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Mourad KE, Rashed NHAH, Altonbary GY, Fattah Hegazy SA. Five years of radiographic evaluation for the peri-implant bone changes of all-on-four implant prostheses constructed from different framework materials using different digital construction techniques. BMC Oral Health 2024; 24:910. [PMID: 39112988 PMCID: PMC11308698 DOI: 10.1186/s12903-024-04642-7] [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: 03/12/2024] [Accepted: 07/22/2024] [Indexed: 08/10/2024] Open
Abstract
BACKGROUND There is insufficient evidence recommending a framework material and a CAD/CAM manufacturing technique for mandibular implant-supported prostheses. The study objective was to evaluate the clinical application of different materials and construction techniques used for mandibular All-on-4 prosthesis on circumferential peri-implant bony changes after 5 years. METHODS Thirty-six male patients with all-on-4 mandibular implant-supported prostheses were recalled and divided into three groups. Group PK (patients with frameworks milled from PEEK blocks), Group PSM (patients with frameworks milled from soft metal blocks), and Group SLM (patients with frameworks constructed with additive manufacturing; selective laser melting). The circumferential bone level on all implant faces was assessed with a CBCT. Two-way repeated measures ANOVA was used to compare vertical bone loss (VBL) and horizontal bone loss (HBL) between different groups, implant positions, and observation times followed by Tukey's multiple comparisons. RESULTS For all observation times, there was a significant difference in VBL between groups for both anterior and posterior implants (P < .001). For anterior implants, group PSM showed the lowest VBL while group PK showed the highest for anterior and posterior implants. For all groups, HBL significantly increased after 5 years for both anterior and posterior implants (P < .001). For anterior implants, group PSM showed the highest HBL. For posterior implants, group PK and SLM showed the highest. CONCLUSION Within the study's limitations, mandibular implant-supported fixed frameworks fabricated with either milling from PEEK or soft metal blocks, or additive manufacturing (laser melting technology) exhibited significant vertical and horizontal bone height changes after 5 years. CLINICAL TRIAL REGISTRY NUMBER (NCT06071689) (11/10/2023).
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Affiliation(s)
- Khloud Ezzat Mourad
- Department of Prosthodontics, Faculty of Dentistry, Mansoura University, Mansoura, Egypt.
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2
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Tonin BSH, Fu J, Peixoto RF, Fischer NG, Fernandes RM, Curylofo PA, de Mattos MDGC, Macedo AP, de Almeida RP. An in vitro study using confocal laser scanning microscopy to evaluate the marginal misfits of different implant-supported frameworks. J Prosthodont 2024. [PMID: 38305664 DOI: 10.1111/jopr.13826] [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: 07/31/2023] [Accepted: 01/09/2024] [Indexed: 02/03/2024] Open
Abstract
PURPOSE This study aimed to develop and evaluate a simple, non-destructive method for assessing the misfit and passivity of implant-retained prostheses frameworks. MATERIALS AND METHODS To simulate the rehabilitation of a mandible posterior partially edentulous area using 3-unit screw-retained frameworks supported by two implants were fabricated and divided into the following five groups (n = 10 in each group): OP = one-piece framework cast in Co-Cr with the conventional method (control-group); Co-Cr frameworks sectioned and welded by laser (=LAS) or tungsten inert gas (=TIG); Co-Cr CAD-CAM = milled Co-Cr framework; Zir CAD-CAM = milled zirconia framework. The horizontal |X| and vertical |Y| misfits were measured using confocal laser scanning microscopy with one or both screws tightened. Data were analyzed by a two-way ANOVA with repeated measures and Bonferroni correction (α = 0.05). RESULTS The greatest |X| misfit was observed in the OP group with both screws tightened (290 µm) and one screw tightened (388 and 340 µm). The conventional casting groups sectioned and welded by laser or TIG had lower mean values (235.35 µm, both screws tightened; and 275 µm, one screw tightened) than the OP framework. However, these values still exceeded those of the milled Co-Cr and zirconia frameworks (190 and 216 µm with both screws tightened). Across all reading conditions, every framework subjected to testing consistently maintained vertical |Y| misfit levels below the threshold of 53 µm; however, the milled frameworks exhibited higher vertical misfits than the frameworks obtained by the conventional cast method. CONCLUSIONS The frameworks, whether cast and sectioned with laser welding or milled from Co-Cr, exhibit improved marginal misfit and enhanced passive fit when compared to other fabrication methods. Additionally, the use of confocal laser scanning microscopy is highly effective for passivity and misfit analysis.
