RPD Review Questions
Since tooth-supported RPDs exhibit no functional movement, the guide plates may extend above the height of contour. Extension RPDs do exhibit functional movement around an axis of rotation. The axis should pass through the rest closest to the edentulous area. However, if the guide plates next to the edentulous areas extend above the height of contour, they will pre-empt the planned rests and act like rests on inclined planes. The retentive tips would now be in front of the axis of rotation and have the potential for torquing the teeth during functional movements of the extension bases.