Department of Conservative Dentistry & Endodontics, Faculty of Dentistry, Jamia Millia Islamia, New Delhi, India.
J Prosthodont. 2012 Jun;21(4):312-6. doi: 10.1111/j.1532-849X.2011.00827.x. Epub 2012 Feb 19.
The objective of this in vitro study was to evaluate and compare the fracture resistance and fracture mode of endodontically treated teeth with wide root canals restored with various dowel methods.
Fifty human uniradicular mandibular premolar teeth were decoronated and endodontically treated. The canals were widened with diamond points. The specimens were divided into five groups on the basis of type of dowel method used: conventional custom-made cast metal dowel; single glass fiber-reinforced resin dowel; glass fiber-reinforced resin dowel with accessory fiber dowels; relined glass fiber-reinforced resin dowel; and dowels formed with the help of polyethylene fiber ribbon-reinforced resin composite. Specimens were restored with indirect composite crowns, and 150,000 cycles of cyclic loading were applied. The specimens were loaded to test the fracture resistance and fracture mode (repairable and nonrepairable).
The cast metal dowel groups had the highest fracture resistance but showed nonrepairable fracture in 90% of specimens.
Cast metal dowels had the highest fracture resistance but led to nonrepairable fracture while restoring the wide root canals under cyclic loading. Specimens restored with fiber dowels, accessory dowels, relined dowels, and ribbon-reinforced resin provided adequate fracture resistance with increased incidence of repairable fractures.
本体外研究的目的是评估和比较经根管治疗的宽根管牙的抗折能力和折裂模式，这些牙齿采用不同的嵌体修复方法进行修复。
将 50 个人类单根下颌前磨牙的牙冠部分截除并进行根管治疗。使用金刚石尖扩宽根管。根据所使用的嵌体修复方法的类型，将样本分为五组：常规定制铸造金属嵌体；单根玻璃纤维增强树脂嵌体；带有附加纤维嵌体的玻璃纤维增强树脂嵌体；重新衬里的玻璃纤维增强树脂嵌体；以及在聚乙烯纤维带增强树脂复合材料的帮助下形成的嵌体。用间接复合冠修复标本，并施加 15 万次循环加载。对标本进行加载以测试抗折能力和折裂模式（可修复和不可修复）。
铸造金属嵌体组的抗折能力最高，但 90%的标本显示不可修复性折裂。
在循环加载下修复宽根管时，铸造金属嵌体具有最高的抗折能力，但导致不可修复性折裂。用纤维嵌体、附加嵌体、重新衬里的嵌体和纤维带增强树脂修复的标本提供了足够的抗折能力，但可修复性折裂的发生率增加。
