Abstract
PURPOSE Additive manufacturing (AM) in prosthodontics is used as an alternative to casting or milling. Various techniques and materials are available for the additive manufacturing of the fixed and removable tooth-supported restorations, but there is a lack of evidence on the accuracy of AM fixed implant-supported prostheses. Recent studies investigated the accuracy of ceramic AM prostheses. Therefore, the aim of this systematic review was to evaluate the accuracy of additively manufactured metal, ceramic or polymers, and screw- or cement-retained fixed implant-supported prostheses. MATERIALS AND METHODS Two calibrated investigators performed an electronic search of relevant publications in the English language following selected PICOS criteria and using a well-defined search strategy (latest search date-1st of June, 2021). Based on the exclusion criteria (no control group, less than five samples per group, 3D printing of the implant abutment part, only subjective evaluation of accuracy, etc.) studies were not included in the review. Quantitative data of accuracy evaluation such as marginal gap, strain analysis, and linear measurements was extracted and interpreted. QUADAS-2 tool was used to assess the risk of methodological bias of all included studies. RESULTS Sixteen in vitro studies were selected for the final analysis. Six of the selected studies evaluated screw-retained restorations and 10 cement-retained implant-supported restorations. Only 4 publications concluded that AM restorations were more accurate than conventionally made (cast or milled) ones. The most common finding was that AM restorations were more accurate than cast and demonstrated less or similar accuracy compared to milled ones (n = 10 studies). Detected marginal discrepancies mean values of the AM prosthesis varied from 23 to more than 200 µm, but most of them were categorized as clinically acceptable. CONCLUSIONS AM implant-supported fixed prostheses demonstrate similar accuracy compared to conventional and computer-aided design and computer-aided manufacturing techniques in vitro. Detected inaccuracies of AM restorations do not exceed clinically acceptable limits. Clinical studies with longer follow-up periods are needed to show the reliability of AM prostheses.
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Affiliation(s)
- Vygandas Rutkūnas
- Department of Prosthodontics, Institute of Odontology, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Agnė Gedrimienė
- Department of Prosthodontics, Institute of Odontology, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | | | - Oleg Admakin
- Department of Prevention and Communal Dentistry, Sechenov First State Medical University, Moscow, Russian Federation
| | - Francesco Mangano
- Department of Prevention and Communal Dentistry, Sechenov First State Medical University, Moscow, Russian Federation
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