Interim restorations and protection of posterior teeth undergoing endodontic therapy

Question 1

Steps essential to success

Answer 1

1. Diagnose and remove the cause of the disease
2. Use an aseptic technique
3. Mechanically instrument the root canals to enlarge them
4. Irrigate the canals with antibacterial solutions
5. Medicate the canals with an antibacterial agent
6. Temporarily restore the tooth to avoid bacterial ingress
   during and after treatment
7. Fill the root canal system once disinfected
8. Restore the tooth to normal function

Question 2

Failure to comply with steps - subsequent infection

Continuation of?

Answer 2

Bacteria already in the tooth to survive and proliferate
New organisms to enter the tooth and establish colonies
Continuation of apical periodontitis

Question 3

Interim restoration - definition

Longevity?

Answer 3

Placed in a tooth after the previous restoration has been removed at the start of endo
Will remain in place whilst endodontic tx is being performed and after RCT has been completed until definitive restoration placed

Question 4

Temporary restoration

Answer 4

Restoration placed in endodontic access cavity

Likely to have been cut through an interim

Question 5

Interim restoration - increase chance of success because

Pathways of entry

Replacement - criteria

Answer 5

Determine how bacteria entered
Remove pathway of entry to prevent further ingress

Caries
Cracks
Exposed dentine
Broken down restoration margins

Replace with good quality sealed restoration
Assess permanent restorability and overall prognosis

Question 6

Why shouldn’t endo be undertaken through a failing/temp/poor quality restoration?

Answer 6

Easily broken into debris - blocking canals
Technique sensitive
Questionable coronal seal

Question 7

Advantages of restoring with interim restoration

Answer 7

Structural integrity to the tooth
Support for weakened cusps
Coronal seal
Rubber dam will be easy to apply, with appropriate tooth/restoration structure for the clamp to grip to
An ‘ideal’ access cavity can be cut
No risk of leakage though the coronal restoration when using irrigants
A temporary restoration will be retained better
A well restored tooth will be more comfortable and functional to the patient
The restoration can be used as a core restoration if an indirect restoration is required later

Question 8

Interim restoration - if tooth is unrestored - when does this happen

Answer 8

e.g non vital following trauma or small intra coronal restoration

Question 9

All medium/large restorations should be

Suitable materials to use

NOT suitable to use

Answer 9

Should be replaced with an appropriate interim restoration

Composite/Resin modified GIC/Amalgam

IRM/GIC

Question 10

Teeth with cracks/large restorations can be supported with

Answer 10

Metal band

Ortho or copper ring

Question 11

Metal bands help to

Answer 11

Helps to secure structure and reduce risk of cuspal fracture

Question 12

Principles of applying bands

Ensure that there are good

Answer 12

Ensure the band is the correct size for the tooth
A chemically curing cement (eg GIC or RMGIC) should
be used when luting the band
Provide good margins to allow adequate oral hygiene
Ensure the restoration works with the occlusion

Question 13

Occlusal modification and cuspal coverage restorations

Answer 13

Taking cusps out of contact and rebuild tooth using strong restorative material
Amalgam or composite

Question 14

Full coverage crowns before endo should be

Advantages of removal prior to tx

Should only be left on if?

Answer 14

Should be removed prior to commencing endo

Thorough assessment of the underlying tooth structure
Identification of hidden pathology
Better orientation when undertaking endodontic treatment
Better coronal seal

Crowns should only be left in-situ if it is certain that
there is no chance of coronal leakage or pathology
hidden under the crown

Question 15

Crown removal

Answer 15

Take sectional putty for temp Make groove through crown through to underlying tooth tissue and flip off

Question 16

Making provisional crown

Answer 16

Use temp material in putty
Ensure crown is well fitting with excellent margins
Consider Zinc phosphate
Consider sealing dentinal tubules to tackle leakage
Or use preformed metal crown adapted to fit

Question 17

Process for provisional crowns and following endo

Answer 17

Should be removed and replaced between appts and end of tx

Access cavity cut into underlying tooth should be restored with a temp restoration and not left open

Question 18

Teeth with post crowns tend to

Management

Answer 18

Leak more

Place cavit at base of post crown to improve seal
Provide NO temp post crown and restore access with an adhesive restoration such as GIC
Temp partial overdenture

Question 19

Temporary restorations - function

Ideal properties

Answer 19

Occupy access cavity between appts
Provide coronal seal in between appts

Easy to remove
Obvious difference between tooth tissue or interim restoration
Cheap

Question 20

Temporary restorations - materials

Answer 20

ZOE
GIC
RMGIC
Composite???

Question 21

Layers of temp - pulp chamber up

Answer 21

CaOH paste
Soft material e.g cavit
Sponge pellet

Question 22

Temporary material should be/not b

Answer 22

be at least 3mm in depth
not cotton wool as it ‘wicks’ bacteria into tooth
be foam/sponge pellets which are compressible

Question 23

On completion of endo tx

Answer 23

Cut GP down to ACJ
Place GIC but leave at least 3mm more coronally
Restore coronal aspect with composite or amalgam
Decide if indirect restoration required immediately