Direct Dental Restorative Materials: GIC and RMGIC

Practice vocabulary flashcards covering the composition, setting reactions, bonding mechanisms, and clinical applications of Glass Ionomer Cements and their resin-modified counterparts.

GIC (Glass Ionomer Cement)

A tooth-coloured restorative material that sets via a pure acid-base reaction between fluoro-alumino-silicate glass and polyacrylic acid.

RMGIC (Resin-Modified Glass Ionomer Cement)

A hybrid material containing a combination of acid-base GIC components and light-cured resin, allowing for a command set.

Compomer

A resin-based restorative material containing acid-reactive filler.

Modified GIC Formula

A presentation where polyacrylic and tartaric acids are freeze-dried and mixed into the powder, requiring only distilled water for activation.

Hydrolysis (Activation)

The first stage of the GIC setting reaction where water ionises the carboxyl groups into $COO^-$ and $H^+$.

Acid Attack

The second stage of GIC setting where $H^+$ ions attack the glass surface, releasing $Ca^{2+}$, $Al^{3+}$, $F^-$, and $Na^+$ ions.

Gelation

The third stage of GIC setting where $Ca^{2+}$ ions rapidly crosslink adjacent $COO^-$ chains to create the initial set.

Maturation

The final stage of GIC setting, occurring over approximately $24$ hours, where $Al^{3+}$ ions form stronger, slower-diffusing crosslinks.

Tartaric Acid

An additive in GIC liquid that improves working time, reduces setting time, and increases compressive strength.

Maleic Acid

An additive that improves the solubility of polyacrylic acid in water and aids in fluoride and calcium release.

Itaconic Acid

An additive that improves polyacrylic acid solubility and helps create a denser crosslinked network.

Ionic Bond

The primary chemical bond formed between the $COO^-$ groups of GIC and the calcium in tooth hydroxyapatite.

Hydrogen Bond

A secondary bonding mechanism between GIC and the collagen in the organic matrix of dentine.

Surface Conditioning

The application of $10-20\%$ polyacrylic acid for $20$ seconds to remove the smear layer before GIC placement.

$$7\,MPa$$

The approximate tensile bond strength of GIC to dentine.

$$20\,MPa$$

The approximate bond strength of resin bonding agents.

Desiccation

The process of over-drying GIC, which retards the setting reaction because the reaction requires water.

P/L Ratio (Powder/Liquid Ratio)

A factor where an increase leads to decreased setting time and increased compressive strength.

GC Fuji IX

A specific product used as a standard conventional GIC restorative.

GC Fuji VII

A high fluoride-releasing GIC used for cavity linings, base materials, and fissure sealants.

ART (Atraumatic Restorative Treatment)

A clinical treatment modality where GIC is frequently indicated.

HEMA (Hydroxyethyl methacrylate)

The resin monomer added to RMGIC that undergoes addition polymerisation.

Addition Polymerisation

The free-radical mechanism in RMGIC where monomers join to form long-chain polymers through initiation and propagation.

Command Set

The ability of RMGIC to be light-cured on demand, allowing for immediate finishing and contouring.

GC Fuji II LC

An RMGIC product noted for having excellent aesthetics.

GC FUJI PLUS

An RMGIC cement used specifically for crown and post-core cementation.