ABSTRACT
The purpose of this study was to identifu the preventive and the preventive and the progressive inhibitory effects of enamel demineralization with fluoride releasing light-and self-cured orthodontic sealants(FluoroBond), in vitro, under the polarizing light microscope and the scanning electon microscope. The polarizing light microscopic group was subdivided into seven groups(Group A-Group G). The scanning electron microscopic group was also subdivided into seven groups(Group A'-Group G'). For polarzing light microscopic evaluation, longitudinal sections were made longitudinally by Maruto cutter(Maruto Co., Japan) and Maruto grinding machine(Maruto Co., Japan). Sections were examined and photographed by the polarizing light microscope(Olympus Optical Co., Japan) using crossed polars and with the enamel rod longitudinal axis oriented at 45degrees to the extinction position. For scanning electron microscopic evaluation, the specimens were coated with a highly conducting layer of gold palladium in a model Hus-4 high0vacuum evaporator* and examined in an ISI-100B scanning electron microcpe** operated at 20kV. The results of this study were as follows : 1. The mean deoths of artificial carious lesions under a polarized light microscope were Group A(5.08microgram), Group B(47.82microgram), Group C(8.42microgram), Group D(7.20microgram), Group E(85.41microgram), Group F(60.38microgram), Group G(60.13microgram). 2. There were statistically significant differences in Group B compared with Group A, C, and D(p<0.05), and also, in Group E compared with Group F and Group G(p<0.05). 3. Light-and self-cured orthodontic sealants had the preventive effects of enamel demineralization. 4. Light-and self-cured orthodontic sealants had the progressive inhibitory effects enamel demineralization. 5. The time progress of demineralizing agent no ingluecse on the samples of light-and self-cured orthodontic sealants under the scanning electron microscope. 6. There was no difference between the specimens of light-and self-cured orthodontic edalants both in the polarized light microscopic group and in the scanning electron microscopic group. *Hitachi Ltd, Tokyo, Japan **International Scientific Instruments, Santa Clara, Calif.