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Affiliation(s)
- Bruna S H Tonin
- Department of Dental Material and Prosthesis, Ribeirão Preto School of Dentistry, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Jing Fu
- Department of Prosthodontics, The Affiliated Hospital of Qingdao University, School of Stomatology of Qingdao University, Qingdao, China
| | - Raniel F Peixoto
- Department of Dental Material and Prosthesis, Ribeirão Preto School of Dentistry, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
- Department of Restorative Dentistry, Faculty of Pharmacy, Dentistry and Nursing, Federal University of Ceará (UFC), Fortaleza, Ceará, Brazil
| | - Nicholas G Fischer
- Minnesota Dental Research Center for Biomaterials and Biomechanics, School of Dentistry, University of Minnesota (UMN), Minneapolis, Minnesota, USA
| | - Regina M Fernandes
- Department of Dental Material and Prosthesis, Ribeirão Preto School of Dentistry, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Patrícia A Curylofo
- Department of Dental Material and Prosthesis, Ribeirão Preto School of Dentistry, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Maria da Gloria C de Mattos
- Department of Dental Material and Prosthesis, Ribeirão Preto School of Dentistry, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Ana Paula Macedo
- Department of Dental Material and Prosthesis, Ribeirão Preto School of Dentistry, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Rossana P de Almeida
- Department of Dental Material and Prosthesis, Ribeirão Preto School of Dentistry, University of São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
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Rues S, Tasaka A, Fleckenstein I, Yamashita S, Rammelsberg P, Boehm S, Schwindling FS. Fit and Retention of Cobalt-Chromium Removable Partial Denture Frameworks Fabricated with Selective Laser Melting. J Funct Biomater 2023; 14:416. [PMID: 37623661 PMCID: PMC10456016 DOI: 10.3390/jfb14080416] [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: 06/05/2023] [Revised: 07/28/2023] [Accepted: 08/04/2023] [Indexed: 08/26/2023] Open
Abstract
PURPOSE To evaluate fit and retention of cobalt-chromium removable partial denture (RPD) frameworks fabricated with selective laser melting (SLM). METHODS Three types of framework for clasp-retained RPDs were virtually designed and fabricated using SLM (n = 30). For comparison, 30 additional frameworks were produced using conventional lost-wax casting. A biomechanical model was created, incorporating extracted teeth mounted on flexible metal posts. Using this model, horizontal constraint forces resulting from a misfit were measured using strain gauges, while vertical forces were not recorded. The constraint force components and resultant forces were determined for all abutment teeth, and the maximum retention force during RPD removal from the model was also assessed. For statistical evaluation, the two fabrication methods were analyzed by calculating the means and standard deviations. RESULTS The average horizontal constraint forces showed similar values for both fabrication methods (SLM: 3.5 ± 1.0 N, casting: 3.4 ± 1.6 N). The overall scatter of data for cast RPDs was greater compared to those fabricated using SLM, indicating a better reproducibility of the SLM process. With regard to retention, the intended retention force of 5-10 N per abutment tooth was not attained in one of the cast groups, while it was consistently achieved in all SLM groups. CONCLUSIONS This in vitro study found that SLM is a promising option for the manufacture of cobalt-chromium RPD frameworks in terms of fit and retention.
