Effect of pH of In-Office Bleaching Gels and Timing of Fluoride Gel Application on Microhardness and Surface Morphology of Enamel

Figure 2

Scanning electron micrograph (SEM) of enamel specimens after third session of treatment (14^th day). (a) Negative control specimen (unbleached). (b) Positive control specimen (2% neutral sodium fluoride) (2% NaF). (c) Specimen bleached with Pola Office. (d) Specimen bleached with Pola Office+. (e) Specimen bleached with Pola Office and treated with 2% NaF. (f) Specimen treated with 2% NaF 24 hr before bleaching process with Pola Office. (g) Specimen bleached with Pola Office+ and treated with 2% NaF. (h) Specimen treated with 2% NaF 24 hr before bleaching process with Pola Office+ (×2,500).

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