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DENTAL DENTAL SURVEYORSURVEYOR

The tool for perfect The tool for perfect planning of Removable planning of Removable

Partial Denture Partial Denture

Dalhousie continual educationDalhousie continual education McCracken’s Removable Prosthodontics, McCracken’s Removable Prosthodontics,

1111thth Edition Edition

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Lecture Outline

Description of Dental SurveyorDescription of Dental Surveyor Purposes of SurveyorPurposes of Surveyor Discussing some related termsDiscussing some related terms Factors That Determine Path of Placement and Factors That Determine Path of Placement and

RemovalRemoval Guiding PlanesGuiding Planes Retentive AreasRetentive Areas InterferenceInterference EstheticsEsthetics Step-by-Step Procedures in Surveying Step-by-Step Procedures in Surveying

Diagnostic CastDiagnostic Cast Recording Relation of Cast to SurveyorRecording Relation of Cast to Surveyor

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DefinitionAn 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. *

Purposes of Surveying Purposes of Surveying the Diagnostic Castthe Diagnostic Cast

1. To determine the most desirable path of 1. To determine the most desirable path of placement that will eliminate or minimize placement that will eliminate or minimize interference to placement and removalinterference to placement and removal

2. To identify proximal tooth surfaces that 2. To identify proximal tooth surfaces that are, or need to be, made parallel so that are, or need to be, made parallel so that they act as guiding planes during they act as guiding planes during placement and removal.placement and removal.

3. To locate and measure areas of the teeth 3. To locate and measure areas of the teeth that may be used for retention.that may be used for retention.

Purposes of Surveying Purposes of Surveying the Diagnostic Castthe Diagnostic Cast

4. To determine whether tooth and bony 4. To determine whether tooth and bony areas of interference will need to be areas of interference will need to be eliminated surgically or by selecting a eliminated surgically or by selecting a different path of placement.different path of placement.

5. To determine the most suitable path of 5. To determine the most suitable path of placemen that will permit locating placemen that will permit locating retainers and artificial teeth to the best retainers and artificial teeth to the best esthetic advantage.esthetic advantage.

6. To permit an accurate charting of the 6. To permit an accurate charting of the mouth preparation to be mademouth preparation to be made

Purposes of Surveying Purposes of Surveying the Diagnostic Castthe Diagnostic Cast

7. To delineate the height of contour on 7. To delineate the height of contour on abutmentabutment

teeth and to locate areas of undesirable teeth and to locate areas of undesirable toothtooth

undercut that are to be avoided, undercut that are to be avoided, eliminated, or blocked out.eliminated, or blocked out.

8. To record the cast position in relation 8. To record the cast position in relation to the selected path of placement for to the selected path of placement for future reference.future reference.

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Some Important Terms

Height of Contour Height of Contour & Undercut& Undercut

Height of Contour (HOC)Height of Contour (HOC)A line encircling a A line encircling a

tooth, tooth, designating its designating its greatest greatest circumference at circumference at a selected a selected position position determined by a determined by a dental surveyor. dental surveyor.

Height of contourHeight of contour

•Undercut Undercut ==

• InfrabulgeInfrabulge

•SuprabuSuprabulgelge

Any areas cervical Any areas cervical to HOC used for to HOC used for placement of placement of retentive retentive clasp clasp componentscomponents

Areas occlusal to Areas occlusal to the HOC used for the HOC used for the placement of the placement of nonretentive, nonretentive, stabilizing, or stabilizing, or reciprocating reciprocating componentscomponents. . **

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Non-undercut Area

Undercut here

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Types of undercuts

Tooth Undercuts *

Soft Tissues or bony Undercuts(on lingual side of ridge) #

Angle of Cervical Angle of Cervical ConvergenceConvergence

An angle viewed An angle viewed between a between a vertical rod vertical rod contacting an contacting an abutment tooth abutment tooth and the axial and the axial surface of the surface of the abutment cervical abutment cervical to the height of to the height of contour.contour.

