Color Stability of CAD/CAM versus Conventionally Processed Denture Base Resins: A Systematic Review

This systematic review aimed to gather conclusive information from existing research that compared the color stability between conventional and CAD/CAM-processed denture resins. The Web of Science, MEDLINE-PubMed, and Scopus electronic databases were searched to identify the relevant, original, peer-reviewed clinical and in vitro studies and experimental reports published in English. A thorough analysis revealed seven publications fulfilling the inclusion criteria. In the included studies, the denture resins color stability was evaluated following thermal cycling, exposure to staining media, mechanical brushing, and immersion in denture cleansers. Color measurements were performed using the International Organization for Standardization recommended CIE76 (Delta E * ab) formula in five studies and the CIEDE2000 (Delta E00) formula in two studies. Most studies compared compression-molded acrylic resins with CAD/CAM-milled resins followed by CAD/CAM 3D printed resins. The overall color change values in these studies ranged between 0.48 and 23.66. The CAD/CAM-printed and compression-molded resin specimens demonstrated the lowest (1.41) and highest (4.51) mean color change values, respectively. The injection-molded and CAD/CAM-milled specimens showed color change values of 1.8 and 3.78, respectively. Based on the existing literature comparing the conventional and digitally processed denture resins color stability, it is concluded that the latter yield better color stability than the former. However, the specific data regarding the color stability of denture resins fabricated by the two CAD/CAM processing methods and the two conventional methods remain inconclusive.