Mandibular Posterior Crossbite Appliance의 적용시 응력분포에 관한 광탄성법적 연구

Photoelastic evaluation of Mandbula Posterior Crossbit Applicance

To investigate the difference of texture exhibited on interproximal enamel surface with each different stripping method and the susceptibility of proximal enamel to demineralization after stripping and the application of a topical fluoride gel and sealant, one hundred human premolars, which were previously extracted for orthodontic reasons were evaluated by means of Scanning electron microscopy and laser fluorescence. The results were as follows 1. No matter what the initial stripping instrument was the furrows that resulted from all the stripping methods were not completely removed by careful polishing. 2. Among the enamel surfaces that were treated with three different initial abrasive instruments, followed by they same polishing method (Sof-LexJ disks), the enamel surfaces that were treated with 700 crosscut carbide bur show(.d the smoothest surfaces. 3. The stripped teeth, no matter what the initial stripping instrument was, were less resistant to initial demineralization than untreated teeth. But no difference in caries susceptibility according to differently stripped methods was found (p (0.001). 4. Teeth treated with APF-gel or sealant were more resistant to demineralization than those treated without other treatment after stripping (p <0.001). 5. Comparing groups treated with APF-gel to groups treated with sealant, the former was more resistant to demineralization than the latter (p (0.05). In conclusion, enamel surfaces that were stripped interproximally were less resistant to demineralization even though various attempts were made to produce smooth, self-cleaning enamel surfaces. Therefore, additional treatment-sealant or calcifying/ fluoridating solution to the stripped enamel surfaces is recommended