Nishimura R D, Ochiai K T, Caputo A A, Jeong C M
Division of Advanced Prosthodontics, Biomaterials, and Hospital Dentistry, School of Dentistry, University of California, Los Angeles, Calif, USA.
J Prosthet Dent. 1999 Jun;81(6):696-703. doi: 10.1016/s0022-3913(99)70109-5.
Controversy exists regarding the connection of implants to natural teeth.
This simulation study measured photoelastically the biologic behavior of implants. Stress transfer patterns with variable implant support and simulated natural teeth through rigid and nonrigid connection were examined under simulated functional loads.
A photoelastic model of a human left mandible edentulous distal to first premolar was fabricated having 2 screw type implants (3.75x13 mm) embedded within the edentulous area. Two fixed prosthetic restorations were fabricated with either a nonsplinted proximal contact or a soldered proximal contact, and cast precision dowel attachment between implant areas and simulated tooth. Simulated vertical occlusal loads were applied at fixed locations on the restorations. Stresses, which developed in the supporting structure, were monitored photoelastically and recorded photographically.
The rigid connector in the 1 implant situation caused only slightly higher stresses in the supporting structure than the nonrigid connector. The distally loaded 1 and 2 implant-supported restoration produced the highest apical stresses, which occurred at the distal implant. The rigid connector demonstrated the greatest stress transfer in the 2 implant-supported restoration.
Lower stresses apical to the tooth or implant occurred with forces applied further from the supporting abutment. Although the least stress was observed when using a nonrigid connector, the rigid connector in particular situations caused only slightly higher stresses in the supporting structure. The rigid connector demonstrated more widespread stress transfer in the 2 implant-supported restoration. Recommendations for selection of connector design should be based on sound clinical periodontal health of a tooth and the support provided by implants.
关于种植体与天然牙的连接存在争议。
本模拟研究通过光弹性测量种植体的生物学行为。在模拟功能负荷下，研究了通过刚性和非刚性连接的可变种植体支持和模拟天然牙的应力传递模式。
制作了一个人类左下颌第一前磨牙远中无牙区的光弹性模型，在无牙区内植入2枚螺钉型种植体（3.75×13mm）。制作了两种固定修复体，一种是近端无夹板接触，另一种是焊接近端接触，并在种植体区域和模拟牙之间进行铸造精密桩核附着。在修复体的固定位置施加模拟垂直咬合负荷。通过光弹性监测支持结构中产生的应力，并进行摄影记录。
在单种植体情况下，刚性连接在支持结构中产生的应力仅比非刚性连接略高。远端加载的单种植体和双种植体支持的修复体产生的根尖应力最高，出现在远端种植体处。在双种植体支持的修复体中，刚性连接显示出最大的应力传递。
在远离支持基牙处施加力时，牙齿或种植体根尖处的应力较低。虽然使用非刚性连接时观察到的应力最小，但在特定情况下，刚性连接在支持结构中产生的应力仅略高。在双种植体支持的修复体中，刚性连接显示出更广泛的应力传递。种植体连接设计的选择建议应基于牙齿良好的临床牙周健康状况和种植体提供的支持。
