interim restorations Flashcards by Caleb Houghton

Uses of Interim Restorations
ØEsthetics?
ØFunction?
ØSensitivity?
ØDrifting?
ØTissue Health?
ØDiagnostics?

Ø Maintain Esthetics
Ø maintain Function
Ø Prevent Sensitivity
Ø prevent Drifting
Ø maintain Tissue Health
Ø Diagnostics

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Interim Restorations
*Definition:

A prosthesis designed to enhance esthetics, stabilization
and/or function for a limited period of time after which it
is to be replaced by a definitive prosthesis.
Used to assist in determination of the therapeutic
effectiveness of a specific treatment plan or the form and
function of the planned definitive prosthesis.

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why are interim restorations essential?

Essential to Fixed Prosthodontic treatment since
restorations are fabricated indirectly in the laboratory.

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Interim Restorations
*Requirements:

*The same as for definitive restorations, except for longevity and sophistication of color.

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*Biomechanical Requirements of interim restorations
pulp? position?
occlusion?
cleaning?
margin?
strength?
retention?
esthetic/phonetics?

*Pulpal protection
*Positional stability
*Occlusal function
*Cleansability
*Marginal integrity
*Strength and retention
*Esthetics / Phonetics

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what do we protect the prepared teeth from?

*Bacterial plaque and saliva
*Exposure to irritating and painful stimuli: Temperature changes; chemicals / fluids, Marginal leakage
*Abrasion or breakage of prepared tooth surfaces

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Positional Stability of interim provided by?

*Proximal contacts
*Occlusal contacts
*Inter-abutment stability (FPD)

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positional stability of interim protheses can prevent? what if this is not done?

A provisional will prevent lateral drifting of the prepared and/or adjacent teeth)

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open prox contacts leads to?

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without proper occ contact what happens

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Restoring Masticatory Function and Occlusion
*Centric occlusal contacts?
*Lateral and protrusive guidance?
*No contact when/where?

*Centric occlusal contacts (anterior and posterior)
*Lateral and protrusive guidance where appropriate on anterior teeth.
*No contact in lateral and protrusive on posterior teeth.

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how to maintain perio health with interim restoration
margins?
contours?
texture/finish?

*Non-impinging margins
*Physiologic contours, emergence profiles, embrasures, and proximal
contact
*Smooth surface texture and finish

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Marginal Integrity
*Fit:
*Contour:
*Seal:

Marginal Integrity
*Fit: as close to finish line of tooth as possible
*Contour: smooth, undetectable with explorer; smooth surface finish
*Sealed to prevent leakage and resultant pain / caries or dislodgement
Rosenstiel
Shillingburg

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emergence profile of interim?

flat or slightly concave – NOT convex bulge

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rough or thick margins lead to?

plaque accumulation; gingival inflammation

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thickness of interim

*Adequate thickness for strength
*Withstand forces without breaking or dislodgement
*Adequate tooth reduction is necessary

*Connectors / pontic thickness

*Connectors / pontic contours ↑ w/o gingival impingement

Maintain phonetics through:

Maintain phonetics through:
*Proper tooth length, position, contours

interim fabrication using mold

While in a fluid state, the mixed
resin fills the cavity formed by a
mold, and then solidifies producing a rigid restoration.

Custom Interim – Direct Technique

Types of Interim Restorations and techniques of fabrication?

ØExternal Surface Form
*Pre-fabricated (preformed) crowns: Single crowns only
*Custom-fabricated molds: Single or multiple unit restorations

ØTechnique of fabrication
*“Direct on tooth” versus “Indirect on cast”

ØPre-fabricated Crown Forms
1) Limited to?
2) Must be lined with?
3) Considerable modification?l
4) Can manipulate resin to prevent?
5) when to use?

1) Limited to single units
2) Must be lined with auto polymerizing resin
3) Considerable modification (internal relief, axial recontouring, occlusal adjustment) may be required
4) Can manipulate resin to prevent “locking in”
5) First-visit emergency when crown is missing.

