Glass Ionomer

Main types of GIC based on composition

Conventional glass ionomer (GI), resin modified glass ionomers (RMGI), Glass-hybrids, metal reinforced GI

Glass Ionomer cements classification

Type I:

Type II a:

Type II b:

Type III:

Type I: luting crowns, bridges, ortho brackets

Type II a: esthetic restorative cements

Type II b: reinforced restorative cements

Type III: lining cements, bases

Fuiji is what type

type IIa

What kind of reaction is it between the powder (fluoroaluminosilicate glass) and the liquid (aqueous solution of polyacrylic acid?

Acid base

Gi composition: essential components (4)

fluoroaluminosilicate glass (powder)

Polyacrylic acid (liquid)

Water

Tartaric acid

What is the water for in the GI acid base reaction

Helps ion transport in the acid-base reaction and fluoride release

What is tartaric acid for the GI composition reaction?

Helps to control the working time and setting characteristics of the material

GIC-Fuji Triage is used for (2)?

Sealant, transitional restorations

RMGI-Fuji II LC uses

permanent restorations (depending on location and size)

GIC - FUJI IX extra uses

temporary or permanent restorations (depends on location and size)

RMGI - Vitrebond plus uses

Liner

RMGI - FujiCem II uses

luting cement

3 main parts of the setting reaction

dissolution, gelation and initial setting, hydration of salts and maturation

What happens during gelation and initial setting

The carboxylate ions react w metallic ions to form salt bridge, resulting in gelation and setting, release of F-

Hydration of salts and maturation:

Strength of the cement builds with?

Silicic acid rapidly polymerizes to form?

with time, silica hydrogel

RMGI compositon components (4)

Polycarboxlic acid, fluroaluminosilicate glass, water (ion transport for acid-base rxn and fluoride release), hydrophilic methacrylate monomer (photo-initated redox rxn), free radical initators (trigger curing of methyl groups_

IN RMGI the..

Hydrophilic methacrylate monomer does what?

Free radical initaors do what?

Photo-initated redox reaction, trigger curing of methacrylate groups

RMGI two type of rxn?

Traditional acid base, free-radical methacrylate polymerization

Setting reaction RMGI:

water-soluble resin monomers into an aqeuos soltution of polyacrylic acid… next step

ion released from glass particle reacts with polyacrilic acid while hema occurs

compressive strength (mPA) place in order of least to most

RMGI, RBC, enamel, dentin, GI

1. GI

2. RMGI

3. dentin

4. RBC

5. enamel

Flexural Strength (MPa)

place in order: RMGI, RBC, enamel, dentin, GI

1. GI

2. RMGI

3. RBC

Tensile strength

RMGI, RBC, enamel, dentin, GI

1. GI/enamel

2. RMGI

3. RBC

4. Dentin

Fracture toughness (MPA m1/2)

RMGI, RBC, enamel, dentin, GI

1. GI

2. RMGI

3. RBC

4. enamel

5. dentin

Wear rate

RMGI, RBC, enamel, dentin, GI

1. RBC

2. enamel

3. GI

from left to right? Compomer, GI, RMGI, Resin composite

GI, RMGI, Compomer, Resin composite

Fluoride release and recharge. Highest level is from ?

Recharged with?

Best balance of F- release, recharge, physical properties is?

GI and RMGI

f toothpaste, rinses, varnishes

Resin modified glass ionomer (RMGI)

Conditioning: what the rule?

rule of 200: % * time = 200

Two mechanisms of adhesion

micromechanical interlocking interdiffusion layer

chemical bonding: ionic bonds between carboxyl groups and calcium from hydroapatite

Do not desiccate dentin before?

application (needs to be moist in clinic)

craze lines are due to?

loss of water

What is recommended to protect GI from loss and uptake of water during setting

transient surface protectant (vaseline)

what are two cititical roles water plays in setting of GIC

1. Rxn medium in intial dissolution

2. Hydration over time as it matures