In-vitro Evaluation on Efficacy of Stain Removal for Tooth-whitening Dentifrices

Objectives: The objective of this study was to evaluate the capability of stain removal for two dentifrices those are claimed by the manufacturers to have high performance in tooth-whitening compared with an ordinary dentifrice.
Methods: Nine bovine teeth were randomly divided into three dentifrice groups, Brilliant more (BM: LION, Japan), white ruscello (WR: Zettoc, Japan) and PC Clinica Ma (PC: LION, Japan). BM and WR are claimed to be effective in tooth-whitening, and PC is an ordinary dentifrice. BM and PC contain anhydrous silicic acid A, and WR contains calcium carbonate. We used natural bovine labial enamel. Each teeth was immersed into black tea solution of 10 mL which was made by tea leaf (12 g) and water (90°C, 500 mL). After 6-day immersion the stained surface was subjected to ultrasonic bath for 15 sec, after which L*, a* and b* of the labial surfaces were measured by a colorimeter (Spectro Color Meter SE 2000, NIPPON DENSHOKU, Japan). The surfaces were then brushed using each dentifrice with a power tooth brush (GUM, TS-45, SUNSTAR, Japan) for 60 sec with manual pressure of 150 gf .Then color measurements of the surfaces were done and color differences (ΔE) were calculated from L*, a* and b* before and after the tooth brushing. Means ofΔE for each dentifrice group were statistically treated using ANOVA and Tukey’s multiple comparisons (α=0.05).
Results: Means (s.d) of ΔE were, 22.2 (7.5) for BM, 16.4 (4.0) for WR and 18.2 (10.2) for PC. No statistically significant differences were seen among three dentifrices (p>0.05).
Conclusions: Under the limited condition of this study, no significant differences were found in stain removal capability among three dentifrices in spite of the facts that two of them were claimed by the manufactures to have high performance in tooth-whitening.