抄録
The interest for aesthetic improvement by dental treatment has been growing in patients. Recently, Hi LiteTM (Shofu USA), a new vital teeth bleaching system, has been employed as one of the aesthetic dental treatments in the United States. Nevertheless, the biological effects of vital bleaching to teeth and the surrounding tissues has not been clarified. The purpose of this study was to determine the effect of vital bleaching of human enamel surfaces by using scanning electron microscopy and analytical electron microscopy (SEM-EDS). The medial or distal halves of the axial middle third of teeth crowns were bleached. Untreated medial or distal halves were used as the control group. Enamel surfaces were sequentially bleached several times to determine the repetition effect of the bleaching procedure. The bleaching procedure followed the directions of the manufacturer. Further, enamel surfaces etched by 37% phosphoric acid for 1 min were used as positive controls. The one-time bleached group showed no significant difference in microstructure, when compared with the control group. 3- and 5-time treated groups showed “bubbly” microstructure in enamel surfaces. Furthermore, elemental analysis indicated relatively higher intensities of Ca and P in 3- and 5-time treated groups than the control group. The results of this study suggested that the influences of vital bleaching by Hi LiteTM on hard tissues comprising enamel would be few.
