FP - all ceramic restorations Flashcards
what are advantages of ceramic restorations (3)?
close approximation to natural tooth tissue
highly biocompatible
certain systems can be provided same day
list disadvantages of all ceramic restorations (4)?
prone to fracture
require larger reductions in tooth tissue
cost
reduced scope for adjustment/ repair
how are dental ceramics classified?
composition or method of manufacture
list the 4 compositions of ceramic
- glass based
- glass infiltrated
- polycrystalline
- resin matrix ceramics
what are the 3 types of glass based ceramics?
feldspathic glass
moderately filled glass ceramics
highly filled glass ceramics
what type of glass based ceramic is the most brittle and prone to fracture?
feldspathic
what type of glass based ceramic is the least aesthetic?
highly filled glass ceramic
what are the types of glass infiltrated ceramics?
alumina
magnesium or zirconia infiltrated with low viscosity glass (In-Ceram)
what are polycrystalline (non-glass) ceramics based off?
alumina or zirconia
what type of ceramic is similar to composite?
resin matrix ceramics
what are the 3 types of method of manufacture for ceramics?
sintering
hot pressing/ injection moulding
machining
describe sintering
ceramic powder mixed with water is built to the required shape and exposure to high temp causes partial melting and fusing of particles
describe hot pressing/ injection moulding
similar to lost wax technique
wax up of restoration is invested in refractory die and a heated block of ceramic is injected under pressure
describe machining
CAD/CAM impression
milled from block of ceramic
describe the difference between monolithic and bilayer ceramic crowns
monolithic - machined from single block of ceramic
bilayer - coping made from highly filled glass ceramic or zirconia, more aesthetic feldspathic porcelain is then built onto the coping
