The evaluation of the color stability of CAD / CAM ceramics after different finishing procedures and thermal aging

CAD / CAM systems, which are designed and manufactured in a single appointment, are used frequently in today's dentistry. It is important to imitate the optical properties of natural teeth with laminate veneers, which offers an aesthetic and conservative alternative to full crowns. The preservation of the final color of the restorations is important for patients and clinicians. The aim of this study is to compare the effects on color of different surface treatments applied to 3 different full ceramics after thermal aging. 216 samples were prepared from 3 different ceramic material (LAVA Ultimate-LU, IPS e.max CAD-EC, VITA Suprinity-VS) in A1 HT color with dimensions of 0.5 x 0.05 mm thickness and 14x12 mm in size. Color measurements of the samples were performed in spectrophotometer instrument using CIE Lab color system after 4 stages (initial color, post-polishing, post-cementation and after artificial aging. The results were evaluated by using variance analysis and Fisher LSD test. Resin nano ceramics (LU) showed higher color change values than zirconium-reinforced lithium silicate (VS) and lithium disilicate (EC) ceramics after thermal aging. For LU and VS, manual polish and glaze showed similar color change values (p>0.05). In the EC group, glaze treatment was statistically different from the manual and control group (p<0.05). Among the ceramic groups, the color change values of zirconium-reinforced lithium silicate (VS) and the glaze-treated subgroup of lithium disilicate (EC) samples were below the clinically acceptable level (∆E<3.5). Vita Suprinity showed the lowest color change for all stages. In terms of color stability, glaze for EC, manual polish as an alternative to glaze treatment for LU and VS can be proposed. Key Words: CAD/CAM, full ceramics, surface finishing procedures, color stability