ØCustom molded crown or FPD forms:
1)time consuming?
2) Must be used for?
3) Improved?
4) Simulates?

ØCustom molded crown or FPD forms:
1) Less time consuming
2) Must be used for multiple units (FPD)
3) Improved contours and esthetics
4) Simulates planned restoration (when used in combination with
diagnostic waxing).

ØDirect Technique

ØDirect Technique
*Made intra-orally directly on patient

ØIndirect Technique

ØIndirect Technique *Made in laboratory on a cast of the prepared teeth

Direct vs. Indirect Technique advantages of each

Direct vs. Indirect Technique ØDirect Technique: 1) Convenience 2) Time required for fabrication– routine restorations ØIndirect Technique: 1) Patient comfort / allergies 2) Presence of multiple undercuts 3) Long span FPD or multiple units 4) Indirect Provisionals can be fabricated in advance of the tooth preparation appointment; use of auxiliaries

The finish and polish must contribute to? how is this done?

patient comfort and physiologic tissue health: *Tissue stabilization for esthetics *Final impression *Cementation of final restoration

Desirable Properties and Characteristics Polymer Resins for Interim Restorations 1) handling? 2) Biocompatibility? 3) Dimensional stability? 4) contouring and polishing? 5) Flexural strength and abrasion resistance? 6) Appearance? 7) Patient acceptance? 8) Chemical compatibility with?

Desirable Properties and Characteristics Polymer Resins for Interim Restorations 1) Convenient handling 2) Biocompatibility 3) Dimensional stability during polymerization 4) Ease of contouring and polishing 5) Flexural strength and abrasion resistance 6) Appearance (translucence; color; color stability) 7) Patient acceptance 8) Chemical compatibility with luting agents

Free Radical Polymerization ØUnreacted free monomer is? ØInadequate polymerization results? ØPolymerization reaction is thermal? shrinkage?

Free Radical Polymerization ØThe chemical conversion of monomer to a biologically inert polymer by chain reaction. ØUnreacted free monomer is toxic (esp. MMA) ØInadequate polymerization results in poor mechanical properties. ØPolymerization reaction is exothermic, and there is shrinkage upon polymerization and cooling.

Free Radical Polymerization process

ØInitiation *Activation: formation of a free radical by decomposition of an initiator (due to “activator”) *Benzoyl peroxide + 3o amine / heat (MMA) *Camphoroquinone + blue light-490nm (VLC composite) *Free radical combines with monomer ØPropagation (growth) *Process of adding molecules in growing chain ØTermination *Growing chains randomly combine; stop growing *Polymerization is completed

propogation

process of adding molecules in the growing chain *Physical properties of rigidity and strength develop *Setting material ↑density and exothermia, causing polymerization contraction. *↑ Temperature during propagation promotes: greater polymerization and removal of unconverted monomer

ØTermination

ØTermination *Growing chains randomly combine *Material becomes rigid – able to finish / polish (≈5 minutes) *Desirable to convert all free monomer to polymer before termination *(Does not COMPLETELY happen) *Inhibition: Reaction with eugenol, oxygen, hydroquinone will cause termination.

ØProperties associated with MONOMER: irritation? *Physical properties of? *heat/shrink? *Strength of? *As MW (size) of monomer ↑: *Composites: UDMA can affect?

*Chemical / allergic irritation *Physical properties of set material *Exothermic heat of reaction & volumetric shrinkage *Strength of mass *As MW (size) of monomer ↑: exothermia, shrinkage, and strength ↓ *Composites: UDMA can affect resilience, toughness to counteract brittleness

ØProperties associated with POLYMER (Powder): *Increase in filler content →? *Too much filler →? *Composites: size / shape of particles affects?

*Increase in filler content →Greater strength/ Less exothermia and less shrinkage *Too much filler → poor handling *Composites: size / shape of particles affects density, strength, surface finish

removal of excess provisional cement

Remove set cement with perio explorer or scaler, and then knotted floss.