Radiopaque dental composition

1. A dental composition comprising:

a resin matrix comprising:

cross-linkable component(s) as Component A characterized by the Formula (I):

wherein:

a is an integer selected from 0 and 1,

A is selected from:

B is selected from:

*—(CH 2 ) b —*, *—(CH 2 —CH 2 —O—CH 2 —CH 2 )—*, *—(CH 2 —CH 2 —O—CH 2 —CH 2 —CH 2 )—*, *—(CH 2 —CH 2 —CH 2 —O—CH 2 —CH 2 —CH 2)— *,

b is an integer selected from 2 to 6,

B′ being selected from *—(CH 2 ) b′ —*, *—(CH 2 —CH 2 —O—CH 2 —CH 2 )—*,

b′ is an integer selected from 2 to 6,

R is H or methyl,

X is selected from H, methyl, ethyl, hexyl, tert-butyl, and Br,

Y is H and Br,

“*” representing those site(s) of a moiety of the monomer, where that moiety is bonded to another moiety of the monomer;

ethylenically unsaturated component(s) with acidic moiety as Component B; and

an initiator system comprising:

photoinitiator(s) as Component C, and

reducing agent(s) as Component D.

2. The dental composition of claim 1 , for use as self-etching, self-adhesive bonding composition, restoration primer or dental sealant.

3. The dental composition of claim 1 , being characterized by the following features alone or in combination:

viscosity: 0.01 to 3 Pa*s at 23° C.;

pH-value: 0.8 to 4 if determined with wet pH-sensitive paper;

shear bond strength to enamel: at least 12 MPa according to ISO 29022 (2013-09);

shear bond strength to dentin: at least 12 MPa according to ISO 29022 (2013-09);

being x-ray visible;

being storage stable.

4. The dental composition of claim 1 , Component A being characterized by the following features alone or in combination:

molecular weight: 460 to 800 g/mol;

viscosity: 0.2 to 3 Pa*s at 23° C.;

refractive index: 1.52 to 1.57.

5. The dental composition of claim 1 , Component A being characterized by the following formula:

wherein:

each R is independently selected from H and CH 3 ;

each S is independently selected from a linear or branched C 2-3 alkylene group;

each X is independently selected from H and Br, wherein at least one X is Br; and

each n is independently an integer of 1 or 2.

6. The dental composition of claim 1 , Component B being represented by the following formula

A n BC m

wherein:

B is selected from (i) linear or branched C 1 to C 12 alkyl, optionally substituted with OH, (ii) C 6 to C 12 aryl, optionally substituted with OH, (iii) organic group having 4 to 20 carbon atoms bonded to one another by one or more ether, thioether, ester, thioester, thiocarbonyl, amide, urethane, carbonyl and/or sulfonyl linkages, each optionally substituted with OH,

A is an ethylenically unsaturated group,

C is an acidic group,

m is an integer selected from 1, 2, 3, 4, 5 and 6, and

n is an integer selected from 1, 2, 3, 4, 5, and 6,

wherein the acidic group comprises one or more carboxylic acid residues, phosphoric acid residues, phosphonic acid residues or sulphonic acid residues.

7. The dental composition of claim 1 , comprising in addition the following components alone or in combination:

filler(s) as Component E in an amount of 0 to 25 wt. %;

solvent(s) as Component F in an amount of 0 to 50 wt. %;

water as Component G in an amount of 0 to 20 wt. %;

ethylenically unsaturated monomer(s) without an acidic moiety other than Component A as Component H in an amount of 0 to 80 wt. %;

additive(s) as Component I in an amount of 0 to 5 wt. %;

wt. % with respect to the weight of the whole composition.

8. The dental composition of claim 1 , containing the components in the following amounts:

Component A: 10 to 50 wt. %,

Component B: 2 to 20 wt. %,

Component C: 0.1 to 3 wt. %,

Component D: 0.1 to 3 wt. %,

filler(s): 0 to 25 wt. %,

solvent(s): 0 to 50 wt. %,

water: 0 to 20 wt. %,

ethylenically unsaturated monomer(s) without an acidic moiety other than Component A:

0 to 40 wt. %,

additive(s): 0 to 10 wt. %,

wt. % with respect to the weight of the whole composition.