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Affiliation(s)
- Stefan Rues
- Department of Prosthodontics, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Akinori Tasaka
- Department of Removable Prosthodontics, Tokyo Dental College, Tokyo 101-0061, Japan
| | - Isabella Fleckenstein
- Department of Prosthodontics, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Shuichiro Yamashita
- Department of Removable Prosthodontics, Tokyo Dental College, Tokyo 101-0061, Japan
| | - Peter Rammelsberg
- Department of Prosthodontics, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Sophia Boehm
- Department of Prosthodontics, Heidelberg University Hospital, 69120 Heidelberg, Germany
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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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Abu Ghofa A, Önöral Ö. An assessment of the passivity of the fit of multiunit screw-retained implant frameworks manufactured by using additive and subtractive technologies. J Prosthet Dent 2023; 129:440-446. [PMID: 34294420 DOI: 10.1016/j.prosdent.2021.06.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 06/09/2021] [Accepted: 06/09/2021] [Indexed: 10/20/2022]
Abstract
STATEMENT OF PROBLEM The lack of passive fit in implant-supported restorations can lead to mechanical and biological complications and compromise the longevity of the prosthesis. The manufacturing technique and evaluation site are factors that may affect the passive fit of multiunit screw-retained implant frameworks. However, scientific information regarding this issue is lacking. PURPOSE The purpose of this in vitro study was to investigate the effect of manufacturing technique and evaluation site on the passive fit of multiunit screw-retained implant frameworks. MATERIAL AND METHODS Two multiunit implant analogs were placed into the right second premolar and second molar sites of a mandibular typodont model. A total of 50 3-unit Co-Cr frameworks were fabricated with 3 indirect (conventional technique, polymethyl methacrylate milling, stereolithography) and 2 direct techniques (selective laser melting and soft alloy milling). The patterns obtained by indirect techniques were subsequently cast. The Sheffield test was used for the assessment. Digital images of the sites were obtained by using a stereomicroscope at ×40 magnification, and the measurement points (n=10 for each site) were examined to record the vertical marginal discrepancy values (μm) with the aid of a measuring software program. The collected data were subjected to the 2-way ANOVA and Tukey honestly significant difference test (α=.05). RESULTS The influence of the manufacturing technique (variable 1) on the vertical marginal discrepancy values was statistically significant (P<.001). However, the evaluation site (variable 2) (P=.097) and the interaction of the variables (P=.960) were not statistically significant. The lowest misfit values were observed for selective laser melting (74.2 ±20.5 μm) followed by stereolithography (92.8 ±23.9 μm), soft alloy milling (108.4 ±12.0 μm), polymethyl methacrylate milling (116.7 ±17.0 μm), and conventional technique (137.5 ±18.9 μm). The vertical marginal discrepancy values of the selective laser melting group were significantly lower than those of all other groups (P<.05). CONCLUSIONS The manufacturing technique significantly affected the passive fit. selective laser melting-fabricated frameworks demonstrated superior fitting accuracy. Among the indirect techniques, stereolithography-fabricated frameworks revealed the lowest misfit values. The vertical marginal discrepancy values of all manufacturing groups were within the range of clinical acceptability (<150 μm).
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Affiliation(s)
- Amr Abu Ghofa
- Research Assistant, Department of Prosthetic Dentistry, Faculty of Dentistry, Near East University, Nicosia, Turkey.
| | - Özay Önöral
- Assistant Professor, Department of Prosthetic Dentistry, Faculty of Dentistry, Near East University, Nicosia, Turkey
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Aydın N, Ekren O, Kocak EF, Ucar Y. Comparison of the Marginal and Internal Discrepancy of Metal-Ceramic Restorations Produced by Milling for Soft Metal, Direct Metal Laser Sintering and Casting Methods: An In Vitro Study. JOURNAL OF ADVANCED ORAL RESEARCH 2022. [DOI: 10.1177/23202068221103980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Aim: To evaluate the effect of ceramic firing cycles on the internal and marginal discrepancy of restorations fabricated using conventional lost wax casting (LW), direct metal laser sintering (DMLS), and milling for soft metal (MS). Materials and Methods: A total of 45 restorations were produced by LW, DMLS, and MS methods ( n = 15), according to the digital impression on the metal die representing the prepared first molar. The internal discrepancy (ID) was measured through the silicon weight method and the marginal discrepancy (MD) was measured using a light microscope. ID and MD measurements were repeated following the metal manufacturing, ceramic application, and glazing. Statistical analyses were conducted by means of two-way analysis of variance and Tukey-HSD ( α = 0.05) tests. Results: Statistically significant differences were found between the fabrication methods ( P ≤ 0.001) both for MD and ID. The mean MD values of the restorations were 31.4 ± 13.8 µm for MS, 20.8 ± 14.4 µm for LW, and 7.3 ± 6 µm for DMLS. A statistically significant increase was observed in the mean MD values of metal frameworks ( P ≤ 0.001) following ceramic and glaze applications. However, no statistically significant difference was found between the ceramic and the glaze applied stages ( P = .072). The mean ID values were 37 ± 5.7 mg for LW, 28 ± 6.1 mg for DMLS, and 21.6 ± 7.3 mg for MS. Unlike the manufacturing method, ceramic firing cycles had no effects on the ID ( P > 0.05). Conclusion: MS had the highest mean MD, but it had the lowest ID. The ceramic firing had a significantly negative effect only on MD.
