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Velho HC, Dapieve KS, Grassi EDA, Borges ALS, de Melo Marinho RM, Pereira GKR, Venturini AB, Valandro LF. Fatigue behavior, failure mode, and stress distribution of occlusal veneers: influence of the prosthetic preparation cusp inclinations and the type of restorative material. Clin Oral Investig 2023; 27:5539-5548. [PMID: 37490118 DOI: 10.1007/s00784-023-05173-1] [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: 05/21/2023] [Accepted: 07/13/2023] [Indexed: 07/26/2023]
Abstract
OBJECTIVE To evaluate the effects of cusp inclination of the prosthetic preparation's occlusal surface and type of restorative material on the fatigue behavior, failure mode, and stress distribution of occlusal veneers. MATERIALS AND METHODS Glass fiber-reinforced epoxy resin prosthetic preparations for occlusal veneers with three different occlusal surface cusp inclination degrees (0°, 15°, and 30°) were produced and assigned into six testing groups (n = 11) according to the cusp inclination (0°, 15°, or 30°) and type of restorative material (lithium disilicate-LD or resin composite-RC). Despite different substrate preparation cusp inclination degrees, the restorations were designed maintaining 30° inclination between the cusps at the occlusal surface and a thickness of 0.7 mm at the central groove region of the restorations to be machined in a CAD/CAM system. After cementation, the specimens were stored for about 7 days (under water at 37 °C), and subsequently submitted to a load to failure test (n = 2) and an intermittent cyclic fatigue test (n = 9) (initial load: 100 N; step size: 50 N; cycles/step: 10,000; loading frequency: 20 Hz; loading piston: 6-mm-diameter stainless steel) until observing cracks. The data were analyzed by two-way ANOVA, Kaplan-Meier, and Mantel-Cox post hoc tests. Finite element analysis (FEA) and fractographic analyses were performed. RESULTS The fatigue performance of LD and RC occlusal veneers was evaluated based on different prosthetic preparation cusp inclinations. The 0° inclination showed the best fatigue performance for both materials (LD: 944N, RC: 861N), while the 15° and 30° inclinations had lower values (LD: 800N and 533N, RC: 739N and 717N, respectively). The study also found that for a 0° inclination, LD occlusal veneers performed better than RC ones (LD: 944 N > RC: 861N), while for a 30° inclination, RC occlusal veneers had better fatigue performance than LD ones (LD: 533N < RC: 717N). No significant difference was observed between the materials for a 15° inclination (LD: 800N = RC: 739N). The FEA results showed a higher tensile stress concentration on lithium disilicate than on resin composite occlusal veneers. All lithium disilicate occlusal veneers showed radial crack failures, while resin composite occlusal veneers showed Hertzian cone cracks and radial cracks combined. CONCLUSION Considering mechanical perspective only, RC occlusal veneers should be indicated when prosthetic preparation cusps inclinations are 30°. When 0° prosthetic preparation cusps inclinations are observed, LD occlusal veneers will behave mechanically better. When a 15° cusp inclination is preserved, both restorative materials behave similarly.
