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ElShamoty YK, Sadeqi HA, Baig MR. Effect of connector height and retainer occlusal thickness on the fracture resistance of posterior 4-unit monolithic 5Y-TZP fixed partial dentures after thermomechanical aging. J Prosthet Dent 2024; 131:933.e1-933.e7. [PMID: 38429151 DOI: 10.1016/j.prosdent.2024.01.033] [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: 09/21/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 03/03/2024]
Abstract
STATEMENT OF PROBLEM The connector height and retainer occlusal thickness of fixed partial dentures (FPDs) may affect restoration longevity. PURPOSE The purpose of this in vitro study was to determine and compare the fracture resistance of 4-unit monolithic 5% yttria tetragonal zirconia polycrystal (5Y-TZP) FPDs made with different connector heights and retainer occlusal thicknesses after thermomechanical aging. MATERIAL AND METHODS Forty test metal dies were duplicated from a master metal die containing 2 anatomic abutment preparations of the mandibular right first premolar and second molar for a 4-unit FPD. The dies were divided into 2 groups of 20 each for the fabrication of 4-unit FPDs, with 2-mm and 4-mm uniform connector heights at all 3 connectors, resulting in 6.3-mm2 and 12.6-mm2 connector areas. Each of these groups was further divided into 2 subgroups based on the occlusal thickness of the 2 retainers of 1 mm and 2 mm (n=10). Polyvinyl siloxane impressions of the test metal dies were made and poured in Type V dental stone. Laboratory scans were performed on all the stone dies, and 40 5Y-TZP FPDs (Ceramill Zolid FX) were designed and fabricated. Subsequently, all the FPDs were luted on to the metal dies with a self-adhesive resin cement. The FPDs were preloaded (400 000 mechanical cycles; 4000 thermocycles) using a mastication simulator and tested for axial compressive strength. Two-way analysis of variance (ANOVA) was used to examine the effect of connector and occlusal thicknesses on the fracture load (α=.05). The data were further assessed using the post hoc Tukey HSD multiple comparison test (α=.05). RESULTS The mean fracture load values were between 737 N and 1563 N. Significant differences in the mean fracture load were found between the connector heights (601 N; P<.001) and occlusal thicknesses (225 N; P=.002), but the interaction of the 2 factors was not significant (P=.132) The Tukey post hoc analysis showed significant differences between the connector thicknesses groups (P<.01), but the occlusal thicknesses were found to be similar for the same connector height (P=.609) CONCLUSIONS: Connector height and occlusal retainer thickness influenced the fracture load of 4-unit monolithic 5Y-TZP FPDs after thermomechanical aging.
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Affiliation(s)
- Yousef Khaled ElShamoty
- Graduate student, Dental Materials Science, Department of Bioclinical Sciences, College of Dentistry, Kuwait University, Kuwait City, Kuwait; and Ministry of Health, Kuwait
| | - Haneen Adnan Sadeqi
- Senior Dental Technician, Department of Restorative Sciences, College of Dentistry, Kuwait University, Kuwait City, Kuwait
| | - Mirza Rustum Baig
- Associate Professor, Department of Restorative Sciences (Prosthodontics), College of Dentistry, Kuwait University, Kuwait City, Kuwait.
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Subsomboon C, Urapepon S. Effect of connector configuration on the fracture load in conventional and translucent zirconia three-unit fixed dental prostheses. J Adv Prosthodont 2023; 15:171-178. [PMID: 37662855 PMCID: PMC10471503 DOI: 10.4047/jap.2023.15.4.171] [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: 04/03/2023] [Revised: 06/19/2023] [Accepted: 08/10/2023] [Indexed: 09/05/2023] Open
Abstract
PURPOSE The purpose of this study was to determine the effect of the connector configuration on the fracture load in conventional and translucent zirconia of three-unit fixed dental prostheses (FDPs). MATERIALS AND METHODS Six different three-unit FDPs were prepared (n = 6) from three types of zirconia (3Y-TZP (Katana ML®), 4Y-TZP (Katana STML®), and 5Y-TZP (Katana UTML®)) in combination with two connector configurations (4 × 2.25, 3 × 3 mm). The Co-Cr master models were scanned, and the FDPs were designed and fabricated using CAD-CAM. The FDPs were cemented on the metal model and then loaded with a UTM at a crosshead speed of 1 mm/min until failure. Two-way ANOVA and Tukey's test were used for statistical analysis (α = .05). RESULTS Fracture loads of 3Y-TZP (2740.6 ± 469.2 and 2718.7 ± 339.0 N for size 4 × 2.25 mm and 3 × 3 mm, respectively) were significantly higher than those of 4Y-TZP (1868.3 ± 281.6 and 1663.6 ± 372.7 N, respectively) and 5Y-TZP (1588.0 ± 255.0 and 1559.1 ± 110.0 N, respectively) (P < .05). No significant difference was found between fracture loads of 4Y-TZP and 5Y-TZP (P > .05). The connector configuration within 9 mm2 was found to have no effect on the fracture loads on all three types of zirconia (P > .05). CONCLUSION Fracture loads of three-unit FDPs were affected by the type of zirconia. The fracture loads of conventional zirconia were higher than those of translucent zirconia. However, it was not affected by the connector configuration when the connector had a cross-sectional area of 9 mm2.
