RPD Manual 11 - Removable Prosthodontics - Dalhousie University

Framework Adjustment - 86
3. Silicone impression materials or indicating medium (e.g. Fit Checker):
These materials can also be used as three-dimensional indicators. A disadvantage
of elastic materials is that they can tear or pull off the framework. In addition,
time is required for set of the materials. In this regard the silicone fit-checking
media are more useful since they have shorter working times.
Use of Indicating Media
1. Attempt to place framework intraorally. If gross resistance to placement is felt,
remove and coat with indicating medium. If the framework seats, ask the patient
if they feel the framework pulling on any teeth. The latter sensation will be
caused by active engagement of abutment teeth. Inquire as to the overall comfort
of the framework.
2. Remove the framework and coat it with indicating medium. Align the
framework over the abutment teeth and use finger pressure over rest seats along
the path of insertion. DO NOT PLACE PRESSURE OVER GRIDWORK OF
DISTAL EXTENSIONS as this will fulcrum the framework. If gross resistance
to seating is encountered, remove and inspect for areas of burn-through. Have
an instructor inspect the framework. Relieve areas of binding as indicated.
Repeat until seating is achieved. The master cast can be inspected for areas of
abrasion that may indicate areas of gross binding as well.
3. Once the denture can be seated, coat with media and seat along the path of
insertion again. Use firm even pressure over the rest seats and or indirect
retainers. A mirror handle can be used for seating purposes. Use care in
removing the framework, as removal along the wrong path of insertion will
change the markings with displaceable media (wax & spray media).
4. Use caution in adjusting the framework. The clinician must differentiate between
normal and abnormal contacts. Guiding planes normally will exhibit long
vertical areas of contact, but broad areas of complete burn-through may indicate a
binding contact on the guiding plane. Similarly, the retentive tip of direct
retainers will normally exhibit burn-through, but active clasp retention must be
eliminated after the framework is fully seated. Therefore, the first step in
adjustment is to ensure complete seating. The most common areas that
interfere with seating are:
1. under rests
2. rigid portions of direct retainers (e.g. above the survey line)
3. interproximal portions of linguoplate major connectors
4. interproximal minor connectors
5. shoulder areas of embrasure clasps
Experience is required to differentiate between normal and excessive marking of
the indicator medium. Therefore it is wise to consult with an instructor regarding
proposed changes prior to adjustment. Adjustments can be made with small
round diamond burs, white stones or rubber abrasive points, depending on the
position and extent of binding. Do not use excessive force or the framework may