热牙胶充填行不同桩核系统修复后牙根的抗折性

背景：由于旁路充填后扁根管形态的复杂性与不规则性，以及桩核对牙体应力变化的特殊性，至今尚未找到一种合理的桩核修复系统适用于扁根管旁路充填后牙体的修复。目的：比较扁根管旁路热牙胶充填后分别行钴铬合金铸造桩核、二氧化锆桩核及CAD/CAM一体化玻璃纤维桩核修复后牙体的抗折能力。方法：获取离体人下颌第一前磨牙(单根)90颗，采用ObturaⅡ&System B热牙胶系统进行根管旁路充填后，随机均分为3组，分别采用钴铬合金铸造桩核、二氧化锆桩核及CAD/CAM一体化玻璃纤维桩核进行牙体修复，再均以钴铬金属全冠修复。测试并记录各组样本折裂强度及折裂类型。结果与结论：钴铬合金铸造桩核组、二氧化锆桩核组抗折能力强于玻璃纤维桩核组(P < 0.05)，前2组抗折能力比较差异无显著性意义。钴铬合金铸造桩核组折裂部位为牙根部，为不可修复性折裂；二氧化锆桩核组折裂部位为牙根颈部与牙根部，为可修复性折裂；玻璃纤维桩核组折裂部位为牙颈部，为可修复性折裂。表明采用钴铬合金铸造桩核进行牙体修复能承受较大的咬合力，但牙根折裂的概率较大；CAD/CAM一体化玻璃纤维桩核修复后牙根折裂的概率较低。中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程

Fracture resistance of different post-and-core repair systems after warm gutta filling

BACKGROUND: Due to the complexity and irregularity of bypass obturation of oval root canal and the particular stress of the post and core to the tooth, we have not yet found a reasonable post crown for dental restoration after bypass obturation of the oval root canal.OBJECTIVE: To compare the flexural capacity of the three kinds of post-and-core repair systems (cobalt-chromium cast post and core, zirconium oxide post andcore, and CAD/CAM-fabricated glass fiber post and core) after bypass obturation of the oval root canal warm gutta. METHODS:Ninety mandibular first premolars were selected for bypass obturation of the root canal with Obtura II & System B, and then randomized into three groups that were respectively restored with cobalt-chromium cast post and core, zirconium oxide post and core and CAD/CAM-fabricated glass fiber post and core. After that, cobalt-chromium metal crown was used for full-crown restoration. Fracture strength and fracture type were recorded in different groups. RESULTS AND CONCLUSION:The fracture resistance was higher in the cobalt-chromium cast post and core group and zirconium oxide post and core group than the glass fiber post and core group (P < 0.05), and the former two groups had no significant difference. Cobalt-chromium cast post and core was fractured at the root of tooth, and could not be repaired; the zirconium oxide post and core was fractured at the root neck and root of tooth, which was confirmed as reparative fracture; the glass fiber post and core was fractured at the tooth neck, which could be restored. These findings indicate that the cobalt-chromium cast post and core can bear greater occlusal force, but has a higher probability of root fracture; the CAD/CAM-fabricated glass fiber post and core exhibits a lower probability of root fracture