digital all ceramic Flashcards
(20 cards)
what materials are used in the digital workflow?
zirconia
lithium disilicate
feldspathic ceramic
what is zirconia used for
Crowns and bridges due to strength and durability
how is zirconia processed?
dry milled
presentation of zirconia - 2
Pre-shaded zirconia block - uniform colour, consistent
Multilayer zirconia block - gradient shading, aesthetic, maintains strength and durability
remember
processing steps for zirconia
-CAD design
-Zirconia is dry milled - 50-90MPa
-Excess material is removed
-Sintering in a vacuum furnace 7hrs, 1400-1600c temp
-Polishing or staining and glazing
-Stain and glazed has better aesthetics
what is lithium disilicate used for?
Anterior crowns and veneers due to translucency and strength
remember
lithium disilicate has a variety of shades and translucencies but doesn’t affect the strength
compare lithium disilicate to zirconia and metal
Less resistant to flexural bending than zirconia and metal
name a lithium disilicate used in the digital workflow
EMAX
remember
processing steps for lithium disilicate
-CAD design
-Grinding with diamond bur
-Cooling
-Remove excess material e.g. sprue
-Sintering in vacuum furnace 30mins, 860c temp
-Finishing options
- Stain and glaze
- Polish
- Cutback and micro layering
- Cutback in design layered with enamel ceramic
what is feldspathic ceramic used for?
Veneering material over metal or ceramic substructures
what is Cutback or micro layered zirconia
feldspathic ceramic layered on top of zirconia to improve aesthetics
what are ceramic stains made of?
pigmented metal oxides
what colour is iron oxide
brown
what colour is cobalt
blue
what colour is copper
green
what colour is manganese
lavender
name an issue with all ceramic restorations
Translucency means can see metal underneath e.g. post
what is used to cement all ceramic restorations
resin modified GI or resin luting cement
All-ceramic restorations require surface treatment of either?
air abrasion or etching
