Evaluation of the feasibility of OrangeⅡ as a tooth staining and bleaching indicator

• Main Authors: Shih-Hao Huang, 黃士豪
• Other Authors: 林俊彬
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/08881373996182039517

碩士 === 國立臺灣大學 === 臨床牙醫學研究所 === 93 === Among current methods for estimating the effectiveness of tooth bleaching, randomized controlled clinical studies provided the most effective results. Nevertheless, there is still a need for an appropriate experiment method prior to complicated clinical studies. In the past, bleaching results were estimated by observations on tooth staining caused by blood or tea. However, because of the difference between stain intensity and the tooth itself, it was hard to gain accurate estimates from those experiments. Therefore, the purpose of this study was to search an appropriate indicator as well as to design an appropriate tooth staining and bleaching protocol, which can be used to assess the effectiveness of tooth bleaching with higher accuracy. Our study consisted of two parts. The first part was to select the appropriate dye that had similar structures to the chemical agents that normally cause tooth staining. The correlation with these artificial dyes and its liability to tooth staining and subsequent tooth bleaching was evaluated. The second part was to assess the effectiveness of two different hydrogen peroxide catalysts (Fe@Sodium-Y and Mn@Sodium-Y) in bleaching the stained tooth. This study gave us an insight into the difference in the characteristics of the two hydrogen peroxide catalysts. The results revealed that all selected dyes: Rhodamine B, Fe (III) phthalocyanine and Orange II, would cause the tooth discoloration and could be bleached with hydrogen peroxide. However, no relationship between color changes and time was noted when using Rhodamine B. Moreover, it was noted that the stain caused by Rhodamine B was more difficult to bleach. Fe (III) phthalocyanine reacted with hydrogen peroxides too quickly to be considered as an indicator. On the other hand, Orange II was the most appropriate indicator among those three selected dyes used in the stained tooth and test tube. In the second part of study, after adding in the catalyst, we observed an increase of hydrogen peroxide activity in both stained tooth and test tube methods. In the orange II stained tooth, it is difficult to distinguish the catalysis ability between Fe@Sodium-Y and Mn@Sodium-Y. But catalysis ability can be verified in the test tube of Orange II. In conclusion, Orange II was an appropriate dye considered as an indicator for tooth staining and bleaching not only because it had similar structure to clinical tooth stain, but also it did cause tooth staining and could be bleached. In addition, it was able to differentiate the activeness of hydrogen peroxide under the different conditions. Finally, we suggest tentatively screening out catalysts of hydrogen peroxide with application of Orange II before proceeding with complicated and expensive clinical studies. Unfortunately, this assessment may only act as a rough estimation as the chemical reactivity in vitro may not exactly imitate the complicated clinic environment. Therefore, more research is required to eliminate the potential differences between two results needs.