RESIN-MODIFIED GLASS-IONOMERS

This paper reviews the current status of resin-modified glass-ionomers and presents the results of recent findings of research in some key a reas. The debate on nomenclature pertaining to these products is perce ived as being pointless and the need for application-based ISO standar ds is raised. Setting characteristics are similar in many respects to those of light-activated composites, although some products have limit ed working time due to the influence of the acid-base setting reaction and sensitivity to ambient light. Water absorption and swelling are g enerally very high. The clinical significance of swelling after water exposure is unknown. Mechanical properties of most materials lie betwe en those of the composites and conventional glass-ionomers depending u pon the resin content of the matrix phase of the set material. Some pr oducts demonstrate an inherent adhesion to enamel, although etching ma y be required in order to make the bond clinically effective. Bonding to dentine is probably through a more complex mechanism than that invo lved with conventional glass-ionomers. Conditioning and priming of den tine is often advocated. Fluoride release rates and their clinical sig nificance is an area which requires clarification and standardization. The key factor appears to be the frequency with which the storage wat er is changed. Equilibration is reached within minutes for some materi als and their true fluoride-releasing potential can only be judged und er dynamic test conditions. (C) 1998 Published by Elsevier Science Ltd . All rights reserved.