GIC properties and types

Question 1

What are the positives of GIC?

Answer 1

• Adhesion: no need for micro-mechanical retention
• Fluoride release
• Complete isolation not required
• Ion exchange layer
• Relatively biocompatible
• Similar coefficient of thermal expansion as the normal tooth

Question 2

What are the negatives of GIC?

Answer 2

• Aesthetics inferior to composite resin
• Prolonged setting for autocure systems
• Setting contraction of 2-3% for light sure systems
• Not as strong as composite and amalgam
• Very susceptible to dissolution and disintegration: Over- drying = cracks, over wetting = softening
• Fracture resistance: very brittle and susceptible to fracture
• Wear: limited wear resistance, therefore it should not be used on occlusal bearing surfaces
• Water sorption: resin- modified GIC uptakes water

Question 3

List the composition of conventional GIC

Answer 3

• Glass: 95% Fluoroaluminosilicate glass
• Powder: 5% ployacrylic acid powder

Liquid:

• 50% distilled water
• 40% polyalkenoic acid
• Tartaric acid: controls setting time, extends working time and fastens setting time

Question 4

List the composition of resin- modified GIC

Answer 4

Glass: fluoroaluminosilicate glass

Liquid:
20 - 30% distilled water 
20 - 30% polyalkenoic acid
30 - 35% Hydroxy- ethyl- methacrylate (HEMA)
<10% Urethane Dimethacrylate (UDMA)
<1 Camphoroquinone

Question 5

What is the fluoroaluminosilicate glass composed of?

SACCA

Answer 5

• Silica
  30%
• Aluminum oxide
  16%
• Calcium Fluoride
  34%
• Cryolite
  5%
• Aluminium phosphate 10%