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Affiliation(s)
- Helder Callegaro Velho
- Post-Graduate Program in Oral Science, Prosthodontics-Biomaterials Unit, School of Dentistry, Center for Development of Advanced Materials, Federal University of Santa Maria, UFSM Campus, 1000 Roraima Av., T Street, Building 26H, Santa Maria, Rio Grande Do Sul, 97105-900, Brazil
| | - Kiara Serafini Dapieve
- Post-Graduate Program in Oral Science, Prosthodontics-Biomaterials Unit, School of Dentistry, Center for Development of Advanced Materials, Federal University of Santa Maria, UFSM Campus, 1000 Roraima Av., T Street, Building 26H, Santa Maria, Rio Grande Do Sul, 97105-900, Brazil
| | - Elisa Donária Aboucauch Grassi
- Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), 777, Engenheiro Francisco José Longo Av, São José Dos Campos, São Paulo, 12245-000, Brazil
| | - Alexandre Luiz Souto Borges
- Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), 777, Engenheiro Francisco José Longo Av, São José Dos Campos, São Paulo, 12245-000, Brazil
| | - Renata Marques de Melo Marinho
- Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), 777, Engenheiro Francisco José Longo Av, São José Dos Campos, São Paulo, 12245-000, Brazil
| | - Gabriel Kalil Rocha Pereira
- Post-Graduate Program in Oral Science, Prosthodontics-Biomaterials Unit, School of Dentistry, Center for Development of Advanced Materials, Federal University of Santa Maria, UFSM Campus, 1000 Roraima Av., T Street, Building 26H, Santa Maria, Rio Grande Do Sul, 97105-900, Brazil
| | - Andressa Borin Venturini
- Post-Graduate Program in Oral Science, Prosthodontics-Biomaterials Unit, School of Dentistry, Center for Development of Advanced Materials, Federal University of Santa Maria, UFSM Campus, 1000 Roraima Av., T Street, Building 26H, Santa Maria, Rio Grande Do Sul, 97105-900, Brazil
| | - Luiz Felipe Valandro
- Post-Graduate Program in Oral Science, Prosthodontics-Biomaterials Unit, School of Dentistry, Center for Development of Advanced Materials, Federal University of Santa Maria, UFSM Campus, 1000 Roraima Av., T Street, Building 26H, Santa Maria, Rio Grande Do Sul, 97105-900, Brazil.
- Prosthodontics-Biomaterials Unit, Faculty of Odontology, Federal University of Santa Maria, UFSM Campus, 1000 Roraima Av., T Street, Building 26F, Room 2386, Santa Maria, Rio Grande Do Sul, 97105-900, Brazil.
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Borges ALS, Tribst JPM, de Lima AL, Dal Piva AMDO, Özcan M. Effect of occlusal anatomy of CAD/CAM feldspathic posterior crowns in the stress concentration and fracture load. Clin Exp Dent Res 2021; 7:1190-1196. [PMID: 34240808 PMCID: PMC8638277 DOI: 10.1002/cre2.454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 04/21/2021] [Accepted: 05/05/2021] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVES This study evaluated the effect of restoration occlusal design on the maximum fracture load and stress distribution of a feldspathic ceramic crown. MATERIALS AND METHODS Twenty dentin analogues were used to simulate a full-crown preparation. Next, 20 feldspathic crowns were milled according to the occlusal design parameter available in the CAD database (Young or Adult). The crowns were cemented with dual cure resin-cement and loaded until fracture at 1 mm/min crosshead speed. Data were analyzed by using one-way ANOVA and Tukey tests (p < 0.05). The same geometry and experimental setup was modeled and exported to the computer aided engineering software and tensile stress concentration was calculated using the finite element method with 300 N occlusal load simulation. RESULTS The occlusal anatomy significantly influenced the load-to-fracture (p < 0.05). Adult design showed higher mean values (1149 ± 201 N) than Young design (454 ± 77 N). The maximum principal stress criteria showed similar stress pattern for both designs, however, the highest stress concentration was calculated for Young design (91 MPa) in the occlusal surface. CONCLUSIONS An anatomy design with reduced cusp angulation and less evident occlusal sulcus can reduce the stress concentration and increase the fracture load for feldspathic CAD/CAM posterior crowns.
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Affiliation(s)
- Alexandre Luiz Souto Borges
- Department of Dental Materials and ProstheticsSão Paulo State University (UNESP), Institute of Science and TechnologySão José dos CamposBrazil
| | - João Paulo Mendes Tribst
- Department of Dental Materials and ProstheticsSão Paulo State University (UNESP), Institute of Science and TechnologySão José dos CamposBrazil
| | - Aline Lins de Lima
- Department of Dental Materials and ProstheticsSão Paulo State University (UNESP), Institute of Science and TechnologySão José dos CamposBrazil
| | - Amanda Maria de Oliveira Dal Piva
- Department of Dental Materials and ProstheticsSão Paulo State University (UNESP), Institute of Science and TechnologySão José dos CamposBrazil
| | - Mutlu Özcan
- Division of Dental Biomaterials, Center for Dental and Oral Medicine, Clinic for Reconstructive DentistryUniversity of ZurichZürichSwitzerland
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