In vitro comparison of surface roughness and gloss of prefabricated zirconia crowns before and after simulated brushing

Background : Prefabricated zirconia crowns (PZCs) are widely used in pediatric dentistry due to their superior esthetics and durability. However, limited information is available regarding their surface behavior after long-term brushing. This study aimed to evaluate and compare the surface roughness (Ra) and gloss values of three different PZC brands—NuSmile, ProfZr Crown, and Kids Crown—before and after brushing. Methods : Thirty PZCs (n = 10 per group) were embedded in transparent cold-cure acrylic blocks, with the labial surface oriented parallel to the ground to standardize positioning for the brushing procedure. Specimens were subjected to standardized brushing using an oscillating-rotating electric toothbrush and low-abrasive children’s toothpaste. Surface roughness was measured using a contact profilometer, and gloss was assessed with a glossmeter. Measurements were recorded before and after brushing. Intragroup and intergroup comparisons were performed using Wilcoxon, Kruskal-Wallis, and analysis of variance (ANOVA) tests depending on data distribution ( α = 0.05).