Comparison of Optical Properties in Single-Shade and Multi-Shade Composite Resins

This study aimed to evaluate the differences in optical properties, such as color and translucency, between single-shade composite resins (Omnichroma) and multi-shade composite resins (Filtek Z350XT). Furthermore, the study assessed the influence of the surrounding structure’s shades on the shade matching of Omnichroma. Two types of disc-shaped specimens were prepared: Single specimen (diameter, 8.0 mm; thickness, 1.0 and 2.0 mm), consisting of either Omnichroma or Filtek Z350XT in the A1B, A2B, and A3B shades, and dual specimen (diameter, 8.0 mm; thickness, 2.0 mm), featuring a bottom layer (diameter, 8.0 mm; thickness, 1.0 mm) of Filtek Z350XT in the A1B, A2B, and A3B shades, and a top layer (diameter, 8.0 mm; thickness, 1.0 mm) filled with Omnichroma. Commission Internationale d’Eclairage L*a*b* color measurements and calculations for color differences (ΔE*ab) and translucency parameters (TP) of each specimen were performed. Omnichroma exhibited a lighter, more greenish, and blueish color compared to the Filtek Z350XT in A1B, A2B, and A3B shades. With increased thickness, Omnichroma became more yellowish, whereas Filtek Z350XT became less yellowish. Additionally, when Omnichroma was applied over Filtek Z350XT in dual specimens, the yellowness increased further beyond Omnichroma’s original yellowness level. Consequently, Omnichroma achieved clinically acceptable shade matching, especially in the A3 shade, because it aligns well with the original high yellowness of the A3 shade. Additionally, Omnichroma’s superior shade-matching ability was attributed to its higher translucency compared to Filtek Z350XT. Therefore, Omnichroma might be considered useful in pediatric dentistry by simplifying the shade selection process.