RPD Manual 11 - Removable Prosthodontics - Dalhousie University

Surveying, Path of Insertion, Guiding Planes - 23
2. Place composite resin above the position of the retentive tip, using rubber dam isolation.
Place a Mylar matrix to separate the tooth from adjacent teeth. Clean the tooth with flour
of pumice, etch, apply bonding agent and place the composite with plastic instrument.
Place and contour the material as indicated below. Ensure there is adequate undercut
only in the area needed, even after polishing.
If the tooth is very
divergent from the path
of insertion, the
composite will have to be
grossly over contoured
(right), which is not
advisable for hygienic
reasons. Changing the
path of insertion or
uprighting the tooth
orthodontically may be
preferable alternatives.
3. Combination of Preparing an Undercut and Placing Composite Resin
This is most commonly done when the tooth is more divergent from the path of insertion
than usual. When possible, it is preferable to prepare retention in enamel rather than
place a resin bonded undercut. Preparation in enamel, when feasible, is less time
consuming, less expensive and probably more hygienic over an extended period of time.
Summary of Removable Partial Denture Abutment Modifications
After a path of insertion is selected and a partial denture design has been formulated, tooth
preparations are made according to the following sequence.
1. Prepare guiding planes along the path of insertion for:
a. Proximal plates
b. Bracing arms
c. Rigid portions of retentive clasps
2. Lower heights of contour to eliminate interferences and improve esthetics.
3. Raise heights of contour for retentive arm tips by preparation and/or placement of composite
resin.
4. Rest seat preparations or placement of bonded composite rest seats.