Transcript Single Tooth Indirect

March 11, 2009
STI
Go for the Gold!
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Characteristics
 Parallelism
○ No undercut areas like in direct restorations
 Lost wax technique
 Higher strength than direct restorations
 Control of contours and good proximal contacts
 Ability to create acute margins: use less metal,
take away less tooth structure
 Gold casting alloy
 Multiple appointments
Considerations
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1. Biocompatibility
 Most biocompatible
 Best long lasting
 Low reactivity in oral environment
○ No emission of electrons: no corrosion
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2. High gold alloys best >75% (wt)
gold/platinum
 Lower % gold performs well
Considerations
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3. Proximal caries
 Extensive involvement
○ Casting transmits energy throughout to hold tooth
together to prevent spread of fractures
 Control of contours and contacts
 Difficult subgingival margins are more properly
restored
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4. Facial/lingual
 Caries high? Caries rate?
 Existing restorations: consider full coverage
crown
Considerations
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5. Endodontic treatment
 Consider an onlay
 Design considerations
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6. Fractured teeth
 Presence of fracture lines
 Cusp replacement
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7. Elimination of electrical or corrosive
activity
Considerations
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8. Diastema closure and occlusal plane
correction
 Need to extend mesial/distal dimension
 Correction of occlusal irregularities
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9. Removable prosthodontic abutment
 Control of rest seats and guide planes
 Partial denture forces
Considerations
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10. Economics
 More chair time needed
 Laboratory fees
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11. Age of patient
 Pulp size and anatomy
○ Example: In young patient, full gold crown requires
removal of a large amount of tooth structure. Wait until
the patient is older and pulp has receded a little bit.
 Caries rate
 Health vs. prognosis
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12. Esthetics
 Metal may be seen
 Consider alternatives: e.g. porcelain
The Inlay

Defined
 Posterior teeth
 Intracoronal = between the cusps, NOT over
cusps
○ Within the cusps (intracoronal)
 Class I or Class II (includes marginal ridge)
 May involve a cusp
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Indications
 Patient desire
 Form and function
 Removable partial denture rest seat
The Inlay Preparation
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Convenience form
 Plane cut tapered fissure burs (No. 271, No.
169L)
 Obtain uniformly tapered walls
 Smooth walls, floor, and seat
“Draw”
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Concept of Draw
 All walls must diverge from gingival to occlusal
 No undercuts
 Path of the “draw” is usually along the long axis
 10-20 degree divergence—near parallel
 10 degrees if walls are necessary short
 20 degrees if walls are long and deep
 SO: as length of wall increases, the degree of
taper should increase
Path of Draw
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The wax pattern (casting) must “draw”
from the tooth. There can be NO
undercuts or obstruction.
The Inlay: Outline form
Depth is 1.8 - 2.0 mm measured from pit
closest to the involved marginal ridge
 Maintain the bur parallel to the long axis
of the tooth at all times.
 Exception: Lower molars and
premolars with crowns tilted
lingually. Tilt bur 10 degrees to lingual.
 Maintain dentin support of uninvolved
marginal ridge

The Dovetail: Retention Form
Dovetail Retention Form
 Resists mesial/distal displacement of the
casting
 Allows casting to placed only from an
occlusal direction
 Placed even at the expense of noncarious grooves
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Proximal Box
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Maintain bur parallel to long axis
Drop bur as you would an amalgam, BUT
Buccal and lingual walls do NOT converge
toward the occlusal !!
Walls of box DIVERGE with angle of the
bur
Contacts are opened buccally and lingually
and 0.5 to 1.0 mm gingivally
NO "S" or reverse curve !
Bevels and Flares
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Bevels and Flares
 Better fit at margins
 Lesser angle metal margins are easier to finish to
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die and/or tooth
Proximal Flare - 40 degree metal margin
Placed when the restoration angle is greater that
40 degrees.
Allows a marginal enamel angle of 140 degrees
Buccal wall may be limited by esthetics
The Bevel Advantage
Gingival Bevel - 30 degree metal margin
 Casting discrepancies at the margins
are minimized
 Provide firm enamel support for margin
(no fragile)
 Placed with a GF 11 or flame-shaped
finishing bur (#7901)
 Bevels
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The Bevel Advantage
=1/2 D
Bevels
Occlusal Bevel - 40 degree metal
margin
 Provides a strong but burnishable
margin
 Not indicated if the cusp inclines are
steep so that a 40 degree angle already
will occur
 All bevels and flares should
"blend" together to allow a continuous
margin.
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The Inlay Preparation
Other Types of Casting
Types of Finish Lines
The Onlay
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Defined
 Posterior teeth
 Class II involvement
 All cusps are "capped"
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Indications
 Large defective amalgam or resin
restorations
 Weak buccal/lingual cusps that require
splinting
 Heavy occlusal wear
Other Casting Types
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Margin Requirements
 All margins should be supragingival
○ Easy to evaluate and finish the margin
○ Easier for patient to keep clean
○ No gingival irritation
 except due to:
○ Existing caries/restorations
○ Short crowns - retentive walls need 4 mm
○ Esthetics
Bottom Line
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General Principles of Partial Veneer
Castings:
 Necessity to see all surfaces
 Weak tooth is splinted
 Adequate metal - proper amount of
reduction
 Esthetics
 Smooth junctions between tooth surfaces