1. Do resin cement viscosity and ceramic surface etching influence the fatigue performance of bonded lithium disilicate glass-ceramic crowns?
- Author
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Kiara Serafini Dapieve, Gabriel Kalil Rocha Pereira, Andressa Borin Venturini, Natália Daudt, André Valcanaia, Marco Cícero Bottino, and Luiz Felipe Valandro
- Subjects
Dental Stress Analysis ,Ceramics ,Crowns ,Surface Properties ,Viscosity ,Dental Bonding ,Dental Porcelain ,Hydrofluoric Acid ,Resin Cements ,Cross-Sectional Studies ,Mechanics of Materials ,Materials Testing ,General Materials Science ,General Dentistry - Abstract
To assess the effects of a resin cement in high and low viscosity and distinct conditioning of the intaglio surface of lithium disilicate glass-ceramic crowns on fatigue performance of the crowns.Prosthetic preparations (full-crown) in resin epoxy and crowns in lithium disilicate glass-ceramic were machined and allocated considering 2 factors (n = 10): "surface treatment" (HF - 5% hydrofluoric acid etching, followed by silane application; or EP-self-etching ceramic primer) and "resin cement" (high or low viscosity). The preparations were etched with 10% hydrofluoric acid and an adhesive was applied. The intaglio surfaces of the ceramic crowns were treated as aforementioned (HF or EP) and luted with high or low viscosity. The bonded sets were subjected to fatigue testing (step-stress approach: initial load of 200 N, step-size of 50 N, 10,000 cycles/step, 20 Hz) and complementary analyses (fractographic, topographic, and cross-sectional bonded interfacial zone analyses) were performed.Treatment with HF and silane with high viscosity resin cement (955 N/156,000 cycles) and EP with low viscosity resin cement (1090 N/183,000 cycles) showed the best fatigue performance (statistical similarity between them). The failures originated from defects of the cement-ceramic interface, and the HF treatment induced a more pronounced topographical alteration.Distinct topographical patterns from the HF and EP treatments induced better fatigue results for the specific viscosity of the resin cement. Therefore, the fatigue performance depended on the existing topography, type of intaglio surface's defects/irregularities after surface treatment, and how the luting agent filled the irregularities.
- Published
- 2022