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Affiliation(s)
- Chonticha Subsomboon
- Department of Prosthodontics, Faculty of Dentistry, Mahidol University, Bangkok, Thailand
| | - Somchai Urapepon
- Department of Prosthodontics, Faculty of Dentistry, Mahidol University, Bangkok, Thailand
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Marini G, Saldanha da Rosa L, Machado PS, Silvestre FA, Valandro LF, Feitosa VP, Pereira GKR, Bacchi A. Fatigue performance analysis of strength-graded zirconia polycrystals for monolithic three-unit implant-supported prostheses. J Mech Behav Biomed Mater 2023; 140:105736. [PMID: 36801783 DOI: 10.1016/j.jmbbm.2023.105736] [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: 11/05/2022] [Revised: 02/10/2023] [Accepted: 02/13/2023] [Indexed: 02/16/2023]
Abstract
The aim of this study was to evaluate the fatigue behavior of strength-graded zirconia polycrystals used as monolithic three-unit implant-supported prosthesis; complementarily, crystalline phase and micromorphology were also assessed. Fixed prostheses with 3 elements supported by 2 implants were confectioned, as follows: Group 3Y/5Y - monolithic structures of a graded 3Y-TZP/5Y-TZP zirconia (IPS e.max® ZirCAD PRIME); Group 4Y/5Y - monolithic structures of a graded 4Y-TZP/5Y-TZP zirconia (IPS e.max® ZirCAD MT Multi); Group Bilayer - framework of a 3Y-TZP zirconia (Zenostar T) veneered with porcelain (IPS e.max Ceram). The samples were tested for fatigue performance with step-stress analysis. The fatigue failure load (FFL), the number of cycles required until failure (CFF), and the survival rates in each cycle were recorded. The Weibull module was calculated and the fractography analyzed. The crystalline structural content via Micro-Raman spectroscopy and the crystalline grain size via Scanning Electron microscopy were also assessed for graded structures. Group 3Y/5Y showed the highest FFL, CFF, probability of survival, and reliability (based on Weibull modulus). Group 4Y/5Y showed significantly superior FFL and probability of survival than group bilayer. Fractographic analysis revealed catastrophic flaws in the monolithic structure and cohesive fracture of porcelain in bilayer prostheses, all originating from the occlusal contact point. The graded zirconia presented small grain size (≤0.61 μm), with the smallest values at the cervical region. The main composition of graded zirconia was of grains at tetragonal phase. The strength-graded monolithic zirconia, especially the 3Y-TZP/5Y-TZP, showed to be promising for use as monolithic three-unit implant-supported prosthesis.
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Affiliation(s)
- Gabriel Marini
- Post-Graduate Program in Dentistry, Atitus Education, Passo Fundo, RS, Brazil
| | - Lucas Saldanha da Rosa
- Post-Graduate Program in Dental Sciences, Federal University of Santa Maria (UFSM), Santa Maria, RS, Brazil
| | - Pablo Soares Machado
- Post-Graduate Program in Dental Sciences, Federal University of Santa Maria (UFSM), Santa Maria, RS, Brazil
| | | | - Luiz Felipe Valandro
- Post-Graduate Program in Dental Sciences, Federal University of Santa Maria (UFSM), Santa Maria, RS, Brazil
| | - Victor Pinheiro Feitosa
- Post-Graduate Program in Dentistry, Paulo Picanço School of Dentistry (FACPP), Fortaleza, CE, Brazil
| | | | - Atais Bacchi
- Post-Graduate Program in Dentistry, Paulo Picanço School of Dentistry (FACPP), Fortaleza, CE, Brazil.
