DENT MAT - Topic 4 (Part 2)

Glass Ionomer Cements

Formed by the reaction between glass powder and polyacrylic acid

Glass Ionomer Cements

It was developed in the 1970s to improve clinical performance compared with silicate cements and to reduce incidence of pulp damage

Type I

Luting crowns, bridges, and orthodontic brackets

Type II A

Esthetic restorative cements

Type II B

Reinforced restorative cements

Type III

Lining cements, base

Chemistry & Setting of GICs

There is a variation in powder composition, size, and viscosity depending on the desired function

Glass Composition of GICs

the basic composition is made up of silica, calcium, alumina, fluoride.

Liquid Composition of GICs

Original component: 40-50% polyacrylic acid but it was viscous and had shorter shelf life due to gelation.

Tartaric acid

rate-controlling additive which allows for a wider range of glasses to be used, improves handling properties, decreases viscosity, lengthens shelf life before gelation, increases working time, shortens setting time

Surface Preparation

Clean tooth surfaces with a pumice slurry (remove the smear layer

Material Preparation

The P/L ratio recommended by the manufacturer should be followed. A paper pad or a cool, dry glass slab may be used for mixing.

Material Placement & Fluoride Release

A tooth cavity should be slightly overfilled with GIC restorative.

Biological & Mechanical Properties

GICs elicit a greater pulpal reaction than ZOE cement but less than zinc phosphate cement.

METAL-REINFORCED GLASS IONOMER CEMENTS

Metallic fillers have been incorporated in GICs to improve their fracture toughness and stress-bearing capacity. They make the cement grayish and more radiopaque

Alloy admixture

metallic fillers are derived from
silver alloy powder

Cermet

metallic fillers are derived from particles of silver sintered to glass

HIGH-VISCOSITY GIC

They contain smaller glass particle sizes and use a higher P/L ratio, yielding greater compressive strength, and exhibit excellent packability for better handling characteristics.

RESIN-MODIFIED GLASS IONOMER CEMENTS

Water-soluble methacrylate-based monomers ARE used to replace part of liquid component of conventional GIC

Liquid Component of RMGIC

usually contains a water
solution of polyacrylic acid, HEMA, and polyacrylic acid modified with methacrylate

Powder Component of RMGIC

contains fluoroaluminosilicate
glass particles of a conventional GIC plus initiators, such as camphorquinone, for light curing
and/or chemical curing.

AS PIT AND FISSURE SEALANT

Low-viscosity hybrid ionomers or
conventional GICs

AS LINER AND BASE

Not indicated for pulp capping, place calcium hydroxide liner prior to hybrid ionomer

AS RESTORATION

Monomers in hybrid GICs make them more translucent

CALCIUM ALUMINATE GLASS IONOMER CEMENT

A hybrid product with a composition between that of calcium aluminate and GIC, designed for luting fixed prostheses.

COMPOMER

They are polyacid-modified composite made by incorporating glass particles of GIC in water-free polyacid liquid monomer with appropriate initiator (integration of the fluoride-releasing capability of glass ionomers with the durability of resin composites)

Water Uptake & Clinical Performance

is a desired process to complete the acid-base reaction and subsequent fluoride release.

Resin Cements

are low-viscosity versions of
restorative composites which are insoluble in oral fluids.

Organosilanes

ensure that the filler materials bond to the resins and create a durable, wear-resistant material.

ZINC OXIDE EUGENOL

Commonly used for luting and intermediate restorations because of its medicament quality and neutral pH

MINERAL TRIOXIDE AGGREGATE (MTA) CEMENT

It is made of a hydraulically active powder that combines calcium oxide (calcia, CaO), aluminum oxide (alumina, Al2O3), and silicon dioxide (silica, SiO2) into hydraulically active ceramic compound.

ENDODONTIC APPLICATIONS

As root-apex filling in endodontic surgery, apexification, root perforation repair, root resorption repair, obturation, and root canal sealing

VITAL PULP THERAPY

-Pulp capping
-Pulpotomy dressing

COMPATIBILITY WITH RESTORATIVE
MATERIALS

A hybrid ionomer liner or flowable
compomer may be placed and light-cured over MTA

ROOT CANAL SEALERS

are specialized versions of
cement used with gutta-percha to fill and seal debrided root canals.

ZOE-based (GOLD STANDARD)

The most popular root canal
sealers

CALCIUM PHOSPHATE CEMENTS

They are potentially useful water-setting cements because of their osteoconductive and osteoinductive properties.

Zinc Phosphate

has long served as the universal luting cement

Glass ionomer luting cements

bond to tooth structure, release fluoride, show greater resistance than zinc phosphate cements to disintegration, and have mechanical properties similar to those of zinc phosphate with the exception of a lower modulus of elasticity.