9. The dental composition of claim 1 , not comprising the following components alone or in combination:

aldehydes in an amount of more than 1 wt. %;

solvent(s) with a boiling point above 150° C. in an amount of more than 2 wt. %;

bisphenol A-glycidyl methacrylate in an amount of more than 5 or 10 wt. %;

coloured dyes or pigments which are not photobleachable in an amount of more than 1 wt. %;

fillers with an average particle size larger than 50 μm in an amount or more than 1 wt. %;

wt. % with respect to the weight of the whole composition.

10. The dental composition of claim 5 ,

wherein Component A is present in an amount of 20 to 50 wt. %,

Component B represented by the formula:

A n BC m

wherein:

B is selected from (i) linear or branched C 1 to C 12 alkyl, optionally substituted with OH, (ii) C 6 to C 12 aryl, optionally substituted with OH, (iii) organic group having 4 to 20 carbon atoms bonded to one another by one or more ether, thioether, ester, thioester, thiocarbonyl, amide, urethane, carbonyl and/or sulfonyl linkages, each optionally substituted with OH,

A is an ethylenically unsaturated group,

C is an acidic group,

m is an integer selected from 1, 2, 3, 4, 5 and 6,

n is an integer selected from 1, 2, 3, 4, 5 and 6,

wherein the acidic group comprises one or more phosphoric acid residues and mixtures thereof, and

wherein Component B is present in an amount of 5 to 20 wt. %,

Component C:

being selected from components comprising an alpha di-keto moiety, an anthraquinone moiety, a thioxanthone moiety or benzoin moiety and mixtures thereof, and

being present in an amount of 0.1 to 3 wt. %,

Component D:

being selected from secondary and tertiary amines and mixtures thereof, and

being present in an amount of 0.1 to 3 wt. %,

filler(s):

being selected from submicron silica particles thereof, and

being present in an amount of 1 to 20 wt. %,

solvent(s):

being selected from alcohols, ketones, esters, ethers and mixtures thereof, and

being present in an amount of 1 to 30 wt. %,

water:

being present in an amount of 1 to 20 wt. %,

ethylenically unsaturated monomer(s) without an acidic moiety other than Component A:

being selected from non-brominated, ethylenically unsaturated component(s) without acidic moiety(s) and mixtures thereof and

being present in an amount of 10 to 40 wt. %,

additive(s):

being selected from inhibitors, retarders, stabilizers, dyes, fluoride release agents, wetting agents, antioxidants and mixtures thereof and

being present in an amount of 1 to 10 wt. %,

wt. % with respect to the weight of the whole composition.

11. The dental composition of claim 1 , for use in a process comprising the step of applying the dental composition to a dental surface and/or adhesively fixing a dental restoration to a dental surface.

12. A process of treating a surface of a dental restoration, the process comprising:

applying a dental composition of claim 1 to the surface of a dental restoration.

13. A kit of parts comprising:

a dental composition of claim 1 , and

either of the following parts alone or in combination

dental filling material;

dental milling blank;

dental cement;

hydrofluoric acid etchant;

sandblasting medium;

sandblasting device;

a dental filling material.

14. The dental composition of claim 1 , Component A being characterized by the following formula:

wherein each X is H or Br, wherein at least one X is Br.

15. The dental composition of claim 1 , wherein Component A is selected from:

and a combination thereof.

16. The dental composition of claim 1 , wherein Component A is selected from:

and a combination thereof.

17. The dental composition of claim 1 , wherein Component A is selected from:

and a combination thereof.

18. The dental composition of claim 1 , wherein Component A is a combination of:

19. A dental composition comprising:

a resin matrix comprising:

cross-linkable component(s) as Component A;

ethylenically unsaturated component(s) with acidic moiety as Component B; and

an initiator system comprising:

photoinitiator(s) as Component C, and

reducing agent(s) as Component D,

wherein Component A is characterized by one or more of the following formulae:

20. The dental composition of claim 19 , wherein Component A is the combination of the following formulae: