# Color Stability of Resin Composites Immersed for Different Durations in Alcohol-Based and Alcohol-Free Mouthwashes: An In Vitro Study

## TL;DR

This study found that alcohol-based mouthwashes can cause noticeable color changes in dental resin composites, with some materials being more affected than others.

## Contribution

The study compares the color stability of three resin composites in alcohol-based and alcohol-free mouthwashes over time.

## Key findings

- All resin composites showed color variation exceeding the clinical threshold after immersion.
- Filtek Z350XT was most affected by alcohol-based mouthwashes.
- Tetric N-Ceram showed increased color variation over time in alcohol-based mouthwash.

## Abstract

Alcohol in some mouthwashes can dissolve the polymer chain of resin composites, potentially altering their properties. The aim was to evaluate the color stability of resin composites immersed for 24 hours and 7 days in alcohol-based and alcohol-free mouthwashes.

This experimental, longitudinal, in vitro study included 90 resin composite discs divided into three equal groups (n = 30): Filtek Z350XT, Tetric N-Ceram, and Opallis. Each group was split into two equal subgroups (n = 15) and immersed in Listerine Zero and Listerine Cool Mint. Color variation was recorded with a Vita Easyshade spectrophotometer after 24 hours and 7 days of immersion. Welch’s robust ANOVA with an intergroup factor and Student’s t-test for related samples were used, with significance set at p<0.05.

There was no significant color variation when comparing the effect of alcohol-based and alcohol-free mouthwashes on each resin composite (Opallis, Tetric N-Ceram, and Filtek Z350XT) at both 24 hours (p>0.05) and 7 days (p>0.05), although the average color variation in all samples exceeded the clinically accepTable threshold (ΔE > 3.3). When comparing resins immersed in alcohol-based mouthwash, Filtek Z350XT showed greater color variation at 24 hours (p<0.05) and 7 days (p<0.05). Tetric N-Ceram resin immersed in alcohol-based mouthwash significantly increased color variation (p = 0.036) between 24 hours and 7 days.

In this in vitro study, all evaluated resin composites showed color variation exceeding the clinically accepTable threshold. Filtek Z350XT was the most susceptible to color change following exposure to alcohol-based mouthwashes, while Tetric N-Ceram showed a significant increase in color variation between 24 hours and 7 days. These findings suggest that the presence of alcohol in mouthwashes could negatively affect the color stability of certain resin composites.

Key words:Nanohybrid composite, comparative study, dental materials, resin composite, mouthwashes.