Resin Modified Glass Ionomer Cements Flashcards
1
Q
what is the chemical composition of the powder of RMGIC?
A
- fluro-alumino-silicate glass
- barium glass
- vacuum dried polyacrylic acid
- potassium persulphate
- ascorbic acid
- pigments
2
Q
what is the purpose of potassium persulphate in RMGIC?
A
redox catalyst to provide resin cure in the dark
3
Q
what is the chemical makeup of the liquid aspect of RMGIC?
A
- HEMA
- polyacrylic acid with pendant methacrylate groups
- tartaric acid
- water
- photo-initiators
4
Q
what is HEMA?
A
water miscible resin
5
Q
what is the purpose of tartaric acid found in RMGIC?
A
speeds up the setting reaction
6
Q
what photoinitiator tends to be found in RMGIC?
A
camphorquinone
7
Q
what is different about the setting reaction of RMGI compared to GI?
A
- on mixing the acid base reaction begins in the same way as GIC
- the redox reaction begins
- on light activation a free radical methacrylate reaction occurs resulting in a resin matrix being formed
- the redox reaction continues for about 5 mins after mixing
- acid base reaction continues within the resin matrix for several hours
8
Q
what are some good properties of RMGI/
A
- good bond to enamel and dentine
- better physical properties (compared to GI because of resin matrix)
- lower solubility
- fluoride release
- better translucency and aesthetics
- better handling
9
Q
some negative properties of RMGIC compared to GIC?
A
- polymerisation contraction
- exothermic setting reaction
- swelling due to uptake of water (HEMA is v hydrophilic)
- monomer leaching
- reduced strength if not light cured
10
Q
overall, what makes RMGIC superior to GIC?
A
- better aesthetics
- easier to use
- stronger
11
Q
what are advantages of using RMGIC over composite?
A
- easier to use
- fluoride release
