The effects of vital whitening agents on the surface properties of three different restoration materials.

The aim of this study was to evaluate the effects which can occur on the physical properties of 3 different restorations (amalgam, GIC, composite) with the application of carbamide peroxide whitening. A total of 99 samples were prepared. The samples were randomly separated into 3 groups of 30 with 10 of each of the 3 materials. Each of these groups was examined in a different test device (G1: profilometer, G2: AFM, G3: spectrophotometer). The remaining 9 samples constituted a 4th group for SEM examination. 16% carbamide peroxide was applied at 6 hour intervals for a total of 14 days. A statistically significant increase was determined in the surface roughness (Ra-µm, Ra-nm) and colour change (ΔE) values in all the restorations. The least colour change was observed in composite. In the SEM, no significant surface change was observed in amalgam and composite, whereas micro-cracks were observed to have formed on the GIC surface.