Effect of Whitening Treatments on Extracted Human Teeth

Objectives: To evaluate the tooth whitening capability of three different peroxide in-office whitening systems on human extracted teeth.
Methods: Forty-five extracted human teeth were randomly divided into three groups (n=15): Group 1: Cavex Bite&White Shade Correction In-Office system, 25% hydrogen peroxide (HP) (Cavex), Group 2: Opalescence^® Boost™ PF, 40% HP (Ultradent Products, Inc), Group 3: Philips Zoom Whitening, 25% HP and use of WhiteSpeed LED Accelerator light (Philips). Tooth Whitening agent was applied on labial surfaces following manufacturer’s instructions. For each sample color coordinates (L*, a*, and b*) were measured using VITA Easyshade Digital Shade Guide at pre-whitening, 1-hr post-whitening (PW), 24hr-PW, 2wk-PW, and 4wk-PW. Total color difference (ΔE) was calculated from baseline. Values were averaged over three trials per treatment group. At each time point, differences in whitening between systems were compared with one-way ANOVA or the Kruskal-Wallis test. P-values less than 0.05 were considered statistically significant.
Results: When groups were compared within the same time points using mean delta E, a statistically significant difference was found: at 1-hour between groups 1 and 2, at 24 hours between groups 1 and 3, and groups 2 and 3. At 2 and 4 weeks mean delta E did not have any statistically significant differences among any groups. Mean L did not have any statistically significant differences among any groups at baseline, 1 hour, or 4 weeks but did show a statistically significant difference between groups 1 and 3 and groups 2 and 3 at 24 hours and similarly between groups 1 and 2 as well as groups 2 and 3 at 2 weeks.
Conclusions: Although significant differences were observed at earlier time points, by 4wk-PW there were no differences in either delta E or L between groups.