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Affiliation(s)
- Nazlı Aydın
- Department of Prosthetic Dentistry, Faculty of Dentistry, Cukurova University, Balcali, Adana, Turkey
- Abdi Sutcu Vocational School of Health Services, Cukurova University, Balcali, Adana, Turkey
| | - Orhun Ekren
- Department of Prosthetic Dentistry, Faculty of Dentistry, Cukurova University, Balcali, Adana, Turkey
- Department of Advanced Materials and Nanotechnology, Institute of Natural and Applied Sciences, Cukurova University, Balcali, Adana, Turkey
| | - Elif Figen Kocak
- Department of Prosthetic Dentistry, Faculty of Dentistry, Cukurova University, Balcali, Adana, Turkey
- Abdi Sutcu Vocational School of Health Services, Cukurova University, Balcali, Adana, Turkey
| | - Yurdanur Ucar
- Private Dental Practice, Motto Oral and Dental Health Polyclinic, Antalya, Turkey
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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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New generation CAD-CAM materials for implant-supported definitive frameworks fabricated by using subtractive technologies. BIOMED RESEARCH INTERNATIONAL 2022; 2022:3074182. [PMID: 35281596 PMCID: PMC8906986 DOI: 10.1155/2022/3074182] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 01/05/2022] [Accepted: 02/02/2022] [Indexed: 12/31/2022]
Abstract
Innovations in digital manufacturing enabled the fabrication of implant-supported fixed dental prostheses (ISFDPs) in a wide variety of recently introduced materials. Computer-aided design and computer-aided manufacturing (CAD-CAM) milling allows the fabrication of ISFDPs with high accuracy by reducing the fabrication steps of large-span frameworks. The longevity of ISFDPs depends on the overall mechanical properties of the framework material including its fit, and the physical properties of the veneering material and its bond with the framework. This comprehensive review summarizes the recent information on millable CAD-CAM framework materials such as pre-sintered soft alloys, fiber-reinforced composite resins, PEEK, and PEKK in high-performance polymer family, and 4Y-TZP. Even though promising results have been obtained with the use of new generation millable CAD-CAM materials for ISFDPs, clinical studies are lacking and future research should focus on the overall performance of these millable materials in both static and dynamic conditions.
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Haroyan-Darbinyan E, Romeo-Rubio M, Río-Highsmith JD, Lynch CD, Castillo-Oyagüe R. Fracture resistance of cantilevered full-arch implant-supported hybrid prostheses with carbon fiber frameworks after thermal cycling. J Dent 2021; 116:103902. [PMID: 34822914 DOI: 10.1016/j.jdent.2021.103902] [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: 10/10/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES This in vitro study aimed to find the best combination of mesostructure and veneering materials for full-arch implant-supported hybrid prostheses (HPs) in terms of the fracture resistance (FR) of their cantilevers. METHODS Three groups (n = 5 each) of maxillary HPs were fabricated: Group-1 (CC-A, control): Co-Cr frameworks coated with acrylic resin; Group-2 (CF-A): carbon fiber veneered with acrylic resin; and Group-3 (CF-R): carbon fiber coated with composite resin. All specimens were submitted to 5,000 thermal cycles (5 °C - 55 °C, dwell time: 30 s), and subjected to a single cantilever bending test in a universal testing machine (crosshead speed: 0.5 mm/min) until failure. The fracture pattern was assessed using stereo microscope and SEM. The one-way ANOVA and Bonferroni tests were run (α= 0.05). RESULTS The FR yielded significant differences among the three groups (p< 0.001). CC-A samples reached the highest FR values (p ≤ 0.001), whereas both CF-A and CF-R HPs exhibited the comparably (p = 0.107) lowest FR. CC-A specimens failed cohesively (100%): mostly without chipping (80%). CF-A mesostructures were always broken at the connections of the distal implants. CF-R prostheses often failed adhesively (80%). CONCLUSIONS The HPs made of Co-Cr veneered with acrylic demonstrated the best mechanical behavior, being the only group whose 13-mm long cantilevers exceeded the clinically acceptable FR of 900 N. The HPs constructed with carbon fiber frameworks showed, additionally, more unfavorable fracture patterns. CLINICAL SIGNIFICANCE For HPs with cantilevers up to 13 mm, Co-Cr mesostructures coated with acrylic may represent the optimum combination of materials.
