Mouth Preparation Flashcards
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Patient Treatment
• Phase I:
(5)
– Relief of pain & infection
– Collection of diagnostic data
• Diagnostic cast, Diagnostic mounting
– Develop treatment plan
• Design RPD
– Patient education & motivation
– Occlusal equilibration
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Patient Treatment
• Phase II:
(6)
– Removal of deep caries, temporary
restorations
– Extraction of non-retainable teeth
– Preprosthetic surgery: tuberosity reduction,
etc.
– Periodontal treatment, Plaque control
– Interim prosthesis: function, esthetics
– Occlusal equilibration, may need changes
after extractions
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Patient Treatment
• Phase III:
(3)
– Definitive endodontic treatment
– Definitive restorative treatment
• Surveyed crowns, if needed
• Fixed partial dentures, if appropriate
– Occlusal plane correction
Patient Treatment
Phase IV:
– Construction RPD
Patient Treatment
• Phase V:
(3)
– Post-insertion care
– Periodic recall
– Continued plaque control
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Mouth Preparation
(9)
• Relief of pain & infection
• Caries removal
• Extractions, Preposthetic surgery
• Periodontal treatment, plaque control
• Occlusal equilibration
• Endodontics
• Definitive Restorative Treatment:
• Occlusal plane correction
• Enameloplasty for RPD
• Definitive Restorative Treatment:
(2)
– Amalgams, composites
– FPDs, crowns, surveyed crowns
Diagnostic Casts
(2)
• Preliminary design of RPD
• Identify tooth modification areas
Mouth Preparation
• Perform tooth modifications
(2)
– according to RPD diagnostic cast design
– QA Worksheet
Enamoplasty for RPD
(5)
- Develop Guide Planes
- Enlarge embrasure for minor connectors
- Lower Height of Contour
- Create undercuts if needed
- Prepare rest seats
- Develop Guide Planes
(3)
– Proximal: adjacent to edentulous areas
– ML: stress-release clasps ML minor connector
– Lingual: reciprocal clasp
- Lower Height of Contour
(3)
– Proximal 2/3 Circumferential retentive clasp
– Reciprocal clasp
– Lingual Guide Plate
- Prepare rest seats
(2)
• Occlusal
• Lingual: chevron
Guide Planes, Embrasures,
Alter Height of Contour
• Alginate Impression(s)/Snapstone Cast(s)
• Survey interim casts
• Confirm that preparations are parallel to
path of insertion in the following
sequence: (3)
• Confirm that survey line lowered
enough
- Prepare guiding planes
- Enlarge embrasures for minor
connectors - Reposition the survey line to reduce
interferences to framework placement and
enable most ideal clasp placement
- Undercut Preparation
(2)
• Used when slightly insufficient retentive
undercut
• Sloped buccal &/or lingual surface,
procedure contraindicated
– Need to reconsider other areas for
undercut or may need surveyed crown
Undercut Preparation
• Indicated:
slightly insufficient retentive
undercut with vertical buccal & lingual
surfaces
• Preparation with round-ended tapered
diamond
Rest Seat Preparations
• After adequate preparation for GP, Survey
line alterations
• Same procedure as lab projects
• Check adequacy occlusal/embrasure rest
seats:
(3)
– Patient close into beading wax
– Measure thickness of wax (Caliper)
• At least 1mm
– If unable to attain adequate depth within enamel
• Remove small amount of opposing tooth structure
– Be sure to remake impression of opposing arch
Master Cast: Class III RPD
Impression Techniques
(4)
• Residual ridge not provide RPD support
• Alginate/stock tray
• Alginate/custom tray
• Custom tray/elastomeric material
Custom tray/elastomeric material
(3)
– Preferred technique UMKC
– Not border molded
– Medium-bodied PVS
Master Cast: Extension RPD Impression
(2)
• Residual ridge important source of RPD
support
• Important to accurately record
maximum tissue support area
Broad-stress distribution concept
• Distribute occlusal forces over as many teeth &
as much soft tissue as possible
• Not overload teeth or tissue
• Increased stability & retention
