The interaction of lactic acid-glass cements with aqueous solutions.

Cylindrical specimens of experimental lactic acid-glass cements (6mm high x 4mm diameter) were prepared, matured at 37 degrees C for one week sealed in their molds, then exposed either to water (pH 6.6) or aqueous lactic acid (pH 2.7) for a further week. Solutions were analyzed by ICP-OES and their pH values recorded. In both solutions, cement specimens were found to release aluminum together with smaller amounts of calcium, sodium, silicon and phosphorus. They also formed soft gels that ICP-OES analysis showed were comprised mainly of aluminum and phosphorus species. These dissolution and gelation processes were accompanied by changes in the pH of the storage media (water to pH 4.9; lactic acid to 4.2). It is concluded that further work is necessary in order to fully characterize the species of aluminum released from these cements.