WO2004050042A1

WO2004050042A1 - Dental restoration material

Info

Publication number: WO2004050042A1
Application number: PCT/EP2003/012589
Authority: WO
Inventors: Peter Dziuron
Original assignee: Merz Pharma Gmbh & Co. Kgaa
Priority date: 2002-12-04
Filing date: 2003-11-11
Publication date: 2004-06-17
Also published as: EP1572096A1; AU2003279378A1; DE10256690A1

Abstract

The invention relates to a kit for producing a dental restoration material that contains: a) a primer, containing: aa) phosphoric aid and/or phosphoric ester and/or diphosphates; ab) an electron donor, which is active in an acid medium and which is selected from the group consisting of sulfinic acid and the salts thereof; b) polymerizable material containing: ba) polymerizable unsaturated monomers and/or oligomers and/or prepolymers; bb) curing agents, and; bc) fillers. The invention is characterized in that at least one filler is a compound that releases Zn<2+> ions and/or Mg<2+> ions. The invention additionally relates to a dental restoration material that can be produced from this kit. The invention enables a fixing of a multitude of dental materials (metals, ceramics, plastics) to teeth in a manner that is effective whereby being able to be subjected to stress.

Description

Dental restoration material

The invention relates to a kit for producing a dental restoration material for restoring teeth and dentures and for fastening dental material, and a restoration material that can be produced from the kit.

When restoring teeth, a so-called dental material is often attached to a tooth surface or in a tooth cavity. This dental material can in particular be metallic, ceramic or plastic materials, for example inlays, crowns, fillings or the like. It is important to establish a good bond between the tooth and the dental material (filling or inlay), since marginal gap formation can occur if there is insufficient adhesion. Bacteria can penetrate into the marginal gap and cause secondary caries and / or damage the pulp.

Inlays, crowns or other prefabricated fillings are usually attached to the tooth surface or in the tooth cavity using a dental restoration material or cement. This cement must in turn bond well with the material of the tooth.

A primer is known from EP-A-1 121 924 with which tooth surfaces can be prepared for connection to a dental composite material.

The invention has for its object to a kit and a dental restoration material of the type mentioned create, which enables good adhesion values when attaching different dental materials to teeth.

The invention thus relates to a kit for producing a dental restoration material which contains:

a) a primer containing:

aa) phosphoric acid and / or phosphoric acid esters and / or diphosphates,

ab) an electron donor active in an acidic environment selected from the group consisting of sulfinic acid and its salts,

b) polymerizable material containing:

ba) polymerizable, unsaturated monomers and / or oligomers and / or prepolymers,

bb) hardening agents,

bc) fillers,

characterized in that at least one filler is a compound releasing Zn2 ⁺ and / or Mg ²⁺ ions.

The invention further relates to the use of this kit for producing a dental restoration material for restoring teeth and / or dentures and / or for fastening dental material.

Another object of the invention is a dental restoration material that can be obtained from a kit according to the invention.

First, some terms used in the context of the invention are explained. A dental restoration material in the sense of the invention is a cement, polymerizable material or the like (in particular a dental cement) with the aid of which so-called dental materials can be attached to teeth. These dental materials to be attached can be, for example, composites (for example Arabes®, VOCO, Cuxhaven; Tetri-Ceram®, for Vivadent, Liechtenstein), and gold-containing alloys (for example, Degulor M and Stabilor G, for Degussa, Hanau), palladium alloys or non-precious metal alloys (e.g. Wironiu, BEGO, Bremen) as well as ceramic materials such as zirconium oxide or e.g. Empress 1 (3M Espe, Seefeld).

Essential components of the kit according to the invention are a primer and a polymerizable material. The primer used as part of the kit according to the invention can be a one-component system or preferably a multi-component system and is already known per se from EP-A-1 121 924. The primer used according to the invention is preferably free of amine.

"Amine-free" means that the amines usually used together with a peroxide as polymerization initiators are not present in the agent according to the invention, or at most in a very small proportion (preferably less than 0.5% by weight) caused by any impurities. The term "amine-free" does not exclude that amines are contained in the bonds or composite materials which may be used in addition to the agent according to the invention or are added as separate polymerization initiators when the primer according to the invention is processed together with such bonds or composite materials.

