In vitro comparison of the color degradation of two computer-aided design/computer-aided manufacturing provisional materials: A 12-month simulation

Abstract

Aim: This study evaluated the color aging of two computer aided design/computer aided manufacturing (CAD/CAM) provisional materials of different compositions (polymethyl methacrylate and composite resin) after exposure to thermal aging and immersion in coffee for 3, 6, and 12 intraoral months. Setting and Design: The current in vitro study was conducted from September to December 2021 at the Craniofacial laboratory at the Saint Joseph University in Beirut, Lebanon. Materials and Methods: The shades of 2.0 mm thick, 10.0 mm in diameter disk shaped specimens of VITA CAD Temp ® and Ceramill ® TEMP were measured using the VITA Linearguide 3D MASTER ® and a conversion table to extract the CIE L*a*b* values on a white background ( n = 30). Statistical Analysis Used: The color differences ΔE at 3, 6, and 12 months were calculated and analyzed by repeated measures ANOVA followed by Bonferroni multiple comparisons, univariate analyses, and one sample t tests. Results: The mean ΔE T1/T0 , ΔE T2/T0 , and ΔE T3/T0 values were significantly higher than the cutoff values for acceptability and perceptibility for the VITA CAD Temp ® and the Ceramill ® TEMP groups. In addition, the increase in ΔE overtime was significantly greater in the Ceramill ® TEMP group compared to the VITA CAD Temp ® group. Conclusions: The Ceramill ® TEMP changed color more and faster than the VITA CAD Temp ® . In addition, whether at 3, 6, or 12 months, the color variations of both materials are not only perceptible but also unacceptable compared to the initial shade.

Effect of milling procedures in CAD-CAM systems on the color changes of CAD-CAM polymethyl methacrylate resin material as interim material

“…After prolonged use, a variety of factors can influence the color change of denture materials. These factors has been widely studied [ 13 – 20 ], however the effects of tungsten carbide bur quality on the color changes of CAD-CAM PMMA resins have not been investigated. For this reason, the aim of the current study was to assess the impact of new and used burs on the color changes of CAD-CAM PMMA resin after and before thermocycling.…”