Direct RetainersDirect Retainers

RetentionRetention Composed of:Composed of:

restrest retentive elementretentive element reciprocal (bracing) reciprocal (bracing)

elementelement minor connectorminor connector

BuccaBuccall

LinguLingualal

Rule: Retentive tip Rule: Retentive tip should usually be should usually be

designed to be placed designed to be placed in the gingival 1/3in the gingival 1/3

Path of Path of Insertion & Insertion &

RemovalRemoval

Path of InsertionPath of InsertionPath that the Path that the prosthesis is prosthesis is Placed/removedPlaced/removedUsually a single Usually a single path path

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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 Insertion (P.I)

Path of Removal (P.R)

Reverse of the Path of Insertion *

Advantages of a Single Path of Advantages of a Single Path of InsertionInsertion

Equalizes retentionEqualizes retention

Advantages of a Single Path Advantages of a Single Path of Insertionof Insertion

Bracing and Cross-arch StabilizationBracing and Cross-arch Stabilization

Advantages of a Single Path of Advantages of a Single Path of InsertionInsertion

Minimizes torque on abutmentsMinimizes torque on abutments

Advantages of a Single Path of Advantages of a Single Path of InsertionInsertion

Allows removal without Allows removal without encountering interferencesencountering interferences

Advantages of a Single Path of Advantages of a Single Path of InsertionInsertion

Directs forces along long axes of Directs forces along long axes of teethteeth

Advantages of a Single Advantages of a Single Path of InsertionPath of Insertion

Provides frictional Provides frictional retentionretention

Factors Determining Factors Determining Path of Insertion & Path of Insertion & RemovalRemoval Guiding planesGuiding planes Retentive areasRetentive areas Interference Interference EstheticsEsthetics

Guiding PlanesGuiding Planes Two or more Two or more

vertically parallel vertically parallel flat surfaces of flat surfaces of abutment teeth abutment teeth shaped to direct shaped to direct a prosthesis a prosthesis duringduring

placement and placement and removal removal **

Guiding PlanesGuiding Planes

Where rigid components contact abutmentsWhere rigid components contact abutments

• Proximal PlatesProximal Plates• Bracing ArmsBracing Arms• Rigid portions of Rigid portions of Retentive Arms Retentive Arms **

Effects of Guiding Planes Effects of Guiding Planes on Retention & Stabilityon Retention & Stability

Maintains Maintains RetentionRetention

Effects of Guiding Planes Effects of Guiding Planes On Retention & StabilityOn Retention & Stability

Minimizes Need for Minimizes Need for RetentionRetention

Guiding Planes Guiding Planes FunctionsFunctions

to ensure passage of the to ensure passage of the rigid parts of prosthesis rigid parts of prosthesis past existing areas of past existing areas of interference. interference. ##

to control & limit directions to control & limit directions of movement of RPD as it is of movement of RPD as it is being inserted, removed or being inserted, removed or while in function.while in function.

to ensure predictable clasp to ensure predictable clasp assembly function, assembly function, including retention and including retention and stabilization stabilization **

Effectiveness of Effectiveness of GuideplanesGuideplanes

Most effective Most effective when:when: Prepared on Prepared on

several teethseveral teeth Cover a large Cover a large

surface area surface area (proximal & (proximal & lingual)lingual)

Prep. Of Guiding PlanesPrep. Of Guiding Planes

Prepare Guiding Planes First *

Use Finger RestUse Finger Rest

BursBurs

Long Long Cylindrical Cylindrical Carbide or Carbide or Diamond Diamond (8837K 014)(8837K 014)

8837K-0148837K-014

Guiding Plane Guiding Plane Dimensions *Dimensions *

Round Axial Line

Angles

Round Axial Line

Angles2-4 mm 1/2-1/3 height

2-4 mm 1/2-1/3 height

Guiding Plane Guiding Plane Dimensions *Dimensions *

Use short guideplanes on Class I & II Use long guideplanes on Class III & IVUse short guideplanes on Class I & II Use long guideplanes on Class III & IV

Polish Prepared SurfacesPolish Prepared Surfaces

Rubber wheels or Rubber wheels or pointspoints

If Axial Surface Already If Axial Surface Already Parallel to Path of Parallel to Path of

Insertion?Insertion?

