Use of an aqueous solution of an acid as a treatment fluid for cleaning an implant component

Abstract

Use of an aqueous solution of an acid containing a metal salt such that a conductivity of at least 30 mS / cm is obtained, as a treatment fluid for cleaning bacterially contaminated surfaces of bone implants or dental implants.

Description

[0001] The invention relates to the use of an aqueous solution of an acid as a treatment fluid, in particular for cleaning bacterially contaminated surfaces of bone implants, dental implants, or other components contaminated with biofilm. It further relates to such use for cleaning a dental implant component inserted into the jawbone of a patient.

[0002] In principle, such treatment fluids are known from a wide variety of sources, for example DE 26 00 498 A1, DE 10 2007 045 210 A1, DE 16 17 156 C2, EP 2 031 048 A1, DE 197 10 127 A1, US 4 124 522 A, DE 698 16 219 T2, JP 2008-214 591 A, US 3 420 760 A or JP H08-299 999A. However, the application range of such fluids is largely limited to the cleaning of machine parts and components.

[0003] From the unpublished German patent application number 10 2012 022 593.8, the disclosure of which is fully incorporated by reference, a treatment element, particularly for use with an implant component, and a method for cleaning a dental implant component are known. A biofilm can form on the solid surface of implants, which is surrounded by tissue and tissue fluid. This biofilm is colonized by bacteria, which can ultimately lead to chronic and recurring infections. This condition is known as peri-implantitis.Particularly in dentistry, similar to periodontitis, a combination of neglected oral hygiene, biofilm adhesion to the typically micro-rough surface of the abutment, and other factors is responsible for the full clinical picture of peri-implantitis, which is characterized by increasing stress and destruction of the hard and soft tissues. The areas where the hard and / or soft tissue recedes are usually covered with a biofilm.

[0004] The cleaning process described in the aforementioned application is based on the concept of killing and removing the contaminant-causing biofilm or germs from the implant surface without damaging the implant surface. This is achieved through an electrolytic process in which ions (cations and / or anions) are transported through the biofilm by means of electrostatic forces. These ions react chemically or electrochemically at the implant surface. These reactions create new compounds and / or convert the ions themselves and / or parts of these ions into an atomic state. Furthermore, there is also the possibility that the ions react with the surface material (e.g., forming an oxide layer or material abrasion).

[0005] The germicidal effect of this process is based on various mechanisms. Firstly, applying an electrical voltage transports ions from the biofilm itself (including those from the bacteria) to the anode or cathode. This can lead to the killing of bacteria and viruses. Furthermore, as the ions pass through the biofilm, they can undergo biochemical reactions, which can also kill bacteria and / or viruses. Another possibility for killing is that the compounds newly formed on the implant surface possess antibacterial, antiviral, and / or antifungal properties. This can also occur when the ions break down into their atomic state. With all the processes described above, there is an inherent risk that toxic, cell-damaging, and / or bone-damaging substances or compounds could be formed or released.

[0006] The present invention is based on the objective of specifying the use of a treatment fluid that is particularly suitable for the aforementioned treatment system. In particular, a treatment fluid is to be specified that is especially suitable and highly effective for the treatment or cleaning of components of a dental implant system, other implant parts, such as bone implants in general.

[0007] This problem is solved according to the invention by using a treatment fluid which is formed as a basic component of an aqueous solution of an acid which is provided with a metal salt such that a conductivity of at least 30 mS / cm, preferably at least 75 mS / cm and particularly preferably at least 150 mS / cm is obtained.

[0008] Advantageous embodiments of the invention are the subject of the dependent claims.

[0009] The invention is based on the consideration that a suitable treatment fluid should, on the one hand, be specifically designed to utilize and promote the effects of electrolytic cleaning in the aforementioned system, while, on the other hand, particularly with regard to the potential use of the fluid for cleaning implant components in the inserted state, the formation of toxic, cell-damaging, and / or bone-damaging or generally hazardous substances should be consistently avoided or at least reduced to a clinically acceptable level. To enable this, the treatment fluid is specifically designed to be suitable as an electrolyte for the aforementioned electrochemical processes, in particular by providing a suitably selected conductivity.On the other hand, the treatment fluid is also selected with regard to the choice and composition of its basic components in such a way that the substances present in the fluid and also the products generated during the electrochemical processes particularly promote germ killing and, if necessary, the mechanical removal of the biofilm, without causing any significant damage or risks to the body or bone tissue.

