Effect of CAD-CAM ceramic materials on the color match of veneer restorations

Statement of problem. With the different translucency levels and types of computer-aided design and computer-aided manufacturing (CAD-CAM) ceramic materials, choosing the most appropriate CAD-CAM ceramic materials to better reproduce the color appearance of natural teeth can be challenging. Purpose. The purpose of this in vitro study was to analyze the color differences between natural teeth and milled veneers fabricated with the different types of CAD-CAM ceramic materials. Material and methods. Ten extracted maxillary central incisor teeth with the A2 shade in the body region were prepared for ceramic veneers. The veneer restorations were designed by using the duplicating method and fabricated from 9 milling blocks (IPS e.max CAD HT/LT, Lava Ultimate CAD HT/LT, VITA SUPRINITY HT/T, IPS Empress CAD HT/LT/Multi) in a dental milling unit (n=10). The bonding surface of the abutment tooth was coated with a thin layer of a separating agent, and the veneer specimen with resin cement was then bonded to the corresponding abutment tooth. A clinical spectrophotometer was used to measure the Commission Internationale de l'Eclairage Lab values of natural teeth, abutment teeth, and milled veneers in the cervical, body, and incisal regions. Color differences between the natural tooth and A2 shade tab (Delta E-1) and between the milled veneer and natural tooth (Delta E-2) were calculated. The Delta E-2 values were compared with the perceptibility threshold (Delta E=2.6) and acceptability threshold (Delta E=5.5). The paired-samples t test, 1-way analysis of covariance, and 2-way ANOVA were used to analyze data (alpha=.05). Results. The results of 1-way analysis of covariance showed that ceramic materials significantly affected the a* and b* values of the milled veneers (P<.001) but did not affect the L* values of the milled veneers (P>.05). The results of 2-way ANOVA indicated that the Delta E-2 values were not significantly affected by different CAD-CAM ceramic materials (F=1.560, P=.138), while statistically significant differences were found in the veneer regions (F=6.588, P=.002). The Delta E-2 values ranged from 2.41 to 5.36, less than the clinically acceptable color threshold of 5.5. Conclusions. The color parameters of milled veneers were affected by the different types of CADCAM ceramic materials. The color of the veneer restoration was able to match that of the natural tooth.

Automated summary

The study aimed to analyze the color differences between milled veneers fabricated with different CAD-CAM ceramic materials and natural teeth. Results showed significant effects of different ceramic materials on the hue of milled veneers, but not on the lightness values; the color of the milled veneer was able to match that of the natural tooth.