The aim of this study was to conduct an comprehensive comparative laboratory evaluation of the stain resistance of a Russian CAD/CAM block made from Nolatek composite material compared to widely used foreign counterparts – Tetric CAD and a composite material manufactured by 3M ESPE – Paradigm MZ100 which are traditionally used in the fabrication of aesthetically significant prosthetic restorations. The aesthetic stability of restorative materials is a key factor determining the longevity, clinical efficacy, and predictability of prosthetic treatment, particularly in the smile zone, where even minor color changes can be visually noticeable and negatively perceived by patients. Discoloration of restorations due to pigmenting agents of dietary origin, such as coffee, tea, red wine, and colored beverages, can significantly impair the appearance of prosthetic restorations, reduce patient satisfaction with treatment results, and lead to the need for premature correction or replacement of restorations. Therefore, assessing the color stability of CAD/CAM composites is of significant scientific and practical interest. The laboratory study was conducted using standard samples of the CAD/CAM composites under study, which were subjected to controlled exposure to the most common food colorings, simulating the conditions under which the materials are used in the oral cavity. Color change was assessed using spectrophotometric analysis and the calculation of the color difference index ΔE*, the obtained values of which were compared with clinically acceptable color change thresholds. Statistical data processing was performed using descriptive statistics. The study results showed that all three CAD/CAM composites studied demonstrated satisfactory stain resistance under laboratory experimental conditions. The color change indicators of the Russian-made Nolatek material were comparable to those of Tetric CAD and Paradigm MZ100 materials, with no statistically significant differences. Thus, the obtained data demonstrate the high color stability of the Nolatek composite material and confirm its suitability as a competitive alternative to foreign CAD/CAM materials.
Vafin et al. (Sun,) studied this question.