Plastic restorations - Resin modified glass ionomer cements

Question 1

What is a resin modified glass ionomer?

Answer 1

it is close to a glass ionomer but has some resin it

Question 2

What are the 2 hybrid materials?

Answer 2

compomer and resin modified glass ionomer

Question 3

What are the advantages of resin based composites?

Answer 3

command set by visible light

better wear resistance

lower solubility

early compressive and flexural strength

good polishability

ability to retain its polish

Question 4

What are the disadvantages of glass ionomer cements?

Answer 4

lower early strength

susceptibility to erosion

slower setting phase

risk detection

Question 5

is resin hydrophobic or hydrophilic?

Answer 5

hydrophobic effectively

Question 6

What are the constituents of RMGICS? (BASIC)

Answer 6

Are conventional glass ionomer cements and water-soluble resin and modified poly(acrylic acids)

Question 7

What are olyacrylic acids?

Answer 7

they have pendant methacrylate groups or methacryloxy groups grafted onto the polyacid chain (copolymers)

= copolymers

Question 8

What is the resin group?

Answer 8

usually HEMA

Question 9

What is the glass ionomer part?

Answer 9

polyacid

tartaric acid

water

ion leachable glass

Question 10

What is the resin part?

Answer 10

water soluble (miscible) monomer

Question 11

What us HEMA?

Answer 11

SMALL HIGHLY REACTOVE MONOMER MOLECULE

Question 12

Is glass ionomer hydrophobic or hydrophilic?

Answer 12

hydrophilic

Question 13

What connects the hydrophobic resin composite and hydrophilic GI?

Answer 13

HEMA

Question 14

What is the problem with HEMA?

Answer 14

it is a powerful dermatological sensitizer causing chemical dermatitis

Question 15

What form is HEMA a hazard?

Answer 15

in the unset form, after polymerisation it is fine

Question 16

What will happen f the level of HEMA polymerisation is low?

Answer 16

then unconverted monomer can leach out as polyHEMA which absorbs water very quickly

Question 17

What is the effect of freed HEMA monomer?

Answer 17

move into surrounding dental hard and surrounding tissues

may potentially have toxological effects on the dental pulp and osteoblasts if polymer degrades

Question 18

How does RMGIC decrease microleakage?

Answer 18

it seals the dentinal tubules opened during cavity preparation and decreases the risk of microleakage

decrease microcontamination

Question 19

What are the constituents of RMGIC? (powder)

Answer 19

Barium, strontium or aluminosilicate glass

vacuum-dried polyacrylic acid

potassium persulphate

ascorbic acid

pigments

Question 20

Why use barium, strontium or aluminosilicate glass? (powder)

Answer 20

improved strength

imparts radiopacity

Question 21

What reaction makes the poly salt matrix? (powder)

Answer 21

vacuum-dried polyacrylic acid and glass

Question 22

What provides the chemical cure (powder)

Answer 22

potassium persulphate

ascorbic acid

Question 23

What are the chemical constituents? (liquid)

Answer 23

Question 24

What does polyacrylic acid react with (liquid)?

Answer 24

reacts with the glass to form the poly salt matrix

Question 25

What does the copolymer do (liquid)?

Answer 25

ability to undergo both acid-base and polymerisation reactions helps form interpenetrating network (the set)

Question 26

What is the polymerisation reaction due to?

Answer 26

resin

Question 27

What is the acid-base reaction due to?

Answer 27

Glass ionomer

Question 28

What sharpens the acid-base reaction set? (liquid)

Answer 28

tartaric acid

Question 29

What is the role of water in RMGIC? (LIQUID)

Answer 29

permits reaction between the polyacid and the glass

Question 30

What happens to translucency as particle size is reduced?

Answer 30

as particle size is reduced there is a progressive loss in translucency (gets more opaque)

Question 31

What reaction does the water-miscible monomer permit?

Answer 31

polymerisation reaction

Question 32

What else happens during the polymerised resin phase?

Answer 32

it forms a scaffolding while the ionomer cement matrix is being formed

Question 33

What happens as the resin content is increased?

Answer 33

the acid-base reaction is slowed as the resin matrix decreases the motility of the other ions to form the chemical reaction

Question 34

When is the effect of the resin addition primarily seen?

Answer 34

during the initial stages of the set when the glass ionomer cement is weakest

Question 35

Why does the resin need to be soluble in water?

Answer 35

as the cement remains water based

Question 36

What happens if there is an absence of water?

Answer 36

there is no reaction between the polyacid and the glass

Question 37

Why is there a limit in the number of resin systems used in the material?

Answer 37

due to its hydrophobicity

Question 38

What 2 types of setting reaction stake place in the material?

Answer 38

acid-base polymerisation