Novel Urethane-acrylate Root Canal Sealer: Degree of Conversion, Cytotoxicity, and Physical Properties

根管封填主要以馬來膠錐體搭配封填劑使用，其中使根管系統達到滴水不漏的密封主要是靠封填劑，但傳統各類封填劑與馬來膠體及牙本質之間的黏著並不理想。我研究團隊所研發出的胺酯壓克力樹酯封填劑，有良好操作性質並且與聚胺脂錐體材料及牙本質之間的黏著有優於傳統根管封填劑的表現。然而之前研究顯示胺酯壓克力樹酯封填劑在細胞毒性有很高的變異性，因此我們改變製成過程並將熱起始劑更換為偶氮二異戊晴 (AMBN)。本研究目的為探討以偶氮二異戊晴(AMBN) 為熱起始劑的新型胺酯壓克力樹酯封填劑在聚合程度及細胞毒性表現，並且對於更換熱起始劑後的封填劑進行推離鍵結測試及物理性質測試並與市售材料比較以了解是否仍保有與原來材料相同的優勢。結果顯示以 AMBN 為熱起始劑之胺酯壓克力樹酯封填劑有較高的聚合程度，而且在光源無法到達處仍是可以藉著光聚合所產生的熱以及37 ℃的環境下達到聚合；在細胞毒性測試、推離鍵結測試、溶解度及體積穩定度的測試結果，使用不同熱起始劑的胺酯壓克力樹酯封填劑之間並無顯著差異。而其中PC合成的胺酯壓克力樹酯封填劑比起PBA合成的胺酯壓克力樹酯封填劑及市售材料 EndoREZ™ 及 Epiphany™ 有較高的聚合程度、較低的細胞毒性以及較好的穩定性。因此，依據聚合程度測試得知AMBN較適合做為胺酯壓克力樹酯封填劑的熱起始劑；而在細胞毒性、聚合程度及物理性質方面，使用AMBN為熱起始劑的PC合成胺酯壓克力樹酯封填劑極具潛力可以應用於未來的臨床根管治療。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