Flashcards in Glass polyalkenoates Deck (20):
what are glass polyalkenoates derived from?
re. polycarboxylate cements what reacts with what?
zinc oxide reacts with polycarboxylic acid
what replaced zinc oxide?
ion leachable glass
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
what else is involved re. setting reaction of glass polyalkenoate?
why reacts with calcium first?
calcium on outer layer
calcium ions more mobile in solution to move toward acid
what are the three mechanisms of setting re glass polyalkenoate?
transport analogy re. 2 + / 3+
what is powder component of glass polyalkenoate?
sodium aluminosilicate glass with calcium fluoride
what % calcium fluoride in glass polyalkenoate?
what does porosity cause?
stress, crack, inferior properties
what does a higher viscous cement mean re. porosity?
higher viscosity, lower porosity
mixing by hand means what with porosity?
how does glass polyalkenoate bond to tooth?
with calcium ions
also to collagen by hydrogen bonding and metallic ion bridging
what may boost bonding?
tooth cleanser- citric acid- removes smear layer
what increases bonding strength?
what is a cermet?
silver pellatized mixture of glass and metal particles
in modified composites what replaces filler?
what is a giomer?
composition as for composite but aluminosilicate glass is pre reacted with poly acid
two types of giomers?