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Bataineh K, Al Janaideh M, Abu-Naba'a LA. Fatigue Resistance of 3-Unit CAD-CAM Ceramic Fixed Partial Dentures: An FEA Study. J Prosthodont 2022; 31:806-814. [PMID: 35118758 DOI: 10.1111/jopr.13487] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 01/25/2022] [Indexed: 01/04/2023] Open
Abstract
PURPOSE To estimate the fatigue life of 3-unit molar fixed partial dentures (FPDs) made from two different monolithic ceramic systems, zirconia cercon (ZC) and lithium disilicate (LD). The effect of the connector size on the fatigue resistance of the monolithic FPD was also investigated. METHODS Two models for the FPDs were built, a 3-unit all-ceramic and a porcelain-fused-to-metal. The porcelain-fused-to-metal FPD model was used as the control. Actual 3-unit FPDs (replacing the second lower premolar) were constructed using a computer aided design and computer-aided manufacturing (CAD-CAM) system. Finite element analysis (FEA) was executed. A hemispherical indenter was used to simulate occlusal load. The occlusal load phase of the chewing cycle was applied at the premolar pontic. RESULTS The failure location for the monolithic FPD was always located at the distal connector. Connector size played a key role in determining the long-term survival of the prosthesis. The fatigue resistance was predicted to be 670 N for the ZC with a connector size 4 × 3 mm, while it was only 226 N for LD. As for porcelain-fused-to-metal (PFM), FEA predicts that fatigue resistance can reach up to 770 N. Under the cyclic load of 670 N, the fatigue life for the zirconia FPD with connector size 4 × 3 mm was 2.23 × 106 cycles while it survived only 3.1 × 105 cycles when the connector was reduced to 3.5 × 2.5 mm. The angle of the oblique load has a significant effect on the stress distribution. CONCLUSION 3-unit monolithic FPDs made of ZC have superior fatigue performance compared to those made of LD. The fatigue life of the zirconia FPD was about three times longer than that made of LD with a connector size of 4 mm × 3 mm. The survival rates of ZC FPDs are comparable to porcelain-fused-to-metal. A significant reduction in fatigue strength is predicted for reduced connector size. Therefore, it is necessary to establish general guidelines for the minimum connector size.
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Affiliation(s)
- Khaled Bataineh
- Department of Mechanical Engineering, Jordan University of Science and Technology, Irbid, Jordan
| | - Mohammad Al Janaideh
- Department of Mechanical Engineering, Jordan University of Science and Technology, Irbid, Jordan
| | - Layla A Abu-Naba'a
- Department of Prosthodontics, Jordan University of Science and Technology, Irbid, Jordan
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Influence of Resin Cement Thickness and Elastic Modulus on the Stress Distribution of Zirconium Dioxide Inlay-Bridge: 3D Finite Element Analysis. Polymers (Basel) 2021; 13:polym13223863. [PMID: 34833162 PMCID: PMC8625147 DOI: 10.3390/polym13223863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/01/2021] [Accepted: 11/04/2021] [Indexed: 11/16/2022] Open
Abstract
The mechanical properties and the thickness of the resin cement agents used for bonding inlay bridges can modify the clinical performance of the restoration such as debonding or prosthetic materials fracture. Thus, the aim of this study was to evaluate the stress distribution and the maximum strain generated by resin cements with different elastic moduli and thicknesses used to cement resin-bonded fixed partial denture (RBFPD). A three-dimensional (3D) finite element analysis (FEA) was used, and a 3D model was created based on a Cone-Beam Computed Tomography system (CBCT). The model was analyzed by the Ansys software. The model fixation occurred at the root of the abutment teeth and an axial load of 300 N was applied on the occlusal surface of the pontic. The highest stress value was observed for the Variolink 0.4 group (1.76 × 106 Pa), while the lowest was noted for the Panavia 0.2 group (1.07 × 106 Pa). Furthermore, the highest total deformation value was found for the Variolink 0.2 group (3.36 × 10-4 m), while the lowest was observed for the Panavia 0.4 group (2.33 × 10-4 m). By means of this FEA, 0.2 mm layer Panavia F2.0 seemed to exhibit a more favorable stress distribution when used for cementation of posterior zirconium-dioxide-based RBFPD. However, both studied materials possessed clinically acceptable properties.
