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RESEARCH PRODUCT

Long-term fracture load of all-ceramic crowns: Effects of veneering ceramic thickness, application techniques, and cooling protocol

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Made available in DSpace on 2021-06-25T10:46:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-11-01 Background: To evaluate, in vitro, the effects of the cooling protocol, application technique, and veneering ceramic thickness on the fracture resistance of ceramic crowns with Y-TZP frameworks. Material and Methods: 80 frameworks were made from zirconia by the CAD/CAM technique and divided into 8 groups (n = 10) according to the factors: “application technique” (stratified-L and pressed -P), “thickness” (1 mm and 2 mm), and “cooling protocol” (slow-S and fast-F) of the feldspathic veneering ceramic. After, all crowns were cemented over G10 preparations with resin cement (Panavia F, Kuraray), mechanically cycled (2×106 cycles, 200 N, 3Hz), and subjected to the axial compression resistance test (0.5 mm/min, 10 kN). The data (N) underwent descriptive statistical analysis by 3-way ANOVA and Tukey's test (5%). Fracture analysis was performed to determine the possible origin of failure. Results: The factors “cooling protocol” (P=0.0058) and “application” technique (P=0.0001) influenced the fracture resistance of the crowns. For pressed veneer technique, the P2S (4608.9±464.5). A presented significantly higher results than that P2F(3621.1±523.0)BCD (Tukey's test). For the stratified technique, this difference was not observed (P>0.05). The thickness of the veneering ceramic was not significant regardless of the cooling protocol and technique (P>0.05). The predominant failure mode was chipping of the ceramic veneer originating in the subsurface. Conclusions: The pressed technique, used with a slow-cooling protocol, leads to the best outcome for the veneering of all-ceramic crowns. University Hospital Lauro Wanderley Federal University of Paraíba (UFPB) Department of Dental Materials and Prosthodontics São Paulo State University (Unesp) Institute of Science and Technology, São José dos Campos Department of Dentistry Santo Amaro University Department of Dentistry Division of Prosthodontics Federal University of Rio Grande do Norte (UFRN) Department of Dental Materials and Prosthodontics São Paulo State University (Unesp) Institute of Science and Technology, São José dos Campos