High strength ceramic restorations

Question 1

Ceramic is weak and must be supported HOW:

Answer 1

Resin bonded restoration: use tooth for support
PFM: use metal substructure for support
High strength ceramic for support

Question 2

High strength ceramic substructure

Answer 2

Substructure is produced by CADCAM
Slip-casting was used prior to CADCAM
Ceramics are sintered to the substructure

Question 3

Zirconia substructure materials

Answer 3

Yttrium stabilised zirconia which are machined in their ‘pre-sintered’ (soft) state
They are milled approx. 20% oversize to compensate for the shrinkage which occurs during firing
Procera, Lava Infinident, Zircon Zahn, ZR and dozens more

Question 4

Materials used

Answer 4

Zirconia is generally very opaque, however there are now some translucent versions available
Alumina (Procera) is able available for similar applications
-fewer manufactureres are fabricated at large production centres

Question 5

Glass infiltrated substructure materials

Answer 5

Inceram
Spinell
Alumina
Zirconia
-substructures are produced from blocks of lightly sintered material
-once shaped the is glass infiltrated

Question 6

Indications for glass infiltrated substructure materials

Answer 6

Spinell: translucent, not as strong, single anterior units only
Alumina: reasonably translucent, strong, single units and anterior bridges
Zirconia: very strong, bridge frameworks
-this is not yttrium stabilised zirconia

Question 7

Advantages of high strength ceramic restorations

Answer 7

Aesthetic
Very strong
Relatively simple to produce
Biocompatible
Trendy: lots of marketing and added value

Question 8

Disadvantages

Answer 8

Expensive equipment required
Confusing choice of materials and production methods
Varying strengths
Varying optical properties
Expensive: although becoming cheap

Question 9

Changing indications

Answer 9

Zirconia now being marketed for full contour restorations

This could probably support RPDs