| Summary: | 碩士 === 臺灣大學 === 臨床牙醫學研究所 === 98 === The standard root canal filling is a combination of sealers with gutta-percha cone. The sealers are responsible for the principal functions of the final root canal filling: sealing off of the root canal system, entombment of remaining bacteria and the filling of irregularities in the prepared canal. However, conventional root canal sealers do not have enough adhesion to dentin and gutta-percha cone. Our research team has developed dual-cured urethane-acrylate (UA) sealer. Although theses materials have good handling characteristics and bonding strength, the previous study showed they had high cytotoxicity. Therefore we synthesized the novel UA sealer by modifying the synthetic procedure and replacing the AIBN with AMBN as thermal initiator. The purposes of this study were to investigate the degree of conversion, cytotoxicity, bonding strength and physical properties of UA sealer with AMBN and AIBN as thermal initiator. The results showed UA sealer with AMBN as thermal initiator has higher degree of conversion. In cytotoxicity, push-out bonding, solubility and dimensional change test, there were no significant differences between UA sealers with different thermal initiator. And the PC-based UA sealer has higher degree of conversion, lower cytotoxicity、solubility and dimensional change than PBA-based UA sealer and commercial products. We conclude that AMBN is a more suitable thermal initiator than AIBN and PC-based UA sealer with AMBN as thermal initiator has high potential for clinical use.
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