DE112007000877B4 - Method for marking a medical instrument and medical instrument with a marking - Google Patents

Abstract

Method for marking a medical instrument, in particular a surgical or dental instrument made of ceramic or metal, in particular a dental drill, comprising- applying a layer, which forms an outer partial surface of the instrument, of a mixture of polymerizable acrylates or methacrylates or of a solid partially polymerized mixture of polymerizable acrylates or methacrylates on the instrument,- initiating the polymerisation of the mixture- curing the mixture on the instrument, wherein- the layer forming an outer partial surface of the instrument itself has a color and/or is translucent in such a way that it can be penetrated by an underlying colored layer has a colored effect, - the acrylates or methacrylates are monomers with at least two acrylate or methacrylate groups, preferably di- or trifunctional methacrylates, - the monomers are selected from the group formed by BIS-GMA and TEDMA and mixtures of these compounds, and- the mixture further comprises a preferably non-crystalline filler, characterized in that the mixture contains 70 to 90% by weight BIS-GMA, 10 to 30% by weight TEDMA and 0 to 3% by weight crystal-free fumed silica such comprises that the sum of the components of the mixture is 100% by weight.

Description

FIELD OF THE INVENTION

The invention relates to a method for marking a medical instrument, in particular a surgical and dental instrument such as a dental drill, and an instrument, in particular a surgical or dental instrument that is marked according to the method.

BACKGROUND OF THE INVENTION

Dental drills differ, e.g. in the design of the rotary head, depending on its intended use, such as drilling holes of varying fineness, milling or polishing. Color markings are also desired for other surgical instruments, for example to distinguish the age of the instruments, the material or the manufacturer.

Various methods for marking medical instruments are known. For example, the international patent application WO 2005/102204 A2 In order to be able to identify different dental burs more quickly and easily, we suggest marking the dental burs with a colored Teflon ring.

From the EP 0 864 266 B1 a method of decorating metal ornaments using a composition containing methacrylate is known.

From the GB 1 241 823 A curable compositions are known.

From the DE 10 2004 027 299 A1 a dental instrument with a marking element is known.

The EP 0 836 845 A2 discloses a dental light-curing opaquer.

In practice, however, the known markings have not proven to be satisfactory in every respect. They are sometimes very expensive, difficult to process, e.g. to grind, and fade or flake off during disinfection processes such as autoclaving.

Surgical instruments made of ceramic or metal are items that are used several times on different patients under conditions that are as germ-free as possible. For thorough and careful cleaning and sterilization, they must therefore withstand autoclave treatment, especially at high temperatures and pressures, which are typically over 120°C and over 2 bar. Furthermore, the surgical instruments should be as biocompatible and non-toxic as possible.

Another problem, especially with dental instruments, is in the DE 20 2004 002 472 U1 addressed: the accidental or intentional multiple use of single-use instruments. In fact, a number of instruments are expressly designed for single use only and, in particular, are not intended to be sterilized in an autoclave after use. The DE 20 2004 002 472 U1 therefore proposes applying a thermochromic color with an irreversible color change to disposable dental drills, with the color change being triggered, for example, by the heat in the autoclave, so that improperly sterilized instruments can be easily recognized and discarded. However, it is missing in the DE 20 2004 002 472 U1 at a concrete executable marker.

OBJECT AND SUMMARY OF THE INVENTION

The invention is based on the object of facilitating the marking of surgical instruments made of ceramic or metal, in particular dental burs, and of providing or enabling easily manufacturable, durable and biocompatible medical, in particular surgical and dental instruments such as dental burs with color markings, disposable instruments with reliable marking with to provide an irreversible color change.

For this purpose, the invention proposes a method for marking a medical instrument, in particular a surgical or dental instrument made of ceramic or metal, in particular a dental drill.

The use of the mixture of polymerized acrylates or methacrylates makes it possible to make a marking that survives without damage even the most severe conditions, such as those prevailing during autoclave treatment. Such labels are also biocompatible and non-toxic. The markings can be used on ceramic, metal, synthetic, organic or mineral surfaces.

Suitable mixtures and their application to metal and ceramic surfaces are in the patent application DE 197 09 280 A1 shown, the entire content of which is referred to for disclosure of the invention.

