resin modified GIC and compomers

Question 1

What material come under glass ionomers

Answer 1

resin modified GIC
glass carbomer
Glass polyvinyl phosphonates
cermets and miracle mix

Question 2

what comes under resin composites

Answer 2

glomers
polyacid modified composites or compomers
ormocers

Question 3

Resin modified GIC

Answer 3

like GIC but addition of water miscible monomer hydroxyethylmethacrylate (HEMA) and photo inisiator

Question 4

how does resin midified GIC set

Answer 4

acid base reaction and photopolymerisation

Question 5

bonding system resin modified GIC

Answer 5

shares GIC chemical bond to untreated dentine/enamel, no need to bonding system

Question 6

vitremer

Answer 6

glass ionomer cement plus HEMA

- with photo initiators and encapsulated iniator setting reaction

Question 7

setting reaction of viremer

Answer 7

dissolution 
gelation 
hardening 
light cure
polymerisation

Question 8

what does the addition of OH group in resin do

Answer 8

increases the immiscibility in water making RMGIC less hydrophobic than coventiional resin composites

Question 9

composition of polyacid modified resin compootie

Answer 9

fluoride releasing glass (instead or the normal filler)

Polymerisiing resin

Question 10

what is the polymerising resin for polyacid modified resin composite composed of

Answer 10

ethylele urethan dimethacrylate(UDMA)
photo initiator
resin monomer modified with carboxylate side chains

Question 11

how does polyacid modified resin composite release fluoride

Answer 11

restoration will abrorb water from the environment and then the proton is free to move through material
- attacks basic releasing glass
- get fluoride release from the polymerising resin
(they need to absorb water before they release fluoride)

Question 12

what is the fluoride releasing glass in polyacid modified resin composites

Answer 12

strontium fluoride

Question 13

trends in the dental market

Answer 13

amalgam use declines, aesthetec direct restorative materials will increase in use
caries rates may fall with fluoride toothpaste
tooth loss will occur later in life

Question 14

compsoite and water

Answer 14

hydrophobic so needs bonding system

Question 15

adv of composite

Answer 15

aesthetic
durable
safe

Question 16

dis of composite

Answer 16

composite shrinkage
tehcninique sensitve
requires a bonding

Question 17

glass ionomer cements

Answer 17

relatively durable
insoluble
fluoride releasing
aesthetic -ish

Question 18

dis of GIC

Answer 18

not as aesthetic
susceptible to wear
- due to large particle size

Question 19

GIC compositon

Answer 19

fluoroaluminosilicate glass
polymeric acid
water
tartaric acid

Question 20

how is GIC formd

Answer 20

acid base reaction where metal cations form salt bridges with ionised carboyylate acids group on high molecular weight polyacids

Question 21

what is the powder part of GIC

Answer 21

fluro alumínio silicte glass
freeze dried polyacrylic acid
pigments

Question 22

liquid part of GIC

Answer 22

polyacrylic
tartaric acid
distllled water

Question 23

phases of acid base reaction of GIC

Answer 23

1) Dissolution
- acidic attack of glass surface
2) Gelation
- early cross linking by Ca2+
3) Hardening
- substitution of Ca2_ by Al3+

Question 24

acid base reaction sequence GIC

Answer 24

• carboxylic acid residues of polymer chains will release their proton and therefore will ionise in the presence of water
• basic glass is available to react with the proteins
• acidic attack of glass particle surface liberating some of the surface cations
• Metal ions are released from the surface of the glass
• start to form salt bridges, adjacent carboxylic acid residues stabilised by the charge on the cations
  the end result is a composite biomaterial of acid degraded glass particles set in a cross linked hydrogen matrix

Question 25

properties attributed to glass ionomer cements (ad and dis)

Answer 25

• Adhesion to mineralised tooth tissues (GIC is water based)
• F- release and associated protection against caries
• antibacterial activity?
• set without exotherm and no shrinkage
• biocompatible
• may be radiopaque

Bu relatively poor aesthetics (less translucent than normal tooth tissue) poor wear resistance, brittle, no command set (once components mixed they start to set), technique sensitive

Question 26

clinical uses of GIC

Answer 26

1) restoration of deciduous primary teeth
2) class V restorations in permanent teeth
3) erosion/abrasion
4) fissure sealants
5) atraumatic restorative treatment
6) luting cements
7) cavity bases
Contra indicated for highly loaded sites eg cuspal or incisal edge, or where aesthetics are important (can see GIC)