Provisional Extra-Coronal Restorations

Question 1

what is a provisional extra-coronal restoration?

Answer 1

a temporary restoration is placed outside the tooth’s crown to provide protection & stability until a permanent restoration is placed (might be waiting on lab manufacturing it, soft tissue healing etc)

Question 2

what are required characteristics for a provisional restoration?

Answer 2

to fix/restore the following:

• tooth preparation (degrades tooth function, compromises aesthetics in smile line)
• occlusal & interproximal reduction (exposed dentine)
• have good margins, well contoured
• easy to clean by the patient
• prevent sensitivity

Question 3

what are the desirable characteristics of provisional materials?

Answer 3

• non irritant (pulp, periodontal tissues)
• low temperature rise during setting
• dimensionally stable
• adequate working & setting time,
• strength & wear resistance
• good aesthetics

Question 4

what are the types of provisional restorations?

Answer 4

• Custom formed (preferable but technically demanding)
• Preformed (adjust to fit chaarside)

Question 5

what is an Iwanson gauge/caliper?

Answer 5

Used to measure the size of teeth/crowns or other tissues in the oral cavity

Question 6

what are the steps for making a custom RESIN provisional crown?

Answer 6

1. sectional impression
2. prep the chosen tooth
3. syringe bis-acrylic comp resin onto mixing pad
4. syringe the mixed material into sectional impression of tooth that has been prepared
5. relocate impression in the mouth
6. remove before complete polymerisation
7. using high speed/polishing discs, clear up any excess around borders
8. confirm tooth prep
9. check marginal fit & occlusion
10. check aesthetics
11. cement the provisional using a temporary luting agent

Question 7

what are the 2 main variations of preformed provisional crowns?

Answer 7

• tooth colored
• preformed metal crowns

Question 8

what are problems with preformed provisional crowns?

Answer 8

• unlike to fit accurately
• large bank of crowns needed since variations between patients (costly)

Question 9

when are preformed provisional crowns useful?

Answer 9

when NO IMPRESSION prior to tooth prep/damage is taken

• trauma cases

Question 10

what are the stages of adding a preformed provisional crown? [Anterior tooth] (Shell Crown)

Answer 10

1. select shell slightly larger than the prep
2. trim back crown until fits
3. fill shell
4. seat over the tooth
5. allow polymerisation
6. remove
7. check fit and contacts
8. Trim/tidy borders if needed
9. cement with temporary luting cement (Tempbond)
10. make sure gingivae is NOT BLANCHING when crown put on (too tight)