Objective: To investigate the influence of translucency of CAD/CAM ceramic milling blocks on the final color of porcelain veneer cemented using resin cement with two different opacities.
Materials and methods: A standardized incisal lap preparation was made on a maxillary right central incisor that was duplicated using composite resin material (Z250, A4, 3M ESPE). The resin dies were individually laser scanned (Bluecam, Sirona) in order to build a 3D model of the porcelain veneer on the CAD software (Cerec 3D). Three types of milling blocks were used to fabricate the required restorations: multichromatic, high translucency, and low translucency milling blocks (IPS Empress CAD, A1 Vita shade tab). The milled veneers were polished, glazed, and bonded on the resin dies using high opacity and low opacity resin cements (Panavia F2.0). A digital shade guide device (Easyshade Advance, Vita) was used to measure color parameters (CIE Lab values) at the incisal, middle, and cervical third of each cemented restoration. ΔE values of the cemented veneers were calculated against the target color (A1).
Results: Cementation of porcelain veneers resulted in significant color change of the resin die (A4) as ΔE values ranged between 8.9 and 13.7. However, the type of milling block did not have an observable effect on final color as the measured ΔE values, against original die color, were very close for the multichromatic block (ΔE = 10.7 ± 0.1), high translucency (ΔE = 9.7 ± 0.09), and low translucency blocks (ΔE = 13.4 ± 0.11). The opacity of the used resin cement did not affect the final shade match, as the observed ΔE values using either high opacity and low opacity resin cement were less than 2 for the three used ceramic blocks. The greatest color difference was observed between the incisal third of multichromatic veneers (ΔE = 8.9) and the cervical third of low translucency veneers (ΔE = 13.7), while for the rest of the test groups this shift was not clinically observable (ΔE < 2.5).
Conclusion: Within the limitations of this study, the shade match of CAD/CAM porcelain veneers was not influenced by the translucency of used milling block or the opacity of the resin cement.