Comparisons of optical characteristics between 3D printed dental resins and resin composites

To compare the optical characteristics of 3D-printed resins and conventional resin composites, focusing on color differences, whiteness index, and translucency under varying specimen thicknesses and polishing conditions.

A total of 240 disc-shaped specimens (10 mm diameter, 2-4 mm thickness) were prepared using four brands each of 3D-printed resins and resin composites. Color measurements (L*, a*, b*) were performed using a benchtop spectrophotometer before and after polishing. Color differences (ΔE₀₀) were calculated using the CIEDE2000 formula, and both whiteness index and translucency were assessed. Statistical analyses included paired t-tests and Kruskal-Wallis tests (P< 0.05).

Significant color differences were observed among the different brands, even with identical shade designations and polishing conditions. Polishing reduced ΔE₀₀ values but most remained above the acceptability threshold. Resin composites exhibited smaller color differences than 3D-printed resins, while comparisons between the two types showed the largest discrepancies. Translucency decreased with increasing specimen thickness and varied significantly across materials, with 3D-printed resins generally showing higher whiteness indices. The findings suggest a need for greater standardization of optical properties in esthetic restorative materials.

Substantial color and translucency differences exist among materials with identical shade designations. Clinicians should consider these variations to ensure esthetic consistency, highlighting the need for improved standardization in restorative materials.