Thermal-cycling, simulated brushing, and beverages induced color changes and roughness of CAD/CAM poly (methyl methacrylate) denture resins

The aim of the present study was to evaluate and compare the effect of thermal-cycling, mechanical brushing and beverage storage on the colour changes and surface roughness of conventional heat-polymerized and CAD/CAM PMMA used to fabricate complete dentures. A total of 100 specimens measuring 10 mm in diameter and 3 mm in thickness were fabricated from conventional PMMA resin (Heat-cured, Major. Base.20, Moncalieri, Italy) and CAD/CAM blocks (Opera system, Principauté de Monaco, French). The specimens were subjected to a combined surface treatment involving thermo-cycling, mechanical brushing, and immersed in either artificial saliva (AS), coffee, tea, Coca-Cola, or lemon juice. Colour differences (ΔE) and surface roughness (Ra) was determined using a spectrophotometer and non-contact profilometer, respectively. The data were analyzed using IBM SPSS v.20 ( α = 0.05). Factorial ANOVA showed that independent factors, namely material, beverages, and the interaction between independent factors, significantly influenced ΔE (F = 76.862; p