[0010] Advantageously, the metal salt is a salt of aluminum, an alkali metal, or an alkaline earth metal, in particular a potassium, sodium, magnesium, or calcium salt. A potassium or sodium salt is especially preferred. Chlorine or iodine is also advantageously used as the salt-forming agent for the metal salt. The acid, on the other hand, is particularly preferably an organic acid, most preferably an α-hydroxycarboxylic acid, preferably lactic acid, citric acid, acetic acid, malic acid, or a combination of these components. A particularly advantageous composition of the basic components is achieved when—for the purpose of pH buffering to compensate for hydroxide production as needed—the pH of the treatment liquid is less than 5, preferably less than 4, and most preferably about 2.7 to 2.9.

[0011] The treatment fluid is particularly advantageous and used in an independently inventive manner for cleaning bacterially contaminated surfaces of bone implants and dental implants.

[0012] The advantages achieved with the invention lie particularly in the fact that the combination of the basic components, metal salt and acid, and the associated electrical conductivity due to the ion density, can particularly promote the desired electrolytic or electrochemical processes during purification. In particular, the acid can counteract an undesirable increase in pH value resulting from the reaction-induced formation of metal hydroxide by acting as a pH buffer.

[0013] An embodiment of the invention is explained in more detail with reference to a drawing. The drawing shows: Fig. 1 a two-part dental implant system in assembled state, Fig. 2 the dental implant system according to Fig. 1 in exploded view, Fig. 3 the post part of the dental implant system according to Fig. 1, Fig. 2 in side view, Fig. 4 the post part according to Fig. 3 in longitudinal section, Fig. 5 a treatment element for the post part according to Fig. 3, Fig. 4 in perspective view, Fig. 6 the treatment element according to Fig. 5 in longitudinal section, Fig. 7, Fig. 8 each an alternative embodiment of a treatment element in perspective view, Fig. 9 the treatment element according to Fig. 8 in longitudinal section, and Fig. 10 a treatment system.

[0014] Identical parts are marked with the same reference symbols in all figures.

[0015] The treatment fluid according to the invention is explained in more detail here with reference to a use considered preferred in a treatment system for a dental implant, but is in no way limited to this use. Rather, analogous use for the treatment or cleaning of other components of a dental implant system, other implant parts such as, for example, bone implants in general, is also conceivable.

[0016] The dental implant system 1 according to Fig.The dental implant system 1 is designed for insertion into the jawbone in place of an extracted or missing tooth to support a prosthetic component or crown. The system is multi-part and comprises a first implant component 2, also known as a post, and a second implant component 4, also called an abutment, which is designed to support a prosthetic tooth. The first implant component 2, or post, has an external thread 6, which is a self-tapping screw thread, particularly at the apical end 8. This allows the first implant component 2, or post, to be inserted into the jawbone at the designated location by screwing it in.

[0017] To enable insertion of the dental prosthesis or denture into the post or first implant part 2 with high mechanical stability after suitable attachment to the abutment or second implant part 4, a connecting pin 10 is molded onto the second implant part 4. This connecting pin can be inserted into a corresponding receiving channel 12 provided in the first implant part 2. Inserting the connecting pin 10 into the receiving channel 12 creates a mechanical connection between the implant parts 2 and 4. For high mechanical stability, the outer contour of the connecting pin 10 is adapted to the inner contour of the receiving channel 12, with both potentially being conically shaped in the longitudinal direction (exemplary embodiment according to [reference to figure]). Fig. 2) Furthermore, as is particularly evident in the embodiment shown in the following Fig.3. The outer contour of the connecting pin 10 – and, accordingly, the inner contour of the receiving channel 12 – is designed in cross-section with multiple (in the exemplary embodiment, sixfold) symmetry, so that when the aforementioned components are joined, a rotational locking mechanism is created, thus enabling reliable rotational alignment of the superstructure relative to the post section. In the exemplary embodiment according to Fig. 3, Fig. 4 For this purpose, an indexing element 14 with a cross-section with multiple symmetry is arranged at the end of the connecting pin 10 for indexing or for forming a rotary locking mechanism, which in the assembled state engages in a corresponding, associated end channel piece 16 in the receiving channel 12.

