Kawagoe Y
Department of Crown & Bridge Prosthodontics, Kanagawa Dental College.
Kanagawa Shigaku. 1990 Dec;25(3):292-305.
Proper tooth preparation is one of the fundamental requirements in crown & bridge prosthodontics. However, it is difficult for students in particular to prepare adequate convergence angles of abutment tooth in the limited environment of patient's mouth. Therefore, the parallelometer was developed to improve the preparations as a supplementary device which informs the person by a signal of alarming simultaneously when a bur is not properly installed to convergence angles of abutment tooth. Sixty subjects were selected from students of Kanagawa Dental College and they were divided into two groups (A and B) to prepare abutment tooth of lower right 1st molar for full cast crown on typodont mounted into the manikin. A preliminary training was performed for once without the parallelometer for group A and with it for group B prior to a comparative experiment. The following results were obtained with primary regard to convergence angles of abutment tooth. 1. Related to each of four convergence angles, group B is superior to group A in all mean values with a statistical significance (P less than 0.01). 2. Related to a total of four convergence angles by the maximum number of subjects, group B is also superior to group A in a mean value by about ten degrees. 3. A newly developed parallelometer proved to be an efficient supplementary device for training of students to master a technique of preparation for adequate abutment tooth.
正确的牙齿预备是冠桥修复学的基本要求之一。然而，特别是对于学生来说，在患者口腔的有限环境中预备基牙的合适聚合角度是困难的。因此，开发了平行仪作为一种辅助装置来改善预备情况，当车针未正确安装到基牙聚合角度时，它会通过警报信号通知操作人员。从神奈川齿科大学的学生中选取了60名受试者，将他们分为两组（A组和B组），在安装在人体模型上的模型牙上为右下第一磨牙预备全冠的基牙。在进行对比实验之前，A组在没有平行仪的情况下进行了一次初步训练，B组则使用平行仪进行了一次初步训练。关于基牙聚合角度，得到了以下结果。1. 与四个聚合角度中的每一个相关，B组在所有平均值上均优于A组，具有统计学意义（P小于0.01）。2. 就最多受试者的四个聚合角度的总和而言，B组在平均值上也比A组高出约10度。3. 新开发的平行仪被证明是一种有效的辅助装置，可用于训练学生掌握预备合适基牙的技术。
