In vitro study of remineralization of dentin: effects of ions on mineral induction by decalcified dentin matrix

We examined the effects of various ions on the mineralization of dentin matrix in vitro. Demineralized dentin matrix was incubated in a metastable calcium phosphate solution with or without silicate, fluoride, calcium, phosphate, magnesium or silver. Insoluble dentin matrix induced mineral formation after incubation for 10.2 h in the metastable solution without added ions. Silicate at 5 microM and fluoride at 40 microM significantly reduced the mineral induction time. At least 200 microM calcium or 100 microM phosphate was required to promote mineral induction. Conversely, magnesium and silver concentrations as low as 10 and 2 microM inhibited mineral induction. The mineral induced by each sample after incubation for 24 h was identified by its X-ray diffraction pattern as apatite. We concluded that silicate is a stronger inducer of remineralization of dentin matrix than fluoride, calcium or phosphate, and that magnesium and silver inhibit the induction of remineralization of dentin matrix.