MONOMER MIXTURE FOR THE PREPARATION OF DENTAL MATERIALS

Abstract

Monomer mixture for the preparation of dental materials, which contains at least one low-volatile monomethacrylate, at least one highly viscous polyfunctional methacrylate and at least one low-viscosity polyfunctional methacrylate.

Claims

1. A monomer mixture for the preparation of dental materials which comprises at least one low-volatile monomethacrylate, at least one highly viscous polyfunctional methacrylate and at least one low-viscosity polyfunctional methacrylate.

2. The monomer mixture according to claim 1, in which the low-volatile monomer(s) has/have a boiling point >150 C. at normal pressure, the highly viscous monomer(s) has/have a viscosity >5 Pa s (measured using a capillary viscometer at 25 C.) and the low-viscosity monomer(s) has/have a viscosity <300 mPa s (measured using a rotating viscometer at 25 C.).

3. The monomer mixture according to claim 1, which comprises from 2 to 50 wt.-% of at least one low-volatile monomethacrylate; from 5 to 65 wt.-% of at least one highly viscous polyfunctional; and from 5 to 55 wt.-%, of a low-viscosity polyfunctional methacrylate.

4. The monomer mixture according to claim 1, which comprises as a highly viscous dimethacrylate, TMX-UDMA (an addition product of HEMA and hydroxypropyl methacrylate (HPMA) with ,,,-tetramethyl-m-xylylene diisocyanate (TMXDI)) and/or 1,6-bis-[2-methacryloyloxyethoxycarbonylamino]-2,4,4-trimethylhexane (UDMA), as a low-viscosity dimethacrylate, bismethacryloyloxymethyltricyclo[5.2.1.]decane (TCDMA), glycerol dimethacrylate (GDMA) and/or decanediol-1,10-dimethacrylate (D3MA) and as a low-volatile monomethacrylate, p-cumylphenoxyethylene glycol methacrylate (CMP-1E).

5. The monomer mixture according to claim 4, which comprises 20 wt.-% CMP-1E, 20 wt.-% GDMA, 20 wt.-% TMX-UDMA, 25 wt.-% UDMA and 15 wt.-% D3MA.

6. The monomer mixture according to claim 1, which does not contain any TEGDMA and also does not contain any bis-GMA.

7. The monomer mixture according to claim 1, which additionally comprises an initiator for the radical polymerization comprising a combination of a thiourea derivative and a bisacyldialkylgermanium compound.

8. The monomer mixture according to claim 7, which comprises as the thiourea derivative, methyl, ethyl, allyl, butyl, hexyl, octyl, benzyl, 1,1,3-trimethyl, 1,1-diallyl, 1,3-diallyl, 1-(2-pyridyl)-2-thiourea, acetyl, propanoyl, butanoyl, pentanoyl, hexanoyl, heptanoyl, octanoyl, nonanoyl, decanoyl, benzoyl thiourea or a mixture thereof.

9. The monomer mixture according to claim 8, which comprises as the bisacyldialkylgermanium compound, bisbenzoyldiethylgermanium, bisbenzoyldimethylgermanium, bisbenzoyldibutylgermanium, bis(4-methoxybenzoyl)dimethylgermanium, bis(4-methoxybenzoyl)diethylgermanium or a mixture thereof.

10. The monomer mixture according to claim 9, which additionally comprises a peroxide or a hydroperoxide.

11. The monomer mixture according to claim 10, which comprises as hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, t-butyl hydroperoxide, cumene hydroperoxide, pinane hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, t-amyl hydroperoxide or a mixture thereof.

12. The monomer mixture according to claim 1, which additionally comprises organic or inorganic particulate filler.

13. The monomer mixture according to claim 12, which only comprises filler with a maximum particle size of less than 600 nm.

14. The monomer mixture according to claim 1, which comprises (a) 12-75 wt. % of the monomer mixture, (b) 20-85 wt. % filler(s), (c) 0.05-4 wt.-% initiator for the radical polymerization and optionally (d) 0.1-5.0 wt.-% additive(s).

15. Method of using the monomer mixture according to claim 1 as dental cement, filling composite, coating material, veneering material, as materials for preparing inlays, onlays, crowns or bridges comprising preparing the ingredients according to claim 3 and applying the ingredients as a dental cement, filling composite, coating material, veneering material, inlay, onlay, crown or bridge.