When using the kit according to the invention, the corresponding tooth surface or tooth cavity is first prepared with the primer for connection to the second main component of the kit, the polymerizable material. In the context of the invention, the term preparation of tooth surface or cavity encompasses both the etching and the priming of the tooth surface, as is known from EP-A-1 121 924. Priming involves establishing a good connection between the primer and the tooth surface, for example by penetrating the phosphoric acid ends arranged on the spacer sections of the molecules into the dentin tubules of the tooth substance. The primer ensures good mechanical adhesion to the tooth or denture surface. According to the invention, the steps of etching and priming can be carried out in one step.

The essential components of the primer used according to the invention are briefly explained below.

The primer contains phosphoric acid and / or phosphoric acid esters and / or diphosphates. The term phosphoric acid ester encompasses both mono-, di- and triesters of phosphoric acid and its salts. According to the invention, hydroxypropyl methacrylate (HPMA) is preferably used as the alcohol component of the esters, so the phosphoric acid esters are preferably HPMA esters. Other suitable alcohol groups are particularly preferably water-soluble vinyl compounds with a hydroxyl group. According to the invention, however, it is preferred if the agent contains no hydroxyethyl methacrylate (HEMA) or HEMA ester. According to the invention, it is therefore possible to dispense with the use of this substance which has a high risk of allergy.

An electron donor which is effective in an acidic environment is to be understood as any substance which, at pH values below 7, preferably also in the acidic range (pH 3 and less), can react with a polymerization initiator of an autopolymerizing material in such a way that the first , to

Formation of radicals necessary reaction step on the peroxide takes place. In order to carry out this radical formation, an electron transfer to the peroxide oxygen must take place. The Electron donor used according to the invention ensures that this first step can also function in the strongly acidic environment created by phosphoric acid. The sulfinate content of the primer is preferably between 1 and 10% by weight, more preferably 2 and 5% by weight, particularly preferably about 3% by weight. This content is calculated as sodium sulfonate.

The primer component of the kit according to the invention is commercially available from Merz Dental GmbH, Lütjenburg, under the name Resulcin® AquaPrime.

The second essential component of the kit according to the invention is a polymerizable material. It contains polymerizable, unsaturated monomers and / or oligomers and / or prepolymers, preferably compounds containing acrylic, methacrylic, vinyl and / or styryl groups. Suitable polymerisable compounds are familiar to the person skilled in the art and are used in the prior art for the production of composites or compomers. Examples include bis-GMA, UDMA, TEDMA, polymerizable acids such as MSA or the like.

The curing agent is preferably a polymerization catalyst or system, particularly preferably a peroxide such as, for example, benzoyl peroxide.

Fillers in the sense of the invention can be organic or preferably inorganic fillers, for example quartz, (pyrogenic) silicic acid, aluminum oxides, glasses such as barium glasses, aluminum fluorosilicate glasses or the like. Suitable fillers are known to the person skilled in the art.

According to the invention, the fillers or the filler contain a compound releasing Zn ²⁺ or Mg ²⁺ ions. Ion-releasing means that the fillers or filler constituents release Zn2 ⁺ and / or Mg ²⁺ ions under the conditions of the use of the kit in an aqueous environment or in the oral cavity. In the kit according to the invention, the dental restoration material can harden by two different reaction mechanisms. The primary curing takes place through the rapid free radical polymerization of the polymerizable compounds. Secondary curing takes place in the polymer matrix through a cement reaction between the zinc or magnesium ions on the one hand and excess phosphate groups of the primer on the other. This cement reaction has two benefits. On the one hand, it improves the mechanical properties of the dental restoration material and thus also the connection between the tooth on the one hand and the dental material fastened by means of the restoration material according to the invention on the other hand. On the other hand, an excess of phosphoric acid from the primer is reacted by this cement reaction and thus neutralized.

Surprisingly, the dental restoration material according to the invention produced from the kit according to the invention is equally suitable for fastening dental materials of all kinds (metals, ceramics, plastics) to teeth.

The proportion of the compounds releasing zinc and / or magnesium ions in the total amount of the polymerizable material is preferably 2 to 15% by weight, more preferably 6 to 10% by weight (calculated in each case as ZnO or MgO).

