Orthodontic bracket

Abstract

The invention relates to an orthodontic bracket. It is provided that the bracket has at least one antibacterially effective surface, wherein the antibacterially effective surface is a structured surface (42) or a surface (43) chemically modified by the binding of a pharmaceutically active ingredient.

Description

The invention relates to an orthodontic bracket and a method for producing such a bracket.In firmly seated orthodontic therapy, so-called brackets (German: platelets) are used, which are bonded to teeth of a patient. A bracket typically includes a plate, also referred to as a pad, and a base body, also referred to as a bracket body. The bracket is connected to the tooth via the plate, while the base body has a slot, which is also referred to as an arch guide groove or slot, through which an orthodontic wire, which is also referred to as an arch or archwire, is guided. The glued-on brackets are connected to one another by means of the wire. To retain the wire in the slot of the bracket, the bracket may include a closure flap, also referred to as a clip. The brackets and the wire together form an orthodontic bracket. Exemplary brackets are described in EP 1 977 717 A1 and WO 2013 / 025489 A1.The brackets may contain all necessary information regarding the three-dimensional tooth position of each tooth in the dental arch. They are therefore also referred to as "preprogrammed brackets". For this purpose, the brackets have a design in which this information is integrated. They can therefore accommodate a straight arc, which enables their use in the "straight wire" technique (german "straight arc" technique).Brackets are typically made of metal, typically stainless steel (also referred to as "stainless steel"). However, they can also consist of other materials, such as glass fiber-reinforced plastics or ceramic. Brackets are also known which have a combination of ceramic and metal. For example, the bracket may include a pad and a base body made of ceramic, while the clip and / or the slot are made of metal to minimize the frictional forces between the wire and the bracket. The metal may be stainless steel.Metal brackets are characterized by good mechanical properties, removability, low manufacturing costs, and ease of mass production, but are less aesthetic and exhibit plaque retention.Plastic brackets, although aesthetic and cost effective to manufacture, are rarely used due to swellability, poor mechanical properties (slot deformation and torque loss), and high plaque adhesion.A great advantage of ceramic brackets is, in addition to the unrestricted aesthetic nature, the comparatively low plaque adhesion. In contrast, there is more difficult removability after therapy, which may lead to melt injuries, and high friction values. In addition, ceramic brackets should not be used in the lower jaw because of the risk of melt abrasion by occlusal contacts 2. Ceramic is one of the hardest materials in nature second to diamond 3. In a simulated oral environment with ceramic brackets in contact with the antagonistic teeth, after only 100 chewing cycles (1 chewing cycle / sec; light chewing force ~900 g) corresponding to the load and time occurring during a single regular meal, a wear rate of 253 μm and a melt volume loss of 0.3 mm 2 could be detected 4, The like could also be confirmed in another study 2. Although this is known, ceramic brackets are still used in daily practice in both jaws.In order to move a tooth three-dimensionally through the bone, different archwires are also used in combination with the above-mentioned brackets. The materials used include β-titanium, nickel-titanium alloys, cobalt chromium tungsten silicon alloys, also available under the trade name "Remanium", or steel wires. Depending on the treatment phase and mechanics, more or less elastic sheets are varied.During a tight orthodontic treatment, due to the materials used and limited accessibility to the tooth surface, despite daily oral hygiene 5,6 an increased accumulation of plaque around the brackets can occur 7. Plaque consists of a biofilm of a multispecies of microorganisms growing as an ecosystem on hard and soft tissues in the oral cavity 8 and is the primary cause of caries, gingivitis and periodontitis 9-11. An increased accumulation of plaque increases the risk of mineralizations (caries risk) 7 and the formation of so-called white spot lesions (WSL) 12 in the bracket circumferency 13-14( FIG. 1 ), which are observed in these patients with a prevalence of 2 to 97% 15,16. Their prevention is the goal of each orthodontist by controlling cariogenic biofilm 17. Efficient mechanical elimination of the organized biofilm and reduction of its formation is still prior to the corner pillars of plaque control 6,18, but other specific anti-biofilm strategies 6,8 for preventing plaque accumulation and WSL are also being recommended urgent in orthodontic patients.Sealer, fillers and coatings of brackets and arches can reduce the rate of plaque accumulation, exert an antibacterial effect 19,21, and are therefore a good treatment option in patients with increased caries risk 21,22.Various bonding systems and bracket environment fasteners have been developed which also exhibit good antibacterial effects in vitro, but have only a low fluoride release capacity and thus only minimal to no caries-preventive effects 23,24. Their clinical effectiveness for preventing WSL is therefore generally classified as low 25,26. In addition, composite surfaces are known to have low surface energy and are very susceptible to biofilm development 27, so that reducing plaque formation around the brackets in poorly accessible areas with a toothbrush appears more effective.Therefore, it is also desirable to produce a bracket surface having antimicrobial properties in order to prevent or at least reduce biofilm formation and at the same time prevent the risk of caries. Furthermore, this is intended to meet the mechanical and thermal load scenarios in the oral environment, for which reason a metallic material, even on account of the above-mentioned advantages, represents the material which is most frequently used and is most suitable for this purpose. Thus, brackets should meet several requirements simultaneously, i.e., they should have antibacterial properties, be mechanically and thermally resistant, as well as biocompatible, and ultimately meet aesthetic requirements.Hydrophobic and superhydrophobic coatings of brackets, also referred to as "organosilane coatings", exhibited, for example, minimized surface wettability and bacterial adhesion of the surfaces and thus carried a biofilm reduction at 28. Other surface modifications, such as silver-platinum nanoparticles 29, zinc oxide nanoparticles" (ZnO nanoparticles) and copper oxide nanoparticles 30( CuO nanoparticles), and silver particles 31 show promising antimicrobial properties, for example against Streptococcus mutans or aggregator actinomycetemcomintans in some cases. Nanomercuric and titanium