Used as both a restorative material and also a luting cement. It has poor strength compared to other restorative materials (e.g. amalgam, composite)
Composition
Powder (Base) – ALUMINIUM SILICATE GLASS
+
Liquid (Acid) – POLYACRYLIC ACID + water or TARTARIC ACID + water or POLYMALEIC ACID + water
Advantages
Bonds to the tooth surface chemically (ionic cross-linking)- resulting in high strength adhesion
Favourable thermal expansion especially with dentine
Aesthetics can be acceptable compared to other restorations, but inferior to composite
May release fluoride
Bonds better to dentin than enamel
Disadvantages
Technique sensitive – poor mixing/mixing ration may result in decreased toughness/resistance/strength
Bonds better to dentine than enamel
Indications
Small Class I,III cavities
Class V cavities
Patients with high caries risk
As a baseliner in GI/Comp Sandwich fillings
Cementation of metal restorations, orthodontic brackets
Areas of poor moisture control
Children/disabled patients
Contra-indications
Large restorations
Class II, IV cavities
Technique
Clean dry isolate cavity
A conditioner of polyacrylic acid is placed for 20s – this removes the smear layer of dentine and releases ions.
Wash off and leave dentine slightly wet.
The glassionomer is placed in one bulk; no layering
A varnish is placed over the restoration
The restoration cures by itself – this may take hours/days and so finishing/polishing is contraindicated.
dentalsmackers 