Effect of acidic exposure on the optical and mechanical properties of esthetic pediatric restorative materials: an in vitro study

Abstract This in vitro study evaluated the effects of acidic beverage exposure on surface roughness, microhardness, and color stability of three restorative materials commonly used in pediatric dentistry: prefabricated zirconia crowns, 3D-printed crowns, and CAD/CAM crowns. Understanding material behavior under acidic conditions is important for long-term esthetic and functional outcomes in pediatric patients. Ten standardized samples were prepared for each material group, with crown thickness standardized according to the prefabricated zirconia crown A6R model. All samples were immersed in a pigmented acidic solution at 37 °C for seven days to simulate oral conditions. After exposure, surface roughness, microhardness, and optical properties, including translucency and color difference ( ΔE *), were measured. Data normality and variance homogeneity were assessed using the Shapiro–Wilk and Levene’s tests. Parametric or non-parametric statistical tests with appropriate post hoc analyses were applied, with statistical significance set at p < 0.05. Microhardness decreased in all groups, with significant reductions in 3D-printed and CAD/CAM crowns ( p < 0.05). These materials also showed significant increases in surface roughness. Translucency decreased significantly in 3D-printed crowns and increased in CAD/CAM crowns, while no significant change was observed in prefabricated zirconia crowns. Significant ΔE * were detected in 3D-printed and CAD/CAM crowns; however, all values remained within clinically acceptable limits ( ΔE * < 3.3). Acidic beverage exposure adversely affected the surface and optical properties of the tested pediatric restorative materials. Under the conditions of this in vitro study, the tested prefabricated zirconia crowns (NuSmile ® ) showed comparatively greater stability, whereas the tested 3D-printed material (VarseoSmile ® TriniQ) exhibited more pronounced changes. These findings are material-specific and require confirmation through long-term in vivo studies.