Methods: This study obtained the approval of the Showa University IRB committee. (approved number 2011-035). Ten extracted intact human incisors were used in this study. Commercial in-office bleaching gel containing 35% hydrogen peroxide (Hi-Lite, Shofu Japan) was applied to the labial enamel surface according to the manufacturer’s instructions. Namely, the bleaching gel was applied to the surface for 3 min and repeated 3 times on bleaching process. The bleaching process was repeatedly carried out once per week, and then the specimens were stored in artificial saliva at 37℃ up to 6 weeks. Before and after bleaching, the tooth structure of the specimen was observed by using experimental SS-OCT.
Results: In the tendency of SS-OCT images, the obvious laminated structure existed in normal dental tissue of enamel and dentin layer were distinguished. The tooth hierarchical structure is never change throughout bleaching procedure. However, reflected light intensity of SS-OCT images, enamel surface and enamel near enamel-dentin junction, tend to decrease after bleaching.
Conclusions: It is suggest that tendency to decrease of reflected light intensity of SS-OCT images due to oxidation effect. It is a significantly reflect alteration of optical properties of bleached teeth. SS-OCT has the advantage that it allows the user to immediately visualize the teeth image to the patient at chair side and makes something possible to provided comparison of live images with the previously recorded bleaching teeth images. SS-OCT has a potential to become a new tool for teeth bleaching. This study is not to take the statistics.