Glass-Ionomer Cements: Applications in Dentistry

From their invention in 1971 to resin-modified formulations, why fluoride release remains the distinctive advantage of glass-ionomer cements over any other restorative material.

Glass-ionomer cements were developed in 1971 by Wilson and Kent, appearing on the European market in 1975 and on the American market two years later. Early formulations had significant limitations in terms of hardness, wear resistance and tensile strength, but subsequent research progressively improved these physical properties, substantially widening the range of clinical applications for this material.

The distinctive advantage of glass-ionomer cements compared to composites and other restorative materials remains prolonged release of fluoride ions, able to buffer acids produced by bacterial metabolism and inhibit the growth of cariogenic species like Streptococcus mutans — a direct cariostatic benefit no other restorative material offers to the same extent. Added to this are excellent biocompatibility, genuine chemical (not just mechanical) adhesion to tooth structure, and a thermal expansion coefficient close to that of natural dentin, which reduces stress at the restoration-tooth interface during oral cavity temperature changes.

The main limitations of conventional glass-ionomer cement are mechanical strength not comparable to that of composites, which makes it unsuitable for areas subject to high chewing loads, and high sensitivity to moisture during setting, requiring near-absolute isolation of the operative field. To partly overcome these limitations, several variants have been developed: resin-modified glass-ionomer cements, which reduce moisture sensitivity and improve initial strength thanks to an added light-curable component; and compomers, polyacid-modified composite resins that release fluoride at an intermediate level — less than pure glass-ionomers but more than conventional composite resins.

The most well-established clinical indications include fillings in primary teeth (where expected restoration lifespan is limited by tooth exfoliation anyway), Class V restorations in high-caries-risk patients, cement for fixed and orthodontic prosthetics, and provisional or intermediate fillings within the ART (Atraumatic Restorative Treatment) technique, where ease of handling and no need for rotary instrumentation make glass-ionomer particularly suited to non-optimal operating conditions.

On Oralzon you'll find conventional, resin-modified glass-ionomer cements and compomers for every clinical indication, from direct restoration to prosthetic and orthodontic cementation.