桩核直径和材料种类对根管治疗后牙齿抗折强度的影响

目的：本研究的目的为评估不同直径的铸造纯钛桩和玻璃纤维桩对根管治疗后牙齿抗折强度的影响。方法：选择50颗新近拔除的上颌中切牙，根管治疗后将样本完全随机分为5组（n=10）：A组：1．35mm铸造纯钛桩；B组：1．5mm铸造纯钛桩；C组：1．375mm预成玻璃纤维桩；D组1．5mm预成玻璃纤维桩；E组：树脂修复。采用万能材料测试机对样本的抗折强度进行测试，对实验结果进行统计分析并进行断裂模式分析。结果：5组样本的抗折强度如下：A组404．22±73．92N，B组488．17±78．68N，C组280．32±45．23N，D组317．53±50．87N，E组222．76±38．67N。其中C组与D组组问两两比较差异无统计学意义∽〉0．05），其余各组间比较差异均有统计学意义（p〈0．05）。铸造纯钛桩主要表现为不可修复的根中或根尖损伤，而预成玻璃纤维桩主要表现为可修复的根颈部损伤或桩折。结论：铸造纯钛桩核修复上颌中切牙表现为较高的抗折强度，可承受较大载荷，而玻璃纤维桩核修复对牙根的破坏小，有利于患牙的再治疗。

Influence of different diameters and materials of posts on the fracture strength of endodontically treated teeth

Objective： This study was conducted to evaluate the fracture strength of endodontically treated teeth rein- forced with cast titanium posts and prefabricated glass-fiber posts with different diameters. Methods： Fifty recently extract- ed human maxillary central incisors were endodontically treated and randomly divided into 5 groups of 10 specimens each： Group A： 1.35mm diameter of cast titanium post; Group B： 1.5mm diameter of cast titanium post; Group C： 1.375mm diame- ter of prefabricated fiber post; Group D： 1.5mm diameter of prefabricated fiber post; Group E： resin restoration. All speci- mens were subjected to fracture resistance testing in a universal testing machine, statistical analysis was performed and the fracture modes were analyzed. Results： The mean fracture resistance of five groups as follows： 404.22± 73.92N for group A, 488.17± 78.68N for group B, 280.32± 45.23N for group C, 317.53± 50.87N for group D, 222.76± 38.67N for group E. The fracture resistance of restored teeth between group C and group D had no statistically significant difference（P〉 0.05）. The fracture resistance of the rest palrwise group comparisons had statistically significant difference（P〈0.05）. Most of cast post samples fractured at the root middle or apical portion, while most of the fiber post samples fractured at the root cervical or post fracture, which could be retreated. Conclusion： Human maxillary central incisors restored with cast posts could bear higher fracture load and fiber post could protect the root from fracture preferably.