Temporisation Flashcards
What is a provisional restoration?
A prosthesis that is designed to enhance aesthetics, stabilisation and/or function for a limited period of time, after which it is to be replaced by definitive prosthesis
Function of provisional?
Protect and maintain tooth position Aesthetic Facilitate plaque control Provide coronal seal Space maintenance
How can temporaries be used as diagnostic tool?
- Aesthetic - confirm shape, dimensions
- Occlusal - can pt tolerate
- Periodontal change - can keep in place until tissue stabilised
Diff between temporary and transitional?
Temporary - limited and predetermined life span
Transitional -not planned for long term but can serve a more extensive period of time
When could PMMA be used as temp?
Good indirect provisionals
Good aesthetic, strength and wear resistance
Disadv: can’t be used intra-oral as significant exothermic reaction
Polymerisation shrinkage
Cause pulp/gingival reactions
When could PEM be used and give example?
SNAP - polyethyl methacrylate
Used to reline directa crowns
Less exothermic and p.shrink
Poorer aesthetic, strength and wear resistance
When/why would Bis-Acryl materials be used?
Good aesthetic, better colour stability, good wear resistance in adequate thickness
Weak thin reactions, difficult to repair
Example: ProTemp
When/ why would resin composites be used?
Used mainly in adhesive preparations to maintain occlusal contacts/ aesthetics
Placed w/o bonding (spot-etch)
When would preformed crowns be used as temp?
Useful when don’t have pre-op impression or crown very broken down
Difficult to control marginal adaptation - require significant chair side modification
Can technology be used to provide provisionals?
Yes, CAD-CAM milled composites can be used via intra-oral scanners
Make very accurate provisionals
What cement can be used with preformed temporary?
Temporary luting cement e.g TempBond (ZoE)
When should Temp Bond NE be used?
ZoE free temp bond
Useful is using a resin-based luting cement as eugenol can inhibit polymerisation of uncured resin
What is the basic information to know about preformed crowns?
Come in range of sizes White - polycarbonate for anterior Aluminium/ SS for posterior Require trim/ crimping as margin - difficult to assess interproximally Can be relined to resin to improve fit
How should polycarbonate crowns be used?
E.g Directa
Choose suitable size, trim margin if needed
Reline w/ PEM and trim excess
Check occlusion and cement
How can matrices be used?
Pre-op impression in silicone or alginate
If seated carefully require minimal adjustment
Need to coat tooth w/ Vaseline
Why use alginate or silicone for matrices?
Alginate- cheap
Silicone- expensive, re-usable, more stable, pt can take index if needed for emergency appt
What material is often used w/ matrices?
ProTemp - BisAcryl
Placed into imp and seated
Remove at rubbery stage as can lock into undercut
Adjust margins and finish
How can composite be used directly as temporary?
Used adhesive prep w/ minimal tooth reduction
Use malleable composite: easier handling allows them to be moulded over tooth and light cured
What is spot-etch technique?
Use of phosphoric acid in one spot centre of tooth - rinsed and dried
Then apply bulk composite w/o bonding agent
Can be removed easily w/ probe when required
When could direct syringe method be used?
Last resort if matrix doesn’t fit or don’t have access preformed crown
Material placed around tooth starting at margin
PMMA/PEM > Bis-Acryl
What is an indirect provisional?
Can be made before crown prep appt by taking impression for model
Relined chair side to fit prep
When would no provisional be used?
Preparation just in enamel
Prep not on occluding surface
What to do if provisional always breaking?
Could be a very minimal prep
Reline inside pre-op impression to increase bulk on provisional material then trim
What to do if have marginal gaps w/ temporary?
Reline/ repair provisional
Ensure adequate adaptation of pre-op imp
Place silicone around necks of teeth and in tray
Improve accuracy - light bodies silicone on tooth and putty in tray