oxide coatings on steel and ceramic brackets exhibit both antimicrobial effects 19,32 and good biocompatibility 33 and can minimize smooth surface caries and WSL in bracket circumference 19. However, in an animal study for silver nanoparticle coated brackets, compared to the control group, higher silver ion levels in saliva and blood 19. occurred after 7 days. Another modification of brackets and arch materials is a coating with rhodium. However, the antimicrobial properties have not been sufficiently studied up to now. Moreover, rhodium is available only to a limited extent, is very expensive, toxic in high ion concentration and there are indications of carcinogenesis.The choice of the surface material of the brackets can therefore have a decisive effect on the biocompatibility 34. However, the longevity of these surface coatings is fragile 31, loss rates of up to 100% are sometimes described 35.There are currently no satisfactory solutions to the above problems. A reduction in germs or protection against demineralisation of the hard tooth substance is achieved above all by applying fasteners to the tooth surface surrounding the bracket. In order to achieve antimicrobial effects, e.g. a rhodium coating of the brackets or the introduction of silver ions or other substances into the base material have been attempted.In summary, it can be stated that the known brackets each have disadvantages. Metal brackets have increased attachment of seeds causing caries to the bracket and around the bracket. Metal brackets have a high potential for creating white spots around the bracket. Although rhodium-coated metal brackets are said to have a seed-reducing effect, the cancerous effect of rhodium ions is opposite to this, there being no data hitherto available for a possible release of rhodium ions from the surface coating. Silver ions with which metal brackets have been doped are detectable to be cancerous and are liberated from various materials, and therefore such metal brackets are practically no longer used.Although ceramic brackets have in principle a smaller accumulation of microorganisms causing caries in comparison with metal brackets, no surface modifications have been known to date. For this reason, white spots are observed in the same way as in metal brackets. Ceramic brackets also have an increased risk of breakage upon removal with potential melt injuries, for example melt tears or internal fractures.A bracket outer seal requires additional conditioning of the melt surface, for example by etching on the melt, which, however, is associated with a loss of hard tooth substance. Bacterial attachment is not prevented with a bracket surrounding area seal. The longevity of the seals is very variable, with partial or complete loss being possible by daily teeth cleaning.The object of the invention is to eliminate the disadvantages of the prior art. In particular, an orthodontic bracket is to be specified which has better antibacterial properties. A method for producing such a bracket is also to be specified.This object is achieved by the features of claims 1 and 14. Practical embodiments of the inventions are evident from the features of the dependent claims.According to the invention, an orthodontic bracket is provided which has at least one antibacterially active surface, wherein the antibacterially active surface is a structured surface or a surface chemically modified by binding a pharmaceutical active substance. Preferably, the structured surface is a hydrophobic or superhydrophobic surface.The bracket according to the invention has better antibacterial properties than the brackets known from the prior art. This is also attributable to the fact that the bracket according to the invention has an antibacterially active surface. In addition, the bracket according to the invention is mechanically and thermally resistant and biocompatible. It also satisfies aesthetic requirements.The invention provides for the modification of the surface properties of a bracket by structuring or chemical modification. This prevents or at least minimizes the adhesion and the multiplication of germs, in particular caries-causing germs. In this way, a caries-protective effect is achieved. In relation to orthodontic treatment, a plaque growth in areas of the brackets of a solid bracket is thus prevented in the long term and so-called white spots are prevented.Structuring alters the surface tension and wettability of the surface of the bracket and makes it difficult to attach bacteria. The roughness is likewise changed by the structuring. The combination of these two effects thus prevents massive plaque accumulation. However, this invention does not represent a substitute for regular oral hygiene.It can be provided that the bracket according to the invention has a plate for connection to a tooth and a base body, wherein the surfaces of the base body are antibacterially active surfaces. The plate is the so-called pad, the base body is the so-called body. It can further be provided that the plate has a surface for connection to the tooth and at least one further surface, wherein the surface for connection to the tooth is not an antibacterially active surface and wherein the further surface is an antibacterially active surface. In this way, it can be ensured that the formation of a microbially effective surface has no influence on the adhering of the bracket according to the invention onto the tooth and its retention on the tooth. In one embodiment of the bracket according to the invention, all surfaces of the bracket, except for the surface of the plate intended for connection to the tooth, are antibacterially active surfaces. The surface of the plate intended for connection to the tooth is also referred to as the bottom side of the pad. Thus, an embodiment of a bracket according to the invention can be provided in which the underside of the pad is not an antibacterially active surface, while all other surfaces of the bracket according to the invention are antibacterially active surfaces. In another embodiment of the bracket according to the invention, its entire surface is an antibacterially active surface.Apart from the antibacterially active surface provided according to the invention, the bracket according to the invention can be a bracket known per se from the prior art. It can correspond, for example, to the bracket described in EP 1 977 717 A1. The antibacterially active surface provided according to the invention is obtained by structuring and / or chemically modifying a base surface of the bracket. The structured surface can be obtained by machining a base surface of the bracket. The chemically modified surface can be obtained by chemically modifying a base surface of the bracket. The term "base surface" refers to a surface of the bracket that has not been subjected to structuring and / or chemical modification.In the following, a bracket according to the invention, the at least one antibacterially active surface of which is a structured surface, is