Temporisation

Question 1

What is a temporary/provisional restoration?

Answer 1

Prosthesis that is designed to enhance aesthetics, stabilisation and/or function for a limited period of time after which it is replaced with a definitive prosthesis

Question 2

What is the difference between a temporary and a transitional restoration`

Answer 2

Temporary: has a limited and predetermined life-span
Transitional: Not planned for the long-term but should serve with modifications for aesthetic, occlusal or periodontal changes for a more extensive period of time

Question 3

What is an interim restoration?

Answer 3

Used to improve aesthetics, stabilisation and protect the pulp for a limited amount of time

Question 4

What are the functions of provisional restoration?

Answer 4

Protection
Maintain tooth position - stop overeruption
Aesthetics
Diagnosis
Mastication
Facilitate plaque control
Assess tooth reduction
Informed consent - know what final one will look like
Provide coronal seal between RCT appointments
Assess/prognosis
Control/customise emergence profile

Question 5

What are the uses of provisional restorations?

Answer 5

When there is extended time between the preparation and placement of definitive restoration and there are concerns regarding tooth protection/aesthetics/occlusal/periodontal problems
Routine indirect restorations
Replacing indirect restorations
Immediate tooth replacement
Replace tooth after implant placement
Planning aesthetic occlusal, or periodontal changes prior to the definitive restoration placement

Question 6

What are the diagnostic uses of provisional restoration?

Answer 6

Aesthetic trials - confirm the tooth shape/dimensions before definitive crown
Occlusal trial - ability to tolerate new occlusion
Periodontal changes - replace overhanging restorations causing inflammation/recession or after CL surgery - use until perio tissues have stabilised

Question 7

What are the different materials can make provisional restorations from?

Answer 7

PMMA
Polyethyl methacrylate (PEM)/SNAP
Bis-acryl (composites)
Direct composites - spot etch
Preformed crowns aluminium, SS, polycarbonate 
CAD-CAM milled composites

Question 8

What are the properties of PMMA temporary restoration?

Answer 8

Good for indirect provisionals
Good aesthetics and wear resistance and strength
Easy to repair
exothermic reaction and polymerisation shrinkage
Strong smell
Free monomer can cause gingival/pulpal reactions

Question 9

What are the properties of polyethyl methacrylate/SNAP

Answer 9

Self/chemical cure
Lesser exotherm and shrinkage
Poorer aesthetics, strength wear resistance

Question 10

What are the properties of bia-acryl (composites)- pro-temp

Answer 10

Can be self/chemical or dual cure
Contains bis-GMA, TEGDMA 
Good aesthetics, better colour stability, good wear resistance
Difficult to repair
Doesn't last long

Question 11

What is a big advantage of pro-temp?

Answer 11

Get a custom fit of the crown rather than preformed which needs adjusting

Question 12

What is direct composite used for?

Answer 12

Adhesive preparations - veneers, dentine bonded to maintain occlusal contacts/improve aesthetics
Placed without bonding agent - spot etch

Question 13

What are the different preformed crowns?

Answer 13

SS, aluminium, polycarbonate

Question 14

When are preformed useful?

Answer 14

if dont have a pre-op impression

Question 15

What are the disadvantages of preformed crown?

Answer 15

Require a lot of chairside modification to be clinically acceptable

Question 16

How are CAD-CAM composites made?

Answer 16

Digital dentistry
Intra-oral scans of preparations sent to milling unit
Composite PEEK/PMMA milled and fitted
Very accurate provisionals

Question 17

What are the different temporary luting cements?

Answer 17

Zinc oxide eugenol (temp bond)
Non eugenol - (eugenol prevents setting of resin cement)
Temporary resin cements - translucent for cementing veneers and aesthetic trial
Zinc polycarboxylate cements - help unretentive provisionals

Question 18

What are the different direct techniques for provisionals? (not made in lab)

Answer 18

Preformed crowns
With use of matrices
Direct composite placement
Direct syringe

Question 19

What are the diffterent preformed crowns?

Answer 19

Come in a range of different sizes
Polycarbonate for anterior teeth
Aluminium/stainless steel - for posterior teeth

Question 20

What are the problems with preformed crowns?

Answer 20

Require trimming and crimping around the margins to provide adequate marginal coverage
Difficult to assess margin adaptation interproximally may need a lot of adjustments

Question 21

How do you fit a stainless steel preformed crown?

Answer 21

Choose suitable size
Trim and crimp margins to improve seating
Can be relined with PMMA/PEM/Bis-acryl to improve fit
Check occlusion
Cement into place
Remove excess

Question 22

What is different about fitting polycarbonate preformed crowns?

Answer 22

Can also shape to improve appearance

Question 23

How do you take provisionals from matrices?

Answer 23

Pre-op impression in silicone or alginate
Can also take impression of a wax-up of the tooth or use it as an essix retainer/suck-down matrix
If seated correctly then needs minimal adustments

Question 24

What is the difference with using alginate or silicone when taking pre-op impression

Answer 24

Alginate: cheap, dissipates exotherm better
Silicone: more expensive, re-usable - can give to patient to replace temp if need to

Question 25

How do you use a wax up?

Answer 25

Ask lab to build up the study model with wax and take an impression - get the matrix from this
Used if have a broken down tooth

Question 26

How do you make a provisional from matrices?

Answer 26

Coat with vaseline - allows easy removal
Use Bis-Acryl (pro-temp) placed into the impression and then seated onto prep, remove at the rubbery stage before locks into undercuts
Adjust margins and finish/polish
Use soflex to adjust

Question 27

What is the spot-etch technique?

Answer 27

Use of phosphoric acid etch at one spot in the centre of the tooth (rinse/dry) and then directly applying bulk of composite without bonding agent
Easily remove with probe if need to

Question 28

How can malleable composites be used?

Answer 28

Easier handling allows them to be moulded over the tooth then light cured

Question 29

When are the direct composite techniques used?

Answer 29

Adhesive preps where there is minimal tooth reduction
Veneer preps
Gold onlay
Resin-bonded bridge preps

Question 30

What is the direct syringe technique and when is it used?

Answer 30

Last resort if matrix doesnt fit or dont have access to preformed crowns
Material placed around the tooth, starting at margins
PMMA/PEM easier than Bis-Acryl as slumps less

Question 31

How are indirect provisionals made?

Answer 31

Made before the crown prep appointment by taking imps for study models
Some initial reduction can be done on the model and then some provisionals made, these are relined chairside to fit the preps

Question 32

when would you not need a provisional?

Answer 32

preps in enamel on non-occluding surfaces
Quick lab turn-over time
Use of CAD-CAM in office milled restorations - make on same day and cement on same day

Question 33

What are the options if provisional is always breaking?

Answer 33

Relieve inside of the pre-op imp to increase bulk of provisional material then trim back chairside
Or make the prep less minimal and put protemp inside the temp and reapply to tooth

Question 34

What can you do if have marginal gaps on the provisional?

Answer 34

Reline/repair provisional ensure adequate adaptations of pre-op imp by placing silicone around the necks of the teeth and in tray
Can also use light bodied on the tooth and putty in the tray to improve accuracy