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Hafezeqoran A, Koodaryan R, Hemmati Y, Akbarzadeh A. Effect of connector size and design on the fracture resistance of monolithic zirconia fixed dental prosthesis. J Dent Res Dent Clin Dent Prospects 2021; 14:218-222. [PMID: 33575010 PMCID: PMC7867680 DOI: 10.34172/joddd.2020.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 06/12/2020] [Indexed: 11/09/2022] Open
Abstract
Background. Designing a high strength all-ceramic fixed partial denture with favorable esthetics can be challenging for clinicians; this study aimed to evaluate the effect of connector size and design on the fracture resistance of monolithic zirconia fixed dental prostheses.
Methods. Two groups of twenty 3-unit monolithic zirconia (Sirona inCoris TZI, Sirona Dental Systems GmbH) bridges, extending from the mandibular first premolar to the first molar with different connector sizes (9 mm2 and 12 mm2), were divided into two subgroups with different connector designs (round and sharp). The specimens were subjected to the three-point bending test to obtain the fracture-bearing load. The results were reported using descriptive statistics (mean ± standard deviation). Mann-Whitney U test was used to compare the fracture load in two types of designs for each connector size and two connector size types for each connector design. The significance level was considered at P<0.05.
Results. The minimum failure load was related to the group with a 9-mm2 connector size and a sharp embrasure design (1054.4±133.89 N), and the highest mean value belonged to the group with 12-mm2 connector size and rounded embrasure design (1599.8±167.09 N). Mann-Whitney U test indicated a significant difference between the mean failure load of the rounded and sharp embrasure designs in the 9-mm2 connector size (P =0.007). However, the difference was insignificant in the 12-mm2 connector size (P =0.075).
Conclusion. Sharp embrasure design is not recommended for high-stress areas with restricted occlusogingival height. A 9-mm2 connector size for 3-unit monolithic zirconia fixed dental prosthesis (FDP), which is recommended by the manufacturer, should be used more cautiously
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Affiliation(s)
- Ali Hafezeqoran
- Department of Prosthodontics, Dental faculty, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Roodabeh Koodaryan
- Department of Prosthodontics, Dental faculty, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Yasser Hemmati
- Department of Prosthodontics, Dental faculty, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ayshin Akbarzadeh
- Department of Prosthodontics, Dental faculty, Tabriz University of Medical Sciences, Tabriz, Iran
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Ahmed MS, Reddy KM, Shastry YM, Aditya SV, Babu PJ. Evaluation of flexural strength of Zirconia using three different connector designs: An in vitro study. J Indian Prosthodont Soc 2020; 20:285-289. [PMID: 33223698 PMCID: PMC7654207 DOI: 10.4103/jips.jips_68_20] [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: 02/17/2020] [Revised: 04/10/2020] [Accepted: 05/20/2020] [Indexed: 12/04/2022] Open
Abstract
Aim: The aim of this study is to evaluate the flexural strength of zirconia using three different connector designs under vertical and oblique loads. Setting and Design: Invitro - analytical study. Materials and Methods: For simulating zirconia fixed partial prosthesis, a specimen with three octagonal cylinders connected with each other was designed. Each face of the octagon was 3.75 mm ± 0.1 mm, and the total width was 9 mm ± 0.1 mm with a standard connector area of 10 mm2 at cross-section. Three different connector designs, i.e., round, oval, and triangular were milled. Universal testing machine was used to test flexural strength with vertical and oblique forces. Statistical Analysis Used: Intergroup comparison of flexural strength was made using Descriptive statistics (1) one-way ANOVA, Bonferroni's post hoc test (2) Kruskal–Wallis test. The confidence interval was set at 95%, P < 0.05 was considered statistically significant for both the tests. Results: The highest flexural strength was observed in the triangle connector with vertical forces and lowest with oblique forces. Conclusions: Triangle connector design proved to be better than round and oval connectors on the application of vertical loads. Round connector design proved to be better than triangle and oval connector on application of oblique loads.
