Photopolymerizable and dual-curing dental materials based on thiourea derivatives

Abstract

Radically polymerizable dental material which contains as initiator for the radical polymerization a combination of a thiourea derivative and a bisacyldialkylgermanium compound.

Claims

1. A radically polymerizable dental material which comprises as an initiator for the radical polymerization a combination of a thiourea derivative and a bisacyldialkylgermanium compound.

2. The dental material according to claim 1, 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.

3. The dental material according to claim 1, which comprises as the bisacyldialkylgermanium compound, bisbenzoyldiethylgermanium, bisbenzoyldimethylgermanium, bisbenzoyldibutylgermanium, bis(4-methoxybenzoyl)dimethylgermanium, bis(4-methoxybenzoyl)diethylgermanium or a mixture thereof.

4. The dental material according to claim 1, which additionally comprises a hydroperoxide.

5. The dental material according to claim 5, which comprises as the hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, t-butyl peroxide, cumene hydroperoxide, pinane hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, t-amyl hydroperoxide or a mixture thereof.

6. The dental material according to claim 1, which comprises as a polymerizable matrix, radically polymerizable monomers or mixtures of radically polymerizable monomers.

7. The dental material according to claim 6, which comprises a monomer mixture which comprises at least one low-volatile monomethacrylate, at least one highly viscous polyfunctional methacrylate and at least one low-viscosity polyfunctional, methacrylate.

8. The dental material according to claim 7, 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)), and as a low-viscosity dimethacrylate, bismethacryloyloxymethyltricyclo[5.2.1.]decane (TCDMA), glycerol dimethacrylate (GDMA) and/or decanediol-1,10-dimethacrylate (D.sub.3MA) and as low-volatile monomethacrylate p-cumylphenoxyethylene glycol methacrylate (CMP-1E).

9. The dental material according to claim 1, which additionally comprises organic or inorganic particulate filler.

10. The dental material according to claim 9, which comprises filler with a maximum particle size of less than 600 nm.

11. The dental material according to claim 1, which comprises (a) 2.0-20 wt.-% of one or more monomethacrylates, (b) 5.0-60 wt.-% of one or more dimethacrylates, (c) 0-15 wt.-% of one or more acid-group-containing adhesive monomers, (d) 20-90 wt.-% filler(s), (e) 0.01-4.0 wt.-% thiourea derivative(s), (f) 0-3.0 wt.-% hydroperoxide(s), (g) 0.001-1.0 wt.-% bisacyldialkylgermanium compound(s), (h) 0.1-5.0 wt.-% additive(s).

12. The dental material according to claim 11, which comprises (a) 2.0-20 wt.-% of one or more low-volatile monomethacrylates, (b1) 5.0-25 wt.-% of one or more highly viscous dimethacrylates, (b2) 5-30 wt.-% of one or more low-viscosity dimethacrylates, (c) 0-15 wt.-% of one or more acid-group-containing adhesive monomers, (d) 20-90 wt.-% filler(s), (e) 0.01-4.0 wt.-% thiourea derivative(s), (f) 0-3.0 wt.-% hydroperoxide(s), (g) 0.001-1.0 wt.-% bisacyldialkylgermanium compound(s), (h) 0.1-5.0 wt.-% additive(s).

13. The dental material according to claim 1, which comprises 10 to 100 ppm redox catalyst.

14. The dental material according to claim 1, which is free from TEGDMA and bis-GMA.

15. The dental material according to claim 1, which is free from amines.

16. A method of using a dental material according to claim 1 as dental cement, filling composite, veneering material, as materials for preparing inlays, onlays, crowns or bridges comprising preparing the ingredients according to claim 11 and applying the ingredients as a dental cement, filling composite, veneering material.

17. The dental material according to claim 6, wherein the radically polymerizable monomers comprise one or more methacrylates.

18. The dental material according to claim 17, wherein the methacrylates comprise a mixture of mono- and polyfunctional methacrylates.

19. The dental material according to claim 18, wherein the mixture of mono- and polyfunctional methacrylates comprises a mixture of mono- and difunctional methacrylates.