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Affiliation(s)
| | - Marta Romeo-Rubio
- Faculty of Dentistry, Complutense University of Madrid (U.C.M.), Madrid, Spain.
| | | | - Christopher D Lynch
- University Dental School & Hospital/University College Cork, Wilton, Cork, Ireland.
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Effect of different design of abutment and implant on stress distribution in 2 implants and peripheral bone: A finite element analysis study. J Prosthet Dent 2021; 126:664.e1-664.e9. [PMID: 33573834 DOI: 10.1016/j.prosdent.2020.09.058] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/27/2020] [Accepted: 09/28/2020] [Indexed: 11/23/2022]
Abstract
STATEMENT OF PROBLEM How adjacent dental implants with different sizes, designs, and abutment connection shapes affect stress on the prosthetic structure is unclear. PURPOSE The purpose of this finite element analysis (FEA) study was to analyze stress distribution around bone and around 2 implants with different sizes, diameters, shapes, and loading directions placed next to each other in splinted and unsplinted prostheses. MATERIAL AND METHODS On 3D FEA models representing the posterior right lateral segment of the mandible, 1 implant (Ø3.5×12 mm) and 1 implant (Ø5.5×8 mm) were placed adjacent. Three different contemporary implant models were created with different teeth, pitch, spiral numbers, and self-taping features, and different abutments for them were modeled in 3D. The implant-abutment connection was internal hexagonal (MIH), stepped conical (MSC), and internal conical (MIC). Vertical and oblique loads of 365 N for molar teeth and of 200 N for premolar teeth were applied as boundary conditions to the cusp ridges and grooves in a nonlinear FEA. RESULTS The MIH implants resulted in improved stress conditions. According to the von Mises stresses occurring on the screw, abutment, and implant, especially under oblique loads, MIH was exposed to less stress than MSC, and MSC was exposed to less stress than MIC. CONCLUSIONS When a standard implant and a short implant were placed adjacent and splinted by crowns, the implants, abutments, and screws had unfavorable stress levels; therefore, adjacent splinted implants should be of similar size. The form of the implant-abutment junction is also an important factor affecting stress.
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Pan Y, Tsoi JKH, Lam WYH, Pow EHN. Implant framework misfit: A systematic review on assessment methods and clinical complications. Clin Implant Dent Relat Res 2020; 23:244-258. [PMID: 33331058 DOI: 10.1111/cid.12968] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 11/25/2020] [Accepted: 11/26/2020] [Indexed: 11/28/2022]
Abstract
BACKGROUND The fit of implant-supported prostheses is of prime importance for the long-term success of implant therapy. PURPOSE This systematic review aimed to evaluate recent evidence on current techniques for assessing implant-framework misfit, its associated strain/stress, and whether these misfits are related to mechanical, biological, and clinical consequences. MATERIALS AND METHODS An electronic search for publications from January 2010 to October 2020 was performed using the Pubmed, Embase, Web of Science, and Cochrane Library databases with combined keywords on implant-framework misfit assessments and related clinical complications. Inclusion and exclusion criteria were applied. After full-text analyses, data extraction was implemented on current techniques of misfit assessment and the relationship between the misfit and the induced strain/stress. RESULTS A total of 3 in vivo and 92 in vitro studies were selected, including 47 studies on quantifying the degree of implant-framework misfit with dimensional techniques, 24 studies measuring misfit-induced strain/stress with modeling techniques, and 24 studies using both methods. The technical details, advantages, and limitations of each technique were illustrated. The correlation between the implant-framework misfit and the induced strain/stress has been revealed in vitro, while that with the biological complications and implant/prostheses failure was weak in clinical studies. CONCLUSIONS Dimensional and modeling techniques are available to measure the implant-framework misfit. The passivity of implant-supported fixed prostheses appeared related to the induced strain/stress, but not the clinical complications. Further studies combining three-dimensional (3D) assessments using dimensional and modeling techniques was needed.