• Less frequent reline
The Problem with ToothTissue Supported RPDs: (2)
The periodontal membrane allows for 0.25 +/- 0.1
mm and the muco-periosteum allows for 2.0 + mm
movement
• Due to the lever
effect of the distal
extension base,
occlusal pressure is
concentrated on the
distal end of the
base
The Solution for Tooth/Tissue
Supported RPDs
(2)
• Equalize support derived from tissue and
teeth
• To distribute load to both the natural and
artificial dentition & minimize base
movement
Master Cast: Extension RPD Impression
• Custom tray/elastomeric material
(2)
– Border-molded tray
– One-step impression
Master Cast: Extension RPD Impression
• Corrected (Altered) Cast technique
– Two-step (Dual) impression
• Step one: Impression of teeth & residual ridge
• Step two: Impression of residual ridge areas
using framework
Master Cast: Altered Cast Impression
(2)
• Step one: Impression of teeth & residual ridge
– Alginate/stock tray or
Alginate/custom tray
– Framework fabricated on 1st cast
• Framework less precise than with
elastomeric impression
• Step two: Impression of residual ridge areas
only
– Sectional trays added to framework
– Border-molded
– Elastomeric material
Master Cast: Altered/Corrected Cast
(2)
Complex technique
Prone to operator error
•Lift of distal framework during residual ridge impression
•Framework on final cast not oriented the same as in the mouth
Master Cast Impression Techniques
• Leupold, Flinton, & Pfeifer, JPD, 1992
(3)
– Compared one-step border-molded
custom tray/elastomer impression &
altered cast impression technique
– Concluded clinically insignificant difference
in the vertical displacement of final RPD
between the 2 techniques
– One-step technique less prone to operator
error than altered cast procedure
Master Cast Impression Techniques
• Frank, Brudvik, Noonan, JPD, 2004
Clinical outcome of the altered cast impression
procedure compared withuse of a one-piece cast
Compared the efficacy of an altered cast compared to a one-piece
cast with regard to base support, abutment health, and patient
comfort over time in 72 subjects.
Conclusion:
“The altered cast impression
procedure does not offer significant
advantages over the one-piece cast.”
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One-step Impression: Custom Tray
• Fabricate tray on working / diagnostic
cast
• Apply separating medium to cast
– Liquid foil (not vaseline)
• Tray extensions:
– 2-3 mm coronal to
vestibule depth in
both dentate &
edentulous areas
• Wax spacer placed over tray outline
– ~3 mm over teeth (red rope wax)
– ~1.5 mm over residual ridge (baseplate
wax
• Tray stops
– 3 widely spaced openings in wax spacer
• 3 mm openings
– Tripod support for tray
– Use teeth NOT
contacted with rests
– Residual ridge stops
similar to complete
denture tray
• Aluminum foil over wax spacer (not vaseline)
• Triad tray material adapted over foil/spacer
• Polymerize
• Add finger rests to tray surface over
edentulous areas
– Stability during impression
– Strengthen tray
• Distal tray areas prone to fracture
• Narrow, flat residual ridges
• Add handle
Custom Tray Impression
• Determine final tray extension at
impression appointment
(3)
– PIP tray flanges: extension & outer surface
– Do border molding movements
– Areas where PIP removed, shorten or thin
tray
Custom Tray Impression
• Border mold distal extension residual ridge
areas
• Elastomeric impression material
(2)
– Polysulfide: High tear strength, pour within 1 hour
– PVS: Hydrophobic, adequate tissue detail
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Master Cast
• Survey
– Determine path of insertion
• Guide planes parallel,
Equalize undercut
– Mark abutment height of contour
• Facial & Lingual
– Measure & mark retentive
undercut
• RED line
• NOT red DOT
• Approximate inferior edge of clasp
• Tripod lateral sides of cast
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Lab Prescription
(5)
• Surveyed cast
• Work authorization
– Lab RX
• Send to QA
for approval
• Send to Lab
• Framework
fabricated