referred to as the first embodiment according to the invention, while a bracket according to the invention, the at least one antibacterially active surface of which is a chemically modified surface, is referred to as the second embodiment according to the invention.First Embodiment of the InventionThe first embodiment of the bracket according to the invention has a structured surface as an antibacterially active surface. The structured surface is not a coating and therefore also does not have the disadvantages of a coating.The structured surface may be a hydrophobic or superhydrophobic surface. A hydrophobic surface is understood to mean a surface in which a water droplet which is in contact with this surface has a contact angle in a range from 90° to less than 140°. A super hydrophobic surface is understood to mean a surface in which a water droplet which is in contact with this surface has a contact angle of 140° or higher. The term "contact angle" is understood to mean the angle that the surface of a water drop forms with the structured surface of the bracket, including the drop volume. Because the surface of the water drop is curved, the angle between a tangent that abuts the water drop and the surface of the bracket is determined. The contact angle can be determined, for example, by the "Sesile Drop Method" and use of the Yong Laplace fit 37,38. The contact angle may be a random contact angle. It can be provided that the contact angle is in a range from 140 to 180°, preferably from 150° to 175°, particularly preferably 150° to 160°, when the structured surface is wetted with water.The structured surface is obtained by structuring the base surface of the bracket. The structured surface is preferably hydrophobic or superhydrophobic.A structured surface can be produced, for example, by machining the base surface of a bracket by means of a laser. The structured surface is preferably a laser-structured surface. Preferably, the structured surface is formed on a metal bracket. A structured surface has the advantage that it has antimicrobial properties and at the same time a coating of the structured surface is not required. Studies have shown that a structured surface has antimicrobial effects on enterogenic germs 36. A structured surface is thus preferably a metallic surface. The bracket according to the invention can thus be a metal bracket whose surface is wholly or partly a structured surface.It can be provided that the structured surface has a surface structure which, starting from the surface of the bracket, has depressions. The surface of the bracket can be its base surface. The depressions are formed in the base surface. The depressions can be groove-shaped depressions. The groove-shaped depressions can form a mesh which extends over the structured surface of the bracket. The depressions can have, starting from the surface of the bracket, a depth in a range from a few nanometers to a few 10 micrometers and / or a width in the range from a few nanometers to a few 10 μm. For example, the indentations may have a depth in a range from 10 nanometers to 80 micrometers and / or a width in the range from 10 nanometers to 80 micrometers from the surface of the bracket.It can be provided that the structured surface has a surface structure. The surface structure may be a periodic structure having a periodicity in a range from 1 to 50 μm.It can be provided that the structured surface has a roughness in a range from 10 nm to 100 μm Sa (surface-related roughness value). The roughness can be determined by means of the methods described in standard DIN EN ISO 25178-6:2010-06, in particular confocal microscopy 39.The term "metal" is understood to mean a material which is a chemical element belonging to the metals or an alloy which contains at least one metal. For example, the metal may be a steel such as stainless steel or nickel-free steel, or a titanium alloy. Stainless steel is also referred to as stainless steel. An example of a stainless steel is a steel containing 0 to 15 wt. nickel, 11.5 to 20 wt. % chromium, 0 to 2 wt. % silicon, 0 to 2 wt. % manganese, 0 to 6.5 wt. % molybdenum, 0 to 0.7 wt. % titanium, 0 to 5 wt. % copper, 0 to 4 wt. % aluminum, 0 to 0.6 wt. % niobium, 0 to 1.2 wt. % carbon, 0 to 0.5 wt. % tantalum, and the balance 100 wt. % iron. Further suitable alloys are described, for example, in the catalog "Forestandent" of Bernhard Förster GmbH, Pforzheim, DE, Info No. 230 / 03.2023, Chapter 13, pages 1.1 to 1.17.Due to its structured surface, the bracket has properties that minimize bacterial accumulation in critical areas that are difficult to access by the toothbrush. The structuring of the base surface of the bracket alters the roughness and surface tension, thereby preventing or at least reducing seed attachment. There is no risk of toxic ions being released after structuring of the base surface. The structured surface has a biofilm-reducing effect, is caries-protective and reduces the risk of white spots. Provision can be made to apply a sealer to the tooth surface around the structured antimicrobial bracket. This can be advantageous in particular if, owing to the modification provided according to the invention, the biofilm bears increasingly on the tooth surface around the bracket instead of on the bracket, i.e. in regions which lie outside the effective laser-structured region around the bracket.The altered roughness and the altered surface tension bring about reduced adhesion of caries-pathogenic germs. In regular oral hygiene, an additional caries-protective effect is thus exerted. The structuring produces a hydrophobic or superhydrophobic surface and thus an antimicrobial potential thereof. It is therefore possible to dispense with coating of the base surface. Studies show that structuring can have effects on different enterogenic microorganisms.Second Embodiment of the InventionThe second embodiment of the bracket according to the invention has a surface which is chemically modified by attachment of a pharmaceutical active substance as an antibacterially active surface. A surface chemically modified by binding a pharmaceutical active substance is a chemically modified surface.The chemically modified surface comprises a pharmaceutically active agent bonded to the base surface of the bracket. For this purpose, it can be provided that the pharmaceutically active substance is bound to the base surface via an anchor unit. The anchor moiety may be a chemical moiety having a first functional group through which the anchor moiety is chemically bonded to the base surface and one or more second functional groups. Via the second functional group(s) the active pharmaceutical ingredient or an enzymatically cleavable linker unit to which the active pharmaceutical ingredient is chemically bound can be chemically bound to the anchor unit.The first functional group can be surface-active groups which form a chemical bond with the surface of the bracket.The second functional group may be a maleic anhydride group or a maleic