Bioreactive material for a prosthesis or composite implants

A sintered, shaped long-life dental implant or osseous prosthesis configured to be implanted into a human or animal body with chemical bonding to bone tissue, said implant or prosthesis resulting from sintering of a shaped mass of bioglass particles at or above a temperature softening the bioglass particles, to form a bioreactive material having a composition comprising, by weight:

• ______________________________________ 5-14% Na.sub.2 O;
• 0-12% P.sub.2 O.sub.5 ;
• 49-57% SiO.sub.2 ;
• ______________________________________
• balance, less than or equal to 33% CaO+CaF.sub.2, said bioreactive material containing 0.5-7% CaF.sub.2 ;
• and
• said implant or prosthesis having limited reactivity with bone tissue and a coefficient of expansion less than 10.sup.-5 K.sup.-1 from 0.degree. to 100.degree. C.