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Flashcards in Glass polyalkenoates Deck (20):
1

what are glass polyalkenoates derived from?

silicate cements
polycarboxylate cements

2

re. polycarboxylate cements what reacts with what?

zinc oxide reacts with polycarboxylic acid

3

what replaced zinc oxide?

ion leachable glass

4

describe setting reaction re. glass polyalkenoate

glass contacts acid
glass has chord structure
outer surface rich in calcium
initial setting on calcium ions as predominant on outer surface of glass

5

what else is involved re. setting reaction of glass polyalkenoate?

aluminium

6

why reacts with calcium first?

calcium on outer layer
calcium ions more mobile in solution to move toward acid

7

what are the three mechanisms of setting re glass polyalkenoate?

concentration gradiet
mobility
transport analogy re. 2 + / 3+

8

what is powder component of glass polyalkenoate?

sodium aluminosilicate glass with calcium fluoride

9

what % calcium fluoride in glass polyalkenoate?

20

10

what does porosity cause?

stress, crack, inferior properties

11

what does a higher viscous cement mean re. porosity?

higher viscosity, lower porosity

12

mixing by hand means what with porosity?

less porosity

13

how does glass polyalkenoate bond to tooth?

with calcium ions
also to collagen by hydrogen bonding and metallic ion bridging

14

what may boost bonding?

tooth cleanser- citric acid- removes smear layer

15

what increases bonding strength?

polyacrylic acid

16

what is a cermet?

silver pellatized mixture of glass and metal particles

17

in modified composites what replaces filler?

aluminosilicate glass

18

what is a giomer?

composition as for composite but aluminosilicate glass is pre reacted with poly acid

19

two types of giomers?

surface reaction
full reaction

20

what is liquid re. glass polyalkenoate?

aqueous solution of acrylic / itaconic acid copolymer plus tartaric acid to control setting