GI + RMGI

Question 1

good properties of GI

Answer 1

similar dentine thermal expansion
fluoride releasing
aesthetics
bonds to enamel + dentine
no contraction on setting
good seal
doesn’t need etched

Question 2

bad properties of GI

Answer 2

reduced bond strength, tensile, compressive, wear resistance
increased solubility = water sorption

Question 3

mechanism of GI bonding to tooth structure

Answer 3

carboxyl groups + Ca in enamel
hydrogen bonding, metallic ionic bridge

Question 4

components of GI

Answer 4

acid =
polyacrlyic acid

powder (base) =
silica, alumina
CaF, AlF, AlPh
lithium salts

Question 5

name and describe the setting reaction of GI

Answer 5

DISSOLUTION
H+ ions attack glass surface
Al, Ca, Na, F ions released
leaves silica around unreacted glass

GELATION
initial set due to Ca+ ions cross linking with poly acrylic acid by chelation w carboxyl group
hardens by formation of calcium polyacrylate

HARDENING
trivalent Al increases crosslinking
30mins - 1 week
increases mechanical properties

Question 6

properties of RMGI (as compared to GI)

Answer 6

improved physical prop
decreased solubility
fluoride release lower
increased translucency and aesthetics
better handling

Question 7

components of RMGI

Answer 7

powder =
fluoroaluminosilicate glass
barium glass
poly acrylic acid
pigments

liquid =
HEMA
polyacrylic acid
tartaric acid
water
photo initiator LIGHT CURE

Question 8

what component of RMGI allows light cure and is it in powder or liquid

Answer 8

photo initiator
liquid

Question 9

dual cure setting reaction of RMGI

Answer 9

mixing causes dissolution
light activation - free radical methacrylate reaction = forms resin matrix
acid/base reaction 2hrs

Question 10

tri curing setting reaction of RMGI

Answer 10

mixing causes dissolution
redox reaction
light activation - free radical methaclryate - forms resin matrix
final hardening takes days