Objective: The objective of this randomized, double-blind, parallel-group clinical study was to compare the tooth whitening efficacy of two tooth whitening gel products--Colgate Simply White Night Clear Whitening Gel containing either 25% carbamide peroxide, or 8.7% hydrogen peroxide--when used once daily at night.
Methodology: Following a baseline tooth shade evaluation using the Vita Shade Guide, qualifying adult male and female subjects from the Central New Jersey area were randomized into two treatment groups, which were balanced for baseline Vita Shade Guide scores, gender and age. The treatment groups were: 1) a tooth whitening gel containing 25% carbamide peroxide; or 2) a tooth whitening gel containing 8.7% hydrogen peroxide. All subjects were given a commercially available, non-whitening dentifrice and a soft-bristled toothbrush at the beginning of the study. In addition, they were also given one of the two tooth whitening gel products. All subjects were instructed to brush their teeth for one minute twice daily (morning and evening) with the non-whitening toothpaste. The subjects were further instructed to apply their assigned tooth whitening gel product once daily at night, per the instructions provided. Evaluations of tooth shade for each subject were repeated after two weeks, and again after three weeks of product use.
Results: Fifty-nine (59) subjects complied with the protocol and completed the three-week study. At both the two-week and three-week examinations, all subjects exhibited statistically significant (p < 0.05) tooth shade lightening relative to baseline tooth shade. Further, there was no statistically significant difference in tooth shade lightening between the two tooth whitening gel products.
Conclusion: The results of this clinical study indicate that after once daily use at night for two or three weeks, a tooth whitening gel containing 25% carbamide peroxide and a tooth whitening gel containing 8.7% hydrogen peroxide both provided statistically significant tooth shade lightening relative to baseline tooth shade. The results also showed that there was no statistical difference in tooth whitening efficacy between the two tooth whitening gel products.