Effects of mouthwashes on color stability of bleached teeth

Bleached teeth are susceptible to discoloration. The aim of this study was to evaluate discoloration of bleached teeth following short-term use of several mouthwashes. In this In-vitro experimental study, 48 extracted maxillary central incisorswere selected and divided into four groups of 12. All the teeth were subjected to external bleaching with 38% hydrogen peroxide (H2O2). After bleaching, the teeth were immersed in in distilled water (control group or group 1), chlorhexidine (CHX; group 2), Irsha (group 3) or Persica (group 4) for three, seven and 14 days. The color change was assessed by a spectrophotometer at each time point and reported as 6E1, 6E2 and 6E3. The results were analyzed by paired t-test, repeated measures ANOVA, one-way ANOVA and LSD test. Different mouthwashes (p=0.043) and immersion times (p=0.038) caused significantly variable color change in bleached teeth. After 14 days of immersion, the color change of samples in Persica group had significant differences with that of other groups (p<0.000). The results of repeated measures ANOVA was only significant for the Persica group indicating significant color change over time. Thus, paired t-test was applied for pairwise comparison of the time points, which revealed significant differences between 6E1 and 6E3 and also 6E2 and 6E3 (p<0.05). Persica mouthwash would cause significant discoloration in recently bleached teeth.