Comparison of ion release from a glass ionomer cement as a function of themethod of incorporation of added ions

The addition of potassium and fluoride ions to a water-admixed glass ionome r cement initially free from either ion was accomplished either by addition via the mixing water or by immersing mixed set cement in a solution of the ions in water. In both cases the aqueous concentration of ions was the sam e. The release of both potassium and fluoride was measured for 500 days. Io n release from immersed specimens was some 20-fold higher than from the oth er method indicating enhanced concentration of ions inside the cement. This calculation assumes that the ions resided in the aqueous phase. Ions added by mixing appeared to follow the release pattern shown by glass ionomers c ontaining intrinsic fluoride; ions added by immersion did not. As specimens matured the amount which could be taken up by immersion was reduced. Potas sium release was still continuing at 500 days whereas fluoride release was complete. (C) 1999 Elsevier Science Ltd. All rights reserved.