# The Effect of Adhesive Systems on Shade Matching of Composite Veneer

## TL;DR

This study found that different adhesive systems affect the color stability of composite veneers, with bioactive materials showing better resistance to discoloration from beverages.

## Contribution

The study introduces experimental adhesives based on hydroxyapatite and bioactive glass for improved color stability in composite veneers.

## Key findings

- Coffee and Cola caused significant color changes in composite veneers.
- The 4th generation adhesive showed better color stability than the 7th generation in certain regions.
- Bioactive glass-based adhesives showed more discoloration than hydroxyapatite-based ones.

## Abstract

Objective: This study aimed to assess the impact of different adhesive systems on the color stability of composite veneers following their exposure to various common beverages. Materials and Methods: A single layer of commercially available adhesives (4th and 7th generations) and two experimental adhesives based on hydroxyapatite and bioactive glass were applied, followed by composite restoration on incisor typodonts. The typodonts were prepared with depths of 0.3, 0.5, and 0.7 mm at the cervical, middle, and incisal regions, respectively. Samples from each group were immersed in coffee, Cola, and deionized water, and color stability was analyzed on days 1 and 60. One-way and two-way analyses of variance were performed. Results: The interaction between groups and solutions was statistically significant (p = 0.001) across all tooth regions. Coffee and Cola caused significant color changes (p = 0.001). The 4th generation demonstrated better color stability than the 7th generation in the middle and cervical regions (p-values = 0.083 and 0.003, respectively). The findings showed that the bioactive glass-based bonding agent exhibited greater discoloration than the hydroxyapatite-based adhesive (p = 0.001). Conclusions: The composite thicknesses are influenced differently by adhesives with respect to shade matching. Bioactive materials-based adhesives showed more resistance towards color change than commercial adhesives.