Evaluation of Color Stability and Surface Properties of Different CAD/CAM Materials: An In vitro Study

The widespread use of CAD/CAM technologies in dentistry has enabled the application of various restorative materials with differing mechanical and aesthetic characteristics. While lithium disilicate ceramics are known for their strength and translucency, resin-matrix ceramics are preferred for their ease of processing and intraoral repairability. However, their long-term color stability and surface behavior under staining conditions remain insufficiently understood.

This study aimed to evaluate and compare the effects of different staining solutions on the color stability, surface roughness, microhardness, and contact angle of selected CAD/CAM restorative materials.

An in vitro study was conducted using three resin-matrix ceramics and one fully crystallized lithium disilicate ceramic. Specimens were immersed in three different staining solutions (distilled water, coffee, and red wine). Measurements of color change (ΔE00), surface roughness (Ra), microhardness, and contact angle were performed at baseline and after 30 days.

All materials showed varying levels of discoloration, with the highest ΔE00 value observed in the Shofu Block HC group stored in red wine (ΔE00 = 5.48 ± 0.43). Lithium disilicate ceramic exhibited the least discoloration among all tested materials. In coffee and red wine, all materials, including lithium disilicate, exceeded the clinically acceptable threshold (ΔE00 = 1.8) after 30 days, although lithium disilicate consistently exhibited lower discoloration compared to resin-matrix ceramics. Surface roughness increased in all groups but remained within clinically acceptable limits. Contact angle values varied according to material type, reflecting differences in surface wettability.

Resin-matrix ceramics demonstrated greater susceptibility to discoloration and surface changes than lithium disilicate ceramic. Although lithium disilicate exhibited the lowest discoloration among the tested materials, its ΔE00 values also exceeded the clinical acceptability threshold (ΔE00 = 1.8) after 30 days of immersion in coffee and red wine. These findings indicate that material composition and environmental exposure conditions play a critical role in determining the long-term aesthetic and surface performance of CAD/CAM restorations.