The phosphoric acid esters and / or diphosphates of the primer of the kit according to the invention particularly preferably contain at least partially polymerizable double bonds. The primer particularly preferably contains:

a) 1-5% by weight phosphoric acid; b) 10-90% by weight of phosphoric acid monoesters and / or diesters of the formula 0

'I

OR ₂ where R] _ is the same

0 CH ₃

-R _{3 is} -0-CC = CH ₂ ;

R ₂ is H or

0 CH ₃

II I _R ₃ _0-CC = CH ₂ ;

R _{3 is} selected from the group consisting of alkylene groups, alkyleneoxy groups with one or more alkyleneoxy units, alkylene or alkyleneoxy groups substituted with one or more hydroxy groups;

c) 1 - 15 wt .-% phosphoric triesters of the formula

0 = P (OR!) ₃ (II)

with the meaning given above for R] _;

d) 3 to 50% by weight of diphosphates of the formula

0 0

RiO-P 11-O-P II-OR! (III) | |

OR ₂ OR ₂ with the meanings given above for R] _ and R ₂ , where R ₂ in formula (III) may be the same or different.

The primer also contains a mixture of phosphoric acid, a major proportion of phosphoric acid mono- and / or diesters

Phosphoric acid triesters and diphosphates. The low proportion of phosphoric acid is used for the preliminary etching of the tooth surface. The phosphoric acid esters used according to the invention are molecules whose acidic hydroxyl groups can chemically combine with the calcium on the tooth surface. The partially esterified phosphoric acid group is connected to a methacrylate group via an alkylene or alkyleneoxy group (which may carry hydroxyl groups) which serves as a spacer. The methacrylate groups can partially polymerize and thus form a film on the tooth surface into which the dental material can polymerize. Due to their good mobility, the phosphoric acid ends of the molecules can penetrate dentinal tubules and thus improve the mechanical adhesion to the tooth surface.

The percentages in claim 2 relate to the so-called resin content of the primer, which is 100% for a solvent-free mixture. It decreases according to the amount of water added.

It has been shown that the primer of phosphoric acid, mono-, di- and triesters and diphosphates according to the invention has both good storage stability and a very high adhesive force. This primer can be used for etching and priming in a single process step.

The spacer group in the phosphoric acid derivatives is preferably selected from the group consisting of alkylene groups with 2-4 C atoms, ethyleneoxy or propyleneoxy groups, which can consist of up to 4 glycol units (ethylene or propylene glycol units), and alkylene groups with 2-4 C atoms which are substituted with one or two hydroxyl groups. Preferred spacers are ethylene or propylene groups, and also a group of the formula

OH

-CH ₂ -CH-CH ₂ -

or an isomer thereof.

The main part of the primer preferably consists of phosphoric acid mono- and diesters, it is preferably 30-90% by weight, more preferably 40-80% by weight, based on the resin content. A ratio of 20-50% by weight of phosphoric acid monoester and 25-45% by weight of phosphoric acid diester is further preferred. The phosphoric acid content of the primer is preferably 1-3% by weight.

The water content in the ready-to-use primer used is preferably 20-95% by weight, more preferably 20-50% by weight, particularly preferably 25-30% by weight. Low water contents of at most 50, preferably at most 40, more preferably at most 30,% by weight are preferred, which considerably simplifies application in the mouth area due to the higher viscosity of the primer at a lower water content.

The invention further relates to the use of a kit described above for producing a dental restorative material for filling, sealing, restoring teeth and dentures, and in particular for preparing teeth for the attachment of a dental material.

Another object of the invention is a dental restoration material that can be obtained from a kit according to the invention. In a first step, the tooth surface is treated with the primer according to the invention, in a second step the polymerizable material is applied. introduced. Dental materials to be fastened, such as, for example, inlays, crowns or the like, can then be inserted or put on.

The kit according to the invention is at least a two-component system with the components primer and polymerizable material. As a rule, however, these two components in turn consist of two or more components themselves; preferred constellations can be found in subclaims 17 to 21. The kit is particularly preferably a four-component system in which primers on the one hand and polymerizable material on the other hand each consist of two components. In this context, the term component denotes the components or elements of the kit to be handled by the user (dentist) and is not to be confused with the chemical components or ingredients of the kit.

The primer of the kit according to the invention is preferably a two-component system in which one component contains phosphoric acid and / or phosphoric acid esters and / or diphosphates and the other component in aqueous solution is a salt of a sulfinic acid. Compared to free sulfinic acid, sulfinates have the advantage of being stable in aqueous solution, but in the case of the salts the free electron pair of the sulfur is more strongly bound to this atom and is therefore only available to a limited extent for the initialization of the peroxide (hardening agent). A primer is produced from this two-component system shortly before use. The phosphoric acid milieu of the first component then forms free sulfinic acid, which is an effective electron donor. The disadvantage of free sulfinic acid, namely its easy oxidizability or disproportionation, is negligible when this free acid is released shortly before use.