acid group. The enzymatically cleavable linker moiety can be a peptide sequence. The peptide sequence may be a peptide sequence cleaved by the class of peptidases, for example metalloproteases, cysteine, aspartyl, serine and threonyl proteases.The anchor moiety may be a polymer, for example a copolymer. The anchor moiety can be, for example, an amphiphilic molecule having a hydrophobic portion of styrene, methacrylic or isobutene moieties and a hydrophilic portion of maleic anhydride or maleic acid moieties. Such an anchor unit is described in DE 102015 109 599 B3 in connection with the coating of plastics one-way materials. Reference is made to this description. The pharmaceutical active substance provided according to the invention is a biologically active molecule in the sense of DE 10 2015 109 599 B3.The pharmaceutical active substance can have a direct or indirect antimicrobial effect. The pharmaceutical active ingredient has an immediate effect if it is antibacterially active without cleavage from the anchor moiety. The pharmaceutical active substance has an indirect action if it receives its action only after cleavage of the anchor unit by an enzyme. The enzyme may be a bacterial enzyme, for example a bacterial protease. If the enzymatically cleavable linker moiety is cleaved by an enzyme such as a bacterial protease, the pharmaceutical agent is released. The active ingredient released is antibacterially active and can exert this activity in the environment. The linker moiety may have an enzymatically cleavable bond.The pharmaceutically active ingredient is preferably selected from the group consisting of hexetidine, a hexetidine derivative, chloro-hexidine, a chloro-hexidine derivative and a fluoride. These active ingredients have an antibacterial effect. The fluoride may be an inorganic fluoride compound such as NaF, Na 2 PFO 3 or ZnF, or an organic fluoride compound such as hydrofluorides of amines. Hydrofluorides of amines are also referred to as aminefluorides. Examples of hydrofluorides of amines are N-octadecyltrimethylenediamine-N,N,N-tris(2-ethanol)-dihydrofluoride and 9-octadecenylamine hydrofluoride.The enzymatically cleavable linker moiety is preferably selected from the group consisting of an ether moiety, a peptide moiety and a maleimide moiety. A preferred linker moiety is a peptide moiety or a maleimide moiety. An ether unit is understood to mean a group -O-.The attachment of a pharmaceutical active substance to the base surface is preferably effected to a plastic surface. The bracket according to the invention can thus be a plastic bracket or a bracket which has a metal core sheathed with plastic. The plastic can be a plastic as used in the prior art for producing brackets. The plastic can be, for example, a polyamide or a polyetheretherketone (PEEK). An example of a commercially available polyamide is Trogamide ® CX. The plastic can be a glass fiber-reinforced plastic.Due to the binding of a pharmaceutical active substance, the bracket is provided with properties that minimize bacterial accumulation in critical areas that are difficult to access by the toothbrush. In particular, the initial bacterial accumulation is minimized. If the pharmaceutical active substance has an indirect antibacterial effect, the antibacterial surface provided according to the invention enables the release of the pharmaceutical active substance, which then achieves an antimicrobial effect. The anchor unit remains on the surface of the bracket and, depending on the cleavage site of the enzyme, optionally a part of the linker unit remains. In this way, the concentration of the pharmaceutical active ingredient is increased in the immediate environment of the bracket, so that the pharmaceutical active ingredient also develops its antibacterial effect in the areas around the bracket, i.e. in the areas in which white spots normally arise. Thus, the bracket circumferency is better protected.It can be provided that the enzymatically cleaved pharmaceutical active ingredient is replaced. For this purpose, a chemical compound which has the pharmaceutical active ingredient and a unit bonded thereto and which can bond to the anchor unit remaining on the surface or to the residue of the linker unit can be guided from the outside, for example via a mouthrinse solution, to the chemically modified surface and bond there to the anchor unit or to the part of the linker unit remaining on the anchor unit. The unit bound to the pharmaceutical active substance and the part of the linker unit remaining on the anchor unit can thereby form a new linker unit. In this way, the chemically modified surface can be regenerated. With regard to the renewed attachment of the pharmaceutical active substance to the surface, this process can also be referred to as "redoping". If the pharmaceutical active ingredient is hexetidine, which is bonded to the anchor unit via an enzymatically cleavable linker unit, then after its cleavage from the outside, for example via a hexetidine-containing mouthrinse solution, the hexetidine can be passed again to the chemically modified surface and bond there. This bond can then be cleaved again under the influence of a bacterial enzyme.Further details for carrying out the chemical modification of surfaces are described, for example, in connection with the coating of plastics one-way materials in DE 10 2015 109 599 B3. Reference is made to this description.According to the invention, a method for producing an orthodontic bracket is also provided, which has at least one antibacterially active surface, wherein the antibacterially active surface is a structured surface or a surface chemically modified by binding a pharmaceutical active substance. The method according to the invention comprises the formation of an antibacterially active surface by altering a base surface of the bracket.The method according to the invention is suitable in particular for producing the bracket according to the invention. Details of the method according to the invention have already been described in connection with the bracket according to the invention. Reference is made to the description thereof. A first method used for producing the first embodiment of the bracket according to the invention and a second method used for producing the second embodiment of the bracket according to the invention are described below.First MethodThe first method enables the formation of a structured surface. This surface is obtained by changing a base surface of the bracket. For this purpose, it can be provided that the method according to the invention comprises structuring the base surface of the bracket with a laser. In this way, an antibacterially effective surface can be produced.The laser can be, for example, an ultra-short pulse laser or short pulse laser. The laser may be a laser having a frequency of a few Hz to a few GHz. The laser preferably has an average power of 10 milliwatts to 10kW. It can have pulse energies of 1 μJ to a few 10 mJ. Pulse lengths in a