Principles of Surveying Flashcards
Paralleling Instrument
used in RPD fabrication
DENTAL SURVEYOR
What are the leveels of undercut gages
- 01
- 02
- 03
- Survey diagnostic cast
- Contour wax patterns
- Contour ceramic & cast restorations
- Place attachments requiring parallelism
- Survey master cast
FUNCTIONS OF DENTAL SURVEYOR
What are the objectives of surveying a cast?
- Determine the most acceptable path of insertion
- Identify proximal tooth surfaces that can function as guiding planes
- Locate & measure areas of teeth that may be used for
retention - Determine if soft or bony areas of interference (undercuts) exist
- Determine most suitable path of insertion to satisfy
esthetics - Delineate height of contour on abutment teeth
- Record cast position to selected path of insertion (Tripod cast)
What is the order of the survey procedure?
- Path of Insertion Determined 2. Mark the Height of Contour/Survey Line
- Measure/Mark Retentive Undercut
- Tripod Cast
How is the path of insertion determined?
Based on Guiding Planes, Retentive Undercut, Interferences, Esthetics
The direction in which the RPD is inserted & removed from the abutment teeth.
PATH OF INSERTION
Four factos of ______ __ ______ includes:
- Guiding Planes
- Retentive Undercuts
- Interferences
- Esthetics
Path of insertion
_____ _____:
• Parallel, flattened surfaces at proximal or axial surfaces of teeth
• Contact minor connectors, guiding plates
guiding planes
t/f: the greater number of GPs = a more specific path of insertion
true
t/f: Guide planes function to increase RPD stability and retention
true
____ ____ used to identify potential
surfaces that can be converted to guiding
planes by selective grinding in occlusal 1/3-
1/2
Analyzing rod
With the anylzying rod, the Final orientation seldom - degrees from horizontal
> 10-15°
RPD mechanical retention provided by clasp that engages
_____ ______.
Resist RPD dislodging forces.
retentive undercut
_____ _____ lies between survey line and gingival margin
Undercut area
Line encircling a tooth that designates its greatest diameter at a selected position determined by a dental surveyor
HEIGHT OF CONTOUR/
SURVEY LINE
Portion of tooth above the height of contour
Suprabulge Area
- Portion of tooth below the height of contour in relation to path of insertion
- Retentive Undercut within this area
- Only Retentive clasp tips contact tooth below the Survey line
Infrabulge Area
A facial
undercut preferred: What are areas of retentive undercut:
Mesiofacial (A),
Mid-facial (B), Distofacial (C)
Mesiofacial (A),
Mid-facial (B), Distofacial (C)
Mesiolingual, Distolingual
An ideal retentive undercut lies, within_____ 1/3, at least 1mm from gingival margin
gingival
- Illusion of undercut due to excessive cast tilt
- Will not exist clinically
- Awkward path of insertion
- Patient unable to place RPD
false undercut
- Lingually-inclined mandibular teeth
- Buccally-inclined maxillary teeth
- Bony buccal exotoses, tori
- Height of contour too high, clasp placement too high
- Tissue undercut area of bar clasp
Typical Interference areas:
What are two ways that one can eliminate tooth, soft tissue, and exotoses interferences
- Alter tilt of cast/Change path of insertion
* Maintain cast tilt, eliminate by surgery or recontouring of teeth
_____ of carbon marker indicates survey line of abutment teeth
at chosen path of insertion
Side
All components (rigid) of RPD, except terminal 1/3 of retentive clasp,\_\_\_\_\_ survey line
above
Where is the ideal location of the survey line?
Ideally, survey line located at junction of middle
& gingival 1/3
Proximal 2/3 of retentive clasp & Reciprocal
clasp in middle 1/3,____ ` survey line.
above
Retentive terminal 1/3 in_____ 1/3.
gingival
If the survey line is too near the occlusal surface what can occur?
- May interfere with occlusion
- Increased leverage on tooth
- Tooth recontoured to lower survey line.
If survey line, at chosen path of insertion, too low = ?
no undercut
exists
Amount of undercut
varies depending on clasp type:
_____” for Cr-Co or Ni-Cr cast clasp
0.01”
Amount of undercut
varies depending on clasp type:
___” or____” for wrought wire clasp
0.02” or 0.03”
T/f: to correct an Inadequate Retentive Undercut one can:
– Enamoplasty to create undercut
•“Dimple”
–Addition of composite
at site to create undercut
–Surveyed crown
true
–Adjust height of vertical arm: marker touches 3 widely separate tissue surface areas
• In one plane
–Circle each tripod mark
Method One of Tripod Cast
• Draw vertical lines parallel to analyzing rod on 3 sides of cast
(Lines widely separated)
Method Two of Tripod Cast
Which method of tripoding is most often used?
Method two
Color code:
- Metal framework outline
- Wrought wire clasp
Blue
Color Code:
- Indicate retentive undercut
- Indicate tooth modification areas
- Guiding planes, Survey line reposition, Rest seat areas
Red
Color Code:
-Survey line, tripod marks and soft tissue undercuts
Black
