Repolishing Resin Composites After Bleaching Treatments: Effects on Color Stability and Smoothness

Area of Science:

• Dental Materials Science
• Restorative Dentistry
• Surface Engineering

Background:

• Dental resin composites are susceptible to discoloration from staining agents.
• Bleaching procedures can alter the surface properties of resin composites.
• Surface treatments like repolishing may mitigate adverse effects on composite restorations.

Purpose of the Study:

• To assess the impact of repolishing following bleaching on the color stability and surface roughness of microhybrid and nanofilled resin composites.
• To evaluate the efficacy of repolishing in preventing color changes when composites are exposed to a high-staining beverage (red wine).

Main Methods:

• Two resin composites (microhybrid and nanofilled) were fabricated into discs and subjected to bleaching and repolishing treatments.
• Specimens were aged in red wine or artificial saliva for 30 days.
• Color change (ΔE₀₀) and surface roughness (Ra) were measured at multiple time points using CIE L*a*b* and profilometry, respectively.
• Statistical analysis included repeated measures ANOVA and Tukey's post hoc test.

Main Results:

• Repolished, bleached groups exhibited significantly less color alteration compared to unrepolished, bleached groups when aged in red wine.
• Repolishing generally led to a slight reduction in surface roughness for most groups.
• Nanofilled composites showed greater color change (ΔE₀₀) than microhybrid composites when aged in red wine.

Conclusions:

• Repolishing after bleaching is an effective strategy to enhance the color stability of resin composites against staining, particularly in the context of red wine aging.
• Repolishing contributes to maintaining smoother surfaces on resin composites.
• Material type (nanofilled vs. microhybrid) influences color stability in staining environments.