Glass Ionomer Cement

Restorative - filling material, endodontic access cavity temporary filling Core build up - prior to crown placement Lining - underneath restorations Luting - cementing indirect restorations Fissure sealant Orthodontic cement

Acid - liquid Base - glass powder

Dissolution - bath bomb Gelation - calcium ion cross linking Hardening - aluminium polyacrylate formation

Acid into solution H+ ions attack the glass surface Ca, Al, Na & F ions are released Leaves silica gel around unreacted glass

Calcium ion crosslinking with the polyacid by chelation with the carboxyl groups. Caused by formation of calcium polyacrylate. Equates to the initial set of the material. Takes several minutes depending on the particular material. Following this, the material appears hard in the mouth.

Does not start for at least 30 mins and can take a week+ to complete. Trivalent aluminium ions ensure a higher degree of crosslinking and increase strength. Triggered by aluminium polyacrylate formation? Improves mechanical properties of material.

Aluminium ions diffuse out Excessive drying - water will be lost Saliva contamination - absorption of water Weak material Poor aesthetics

Varnishes (copal ether, acetate) Resins (DE bonding agents) Greases or gels (vaseline)

To improve ease of use as older formulations had v long working and setting times.

5MPa Bonds without need for an intermediate material

Chelation between carboxyl groups in the cement and Ca on the tooth surface. Hydrogen bonding or metallic ion bridging to collagen.

Clean surface Conditioned surface (e.g. polyacrylic acid)

Colour okay but lacking in translucency New materials with higher silica content are better Translucency improves over 24hrs due to extra cross linking

Expansion similar to dentine No contraction on setting

Poor tensile strength Lower compressive strength than composite Poor wear resistance Lower hardness than composite Higher solubility than composite

Doesn’t damage the GIC structure Beneficial against secondary caries Inhibits bacterial growth Ability to recharge it’s fluoride supply

Stable chemical bond to enamel and dentine Low microleakage Fluoride release Good thermal properties - no contraction on setting

Brittle Poor wear resistance Moisture susceptible when first placed Poor aesthetics Poor handling characteristics Susceptible to acid attack & drying out over time Possible problems bonding to composite

Material composed of ceramic and metallic materials. Silver was added to the glass to increase toughness and wear resistance of GIC. Only ended up making silver GIC.

GIC with added 75% HEMA bis-GMA Combine the acid-base reaction of traditional GIC with a self-cure amine-peroxide polymerization reaction. Developed to overcome the disadvantages of traditional GIC - command set, improved physical properties, better aesthetics.

Powder: Fluoro-alumino-silicate glass Barium glass Vacuum dried poyacrylic acid Potassium persulphate Ascorbic acid Pigments Liquid: HEMA Polyacrylic acid with pendant methacrylate groups Tartaric acid Water Photo-initiators

Provides radiopacity

Redox catalyst to provide resin cure in the dark

Varies shade