Influence of gingival color on the color differences of dental laminate veneers

Abstract

Statement of problem

The effect of various gingival colors on the color differences of laminate veneers is unclear and comparative evaluations should be documented.

Purpose

The purpose of this in vitro study was to investigate the influence of different gingival colors on the color differences of laminate veneers.

Material and methods

Five maxillary typodonts were used to obtain study models using 5 different gingival colors: light pink (LP), dark pink (DP), orange (Or), brown (Br), and violet (V). A total of 45 laminate veneers were milled using A1-shaded lithium disilicate ceramic and cemented on natural tooth-colored substrates. Color parameters were assessed using a spectroradiometer at 3 measurement areas (cervical third, mid-third, and incisal third) along the midline of laminate veneer with a focus measuring diameter of 1 mm. Color differences (∆E*_ab and ∆E₀₀) were calculated and compared with perceptibility (PT: ∆E*_ab=1.22, ΔE₀₀=0.81) and acceptability (AT: ∆E*_ab=2.66, ΔE₀₀=1.77) visual thresholds. Color variation data were statistically analyzed using 2-way ANOVA and Tukey HSD tests (α=.05).

Results

Two-way ANOVA results of the ∆E*_ab values revealed significant interaction between the gingival color and the measurement area (P=.002). The ∆E*_ab and ΔE₀₀ values of laminate veneers were significantly higher in the LP-V group that presented values above AT (P<.001). Measurement area significantly influenced ∆E values of laminate veneers (P<.001). Greater ∆E values were registered at the measurement area of the cervical third in the groups of LP-DP, LP-Br, LP-V, and Or-V. Regardless of the measurement area, ∆E₀₀ values below AT were obtained for the gingival color groups of LP-Or, DP-Or, DP-Br, and DP-V.

Conclusions

Gingival color influenced the color differences of laminate veneers. When the gingival color was a darker gingival color, rather than light pink, the color difference increased, especially at the measurement area of the cervical third.