Fig. 4

NAC improves the extent of teeth whitening and prevents mucosal chemical burns of chair-side bleaching agents in patients. Clinical photographs of teeth after bleaching from patients in the control group (without NAC application) demonstrating VitaShade Classical, Vita Bleach and Portrait Bleach shade guides to match with the color of the teeth were taken. Arrows point to the white lesions in the gingival margins around teeth, one of several representative experiments is shown in this picture (a). Clinical photographs of teeth after bleaching from patients in the NAC group demonstrating VitaShade Classical, Vita Bleach and Portrait Bleach shade guides to match with the color of the teeth were taken. No or much lower levels of white lesions in the gingival margins around the teeth can be seen, one of several representative experiments is shown in this picture (b). VitaShade Classical, Vita Bleach and Portrait Bleach Guide are placed in a value-oriented order and given a score in increasing order from light to dark. Shade increment improvement scores for teeth color were determined by finding the differences of the before and after shade guide score. The scores indicated in the table below were used based on the shade guide. The average score was determined in control and NAC-treated groups and found to have no statistical significance (p = 0.3276) (c) Clinical observations were recorded after bleach whitening treatment of patients in control (H2O) or NAC groups. Assessments were made based on patient’s ability to speak after the procedure due to discomfort, and the extents of whitening of the gingival tissues around the teeth after bleaching (d)