Crowns

Question 1

what is the definition of a bridge?

Answer 1

A fixed partial denture that is luted to tooth structures, primary enamel, which has been etched to provide micromechanical retention for the resin luting agent.

Question 2

what is a conventional adhesive bridgework?

Answer 2

where there is abutment placed with composite which is more aesthetic but more incasive

Question 3

what important aspects to assess before commiting to an anterior crown

Answer 3

• look at the smile line
• age (hypodontia pt’s)
• occlusion
• parafunctional habits (clinically assess toothwear, pt with high acidic diet have lower prognosis due to adhering to dentine rather than enamel)
  Option: could give pt a splint after bridge replacement
• static +dynamic occlusion: keep the pontic out of exursive movements
• occlusal features: adequate spacing

Question 4

what material are all ceramic crowns made from?

Answer 4

lithium disilicate (Emax) -> glass ceramic

Question 5

what are the general parameters of an all metal crown?

Answer 5

Occlusal
- functional: 1.5 mm
- non-functional: 1 mm
Margin: 0.5 mm

Question 6

what are the parameters of a porcelin fused metal crown?

Answer 6

Occlusal
- Functional: 2 mm
- Non-functional: 1.5 mm
Margin: 1 mm Bucally
0.5 mm palatal/lingual

Question 7

what are the different types of adhesive cement materials used for crowns?

Answer 7

• conventional luting cements
• adhesive cements
  ALWAYS FOLLOW BONDING PROTOCOL AND USE RUBBER DAM

Question 8

what are conventional luting cements used for and what are some examples?

Answer 8

used for PFM/metal (self-cure)
- resin modified GIC
- GIC
- ZOE (zinc phosphate)

Question 9

what are adhesive cements used for and what are some examples?

Answer 9

onlays
- resin based
- panavia
- veneers

Question 10

what can happen to a crown over long period of time?

Answer 10

• stain
• fracture
• worn
• leakage
• pt’s natural dentition changes

Question 11

if you are going to change a crown what are the considerations?

Answer 11

• check shade (natural daylight, no strong makeup, shade guide, teeth not overdried)
• do not shade match at the beginning (dentist eye fatigue)
• can use digital device that gives details of colour

-send photo to lab and ask technicial to weigh in.

• ask third person (e.g. nurse or pt itself)