Fig. 7
From: Ex vivo comparative study of at home bleaching products on whitening efficacy and enamel integrity
Effect of at-home bleaching treatments. The histograms show the means ± standard deviations of spectrophotometric brightness measurements, expressed as optical density (O.D.), taken before (serving as control values) and 48 h after the treatments. The adopted method focuses exclusively on brightness, interpreted as an index of light reflection in a grayscale spectrum: 0 corresponds to absolute white, while − 100 corresponds to absolute black. The symbols * and ** indicate, respectively, a significant difference (p < 0.05) and a highly significant difference (p < 0.0001) according to the Student’s t-test (n = 24), comparing tooth brightness before (left column with more intense colour) and after (right column with paler colour) bleaching treatments. The x-axis labels represent the treatment groups.
