Chlorhexidine release from an experimental glass ionomer cement

Glass ionomer cements (GIC) can potentially be used as matrices for the slow release of active species, as has been shown previously for fluoride ions. This study investigated the use of an experimental GIC as a carrier for the release of chlorhexidine acetate (CHA) at included concentrations ranging from 0.5% to 13.0% of CHA by weight. Release into water was examined using high-performance liquid chromatography. All measurable chlorhexidine was released within 22 h1/2, however this was less than 10% of the total mass incorporated in the specimens. An increased percentage of CHA incorporated into the powder gave an increased release into the surrounding water. The bulk of the CHA was retained within the cement. For comparison, the surface chemistry of a CHA-containing GIC was examined using X-ray photoelectron spectroscopy before and after prolonged immersion in water. This confirmed retention of a large amount of CHA. Spectra after leaching appeared very similar to those from a CHA-free GIC after immersion in a CHA solution. In order to explore the effect of CHA-inclusion on the cement properties, compressive strengths, working and setting times were also measured. In general, compressive strengths were found to be decreased in direct proportion to the quantity of CHA added, while working and setting times increased.