Dental compositions containing nanozirconia fillers

1. A hardenable dental composition comprising:

(a) a polyacid;

(b) an acid-reactive filler;

(c) water; and

(d) a nanozirconia filler comprising:

(i) zirconia particles having an outer surface;

(ii) a plurality of silane-containing hydrophilic molecules attached onto the outer surface of the zirconia particles; and

(iii) a plurality of silane-containing reactive molecules attached onto the outer surface of the zirconia particles.

2. The composition of claim 1 further comprising a polymerizable component.

3. The composition of claim 1 wherein the nanozireonia. filler has an average particle size of no more than 100 nanometers.

4. The composition of claim 2 wherein the polymerizable component comprises an ethylenically unsaturated compound.

5. The composition of claim 2 wherein the polymerizable component comprises an ethylenically unsaturated compound with acid functionality.

6. The composition of claim 1 wherein the polyacid comprises a polymer having a plurality of acidic repeating groups but is substantially free of polymerizable groups.

7. The composition of claim 6 further comprising a polymerizable component.

8. The composition of claim 1 , wherein the polyacid comprises a polymer having a plurality of acidic repeating groups and a plurality of polymerizable groups.

9. The composition of claim 8 further comprising a polymerizable component.

10. The composition of claim 1 wherein the acid-reactive filler is selected from the group consisting of metal oxides, glasses, metal salts, and combinations thereof.

11. The composition of claim 10 wherein the acid-reactive filler comprises a fluoroaluminosilicate (FAS) glass.

12. The composition of claim 11 wherein the composition comprises less than 50 weight percent FAS glass.

13. The composition of claim 11 wherein the composition comprises less than 30 weight percent FAS glass.

14. The composition of claim 11 wherein the composition comprises less than 20 weight percent FAS glass.

15. The composition of claim 10 wherein the acid-reactive filler comprises an oxyfluoride material.

16. The composition of claim 15 wherein at least 90% by weight of the oxyfluoride material is nanostructured.

17. The composition of claim 5 wherein the acid functionality includes an oxygen-containing acid of carbon, sulfur, phosphorous, or boron.

18. The composition of claim 5 wherein the polyacid and the ethylenically unsaturated compound with acid functionality are the same.

19. The composition of claim 2 , wherein the polymerizable component and the polyacid are the same compound.

20. The composition of claim 1 wherein the nanozirconia filler is substantially free of fumed silica and pyrogenic fillers.

21. The composition of claim 2 further comprising a redox cure system.

22. The composition of claim 2 further comprising a photoinitiator system.

23. The composition of claim 1 further comprising at least one additive selected from the group consisting of other fillers, pyrogenic fillers, fluoride sources, whitening agents, anticarics agents, remineralizing agents, enzymes, breath fresheners, anesthetics, clotting agents, acid neutralizers, chemotherapeutic agents, immune response modifiers, medicaments, indicators, dyes, pigments, tartaric acid, wetting agents, chelating agents, surfactants, buffering agents, viscosity modifiers, thixotropes, polyols, antimicrobial agents, anti-inflammatory agents, antifungal agents, stabilizers, agents for treating xcrostomia, desensitizers, and combinations thereof.

24. The composition of claim 1 , wherein the composition is selected from the group consisting of dental restoratives, dental adhesives, dental cements, cavity liners, orthodontic adhesives, dental sealants, and dental coatings.

25. The composition of claim 1 wherein the composition comprises a multi-part composition comprising a first part and a second part, wherein each part can independently be selected from the group consisting of a liquid, paste, gel, or powder.

26. A method of preparing a dental article said method comprising the steps of:

(a) providing a dental composition of claim 1 ; and

(b) hardening the dental composition to form the dental article.

27. The method of claim 26 wherein the dental article is selected from the group consisting of dental mill blanks, dental crowns, dental fillings, dental prostheses, and orthodontic devices.

28. A multi-part hardenable dental composition comprising:

(a) a first part comprising a polyacid;

(b) a second part comprising an acid-reactive filler;

(c) water present in either or both parts;

(d) an optional polymerizable component present in either or both parts; and

(e) a nanozirconia filler present in either or both parts, the zirconia filler comprising:

(i) zirconia particles having an outer surface,

(ii) a plurality of silane-containing hydrophilic molecules attached onto the outer surface of the zirconia particles, and

(iii) a plurality of silane-containing reactive molecules attached onto the outer surface of the zirconia particles.