GLASS-IONOMER CEMENTS - PAST, PRESENT AND FUTURE

It was Michael Buonocore who focused the attention of the profession o n adhesion in the oral cavity. He expanded the concept of adhesion of resins to enamel and investigated adhesion to dentin. The problem has been solved through the glass-ionomer cements rather than with resins, but sadly, he did not live to see them achieve maturity. The glass-io nomer cements were introduced to the profession in 1976, and they prov ide adhesion to both enamel and dentin through an ion exchange with th e additional benefit of a continuing fluoride release throughout the l ife of the restoration. Solubility is low, abrasion resistance is high , and biocompatability is excellent. As a water-based material, they h ave an excellent chance of survival in the hostile environment of the oral cavity. Acceptance of the early versions was slow because of perc eived problems with water exchange, a poor color range, and a lack of translucency. Considerable research has been carried out over the last 20 years by members of the profession and the manufacturers; at this point, the glass-ionomer cements make a very valuable contribution to everyday practice. They are now available as both an autocure and a du al-cure cement, and the color range and translucency are excellent. Pr oblems of clinical placement have been overcome, and it is now a simpl e matter to take advantage of the adhesion and the fluoride release an d place a restoration that is esthetic, resistant to microleakage, lon g lasting, and a deterent to recurrent caries. Their only limitation l ies in the fact that they lack the fracture strength to rebuild margin al ridges and incisal corners. In spite of this limitation, they have opened the way for the introduction of a new range of microcavity desi gns that allow for conservation of remaining tooth structure to an ext ent never before available. In the near future physical properties wil l be improved still further, and the use of these cements will expand considerably.