PCS all ceramic bridges

Question 1

Lava all-ceramic system

Answer 1

• Ceramic framework – zirconia (zirconium oxide)
• Framework designed using - CAD
• Framework milled from zirconia blanks - CAM
• Zirconia framework coloured to 7 shades
• Sintered in a high temperature furnace
• Veneered with porcelain overlay

3D shape is milled from a pre-sintered Zirconia blank using hard metal tools. The frames are milled to a larger size according to the defined sintering parameters for the zirconia charge used, that is in order to compensate for the shrinkage during the sintering process. Different frameworks can be milled automatically, even overnight

Colouring of zirconia framework before sintering (VITA® Classic) 7 shades

Question 2

colouring frameworks

Answer 2

• Chemical process
• No effect on stability
• Coloured throughout the volume
• Framework colour matched to the selected shade of the final restoration

Question 3

sintering time

Answer 3

7.5h

inc drying 11h

Question 4

after sintering need to

Answer 4

veneering with Lava Ceram (porcelain)

Question 5

preparation for all ceramic bridges

Answer 5

• 1mm – 1.5mm chamfer margins
• Rounded internal angles
• 5°-7° taper for optimal scanning and retention

Question 6

all ceramic retainers - porcelain bonded to zirconia framework

Answer 6

• Strong zirconium oxide framework requires the preparation of 1–1.5mm chamfer margins
• The preparation required for other surfaces of a tooth will depend on tooth and restoration morphology and occlusion.
• This may indicate 0.5mm for the framework and 1–1.5mm for the ‘veneering’ porcelain: a total of 2mm reduction may be required over working cusp