Optical behavior of one-shaded resin-based composites

Abstract

Objective: To evaluate optical properties, and translucency and opalescence parameters of one-shaded resin-based composites.

Methods: Three one-shaded resin composites (OM - Omnichroma; VP - Venus Pearl; and VD - Venus Diamond) and a group-shaded resin composite (FU- Filtek Universal A2) were used. Three composite discs from each material were fabricated for each of the following thickness: 0.5, 1.0 and 2.0 mm. Diffuse reflectance was measured against white and black backgrounds using a calibrated spectroradiometer, CIE D65 illuminant and the CIE 45°/0° geometry. Translucency parameter (TP) was calculated using ΔE_ab ^* and ΔE₀₀. Scattering (S) and absorption (K) coefficients and transmittance (T%) were calculated using Kubelka-Munk's equations, and a reflection spectrophotometer was used to measure the opalescence parameter (OP). Data was statistically analyzed using Kruskal-Wallis, Mann-Whitney tests, and VAF coefficient.

Results: Spectral distributions of S, K and T were wavelength dependent, showing significant differences between materials of the same thickness and for different thicknesses of the same material (p < 0.001). OM showed the greatest translucency values for all thicknesses. Translucency decreased as thickness increased with statistically significant differences (p < 0.005). Values of ΔTP_ab and ΔTP₀₀ between thicknesses were above of translucency thresholds for all materials. VP and VD showed the lowest OP values.

Significance: One-shaded resin-based composites showed different optical behavior than the group-shaded resin-based composite. Understanding the optical behavior of the one-shaded resin-based composites is essential to optimize their clinical performance.

Keywords: Absorption; Group-shaded resin-based composite; One-shaded resin-based composite; Opalescence; Scattering; Translucency; Transmittance.