Transcript File - Dr.Rola Shadid

DENTAL SURVEYOR
The tool for perfect planning of
Removable Partial Denture
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
Dalhousie continual education
McCracken’s Removable Prosthodontics, 11th Edition
1
Lecture Outline
Description of Dental Surveyor
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Purposes of Surveyor
Discussing some related terms
Factors That Determine Path of Placement and Removal
Guiding Planes
Retentive Areas
Interference
Esthetics
Step-by-Step Procedures in Surveying Diagnostic Cast
Recording Relation of Cast to Surveyor
2
Definition
An instrument used to determine
the relative parallelism of two or
more surfaces of the teeth or other
parts of the cast of a dental arch. *
3
Purposes of Surveying the
Diagnostic Cast
1. To determine the most desirable path of
placement that will eliminate or minimize
interference to placement and removal
2. To identify proximal tooth surfaces that are, or
need to be, made parallel so that they act as
guiding planes during placement and removal.
3. To locate and measure areas of the teeth that
may be used for retention.
Purposes of Surveying the
Diagnostic Cast
4. To determine whether tooth and bony areas of
interference will need to be eliminated surgically
or by selecting a different path of placement.
5. To determine the most suitable path of
placemen that will permit locating retainers and
artificial teeth to the best esthetic advantage.
6. To permit an accurate charting of the mouth
preparation to be made
Purposes of Surveying the
Diagnostic Cast
7. To delineate the height of contour on abutment
teeth and to locate areas of undesirable tooth
undercut that are to be avoided, eliminated, or
blocked out.
8. To record the cast position in relation to the
selected path of placement for future reference.
Some Important
Terms
7
Height of Contour &
Undercut
Height of Contour (HOC)
A line encircling a
tooth, designating
its greatest
circumference at a
selected position
determined by a
dental surveyor.
Height
of contour
•Suprabulge
• Undercut =
• Infrabulge


Any areas cervical to
HOC used for
placement of retentive
clasp components
Areas occlusal to the
HOC used for the
placement of
nonretentive,
stabilizing, or
reciprocating
components. *
Non-undercut Area
12
Types of undercuts
Tooth Undercuts *
Soft Tissues or bony
Undercuts(on lingual
side of ridge) #
13
Angle of Cervical Convergence
An angle viewed
between a vertical
rod contacting an
abutment tooth and
the axial surface of
the abutment
cervical to the
height of contour.
Direct Retainers
Buccal
Retention
 Composed of:

 rest
 retentive
element
 reciprocal (bracing) element
 minor connector
Lingual
Rule: Retentive tip should
usually be designed to be
placed in the gingival 1/3
Path of Insertion &
Removal
Path of Insertion
Path
that the prosthesis is
Placed/removed
Usually a single path
Path of Insertion (P.I)
The Direction in Which a Restoration/
Prosthesis Moves From the Point of Initial
Contact With the Supporting Teeth to the
Terminal Resting Position Where the Occlusal
Rests Are Seated and the Denture Base Is
in Contact With the Tissue
Path of Removal (P.R)
Reverse of the Path of Insertion
*
19
Advantages of a Single Path of Insertion

Equalizes retention
Advantages of a Single Path of
Insertion

Bracing and Cross-arch Stabilization
Advantages of a Single Path of Insertion
 Minimizes
torque on abutments
Advantages of a Single Path of Insertion

Allows removal without encountering
interferences
Advantages of a Single Path of Insertion

Directs forces along long axes of teeth
Advantages of a Single Path of
Insertion
 Provides
retention
frictional
Factors Determining Path of
Insertion & Removal
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Guiding planes
Retentive areas
Interference
Esthetics
Guiding Planes

Two or more
vertically parallel
flat surfaces of
abutment teeth
shaped to direct a
prosthesis during
placement and
removal *
Guiding Planes

Where rigid components contact abutments
• Proximal Plates
• Bracing Arms
• Rigid portions of Retentive Arms *
Effects of Guiding Planes on
Retention & Stability

Maintains
Retention
Effects of Guiding Planes On
Retention & Stability
 Minimizes
Retention
Need for
Guiding Planes Functions
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to ensure passage of the rigid
parts of prosthesis past
existing areas of interference.
#
to control & limit directions of
movement of RPD as it is
being inserted, removed or
while in function.
to ensure predictable clasp
assembly function, including
retention and stabilization *
Effectiveness of Guideplanes

Most effective
when:
Prepared on
several teeth
 Cover a large
surface area
(proximal &
lingual)

Prep. Of Guiding Planes
Prepare Guiding Planes First *
Use Finger Rest
Burs

Long Cylindrical
Carbide or
Diamond
(8837K 014)
8837K-014
Guiding Plane Dimensions *
2-4
2-4 mm
mm
1/2-1/3
1/2-1/3
height
height
Round
Round
Axial
Axial Line
Line
Angles
Angles
Guiding Plane Dimensions *
Use
Use short
short guideplanes
guideplanes on
on Class
Class II &
& II
II
Use
Use long
long guideplanes
guideplanes on
on Class
Class III
III &
& IV
IV
Polish Prepared Surfaces
 Rubber
wheels or points
If Axial Surface Already Parallel to
Path of Insertion?
 NO
Preparation !
Retentive Areas
42
Retentive Areas

