Sakaguchi R L, Borgersen S E
Department of Biomaterials and Biomechanics, Oregon Health Sciences University, Portland 97201-3097, USA.
Int J Oral Maxillofac Implants. 1995 May-Jun;10(3):295-302.
Clinical studies indicate that loosening or fracture of dental implant prostheses occurs in 5% to 45% of cases during the first year. The nature of loosening or displacement of prosthetic components is complex, since it involves cycling fatigue, oral fluids, and varied chewing patterns and loads. A finite element contact analysis method was used to study the load-transfer mechanism between prosthetic components caused by torque application to the threaded fasteners used for assembly. Screw elongation is achieved while allowing for elastic recovery of the screw to produce a clamping force on the fastened elements. Clamping forces were additive along the axis of the prosthetic components. When the gold retaining screw is fastened into the abutment screw, clamping force on the implant is increased at the expense of decreasing the clamping force at the abutment screw-abutment interface by 50%. Maximum tensile stresses in the screws after preload were less than 55% of the yield stress.
临床研究表明，在第一年中，5%至45%的牙种植体修复体出现松动或骨折。修复部件松动或移位的性质很复杂，因为它涉及循环疲劳、口腔液体以及不同的咀嚼模式和负荷。采用有限元接触分析方法来研究在用于组装的螺纹紧固件上施加扭矩时修复部件之间的载荷传递机制。在允许螺钉弹性恢复以在被紧固元件上产生夹紧力的同时实现螺钉伸长。夹紧力沿修复部件的轴线是累加的。当金固位螺钉拧入基台螺钉时，种植体上的夹紧力增加，但代价是基台螺钉与基台界面处的夹紧力降低50%。预加载后螺钉中的最大拉应力小于屈服应力的55%。
