RPI Clasp

3D Model

The most accepted stress-releasing design described in distal extension bases is the RPI system.

Components of RPI System

• Mesio-occlusal rest on the premolar or mesiolingual surface of a canine, with the minor connector placed into the mesiolingual embrasure.

  The rest acts as a fulcrum point for the rotational movement

• Proximal plate on a distal guiding plane of the abutment tooth adjacent to the edentulous site.

  The plate is approximately 1–1.5 mm thick and extends from the marginal ridge to the junction of middle and gingival thirds.

• I-bar clasp located in the gingival third of the buccal surface.