联合卡环、延长卡环与套筒冠固位体的基牙位移实验研究

Laboratory study on abutment movement of the combined clasp, the extension clasp and the telescopic crown

目的 探讨单侧游离端可摘局部义齿的不同固位装置对基牙的影响。方法 在上下牙列间放置食物片 ,应用单侧游离端缺失病例中使用最多的联合卡环、延长卡环和套筒冠作为固位装置。当咬合时 ,用高精度激光位移测量仪测得其基牙各自的位移量 ,进行分析比较。结果 3种不同固位装置义齿的基牙 45都有牙体移动、倾斜、扭转及垂直向的位移。其位移量在水平扭转时 ,套筒冠为最小 (P <0 0 1 ) ;而垂直向的位移 ,套筒冠则大于联合卡环和延长卡环 (P <0 0 1 )。结论 与联合卡环和延长卡环相比较 ,套筒冠所承受的咬合压力接近牙轴方向并能使基牙力分散 ,受力均匀 ,有利于基牙的健康。

Objective To study the influence of three kinds of retainers on the abutment movement of removable partial dentures (RPDs) for restoring the dentition with unilateral distal extended tooth missing. Methods The combined clasp, the extension clasp and the telescopic crown were designed to retain RPDs. When food chip was masticated between dentitions, the displacement of abutments was measured by a high sensitive laser transferring detector, and then the data was statistically analyzed. Results All of abutments showed the inclination, torsion and vertical translocation. Of them, abutments with telescopic crowns had the lowest horizontal torsion ( P < 0 01) and the highest vertical translocation ( P <0 01). Conclusions Compared with the combined clasp and the extension clasp, the telescopic crowns enable abutments to bear the load more axial and the stress to be distributed more even, so the design of the telescopic crown may be considered more favourable for the health of abutments.