Light-curing dental composites with increasing opacity

1. Radically polymerizable dental material which comprises

(a) 5 to 40 wt.-% of at least one polyfunctional radically polymerizable monomer,

(b) 2 to 15 wt.-% of at least one monofunctional radically polymerizable monomer,

(c) 0.1 to 3.0 wt.-% of at least one photoinitiator for the radical polymerization and 10 to 85 wt.-% of at least one filler,

characterized in that the dental material comprises at least one filler (d) and that the mixture of the monomers (a) and (b) has a refractive index of from 1.50 to 1.70 and in that the refractive index of the monomer mixture before the curing corresponds to the refractive index of the filler used or is higher by up to 0.013 and after the curing is higher than the refractive index of the filler (d) by at least 0.02, and in that the dental material in addition to the filler (d) comprises, relative to the total quantity of filler,

0 to 15 wt.-% of at least one filler (e) having a refractive index which is lower than the refractive index of the mixture of the monomers (a) and (b) by 0.02 to maximally 0.155,

0 to 10 wt.-% of at least one filler which does not scatter visible light and does not influence the translucence, and

maximally 15.5 wt.-% of filler (f) which does not fall within any of the filler categories.

2. Dental material according to claim 1 , which comprises, as component (a), at least one polyfunctional methacrylate, 1,6-bis-[2-methacryloyloxy-ethoxycarbonylamino]-2,2,4-trimethylhexane (an addition product of 2-hydroxyethyl methacrylate and 2,2,4-trimethyl-hexamethylene diisocyanate), di-, tri- or tetraethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, glycerol di- and trimethacrylate, 1,4-butanediol dimethacrylate, 1,10-decanediol dimethacrylate (D 3 MA), 1,12-dodecanediol dimethacrylate and mixtures thereof, bisphenol-A-dimethacrylate, 2,2-bis[4-(2-hydroxy-3-methacryloyloxy-propyl)phenyl]propane (an addition product of methacrylic acid and bisphenol-A-diglycidyl ether), ethoxylated or propoxylated bisphenol-A-dimethacrylate, 2-[4-(2-methacryloyloxyethoxyethoxy)phenyl]-2-[4-(2-methacryloyloxy-ethoxy)phenyl]propane), 2,2-bis[4-(2-methacryloxypropoxy)-phenyl]propane, or bis-(3-methacryloyloxymethyl)tricyclo-[5.2.1.0 2,6 ]decane or a mixture thereof.

3. Dental material according to claim 1 , which exclusively contains, as component (a) and/or component (b), monomers with a refractive index of from 1.50 to 1.70.

4. Dental material according to claim 1 , which comprises at least one low-volatile monomethacrylate, in a quantity of 5-30 wt.-%, at least one highly viscous difunctional methacrylate, in a quantity of 5-50 wt.-%, and at least one low-viscosity dimethacrylate, in a quantity of 5-30 wt.-%, wherein the percentages relate to the total mass of the monomer mixture in each case.

5. Dental material according to claim 1 , in which the refractive index of the further filler not falling within any of the categories is higher than the refractive index of the mixture of the monomers (a) and (b) by at most 0.055.

6. Dental material according to claim 1 , which comprises, as filler, a pulverulent X-ray opaque glass with an average particle size of from 0.01 to 15 μm, an X-ray opaque filler, ytterbium trifluoride, a mixed oxide of SiO 2 , ZrO 2 , ZnO and/or TiO 2 , nanoparticulate tantalum(V) oxide, barium sulfate, a mixed oxide of SiO 2 with ytterbium(III) oxide or tantalum(V) oxide, pyrogenic silica or precipitated silica, an organic polymer powder, organic-inorganic filler or a mixture thereof.

7. Dental material according to claim 1 , which comprises, as component (c),

an α-diketone, 9,10-phenanthrenequinone, 1-phenyl-propane-1,2-dione, diacetyl or 4,4′-dichlorobenzil or a derivative thereof, camphorquinone (CQ) or a derivative thereof, optionally in combination with an accelerator, or a mixture thereof and/or

an acyl- or bisacylgermanium compound and/or

an acyl- or bisacylphosphine oxide.

8. Dental material according to claim 1 , which comprises, as further component, at least one additive which is selected from stabilizers, polymerization stabilizers, dyes, antibacterial active ingredients, fluoride-ion-releasing additives, optical brighteners, fluorescent agents, UV absorbers, substances for improving the fracture toughness and/or effect agents.

9. Dental material according to claim 1 , which further comprises

(5), 0.1 to 5.0 wt.-% additive(s).

10. Process of using the dental material according to claim 1 comprising preparing a dental cement, filling composite, coating material, veneering material or bulk fill composite with the dental material and using the prepared material in a dental application.

11. Process according to claim 10 wherein the dental material is fabricated into inlays, onlays, crowns or bridges.

12. Dental material according to claim 1 , in which the further filler (e) has a refractive index of which is lower than the refractive index of the mixture of the monomers (a) and (b) by 0.03 to 0.055.

13. Dental material according to claim 1 , which comprises

(1) 5 to 40 wt.-% polyfunctional radically polymerizable monomer(s),

(2) 2 to 15 wt.-% monofunctional radically polymerizable monomer(s),

(3) 0.1 to 3.0 wt.-% photoinitiator,

(4) 10 to 85 wt.-% filler(s), and optionally

(5) 0.1 to 2.0 wt.-% additive(s).

14. Dental material according to claim 1 , which comprises

(1) 5 to 25 wt.-% polyfunctional radically polymerizable monomer(s),

(2) 3 to 10 wt.-% monofunctional radically polymerizable monomer(s),

(3) 0.1 to 2.0 wt.-% photoinitiator,

(4) 40 to 80 wt.-% filler(s), and optionally

(5) 0.2 to 1.5 wt.-% additive(s).

15. Dental material according to claim 1 , wherein the at least one monofunctional monomer component comprises a methacrylate, methyl, ethyl, 2-hydroxyethyl, butyl, benzyl, tetrahydrofurfuryl or isobornyl methacrylate, p-cumyl-phenoxyethylene glycol methacrylate (CMP-1E) or a mixture thereof.