20. The dental material according to claim 7, wherein the at least one highly viscous polyfunctional methacrylate comprises a difunctional methacrylate and wherein the at least one low-viscosity polyfunctional methacrylate comprises a difunctional methacrylate.

21. The dental material according to claim 1, which comprises (a) 5-15 wt.-% of one or more monomethacrylates, (b) 10-40 wt.-% of one or more dimethacrylates, (c) 0-10 wt.-% of one or more acid-group-containing adhesive monomers, (d) 40-80 wt.-% filler(s), (e) 0.1-2.0 wt.-% thiourea derivative(s), (f) 0.1-2.0 wt.-% hydroperoxide(s), (g) 0.005-0.5 wt.-% bisacyldialkylgermanium compound(s), (h) 0.1-2.0 wt.-% additive(s).

22. The dental material according to claim 21, which comprises (a) 5-15 wt.-% of one or more low-volatile monomethacrylates, (b1) 5-15 wt.-% of one or more highly viscous dimethacrylates, (b2) 10-20 wt.-% of one or more low-viscosity dimethacrylates, (c) 0-10 wt.-% of one or more acid-group-containing adhesive monomers, (d) 40-80 wt.-% filler(s), (e) 0.1-2.0 wt.-% thiourea derivative(s), (f) 0.1-2.0 wt.-% hydroperoxide(s), (g) 0.005-0.5 wt.-% bisacyldialkylgermanium compound(s), (h) 0.1-2.0 wt.-% additive(s).

23. The dental material according to claim 1, which comprises 20 to 80 ppm redox catalyst.

24. The dental material according to claim 1, which comprises 30 to 80 ppm redox catalyst.

Description

EXAMPLES

Examples 1-8

Light-Curing Composites Based on an Initiator Composition According to the Invention

[0074] 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% ZrO.sub.2) , 20% ytterbium fluoride and 35.5% of a methacrylate mixture (20% CMP-1E, 20% GDMA, 20% TMX-UDMA, 25% UDMA and 14.5% D.sub.3MA as well as 0.5% BHT as stabilizer). The components detailed in Table 1 were contained as initiator system. The composites were prepared using a kneader (Linden). To measure the Vickers hardness, 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).

[0075] 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 1.

[0076] The results demonstrate that composites which contain a thiourea derivative in addition to a Ge photoinitiator (Ivocerin) have a significantly increased Vickers hardness compared with composites which contain amine accelerator (EMBO or DABA). This means high abrasion stability and makes it possible to prepare dental restorations with high surface smoothness, high gloss and improved stability in the mouth.

TABLE-US-00001 TABLE 1 Initiator content in the monomer of the composites and Vickers hardness Ivocerin.sup.1) ATU.sup.2)/Cu.sup.3) Amine Vickers hardness Ex. [wt.-%] [wt.-%] [wt.-%] (MPa) 1*.sup.) 0.035 0 0 92.64 4.3 2 0.035 1.50/65 0 129.1 7.7 3*.sup.) 0.050 0 0 206.2 9.7 4 0.050 1.50/65 0 242.8 10.1 4a*.sup.) 0 1.50/65 0 does not polymerize 4b*.sup.) 0 1.50/0 0 does not polymerize 5*.sup.) 0.035 0 0.5/EMBO.sup.4) 94.0 2.1 5a*.sup.) 0.035 0 1.5/EMBO.sup.4) 98 11.5 6*.sup.) 0.035 0 0.5/DABA.sup.5) 100.0 5.8 6a*.sup.) 0.035 0 1.5/DABA.sup.5) 95 0.5 7*.sup.) 0.050 0 0.5/EMBO.sup.4) 210.3 15.5 8*.sup.) 0.050 0 0.5/DABA.sup.5) 196.4 8.4 *.sup.)Comparison example .sup.1)Bis-(4-methoxybenzoyl)diethylgermanium (Ivoclar Vivadent AG) .sup.2)1-Acetylthiourea .sup.3)Cu-acetylacetonate (Cu content in ppm) .sup.4)(4-Dimethylamino)benzoic acid ethyl ester .sup.5)N,N-diethyl-3,5-di-tert-butylaniline