Abstract
ObjectivesTo study the fluoride uptake and release properties of glass carbomer dental cements and compare them with those of conventional and resin-modified glass ionomers.Materials and MethodsThree materials were used, as follows: glass carbomer (Glass Fill), conventional glass ionomer (Chemfil Rock) and resin-modified glass ionomer (Fuji II LC). For all materials, specimens (sets of six) were matured at room temperature for time intervals of 10 minutes, 1 hour and 6 weeks, then exposed to either deionized water or sodium fluoride solution (1000 ppm in fluoride) for 24 hours. Following this, all specimens were placed in deionized water for additional 24 hours and fluoride release was measured.ResultsStorage in water led to increase in mass in all cases due to water uptake, with uptake varying with maturing time and material type. Storage in aqueous NaF led to variable results. Glass carbomer showed mass losses at all maturing times, whereas the conventional glass ionomer gained mass for some maturing times, and the resin-modified glass ionomer gained mass for all maturing times. All materials released fluoride into deionized water, with glass carbomer showing the highest release. For both types of glass ionomer, uptake of fluoride led to enhanced fluoride release into deionized water. In contrast, uptake by glass carbomer did not lead to increased fluoride release, although it was substantially higher than the uptake by both types of glass ionomer.ConclusionsGlass carbomer resembles glass ionomer cements in its fluoride uptake behavior but differs when considering that its fluoride uptake does not lead to increased fluoride release.
Highlights
Glass ionomer cements are materials that have several applications in restorative dentistry, including functioning as liners and bases, full restoratives, pitand-fissure sealants, and adhesives for the fixation of orthodontic brackets.[1-3]Bioactivity is an important feature of these materials, a phenomenon that has appeared in several observations
For the specimens exposed to deionized water only, these results represent the sum of the release in the two 24-hour periods in fresh deionized water volumes. These results show that glass carbomer had the highest level of fluoride release but that there was no increase in fluoride release due to exposure to fluoride solution, a result that strongly contrasts with those for the two glass ionomers
Chemfil Rock maturated for 10 minutes presented 36.5 ppm fluoride release after exposure to NaF solution, which was 36.5 – 5.3 = 31.2 ppm more than for specimens exposed to deionized water
Summary
Glass ionomer cements are materials that have several applications in restorative dentistry, including functioning as liners and bases, full restoratives, pitand-fissure sealants, and adhesives for the fixation of orthodontic brackets.[1-3]Bioactivity is an important feature of these materials, a phenomenon that has appeared in several observations. At the bottom of pits and fissures, the morphology of the glass ionomer changes and a structure is formed, which is reported to be “enamel-like”.7. These features have been exploited in a new type of glass ionomer material known as glass carbomerTM. This material is formulated with hydroxyapatite as a secondary filler,[8] previous reports suggested that the filler was fluorapatite.[9,10]. A final novel component of glass carbomer is a silicone oil consisting of linear polydimethylsiloxane molecules with functional hydroxyl groups These hydroxyl groups can form hydrogen bonds with other cement components, preventing the silicone oil from leaching from the cement after being set. The precise function of silicone oil is not clear, studies suggest the possibility that it is a toughening agent for what would otherwise be an extremely brittle material.[12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
