Firtell D N, Grisius R J, Muncheryan A M
J Prosthet Dent. 1985 Jan;53(1):77-82. doi: 10.1016/0022-3913(85)90071-x.
Five clasp arm designs were selected for in vitro testing of the anterior abutment of a Kennedy Class II removable partial denture. The clasps were a circumferential clasp with the cast retentive arm placed at the survey line, a circumferential clasp with a cast retentive arm placed into a mesiofacial undercut of 0.01 inch, a circumferential clasp with a wrought wire retentive arm placed into a mesiofacial undercut of 0.01 inch, a buccal I-bar placed at the greatest facial curvature into a 0.01 inch undercut, and a half T-bar buccal arm placed into a 0.01 inch distofacial undercut. The relative movement of the abutments was recorded by a polygraph on a line from a point of force in the extension and through the rest seat of the anterior abutment, 90 degrees from the first direction, and vertically in the long axis of the abutment. The amount of movement of the abutment tested varied relative to the clasp design and the directions recorded. The cast circumferential arm placed at the survey line consistently showed less movement, and a cast circumferential arm placed into an undercut showed the greatest total movement. The decision to use any of these clasp arm designs should be correlated with other clinical conditions that are present for a specific patient.
选择了五种卡环臂设计，用于对Kennedy II类可摘局部义齿的前基牙进行体外测试。这些卡环包括：一种将铸造固位臂置于观测线上的环形卡环；一种将铸造固位臂置于0.01英寸近中面部倒凹处的环形卡环；一种将锻造丝固位臂置于0.01英寸近中面部倒凹处的环形卡环；一种将颊侧I型杆置于最大面部曲度处的0.01英寸倒凹内的卡环；以及一种将半T型杆颊侧臂置于0.01英寸远中面部倒凹内的卡环。通过测谎仪记录基牙在从伸展力点沿一条线、经过前基牙的休息位、与第一方向成90度角以及沿基牙长轴垂直方向上的相对运动。所测试基牙的移动量因卡环设计和记录方向的不同而有所差异。置于观测线上的铸造环形臂始终显示出较少的移动，而置于倒凹内的铸造环形臂显示出最大的总移动量。对于特定患者，使用这些卡环臂设计中的任何一种的决定都应与其他存在的临床情况相关联。
