The Thickness and Opacity of Aesthetic Materials Influence the Restoration of Discolored Teeth.

OBJECTIVES: This study aimed to evaluate the influence of thickness and opacity on the ability of composite resin and ceramic veneer restorations to mask discolored teeth.
METHODS: Ninety veneers were made of lithium disilicate ceramic, shades BL1 and 0 (IPS e.max Press, Ivoclar Vivadent), and 60 were made of composite resin, shade BL-L (IPS Empress Direct, Ivoclar Vivadent). The veneers measured 4 mm in width x 4 mm in length and had a thickness of 0.7, 1.0, or 1.2 mm. One hundred and fifty human premolars were selected to obtain 150 dental fragments with the following dimensions: 4 mm x 4 mm x 3 mm (width x length x thickness). The fragments were discolored, submitted to color measurement and randomly assigned to 15 groups (n=10) according to the type and opacity of the restorative material (IPS e.max Press: high translucency [HT], low translucency [LT], and medium opacity [MO]; IPS Empress Direct: dentin and enamel) and thickness of the veneers (0.7, 1.0, and 1.2 mm). After cementation of the ceramic or composite resin veneers using a translucent resin cement (RelyX veneer, 3M), a final color measurement was taken from each specimen and the total color variation (ΔE) was calculated by subtracting the initial and the final color measurement. The final lightness (L*) of the restored dental fragments was also calculated.
RESULTS: The highest ΔE values were observed for the LT and MO ceramic groups, followed by dentin composite resin. Regarding the different thicknesses of ceramic veneers, every 1.2-mm-thick group had higher values of ΔE, considering their respective opacities (p<0.05). The highest lightness values were found for the LT and MO ceramic veneers (thickness of 1.2 mm). Dentin-shade composite resins showed similar lightness values in all groups.
CONCLUSION: The best thickness/opacity combinations for masking discolored dental substrates were LT and MO ceramic veneers with 1.2-mm thickness. Dentin-shade composite resin veneers with a thickness of 0.7-1.0 mm showed good ability to mask discolored dental substrates. ©Operative Dentistry, 2021.