The tooth surface is primed with this primer. The polymerizable material is then applied, which in turn is preferably mixed from two components. One component can, for example, the polymerizable Compounds and fillers contain, the other component of the curing agent. A certain amount of mixing of the primer and the polymerizable material then takes place directly on the tooth surface, which then leads to the fact that, after polymerizing, the described additional cement reaction can take place with the participation of excess phosphoric acid of the primer and zinc or magnesium ions.

The invention is explained below on the basis of exemplary embodiments and comparative examples.

example 1

Production of a kit according to the invention

The various components of a kit were made as follows:

Primer component A; 29 g of HPMA (hydroxypropyl methacrylate) are taken up in 50 ml of chloroform. The solution is under

Stir in 15 g portions of phosphorus pentoxide. After 24 hours, the mixture is filtered, 50 ml of water are added and the mixture is stirred for a further 24 hours. The chloroform phase is then separated off and concentrated in vacuo. Yield 32 g. The reaction mixture is analyzed by ³¹ P-NMR spectroscopy. It has the following composition: 1% phosphoric acid, 39.5% phosphoric acid monoester, 29.1% phosphoric acid diester, 0.5% phosphoric acid triester, 28.5% diphosphate. All percentages are percentages by weight.

Primer component B: is a 3% aqueous sodium sulfinate solution.

The polymerizable material contains the following polymerizable monomers: Bis-GMA (isopropylidene-bis [2 (3) -hydroxy-

3 (2) - (4-phenoxy) propyl methacrylate) 13.7 g

TEDMA (3,6-dioxaoctamethylene dimethacrylate 13.3 g barium alumoborosilicate glass 48.0 g

ZnO 6.0 g

Benzyl peroxide (hardening agent) 1.0 g

An amine such as, for example, N, N-dimethyl-p-toluidine, whose free electron pair on

A nitrogen interacts with the peroxide and can thus initiate the radical formation reaction. According to the invention, this is not absolutely necessary, since sulfinic acid as an electron donor can also initiate autopolymerization.

The components of the polymerizable material mentioned are homogenized before use.

Example 2

Two metallic (Wironium and Degulor M) test stamps with a diameter of 6 mm and a height of 8 mm were manufactured, the flat, fat-free and dry composite surfaces with corundum (120 μm) were blasted at a pressure of about 2.2 bar.

Example 3

The crowns were extracted from extracted human teeth, the exposed dentin surfaces were ground on wet grinding wheels (corundum, 600 grit) and checked for enamel freedom by light microscopy. With these surfaces fixed on a glass plate, the teeth were embedded in Technovit (from Kulzer, Wehrheim) and, after devestment, ground again briefly and checked by light microscopy to ensure that the dentin surfaces are free of embedding plastic and lie in one plane with it. The 1: 1 mixed primer was then Components A and B were rubbed on the ground dentin surfaces over a period of 30 s and then dried until the layer on the dentin surface no longer moved noticeably in the air flow. A self-adhesive plastic film with a circular opening with a diameter of 5.5 mm (hole reinforcement rings classic, Stuttgart) was glued to each of the primed dentin surfaces to prevent the adhesive material from creeping up on the test stamp during the further process. The mixed polymerizable material from example 1 was then applied on the one hand as a thin film to the composite surfaces of the respective test stamps from example 2 and on the other hand a sufficient proportion (as a small drop) with the circular opening of the plastic film on the primed dentine surface of the exposed primer with scrubbing movements with a short-haired, solid brush for 5 s. The test stamp with its pretreated composite surface was then placed concentrically on the pretreated exposed area of the dentin surface under light pressure. Three minutes later, the samples were stored in water at 37 ° C for 24 hours. After storage, the residues lying on the plastic film and the film were removed and the shear bond strength measurements were carried out at a truss feed of 1 mm min ^"1 on the T22K material testing machine from JJ Lloyds, Gerungen. An average value of 17. Measured at 9 MPa, no metal-specific influence (Wironium, Degulor M) was observed.