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Affiliation(s)
| | | | - Y Mahadev Shastry
- Department of Prosthodontics, Sri Sai College of Dental Surgery, Vikarabad, Telangana, India
| | - S Venkat Aditya
- Department of Prosthodontics, Sri Sai College of Dental Surgery, Vikarabad, Telangana, India
| | - P Jayakrishna Babu
- Department of Prosthodontics, Sri Sai College of Dental Surgery, Vikarabad, Telangana, India
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Noda M, Omori S, Nemoto R, Sukumoda E, Takita M, Foxton R, Nozaki K, Miura H. Strain analysis of anterior resin-bonded fixed dental prostheses with different thicknesses of high translucent zirconia. J Dent Sci 2020; 16:628-635. [PMID: 33854712 PMCID: PMC8025231 DOI: 10.1016/j.jds.2020.10.002] [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: 09/02/2020] [Revised: 10/07/2020] [Indexed: 12/05/2022] Open
Abstract
Background/purpose High translucent zirconia has been used as a new monolithic zirconia prosthesis, which has the potential to make anterior resin-bonded fixed dental prostheses (RBFDPs) without veneering porcelain. However, it is unclear whether the RBFDPs retainer can be thinned as much as conventional zirconia RBFDPs. The aim of this study was to assess the usability of high translucent zirconia RBFDPs with a thin retainer thickness by evaluating differences in retainer thickness on the surface strain. Materials and methods A model with a missing upper lateral incisor was used. The abutment teeth were upper central incisor and canine. Three types of RBFDPs were fabricated as follows: metal RBFDPs with a retainer thickness of 0.8 mm (0.8M), and high translucent zirconia RBFDPs with a retainer thicknesses of 0.8 and 0.5 mm (0.8Z, 0.5Z) (n = 10). The fitness of the margins was evaluated by the silicone replica technique. The surface strain of each retainer under static loading was measured and statistically analyzed using a t-test with Bonferroni correction. Results The marginal fitness of all RBFDPs was under 76.1 μm, which was clinically acceptable. Each strain of the 0.8Z and 0.5Z groups was significantly lower than that of the 0.8M (p < 0.05). There was no difference in strain of the zirconia RBFDPs even if the retainer thickness was changed. Conclusion Our results suggest that the high translucent zirconia RBFDPs can be manufactured with a retainer thickness of 0.5 mm, which reduces the amount of tooth preparation compared to the metal RBFDPs.
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Affiliation(s)
- Michiko Noda
- Department of Fixed Prosthodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Satoshi Omori
- Department of Fixed Prosthodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Reina Nemoto
- Department of Fixed Prosthodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Erika Sukumoda
- Department of Fixed Prosthodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Mina Takita
- Department of Fixed Prosthodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Richard Foxton
- Restorative Dentistry, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Kosuke Nozaki
- Department of Fixed Prosthodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Hiroyuki Miura
- Department of Fixed Prosthodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
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Shetty R, Shoukath S, Shetty NHG, Shetty SK, Dandekeri S, Ragher M. A Novel Design Modification to Improve Flexural Strength of Zirconia Framework: A Comparative Experimental In Vitro Study. J Pharm Bioallied Sci 2020; 12:S495-S503. [PMID: 33149511 PMCID: PMC7595506 DOI: 10.4103/jpbs.jpbs_146_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 02/08/2020] [Accepted: 03/02/2020] [Indexed: 11/30/2022] Open
Abstract
Aim: Zirconia-based restoration is successfully replacing metal ceramic restorations in posterior areas. Although higher mechanical properties of zirconia, their use in compromised situation is questionable. Hence, there is a need to modify the design which to strengthen the framework. The aim of this in vitro study was to evaluate the influence of lingual collar design on the flexural strength of CAD/CAM-fabricated posterior three-unit zirconia framework. Materials and Methods: A mandibular metallic stainless steel master mold is designed for a three-unit fixed partial denture framework. All CAD-milled 20 samples are divided into two groups based on the design. Group A––with collar (10 samples) and Group B––without collar (10 samples), tested using universal testing machine to calculate the mean fracture load and flexural strength. Statistical Analysis Used: Descriptive statistics and independent sample t test were used to find the difference between the groups, and simple linear regression was used to find the relationship between load and displacement between the groups. Results: The result of the mean flexural strength for Group A was 11328.06 ± 3770MPa and for Group B was 7633.95 ± 3196MPa; the mean fracture strength observed for Group A was 1274.04 ± 424MPa and for Group B was 858.80 ± 359MPa. A statistically significant difference was observed in flexural strength between Groups A and B (P < 0.05). Conclusion: Zirconia framework with connector dimension of 7 mm2 with lingual collar design can be successfully incorporated in compromised situation where an ideal connector dimension of 9 mm2 cannot be placed.
