irs-t metal ceramic restorations

Question 1

What is the substructure material?

Answer 1

Bonding alloys
Precious metal alloy
NiCr or CoCr alloy

CoCr or Ti used in selective laser melting systems
Higher melting temp than metal
TEC matches ceramic
Rigid to prevent debond
Base metal to create metal oxide- wetting surface for bond

Question 2

What are advantages?

Answer 2

More aesthetic than all metal
Strong compared to all ceramic
Retainer for bridge
Can support RPD
Can incorporate attachments

Question 3

What are disadvantages?

Answer 3

Not as aesthetic as all ceramic
Technical to produce
Bond between metal/ceramic is weak
Biocompatibility concerns

Question 4

How is it produced?

Answer 4

Wax pattern converted to metal via lost wax casting
Metal surface conditioned for ceramic bond
Ceramic sintered onto metal surface

Question 5

What is the substructure design?

Answer 5

Max of 1mm ceramic on top

Produce crown to full contour
Reduce by 1mm

Inferior substructure- 0.3mm thick metal coping, ceramic thicker, weaker restoration

Metal substructure can be part of exterior-
Minimal reduction
Strong contact points
Ease of adjustment
Incorporate rest seats/milled surfaces

Question 6

What are examples of substructure design?

Answer 6

1. Occlusal and proximal contact material
2. Position of ceramic finishing edge
3. Material for margin- can be ceramic

Question 7

What is sintering?

Answer 7

Ceramic ‘Frit’ particles are packed tightly together w modelling liquid
Fired at 900C