A dental composition comprising a polymerizable resin comprising ethylenically unsaturated groups； a thermally activated initiator dissolved in the resin； and an inorganic filler combined with the resin in an amount greater than about 60 percent by weight based upon the weight of the composition； wherein the initiator is activated at a temperature of about 100 to about 150° C. to provide free radicals； and wherein the filler has a surface area of at least about 65 square meters per gram filler； a dental mill block comprising the thermally cured composition, a method of manufacturing the dental mill block, and a kit comprising a plurality of the mill blocks are provided.
