Methods: This study was a double-blind comparison of two parallel groups of subjects that brushed unsupervised twice daily with different dentifrices for 6 weeks. Stain was measured on the labial surfaces of the incisors by the Modified Lobene Stain Index (MLSI) at entry (baseline) and after 2, 4, and 6 weeks of product use. After balancing for baseline MLSI, gender and tobacco use, 108 healthy adults with existing stain were randomly distributed into two equivalent groups. Each subject was assigned the control dentifrice (Crest® Cavity Protection Regular) or the new test product. Within-treatment comparisons between baseline and other exams were made using matched-pair t-tests, and between-treatment comparisons of MLSI scores from each exam were performed by ANCOVA using baseline scores as covariates.
Results: Within-treatment comparisons showed that the control group MLSI means for the labial surfaces were comparable at all exams and post-treatment changes from baseline were not significant (p > 0.05). However, the test group means were significantly lower than baseline by 16% at week 2 (p = 0.0004), 23% at week 4 (p = 0.00002), and 13% (p = 0.008) at week 6 exams. Between-treatment comparisons resulted in lower MLSI means for the test group than the control group at all exams, and statistically significant differences of 16% after 4 weeks (p = 0.050) and 15% after 6 weeks (p = 0.018) of treatment, favoring the test dentifrice.
Conclusion: A low-abrasivity, dual-phase, sodium bicarbonate dentifrice containing calcium and phosphate was efficacious for removing existing extrinsic tooth stain.
[Supported by Church & Dwight Co., Inc.]