Resin cement coating reverts the machining damage on the flexural fatigue strength of lithium disilicate glass ‐ceramic

This study evaluated the effect of resin cement coating with high and low viscosities on the flexural fatigue strength of machined lithium disilicate glass-ceramic. Discs (IPS e.max CAD; Ivoclar Vivadent) were prepared and divided according to the surface condition (machining [M] —CEREC inLab; and polishing [P]—laboratory procedures), resin cement coating (with or without), and cement viscosity (high [H] and low [L]). The ceramic bonding surface was etched/primed by a one-step primer application followed by resin cement application (Variolink N base + high or low vis cosity catalyst; Ivoclar Vivadent). Biaxial flexural fatigue strength was evaluated on a piston-on-three-ball set by the step-test method (n = 15) (initial stress: 60 MPa; incremental steps: 20 MPa; 10,000 cycles/step, at 20 Hz). Weibull statistics were used for fatigue data. Contact angle, topographic, and fractographic analysis were also performed. Machining produced statistically lower contact angle than polishing and a sig nificant detrimental effect on the fatigue behavior (σ0M  = 247.2 [246.9–268.3];σ0P  = 337.4 [297.8–382.4]). Machined groups followed by resin cement coating (σ0MH  = 297.9 [276.0–321.5];σ0Ml  = 301.2 [277.1–327.4]) behaved similarly to the polished and coated groups (σ0PH  = 342.0 [308.9–378.5];σ0PL  = 357.3 [324.7–393.1]), irrespective of the cement viscosity. Therefore, cement coating has able to revert the detrimental effects of the machin...
Source: Journal of Biomedical Materials Research Part B: Applied Biomaterials - Category: Materials Science Authors: Tags: RESEARCH ARTICLE Source Type: research