Abstract
The purpose of this study was (1) to compare the fluoride release profile of an experimental composite to commercial GICs, resin-modified GICs, and composite resins; (2) to assess the fluoride release process.
Commercial materials (
n=3) were prepared according to manufacturers' directions. The experimental composite (
n=3) consisted of 78
wt% filler and 22
wt% resin. The resin consisted of 19
wt% BisGMA, 38
wt% UDMA, 19
wt% TEGDMA, and 24
wt% HEMA. Disc specimens were placed into 25
ml of deionized water in sealed polyethylene vials and shaked at 1.4
Hz at 37
°C. Fluoride release was measured using a fluoride-ion specific electrode at different time intervals up to 284 days.
The fluoride release rate of the experimental composite demonstrated the highest rate of release within the first day (
p=0.05), but decreased significantly by day 7. Release rates of the commercial glass-ionomer cements and resin-modified glass-ionomer cements thereafter were significantly higher than the experimental and commercial composites at
p=0.05. Among the materials studied, cumulative fluoride release is adequately described by a two-term equation consisting of an initial fluoride release via a rapid dissolution process followed by a long-term diffusive release.
An increase in the hydrophilicity of the polymer matrix through the introduction of HEMA improved the fluoride release over the short term during which dissolution occurs. Such a release behavior could be beneficial if it results in a fluoride reservoir that could be maintained by a prolonged slower release thereafter.