Comparative Examples 1 to 3

In the comparative examples, the formulation of example 1 was modified as follows:

Comparative Example 1

Omission of the zinc oxide in the polymerizable material Comparative Example 2

Omission of sodium sulfinate in primer component B

Comparative Example 3

Omitting the zinc oxide in the polymerizable material and omitting the sodium sulfinate in primer component B.

With the formulations modified in this way, test specimens were produced in accordance with the methods described in Examples 2 and 3 and the shear bond strengths were determined.

Comparative Example 1: 13.4 Mpa Comparative Example 2: not measurable Comparative Example 3: 2 MPa

Claims

claims

1. Kit for producing a dental restoration material, which contains:

a) a primer containing:

aa) phosphoric acid and / or phosphoric acid esters and / or diphosphates,

b) polymerizable material containing:

bb) hardening agents,

bc) fillers,

characterized in that at least one filler is a compound releasing Zn ²⁺ and / or Mg ²⁺ ions.

2. Kit according to claim 1, characterized in that the primer contains:

i) 1-5% by weight phosphoric acid;

ii) 10-90% by weight of phosphoric acid mono- and / or diesters of the formula O HO-P-OR! (I)

in which

R] _ the same

is;

R ₂ is H or

is;

iii) 1-15% by weight of phosphoric triesters of the formula

0 = P (OR!) ₃ (II)

with the meanings given above for R_;

iv) 3 - 50 wt .-% diphosphates of the formula

OR ₂ OR ₂

with the meanings given above for R] _ and R ₂ , where R ₂ in formula (III) may be the same or different.

3. Kit according to claim 2, characterized in that R _{3 is} selected from the group consisting of alkylene groups with 2-4 C atoms, ethyleneoxy or propylene oxy groups from up to 4 glycol units, alkylene groups with 2-4 C Atoms that are substituted with one or two hydroxy groups.

4. Kit according to claim 3, characterized in that R _{3 is} an ethylene or propylene group.

5. Kit according to claim 3, characterized in that R _{3 is the} same

OH

-CH ₂ -CH-CH ₂ -

or is an isomer of it,

6. Kit according to one of claims 2 to 5, characterized in that the proportion of phosphoric acid mono- and / or diesters in the primer 30 - 90 wt .-%, preferably 40 - Is 80% by weight.

7. Kit according to claim 6, characterized in that the primer contains 20 - 50 wt .-% phosphoric acid monoester and 25 - 45 wt .-% phosphoric diester.

8. Kit according to one of claims 2 to 7, characterized in that the primer contains 1-3% by weight of phosphoric acid.

9. Kit according to one of claims 1 to 8, characterized in that the primer is in aqueous solution.

10. Kit according to claim 9, characterized in that the proportion of the solvent water in the primer 20-95

% By weight, preferably 20-50% by weight, more preferably 25-30% by weight.

11. Kit according to one of claims 1 to 10, characterized in that the polymerizable unsaturated monomers and / or oligomers and / or prepolymers contain acrylic, methacrylic, vinyl and / or styryl groups or a mixture of these groups.

12. Kit according to claim 11, characterized in that the polymerizable unsaturated monomers and / or oligomers and / or prepolymers contain acrylic and / or methacrylic groups.

13. Kit according to one of claims 1 to 12, characterized in that the curing agent is a polymerization catalyst or system.

14. Kit according to claim 13, characterized in that the polymerisation catalyst contains peroxide.

15. Kit according to one of claims 1 to 14, characterized in that at least one of the fillers ZnO and / or MgO.

16. Kit according to one of claims 1 to 14, characterized in that the proportion of the compound releasing Zn ²⁺ and / or Mg ²⁺ ions in the polymerizable material, calculated as ZnO or MgO, 2-15% by weight , preferably 6-10% by weight.

17. Kit according to one of claims 1 to 16, characterized in that the ingredients aa) and ab) are combined to form a component.

18. Kit according to one of claims 1 to 17, characterized in that the ingredients ba) and bb) are combined to form a component.

19. Kit according to one of claims 1 to 17, characterized in that the ingredients ba) and bc) are combined into one component.

20. Kit according to one of claims 1 to 17, characterized in that the ingredients bb) and bc) are combined into one component.

21. Kit according to one of claims 1 to 17, characterized in that the ingredients ba), bb) and bc) are combined into one component.

22. Use of a kit according to one of claims 1 to 21 for the production of a dental restoration material for

Restoring teeth and / or dentures and / or for attaching dental material.

23. Dental restoration material, obtainable from a kit according to one of claims 1 to 21.