三种桩核系统修复后牙体组织抗疲劳强度体外研究

目的:比较两种纤维根管桩核系统和金属铸造桩核修复后牙体组织的抗疲劳强度和破坏模式。方法:2 4个离体上颌中切牙常规根管治疗术后截除牙冠,随机等分成A、B、C三组,A组用AESTHETI -PLUS石英纤维桩、复合树脂核系统及烤瓷冠修复,B组用C- POST碳纤维桩、复合树脂核系统及烤瓷冠修复,C组用Cr -Co铸造金属桩核进行桩核及烤瓷冠修复,包埋于底座后进行抗疲劳强度的测试,最多测试次数约10 0万次或试件破坏,记录试件破坏时的加载次数以及试件破坏的模式。结果:三种桩核系统修复后的离体牙中均有发生根折,但根折的部位不同,A组另有2个离体牙出现树脂核与牙本质分离,B组另有1例出现树脂核与牙本质分离,而C组除2例根折外,其余6个离体牙未出现明显的牙体组织或修复体的破坏。结论:Cr Co铸造金属桩核系统是一种较为成熟的桩核系统,AESTHETI- PLUS石英纤维桩和C POST碳纤维桩核系统具有一定的临床应用前景,但临床使用纤维桩时仍应考虑其他因素对修复效果的影响。

In vitro study of fatigue test of pulpless teeth restored with three post-and-core systems

Objective:To compare the fatigue strength and failure pattern of extracted teeth restored with three different post-and-core systems.Method:The crowns of 24 extracted maxillary central incisors which accepted root canal therapy were amputated. The roots were divided into 3 groups, A, B and C randomly, the teeth of group A were restored with AESTHETI-PLUS fiber post-core-crown system, group B were restored with C-POST fiber post-core-crown system and the teeth of group C were restored with Cr-Co cast metal post-core-crown system. All the teeth were mounted in resin blocks. Loads were applied on the samples at 135 degrees and tested with fatigue test machine. Result: Two roots fracture in group A, C while the position of the fracture is different. The composite core of other 2 teeth of group A detached from the dentin of the root while there is no obvious failure of teeth or restorations of other 6 teeth of group C. One root of group B fractured at the level of mid-root and the composite core of a tooth in group B detached from the root dentin. Conclusion: Cr-Co cast metal system is a reliable post-core system that can match the clinical demands. Both kinds of fiber post have bright prospect in clinical use in the near future, however, the dentists should take other factors into account, such as the composite core of the system.