Temporary (Provisional) Crowns Flashcards
Before cementing a permanent crown what do we usually do
We go through the temporisation phase with a temporary crown
What are the advantages of carrying out temporisation with a temporary crown before permanent cementation
- Maintain aesthetics
- Restore function
- Promote patient comfort by sealing exposed dentine
- Protect tooth vitality by sealing the exposed dentine (less plaque retentive area)
- Provides occlusal stability to prevent unwanted tooth movement
- Diagnostic potential to assess planned aesthetics or occlusal changes
- Temp crown can be used to assess tooth prognosis
- Clinical can seee if sufficient tooth toss has been removed
What can the loss or poor fitting of a temporary crown lead to
- Gingival overgrowth
- Food packing
- A difficult area for patient to effectively prevent plaque accumulation
What does the temporary crown aim to do occclusally
Maintain the occlusal and proximal contacts for positional stability
How can we use the temporary crown to assess if the permanent crown will be successful
If the temporary cotton continuously de cements or fractures this is an indication definitive crown may be unsuccessful
Which 2 routes can we take to construct our temporary crown
- Direct route with chair side techniques
2. Indirect route using the assistance of your dental lab
What can the direct route of temporary crown construction be further divided into?
- Custom made
2. Pre fabricated/ performed
What can we use to make Pre fabricated/ performed crowns
- Polycarbonate anterior
- Stainless steel posterior
- Aluminium (ion) Posterior
What do we need before we can construct a custom made temporary crown
A mould or index to be taken prior to tooth prep
Name the 3 main types of materials we can use to construct an index
- Alginate impression
- Silicone putty
- PVC Vaccuum Formed Splint
What are the benefits of alginate putty
- Quick, easy, inexpensive
2. Absorbs resin exotherm
What are he benefits of silicone putty
- Quick, easy, inexpensive
2. Durable and can be used again
When is a PVC Vaccuum Formed Splint used
When using light cured resins
When multiple temporary crowns are required or aesthetic or occlusal changes are being planned
List the stages we carry out when making and placing a custom made crown
- Take impression
- Prepare the tooth
- Place the material into the index
- Reseat the index and wait until the material hardens
- Remove index
- Trim the margins and assess occasion
- Cement
How long can it take to make a temporary crown
Can take as long as the actual preparation
Before you start making the temporary crown what should you double check
Try the index in the mouth to make sure it fully seats
Before placing material into the index what should you do
Air dry the index, prepared tooth and the adjacent areas
MOISTURE CONTROL
Why is moisture control important
It encourages the temporary crown to be removed more easily
What material are we using to make our temporary crown?
Bis acryl composite
What do we use to insert material into our index?
We use a syringe and insert the material into the deepest areas of the tooth
What do we need to take care with when placing material into the index
- Take care not to trap air especially in the incisal edges
- Make sure not to overfill the area
How can we prevent air getting trapped in the crown material
By keeping the self mixing tip in the material
After we have inserted our material into the impression what should we do
Align appropriately and fully reseat the index
Then wait until the material hardens to the gel stage before careful removing it
What do we usually need to get rid of on out temporary crown
Flat material at the crown margins
How do we get rid of flash material at the crown margins
Using a slow speed hand peice and some soflex discs
What do we need to check once we think our crown is complete
Ensure margins are well adapted and contoured
Check occlusion
Once our crown is complete made what do we do
We cement it with temporary cement
Give examples of temporary cements
Tempbond or Tempbond
What do we need to take care with when using temporary cement
Make sure not to over fill the crown with temporary cement
What can happen if we over fill the crown with temporary cement
It can be hard to fully seat the crown due to hydrostatic pressure
Once crown is seared with temporary cement what should you do
Remove any excess cement at the margins and clear the contact points
Polish the temporary crown
Why is polishing the temporary crown important
So it has a smooth shiny surface to resist plaque accumulation and staining
When taking the material out of the index what should you take care with
Take care not to damage the index when removing the temporary
Incase you need to use the index again
If we don’t have a putty index made prior to tooth preparation what can we do
We can use a technique called direct syringing
How do we carry out direct syringing
The temporary material is directly syringed around the preparation margins first and then spiralled up the axial walls
Excess is trimmed away
When assessing the margins of a temporary tooth what should we do
Look and feel with a dental probe for minor discrepancies
Why might minor discrepancies occur at the margin of a temporary crown
- Material shrinkage
- Possible distortion when the crown was removed
3, Preparation margins are slightly sub gingival
How can we correct minor marginal discrepancies
By performing remargination procedures
How do we carry out remargination
- Remove some material at the crown margin with a burr or so flex
- Apply a thin layer of scotch bond universal
- Evaporate the solvent and light cure the bond for 30 secs
- Place a small amount of composure onto the outer aspects of the provisional crown Margin where the deficiency is
- Reseat the crown and adjust composite if needed
- Remove temporary and assess whether further adjustments are required
- If all good cure composite
- Once composite cured place temporary crown and remove an flash