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Affiliation(s)
- Rajesh Shetty
- Department of Prosthodontics, Yenepoya Dental College, Mangalore, Karnataka, India
| | - Shifa Shoukath
- Department of Prosthodontics, Yenepoya Dental College, Mangalore, Karnataka, India
| | - Naresh H G Shetty
- Department of Prosthodontics, Yenepoya Dental College, Mangalore, Karnataka, India
| | - Sanath K Shetty
- Department of Prosthodontics, Yenepoya Dental College, Mangalore, Karnataka, India
| | - Savita Dandekeri
- Department of Prosthodontics, Yenepoya Dental College, Mangalore, Karnataka, India
| | - Mallikarjuna Ragher
- Department of Prosthodontics, Yenepoya Dental College, Mangalore, Karnataka, India
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Debye K, Tuna T, Bishti S, Wolfart S. Influence of additional reinforcement of fixed long-term temporary restorations on fracture load. J Prosthodont Res 2018; 62:416-421. [PMID: 29636242 DOI: 10.1016/j.jpor.2018.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 02/25/2018] [Accepted: 03/03/2018] [Indexed: 11/29/2022]
Abstract
PURPOSE In implant dentistry, temporary restorations (TR) might often be required for up to one year. The aim of this in vitro study was to evaluate the long-time performance of four-unit TRs in the posterior region based on different materials and reinforcement methods. METHODS One hundred and forty four TRs were manufactured on 16 models simulating an oral situation of two missing posterior teeth. With a computer-aided-design/computer-aided-manufacturing (CAD/CAM) workflow, a TR was fabricated (CAD; Telio CAD), which served as a template for other subgroups. With a vacuum-formed template, unreinforced and reinforced TRs [glass fibres (g; EverStick); polyethylenefibres (p; Ribbond original) and TRs with increased connector area (c; 27.5-35mm2)] were manufactured. Two different composite materials were used (C1: Luxatemp, C2: Protemp). Altogether, 16 subgroups with 8 specimens each were tested. After temporary luting (Temp Bond NE) and artificial-aging [1600 thermo-cycles (5-55°C), 240,000 chewing-cycles (50N)], all specimens were tested until fracture in a universal testing machine. RESULTS After artificial aging, mean fracture loads (N) were: (C1)201.2±109.7, (C1c)1033.0±173.1, (C1p)90.0±40.0, (C1g)75.9±25.9, (C2)108.6±58.6, (C2c)1363.3±148.6, (C2p)104.7±54.7, (C2g)50.0±0.0 and (CAD)232.5±19.1. The one-factor ANOVA analysis showed significant differences for the factors temporary material (p<0.047), reinforcement (p<0.0001) and artificial-aging (p<0.0001). CONCLUSIONS The study indicated that both CAD/CAM TRs and TRs with increased connector areas are suitable for long-term use of one year. No enhancement of fracture load was observed for fibre-reinforced TRs except for the fact that fractured TRs were not totally separated.
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Affiliation(s)
- Katharina Debye
- Department of Operative Dentistry, Periodontology and Preventive Dentistry, RWTH Aachen University, Aachen, Germany.
| | - Taskin Tuna
- Department of Prosthodontics and Biomaterials, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Shaza Bishti
- Department of Prosthodontics and Biomaterials, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Stefan Wolfart
- Department of Prosthodontics and Biomaterials, Medical Faculty, RWTH Aachen University, Aachen, Germany
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Ogino Y, Nomoto S, Sato T. Effect of Connector Design on Fracture Resistance in Zirconia-based Fixed Partial Dentures for Upper Anterior Region. THE BULLETIN OF TOKYO DENTAL COLLEGE 2018; 57:65-74. [PMID: 27320295 DOI: 10.2209/tdcpublication.2015-0034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The purpose of this study was to investigate the influence of the cross-sectional form and area of the connector on fracture resistance in three-unit zirconia fixed partial denture (FPD) frameworks for the upper anterior region. Sixty FPD framework specimens were fabricated using the CAD/CAM system. The cross-sectional form (Type I, II, or III) and area (9.0, 7.0, 5.0, or 3.0 mm(2)) of the connectors differed. The specimens were fixed to a jig capable of applying a load axially to the abutment teeth at an angle of 135 degrees. Each specimen was subjected to fracture load measurements using a universal testing machine and cross-sectional microscopic examination. Fracture load fell significantly with a decrease in cross-sectional area (p <0.01). In terms of cross-sectional form, an isosceles triangle with a gingival base yielded the highest fracture load. These results suggest that the connector of a three-unit zirconia-based FPD framework for the upper anterior region should be triangular, have a gingival base, sufficient height in the loading direction, and a cross-sectional area of >5.0 mm(2).