• - EG Nr. 216-367-7, CAS-Nr. 1565-94-2, BIS-GMA, Bisphenol-A-Glycidylmethacrylat, (1-Methylethyliden)bis(4,1-Phenylenoxy(2-3,1-Propandiyl))bis-Methacrylat, bzw. 2-Methyl-2-Propensäure-(1-Methylethyliden)bis(4,1-Phenylenoxy(2-Hydroxy-3,1-Propandiyl))Ester oder
• - (1-Methylethyliden)bis[4,4-Phenylenoxy(2-Hydroxy-3,1-Propandiyl)]bis-Methacrylat oder
• - EG Nr. 203-652-6, CAS-Nr. 109-16-0, TEDMA, 2,2'-Ethylendioxidiethyldimethacrylat, bzw. Triethylenglycoldimethacrylat bekannt. Als besonders vorteilhafte Methacrylate für das erfindungsgemäß verwendete Polymerisationsgemisch dienen auch
• - Urethandimethacrylat, das auch durch die CAS-Nr. 72869-86-4 bezeichnet wird, und
• - Tetraethylenglycoldimethacrylat, das auch durch die CAS-Nr. 109-17-1 bezeichnet wird,

aus deren Gemisch ein Polymer gebildet und erfindungsgemäß verwendet wird.Methacrylates which are particularly advantageous for the polymerization mixture used according to the invention are given under the designations

• - EC No. 216-367-7, CAS no. 1565-94-2, BIS-GMA, bisphenol A glycidyl methacrylate, (1-methylethylidene)bis(4,1-phenyleneoxy(2-3,1-propanediyl))bis-methacrylate, or 2-methyl-2- Propenoic acid (1-methylethylidene)bis(4,1-phenyleneoxy(2-hydroxy-3,1-propanediyl)) ester or
• - (1-methylethylidene)bis[4,4-phenyleneoxy(2-hydroxy-3,1-propanediyl)]bis-methacrylate or
• - EC No. 203-652-6, CAS no. 109-16-0, TEDMA, 2,2'-ethylene dioxide diethyl dimethacrylate, or triethylene glycol dimethacrylate. Methacrylates which are particularly advantageous for the polymerization mixture used according to the invention also serve
• - Urethane dimethacrylate, also known by the CAS no. 72869-86-4, and
• - Tetraethylene glycol dimethacrylate, also known by the CAS no. 109-17-1,

from the mixture of which a polymer is formed and used according to the invention.

Further advantageous acrylates and methacrylates are defined in the dependent claims.

The mixture can advantageously include a preferably non-crystalline filler such as quartz sand, crystal-free highly disperse silicon dioxide, aluminum oxide, ceramic, glass, silanized glass powder, glass ceramic or mixtures of these fillers.

A particularly preferred filler is the one with CAS no. 112945-52-5 designated crystal-free highly disperse silicon dioxide or pyrogenic silicic acid.

Another particularly preferred filler is the one with CAS no. 100402-78-6 referred to 0.7 µm fine barium glass with disperse silica. The filler is usually inorganic.

A particularly preferred mixture comprises 70 to 90% by weight, preferably 79% by weight BIS-GMA, 10 to 30% by weight, preferably 20% by weight TEDMA and 0 to 3% by weight, preferably 1% by weight % of crystal-free, highly disperse silicon dioxide such that the sum of the components of the mixture is 100% by weight.

The mixture is polymerized, for example, with a photoinitiator which, when irradiated with blue light, specifically with a wavelength of 400 to 500 nm, starts the polymerization, in particular of acrylates and/or methacrylates.

The photoinitiator can be benzophenone, benzoin, an alpha-diketone, acylphosphine oxide, camphorquinone, one or more of their derivatives, and mixtures thereof.

A mixture polymerized by pressure and/or temperature can also be used according to the invention. It is therefore possible to use mixtures which are polymerized without a photoinitiator. In this way it can be safely ruled out that no residual photoinitiator or its reaction products are present in the mixtures used. Combinations of pressure and temperature values are then selected for the polymerization in such a way that a cured mixture is obtained. For this purpose, the pressure is preferably above 1 bar, in particular above 2 bar, preferably between 2.5 and 5 bar. The temperature is preferably above 100°C, preferably between 110 and 150°C.

Steam pressure can also be used to obtain the desired pressure and temperature conditions. In particular, the desired pressure and temperature conditions can be obtained in a conventional autoclave such as is used for sterilizing surgical or dental elements. As a result, curing and sterilization of an instrument can advantageously be carried out in one step. Sterile, possibly sterile-packaged instruments are thus easily available.

