Tooth Whitening From a Blue Covarine Containing Toothpaste

Objectives: To evaluate the tooth whitening efficacy of a toothpaste containing blue covarine (BC) versus a negative control toothpaste and to investigate the variability of an in vitro model.
Methods: Extracted human incisors and premolars were placed in sterile saliva for two hours. After rinsing with water, baseline tooth colour was measured using a colorimeter. In two studies, tooth specimens were brushed with a slurry of either BC or a negative control toothpaste, rinsed with water and their colour remeasured. Changes in tooth colour were calculated using the WIO tooth whiteness index. The protocol was repeated on four further individual studies using the BC toothpaste. A meta-analysis was used to obtain a robust estimate of the whitening effect of the BC toothpaste. A variance components analysis was used to determine the sources of variation in the BC whitening data.
Results: The mean (s.e.) change in WIO for BC and control toothpaste in study 1 was 1.28(0.32) and 0.38(0.63), and in study 2 was 1.15(0.28) and -0.03(0.39) respectively. There was a statistical significance between BC and control in both studies (p<0.05, ANOVA). The mean (s.e.) change in WIO in the other four studies for BC were 1.32(0.36), 2.39(0.43), 1.50(0.57) and 1.59(0.63). Statistical analysis on all six studies for BC showed a significant (p<0.05, ANOVA) whitening effect from baseline and the mean overall estimate of change in WIO from a fixed effect meta-analysis was 1.50. Variance components analysis showed that 96% of the variability in the WIO data was due to tooth to tooth variation and only 4% was due to experiment to experiment variation.
Conclusions: A toothpaste formulation containing blue covarine gave a significantly greater tooth whitening effect than the control toothpaste. The in vitro model provides a highly reproducible means of tooth whiteness evaluation.