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Affiliation(s)
- Yasushi Ogino
- Department of Fixed Prosthodontics, Tokyo Dental College
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ADM guidance-ceramics: Fatigue principles and testing. Dent Mater 2017; 33:1192-1204. [DOI: 10.1016/j.dental.2017.09.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/15/2017] [Indexed: 11/19/2022]
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Messias A, Neto MA, Amaro AM, Nicolau P, Roseiro LM. Effect of round curvature of anterior implant-supported zirconia frameworks: finite element analysis and in vitro study using digital image correlation. Comput Methods Biomech Biomed Engin 2017; 20:1236-1248. [DOI: 10.1080/10255842.2017.1348501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Ana Messias
- Department of Dentistry, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CEMMPRE, Center for Mechanical Engineering, Materials and Process, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal
| | - Maria Augusta Neto
- CEMMPRE, Center for Mechanical Engineering, Materials and Process, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal
| | - Ana Martins Amaro
- CEMMPRE, Center for Mechanical Engineering, Materials and Process, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal
| | - Pedro Nicolau
- Department of Dentistry, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CEMMPRE, Center for Mechanical Engineering, Materials and Process, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal
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Calha N, Messias A, Guerra F, Martinho B, Neto MA, Nicolau P. Effect of geometry on deformation of anterior implant-supported zirconia frameworks: An in vitro study using digital image correlation. J Prosthodont Res 2016; 61:139-148. [PMID: 27667555 DOI: 10.1016/j.jpor.2016.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 07/20/2016] [Accepted: 08/27/2016] [Indexed: 10/21/2022]
Abstract
PURPOSE To evaluate the effect of geometry on the displacement and the strain distribution of anterior implant-supported zirconia frameworks under static load using the 3D digital image correlation method. METHODS Two groups (n=5) of 4-unit zirconia frameworks were produced by CAD/CAM for the implant-abutment assembly. Group 1 comprised five straight configuration frameworks and group 2 consisted of five curved configuration frameworks. Specimens were cemented and submitted to static load up to 200N. Displacements were captured with two high-speed photographic cameras and analyzed with video correlation system in three spacial axes U, V, W. Statistical analysis was made using the nonparametric Mann-Whitney test. RESULTS Up to 150N loads, the vertical displacements (V axis) were statistically higher for curved frameworks (-267.83±23.76μm), when compared to the straight frameworks (-120.73±36.17μm) (p=0.008), as well as anterior displacements in the W transformed axis (589.55±64.51μm vs 224.29±50.38μm for the curved and straight frameworks), respectively (p=0.008). The mean von Mises strains over the surface frameworks were statistically higher for the curved frameworks under any load. CONCLUSION Within the limitations of this in vitro study, it is possible to conclude that the geometric configuration influences the deformation of 4-unit anterior frameworks under static load. The higher strain distribution and micro-movements of the curved frameworks reflect less rigidity and increased risk of fractures associated to FPDs.
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Affiliation(s)
- Nuno Calha
- Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal
| | - Ana Messias
- Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal; Centre for Mechanical Engineering, University of Coimbra, Portugal.
| | - Fernando Guerra
- Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal; Centre for Mechanical Engineering, University of Coimbra, Portugal
| | - Beatriz Martinho
- Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal
| | | | - Pedro Nicolau
- Department of Dentistry, Faculty of Medicine, University of Coimbra, Portugal; Centre for Mechanical Engineering, University of Coimbra, Portugal
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Murase T, Nomoto S, Sato T, Shinya A, Koshihara T, Yasuda H. Effect of connector design on fracture resistance in all-ceramic fixed partial dentures for mandibular incisor region. THE BULLETIN OF TOKYO DENTAL COLLEGE 2016; 55:149-55. [PMID: 25212560 DOI: 10.2209/tdcpublication.55.149] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Yttrium tetragonal zirconia polycrystal frameworks were prepared for all-ceramic fixed partial dentures (FPDs) for the mandibular incisor region. The effects of the cross-sectional area and morphology of the connector on its strength were evaluated by fracture tests. Nine types of zirconia framework for a 3-unit FPD for a defect of 1 mandibular central incisor were prepared, each differing in cross-sectional area and morphology. Fracture tests were performed by loading until fracture using a universal testing machine. Fracture load was determined and fracture site examined. Significant differences were observed in fracture load according to the morphology and cross-sectional area of the connector (p<0.05, p<0.01, p<0.001). Fracture load differed significantly among all groups according to cross-sectional area, and was also greater when the shape of the connector formed an isosceles triangle widest at the base and the connector had the same height and width. These values still far exceeded 311 N, however, which is the average occlusal force in the incisor region. The results of this study suggest that connector design affects fracture load.
