Curable zirconia adhesive compositions for dental restorations

A dental adhesive system comprising:

• a zirconia-based ceramic;
• and
• an adhesive composition applied to the surface of the zirconia-based ceramic, comprising:
• (a) a first acidic monomer having an ethylenically unsaturated polymerizable group of the general formula CH2═CX—C(O)—R wherein X is hydrogen, methyl or a lower alkyl group, and wherein R is a phosphoric acid group or phosphonic acid group having the general formula —OP(O)(OH)2, —OP(O)(OH), —C—P(O)(OH)2 or —C—P(O)(OH), the first acidic monomer comprising about 1% to about 5% of the composition by weight;
• (b) a second acidic monomer having an ethylenically unsaturated polymerizable group of the general formula CH2═CX—C(O)—R1 wherein X is hydrogen, methyl or a lower alkyl group, and wherein R1 comprises a carboxylic acid group having the general formula —C(O)OH, the second acidic monomer comprising about 2% to about 10% of the composition by weight;
• (c) at least one comonomer selected from the group consisting of 2-hydroxyethyl methacrylate, bisphenol A diglycidyl methacrylate, triethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, ethoxylated bisphenol A diglycidyl methacrylate, and urethane dimethacrylate;
• (d) an initiator comprising at least one photosensitive ketone and at least one tertiary amine;
• and
• (e) wherein the ratio of the first acidic monomer to the second acidic monomer is between about 1:10 and 3:1, respectively.

A method of bonding zirconia to a surface, comprising:

• (a) providing a first acidic monomer having an ethylenically unsaturated polymerizable group of the general formula CH2═CX—C(O)—R wherein X is hydrogen, methyl or a lower alkyl group, and wherein R is a phosphoric acid group or phosphonic acid group having the general formula —OP(O)(OH)2, —OP(O)(OH), —C—P(O)(OH)2 or —C—P(O)(OH), the first acidic monomer comprising about 1% to about 5% of the provided materials by weight;
• (b) providing a second acidic monomer having an ethylenically unsaturated polymerizable group of the general formula CH2═CX—C(O)—R1 wherein X is hydrogen, methyl or a lower alkyl group, and wherein R1 comprises a carboxylic acid group having the general formula —C(O)OH, the second acidic monomer comprising about 2% to about 10% of the provided materials by weight;
• (c) providing at least one comonomer selected from the group consisting of 2-hydroxyethyl methacrylate, bisphenol A diglycidyl methacrylate, triethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, ethoxylated bisphenol A diglycidyl methacrylate, and urethane dimethacrylate;
• (d) providing an initiator comprising at least one photosensitive ketone and at least one tertiary amine;
• (e) combining all provided materials and applying those materials to a zirconia dental appliance;
• and
• (f) polymerizing the combined materials applied to the zirconia dental appliance such that the initial bond between the polymerized materials and the zirconia is at least about 10 MPa as measured with the #5 gel cap method.

A dental restoration comprising:

• a zirconia based restoration having a surface prepared by application of an adhesive comprising,
• (a) a first acidic monomer having an ethylenically unsaturated polymerizable group of the general formula CH2═CX—C(O)—R wherein X is hydrogen, methyl or a lower alkyl group, and wherein R comprises a phosphoric acid group or phosphonic acid group having the general formula —OP(O)(OH)2, —OP(O)(OH), —C—P(O)(OH)2 or —C—P(O)(OH), the first acidic monomer comprising about 1% to about 5% of the adhesive by weight;
• and
• (b) a second acidic monomer having an ethylenically unsaturated polymerizable group of the general formula CH2═CX—C(O)—R1 wherein X is hydrogen, methyl or a lower alkyl group, and wherein R1 comprises a carboxylic acid group having the general formula —C(O)OH, the second acidic monomer comprising about 2% to about 10% of the adhesive by weight;
• wherein the prepared surface of the zirconia based restoration is adhered to a tooth.