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Affiliation(s)
- Yu Pan
- Faculty of Dentistry, The University of Hong Kong, Hong Kong special administrative region, China
| | - James K H Tsoi
- Faculty of Dentistry, The University of Hong Kong, Hong Kong special administrative region, China
| | - Walter Y H Lam
- Faculty of Dentistry, The University of Hong Kong, Hong Kong special administrative region, China
| | - Edmond H N Pow
- Faculty of Dentistry, The University of Hong Kong, Hong Kong special administrative region, China
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12
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Figueras-Alvarez O, Cantó-Navés O, Real-Voltas F, Roig M. Protocol for the clinical assessment of passive fit for multiple implant-supported prostheses: A dental technique. J Prosthet Dent 2020; 126:727-730. [PMID: 33143900 DOI: 10.1016/j.prosdent.2020.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 10/01/2020] [Accepted: 10/01/2020] [Indexed: 02/07/2023]
Abstract
With monolithic materials and the new technologies for framework production, assessment of passive fit before fabrication of the definitive prosthesis or its framework is essential to avoid prosthesis remakes. This article describes an updated clinical protocol to assess passive fit during the prosthesis fabrication process through the systematic use of tactile feel while tightening the retaining screws, the visual or radiographic evaluation when performing the 1-screw or Sheffield fit test, and the torque/time graph obtained during the placement of the implant- or abutment-retaining screws with a torque-controlled surgical motor.
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Affiliation(s)
- Oscar Figueras-Alvarez
- Associate Professor, Department of Prosthodontics, Universitat Internacional de Catalunya, Barcelona, Spain.
| | - Oriol Cantó-Navés
- Associate Professor, Department of Prosthodontics, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Francisco Real-Voltas
- Associate Professor, Department of Prosthodontics, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Miguel Roig
- Professor and Chairman, Department of Prosthodontics, Universitat Internacional de Catalunya, Barcelona, Spain
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Shah S, Nallaswamy D, Ganapathy D. Marginal Accuracy of Milled Versus Cast Cobalt Chromium Alloys in Long Span Implant-Supported Frameworks: A Systematic Review and Meta-analysis. JOURNAL OF ADVANCED ORAL RESEARCH 2020. [DOI: 10.1177/2320206820952303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Aim: To assess if milled cobalt chromium (Co-Cr) alloy offers significantly better marginal accuracy than cast Co-Cr alloy for screw-retained long-span dental implant framework. Materials and Methods: A search PICO was formulated using suitable keywords and an electronic search was initiated. The databases of PubMed, Cochrane Library, Google Scholar and Embase were searched for related articles. Bibliographies of randomised control trials and reviews, identified in the electronic search, were analysed for studies published outside the electronically searched journals. Electronic search identified 26 studies. A total of 16 studies were eliminated after reading the abstracts. Out of the remaining 10 studies, 3 were eliminated based on the inclusion and exclusion criteria, and finally 7 studies were finalised for systematic review. Results Data were extracted from the included studies and analysed. The obtained data were suitable for meta-analysis, which showed an overall effect size z = 4.97 ( P < .001) at 95% CI showing a significant statistical difference between milled and cast Co-Cr frameworks. Conclusion: Milled cobalt chromium frameworks are significantly more accurate than cast frameworks for long-span implant-supported frameworks used in dental prosthetic rehabilitation. More randomized controlled trials need to be conducted with a larger sample size to get a more authentic conclusion in a clinical scenario.
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Affiliation(s)
- Simone Shah
- Department of Prosthodontics and Implant Dentistry, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamil Nadu, India
| | - Deepak Nallaswamy
- Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamil Nadu, India
| | - Dhanraj Ganapathy
- Department of Prosthodontics and Implant Dentistry, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamil Nadu, India
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Kaczmarek B, Mazur O. Collagen-Based Materials Modified by Phenolic Acids-A Review. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E3641. [PMID: 32824538 PMCID: PMC7476000 DOI: 10.3390/ma13163641] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 02/06/2023]
Abstract
Collagen-based biomaterials constitute one of the most widely studied types of materials for biomedical applications. Low thermal and mechanical parameters are the main disadvantages of such structures. Moreover, they present low stability in the case of degradation by collagenase. To improve the properties of collagen-based materials, different types of cross-linkers have been researched. In recent years, phenolic acids have been studied as collagen modifiers. Mainly, tannic acid has been tested for collagen modification as it interacts with a polymeric chain by strong hydrogen bonds. When compared to pure collagen, such complexes show both antimicrobial activity and improved physicochemical properties. Less research reporting on other phenolic acids has been published. This review is a summary of the present knowledge about phenolic acids (e.g., tannic, ferulic, gallic, and caffeic acid) application as collagen cross-linkers. The studies concerning collagen-based materials with phenolic acids are summarized and discussed.
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Affiliation(s)
- Beata Kaczmarek
- Department of Biomaterials and Cosmetics Chemistry, Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarin 7, 87-100 Toruń, Poland;
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