Effect of thermomechanical aging on the surface roughness and color stability of novel CAD-CAM materials: An in-vitro study

Abstract

Objective:. This in-vitro study aimed to evaluate the surface roughness (Ra) and color stability of novel monolithic CAD-CAM materials after thermomechanical aging. 
 Methods: Forty specimens were obtained from 4 different materials (a resilient ceramic (C), ceramic-reinforced PEEK (BH), lithium disilicate glass ceramic (EX), and a resin based composites (B) (n=10). Initial Ra and color coordinates were recorded. All specimens were than subjected to thermomechanical aging. Ra and color coordinate measurements were repeated. CIEDE2000 formula was used to calculate the color changes (ΔE00). Kruskal-Wallis and Dunn tests were used to analyze data, while the effect of aging on Ra was analyzed with Wilcoxon test (α=.05). 
 Results: Regardless of aging, BH showed higher Ra than EX (P.05). Ra of ceramic-reinforced PEEK was above clinical threshold, regardless of thermomechanical aging. 
 Conclusion: Thermomechanical aging caused a color change that was perceptible for all the materials tested, while it was also unacceptable for ceramic-reinforced PEEK.