Effect of Staining and Bleaching on Surface Roughness of Different Nano Hybrid Resin Composite Materials

Abstract

Aims: The purpose of this study was to evaluate the effects of staining by coffee and In-office bleaching by 30% hydrogen peroxide on surface roughness of two different Nano Hybrid composite and Omnichroma resin-based composite. Materials and Methods: In this in vitro experimental study, 32disc samples were fabricated from each type of the Nano-Hybrid resin composite materials, each sample measured 5 mm in diameter and 2 mm in height. The samples for each composite group were then subdivided randomly into four subgroups (n=8). In control subgroups , samples were stored in artificial saliva at 37°C for 1 week. Samples of Staining subgroups were stored in a coffee solution for 48h at 37°C. Samples of Staining Bleaching subgroups were stained in a coffee solution for 48 h at 37°C then bleached with 30% H2O2. Samples of Bleaching subgroups were bleached with 30% H2O2. The surface roughness measurements were taken for all samples of each subgroup ; the measurements for control subgroups considered as baseline data. Non-parametric tests were used for statistical analysis at P≤0.05. Results: The surface roughness measurements of all subgroups for both tested materials didn't exceed the critical value (Ra< 0.2 μm) with no significant difference among all subgroups (P >0.05). Conclusion: Surface roughness of the two tested Nano-Hybrid resin composite materials were neither influenced by coffee staining nor by in-office bleaching with 30% H2O2.