Abstract:

The efficacy of prevention of extrinsic staining were evaluated for 5 commercial toothpastes by two methods, i.e., UV-Vis absorption spectrometry and colorimetric method. Combined with the quantities of sodium phytate, sodium tripolyphosphate and sodium pyrophosphate in each toothpaste, the differences between the results of the two methods were compared. The results showed that, similar rankings among the 5 toothpastes are obtained for the two methods in evaluating the efficacy of prevention of extrinsic staining; in addition, the total quantity of the three active ingredients （i.e., sodium phytate, sodium tripolyphosphate and sodium pyrophosphate） is positively correlated with the efficacy of prevention of extrinsic staining. Furthermore, pearson correlation coefficient and intra-class correlation coefficients （ICC） were used to analyze the preliminary results obtained from the two methods. In conclusion, moderate positive correlation was found between the two results, i.e., R²=0.725; moreover, ICC=0.852 （P<0.05）, indicating that the results of UV-Vis absorption spectrometry and colorimetric method were statistically consistent.

Key words: toothpaste, prevention, extrinsic stain, UV-Vis absorption spectrometry, colorimetric method, ICC