This invention is directed to lithium disilicate (Li.sub.2 Si.sub.2
O.sub.5) based glass-ceramics comprising silica, lithium oxide, alumina,
potassium oxide and phosphorus pentoxide. The glass-ceramics are useful in
the fabrication of single and multi-unit dental restorations (e.g.
anterior bridges) made by heat pressing into refractory investment molds
produced using lost wax techniques. The glass-ceramics have good
pressability, i.e., the ability to be formed into dental articles by
heat-pressing using commercially available equipment. In accordance with
one embodiment directed to the process of making the glass-ceramics, the
compositions herein are melted at about 1200 .degree. to about 1600
.degree. C., thereafter cast into steel molds in the shape of cylindrical
blanks (pellets), or alternately, cooled to the crystallization
temperature. The resulting glass blank are heat-treated to form
glass-ceramic blanks via a one or two step heat-treatment cycle preferably
in the temperature range of about 400 .degree. to about 1100 .degree. C.
The resulting glass-ceramic pressable pellets and/or blanks of desired
shapes, sizes and structures are later pressed into dental restorations.
Alternatively, instead of forming into pressable pellets or blanks, the
pulverized powder is used to form a dental restoration using the
refractory die technique or platinum foil technique.