Colored markings obtained by curing a solid partially polymerized mixture of polymerizable acrylates or methacrylates are preferably used. Such a solid partially polymerized mixture has a non-liquid soft consistency at room temperature and atmospheric pressure, in particular a consistency like butter, dough or gel.

Such a solid, partially polymerized mixture, mixed with pigments and optionally fillers to form a mass, can be applied to at least one depression or groove of an instrument to be marked for color marking in such a way that this groove is covered by the mass. Advantageously, the instrument is immersed in glycerin for curing under pressure and temperature in such a way that the mass is completely immersed. A pressure and temperature range is then selected in such a way that the mass hardens. The hardened polymer can then be ground down in such a way that the color mark produced in the area of the indentation is flush with the surface of the instrument.

Instead of glycerin, other suitable liquids or gels can also be used such as polyethylene glycol solutions, paraffins, mineral oils, silicone oils, etc. Liquids or liquid mixtures are preferably used which, when polymers are cured under pressure and temperature, have a favorable effect on the gap-free filling of the depression by the polymer. This avoids areas on the marked instruments where contamination or sources of infection can accumulate. A smooth, easy-to-clean surface of the instrument is obtained in the area of the groove, particularly after the hardened polymer has been ground down. Liquids such as glycerin or gels can function to allow curing to take place in a protected reaction environment. In a steam sterilization autoclave, for example, curing under glycerin can take place largely without the presence of water.

In particular, a solid partially polymerized mixture with a buttery consistency is preferably formed from a copolymer of the dimethacrylate monomers urethane dimethacrylate, CAS no. 72869-86-4, and tetraethylene glycol dimethacrylate, CAS no. 109-17-1 and, if applicable, the above with the CAS no. 100402-78-6 described filler. The partially polymerized mixture can be obtained from the monomers by photopolymerization and/or polymerization under pressure and/or temperature. The pigment can be added before or after the solid partially polymerized mixture is prepared. The composition of the mixture is preferably selected in such a way that a density of the fully cured mixture of between 1.5 and 2.1 g/cm ³ , preferably 1.6 and 1.7 g/cm ³ , is obtained.

Pigments are used, for example, in the colors white, e.g. in the form of titanium dioxide, or in the colors yellow, orange, light red, dark red, light green, dark green, light blue, dark blue, black, transparent, UV red or UV blue.

Examples of pigments are known under the designations CAS no. 38185-91-4 (jet black), CAS no. 910010-29-1 (pink), CAS no. 13463-67-7 (white), CAS no. 910010-35-5 (yellow), CAS no. 910010-15-7 (kiwi or deep yellow), CAS no. 57455-37-5 (deep blue), CAS no. 990001-08-8 (neon red), CAS no. 99001-09-9 (neon blue and neon green), CAS no. 99001-15-7, CAS no. 99001-02-9 (orange), CAS no. 99001-10-0 (red, deep red), CAS no. 99001-06-7 (neon yellow), which are available from Heraeus Kulzer GmbH, Werheim, Germany, among others.

Organic or inorganic pigments can be used.

To mark disposable instruments, the layer of a mixture of polymerizable acrylates or methacrylates or a solid, partially polymerized mixture of polymerizable acrylates or methacrylates that forms part of the outer surface of the instrument serves as a protective layer for an underlying colored layer of a thermochromic color with an irreversible color change.

The protective layer ensures that the thermochromic ink does not get onto a patient and cannot detach from the instrument. A film as a protective layer enables disposable dental drills with a thermochromic color to be produced at low cost, but cannot always reliably fulfill the protective function and may tear or be damaged.

The manufacture of a sterile instrument can advantageously be simplified in that UV radiation is used both to harden the protective layer and to sterilize the instrument. The work steps of curing and sterilizing are thereby standardized. UV radiation can also be applied to a prefabricated instrument in UV-transmissive packaging to ensure sterility.

Advantageously, the thermochromic ink is introduced into a recess of the instrument and then, if necessary, the polymerization mixture is also introduced into this recess.

Grinding off part of the hardened polymerization mixture that protrudes from the recess allows a smooth, flush surface of the instrument to be produced in the area of the protective layer. This prevents sources of infection from sticking or getting stuck after unpacking the sterile instrument.

The thermochromic color can also be printed directly onto the instrument.

