Glass Polyalkenoate Restorative Materials Flashcards
Name the 3 forms in which Glass polyalkenoate could be supplied
- Powder and liquid
- Powder and water
- Encapsulated
Composition of powder and liquid in glass polyalkenoate
powder: Sodium aluminosilicate glass with about 20% CaF2
liquid: aqueous solution of acrylic/itaconic acid polymer + tartaric acid
Type of reaction undergone by mixing of glass (powder) and aqueous poly(alkenoic) acid
Acid-base reaction
Which ions are released in the decomposition of glass particles?
Calcium
Aluminium
What does the set material consist?
unreacted glass cores embedded in a matrix of cross linked polyacid (siliceous hydrogel + water)
Describe the structure of set material
Heterogenous, with a core of unreacted glass particles
Which ion is released more rapidly in the early stages?
Calcium
Properties of glass polyalkenoates x8
- thermal diffusivity
- chemical set (exothermic)
- fluoride release and uptake
- brittle
- poor abrasion resistance
- susceptible to acid erosion
- lack of radio-opacity
- good appearance
What are Cermets?
Composite materials in which ceramic materials and metals are joined together
Silver pelletized mixture of glass and metal particles
Properties of Cermets x6
- radio-opacity
- poor appearance
- some fluoride release
- increased compressive strength
- increased fatigue limit
- same flexural strength and abrasion resistance
How is the modified composite different?
Filler is replaced with aluminosilicate glass to encourage fluoride release
Setting reaction of modified composite?
initially: light cured
late: acid base
