FP - indications and pre op assess

Question 1

what is a crown?

Answer 1

full coverage extra-coronal indirect restoration

Question 2

materials for crowns?

Answer 2

gold alloy (precious metal alloy)
ceramic
metal bonded to ceramic
non precious metal alloy (CoCr, NiCr)

Question 3

indications for crowns (7)?

Answer 3

repeated failure of direct rest.
difficulty achieving contour, contact point and occlusal contacts with direct rest.
minimise risk of tooth fracture
aesthetics
include design characteristics to accommodate metal based removable prosthesis
bridge abutment
replacement of existing crown

Question 3

2 ways restorations may fail?

Answer 3

fracture
debonding

Question 4

what types of tooth fractures are unrestorable?

Answer 4

split tooth
vertical root fracture

Question 5

what types of tooth fractures are restorable?

Answer 5

craze lines
fractured cusp
cracked tooth

Question 6

what can be added to crown prep in preparation for a denture?

Answer 6

rest seats

Question 7

describe a telescopic crown denture

Answer 7

removable denture fit precisely over teeth prepared with an ‘inner crown’
all are parallel - straight path of insertion

Question 8

when should bridges not be considered?

Answer 8

cannot justify preparing a tooth i.e., you cannot prepare a unrestored or minimally restored tooth as a bridge retainer

Question 9

what causes biological failure of a crown?

Answer 9

secondary caries
periodontal disease
gingival disease
encroachment of biologic width

Question 10

what is the measurement of the biological width?

Answer 10

3mm

Question 11

what are mechanical failures of crowns?

Answer 11

ceramic fracture
occlusal wear
cement failure

Question 12

when to not use a crown (5)?

Answer 12

no maintenance of OH
active caries/ perio disease
inadequate crown height
inadequate access for tooth prep/ imp taking
when there is a more minimally invasive option

Question 13

4 types of active disease?

Answer 13

caries
perio disease
periradicular disease
tooth wear

Question 14

what may cause inadequate access for tooth prep/ imps?

Answer 14

sclerosis - scleroderma, post radiation changes
post surgical changes

Question 15

what must be assessed prior to crown tx?

Answer 15

physical impairment - tremors, arthritis
active disease
risk of damage from occlusal dysfunction
perio tissues - prognosis of tooth
endodontic state
existing occlusal relationship

Question 16

what happens if you want to crown a non-vital tooth?

Answer 16

RCT first

Question 17

what happens if you want to place crowns but there is a reduced vertical dimension?

Answer 17

increase occlusal vertical dimension to create space