CSAR 16 - Provisional restorations

Question 1

Why are provisional restorations used?

Answer 1

• Aesthetics - Colour and Form
• Overeruption - ICP contact
• Tipping - Interproximal Contact Point
• Pulpal Protection - Marginal fit
• Soft tissues - Marginal fit and contour

Question 2

What are the 3 main methods of making a provisional restoration?

Answer 2

Putty matrix - from wax up/ pre op
Shell - lab made
Freehand - good result hard!

Question 3

When making a provisional restoration, how should it be in occlusion?

Answer 3

Not heavy, lighter the better so not lost

Question 4

When cementing temp bond non-eugenol what should you be aware of when placing?

Answer 4

Takes a while to set, therefore let set a bit before cementing
Need to clean inter proximal with floss or TePe brushes

Question 5

What 2 materials can be used for provisional restorations?

Answer 5

Acrylic

Bis acryl composite - less messy, e.g. quicktemp/protemp

Question 6

What are the pros and cons of bis acryl temps?

Answer 6

\+ automix 
\+ quick set
\+ low exotherm, good for pulp
\+ low shrinkage 
- harder to add to, roughen then bond and add composite 
- brittle

Question 7

What are the pros and cons of acrylic temps?

Answer 7

\+ good for long spans
\+ better flexibility 
- hand mix 
- slow set 
-/+ moderate exotherm
- high shrinkage

Question 8

When placing a temporary restoration, why is vaseline/glycerine placed over composite core prep and cured again?

Answer 8

Risk of bonding, as uncured oxygen layer remains ontop of cured compositie
Glycerine/vasline over prep again to remove oxygen inhibited layer

Question 9

What types of Zinc oxide cements are there? and when are they used?

Answer 9

When resistance and retention are satisfactory
Temp bond and temp bond non eugenol
Don’t use ZOE when composite core - can inhibit methacrylate polymerisation

Question 10

When is Zinc polycarboxylate cement used? Name one.

Answer 10

When resistance and retention are NOT satisfactory - much more adhesive but much more difficult to remove
Poly F
(temp cement)

Question 11

What are the shell techniques for a temporary restoration?

Answer 11

Standard crowns: Polycarbonate, aluminium (easy to press and correct) and stainless steel (too hard to correct)
Lab made: acrylic and composite

Question 12

How is a polycarbonate temporary crown used?

Answer 12

1) Pick shell and trim to cover preparation
2) Mix acrylic to reline -
= Bis acryl won’t stick to polycarbonate but acrylic will – ALWAYS USE ACRYLIC WHEN RELINING
3) Fill shell with acrylic & seat
4) Remove in dough stage, allow to set then polish fit and adjust occlusion

Question 13

When would no temporary be appropriate? however what may be used to cover the exposed enamel or dentine?

Answer 13

Occlusal stability - VENEERS
FV covers enamel
Zinc phosphate - prevent dentine sensitivity

Question 14

When zinc polycarboxylate and bis acryl are used what colour is produced?

Answer 14

Bright YELLOW

Question 15

How is liquid dam used as a provisional restoration? Give disadvantage.

Answer 15

Locks in undercuts and prevents tipping
Cures to tooth
Irritates gingiva as hard to clean

Question 16

What is telio onlay as a provisional restoration?

Answer 16

Jelly like acrylic material

Question 17

What options can be given when doing a temporary for a veneer?

Answer 17

• No temporisation is necessary
• May spot etch (place tiny bit of etch on enamel or bond if in dentine), hard to remove provisionals prior to bonding, but good test drive of aesthetics
• Cure composite to prep
• Essix retainer – well accepted

Question 18

What is the shrink wrap technique for a temporary restoration?

Answer 18

Causes overhangs and gingival irritation - hard to clean
Difficult to isolate/ cement crown on due to irritation
Test drive aesthetics

Question 19

In the provisional restoration shrink wrap technique why would dark staining be caused? and how can it be removed?

Answer 19

• When shrink-wrap is done, it isn’t stuck to tooth it’s just cured
• May get dark staining due to pyogenic bacteria being able to track through
• Can scale/ pumice it off