The thermochromic paint is advantageously applied in the form of a symbol or inscription. As a result, after a color change, for example, a stop symbol or z. For example, the word "NO" becomes visible to ensure that disposable items that have been sterilized in the autoclave are sorted out, even without thorough training of the staff.

A partially polymerized viscous polymerization mixture is advantageously used for ease of processing.

The polymerization mixture comprises acrylates and/or methacrylates and optionally pigments. From this acrylate polymers are available that are particularly biocompatible and with body or mucous membranes of a patient may come into contact. Pigments, especially in a color that corresponds to the thermochromic color before the color changes under the influence of heat, ensure that an inscription only becomes visible after the color has changed. The polymerization mixture can thus be suitably adapted to different thermochromic colors.

EXAMPLES

EXAMPLE 1

• 79 Gew.-% BIS-GMA,
• 20 Gew.-% TEDMA
• 1 Gew.-% kristallfreies hochdisperses Siliziumdioxid der Marke ACEMATT® TS 100/20 von Degussa.

The following mixture 1 is prepared:

• 79% by weight BIS-GMA,
• 20% by weight TEDMA
• 1% by weight of ACEMATT® TS 100/20 brand crystal-free highly disperse silicon dioxide from Degussa.

• 98 Gew.-% des obigen Gemischs 1
• 2 Gew.-% Ultramarinblau L6498

The following mixture 2 is produced:

• 98% by weight of mixture 1 above
• 2% by weight Ultramarine Blue L6498

0.03% by weight of UV stabilizer (Tinuvin P, Ciba Geigy) and 0.25% by weight of camphorquinone are added to mixture 2.

The mixture is kept in the refrigerator at about 8° C. for three days in the dark.

The titanium metal surface of a dental bur is cleaned with acetone and air dried for 2 minutes.

The saved mixture is then applied with a brush to a ring portion of the titanium metal surface of a dental bur.

It is irradiated for 60 seconds with a hand-held light device with a wavelength in the range of 400 and 600 nm and then cured for 20 minutes.

The color application remains stable even after several passes in the autoclave.

EXAMPLE 2

• - Urethandimethacrylat, CAS-Nr. 72869-86-4,
• - Tetraethylenglycoldimethacrylat, CAS-Nr. 109-17-1,
• - 0,7 µm feines Barium-Glas mit disperser Kieselsäure, CAS-Nr. 100402-78-6

wurde unter der Marke Novorit® von der Firma Heimerle + Meule GmbH, 75179 Pforzheim, Deutschland bezogen.Mixture 3 of:

• - Urethane dimethacrylate, CAS no. 72869-86-4,
• - Tetraethylene glycol dimethacrylate, CAS no. 109-17-1,
• - 0.7 µm fine barium glass with disperse silica, CAS no. 100402-78-6

was purchased under the Novorit® brand from Heimerle + Meule GmbH, 75179 Pforzheim, Germany.

• 98 Gew.-% des obigen Gemischs 3
• 2 Gew.-% Ultramarinblau L6498.

The following mixture 4 is prepared by kneading with a spatula:

• 98% by weight of the above mixture 3
• 2% by weight Ultramarine Blue L6498.

A titanium metal plate with a groove is cleaned with acetone and air dried for 2 minutes.

The mixture is then applied to the furrow with a spatula and covered with aqueous 98% glycerin.

The titanium metal plate with the mixture 4 covered with glycerol is placed in the autoclave for 3 hours at 120° C. and 3 bar steam pressure in order to fully harden the mixture.

In this example, the composition of the mixture is selected in such a way that a density of 1.63 g/cm ³ is obtained.

EXAMPLE 3

A blind hole with a depth of 5 mm and a diameter of 5 mm is drilled in a titanium metal plate and cleaned with acetone.

The hole is partially filled with tert-butoxycarbonylated 9-aminoperylene-3,4-dicarboximide.

• 79 Gew.-% BIS-GMA,
• 20 Gew.-% TEDMA
• 1 Gew.-% kristallfreies hochdisperses Siliziumdioxid der Marke ACEMATT® TS 100/20 von Degussa.

The following polymerization mixture is produced:

• 79% by weight BIS-GMA,
• 20% by weight TEDMA
• 1% by weight of ACEMATT® TS 100/20 brand crystal-free highly disperse silicon dioxide from Degussa.

0.03% by weight of UV stabilizer (Tinuvin P, Ciba Geigy) and 0.25% by weight of camphorquinone are added to this mixture 2.

The hole is filled with the polymerization mixture.

