Temporisation Flashcards
(31 cards)
Why do we use provisional restorations?
Prevent sensitivity, bacterial invasion, over eruption, drifting; Restore occlusion, contact points, prevent food traps, aesthetics; Assess aesthetics, occlusal scheme, response to endo/perio treatment.
What are the ideal properties of a provisional restoration?
Mechanical strength; Retention; Well fitting margins; Biocompatibility; Aesthetics; Colour stability; Easily cleaned.
What are the indications for a provisional restoration?
Intracoronal - inlays, onlays; Extracoronal - veneers, crowns, bridges.
What are the two main types of provisional restorations?
Pre fabricated; Custom made.
What is a direct provisional restoration?
Fabricated directly onto the prepared tooth.
What is an indirect provisional restoration?
Fabricated outside mouth on a plaster model.
Examples of prefabricated provisional restorations
Preformed crowns; Metal / protemp (white).
Features of polycarbonate/protemp preformed crowns
Aesthetic; Good margins if adapted correctly; Can produce contact points and occlusal contact; Relatively durable.
Disadvantages of aluminium preformed crowns
Margins can be sharp and irritant; Poor contact points; Poor aesthetics; Metallic taste.
What two things are needed for direct techniques of making temporary crowns?
Template; Self curing resin (methacrylate or bis-acryl composite).
What can be used as a template for making a temporary with the direct technique?
Silicone putty index; Alginate impression; PVC vacuum formed splint.
How to make a temporary with the direct technique
Construct template from pre op model or tooth prior to preparation; Prepare tooth; Place temp material into index; Reseat template; Trim margins and check occlusion; Cement.
What material is used for a temporary if the lab makes it (indirect)?
PMMA resins.
Advantages of a lab making a temporary
Stronger; More aesthetic; Less time trimming.
When would a direct technique be chosen?
More than 2 or 3 teeth being restored at once; Changes in occlusal/axial form; Temps needed for 3-4 weeks; Aesthetics needed.
What type of material is protemp?
Bis acryl composite.
Which material is used with 3D printing?
PMMA.
Which material is Trim?
Polyvinylethylmethacrylate.
Advantages of PMMA
Good marginal fit; Good transverse strength; Polishes well; Durability / color stability.
Disadvantages of PMMA
High exotherm; Low abrasion resistance; Free monomer may be toxic to oral tissues; High volumetric shrinkage.
Which material is not suitable for direct intraoral use?
PMMA.
Advantages of poly(vinylethylmethacrylate)
Minimal exotherm; Good abrasion resistance; Good stain resistance; Can be polished; Can be added to; Lowish shrinkage; Adequate strength; Accurate margins; Available in different shades.
Advantages of Bis-acryl composite
Adequate strength; Good marginal fit; Rapid set; Acceptable aesthetics.
Disadvantages of bis acryl composite
Granular finish; Difficult to add increments; Inferior stain resistance.
