Effect of Accelerated Aging on The Color Stability and Bond Strength of Two Types of Glass-based Ceramics: An In-vitro Study

Objective: The objective of the present study was to investigate the effect of accelerated aging on the color stability and bond strength of two types of glass-based ceramics. Materials and methods: A total of 42 disk-shaped specimens were fabricated from two ceramic materials; IPS e.max CAD and Vita Suprinity; 21 for each ceramic material, with dimensions of 14 mm length×12 mm width ×1mm thickness were obtained and crystalized according to the manufacture instructions. They were then divided randomly into 2 groups: the first group was 14 discs, 7 from each ceramic material for the initial color measurement using a spectrophotometer. The second group consisted of 28 disc-shaped specimens, 14 for each ceramic material, cemented to their corresponding composite resin disk under static load using dual-cured resin cement. Shear bond strength test for 7specimens from each group was done by compressive load applied at composite-ceramic interface using the universal testing machine traveling at cross-head speed of 0.5 mm/min. The failure load was recorded in Newton. The aging process was done by the use of special weathering machine called Environmental Incubator Model. The discs that were artificially aged underwent the same color and bond strength measurements as before the artificial aging process.  Results: Artificial accelerated aging had a statistically significant effect on the color stability of tested groups. Vita Suprinity recorded higher color difference (∆E) mean value (2.52 ± 0.63) than E.max group (1.61±0.48). There was no statistically significant difference in the shear bond strength test of two ceramic materials. Conclusions: Both ceramic materials performance was clinically acceptable regarding their color stability. E.max CAD showed significant better color stability than Vita Suprinity. Both ceramic materials had similar bond strength values.