Effect of Wetting Agents on Microhardness, Color, and Gloss of a Nanohybrid Composite after Aging

This study investigated whether wetting agent application alters surface microhardness, gloss, and color stability of a nanohybrid resin composite after simulated aging by brushing or thermocycling. Sixty discs of one nanohybrid resin composite were fabricated and divided into three conditions: no wetting agent, Wetting Resin (WR), or Modeling Resin (MR). Baseline evaluations included Knoop microhardness, color using the CIE Lab* system, and 60° gloss. Aging was performed by either standardized brushing or 10,000 thermocycles (5-55 °C). Post-aging values were compared with baseline data. Statistical analysis used two-way repeated-measures ANOVA/Tukey for microhardness, and nonparametric tests for gloss and ΔE (α = 0.05). Wetting agent application lowered baseline microhardness compared to controls, with MR showing the lowest values. Thermocycling reduced gloss, while brushing increased gloss in WR and maintained it in MR. Sealants also affected color stability, with material- and method-dependent responses. In conclusion, the wetting agent influenced the mechanical and optical behavior of the nanohybrid resin composite in a manner dependent on the agent and aging protocol. These materials reduced surface hardness and produced distinct gloss and color responses to brushing versus thermocycling.