桩核修复体弹性极限应力的实验研究

Evaluating the elastic limit stress of different post-core systems

目的:比较不同桩核修复体经不同粘接剂粘固后的弹性极限应力。方法:将90颗离体上前牙根管治疗后机械预备根管,使用不同粘接剂分别将铸造桩,预成桩核粘接于相应根管内,测量并记录试件发生永久形变时的载荷,同时记录各组树脂核碎裂的数量。结果:铸造镍铬桩核和预成钛桩树脂核的弹性极限应力明显高于玻璃纤维桩(P<0.05),但前二者之间无显著性差异(P>0.05)。而不同粘接剂的应用对桩核修复体弹性极限应力的影响无显著性差异。玻璃纤维预成桩的树脂核碎裂例数明显少于钛预成桩(P<0.05)。结论:不同材料桩核修复体的弹性极限应力不同;玻璃纤维桩的使用可以降低树脂核碎裂的可能性。

Objective： To compare the elastic limit stress of different post-core systems cemented with various cements in vitro. Methods：Ninety intact extracted human maxillary central incisors or canines were sectioned at the cementoenamel junction. After endodontic therapy of the root, post-holes were prepared. Three types of posts were cemented respectively with different luting cements. Each specimen was tested by a universal testing machine, and the number of core fractures was recorded for each group. Results：The elastic limit stress of cast post-core and parapost with composite core was significantly higher than that of Parapost Fiber White with composite core （ P 〈 0.05 ）, hut there was no significant difference between the elastic limit stress of cast post-core and Parapost with composite pore（ P 〉 0.05 ）. The effects of different luting cements on the elastic limit stress of different post-core systems had no significant difference（ P 〉 0.05 ）. The number of cope fracture in Parapost Fiber White group was significantly fewer than that in Parapost group（ P 〈 0.05 ）. Conclusion： Different pest-core systems significantly affect the elastic limit stress of teeth. The glass fiber pest may reduce the incidence of the core fracture.