Effect of Fluoride-releasing Resin Fissure Sealant on the Decalcification Layer of Root Dentin

本研究的目的是评估氟释放胶在预防龋齿和父亲进展方面的效果。该密封胶含有甲基丙烯酰氟和甲基丙烯酸甲酯的共聚物，通过水解反应释放氟离子（f -密封胶）。不含氟释放共聚物的密封胶（c -密封胶）也被估计为对照。牙本质块从拔牙的牛牙根部切下。在牙本质表面涂上密封胶后，标本在去离子水中保存7天。机械去除密封胶后，将标本浸入醋酸缓冲液（pH4.0）中40小时。我们还研究了在预脱钙牙本质上应用氟释放密封剂是否能阻止龋样病变的发展。将样品浸泡在pH4.0的醋酸缓冲溶液中12小时进行预脱钙。样品在去离子水中保存7天，并应用密封胶。去除密封剂后，将标本进行后脱钙处理（pH4.0醋酸缓冲液，40小时）。通过显微x线摄影测量硬度和病变吸收深度来评价密封胶的抑制效果。对于健全牙本质，损伤深度的大小顺序为f -密封剂组< c -密封剂组<未处理组。对于脱钙前的牙本质，虽然f -密封剂和c -密封剂的病变深度几乎相同，但它们比未处理的明显变窄。显微硬度测试表明，f -密封剂处理的牙本质损伤比c -密封剂处理的牙本质损伤更硬。结果表明，氟释放剂的应用抑制了暴露根表面龋的产生和发展。

The purpose of this study was to estimate the effect of the fluoride-releasing sealant on the prevention from caries and fathermore progressing. The sealant contains the copolymer of methacryloyl fluoride and methylmethacrylate which releases fluoride ion by hydrolytic reaction (F-sealant). The sealant with no fluoride-releasing copolymer (C-sealant) was also estimated as a control. The dentin blocks were cut from the root parts of extracted bovine teeth. The specimens were stored in deionized water for 7 days after application of the sealant onto dentin surface. After removing the sealant mechanically, the specimen was immersed in acetic buffer solution (pH4.0) for 40 hours. It was also investigated whether fluoride-releasing sealant applied onto pre-decalcified dentin prevents the progress of caries-like lesion. Pre-decalicification was produced by immersion of specimen in pH4.0 acetic buffer solution for 12 hours. The specimen was stored in deionized water for 7 days with the application of the sealant. After removing the sealant the specimen was subjected to post-decalcification ( pH4.0 acetic buffer solution, 40 hours). Inhibitory effect of the sealant was estimated by the measurement of hardness and the depth of lesions absorbed in microradiograph. For the sound dentin, the order of the depth of lesion was F-sealant group < C-sealant group < no treatment group. For the pre-decalcified dentin, although the depth of lesion was almost same between F-sealant and C-sealant, they were significantly narrower than that without any treatment. The microhardness testing showed that the lesion of dentin treated with F-sealant was harder than that with C-sealant. The results suggested that the application of fluoride releasing sealant inhibited the production and progress of caries on exposed root surface.