Cores/posts

Question 1

what are the purpose of a core

Answer 1

replaces missing coronal tooth structure prior to restorations with an indirect restoration to help stabilise the weakened parts of the tooth

Question 2

what is the ferrule effect

Answer 2

Question 3

what are different materials you can use for a core

Answer 3

dentine, composte, cast metal/ceramic, GI/RMGIC, Amalgam

Question 4

what are the features of a dentine core

Answer 4

• Tooth coloured
  
  • Immediate prep
  • Can be sub-gingival
  • Ideal force distrubution

Question 5

what are the features of an amalgam core

Answer 5

• Strong
  
  • Colour contrast
  • Does not bond
  • Can be used subgingival
  • Delayed preparation
  • Not good in thin sections

Question 6

what is a naayar core

Answer 6

• The pulp chamber and coronal aspect is used to create a core without a post sysem
  
  • Extending amalgam into the canal does not increase the fracture resistance of the restoration if the pulp chamber height is greater than 4mm
    Technique is outdated

Question 7

what are features of GI and RMGIC as a core material

Answer 7

• Bonds to dentine
  
  • Releases fluoride
  • Low degree thermal expansion
  • Sensitivity to moisture and long setting time
  • RMGIs improves mechanical characteristics
  • Not used often

Question 8

what are features of cast metal and ceramic as a core

Answer 8

• Strong
  
  • Colour contration
  • Does not bond
  • Two visit procedure
  • Retention is by post or telescropic crown
  • Can be subgingival
    Gold cast posts show best long term results when limited/no ferrule

Question 9

what are the features of composite as a core

Answer 9

• Bonds to tooth structure
  
  • Strong
  • Moisture sensitive
  • Immediate prep
  • Tooth coloured
  • Incremental curing and polymerisation contraction
  • Not subgingivally
    Does not need extended into the root canal system

Question 10

when should you use posts

Answer 10

severe loss of coronal tooth structure
no or minimal ferrule effect
to allow rebuilding of the tooth structure prior to crown restoration

Question 11

what is the ideal post material

Answer 11

Question 12

what is metal like as a post material

Answer 12

Question 13

what are fibre-reinforced posts like as a post material

Answer 13

Question 14

how much GP should be retained apically for post placement

Answer 14

4-5mm

Question 15

how can you create a post

Answer 15

Question 16

what are the effects of post length

Answer 16

• Longer the post the better for retention
  
  • Significant increase in clinical success if longer than the crown height
    Short posts have poor retention and transmit lateral forces to remaining root structure compared to longer posts

Question 17

what is the effect of post width

Answer 17

• Increase post length is more important than increasing diameters for improvement in post retention
  
  • Post should no exceed 1mm in diameter at its tip
  • The diameter of the post at its tip should be no greater than 1/3rd of the diameters of the root at the corresponding depth
    ○ Approx 0.6mm for lower incisors
    Approx 0.8mm posts are suitable for most teeth

Question 18

when should direct restorations be used in endodontically tx teeth

Answer 18

if intact marginal ridges
use composite (amalgam not suitable without cuspal protection)
molars without cuspal coverage are lost 6 times more

Question 19

when are indirect restorations adviced following endo

Answer 19

Question 20

what is class 0 for root filled teeth

Answer 20

Class 0: No post, composite core build up
- Enough coronal tissue to increase adhesive surface and mechanical retention
- Retain more tooth structure
Ensure occlusal relationship is carefully evaluated

Question 21

what is class I for root filled teeth

Answer 21

Class I: fibre post
- Limited coronal tissue (less than 50%)
- Two or fewer walls present in anterior teeth and premolars
- Molars: no posts except if no coronal tooth tissue and insufficient pulp chamber surface but these have poor prognosis

Question 22

what is class II for root filled teeth

Answer 22

Class II: Pre-restorative procedure needed
- Post placement can’t compensate for total or partial ferrule loss
- Anterior teeth and premolars ortho extrusion preferable
Molars surgical crown lengthening

Question 23

what is class III for root filled teeth

Answer 23

Question 24

what is class Iv for root filled teeth

Answer 24

Question 25

what are endocrowns

Answer 25

Question 26

what is a summary of the adviced restorations for all different tooth types

Answer 26