铸造核桩修复上前牙最佳直径的实验研究

Research on best diameter of incisor restored by cast post-and-core system

目的研究铸造镍铬合金核桩冠在修复上前牙时桩的最佳直径。方法对32颗离体上颌中切牙根管治疗后随机分成4组,截冠后行根管预备,嵌体蜡制做铸造镍铬合金桩冠,桩直径分别为1.10、1.50、1.70、2.00 mm。根-桩-冠黏固后,超硬石膏包埋,电子万能试验机上以135°方向静态加载,测试其断裂载荷。SAS统计软件分析结果,得出线性回归方程。Origin绘图软件描绘图形。结果载荷值随桩直径增加而增大,方程为Y=0.81239X1-0.30811;随剩余牙本质厚度降低而减小,方程为Y=-1.17298X2+6.69762(X1为桩直径、X2为剩余牙体厚度、Y为载荷值)。两方程交点位于(1.534,4.893,0.932)。结论在铸造镍铬合金核桩冠修复上颌中切牙时,桩直径1.534 mm为最佳,即载荷值、桩直径、剩余牙本质厚度三者此时形成最佳配比。

Objective To study the best diameter of the post restored in the root of maxillary central incisor by cast post-and-core system. Methods 32 human maxillary incisors extracted within three months were randomly divided into four groups, and then they were endedontically treated. We amputated the crowns of these teeth, and then restored all these teeth with Ni-Cr cast metal post-core-crown system. The diametern were 1.10, 1.50, 1.70, 2.00 mm. After that the roots were embedded with plaster and loaded on universal testing machine at a 135-degree angle to the long axis of the roots until the roots fractured. The results were statistically analyzed with SAS statistical software. Graph was drawn with Origin software. Results There was statistically significant difference of fracture loads among four groups. We found that the bigger the post＇ s diameter was, the larger the fracture load was, and the smaller the thickness of remainder dentine was, the lower the fracture load was. Conclusions The best diameter of the post restored in the root of maxillary central incisor by cast post-and-core system is 1. 534mm.