range from 100 fs to 30 ps are preferably used. The laser is focused, for example, with an optical system to a focus diameter of 1 μm to 10 cm on the material surface. The laser beam is moved laterally relative to the surface by either moving the material to be processed (for example a metallic bracket) under the laser beam or moving the laser beam over the material to be processed by means of optics. A combination of both strategies can also be carried out. A further possibility is represented by various methods which can write the structure to be produced directly into the material by means of lasers, for example "direct laser interference patterning" 38. The surface to be patterned may be scanned once or many hundreds to tens of thousands of times with the laser beam to produce a patterned and biofilm-repellent surface. The laser beam can be moved over the surface line by line with line spacings of 5 μm to 5 cm and / or at speeds of 1 mm / s to 10,000 mm / s via a changing hatching pattern in order to fill the region to be structured. A changing hatch pattern can be obtained via angle changes in multiple passes.Second MethodThe second method enables the formation of a surface chemically modified with a pharmaceutical active substance. This surface is obtained by changing a base surface of the bracket. For this purpose, it can be provided that the base surface of the bracket is modified by binding a pharmaceutical active substance. In this way, an antibacterially effective surface can be produced.For this purpose, it can be provided that an anchor unit is initially chemically bonded to the base surface. The attachment of the anchor moiety to the base surface may be via its first functional group. Subsequently, in the embodiment, the active pharmaceutical ingredient can be chemically bound to the anchor unit. The binding of the pharmaceutical active substance to the anchor unit can take place via the second functional group. In another embodiment, the pharmaceutically active agent is bound to the anchor moiety via a linker moiety. Alternatively, an anchor moiety to which the active pharmaceutical agent is already bound directly or via the linker moiety may be bound to the base surface. The attachment of the anchor moiety to the base surface may be via its first functional group.The invention is explained in more detail below on the basis of exemplary embodiments, which are not intended to restrict the invention, with reference to the drawings. Figure shows FIG. 1 is a photograph of teeth showing massive mineralizations and enamel caries after insufficient oral hygiene during fixed orthodontic therapy. Healthy enamel in the region of the previous bracket position is surrounded by so-called white spots; FIG. 2 is a schematic top view of the surface of a steel plate having a region formed as a superhydrophobic, structured surface and a region corresponding to the base surface; FIG. 3 shows scanning electron micrographs of steel surfaces which each have a region having a superhydrophobic, structured surface and a region having a base surface (FIG. 3A : region having a superhydrophobic, irregularly structured surface; FIG. 3B : region having a superhydrophobic, regularly structured surface); FIG. 4 shows representations of the surfaces shown in FIG. 3 after 6 h of incubation and colonization with S. mutans; FIG. 5 shows schematic representations of a base surface of a bracket (FIG. 5A : top view; FIG. 5B : side view); FIG. 6 shows schematic representations of a superhydrophobic, structured surface of a bracket, which was obtained by changing the base surface shown in FIG. 5 (FIG. 6A : top view; FIG. 6B : side view); and FIG. 7 shows schematic representations of a surface of a bracket chemically modified with a pharmaceutical active substance, which surface has been obtained by changing the base surface shown in FIG. 5 (FIG. 7A : plan view; FIG. 7B : side view of a first embodiment; FIG. 7C : side view of a second embodiment).The section of a surface of a steel plate shown in FIG. 2, which can be used, for example, for the production of metal brackets, has a first region 11 and a second region 21. A structuring 12 is formed on the first region 11, whereby a superhydrophobic, structured surface 42 is obtained. The second region 21 is the base surface 41 of the steel plate. The base surface of this region 21 has not been subjected to any change, in particular no structuring. It can be seen in FIG. 2 that significantly less biofilm 31 is attached to the surface in the first region 11 than in the second region 21.FIGS. 3 a) and 3 b) each show a scanning electron microscope representation (SEM, 500 magnification each) of steel surfaces. Each of the two steel surfaces has a first region 11 and a second region 21. The first region 11 and the second region 21 are separated from each other by a boundary region indicated by an arrow. The first region 11 has a structuring, the second region 21 has no structuring, but is the unstructured base surface. The first region 11 of the surface shown in FIG. 3 a) has an irregular structuring, the first region 11 of the surface shown in FIG. 3 b) has a regular structuring in the form of parallel, groove-shaped depressions. The structured regions 11 thus have different surface properties.The representations shown in FIGS. 4 a) and 4 b) show the steel surfaces shown in FIGS. 3 a) and 3 b) after 6 h of incubation and colonization with the bacterium S. mutans. What is shown is a life-dead fluorescence staining. Live bacteria fluoresce in green. A clearly different degree of biofilm deposition can be seen depending on the structuring. Only a slight biofilm deposition has taken place in the first region 11, wherein no biofilm is formed locally in the first region 11 of the metal surface shown in FIG. 4 a).FIGS. 5A and 5B show schematic representations of a base surface 41 of a bracket. This base surface is altered to form an antimicrobial surface on the bracket. For this purpose, a structuring 12 is applied to the base surface 41, whereby the base surface 41 is converted into a superhydrophobic, structured and biofilm-binding surface 42 (FIGS. 6A and 6B ).FIGS. 7A, 7B and 7C show a surface 43 chemically modified with a pharmaceutical active agent W. In the embodiment shown in FIG. 7B, the pharmaceutical active agent W is bonded to an anchor unit A, which in turn is bonded to the base surface 41 of a bracket. In the embodiment shown in FIG. 7C, the pharmaceutical active ingredient W is bound to an enzymatically cleavable linker unit L. The linker unit L is bonded to an anchor unit A, which in turn is bonded to the base surface 41 of a bracket.List of reference characters11 first region 12 structuring 21 second region 31 biofilm 41 base surface 42 structured surface 43 chemically modified with a pharmaceutical active substanceLiterature: Literature1. 