Glass Polyalkenoates

Question 1

4 properties of Ion Leachable glass

Answer 1

Adhesive
Better appearance
Less solubility
Better mechanical properties

Question 2

What acid is in polycarboxylate cements?

Answer 2

Polycarboxylic acid

Question 3

When did the peak of GI development happen?

Answer 3

1970’s

Question 4

What forms can GI come in?

Answer 4

Powder : Liquid
Powder : Water
Encapsulated

Question 5

What powder is used in the P:L state?

Answer 5

Sodium aluminosilicate Glass with 20% CaF

Question 6

What powder is used in the P:W state?

Answer 6

Sodium aluminosilicate Glass with 20% CaF PLUS vacuum dried POLYACID

Question 7

What liquid is used in the P:L state?

Answer 7

Aqueous solution of acrylic acid copolymer PLUS Tartaric acid

Question 8

What does Tartaric acid do?

Answer 8

Controls the settting

Question 9

What mixing technique should be used with a scoop and drop bottle?

Answer 9

Oscillatory

Question 10

What is the porosity in viscous cements compared to fluid cements?

Answer 10

There is lower porosity with viscous cements

Fluid cement is split into hand mixed and mechanically mixed: Mechanically mixed results in more porosity.

Question 11

Which has the highest setting time out of Restorative/Luting/Lining

Answer 11

Luting is 2.5-8 compared to 2-6.

Question 12

Which has the highest compressive strength out of Restorative/Luting/Lining?

Answer 12

Restorative with 130 compared to 70

Question 13

Why should you not leave the liquid in the fridge?

Answer 13

It is difficult to mix by hand as it initiates the acid crystallisation

Question 14

How is GI bonded to the tooth?

Answer 14

By Calcium ions

To collagen by H bonding and metallic ion bridging

Question 15

What acid increases the bond strength?

Answer 15

Polyacrylic

Question 16

Describe Enhanced bond strength

Answer 16

You can only bond to the limit of the tensile strength of GI cement- if it is any greater then COHESIVE CEMENT FAILURE will occur.

Question 17

Give 7 properties of GI

Answer 17

Thermal diffusivity close to dentine
Brittle (15-20 MPa)
Chemical set is exothermic (2-5º)
Fluoride release and uptake
Poor abrasion resistance
Lack in radiopacity
It is susceptible to acid erosion

Question 18

What is a cermet?

Answer 18

Heat resistant material

Question 19

What properties does a cermet have?

Answer 19

Increase compressive strength

poor appearance

Question 20

What is the filler replaced by in Modified composite?

Answer 20

Aluminosillicate Glass which encourages fluoride release

Question 21

How is Modified composite set?

Answer 21

Set by Light cured free radicals polymerisation

Question 22

When does the acid base reaction occur in Modified composite?

Answer 22

Late on as- Water enters when the resin is set and the acidic groups in the resin are ionised. This is the acid base reaction.

Question 23

What is the composition of a Giomer?

Answer 23

The same as Modified composite BUT- Aluminosilicate is pre-reacted with polyacid to form a GLASS POLYALKENOATE COMPLEX

Question 24

What are the 2 types of Giomer reaction?

Answer 24

Surface and Full

Question 25

What is the surface reaction in a Giomer

Answer 25

Reaction with only particles at the surface

Better physical properties

Question 26

What is the full reaction in a Giomer?

Answer 26

Reaction with all the particles

It allows mixing of HEMA

Question 27

How are Giomers set?

Answer 27

Both types are single paste VLC free radical polymerisation set.

Question 28

What forms does RMGIC come in?

Answer 28

Encapsulated or P:L

Question 29

What is the powder in RMGIC?

Answer 29

Ion Leachable glass

Question 30

What is in the liquid in RMGIC? (5)

Answer 30

Methacrylate resin (allowing the setting by polymerisation)
Water (for ionisation and acid/base reactions)
Polymerisation activators
Poly acid
HEMA (enables resin to exist as aqueous solution)

Question 31

What is an example of a chord structure?

Answer 31

Gi

Alloys