RPD Review Questions

Answer to Question #49


The correct answer is

Correct. The axis of rotation passes through the rigid metal that lies above the height of contour and closest to the edentulous space. This should be the rests, as all other rigid metal lies on inclined slopes. In the case shown, the axis of rotation would pass through the rests on teeth numbers 20 and 27.

Incorrect. The axis of rotation is not determined by the type or location of the clasps.

Incorrect. The location of the minor connectors has no relation to the axis of rotation.

Incorrect. The axis of rotation passes through the PRIMARY rests and is important when the extension base moves toward the tissues. The indirect retainers function when the extension base moves away from the tissues and are not related to the location of the axis of rotation.