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A., The effect of hexetidine mouthwash on the prevention of plaque and gingival inflammation: a systematic review. Int J Dent Hyg 2011, 9 (3), 182-90.9. Takahashi, N.; Nyvad, B., The role of bacteria in the caries process: ecological perspectives. Journal of Dental Research 2011, 90 (3), 294-303.10. Pitts, N.B.; Zero, D.T.; Marsh, P.D.; Ekstrand, K.; Weintraub, J.A.; Ramos-Gomez, F.; Tagami, J.; Thetman, S.; Tsakos, G.; Ismail, A., Dental caries. Nat Rev Dis Primers 2017, 3, 17030.11. Loe, H.; Theilade, E.; Jensen, S.B., Experimental Gingivitis in Man. Journal of periodontology 1965, 36, 177-87.12. Hochli, D.; Hersberger-Zurfluh, M.; Papageorgiou, S. N.; Eliades, T., Interventions for orthodontically induced white spot lesions: a systematic review and meta-analysis. Eur J Orthod 2017, 39(2), 122-133.13. Srivastava, K.; Tikku, T.; Khanna, R.; Sachan, K., Risk factors and management of white spot lesions in orthodontics. J Orthod Sci 2013, 2 (2), 43-9.14. Gorelick, L.; Geiger, A. M.; Gwinnett, A. J., Incidence of white spot formation after bonding and banding. American journal of orthodontics 1982, 81 (2), 93-8.15. Al Maaitah, E.F.; Adeyemi, A.A.; Higham, S.M.; Pender, N.; Harrison, J.E., Factors affecting demineralized during orthodontic treatment: a post-hoc analysis of RCT rec. American journal of orthodontics and dietary orthopedics: official publication of the American Association of Orthodontics, its constituent societies, and the American Board of Orthodontics 2011, 139 (2), 181-91.16. Huang, G. J.; Roloff-Chiang, B.; Mills, B. E.; Shalchi, S.; Spiekerman, C.; Korpak, A. M.; Starrett, J. L.; Greenlee, G. M.; Urgesholt, R. J.; Matunas, J. C., Efficacy of MI Paste Plus and ProvideDent fluoride variation for treatment of white spot lesions: a randomized controlled trial. American journal of orthodontics and dietary orthopedics: official publication of the American Association of Orthodontics, its constituent societies, and the American Board of Orthodontics 2013, 143 (1), 31-41.17. Pithon, M.M.; Sant'Anna, L.I.; Baiao, F.C.; dos Santos, R.L.; Coqueiro Rda, S.; Maya, L.C., Assessment of the efficacy of maruhwass in reducing cariogenic biofilm in orthodontic patients: a systematic review. Journal of dermatotry 2015, 43 (3), 297-308.18. Sharma, N.C.; Gallustians, H.J.; Qaqish, J.; Charles, C.H.; Vincent, J.W.; McGuire, J.A., Antiplaque and antigingivalitis efficacy of a hexetidine mouthwash. Journal of clinical periodontology 2003, 30 (7), 590-4.19. Metin-Gursoy, G.; Taner, L.; Akca, G., Nanosilver coated orthodontic brackets: in vivo antibacterial properties and ion release. European Journal of orthodontics 2017, 39 (1), 9-16.20. Metin-Gursoy, G.; Taner, L.; Akca, G., Nanosilver coated orthodontic brackets: in vivo antibacterial properties and ion release. Eur J Orthod 2017, 39(1), 9-16.21. Arash, V.; Keikhaee, F.; Rabiee, S. M.; Rajabnia, R.; Khafri, S.; Taveanafar, S., Evaluation of Antibacterial Effects of Silver-Coated Stainless Steel Orthodontic Brackets. J Dent (Tehran) 2016, 13 (1), 49-54.22. Arash, V.; Keikhaee, F.; Rabiee, S. M.; Rajabnia, R.; Khafri, S.; Taveanafar, S., Evaluation of Antibacterial Effects of Silver-Coated Stainless Steel Orthodontic Brackets. J Dent (Tehran) 2016, 13 (1), 49-54.23. Coordinates, S. L.; Jost-Brinkmann, P. G.; Prager, T. M.; Bartzela, T.; Visel, D.; Jacker, T.; Muller-Hartwich, R., A comparison of different sealeds preventing demineralized around brackets. Journal of orofacial orthopedics= Fortschritt of orthodontics: Organ / official journal Deutsche Gesellschaft fur Orthodontics 2018, 79 (1), 49-56.24. Derks, A.; Katsaros, C.; Frencken, J. E.; van't Hof, M. A.; Kuijpers-Jagtman, A. M., Caries-inhibiting effect of preventive measures during orthodontic treatment with fixed appliances. A systematic review. Cares Res 2004, 38 (5), 413-20.25. Bechtold, T. E.; Sobiegalla, A.; Markovic, M.; Berneburg, M.; Goz, G. R., In vivo efficacy of enamel sealed sealed orthodontic brackets. Journal of orofacial orthopedics= Fortschritt of the orthodontics: Organ / official Journal Deutsche Gesellschaft fur Orthodontics 2013, 74 (6), 447-57.26. Kamber, R.; Meyer-Luckel, H.; Kloukos, D.; Tennert, C.; Virichs, R.J., Efficacy of sealeds and bonding materials during fixed orthodontic treatment to prevent enamel demineralized: a systematic review and meta-analysis. Sci Rep 2021, 11 (1), 16556.27. Hannig, C.; Hannig, M., The oral cavity-a key system to inferior substrate-dependent bioadhesion on solid surfaces in man. Clinical oral investigation 2009, 13 (2), 123-39.28. Oliveira, A. S.; Kaizer, M. R.; Azevedo, M. S.; Oglari, F. A.; Cenci, M. S.; Moraes, R. R., (Super)hydrophobic coating of orthodontic dental devices and reduction of early oral biofilm retention. Biomedical materials 2015, 10(6), 06004.29. Ryu, H. S.; Bae, I. H.; Lee, K. G.; Hwang, H. S.; Lee, K. H.; Koh, J. T.; Cho, J. H., Antibacterial effect of silver-platinum coating for orthodontic appliances. The angle orthodontist 2012, 82 (1), 151-7.30. Ramazanceadeh, B.; Jahanbin, A.; Yaghoubi, M.; Shahthmassbi, N.; Ghazvini, K.; Shakeri, M.; Shafaee, H., Comparison of Antibacterial Effects of ZnO and CuO Nanoparticles Coated Brackets against Streptococcus Mutans. J Dent (Shiraz) 2015, 16 (3), 200-5.31. Chambers, C.; Stewart, S.; Su, B.; Sandy, J.; Ireland, A., Prevention and treatment of demineralized during fixed application therapy: a review of current methods and future applications. British Dental Journal 2013, 215 (10), 505-11.32. Cao, S.; Wang, V.; Cao, L.; Wang, V.; Lin, B.; Lan, W.; Cao, B., Preparation and antimicrobial assay of ceramic brackets coated with TiO2thin films. Korean J Orthod 2016, 46 (3), 146-54.33. Zhang, R.; Zhang, W.; Bai, X.; Song, X.; Wang, C.; Gao, X.; Tian, X.; Liu, F., Report: Disclosure on the development of nano Ag / TiO2coating bracket and its antibacterial property and biocompatibility in orthodontic treatment. Pak J Pharm Sci 2015, 28 (2 Suppl), 807-10.34. Rongo, R.; Valletta, R.; Bucci, R.; Rivieccio, V.; Galeotti, A.; Michellotti, A.; D'Anto, V., In vitrobiocompatibility of nickel-titanium ethetic orthodontic archwires. The angle orthodontist 2016, 86 (5), 789-95.35. da Silva, D.L.; Mattos, C.T.; Simao, R.A.; de Oliveira Ruellas, A.C., Coating stability and surface characteristics of ethotic orthodontic coated archives. The angle orthodontist 2013, 83 (6), 994-1001.36. Epperlein, N.; Menzel, F.; Schlibert, K.; Kater, R.; Bonse, J.; Sameh, J.; Kruger, J.; Toepel, J., Influence of femtoscond laser produced nanostructures on biofilm growth on steel. Appl Surf Sci 2017, 418, 420-424.37. Groenendijk, Max. "Fabrication of Super Hydrophobic Surfaces by fs Laser Pulses: How to Produce Self-Cleaning Surfaces." Laser Technology Journal 5.3 (2008): 44-47.38. Peter, A., Lutey, A.H., Faas, S., Romoli, L., Onuseit, V., & Graf, T. (2020). Direct laser interference patterning of stainless steel by ultrashort pulses for antibacterial surfaces. Optics & Laser Technology, 123, 105954.39. DIN EN ISO 25178-6:2010-06, industry standardReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedEP 1 977 717 A1 [0002, 0026]WO 2013 / 025489 A1

