Impact of Bleaching before or after Veneer Preparation on Color Masking Ability of Laminate Veneers: An In Vitro Study

Abstract

Purpose. This study evaluates the effect of bleaching before or after veneer preparation and the depth of preparation on color masking ability of laminate veneers. Methods. Sixty extracted premolars were artificially stained to vita shade A4, verified by digital spectrophotometer (Vita Easy Shade V), and then divided into three groups: NB = nonbleached , BBP = bleaching before preparation, and BAP = bleaching after preparation. Based on the preparation depths, each group was further divided into two subgroups: S 1 = 0.5 mm and S 2 = 1.0 mm . BBP and BAP were subjected to one session of in-office bleaching using 35% hydrogen peroxide. IPS e-max CAD veneers of 0.5 and 1.0 mm thickness (corresponding to the preparation depths) of the same shade and translucency (HT A1) were cemented immediately to the bleached surfaces. Immediately after cementation, the color change Δ E between the baseline (after staining) and the resulted shades was measured using the Vita Easy Shade V digital spectrophotometer and CIELab color system. Results. Bleached groups exhibited a significant Δ E value compared to the nonbleached group ( p < 0.05 ). BAP showed the highest Δ E value. No significant difference was found between BBP and BAP. S2 revealed a significant Δ E value than S1 ( p < 0.05 ). No significant difference was found between S1of BAP and S2 of NB, BBP, and BAP ( p > 0.05 ). Regarding the color coordinates, the difference between the tested groups was highly significant in lightness ( Δ L ∗ ) ( p < 0.001 ), while no significant differences were found in green/red value ( Δ a ∗ ) and yellow/blue value ( Δ b ∗ ) ( p > 0.05 ). Conclusions. In cases of severe tooth discoloration, one session of in-office bleaching before or after veneer preparation and the preparation depth do not influence the color masking ability of laminate veneers.

Digital image analysis of fluorescence of ceramic veneers with different ceramic materials and resin cements

“…Since the results obtained in vitro experiments are not completely realistic, for it cannot completely simulate the complex oral environment. In clinical practice, the amount of tooth tissue removed is always based on clinical treatment needs 39) . The prosthetics are prepared according to abutment morphology, with irregular curvature and thickness.…”

Quantitative Measurements of the Depth of Enamel Demineralization before and after Bleach: An In Vitro Study

“…Bleaching is a viable alternative treatment to attempt aesthetic improvement of discolored teeth. Depending on the type and the severity of tooth discoloration, the tooth can be treated by bleaching, veneering, or a combination of both [ 37 ].…”