Assessment of toothbrushing, bleaching pen and bleaching mouthwash in removing stains from tooth structure and single-shade resin composite

The purpose of this study was to evaluate the ability of bleaching pen and bleaching mouthwash to remove coffee stains from teeth surfaces and single-shade resin composite restorations by assessing their Vita Classic shades, changes in the Shade Guide Units (ΔSGU) and color differences (∆E00). In addition, a control group subjected to simulated toothbrushing with non-whitening toothpaste was included for comparison. Class V cavities were prepared in the labial surfaces of 30 extracted sound anterior teeth and restored with single-shade resin composite. The restored teeth were immersed in coffee at 37 °C for 12 days. The stained restored teeth were randomly distributed into three groups (n = 10): Group 1: teeth subjected to simulated toothbrushing with non-whitening toothpaste for one week (control), while groups 2 and 3 were divided according to the bleaching system applied for one week as follows: Group 2: bleaching pen and Group 3: bleaching mouthwash. Using a spectrophotometer (Vita Easy Shade V, Germany), the color was measured before and after coffee staining as well as after toothbrushing or bleaching in each tooth at the middle 1/3 (tooth surface) and cervical 1/3 (restoration). The assessment was performed in two approaches: (a) Vita Classic shades which were used to calculate ΔSGU (b) Color parameters which were utilized to assess the color difference (ΔE00). After coffee staining, the color changes were higher in the teeth surfaces (ΔSGU = 7 and ΔE00=23.8) than restorations (ΔSGU = 4 and ΔE00=8.3). These color changes were unacceptable in both the teeth and resin composite restorations (exceeding the acceptability threshold; ΔE00=1.8). The effect of toothbrushing in removing coffee stains was significantly lower than the bleaching pen and the bleaching mouthwash in both resin composite restorations and teeth (least ΔE00, P = 0.0001). After toothbrushing, the shade of the stained restorations did not change than that after coffee (ΔSGU = 0), while the shade of the stained teeth became slight lighter but still darker than the baseline. After applying the bleaching pen or the bleaching mouthwash, the color returned to the baseline in both the restorations and teeth (ΔSGU = 0). Using the ΔE00 to compare the stain removal potentials of both bleaching pen and bleaching mouthwash, there were no significant differences between them in both resin composite restorations and teeth at cervical and middle one-thirds (P = 0.1 and 0.2, respectively). Toothbrushing with non-whitening toothpaste partially reduced coffee stains, but not completely. In contrast, bleaching pens and bleaching mouthwashes effectively removed coffee discoloration from both teeth and single-shade resin composite. Color changes could be assessed using the Vita Classic shade guide unit differences (ΔSGU) and color difference (ΔE₀₀).