Development of Low-Hydrolytic Polyurethane Root Canal Obturation Material: Mechanical Properties, Cytotoxicity and Hydrolysis
Date Issued
2009
Date
2009
Author(s)
Chou, Fang-Ju
Abstract
Conventional root canal materials do not have enough dentinal adhesion and can not achieve the ideal sealing properties. Our research team has developed the polyurethane root canal obturation system containing ZnO/TPU cone and dual cured urethane acrylate(UA) sealer. Although these materials has good mechanical properties and bonding strength to dentin, the cytotoxicity and hydrolytic stability are questioned. The purposes of this study was to develop the low hydrolytic polyurethane root canal obturation system by replacing the PBA polyol with PC polyol and investigate the mechanical properties、bonding strength、cytotoxicity and hydrolysis of PBA and PC-based polyurethane root canal obturation system. The results showed that the PC-based ZnO/TPU cone can not be used in humen because the low melting point, but the PC-based urethane acrylate sealer fits the clinical use. In the push-out bonding test, the results revealed that PBA-based UA sealer/ PBA-based PU cone and PC-based UA sealer/PBA-based PU cone have the higher bonding strength than other commercial products. From cytotoxicity and hydrolysis evaluations, PBA-based ZnO/TPU cones have better biocompatibility than GP cones and much lower hydrolysis than ResilonTM. The PBA-based UA sealer has good stability to hydrolysis but has high cytotoxicity even in aged specimens. We estimate the reason is that the PBA-based UA sealer does not have good interaction with the AIBN and the residual AIBN causes the cytotoxicity. The PC-based UA sealer has good stability to hydrolysis and the cytotoxicity decreased at the fresh and aged specimens. We conclude that PBA-based ZnO/TPU cones and PC-based UA sealer have high potential for clinical use, and the thermal property of PC-based ZnO/TPU cone and the initiators of PBA-based UA sealer should be improved and changed.
Subjects
Thermal polyurethane
Push-out bonding test
Cytotoxicity
Hydrolysis
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