CSAR 1+2 - Intro to CSAR Flashcards
What classifies a tooth to have an extra coronal restoration?
At least one cusp is replaced
Where is the crack normally in crack cusp syndrome?
Dentine
What are the disadvantages of crowns?
Weaken tooth
Potential for pulpal damage
Failure
Expensive
What are the differences of the ceramics 1. EMax and 2. Zirconia?
Both strong and white
- Can be etched therefore bonded
- Can’t be etched therefore not predictable bonding, however stronger
What is mechanical cementation of crown? Give material example.
Conventional cement - Zinc phosphate/GIC
Cement acts as filler, no bond
What is adhesive cementation of crown?
Resin cement - bonded
What structure of the tooth is best for adhesive cementation?
Enamel bone is more stable, dentine bond decreases over time
When a crown is placed on an anterior tooth, what forces occur?
Compression buccally and tension palatally
What force do you want to avoid when restoring teeth?
AVOID FELXION
What happens to the force on a tooth once the marginal ridge is lost?
Increases flexion
What crown preparation is made to provide mechanical retention for restoration?
Occlusal reduction
Axial reduction
Marginal configuration
What does cuspal reduction and coverage do to the forces applied to a posterior tooth?
Stops tensile loading on the cusps, which can form cracks
Results in compressive load over the tooth, stabilising the tooth
What are the advantages and disadvantages of not crown prepping a tooth fully coronally when using adhesive retention?
++ A lot of tooth tissue is left and do not need to taper the prep to form retention
– Mechanical adhesion compromised
What should be considered when thinking is this tooth restorable?
Ability to retain core Isolation Ferrule to retain restoration Retention/resistance form Cold sensitivity >> electric pulp tester
Why would a crown preparation result in loss of vitality?
Pulp damage during preparation
Dentine exposure - bacteria enters tooth
