The effectiveness of opaquer and color-modifier materials: a laboratory study

Masking Ability of the Combined Application of Opaquers and Resin Composite on Discolored Backgrounds

The aim of this study was to evaluate the masking ability of a combined application of opaquers and resin composite over discolored backgrounds: A3, A3.5, C2, C3, and C4. The groups were divided according to the opaquer brand, the number of opaquer coats (one or two), and the thickness of the resin composite layer (0.5 or 1.0 mm). The color measurements were made by a reflectance spectrophotometer (SP60, EX-Rite). The color difference between the opaquer + resin composite + background and a reference background was calculated using the CIEDE2000 formula. ANOVA and Tukey's post hoc test (α=0.05) were used to analyze the ΔE00 mean values. A bivariate analysis was used to determine the association between dependent and independent variables. The masking ability was rated by the ΔE00 visual thresholds of acceptability and perceptibility (Excellent Match: ΔE00 ≤ 0.8; Acceptable Match: 0.8 < ΔE00 ≤1.8; Moderately Unacceptable Mismatch: 1.8 < ΔE00 ≤ 3.6; Clearly Unacceptable Mismatch: 3.6 < ΔE00 ≤ 5.4; Extremely Unacceptable Mismatch: ΔE00 > 5.4). The mean ΔE00 values ranged from 0.5 to 5.52. Masking ability was affected by the opaquer brand, thickness of the resin composite layer, and background shades. Most of the combinations that achieved either excellent or acceptable masking ability were obtained with combinations composed of one or two coats of opaquer and a 1.0-mm-thick resin composite layer for all backgrounds except C4. Acceptable results were also obtained for combinations with 0.5-mm-thick resin composite over C2, A3, and A3.5 backgrounds.

Influence of fluorescent and opalescent properties of resin composites on the masking effect

The objective of this study was to determine the influence of fluorescent properties in the reflectance and transmittance modes and opalescent properties and translucency under ultraviolet (UV)-included and -excluded conditions on the masking effect of commercial resin composites quantitatively. Color and spectral distribution of seven resin composites (14 shades) of 1-mm thick were measured in the reflectance and transmittance modes under UV-included and -excluded conditions. For the fluorescence evaluation, subtraction spectra by the inclusion and exclusion of the UV component of the illumination in the reflectance and transmittance modes were calculated. Opalescence parameter (DeltaO*(ab)) was calculated as the difference in yellow-blue (Deltab*) and red-green (Deltaa*) coordinates between the reflected and transmitted colors under UV-included and -excluded conditions. Under UV-included and -excluded conditions, translucency parameter (TP) was calculated and masking effect was calculated as the color difference between a specimen over a black tile and black tile itself. Fluorescent and opalescent properties varied by the brand and shade of composites and measurement protocols. Masking effect was correlated with TP values when TP values of materials were obviously different. But when TP values were in the similar range, the opalescent property influenced the masking effect of resin composites. The influence of fluorescent property on masking effect was also confirmed, although the degree of correlation was very low.

Using opaquers under direct composite resin veneers: an illustrated review of the technique

In restorative dentistry direct composite resin materials can be used to conservatively resolve many esthetic problems. Opaque resins are often necessary to mask discolorations and/or dark backgrounds when restoring anterior teeth. This article presents a direct composite resin veneer technique using opaquers. Potential problems with the tone of restorations after the use of opaquers are discussed. Advantages, limitations, and the clinical technique are presented. Training, as well as attention to the technique, contributes to an acceptable result.

CLINICAL SIGNIFICANCE

Resinous opaquers can be used as a valid adjunct to the direct composite resin veneer technique when conservatively restoring dark teeth.

Porcelain for veneers

An ideal porcelain veneer placed on a non-discolored tooth requires the least amount of tooth preparation and the use of a translucent porcelain that interferes minimally with the transmission of light. In contrast, veneering a discolored tooth requires additional tooth preparation and the use of a chromatic or opacious porcelain. This article discusses several criteria for the selection of porcelain for porcelain veneers, including some steps to enhance the esthetic properties of these restorations.

Luminescent veneers

The ultimate esthetic dentistry takes into account the conservation of healthy tooth structure integrated with biologic and long-term functional requirements. Materials and techniques that address these inseparable issues are necessary for true excellence. One such material has been presented for the fabrication of porcelain veneers without the need for overt tooth destruction to create masking ability and without an unsightly opaque appearance.