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Published byAriel Robertson Modified over 9 years ago
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TodayToday AM - Seminar - 3157AM - Seminar - 3157 – Get Casts from Marjorie – Survey Class I & II Casts (no preps) – Tripod Casts – Get Heads & Mounts ready for PM PM - ClinicPM - Clinic –Prepare guiding planes on Class I & II Typodonts (last sheet Course Sched) –Formative –Marking sheets –Diagnostic Casts Mark Sheets - Hand in AM - Seminar - 3157AM - Seminar - 3157 – Get Casts from Marjorie – Survey Class I & II Casts (no preps) – Tripod Casts – Get Heads & Mounts ready for PM PM - ClinicPM - Clinic –Prepare guiding planes on Class I & II Typodonts (last sheet Course Sched) –Formative –Marking sheets –Diagnostic Casts Mark Sheets - Hand in
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Surveying, Path of Insertion, Guiding Planes
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DefinitionsDefinitions Height of contourHeight of contour Undercut = InfrabulgeUndercut = Infrabulge SuprabulgeSuprabulge
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DefinitionsDefinitions Height of contourHeight of contour Undercut = InfrabulgeUndercut = Infrabulge SuprabulgeSuprabulge
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Rule: Retentive tip should usually be designed to be placed in the gingival 1/3
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Path of Insertion Path that the prosthesis isPath that the prosthesis is –Placed/removed –Usually a single path Path that the prosthesis isPath that the prosthesis is –Placed/removed –Usually a single path
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Advantages of a Single Path of Insertion Equalizes retentionEqualizes retention
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Advantages of a Single Path of Insertion Bracing and Cross-arch StabilizationBracing and Cross-arch Stabilization
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Advantages of a Single Path of Insertion Minimizes torque on abutmentsMinimizes torque on abutments
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Advantages of a Single Path of Insertion Allows removal without encountering interferencesAllows removal without encountering interferences
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Advantages of a Single Path of Insertion Directs forces along long axes of teethDirects forces along long axes of teeth
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Advantages of a Single Path of Insertion Provides frictional retentionProvides frictional retention
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Selecting a Single Path of Insertion Use a dental surveyor toUse a dental surveyor to –Select path –Prepare guiding planes Use a dental surveyor toUse a dental surveyor to –Select path –Prepare guiding planes
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Guiding Plane Preparation Where rigid components contact abutmentsWhere rigid components contact abutments Proximal PlatesProximal Plates Bracing ArmsBracing Arms Rigid portions of Retentive ArmsRigid portions of Retentive Arms
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Other Uses of a Surveyor Blocking out undesirable undercutsBlocking out undesirable undercuts –Ensures the framework is not cast in an undercut Blocking out undesirable undercutsBlocking out undesirable undercuts –Ensures the framework is not cast in an undercut
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Parts of a Surveyor Surveying TableSurveying Table
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Parts of a Surveyor Surveying ArmSurveying Arm
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Parts of a Surveyor Surveying ToolsSurveying Tools –Analyzing Rod Surveying ToolsSurveying Tools –Analyzing Rod
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Parts of a Surveyor Surveying ToolsSurveying Tools –Carbon Markers Surveying ToolsSurveying Tools –Carbon Markers
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Parts of a Surveyor Surveying ToolsSurveying Tools –Undercut Gauges Surveying ToolsSurveying Tools –Undercut Gauges. 01”. 03”. 02”
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Undercut Gauges
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Parts of a Surveyor Surveying ToolsSurveying Tools –Wax Trimmer Surveying ToolsSurveying Tools –Wax Trimmer
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Selecting a Path of Insertion Orient cast relatively horizontalOrient cast relatively horizontal –Final tilt rarely more than 10° from horizontal Orient cast relatively horizontalOrient cast relatively horizontal –Final tilt rarely more than 10° from horizontal
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Selecting a Path of Insertion Place analyzing rod against abutmentsPlace analyzing rod against abutments –Contact point is Height of Contour -Below is infrabulge -Above is suprabulge Place analyzing rod against abutmentsPlace analyzing rod against abutments –Contact point is Height of Contour -Below is infrabulge -Above is suprabulge
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Selecting a Path of Insertion Tilt cast to obtain maximum parallelismTilt cast to obtain maximum parallelism –Heights of contour are at relatively same position occluso-gingivally –Equal amounts of undercut Tilt cast to obtain maximum parallelismTilt cast to obtain maximum parallelism –Heights of contour are at relatively same position occluso-gingivally –Equal amounts of undercut
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Altering Path of Insertion Proximal surfaces similar undercutsProximal surfaces similar undercuts Retentive areas similar undercutsRetentive areas similar undercuts Proximal surfaces similar undercutsProximal surfaces similar undercuts Retentive areas similar undercutsRetentive areas similar undercuts
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Selecting a Path of Insertion Modify tilt if necessaryModify tilt if necessary –Soft tissue interferences Modify tilt if necessaryModify tilt if necessary –Soft tissue interferences
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Selecting a Path of Insertion Modify tilt if necessaryModify tilt if necessary –Esthetics Modify tilt if necessaryModify tilt if necessary –Esthetics
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Once Path Selected Instructor:Instructor: –Approves path –Demo: - Mark heights of contour with carbon marker -Tripod Instructor:Instructor: –Approves path –Demo: - Mark heights of contour with carbon marker -Tripod