16. The monomer mixture according to claim 1, which comprises from 5 to 45 wt.-% of at least one low-volatile monomethacrylate; from 8 to 60 wt.-% of at least one highly viscous polyfunctional methacrylate; and from 10 to 50 wt.-% of a low-viscosity polyfunctional, methacrylate.

17. The monomer mixture according to claim 1, which comprises from 10 to 30 wt.-% of at least one low-volatile monomethacrylate; from 25 to 50 wt.-% of at least one highly viscous difunctional, methacrylate; and from 20 to 45 wt.-% of a low-viscosity difunctional methacrylate.

18. The monomer mixture according to claim 1, which comprises (a) 19-56 wt.-% of the monomer mixture, (b) 40-80 wt.-% filler(s), (c) 0.1-2.0 wt.-% initiator for the radical polymerization and optionally (d) 0.1-2.0 wt.-% additive(s).

Description

EMBODIMENT EXAMPLES

Examples 1-3

Light-Curing Composites Based on a Monomer Mixture According to the Invention

[0056] Corresponding to Table 1 set out below, composites were prepared (all values given in mass-%) based on 44.5% of a silanized SiO.sub.2 mixed oxide with a content of 30 wt.-% ZrO.sub.2 and 20% ytterbium fluoride. In the examples, a monomer mixture according to the invention (20% CMP-1E, 20% GDMA, 20% TMX-UDMA, 25% UDMA and 14.5% D.sub.3MA as well as 0.5% BHT as stabilizer) was used on the one hand and, as a comparison, a monomer mixture based on bis-GMA and TEGDMA (20% bis-GMA, 20% TEGDMA, 20% CMP-1E, 25% UDMA and 14.5% D.sub.3MA as well as 0.5% BHT as stabilizer) was used. The components given in Table 1 were contained as initiator system. The composites were prepared using a kneader (Linden).

[0057] The mechanical properties of the materials were then determined. The bending strength (BS) and the elastic modulus (EM) were measured according to the standard ISO 4049 (DentistryPolymer-based filling, restorative and luting materials). The measured values are given in Table 2.

[0058] To measure the Vickers hardness (VH), metal moulds (h=2 mm, =10 mm) were filled with composite and covered with a PET film. The polymerization was carried out by irradiation from above with a polymerization lamp (LED Bluephase; Ivoclar Vivadent AG; 10 s at 650 mW/cm.sup.2). After preparation, the test pieces were stored in a drying oven at 37 C. for 24 h and then the illuminated upper side of the test pieces was ground flat first with a 2500, then with a 4000 abrasive paper and finally polished with polishing paste. The Vickers hardness was measured on the polymerized upper side with a universal hardness tester (model ZHU0.2; Zwick/Rll). 3 individual measurements were carried out on each test piece. The resulting average values are given in Table 2.

[0059] The results demonstrate that the monomer mixtures according to the invention make it possible to prepare dental materials which have similar properties to materials based on the proven monomers bis-GMA/TEGDMA. Composites which contain a Ge photoinitiator (Ivocerin) in combination with a thiourea derivative have a significantly increased Vickers hardness compared with composites which contain camphorquinone in combination with an amine accelerator (EMBO).

TABLE-US-00001 TABLE 1 Dental composites (values given in wt.-%) Component Ex. 1 Ex. 2 Ex. 3*) Monomer mixture 33.95 35.45 35.45 SiO.sub.2 mixed 44.5 44.5 44.5 oxide.sup.1) YbF.sub.3 20 20 20 Ivocerin.sup.2) 0.05 ATU.sup.3)/Cu.sup.4) 1.50 (65 ppm) CQ.sup.5) 0.02 0.02 EMBO.sup.6) 0.03 0.03 *)Comparison example .sup.1)SiO.sub.2 with a content of 30 wt.-% ZrO.sub.2 .sup.2)Bis(4-methoxybenzoyl)diethylgermanium (photoinitiator, Ivoclar Vivadent) .sup.3)1-Acetylthiourea (accelerator) .sup.4)Cu-acetylacetonate (Cu content in ppm) .sup.5)Camphorquinone (photoinitiator) .sup.6)(4-Dimethylamino) benzoic acid ethyl ester (amine accelerator) .sup.7)Stabilizer

TABLE-US-00002 TABLE 2 Mechanical properties of the composites Bending Elastic Vickers strength modulus hardness Ex. [MPa] [MPa] (MPa) 1 91.0 7.9 4870 197 242.8 10.1 2 98.7 7.9 4910 268 207.7 7.7 3*.sup.) 105 5.5 5120 152 198.4 10.0 *.sup.)Comparison example