Effect of modeling liquids on surface roughness, gloss, and color stability of a nanohybrid resin composite: an in vitro study

This study aimed to evaluate the effects of different modeling resins on the surface roughness, surface gloss, and color stability of a nanohybrid resin composite. Forty disk-shaped specimens (10 mm diameter × 2 mm thickness) were fabricated from a nanohybrid resin composite (Estelite Asteria). The samples were divided into four groups ( n = 10): control (no modeling liquid), Modeling Resin (Bisco Inc., Schaumburg, IL, USA), GC Modeling Liquid (GC Corporation, Tokyo, Japan), and Composite Wetting Resin (Ultradent Products, South Jordan, UT, USA). Specimens were prepared using incremental layering, and modeling liquids were applied using a microbrush between the composite increments to facilitate sculpting. After polymerization, all specimens were polished using a standardized Sof-Lex Polishing System. Surface gloss (GU) was measured using a glossmeter, and surface roughness (Ra) was assessed using atomic force microscopy (AFM). Color stability was evaluated using a spectrophotometer after immersion in a coffee solution for 1, 3, and 7 days. Color change was calculated using the CIELAB color system (ΔE) formula. Statistical analyses included one-way analysis of variance (ANOVA), Kruskal–Wallis test, and repeated measures ANOVA ( p < 0.05). The surface gloss values did not differ significantly among the groups ( p > 0.05). However, the surface roughness values showed significant differences between the groups ( p < 0.05), with the GC modeling liquid presenting significantly higher roughness values than the control and Ultra groups. Regarding color stability, the ΔE values increased significantly over time ( p < 0.001), but no statistically significant differences were observed among the groups ( p > 0.05). The use of modeling resins did not significantly affect the surface gloss or color stability of the tested composites. While modeling resins did not significantly affect surface gloss or color stability, certain modeling liquids resulted in a statistically significant increase in surface roughness.