Assessments of a novel bleaching agent containing sodium dithionite: A laboratory study

To initially evaluate the efficacy of a novel non-peroxide-based whitening strip (Dithionite White) on beverage colorants and doxycycline-stained teeth.

In the evaluation of the beverage-stained teeth, two small areas (incisal-enamel and cervical-dentin) were exposed on bovine teeth for staining; the samples were divided into six treatment groups (n= 90) and three treatment protocols. The teeth were immersed for 14 days into six treatment groups: red wine, coffee, cola, tea, soy sauce, and an equal-part cocktail of previously listed colorants. The control group (n= 3) remained immersed in de-ionized water. The teeth were treated twice daily with Crest Whitestrips for 30 minutes and a whitening agent Dithionite White (DW) for 30 and 60 minutes on days 1, 3, 5, 7, and 14; the tetracycline-stained teeth were divided (80 teeth in the study) into eight groups (n= 10). These teeth were bleached daily. The bleaching effectiveness of the blue LED and Red infrared lights was evaluated as well as the use of mouthwash to enhance the bleaching environment. For all groups, the color change was assessed with a spectrophotometer. For the beverage-stained teeth, measurements were taken at baseline pretreatment, post-stain, 1 day, 3 days, 5 days, 7 days, and 14 days posttreatment. For the tetracycline-stained teeth, weekly measurements were obtained for 11 weeks. In each study L*, a*, b* at each period of bleaching was compared to the baseline. The color difference (ΔE) was calculated. The means ΔE were compared with multiple ANOVA tests and a MANOVA test.

In the beverage-stained and doxycycline-stained teeth, both bleaching systems showed color improvement.

The results of this study support the effective use of Dithionite White (non-peroxide based) as an effective bleaching agent. Additional treatment beyond 30 minutes of DW did not significantly increase bleaching results. The adjunctive use of blue and infrared LED lights and alkalizing mouthwashes may enhance bleaching effectiveness.