NO NO PreparationPreparation ! !

Retentive Retentive AreasAreas

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Retentive AreasRetentive Areas Retentive arm should Retentive arm should

have a different path of have a different path of escapement than guiding escapement than guiding plane (path of removal), plane (path of removal), so retentive arm must be so retentive arm must be forced to flex over a forced to flex over a convex surface during convex surface during placement and removal placement and removal (retention) (retention) **

Optimal Path of Optimal Path of InsertionInsertion

Retentive undercuts equalizedRetentive undercuts equalized Ideally, retentive arms should Ideally, retentive arms should

oppose each other on opposite sides oppose each other on opposite sides of the arch with fairly even of the arch with fairly even retention retention **

Retentive AreasRetentive Areas To obtain fairly even retention: To obtain fairly even retention: ----change the path of placement to change the path of placement to

increase or decrease the angle of increase or decrease the angle of cervical convergence of opposing cervical convergence of opposing retentive surfaces of abutment teeth.retentive surfaces of abutment teeth.

OROR --alter flexibility of retentive clasp arm--alter flexibility of retentive clasp arm

Optimal Path of Optimal Path of Insertion (Interference) *Insertion (Interference) *Prosthesis must be designed so that it may be Prosthesis must be designed so that it may be

placed and removed without encountering placed and removed without encountering toothtooth oror soft tissue interferencesoft tissue interference

InterferenceInterference Bony prominences and Bony prominences and

lingually inclined premolar lingually inclined premolar teeth are the most common teeth are the most common causes of interference to a causes of interference to a lingual bar connector *lingual bar connector *

InterferenceInterference If the interference is bilateral, If the interference is bilateral,

surgery or recontouring of lingual surgery or recontouring of lingual tooth surfaces, or both, may be tooth surfaces, or both, may be unavoidable.unavoidable.

If it is only unilateral, a change in If it is only unilateral, a change in the lateral tilt may prevent an area the lateral tilt may prevent an area of tooth or tissue interference.of tooth or tissue interference.

InterferenceInterferenceBony undercutsBony undercuts to remove them to remove them

surgically; surgically; to change the path to change the path

of placement at the of placement at the expense of expense of modifying or modifying or restoring teeth to restoring teeth to achieve guiding achieve guiding planes and planes and retention; retention;

to design denture to design denture bases to prevent bases to prevent such undercut areas.such undercut areas.

InterferenceInterference

Generally, interference that Generally, interference that cannot be eliminated for one cannot be eliminated for one reason or another will take reason or another will take precedence over the factors precedence over the factors of retention and guiding of retention and guiding planes.planes.

Optimal Path of Optimal Path of Insertion (Esthetics)Insertion (Esthetics)

EstheticsEsthetics Minimize Minimize

display of display of clasps, metal clasps, metal components *components *

EstheticsEsthetics

Esthetics Esthetics dictates the dictates the choice of path choice of path selected only selected only when when missing missing anterior teeth anterior teeth must be must be replaced with replaced with RPD RPD **

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Parts of a Dental Surveyor

B-Vertical Upright ColumnC-Cross Arm with Spindle HousingD-The Vertical Spindle With Tool HolderE- Screw To Lock The SpindleF- Tool adaptor HolderG- Surveying tool holderJ- Model ClampK- Model table lock nutL- Model rotating ball & socketM- Ball rotating ringN- Tool RackO- Storage CompartmentP- Model lock nut

