The Effect of Neutral Sodium Fluoride, Casein Phosphopeptide-Amorphous Calcium Phosphate, and Nano-Carbonate Apatite on Enamel Surface Roughness and Staining after Home Bleaching

Purpose: To investigate the effect of neutral sodium fluoride gel (Flor-Opal), Casein phosphopeptide-amorphous Calcium Phosphate is containing paste (GC Tooth Mousse) and nano-carbonate Apatite Paste (n-CAP), on enamel surface roughness and staining ability after home bleaching in vitro. Material and Methods: Eighty enamel specimens were divided into four groups according to enamel surface treatments that were applied after bleaching (n=20). Group 1 (control group) kept in artificial saliva, group 2 assigned to Flor-Opal gel, group 3 for GC Tooth Mousse and group 4 for n-CAP. Baseline average roughness (Ra1 ) of all surfaces was measured using Talysurf Intra 50 instrument profilometer, and the initial color of the specimens (ΔE) was recorded using Color Eye 7000A Spectrophotometer. The specimens were subjected to bleaching for 2 weeks with 10% carbamide peroxide. After bleaching, the average surface roughness (Ra2) and the color difference (ΔE1) measurements were retaken. Then, surface treatments were applied for 2 weeks according to manufacturer instructions for the four groups then the third average surface roughness (Ra3) was recorded. After that, specimens were stained with coffee 10 minutes per day for 2 weeks. Finally, measurements of color differences after staining were evaluated (ΔE2). Results: Statistically significant increase in surface roughness and color change of all enamel specimens were noticed after bleaching. After the application of the three surface treatments, enamel treated with n-CAP showed a significant reduction in surface roughness (P=0.002) and recorded the lowest color change after staining (ΔE2 =4.1). The treatment of bleached enamel surfaces with Flor-Opal and GC Tooth Mousse did not significantly reduce the increased roughness resulted from bleaching (p=0.57 and 0.08 respectively). However, no significant difference in color was found between the specimens treated with Flor-Opal, GC Tooth Mousse, and specimens treated with n-CAP after staining. Conclusions: N-CAP was effective in reducing enamel surface roughness resulted from bleaching. Also, n-CAP was able to reduce enamel re-staining after bleaching.