1. Designing RPD’s
Surveying and MAP
Ting Ling Chang DDS
and
John Beumer III DDS, MS
Division of Advanced Prosthodontics, Biomaterials
and Hospital Dentistry
UCLA School of Dentistry
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2. Designing RPD’s
Planning sequence for RPD patients
v Diagnostic assessment and preliminary
impressions
v Diagnostic casts mounted in centric relation
v Draw the ideal RPD design (on paper)
v Transfer the design to the study casts
v Survey the study casts and determine the most
advantageous position (MAP) of the designed
RPD path of insertion and withdrawal
v Revise and finalize the RPD design

3. Designing RPD’s
Planning sequence for RPD patients
v Diagnostic assessment and preliminary
impressions
v Diagnostic casts mounted in centric relation
v Draw the ideal RPD design (on paper)
v Transfer design to the study casts
v Survey the study casts and determine the most
advantageous position (MAP) of the designed
RPD path of insertion and withdrawal
v Revise and finalize the RPD design

4. Surveying
Definition:
v Ananalysis and comparison of
the prominence of intraoral
contours (teeth and soft
tissue) associated with the
fabrication of a prosthesis
Purpose:
v Toidentify the most ideal path
of insertion and treatment
position
v Primaryobjective is to orient
the cast that positions the
teeth and associated
structures in the most
advantageous position (MAP)

5. Other Definitions
Height of contour (survey line)
v A line encircling the tooth and
designating it greatest circumference at
a selected position as determined by a
dental surveyor
Undercut (tooth)
v The portion of the surface of the tooth
which is below the height of contour in
relation to the path of insertion

6. RPD path of insertion and withdrawal
v Initial contacts on the abutment
teeth
v The RPD continuously follows the
same path guided by the proximal
plates until completely seated

7. Surveying
The most advantageous position (MAP) is determined by:
Guiding surfaces
v May be on the distal or mesial
surfaces of the tooth adjacent to the
edentulous extension areas
v Other guiding surfaces contacted by
rigid portions of the prosthesis
(minor connectors, lingual plates)

8. Surveying
The most advantageous position (MAP) is determined
by:
Retention areas
v The ideal retention area is
located in the gingival one
third of the tooth
v An given cast may present
with:
v Idealretention areas
v Lack of retention areas
v Excessive retention areas

9. Surveying
The most advantageous position (MAP) is determined
by:
Retention areas
v The ideal retention area is
located in the gingival one
third of the tooth
v An given cast may present
with:
v Idealretention areas
v Lack of retention areas
v Excessive retention areas

10. Surveying
The most advantageous position (MAP) is determined
by:
Retention areas
v The ideal retention area is
located in the gingival one
third of the tooth
v An given cast may present
with:
v Idealretention areas
v Lack of retention areas
v Excessive retention areas

11. Surveying
v Place cast on the survey table
v Insert analyzing rod (diagnostic
rod)
v Adjust the survey table to idealize
the guide planes and undercuts
Analyzing
rod

12. Surveying - Cast orientation
What is a good starting position?
Eyeball survey by placing the cast on the survey table
and standing directly over it.

13. Surveying - Cast orientation:
What is a good starting position?
v First make guiding surfaces as
parallel as possible by eye

14. Surveying - Cast orientation
v Keep the occlusal plane as close to a horizontal position
as possible.
v Path of insertion should closely follow the long axis of
the teeth

15. Surveying - Cast orientation
v Do not let one mal-positioned abutment tooth dictate
the most advantageous position (MAP)!
v We should find the MAP using majority of normal
aligned abutment teeth.

16. Surveying - Cast orientation
v Manipulate the cast position until you identify the best combination of guide
plane orientation and undercuts
v The ideal path of insertion allows seating of the prosthesis minimizing
spaces and voids

17. Analysis of Retention
v Attach the retention gauge to the surveyor
v The desired amount of retention is 0.25 mm
v The tip extends to the height of contour
v The gingival portion extends to the .25 mm (0.010”)undercut
Height of
contour
.25 mm
undercut

18. Analysis of Retention
v Attach the retention gauge to the surveyor
v The desired amount of retention is 0.25 mm
Retention gauge

19. Tooth preparation guides
v Place a blue pencil mark on the study cast to indicate areas where the
abutment teeth need to be recontoured
v In this patient an occlusal adjustment will also be necessary

20. Tooth preparation guides
v Fabricate proper guide with MAP orientation to facilitate
the mouth preparation guide planes
v Metal posts are mounted on a record base with pattern
resin to show the orientation

21. Tooth preparation guides
v Insert the preparation guide intraorally.
v Use parallel sided bur with stable finger rest to follow the
metal post orientation (MAP) for the tooth alteration
v Then the preparation for the restoration can begin

22. Analysis of Retention
v The desired amount of retention is 0.25 mm
v What do we do if reasonable contours cannot be
created?
v Full veneer crowns
Courtesy Dr. A Davodi Courtesy Dr. A Davodi

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