Glass Ionomer Cements: Chemistry and Clinical Applications

Glass Ionomer Cement (GIC)

• Setting reaction involves an acid-base reaction between the glass powder and the liquid component.
• The acid-base reaction involves the decomposition of glass powder.
• Conventional GIC's liquid component is composed of a polyacrylic acid and water.
• The main purpose of the maturation phase in GIC setting is to achieve the maximum strength of the cement.

Clinical Applications of GIC

• Applying GIC in different clinical cases involves selecting the appropriate type and composition of GIC for the specific needs of the patient.
• The learning outcome related to applying GIC involves understanding the clinical indications and contraindications of GIC.

Composition and Properties of GIC

• An increase in the Al/Si ratio in glass composition increases the setting rate of GICs.
• Thermal diffusivity of GICs is influenced by the composition of the glass powder.
• Adding fluoride to GICs does not affect their esthetic properties.
• Fluoride release from GICs occurs through a process of ion exchange and diffusion.

Resin-Modified Glass Ionomer Cements (RMGICs)

• The main reason for shrinkage in RMGICs is the polymerization of the resin component.
• RMGICs adhere to tooth structure through a combination of mechanical and chemical bonding.

Conventional Glass Ionomer Cements (GICs)

• Conventional GICs adhere to tooth structure through a combination of mechanical and chemical bonding.
• Adding light-cured bonding agents to GICs improves their bonding to tooth structure.
• An increase in powder/liquid ratio affects the setting rate of GICs.

Setting Reaction of GIC

• During the gelation phase of GIC setting, the cement starts to set and becomes less fluid.
• Including tartric acid in the liquid component accelerates the setting rate of GICs.
• Fluoride release from RMGICs occurs more rapidly than from conventional GICs.

Uses of Cements in Dentistry

• The main use of cements in dentistry is for restorative and preventive procedures.
• The rationale for using cavity lining materials in dentistry is to protect the tooth from thermal and mechanical stresses.

Properties and Uses of Cements

• Cements based on Organometallic Chelate Compounds are used for temporary restorations.
• Cements based on Phosphoric Acids are used for permanent restorations.
• A requirement of cavity lining materials is to provide a thermal barrier between the tooth and the restorative material.
• The main purpose of placing a thin layer of cavity lining material inside a prepared cavity is to prevent thermal and mechanical stresses.

Cavity Lining Materials

• The purpose of lining the walls and base of shallow cavities with varnish is to prevent microleakage.
• It is important for cavity linings to be radiopaque to facilitate detection on radiographs.
• The integrity of a lining depends on the bonding between the lining and the tooth.

Zinc Oxide Eugenol Cements

• Zinc oxide eugenol cements are characterized by their antibacterial properties and low acidity.
• The primary reactive agent in the liquid component of zinc oxide eugenol cements is eugenol.
• The primary function of zinc phosphate cements is to provide a permanent restoration.