Dental compositions, mill blocks, and methods

Abstract

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.

What is claimed is: 
     
         1 . A dental composition comprising:
 a polymerizable resin comprising an ethylenically unsaturated group;   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.   
     
     
         2 . A dental mill block comprising a thermally cured composition comprising:
 a polymerizable resin which is a free-radial initiated addition polymerization product of a polymerizable resin comprising methacryloyl groups; and   an inorganic filler dispersed in the polymerized resin;   wherein the inorganic filler has a surface area of at least 65 square meters per gram filler and is present in the polymerized resin in amount greater than 60 percent by weight based upon the weight of the composition; and   wherein the composition is thermally cured by thermally activating an initiator dissolved in the polymerizable resin, the initiator being activated at a temperature of about 100 to about 150° C.   
     
     
         3 . A method of manufacturing a dental mill block, the method comprising:
 providing a composition comprising:
 a polymerizable resin comprising an ethylenically unsaturated group; 
 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; 
   shaping the composition into a desired mill block configuration; and   thermally curing the composition at a temperature of about 100 to about 150° C.   
     
     
         4 . The composition of  claim 1 , the wherein the surface area of the inorganic filler is at least about 80 square meters per gram filler. 
     
     
         5 . The composition of  claim 1 , wherein the filler is present in an amount of at least about 75 percent by weight based upon the weight of the composition. 
     
     
         6 . The composition of  claim 1 , wherein the filler is selected from the group consisting of metal oxide nanoclusters, heavy metal oxide nanoparticles, non-heavy metal oxide nanoparticles, and a combination thereof. 
     
     
         7 . The composition of  claim 1 , wherein the initiator is selected from the group consisting of dicumyl peroxide, t-butyl peroxide, 2,5-Bis(tert-butylperoxy)-2,5-dimethylhexane; 2,5,-Bis(tert-Butylperoxy)-2,5-dimethyl-3-hexyne; Bis(1-(tert-butylperoxy)-1-methylethy)benzene; tert-butyl peracetate; tert-butyl peroxybenzoate; cumene hydroperoxide; 2,4-pentanedione peroxide; peracetic acid, and combinations thereof. 
     
     
         8 . The composition of  claim 7 , the wherein the initiator is dicumyl peroxide. 
     
     
         9 . The composition of  claim 1 , wherein the initiator is present in the composition in an amount of about 0.2 to about 3 percent based upon the weight of the polymerizable resin. 
     
     
         10 . The composition of  claim 1  wherein the polymerizable resin comprises a compound selected from the group consisting of 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane (Bis-GMA), triethyleneglycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA), 4 to 10 mole ethoxylated Bisphenol-A dimethacrylate (Bis-EMA), dimethacrylates of polyethylene glycols of 200 to 1000 weight average molecular weight, glycerol dimethacrylate, 1,3-propanediol dimethacrylate, and a combination thereof. 
     
     
         11 . The composition of  claim 1 , wherein when thermally cured, the composition has a flexural strength of at least 180 MPa according to Test Method I. 
     
     
         12 . The composition of  claim 1 , wherein the polish retention of the composition when thermally cured is at least 90 gloss units (G F ) after 3000 brush strokes according to Test Method II. 
     
     
         13 . The composition of  claim 1 , wherein the wear loss of the composition when thermally cured is less than 7 microns after 200,000 cycles according to Test Method III. 
     
     
         14 . A kit comprising a plurality of mill blocks according to  claim 2 . 
     
     
         15 . The composition of  claim 1  wherein the composition is used to form an implant abutment. 
     
     
         16 . The mill block of  claim 2 , wherein the mill block is formed into an implant abutment.