Barkhordar R A, Radke R, Abbasi J
University of California, School of Dentistry, San Francisco.
J Prosthet Dent. 1989 Jun;61(6):676-8. doi: 10.1016/s0022-3913(89)80040-x.
Fractures of restored pulpless teeth without reinforcement are a familiar dilemma to the dentist. This study examined the effect of a metal collar with approximate 3 degrees of taper on the resistance of endodontically treated roots to fracture. Teeth without copings failed at a load of 49.6 kg whereas teeth with metal collars failed at a load of 65.29 kg. Our findings indicated that reinforcement with a metal collar is necessary to enhance resistance to root fracture.
对于未经加固的已做根管治疗牙齿的骨折问题，牙医们都很熟悉这一困境。本研究检测了锥度约为3度的金属套环对经根管治疗牙根抗折性的影响。未加牙冠的牙齿在49.6千克的负荷下发生折断，而带有金属套环的牙齿在65.29千克的负荷下才发生折断。我们的研究结果表明，使用金属套环进行加固对于增强牙根抗折性是必要的。
