Composite resin core with prefabrocated fiber posts for endodontically treated teeth

由于龋齿和外伤而进行牙髓治疗的牙齿，通常采用桩核修复，然后冠冠修复，从而恢复牙齿的功能和美观。我们在2002年对几种纤维桩的比例极限和弯曲弹性模量进行了测试，得到了以下结果：这些纤维桩具有与预制金属桩几乎相同的强度，具有很高的弹性和柔韧性。2003年，我们从临床角度做了一个额外的实验。采用Celay系统（Mikrona, Switzerland）制造的模拟人上中切牙80颗，采用堆芯法分为4组；复合树脂桩芯(R)、复合树脂桩芯与预制金属桩（MR）、复合树脂桩芯与纤维桩（FR）和常规铸造桩芯(M)。在构建核心后，制作金属冠并粘合。然后测量每秒加载250N至30万次循环加载前后的断裂强度，并观察记录其断裂模式。结果表明，在循环加载前的堆芯方法中，FR的断裂强度最高，且无根断裂，而金属桩的MR和M则表现为根断裂。循环加载后，FR的断裂强度有所下降，但无统计学差异。综上所述，复合树脂芯与纤维桩具有较强的抗根断裂能力，即使发生根断裂，也有很大的可能性可以保存和修复根。

Endodontically treated teeth due to dental caries and trauma are generally restored with post and cores and then crowned resulting in recovery of their function and esthetics.We examined proportional limit and bending elastic modulus of several kinds of fiber posts in 2002 and obtained the following findings that those posts have almost the same strength as the prefabricated metal post with high elasticity and flexibility.In 2003 we did an additional experiment from the clinical view point. Eighty bovine teeth simulating the human upper central incisors fabricated by Celay system (Mikrona, Switzerland) were prepared and divided into 4 groups by core-buildup method ; composite resin post and core (R), composite resin core with prefabricated metal post (MR), composite resin core with fiber post (FR) and conventional cast post and core (M). After building up cores, metal crowns were fabricated and cemented. Then fracture strength was measured before and after cyclic loading that loaded with 250N at every second until 300,000 times and also their fracture modes were observed and recorded.As a result, FR showed the highest fracture strength in all core buildup methods before cyclic loading and better fracture mode with no root fracture, while MR and M using metal posts indicated root fracture. After cyclic loading, fracture strength of FR decreased but statistically with no difference.In conclusion, composite resin core with fiber post can be higly resistant to root fracture and even if root fracture occurs, the root can be saved and restored in high possibility.