Fig. 3

NAC does not interfere with the teeth whitening ability of the bleaching agents. 8-week old male rats were divided into three groups; No bleaching agent- control (left panel) (n = 3), bleaching agent only (middle panel) (n = 3) and bleaching agent with NAC (20 mM) (right panel) (n = 3). After 4 h of treatment as described in Materials and Methods, the teeth were washed with sterilized water and photographs were taken to demonstrate differences in the color and shade of the teeth within the three groups before and after bleaching (a). Rat gingival tissues were treated with bleaching gel in the presence and absence of NAC for 4 h after which the tissues were washed with sterilized water and photographs were taken to demonstrate the differences in tissues between the two groups. The arrows point to the significant white lesions in the gingival tissues of the rats treated with bleaching gel alone and much less in rats which were treated with the bleaching gel and NAC (b)