The Effects of Home and Over-The-Counter Whitening Agents on Surface Roughness and Microhardness of High Aesthetic Composites

Abstract

Objectives: The aim of this in-vitro study is to compare the effect of the newly released peroxide-free over-the-counter whitening products and the home bleaching material containing carbamide peroxide, on high aesthetic composites. Materials and methods: In our study, 4 different composites were used: supra-nano(Tokuyama Estelite Asteria), submicron hybrid(Brilliant Ever Glow), nanofil(Filtek Universal Restorative) and finally nano-ceramic(Ceram.x SphereTEC one). A total of 200 disc-shaped composite specimens with 2 mm thickness and 8 mm diameter were prepared using metal molds(n=10). One surface of the samples was polished using Sof-Lex™ XT discs. Composite groups were divided into 5 subgroups as 4 experimental and 1 control groups. Four bleaching products, namely Opalascence Home Type, Mr. Blanc, I-White, Cali White, were used in the experimental groups. It was kept in a drying oven at 37°C to imitate the temperature of the mouth on certain days and hours in accordance with the instructions written in the whitening products prospectus. The surface roughness of the samples was measured with a profilometer and the microhardness values were measured with a fully automatic Micro Hardness Tester. The surfaces were examined with a Scanning Electron Microscopy. Data were evaluated with two-way Variance Analysis and Tukey Test as statistical methods. Results: According to the surface roughness data, Filtek Universal Restorative's I-White subgroup showed the highest average surface roughness value, and Tokuyama Estelite Asteria's I-White subgroup showed the lowest value. There was a meaningful difference between the composite main groups and the experimental subgroups(p<0.05). According to microhardness data, I-White subgroup of Tokuyama Estelite Asteria showed the highest average microhardness value and the lowest value was Brilliant Ever Glow's I-White subgroup. A meaningful difference was observed between the composite main groups and the experimental subgroups(p<0.05). Although OTC bleaching products did not significantly change the surface roughness and microhardness values of composite resins, when SEM analyzes were examined, it was observed that all OTC bleaching products caused more cleft, crack and defect-like changes on the composite surfaces compared to Opalescence home bleaching agent. Conclusions: It can be stated that Filtek Universal Restorative material is the composite that is most negatively affected by whitening materials, while Tokuyama Estelite Asteria composite is the least affected.