Effects of surface pre-reacted glass-ionomer fillers on mineral induction by phosphoprotein.

The aim of this study was to evaluate the mineralizing potential of ions released from surface pre-reacted glass-ionomer (S-PRG) fillers on mineral induction by phosphoprotein in vitro. Phosvitin was used as a model of dentin phosphoprotein in this study. Phosvitin was immobilized on agarose beads with divinyl sulfone. Five aliquots of phosvitin-immobilized agarose beads were incubated in control or experimental mineralizing solution. The experimental mineralizing solutions were made from eluates of resin filled with S-PRG fillers. The beads were incubated at 37°C in a shaking water bath, and aliquots were taken at several time points during the incubation. Then the beads were analyzed for calcium by atomic absorption spectrometry. Phosvitin-immobilized agarose beads induced mineral formation after incubation for 5.3h in the metastable solution without ions eluted from S-PRG fillers. Undiluted eluates significantly reduced mineral induction time. SEM observation and X-ray diffraction revealed larger apatite crystals on the beads incubated with eluates of S-PRG fillers than with the control. S-PRG fillers may play a role in mineral induction.