Objective and subjective whitening response of two self-directed bleaching systems

To evaluate objective and subjective whitening responses of two marketed vital bleaching systems under intended use conditions. MATERIALSA ND METHODS: The randomized clinical trial evaluated 50 adults who received either a combination system with a 3% hydrogen peroxide bleaching gel, pre-formed dual arch tray, dentifrice and oral rinse (Rapid White), or 6% hydrogen peroxide whitening strips (Crest Whitestrips). Efficacy was assessed objectively from L*a*b* tooth color at Days 7 & 14, while subjective, first-person whitening perception was measured by questionnaire. A cumulative multinomial probability model was generated to predict subjective responses from objectively measured tooth color.

At end-of-treatment, adjusted mean deltab* was -2.05 +/- 0.158 for the whitening strip group compared to -0.69 +/- 0.141 for the combination group, with these groups differing significantly (P < 0.0001). This response held across every color parameter and time point in this study. Relative to the combination system, subjects in the whitening strip group rated that product significantly (P < 0.01) more favorably with respect to the amount of whiteness improvement, as well as whitening satisfaction and overall impression. These subjective responses were correlated with objective changes in tooth color measured during treatment. When the deltab* effect was included in a cumulative multinomial probability model, deltaL*, deltaa*, and treatment were non-significant predictors. Odds ratios demonstrate that a subject had 3.3 times (1/0.3003 = 3.33) greater odds of selecting a higher whiteness rating when the value of deltab* was decreased by 1.0 unit (less yellowness). Similar results were noted for whitening satisfaction and overall impression of treatment.