Canine extensions from occlusal rests

A finger extension from the premolar rest placed on the lingual slope of the adjacent canine tooth increase the lever arm against the fulcrum line and serve as an effective indirect retainer (Figure 4-4).

Although canine extensions are placed into prepared surfaces, they are used in conjunction with occlusal rests on the mesial marginal ridge of the first premolars. This combined use significantly reduces the tipping forces on the canine teeth.

This method is particularly applicable when a first premolar must serve as a primary abutment. The distance anterior to the fulcrum line is only the distance between the mesioocclusal rest and the anterior terminal of the finger extension.