不同桩核系统修复对根管治疗牙的影响

目的 比较非金属桩核系统和金属铸造桩核修复后牙体的抗折强度及牙折形式。方法 对24颗离体上颌尖牙行根管治疗并从唇侧釉牙骨质界冠方2．0mm处截冠后随机分为四组，分别用u．m.Aestheti-plus纤维桩系统、C-Post纤维桩系统、Cosmopost瓷桩系统、Ni-Cr合金铸造桩核进行桩核及铸造金属全冠恢复外形，自凝塑料包埋后，固定于生物力学试验机上测试实验牙的抗折强度并观察其折裂类型，应用SPSS分析软件进行统计学分析。结果 Cosmopost瓷桩系统修复后牙体抗折强度与Ni-Cr合金铸造桩核系统无差别，但明显高于u．m．Aestheti-plus纤维桩系统和C-Post纤维桩系统，后两者之间无统计学差异；Fisher’s精确概率法结果显示：三种非金属桩核组牙体的折裂形式与Ni-Cr合金铸造桩核组存在统计学差异。结论 在保留2．0mm牙本质领的情况下，三种非金属桩核系统修复根管治疗牙的抗折强度，均能满足临床要求；三种非金属桩核系统均有利于牙根的保护。

Fracture resistance and failure patterns of four different post - core systems restored in endodontically treated teeth

Objective To compare the fracture resistance and failure patterns of four different post-core systems in endodontically treated teeth.Methods Twenty-four extracted human maxillary canines were endodontically treated and the crown of the teeth was sectioned at 2.0mm above the labial cement enamel junction.The teeth were randomly and equally divided and restored with u.m.Aestheti-plus fiber post-core-crown system,C-Post fiber post-core-crown system,Cosmopost post-core-crown system(zirconium ceramic),and Ni-Cr cast metal post-core-crown system,respectively.All the teeth were embedded in acrylic resin blocks.Loads were applied on the samples at the palatal of crown with 135degrees and measured with CMT7104 universal load-testing machine.Results The fracture loads of Cosmopost and Ni-Cr post-core system group were significantly higher than that of the two fiber post-core systems group.However,the fracture of the three non-metal post-core system group was mostly repairable while the fracture of the cast metal post-core system group was catastrophic.Conclusion The three non-metal post-core systems may be better in prevention of tooth root from fracture.