[0002] DE 102015 109 599 B3 [0042, 0049]Cited Non-Patent LiteratureDIN EN ISO 25178-6:2010-06 [0034, 0061]Forestandent" from Bernhard Förster GmbH, Pforzheim, DE, Info No. 230 / 03.2023, Chapter 13, pages 1.1 to 1.17

[0035] Karamouzos, A.; Athanasiou, A.E.; Papadopoulos, M.A., Clinical characteristics and properties of ceramic brackets: A comprehensive review. American journal of orthodontics and dietary orthopedics: official publication of the American Association of Orthodontics, its constituent societies, and the American Board of Orthodontics 1997, 112 (1), 34-40

[0061] Newesely, H.; Rossiwall, B., [Enamel abrasion and enamel gears by porcelain brackets]. Inf Orthod Orthodontist 1989, 21 (4), 577-94

[0061] Billai, A.R.; Gaitdharan, A.; Kumar, S.; Shah, A., Comparison of the fractional resistance between archwire and different bracket system: An in vitro study. J Pharm Bioalled Sci 2014, 6 (Suppl 1), pp 150-5.

[0061] Viazis, A. D.; DeLong, R.; Bevis, R. R.; Rudney, J. D.; Pintado, M. R., Enamel abrasion from ceramic orthodontic brackets under an artificial oral environment. American journal of orthodontics and dietary orthopedics: official publication of the American Association of Orthodontics, its constituent societies, and the American Board of Orthodontics 1990, 98 (2), 103-9

[0061] Tang, X.; Sensat, M.L.; Stoltenberg, J.L., The antimicrobial effect of chlorhexidine variant on mutans streptococci in patients with fixed orthodontic appliances: a systematic review of clinical efficiency. Int J Dent Hyg 2016, 14 (1), 53-61

[0061] Takenaka, S.; Ohsumi, T.; Noiri, V., Evidence-based strategy for dental biofilms: Current evidence of maruhwass on dental biofilm and gingivitis. Jpn Dent Sci Rev 2019, 55 (1), 33-40

[0061] Okada, E.M.; Rieuro, L.N.; Stuani, M.B.; Borsatto, M.C.; Fidalgo, T.K.; Paula-Silva, F.W.; Kuchler, E.C., Effects of chlorhexidine variation on caries during orthodontic treatment: a systematic review and meta-analysis. Brazilan oral research 2016, 30 (1), e115

[0061] Afennich, F.; Slot, D. E.; Hossainian, N.; Van der Weijden, G. A., The effect of hexetidine mouthwash on the prevention of plaque and gingival inflammation: a systematic review. Int J Dent Hyg 2011, 9 (3), 182-90

[0061] Takahashi, N.; Nyvad, B., The role of bacteria in the caries process: ecological perspectives. Journal of Dental Research 2011, 90 (3), 294-303

[0061] Pitts, N.B.; Zero, D.T.; Marsh, P.D.; Ekstrand, K.; Weintraub, J.A.; Ramos-Gomez, F.; Tagami, J.; Thetman, S.; Tsakos, G.; Ismail, A., Dental caries. Nat Rev Dis Primers 2017, 3, 17030

[0061] Loe, H.; Theilade, E.; Jensen, S.B., Experimental Gingivitis in Man. Journal of periodontology 1965, 36, 177-87

[0061] Hochli, D.; Hersberger-Zurfluh, M.; Papageorgiou, S. N.; Eliades, T., Interventions for orthodontically induced white spot lesions: a systematic review and meta-analysis. Eur J Orthod 2017, 39(2), 122-133

[0061] Srivastava, K.; Tikku, T.; Khanna, R.; Sachan, K., Risk factors and management of white spot lesions in orthodontics. J Orthod Sci 2013, 2 (2), 43-9.

[0061] Gorelick, L.; Geiger, A. M.; Gwinnett, A. J., Incidence of white spot formation after bonding and banding. American journal of orthodontics 1982, 81 (2), 93-8

[0061] Al Maaitah, E.F.; Adeyemi, A.A.; Higham, S.M.; Pender, N.; Harrison, J.E., Factors affecting demineralized during orthodontic treatment: a post-hoc analysis of RCT rec. American journal of orthodontics and dietary orthopedics: official publication of the American Association of Orthodontics, its constituent societies, and the American Board of Orthodontics 2011, 139 (2), 181-91

[0061] Huang, G. J.; Roloff-Chiang, B.; Mills, B. E.; Shalchi, S.; Spiekerman, C.; Korpak, A. M.; Starrett, J. L.; Greenlee, G. M.; Urgesholt, R. J.; Matunas, J. C., Efficacy of MI Paste Plus and ProvideDent fluoride variation for treatment of white spot lesions: a randomized controlled trial. American journal of orthodontics and dietary orthopedics: official publication of the American Association of Orthodontics, its constituent societies, and the American Board of Orthodontics 2013, 143 (1), 31-41

[0061] Pithon, M.M.; Sant'Anna, L.I.; Baiao, F.C.; dos Santos, R.L.; Coqueiro Rda, S.; Maya, L.C., Assessment of the efficacy of maruhwass in reducing cariogenic biofilm in orthodontic patients: a systematic review. Journal of dermatotry 2015, 43 (3), 297-308

[0061] Sharma, N.C.; Gallustians, H.J.; Qaqish, J.; Charles, C.H.; Vincent, J.W.; McGuire, J.A., Antiplaque and antigingivalitis efficacy of a hexetidine mouthwash. Journal of clinical periodontology 2003, 30 (7), 590-4

[0061] Metin-Gursoy, G.; Taner, L.; Akca, G., Nanosilver coated orthodontic brackets: in vivo antibacterial properties and ion release. European Journal of Orthodontics 2017, 39 (1), 9-16

[0061] Metin-Gursoy, G.; Taner, L.; Akca, G., Nanosilver coated orthodontic brackets: in vivo antibacterial properties and ion release. Eur J Orthod 2017, 39(1), 9-16

[0061] Arash, V.; Keikhaee, F.; Rabiee, S. M.; Rajabnia, R.; Khafri, S.; Taveanafar, S., Evaluation of Antibacterial Effects of Silver-Coated Stainless Steel Orthodontic Brackets. J Dent (Tehran) 2016, 13 (1), 49-54

[0061] Coordinates, S. L.; Jost-Brinkmann, P. G.; Prager, T. M.; Bartzela, T.; Visel, D.; Jacker, T.; Muller-Hartwich, R., A comparison of different sealeds preventing demineralized around brackets. Journal of orofacial orthopedics= Fortschritt of orthodontics: Organ / official journal Deutsche Gesellschaft fur Orthodontics 2018, 79 (1), 49-56.

