Department of Removable Prosthodontics and Gerodontology, Tokyo Dental College, Chiba City, Chiba, Japan.
J Prosthodont Res. 2010 Apr;54(2):84-91. doi: 10.1016/j.jpor.2009.11.005. Epub 2010 Feb 8.
The purpose of this study was to evaluate the effect of differences in the retainer design on load on abutment teeth and displacement of the denture base in mandibular unilateral extension base partial removable dental prosthesis to determine the optimum design for a mechanically appropriate retainer.
Three models were used. Each incorporating a removable denture with different designs of retainer positioned. In design A, Akers clasps were positioned over the first and second premolars. In design B, embrasure clasp was positioned over the first and second premolars. In design C, rest and back-action clasps were positioned over the first and second premolars, respectively. Loading on the occlusal surface of the dentures was performed in the vertical, oblique lingual and buccal directions. Load on the abutment teeth and displacement of the denture base were determined by the three-dimensional finite element method analysis.
Vertical and buccolingual load on the abutment teeth by lingual and buccal direction loading on the denture were smaller in designs B and C than in design A. However, the superioinferior and buccolingual displacement of the denture base by buccal direction loading on the denture were largest in design A. Superioinferior and buccolingual displacement of the denture base by the lingual direction loading on the denture were largest in design C.
Under the conditions set in this study, the stability of design A was greater than that of design B or C, but load on the abutment teeth was larger.
本研究旨在评估固位体设计差异对上颌单侧延伸基托局部可摘义齿基牙受力和义齿基托位移的影响，以确定机械合适固位体的最佳设计。
使用了三个模型。每个模型都包含一个带有不同固位体设计的可摘义齿。在设计 A 中，Akers 卡环位于第一和第二前磨牙上。在设计 B 中，邻间卡环位于第一和第二前磨牙上。在设计 C 中，分别在第一和第二前磨牙上放置支托和回力卡环。在垂直、斜向舌侧和颊侧方向对义齿的咬合面进行加载。通过三维有限元法分析确定基牙受力和义齿基托位移。
义齿颊舌向加载时，基牙的垂直和颊舌向受力在设计 B 和 C 中小于设计 A。然而，义齿颊向加载时，义齿基托的上下和颊舌向位移在设计 A 中最大。义齿舌向加载时，义齿基托的上下和颊舌向位移在设计 C 中最大。
在本研究设定的条件下，设计 A 的稳定性大于设计 B 或 C，但基牙受力较大。
