Dual-Curing Dental Compositions with High Stability

Abstract

Two-part dual-curing dental compositions containing a hydroperoxide, a thiourea derivative and an acetylacetonate salt as redox radical initiator system, are provided. The dental compositions may contain an acidic monomer for use as a self-adhesive cement. The dental compositions possess enhanced shelf-life stability for working/setting time, bonding strength, color stability, slump, flexural strength/modulus, and when kept at 50° C. for more than 16 weeks.

We claim: 
     
         1 . A two-part curable dental composition comprising
 a) a first part comprising
 a polymerizable monomer having an acidic functional group, 
 a first polymerizable monomer having no acidic functional group, and 
 a hydroperoxide compound; and 
   b) a second part comprising
 a second polymerizable monomer having no acidic functional group, 
 a composition comprising a fluoro or trifluoromethyl substituted phenylthiourea, and 
 an acetylacetonate compound, 
   wherein the first part, the second part, or both, optionally comprise a filler; and   wherein the dental composition, stored for at least 16 weeks at 50° C.: (i) is curable upon mixing the first paste and the second paste, (ii) has a working time and a setting time of at least 90 seconds and less than 10 minutes, and (iii) has a delta E of less than 3.   
     
     
         2 . The two-part dental composition of  claim 1 , where the first part is a paste and the second part is a paste. 
     
     
         3 . The two-part dental composition of  claim 1 , wherein the polymerizable monomer having an acidic functional group comprises methacryloyloxydecyl phosphate, glyceryldimethacrylate phosphate, hydroxyethylmethacrylate phosphate, phenyl methacryloxyethyl phosphate (phenyl-P), dipentaerythritol pentaacrylate phosphate, or bis(hydroxyethylmethacrylate) phosphate, or a combination thereof. 
     
     
         4 . The two-part dental composition of  claim 1 , wherein the polymerizable monomer having an acidic functional group comprises 4-methacryloxyethyl trimellitic acid, or 10-methacryloxydecyl malonic acid, or a combination thereof. 
     
     
         5 . The two-part dental composition of  claim 1 , wherein the polymerizable monomer having an acidic functional group has a concentration of 1% by weight to 20% by weight of the first part. 
     
     
         6 . The two-part dental composition of  claim 1 , wherein the hydroperoxide compound comprises cumene hydroperoxide, t-butyl hydroperoxide, p-diisopropylbenzene hydroperoxide, t-amyl hydroperoxide, pinane hydroperoxide, p-menthane hydroperoxide, or 1,1,3,3-tetramethylbutyl hydroperoxide, or a combination thereof. 
     
     
         7 . The two-part dental composition of  claim 1 , wherein the hydroperoxide compound has a concentration of 0.1% by weight to 5% by weight of the first part. 
     
     
         8 . The two-part dental composition of  claim 1 , wherein the composition comprising fluoro or trifluoromethyl substituted phenylthiourea comprises (2,3-difluorophenyl)-thiourea, [3-(trifluoromethyl)-phenyl]thiourea, or [4-(trifluoromethyl) phenyl]thiourea, or a combination thereof. 
     
     
         9 . The two-part dental composition of  claim 1 , wherein the second part comprises vanadyl acetylacetonate, vanadium(III) acetylacetonate or copper(II) acetylacetonate, or a combination thereof. 
     
     
         10 . The two-part dental composition of  claim 1 , wherein the first part comprises a filler, and the second part comprises a second filler that is different from the first filler. 
     
     
         11 . The two-part dental composition of  claim 1 , wherein the composition is a dual-curing composition and the second part further comprises a photoinitiator. 
     
     
         12 . The two-part dental composition of  claim 1 , wherein the composition further comprises a stabilizer. 
     
     
         13 . A curable dental composition comprising
 a) a first paste comprising:
 at least one polymerizable monomer having an acidic functional group, 
 at least one polymerizable monomer having no acidic functional group, and 
 a hydroperoxide compound; and 
   b) a second paste comprising
 at least one polymerizable monomer having no acidic functional group, 
 a composition comprising (difluorophenyl)thiourea or [(trifluoromethyl)phenyl]thiourea, 
 a photoinitiator, and 
 an acetylacetonate compound, 
   wherein the dental composition further comprises a filler; and   wherein the dental composition, stored for at least 16 weeks at 50° C.: (i) is curable upon mixing the first paste and the second paste, (ii) has a working time and a setting time of at least 90 seconds and less than 10 minutes, and (iii) has a delta E of less than 3.   
     
     
         14 . The curable dental composition of  claim 13 , comprising (2,3-difluorophenyl)-thiourea, [3-(trifluoromethyl)phenyl]thiourea, or [4-(trifluoromethyl)phenyl]-thiourea, or combinations thereof. 
     
     
         15 . The curable dental composition of  claim 13 , wherein the at least one polymerizable monomer having an acidic functional group comprises a phosphate group, a carboxylic acid group, or sulfonic acid group.