Retentive arm should have a
different path of
escapement than guiding
plane (path of removal), so
retentive arm must be
forced to flex over a convex
surface during placement
and removal (retention) *
Optimal Path of Insertion

Retentive undercuts equalized
 Ideally,
retentive arms should oppose
each other on opposite sides of the
arch with fairly even retention *
Retentive Areas
 To
obtain fairly even retention:
--change the path of placement to increase
or decrease the angle of cervical
convergence of opposing retentive surfaces
of abutment teeth.
OR
--alter flexibility of retentive clasp arm
Optimal Path of Insertion
(Interference) *
Prosthesis must be designed so that it may
be placed and removed without
encountering tooth or soft tissue
interference
Interference

Bony prominences and lingually
inclined premolar teeth are the most
common causes of interference to a
lingual bar connector *
Interference
If the interference is bilateral, surgery or
recontouring of lingual tooth surfaces, or
both, may be unavoidable.
If it is only unilateral, a change in the lateral
tilt may prevent an area of tooth or tissue
interference.
Interference
Bony undercuts



to remove them
surgically;
to change the path of
placement at the
expense of modifying
or restoring teeth to
achieve guiding planes
and retention;
to design denture
bases to prevent such
undercut areas.
Interference

Generally, interference that cannot be
eliminated for one reason or another
will take precedence over the factors of
retention and guiding planes.
Optimal Path of Insertion
(Esthetics)

Esthetics
 Minimize
display
of clasps, metal
components *
Esthetics

Esthetics dictates
the choice of path
selected only when
missing anterior
teeth must be
replaced with RPD
*
Parts
of a Dental Surveyor
B-Vertical Upright Column
C-Cross Arm with Spindle Housing
D-The Vertical Spindle With Tool
Holder
E- Screw To Lock The Spindle
F- Tool adaptor Holder
G- Surveying tool holder
J- Model Clamp
K- Model table lock nut
L- Model rotating ball & socket
M- Ball rotating ring
N- Tool Rack
O- Storage Compartment
P- Model lock nut
53
Parts of a Surveyor

Surveying Table
Parts of a Surveyor
 Surveying
Arm
Surveying Tools
1- Analyzing Rods
2- Carbon Marker
3- Undercut Gauge
4- Wax Trimmer
56
Parts of a Surveyor

Surveying Tools

Analyzing Rod
Analyzing Rod
58
Surveying Tools
1- Analyzing Rods
2- Carbon Marker
3- Undercut Gauge
4- Wax Trimmer
59
Parts of a Surveyor
 Surveying

Tools
Carbon Markers
Carbon Marker
61
Parts of a Surveyor
 Surveying
Tools
Undercut Gauges
. 01”
. 02”
. 03”
Undercut Gauge
63
Undercut Gauges
64
Undercut Gauges
Undercut Gauge
66
Parts of a Surveyor
 Surveying
 Wax
Tools
Trimmer
Wax Trimmer
68
Dental Surveyor
Ney Surveyor
Prof. Dr. S.Venugopal.
Jelenko Surveyor 69
PROCEDURES of SURVEYING DIAGNOSTIC
CAST
1- Placement of the Cast
2- Altering the Cast Position Anteroposteriorly
To Provide Parallel Proximal Surfaces That
May Act As Guiding Planes
3- Tilt the Cast Laterally Until Equal Retentive
Areas Exist on the Principal Abutments
4- Eliminate Areas of Interference
5- Permits a More Esthetic Placement of
Clasp Arms Than the Other.
70
The Location of the Undercut Area Can Be
Changed by Changing the Tilting
74
B
Cast at zero tilt.
Creation of undercut by tilting cast
D
Without guiding planes, Clasps designed are ineffective
when restoration is subject to dislodging forces in
occlusal direction.
75
4- Eliminate Areas of Interference
by Reshaping Tooth Surfaces,
Surgery, Block-out, Restoration, or
Change in lateral Tilt if Unilateral
Interference
5- Permits a More Esthetic
Placement of Clasp Arms Than
the Other.
A Cast in a Tilted
Relationship
Represents a
Path of
Placement
Toward the Side
of the Cast That
Is Tilted Upward
78
FINAL PATH OF
PLACEMENT
The anteroposterior and lateral
position of the cast, in relation
to the vertical arm of the
surveyor that best satisfies all
four factors: guiding planes,
retention, interference, and
esthetics. *
Recording Relation of Cast to Surveyor *
Tripoding is
Performed While
Cast is Still
Mounted on the
Survey Table
Without
Changing the Tilt
to Preserve the
Established Cast
Tilt
80
Tripoding the Cast *
81

All proposed mouth
changes (prep. of
proximal surfaces,
reduction of buccal &
lingual surfaces, & prep.
of rest seats) should be
indicated on the
diagnostic cast in red
pencil, with the
exception of
restorations to be
done. *
References


McCracken’s Removable
Prosthodontics, 11th Edition
2005 by McGivney GP, Carr
AB. Chapter 11 (Surveying)
Dalhousie continual education