Firtell D N, Herzberg T W, Walsh J F
J Prosthet Dent. 1979 Aug;42(2):131-4. doi: 10.1016/0022-3913(79)90161-6.
The position of a retained root for preservation of a ridge requires modification of the design of a distal-extension removable partial denture on the side of the retained root. A model with silicone rubber over the ridges and simulated retained roots was fabricated. A framework with mesial rests, distal proximal plates, and I-bar clasp arms was fitted to it. A pencil lead was attached to the framework to record the arcs of rotation of the I-bar clasp arm. The movements and the fulcrums of the prosthesis were changed by the presence of simulated retained roots posterior to the distal abutment.
为保留牙槽嵴而留存牙根的位置，需要对留存牙根一侧的远中游离可摘局部义齿设计进行修改。制作了一个覆盖牙槽嵴和模拟留存牙根的硅橡胶模型。将带有近中支托、远中邻面板和I型杆卡臂的支架安装在该模型上。在支架上连接一根铅笔芯，以记录I型杆卡臂的旋转弧。远端基牙后方存在模拟留存牙根会改变义齿的运动和支点。
