Abstract: A process for preparing particulate, bioactive and resorbable biosilicates from vitreous plates or frits is described, which comprises thermally treating the vitreous plates or frits in a single or in two thermal treatment steps, at controlled temperatures and times, and then milling the crystallized glass to obtain crystallized bioactive or resorbable biosilicate powders of desired bioactivity, free from sharp, cutting edges, that in contact with body fluids produce a teeth-restoring hydroxycarbonate apatite layer or can be gradually replaced by dental tissue and resorbed. Alternatively, a vitreous powder is first obtained, which is then thermally treated to yield the crystalline, bioactive or resorbable powder, which is free from sharp cutting edges.