| Summary: | 碩士 === 臺北醫學大學 === 口腔科學研究所 === 94 === Chemo-mechanical removal system is a minimally-invasive treatment for dentin caries. The main component of the system, sodium hypochlorite, however, would destroy the dentin collagen structure to the point that following bonding with resin became poor and unsatisfied. The purpose of this study is to explore the possibility of utilizing zinc chloride, replacing the sodium hypochlorite, not only to dissolve the collagen but also stabilize the protein structure during the dentin caries removal process. Several chemical agents, such as acetic acid, sodium hypochlorite and zinc chloride, were used to realize and compare their influences on type I collagen structure. The results showed sodium hypochlorite dissolved the collagen much more effectively than acetic acid and zinc chloride does in the static environment. However, there was no clear difference among these three agents with the mechanical aid, such as ultrasonic or shacking. After completely dissolution of collagen, its secondary structure and the polypeptide chain were only preserved in acetic acid and zinc chloride solution, observed by circular dichroism and SDS-PAGE. This study also established artificial demineralized dentin to evaluate the removal efficiency of zinc chloride by using SEM/FESEM and FT-IR. The results showed zinc chloride could be used to remove collagen fibers after dentin demineralization and there was no influence on collagen secondary structure, since the major FT-IR functional group absorptions (1662、1637、1553 cm-1) were still be observed. This study recommended the use of 0.1～5 wt% of zinc chloride as an effective ingredient for the chemo-mechanical dentin caries removal system.
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