[0061] Derks, A.; Katsaros, C.; Frencken, J. E.; van't Hof, M. A.; Kuijpers-Jagtman, A. M., Caries-inhibiting effect of preventive measures during orthodontic treatment with fixed appliances. A systematic review. Carries Res 2004, 38 (5), 413-20

[0061] Bechtold, T. E.; Sobiegalla, A.; Markovic, M.; Berneburg, M.; Goz, G. R., In vivo efficacy of enamel sealed sealed orthodontic brackets. Journal of orofacial orthopedics= Fortschritt of the orthodontics: Organ / official Journal Deutsche Gesellschaft fur Orthodontics 2013, 74 (6), 447-57

[0061] Kamber, R.; Meyer-Luckel, H.; Kloukos, D.; Tennert, C.; Virichs, R.J., Efficacy of sealeds and bonding materials during fixed orthodontic treatment to prevent enamel demineralized: a systematic review and meta-analysis. Sci Rep 2021, 11 (1), 16556

[0061] Hannig, C.; Hannig, M., The oral cavity-a key system to inferior substrate-dependent bioadhesion on solid surfaces in man. Clinical oral investigation 2009, 13 (2), 123-39

[0061] Oliveira, A. S.; Kaizer, M. R.; Azevedo, M. S.; Oglari, F. A.; Cenci, M. S.; Moraes, R. R., (Super)hydrophobic coating of orthodontic dental devices and reduction of early oral biofilm retention. Biomedical materials 2015, 10(6), 06004

[0061] Ryu, H. S.; Bae, I. H.; Lee, K. G.; Hwang, H. S.; Lee, K. H.; Koh, J. T.; Cho, J. H., Antibacterial effect of silver-platinum coating for orthodontic appliances. The angle orthodontist 2012, 82 (1), 151-7

[0061] Ramazanceadeh, B.; Jahanbin, A.; Yaghoubi, M.; Shahthmassbi, N.; Ghazvini, K.; Shakeri, M.; Shafaee, H., Comparison of Antibacterial Effects of ZnO and CuO Nanoparticles Coated Brackets against Streptococcus Mutans. J Dent (Shiraz) 2015, 16 (3), 200-5

[0061] Chambers, C.; Stewart, S.; Su, B.; Sandy, J.; Ireland, A., Prevention and treatment of demineralized during fixed application therapy: a review of current methods and future applications. British Dental Journal 2013, 215 (10), 505-11

[0061] Cao, S.; Wang, V.; Cao, L.; Wang, V.; Lin, B.; Lan, W.; Cao, B., Preparation and antimicrobial assay of ceramic brackets coated with TiO2thin films. Korean J Orthod 2016, 46 (3), 146-54

[0061] Zhang, R.; Zhang, W.; Bai, X.; Song, X.; Wang, C.; Gao, X.; Tian, X.; Liu, F., Report: Disclosure on the development of nano Ag / TiO2coating bracket and its antibacterial property and biocompatibility in orthodontic treatment. Pak J Pharm Sci 2015, 28 (2 Suppl), 807-10

[0061] Rongo, R.; Valletta, R.; Bucci, R.; Rivieccio, V.; Galeotti, A.; Michellotti, A.; D'Anto, V., In vitrobiocompatibility of nickel-titanium ethetic orthodontic archwires. The angle orthodontist 2016, 86 (5), 789-95

[0061] da Silva, D.L.; Mattos, C.T.; Simao, R.A.; de Oliveira Ruellas, A.C., Coating stability and surface characteristics of ethotic orthodontic coated archives. The angle orthodontist 2013, 83 (6), 994-1001

[0061] Epperlein, N.; Menzel, F.; Schlibert, K.; Kater, R.; Bonse, J.; Sameh, J.; Kruger, J.; Toepel, J., Influence of femtoscond laser produced nanostructures on biofilm growth on steel. Appl Surf Sci 2017, 418, 420-424

[0061] Groenendijk, Max. "Fabrication of Super Hydrophobic Surfaces by fs Laser Pulses: How to Produce Self-Cleaning Surfaces." Laser Technology Journal 5.3 (2008): 44-47

[0061] Peter, A., Lutey, A.H., Faas, S., Romoli, L., Onuseit, V., & Graf, T. (2020). Direct laser interference patterning of stainless steel by ultrashort pulses for antibacterial surfaces. Optics & Laser Technology, 123, 105954

[0061]

Claims

Orthodontic bracket, wherein the bracket has at least one antibacterially active surface, wherein the antibacterially active surface is a structured surface (42) or a surface (43) chemically modified by binding a pharmaceutical active substance.Bracket according to claim 1, characterised in that it has a plate for connection to a tooth and a base body, wherein the surfaces of the base body are antibacterially active surfaces.The bracket of claim 2, characterized in that the plate has a surface for connection to the tooth and at least one further surface, wherein the surface for connection to the tooth is not an antibacterially effective surface and wherein the further surface is an antibacterially effective surface.The bracket according to any one of the preceding claims, characterized in that the structured surface (42) has a roughness in a range from 10 nm to 100 μm Sa.The bracket according to any of the preceding claims, characterized in that the structured surface (42) is a hydrophobic or a superhydrophobic surface.Bracket according to one of the preceding claims, characterized in that the structured surface (42) has a contact angle in a range from 90° to 180° when wetted with water.Bracket according to one of the preceding claims, characterized in that the structured surface (42) has a contact angle in a range from 140° to 180° when wetted with water.The bracket of any preceding claim, wherein the structured surface (42) is a metal surface.The bracket according to any one of the preceding claims, characterized in that the structured surface (42) has a surface structure which, starting from the base surface (41) of the bracket, has depressions.The bracket according to claim 9, characterized in that the depressions have a depth in a range from a few nanometers to a few 10 micrometers and / or a width from a few nanometers to a few 10 micrometers, starting from the base surface (41) of the bracket.The bracket according to any one of the preceding claims, characterized in that the structured surface (42) has a surface structure, wherein the surface structure has a periodic structure with a periodicity in a range from 1 to 50 μm.Bracket according to one of Claims 1 to 4, characterized in that the surface (43) which is chemically modified by bonding a pharmaceutical active substance has an anchor unit via which the active substance is bonded to a base surface (41) of the bracket.The bracket of claim 12, characterized in that the anchor moiety is a copolymer.A method of making an orthodontic bracket having at least one antibacterially active surface according to any one of claims 1 to 12, the method comprising forming an antibacterially active surface by altering a base surface of the bracket.Method according to claim 14, characterised in that it comprises structuring the base surface of the bracket with a laser in order to produce the antibacterially active surface.

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