It is irradiated for 30 seconds with a wavelength of 470 nm and then cured for 20 minutes and irradiated again for 30 minutes.

Claims (18)

Method for marking a medical instrument, in particular a surgical or dental instrument made of ceramic or metal, in particular a dental drill, comprising - applying a layer, which forms an outer partial surface of the instrument, of a mixture of polymerizable acrylates or methacrylates or of a solid partially polymerized mixture of polymerizable acrylates or methacrylates on the instrument, - initiating the polymerisation of the mixture - curing the mixture on the instrument, whereby - the layer forming an outer partial surface of the instrument itself has a color and/or is translucent in such a way that it can be penetrated by an underlying one colored layer has a colored effect, - the acrylates or methacrylates are monomers with at least two acrylate or methacrylate groups, preferably di- or trifunctional methacrylates, - the monomers are selected from the group formed by BIS-GMA and TEDMA and mixtures of these compounds, and - the mixture further comprises a preferably non-crystalline filler, characterized in that the mixture contains 70 to 90% by weight BIS-GMA, 10 to 30% by weight TEDMA and 0 to 3% by weight crystal-free fumed silica such comprises that the sum of the components of the mixture is 100% by weight. procedure after claim 1 , wherein the layer that forms an outer partial surface of the instrument is translucent in such a way that it appears colored by an underlying colored layer, characterized in that the underlying colored layer consists of a thermochromic color with an irreversible color change. procedure after claim 1 or 2 , characterized in that the layer forming an outer partial surface of the instrument and a possibly underlying colored layer is or are introduced into a depression, in particular a circumferential groove, in the instrument. procedure after claim 3 , characterized in that the layer forming an outer partial surface of the instrument is introduced into the depression in such a way that it protrudes from the depression and is partially ground off after the polymerization mixture has hardened. procedure after claim 2 , characterized in that the thermochromic ink is printed on the instrument. procedure after claim 2 , characterized in that the thermochromic paint is applied in the form of a symbol or an inscription. Procedure according to one of Claims 1 until 6 , characterized in that the mixture when applied to the instrument comprises a photoinitiator, which is preferably selected from the group formed by benzophenone, benzoin an alpha-diketone, acylphosphine oxide, camphorquinone and derivatives thereof and mixtures of these photoinitiators. procedure after claim 7 , characterized in that the polymerization is initiated by applying an activation wavelength of 400 to 500 nm, preferably 470 nm, to the mixture. procedure after claim 1 , characterized in that the polymerization mixture is cured with UV radiation. Procedure according to one of Claims 1 until 9 , characterized in that the polymerization of the mixture is started and/or the mixture is cured by applying pressure and/or temperature. procedure after claim 10 , characterized in that the mixture is cured in an autoclave. procedure after claim 10 or 11 , characterized in that the mixture is cured under glycerin. Procedure according to one of Claims 1 until 12 , characterized in that the monomers are selected from the group formed by tetraethylene glycol dimethacrylate, diethylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate forming monomers, butanediol dimethacrylate, hexanediol dimethacrylate, decanediol dimethacrylate, dodecanediol dimethacrylate, bisphenol A dimethacrylate, trimethylolpropane trimethacrylate, tetraethylene glycol diacrylate, diethylene glycol diacrylate, ethylene glycol diacrylate, polyethylene glycol diacrylate forming monomers, butanediol diacrylate, hexanediol diacrylate, decanediol diacrylate, dodecanediol diacrylate, bisphenol A diacrylate, trimethylolpropane triacrylate, their derivatives and mixtures of these compounds. procedure after Claim 13 , characterized in that the monomers comprise urethane dimethacrylate and/or tetraethylene glycol dimethacrylate. Procedure according to one of Claims 1 until 14 , characterized in that the filler is selected from quartz sand, crystal-free highly disperse silicon dioxide, aluminum oxide, ceramic, glass, silanized glass powder, glass ceramic, barium glass and mixtures of these fillers. Procedure according to one of Claims 1 until 15 , characterized in that the mixture comprises 79% by weight BIS-GMA, 20% by weight TEDMA and 1% by weight crystal-free fumed silica such that the sum of the components of the mixture is 100% by weight. Medical instrument, in particular surgical or dental instrument made of ceramic or metal, with a marking, characterized in that the instrument according to a method according to one of Claims 1 until 16 is marked. Medical instrument after Claim 17 , characterized in that the instrument is a dental drill.