Objective. The aim of this study was to determine, in vitro, the relat
ive short-and long-term fluoride release from four resin-modified glas
s ionomers (Fuji II LC, Vitremer, Enforce & Advance), a polyacid-modif
ied composite resin (Dyract compomer) and a bonding agent (OptiBond).
Methods. All the materials were prepared as outlined by the manufactur
ers. Circular discs of the materials mentioned were suspended in water
for up to 300 days and the non-cumulative 24-h fluoride release was d
etermined potentiometrically at chosen times. Results. The amounts of
fluoride released during the first day were Vitremer (1.46 mu g mm(-2)
), Advance (1.18 mu g mm(-2)), Fuji (1.08 mu g mm(-2)), Optibond (0.33
mu g mm(-2)), Dyract (0.31 mu g mm(-2)) and Enforce (0.15 mu g mm(-2)
). After the second day the sequence changed slightly and remained app
roximately the same for the rest of the 300-day period. There was also
an increase in the fluoride release during the 60-200-day period rela
tive to the previous period. Conclusion: In general the most fluoride
was released by Advance and not by Fuji II LC or Vitremer. For most ma
terials, fluoride is still released after 300 days. Furthermore, even
a thin layer of bonding agent released a relatively high amount of flu
oride (volume-wise the most) at the beginning. II is deduced that even
the release of relatively ion: amounts of fluoride may result in sign
ificant concentrations of fluoride in a microleakage gap. (C) 1998 Els
evier Science Ltd. All rights reserved.