ECR- crowns and lab stages

Question 1

what is a crown

Answer 1

a restoration that is constructed outside the mouth and designed to emcompass the tooth

Question 2

what taper do we aim for with crown margins

Answer 2

6-12 degrees

Question 3

what is the buccal margin prep for FVC crowns

Answer 3

0.5mm

Question 4

what is the occlusal reduction for an FVC prep

Answer 4

1-1.5mm

Question 5

what is the lingual margin prep for an FVC

Answer 5

0.5mm

Question 6

what is the buccal margin prep for an MCC

Answer 6

1.2mm-1.5mm

Question 7

what is the occlusal reduction for the MCC

Answer 7

1.5mm - 2.5mm

Question 8

what is the lingual reduction for the mcc prep

Answer 8

0.5mm

Question 9

what is the buccal reduction for an anterior ceramic crown

Answer 9

1.0mm

Question 10

what is the occlusal reduction for ACC

Answer 10

1.5-2mm

Question 11

what is the lingual margin prep for ACC

Answer 11

1mm

Question 12

define retention

Answer 12

preventing the crown from being lifted from lateral forces

Question 13

what is resistance

Answer 13

preventing the crown from moving from horizontal forces/ rotating off

Question 14

give examples of luting cement

Answer 14

zinc phosphate

zinc carboxylate

Question 15

when might we use a core

Answer 15

little tooth structure we can build up the height using composite filling material and create an adequate taper

Question 16

advantages of FVC

Answer 16

Strong 
Similar hardness to enamel
Inert ( wont corrode) 
Minimal tooth reduction needed 
Simple manufacturing process

Question 17

disadvantages of FVC

Answer 17

Aesthetics
Very expensive
As it is inert it wont bond to tooth

Question 18

indications for FVC

Answer 18

restore function
can be use din posterior as not as important with aesthetics
teeth with less occlusal reduction

Question 19

advantages of the MCC

Answer 19

aesthetic
strong
durable

Question 20

disadvantages of the MCC

Answer 20

porcelain layer needs to be thick to hide the metal

Question 21

what are some occlusal variation option for the porcelain

Answer 21

starts on the buccal aspect
starts on the buccal aspect but extends further
porcelain extends all the way from buccal to palatal margin

Question 22

indications for MCC

Answer 22

→ Restore the function of a tooth
→ Posterior teeth when aesthetics isn’t as important( where aesthetic is a little more important than having a full gold crown eg premolars
Teeth with limited starting height- less occlusal reduction is needed than any other type of crown

Question 23

advantages of all ceramic crowns

Answer 23

Good strength

Good aesthetics