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Selecting a Path of Insertion Lock cast position & tripodLock cast position & tripod
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TripodingTripoding
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Optimal Path of Insertion Retentive undercuts equalizedRetentive undercuts equalized –Retentive arm has a different path of escapement than guiding plane, so it must flex during removal Retentive undercuts equalizedRetentive undercuts equalized –Retentive arm has a different path of escapement than guiding plane, so it must flex during removal
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Optimal Path of Insertion Retentive undercuts equalizedRetentive undercuts equalized –Ideally, retentive arms should oppose each other on opposite sides of the arch Retentive undercuts equalizedRetentive undercuts equalized –Ideally, retentive arms should oppose each other on opposite sides of the arch
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Optimal Path of Insertion Minimize severe tooth & soft tissue interferencesMinimize severe tooth & soft tissue interferences
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Optimal Path of Insertion EstheticsEsthetics –Minimize display of clasps, metal components EstheticsEsthetics –Minimize display of clasps, metal components
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Optimal Path of Insertion Prepare Guiding PlanesPrepare Guiding Planes –Flat surfaces parallel to path of insertion –Control & limit movement of RPD –Initial contacts for RPD Prepare Guiding PlanesPrepare Guiding Planes –Flat surfaces parallel to path of insertion –Control & limit movement of RPD –Initial contacts for RPD
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Guiding Planes StabilizationStabilization
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Effectiveness of Guideplanes Most effective when:Most effective when: –Parallel to each other –More than one common axial surface Most effective when:Most effective when: –Parallel to each other –More than one common axial surface
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Effectiveness of Guideplanes Most effective when:Most effective when: –Directly opposing each other Most effective when:Most effective when: –Directly opposing each other
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Effectiveness of Guideplanes Most effective when:Most effective when: –Prepared on several teeth –Cover a large surface area Most effective when:Most effective when: –Prepared on several teeth –Cover a large surface area
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Assessing Guiding Planes Proximal View Facial View Carbon Markings
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Preparing Guiding Planes Select path of insertionSelect path of insertion Design Partial Denture *Design Partial Denture * Select number & position of guiding planesSelect number & position of guiding planes Prepare guiding planesPrepare guiding planes Select path of insertionSelect path of insertion Design Partial Denture *Design Partial Denture * Select number & position of guiding planesSelect number & position of guiding planes Prepare guiding planesPrepare guiding planes
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Use Surveyor to Align Bur Intraorally
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FINGER REST!
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BursBurs Long Cylindrical Carbide or Diamond (8837K 014)Long Cylindrical Carbide or Diamond (8837K 014) 8837K-0148837K-014
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Guiding Plane Dimensions
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Axial Surface Already Parallel to Path of Insertion NO Preparation !NO Preparation !
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Polish Prepared Surfaces Rubber wheels or pointsRubber wheels or points
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Prepare Guiding Planes First
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Effects of Guiding Planes On Retention & Stability Maintains RetentionMaintains Retention
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Effects of Guiding Planes On Retention & Stability Minimizes Need for RetentionMinimizes Need for Retention
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Effects of Guiding Planes On Retention & Stability Stabilizing TeethStabilizing Teeth
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Other Alterations of Axial Contours Lowering Heights of ContourLowering Heights of Contour –Rigid elements contacting abutments –Improve esthetics –Prepare guiding planes - most efficient method to lower Lowering Heights of ContourLowering Heights of Contour –Rigid elements contacting abutments –Improve esthetics –Prepare guiding planes - most efficient method to lower
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Other Alterations of Axial Contours Raising Heights of ContourRaising Heights of Contour –Insufficient retention in gingival 1/3 (at least 1mm from gingiva) –Prepare undercut –Add resin above to create undercut Raising Heights of ContourRaising Heights of Contour –Insufficient retention in gingival 1/3 (at least 1mm from gingiva) –Prepare undercut –Add resin above to create undercut
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Preparing Retention Axial surface must be close to parallel the path of insertionAxial surface must be close to parallel the path of insertion
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Retentive Preparation Shape Follows the path of designed retentive tipFollows the path of designed retentive tip
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Creating Undercuts with Bonded Resins Axial surface must be close to parallel the path of insertionAxial surface must be close to parallel the path of insertion
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Summary of Abutment Modifications After RPD DesignedAfter RPD Designed –Guideplanes –Lower heights of contour to eliminate interferences & improve esthetics –Create undercuts if absolutely necessary (raising heights of contour) –Rest seat preparation After RPD DesignedAfter RPD Designed –Guideplanes –Lower heights of contour to eliminate interferences & improve esthetics –Create undercuts if absolutely necessary (raising heights of contour) –Rest seat preparation
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