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Affiliation(s)
- Toshihiko Murase
- Department of Crown and Bridge Prosthodontics, Tokyo Dental College
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Nomoto S, Matsunaga S, Sato T, Yotsuya M, Abe S. Basic Finite Element Analysis of Para-periodontal Ligament in All-ceramic Zirconia Fixed Partial Denture. THE BULLETIN OF TOKYO DENTAL COLLEGE 2015; 56:215-22. [PMID: 26657520 DOI: 10.2209/tdcpublication.56.215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The purpose of the present study was to investigate the validity of incorporating a para-periodontal ligament in the test mold used in a basic fracture test of a zirconia all-ceramic fixed partial denture (FPD). A simplified three-dimensional finite element analysis model was designed based on the three-unit FPD fracture test. Two types of model, one with and one without a para-periodontal ligament between the abutment and base mold, were fabricated. Microfocus CT of the missing first molar area in a dry human mandible was performed. A three-dimensional model was then fabricated based on the data obtained. A load of 600 N was applied to the center of the pontic and stress distribution observed. The model with the para-periodontal ligament showed stress dispersion to the dental root with rotation of the abutment mold. Stress distribution in the finite element analysis model with a para-periodontal ligament showed greater similarity with that in the mandibular model than with that in the other two models without a para-periodontal ligament.
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INAGAKI T, KOMADA W, NEMOTO R, YOSHIDA K, MIURA H. Influence of post and core materials on distortion around 4-unit zirconia bridge margins. Dent Mater J 2014; 33:373-82. [DOI: 10.4012/dmj.2013-306] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Fracture load of milled polymeric fixed dental prostheses as a function of connector cross-sectional areas. J Prosthet Dent 2013; 110:288-95. [DOI: 10.1016/s0022-3913(13)60378-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Alhasanyah A, Vaidyanathan TK, Flinton RJ. Effect of core thickness differences on post-fatigue indentation fracture resistance of veneered zirconia crowns. J Prosthodont 2013; 22:383-90. [PMID: 23387466 DOI: 10.1111/jopr.12016] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2012] [Indexed: 11/30/2022] Open
Abstract
PURPOSE Despite the excellent esthetics of veneered zirconia crowns, the incidence of chipping and fracture of veneer porcelain on zirconia crowns has been recognized to be higher than in metal ceramic crowns. The objective of this investigation was to study the effect of selected variations in core thickness on the post-fatigue fracture resistance of veneer porcelain on zirconia crowns. MATERIALS AND METHODS Zirconia crowns for veneering were prepared with three thickness designs of (a) uniform 0.6-mm thick core (group A), (b) extra-thick 1.7 mm occlusal core support (group B), and (c) uniform 1.2-mm thick core (group C). The copings were virtually designed and milled by the CAD/CAM technique. Metal ceramic copings (group D) with the same design as in group C were used as controls. A sample size of N = 20 was used for each group. The copings were veneered with compatible porcelain and fatigue tested under a sinusoidal loading regimen. Loading was done with a 200 N maximum force amplitude under Hertzian axial loading conditions at the center of the crowns using a spherical tungsten carbide indenter. After 100,000 fatigue cycles, the crowns were axially loaded to fracture and maximum load levels before fracture was recorded. One-way ANOVA (P < 0.05) and post hoc Tukey tests (α = 0.05) were used to determine significant differences between means. RESULTS The mean fracture failure load of group B was not significantly different from that of control group D. In contrast, the mean failure loads of groups A and C were significantly lower than that of control group D. Failure patterns also indicated distinct differences in failure mode distributions. The results suggest that proper occlusal core support improves veneer chipping fracture resistance in zirconia crowns. CONCLUSIONS Extra-thick occlusal core support for porcelain veneer may significantly reduce the veneer chipping and fracture of zirconia crowns. This is suggested as an important consideration in the design of copings for zirconia crowns.
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Affiliation(s)
- Abdulrahman Alhasanyah
- Department of Restorative Dentistry, NJ Dental School, University of Medicine and Dentistry of NJ, Newark, NJ 07103, USA
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