Dental compositions comprising ethylenically unsaturated addition-fragmentation agent

1. A dental composition comprising:

an addition-fragmentation agent of the formula:

wherein

R 1 , R 2 and R 3 are each independently Z m -Q-, a (hetero)alkyl group or a (hetero)aryl group with the proviso that at least one of R 1 , R 2 and R 3 is Z m -Q-;

Q is a linking group have a valence of m+1;

Z is an ethylenically unsaturated polymerizable group;

m is 1 to 6;

each X 1 is independently —O— or —NR 4 —, where R 4 is H or C 1 -C 4 alkyl; and

n is 0 or 1;

at least one monomer comprising at least two ethylenically unsaturated group; and

inorganic oxide filler.

2. The dental composition of claim 1 wherein the addition-fragmentation agent comprises at least two ethylenically unsaturated terminal groups.

3. The dental composition of claim 1 wherein the ethylenically unsaturated groups are (meth)acrylate groups.

4. The dental composition of claim 1 wherein Z comprises a vinyl, vinyloxy, (meth)acryloxy, (meth)acrylamido, styrenic and acetylenic functional groups.

5. The dental composition of claim 1 wherein Z is selected from:

wherein R 4 is H or C 1 -C 4 alkyl.

6. The dental composition of claim 1 wherein Q is selected from —O—, —S—, —NR 4 —, —SO 2 —, —PO 2 —, —CO—, —OCO—, —R 6 —, —NR 4 —CO—NR 4 —, NR 4 —CO—O—, NR 4 —CO—NR 4 —CO—O—R 6 —, —CO—NR 4 —R 6 —, —R 6 —CO—O—R 6 —, —O—R 6 —, —S—R 6 —, —NR 4 —R 6 —, —SO 2 —R 6 —, —PO 2 —R 6 —, —CO—R 6 —, —OCO—R 6 —, —NR 4 —CO—R 6 —, NR 4 —R 6 —CO—O—, and NR 4 —CO—NR 4 —,

wherein each R 4 is hydrogen, a C 1 to C 4 alkyl group, or aryl group, each R 6 is an alkylene group having 1 to 6 carbon atoms, a 5- or 6-membered cycloalkylene group having 5 to 10 carbon atoms, or a divalent arylene group having 6 to 16 carbon atoms, with the proviso that Q-Z does not contain peroxidic linkages.

7. The dental composition of claim 1 wherein Q is an alkylene or hydroxyl-substituted alkylene or aryloxy-substituted alkylene or alkoxy-substituted alkylene.

8. The dental composition of claim 1 wherein Q is an alkylene of the formula —C r H 2r —, where r is 1 to 10.

9. The dental composition of claim 1 wherein Q is a hydroxyl-substituted alkylene.

10. The dental composition of claim 1 wherein Q is —CH 2 —CH(OH)—CH 2 —.

11. The dental composition of claim 1 wherein Q is an aryloxy-substituted alkylene.

12. The dental composition of claim 1 wherein R 5 is an alkoxy-substituted alkylene.

13. The dental composition of claim 1 wherein R 1 —X 1 — groups (and optionally R 2 —X 2 — groups) is selected from H 2 C═C(CH 3 )C(O)—O—CH 2 —CH(OH)—CH 2 —O—, H 2 C═C(CH 3 )C(O)—O—CH 2 —CH(O—(O)C(CH 3 )═CH 2 )—CH 2 —O—, H 2 C═C(CH 3 )C(O)—O—CH(CH 2 OPh)—CH 2 —O—, H 2 C═C(CH 3 )C(O)—O—CH 2 CH 2 —N(H)—C(O)—O—CH(CH 2 OPh)—CH 2 —O—, H 2 C═C(CH 3 )C(O)—O—CH 2 —CH(O—(O)C—N(H)—CH 2 CH 2 —O—(O)C(CH 3 )C═CH 2 )—CH 2 —O—, H 2 C═C(H)C(O)—O—(CH 2 ) 4 —O—CH 2 —CH(OH)—CH 2 —O—, H 2 C═C(CH 3 )C(O)—O—CH 2 —CH(O—(O)C—N(H)—CH 2 CH 2 —O—(O)C(CH 3 )C═CH 2 )—CH 2 —O—, CH 3 —(CH 2 ) 7 —CH(O—(O)C—N(H)—CH 2 CH 2 —O—(O)C(CH 3 )C═CH 2 )—CH 2 —O—, H 2 C═C(H)C(O)—O—(CH 2 ) 4 —O—CH 2 —CH(—O—(O)C(H)═CH 2 )—CH 2 —O— and H 2 C═C(H)C(O)—O—CH 2 —CH(OH)—CH 2 —O—, H 2 C═C(H)C(O)—O—(CH 2 ) 4 —O—CH 2 —CH(—O—(O)C(H)═CH 2 )—CH 2 —O—, and CH 3 —(CH 2 ) 7 —CH(O—(O)C—N(H)—CH 2 CH 2 —O—(O)C(CH 3 )C═CH 2 )—CH 2 —O—.

14. The dental composition of claim 1 wherein the ethylenically unsaturated groups of the monomer are (meth)acrylate groups.

15. The dental composition of claim 1 wherein the monomer is an aromatic monomer having a refractive index of at least 1.50.

16. The dental composition of claim 1 wherein the monomer is a low volume shrinkage monomer.

17. The dental composition of claim 1 wherein the monomer is an isocyanurate monomer, a tricyclodecane monomer, or a mixture thereof.

18. The dental composition of claim 1 wherein the hardened dental composition exhibits a stress deflection no greater than 2.0.

19. The dental composition of claim 1 wherein the dental composition comprises at least one (meth)acrylate monomer selected from ethoxylated bisphenol A dimethacrylate (BisEMA6), 2-hydroxyethyl methacrylate (HEMA), bisphenol A diglycidyl dimethacrylate (bisGMA), urethane dimethacrylate (UDMA), triethlyene glycol dimethacrylate (TEGDMA), glycerol dimethacrylate (GDMA), ethylenegylcol dimethacrylate, neopentylglycol dimethacrylate (NPGDMA), polyethyleneglycol dimethacrylate (PEGDMMA), and mixtures thereof.

20. The dental composition of claim 1 wherein the filler inorganic oxide filler comprises nanoparticles.

21. The dental composition of claim 20 wherein the inorganic nanoparticles comprise silica, zirconia, or mixtures thereof.

22. The dental composition of claim 20 wherein the inorganic nanoparticles are in the form of nanoclusters.

23. A method of treating a tooth surface, the method comprising

providing a hardenable dental composition of claim 1 comprising an addition-fragmentation agent,

placing the dental composition on a tooth surface; and

hardening the hardenable dental composition.

24. The method of claim 23 wherein the dental composition further comprises at least one ethylenically unsaturated monomer with acid functionality.

25. A dental article comprising the hardenable dental composition of claim 22 at least partially hardened.

26. A method of treating a tooth surface, the method comprising providing an at least partially hardened dental article according to claim 25 , adhering the dental article on a tooth surface in the mouth of a subject.

27. The dental composition of claim 1 further comprising a redox hardening agent.