Heydecke G, Butz F, Strub J R
Biologic and Materials Sciences, University of Michigan, School of Dentistry, 1011 North University Avenue, Ann Arbor, MI 48109-1078, USA.
J Dent. 2001 Aug;29(6):427-33. doi: 10.1016/s0300-5712(01)00038-0.
This study compared the fracture strength and survival rate of endodontically treated crowned maxillary incisors with approximal class III cavities and different core build-ups.
Sixty-four caries free human maxillary central incisors were selected for standardized size and quality, endodontically treated and prepared with approximal cavities 3mm in diameter. Group 1 was restored with titanium posts, group 2 received zirconia posts, in group 3 the root canal was partially filled with a hybrid composite. In the control group, only the access opening was restored. All teeth were prepared for and restored with full cast metal alloy crowns and subsequently exposed to 1.2 million cycles in a computer-controlled chewing simulator with simultaneous thermocycling. In addition, the samples were loaded until fracture in a static testing device.
One specimen with composite reinforced root canal did not survive the dynamic load test. The following median fracture strengths in Newtons for the different groups were: titanium post 1038, zirconia 1057, composite resin 750, control (no post) 1171. The fracture load in group 3 (composite resin) was significantly lower (P<0.05) than in the other groups.
The reconstruction of endodontically treated single rooted teeth with approximal cavities can be successfully performed by closure of the endodontic and additional cavities with composite. Cementation of endodontic posts offers comparable but no advantageous fracture resistance. Enlargement of the root canal space after completion of endodontic treatment should be avoided and cannot be compensated for by injection of composite resin. Less catastrophic failures were observed without post reconstruction.
本研究比较了患有邻面III类洞的经根管治疗的上颌切牙采用不同桩核修复后的抗折强度和生存率。
选取64颗无龋的人上颌中切牙，使其尺寸和质量标准化，进行根管治疗并制备直径3mm的邻面洞。第1组用钛桩修复，第2组用氧化锆桩，第3组根管部分用混合复合树脂充填。对照组仅修复开髓孔。所有牙齿均制备并戴上全铸金属合金冠，随后在计算机控制的咀嚼模拟器中同时进行热循环，承受120万次循环。此外，在静态测试装置中对样本加载直至折断。
1颗采用复合树脂增强根管的样本在动态载荷测试中未存活。不同组的以下抗折强度中位数（牛顿）为：钛桩1038、氧化锆桩1057、复合树脂750、对照组（无桩）1171。第3组（复合树脂）的抗折载荷显著低于其他组（P<0.05）。
对于患有邻面洞的经根管治疗的单根牙，通过用复合树脂封闭根管和额外的洞可以成功进行修复。根管桩的粘结提供了相当的抗折性，但没有优势。根管治疗完成后应避免扩大根管空间，且不能通过注射复合树脂来弥补。未进行桩修复时观察到的灾难性失败较少。
