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Requirements of a Provisional Restoration
- • Pulpal Protection
- • Positional Stability
- • Occlusal Function
- • Easily Cleaned
- • Non-impinging Margins
- • Resistance and Retention
- • Esthetics
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Direct Custom Provisional Restorations
- • (+) Convenient (eliminates plaster cast of prepared tooth/teeth)
- • (+) Useful for “emergency” crown preparations
- • (±) Indicated for single units only (no bridges)
- • (–) Very technique sensitive
- • (–) Less accurate than indirect
- • (–) Easily distorted
- • (–) Can’t be delegated to auxiliary personnel
- • (–) Risk of locking into undercuts
- • (–) Risk of thermal or chemical irritation
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Bis-Acryl Resins
- • (+) Chemically similar to restorative composites
- – - hydrophobic resin + inorganic filler
- • (+) Low shrinkage
- • (+) Minimal heat generation
- • (+) Auto-mix delivery
- • (+) Can repair using composite
- • (–) Higher cost
- • (–) Can’t alter viscosity
- • (–) More stiff/brittle than traditional acrylics
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(Poly) Methyl Methacrylate
- • (–) Shrinkage
- • (–) Heat generation
- • (+) Auto-mix delivery
- • (+) Can repair using more PMMA or composite
- • (+) Economical
- • (+) Variable viscosity
- • (+) Less stiff than bis-acryl
- • (+) Good working time
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Adding Material to Provisionals
- • General Recommendations
- – Proximal contacts:
- • Add to provisional outside of the mouth, then seat before
- material sets
- – Margins
- • Isolate and lightly lubricate tooth and soft tissue
- • Seat provisional
- • Add material directly to margin
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Adding to Bis-acrylic (e.g. Integrity)
- – CLEAN and DRY any areas that will be added to
- • “Freshen” the surfaces with an acrylic bur
- • Apply phosphoric acid etchant for 5-10 sec, rinse/DRY
- – Apply/cure a thin layer of adhesive resin
- – Apply/cure flowable or conventional composite resin
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Adding Composite Resin to PMMA
- – Why? Esthetic modification of anterior provisionals
- • Shade change or characterization
- – Cut back labial surface of provisional with acrylic bur
- to make space for composite
- – Apply MMA monomer and dry thoroughly
- – Apply/cure adhesive resin
- – Apply/shape/cure composite resin
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Adding to PMMA to PMMA (e.g. Jet)
- – CLEAN and DRY any areas that will be added to
- • “freshen” the surfaces with an acrylic bur
- – Lightly wet the cleaned/dried surfaces with monomer
- – Add material incrementally using the brush technique
- • Dip brush in liquid, then powder, then apply to provisional
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