Parts of a SurveyorParts of a Surveyor

Surveying TableSurveying Table

Parts of a Parts of a SurveyorSurveyor

Surveying ArmSurveying Arm

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Surveying Tools

3- Undercut Gauge

1- Analyzing Rods

4- Wax Trimmer

2- Carbon Marker

Parts of a SurveyorParts of a Surveyor

Surveying ToolsSurveying Tools Analyzing RodAnalyzing Rod

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Analyzing Rod

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Surveying Tools

3- Undercut Gauge

1- Analyzing Rods

4- Wax Trimmer

2- Carbon Marker

Parts of a SurveyorParts of a Surveyor

Surveying ToolsSurveying Tools Carbon MarkersCarbon Markers

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Carbon Marker

Parts of a SurveyorParts of a Surveyor

Surveying Surveying ToolsTools

Undercut GaugesUndercut Gauges

. . 01”01”

. . 03”03”

. . 02”02”

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Undercut Gauge

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Undercut Gauges

Undercut GaugesUndercut Gauges

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Undercut Gauge

Parts of a SurveyorParts of a Surveyor Surveying ToolsSurveying Tools

Wax TrimmerWax Trimmer

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Wax Trimmer

69Prof. Dr. S.Venugopal. Ney Surveyor Jelenko Surveyor

Dental Surveyor

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PROCEDURES of SURVEYING DIAGNOSTIC CAST

3- Tilt the Cast Laterally Until Equal Retentive Areas Exist on the Principal Abutments

1- Placement of the Cast2- Altering the Cast Position Anteroposteriorly

To Provide Parallel Proximal Surfaces That May Act As Guiding Planes

4- Eliminate Areas of Interference

5- Permits a More Esthetic Placement of Clasp Arms Than the Other.

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The Location of the Undercut Area Can Be Changed by Changing the Tilting

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Cast at zero tilt. Creation of undercut by tilting cast

Without guiding planes, Clasps designed are ineffective when restoration is subject to dislodging forces in

occlusal direction.

B

D

4- 4- Eliminate Eliminate Areas of InterferenceAreas of Interference by Reshaping Tooth Surfaces, by Reshaping Tooth Surfaces,

Surgery, Block-out, Restoration, or Surgery, Block-out, Restoration, or Change in lateral Tilt if Unilateral Change in lateral Tilt if Unilateral

Interference Interference

5- 5- Permits a Permits a More Esthetic More Esthetic Placement of Placement of ClaspClasp Arms Than Arms Than

the Othethe Other.r.

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A Cast in a Tilted Relationship Represents a Path of Placement Toward the Side of the Cast That Is Tilted Upward

FINAL PATH OF FINAL PATH OF PLACEMENTPLACEMENT

The anteroposterior and The anteroposterior and lateral position of the cast, in lateral position of the cast, in relation to the vertical arm of relation to the vertical arm of the surveyor that best the surveyor that best satisfies all four factors: satisfies all four factors: guiding planes, retention, guiding planes, retention, interference, and esthetics. *interference, and esthetics. *

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Tripoding is Performed While Cast is Still Mounted on the Survey Table Without Changing the Tilt to Preserve the Established Cast Tilt

Recording Relation of Cast to Surveyor *

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Tripoding the Cast *

All proposed mouth All proposed mouth changes (changes (prep. of prep. of proximal surfaces, proximal surfaces, reduction of buccal & reduction of buccal & lingual surfaces, & lingual surfaces, & prep. of rest seats) prep. of rest seats) should be indicated should be indicated on the diagnostic on the diagnostic cast in red pencil, cast in red pencil, with the exception of with the exception of restorations to be restorations to be done. *done. *

ReferencesReferences

McCracken’s Removable McCracken’s Removable Prosthodontics, 11Prosthodontics, 11thth Edition 2005 by McGivney Edition 2005 by McGivney GP, Carr AB. Chapter 11 GP, Carr AB. Chapter 11 (Surveying)(Surveying)

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