In Vitro Fracture Resistance Of Endodontically Treated Anterior Teeth With Varying Ferrule Heights And Configurations And Different Materials Of Post And Core

Objection: Comparing the influence of variety post and core materials and restoration methods on the resistance of anterior residual root, in order to find a better post crown restoration method to improve the resistance of the residual root and protect it better, which can be refered to choose suitable post material for different residual root.Material and methods: Maxillary teeth were prepared as residual roots model. The materials which have the similar physical properties and capabilities as that of the alveolar bone were chosen. The materials and post crown restored maxillary anterior roots made up of our measure and test system. Then test groups were randomly assigned according to make ferrule or not and various materials of dowel and core, after that the models were loaded on and the fracture resistance was recorded at last. This test closely combined the materials and methods used in clinic.The result:1. The fracture resistance of endodontically treated teeth between teeth with no structure defect and teeth restored with common mental post and core had no obviously difference (P＞0.05) .2. The fracture resistance of endodontically treated teeth with ferrule higher than 2mm was superior to teeth without ferrul(P＜0.001) , but no significant difference was detected between teeth with ferrule higher than 2mm and crowned teeth without a dowel and core (P＞0.05)3. The failure mode of teeth restored with glass-fiber post and composite resin core was able to restore. Adversely, the failure mode of teeth restored with common mental post and core was almost unable to restore.4. The fracture resistance of residual dental root with horn-shaped orifice restored with glass fiber-reinforced resin was as effective as teeth restored with common mental post and core and with glass fiber post and composite resin core (P＞0.05).Conclusion:1. If the tooth structure was not damaged after root canal treatment, it can be protected by post and core crown.2. It is better to gain more ferrule (＞2mm) when the anterior residual root is restored. The fracture resistance of endodontically treated central incisor can be improved.3. It is better to choose glass-fiber post and composite resin core when the anterior residual root is restored. The method can not only meet the need of chewing, but also protect the residual root better and avoid fracture again.4. For the residual dental root with horn-shaped orifice, it is better to choose glass fiber-reinforced resin to restore. The method can not only meet the need of chewing, but also has no influence to the residual root protection.