[0018] In the exemplary embodiment, the dental implant system 1 is designed for a screw connection between the implant parts 2 and 4. For this purpose, a connecting screw 18 is provided for each part, which engages in a screw thread 20 provided within the first implant part 2. With regard to their material selection, the implant parts 2 and 4 are suitable for their intended use and are generally made of ceramic material such as zirconium oxide or aluminum oxide, or of a suitable metal such as titanium.

[0019] In general, dental implant systems, especially two-piece implant systems of the type described above, present the problem that the penetration of bacteria or germs into the tissue near the insertion site, particularly in the area of ​​the external thread 6 inserted into the jawbone, can lead to inflammation or foci of infection. Such inflammation, especially that resulting from so-called peri-implantitis, can, particularly if it develops and hardens over a longer period, lead to serious damage to the tissue and bone at the insertion site. Without appropriate countermeasures, this damage can necessitate the removal of the entire implant system, including the already inserted abutment or second implant part 4, from the bone and its replacement with a different prosthesis.This highly undesirable effect caused by peri-implantitis can lead to the total loss of the implant system, necessitating further surgical procedures such as bone resection of the affected area and placement of a new implant system. Such removal can also result in bone loss or other tissue loss, which in extreme cases can make placement with a different implant impossible. This need for replacement due to peri-implantitis can occur even after a relatively long period following the initial placement of the implant system, for example, several years or even decades.

[0020] The germs or bacteria observed in connection with peri-implantitis can, in principle, colonize the interior of the abutment 2, but they usually adhere preferentially directly to the surface of the abutment 2 inserted into the jawbone in the contact area with the surrounding tissue or bone material, i.e., particularly in the area of ​​the external thread 6. In this area, the surface of the abutment 2 may be roughened or similarly textured to promote ingrowth into the tissue or bone and to support the healing of the abutment 2 after insertion. However, precisely in the area of ​​such surface roughening, which is actually considered particularly beneficial for the implant system, the colonization of germs or bacteria can occur more frequently, and the roughness further complicates the targeted removal of the existing germs or bacteria.

[0021] There is therefore an urgent need for suitable countermeasures to effectively combat the source of inflammation and kill the invading pathogens in the event of incipient or existing peri-implantitis, while preserving the already inserted implant system, and in particular the already inserted abutment 2. This would allow healthy tissue or bone to regenerate around the external thread 6. In addition to the targeted elimination of the pathogens or bacteria in the affected area, it is desirable to reliably remove their material remnants and fragments from the affected space. This would allow the affected area to be refilled with healthy tissue or bone material, and a strong bond could be re-established between the outer surface of the abutment 2 and the surrounding tissue or bone.Furthermore, the biofilm formed by the bacterial coating, including the organic remains of killed bacteria, should be reliably removed.

[0022] For this purpose, i.e., to kill germs or bacteria in the insertion area of ​​the post part 2 and in particular also for the subsequent rinsing, removal and disposal of the tissue and material residues of the killed bacteria, a treatment element 30 is provided, as shown in perspective view in Fig. 5 and in longitudinal section in Fig.Figure 6 is shown. In the exemplary embodiment, the treatment element 30 is designed in the form of a treatment abutment due to the two-part design of the implant system 1 and is intended for carrying out the treatment mentioned for the two-part implant system 1 shown, whereby the treatment abutment 30 is to be temporarily placed on the post part 2 instead of the actual abutment or second implant part 4.The following explanations therefore refer to this case of a two-part implant system 1; however, a corresponding use for one-piece implants can, of course, also be provided in an analogous design; for this purpose, the mechanical connection of the treatment element 30 with the part of the implant system that remains in the jawbone during treatment would simply need to be appropriately designed, for example, via a suitable contact surface with which the treatment element 30 can be placed on the abutment of the implant instead of the prosthesis. Alternatively, the treatment element 30 can also be placed on top of the actual abutment 4 of the implant system 1, so that its use, for example, for combating inflammation of the soft tissue (mucositis) by killing the bacteria and cleaning the surface can be provided without having to remove the actual abutment 4.

[0023] In the two-part design of the implant system 1 as described in the exemplary embodiment, the following procedure is carried out by first loosening the screw connection between the first and second implant parts 2, 4 – if necessary, after removing the prosthesis attached to the actual abutment or second implant part 4 – and then removing the second implant part 4. The first implant part or post part 2 remains in the jawbone. The treatment abutment 30 is then placed onto the post part 2 in place of the actual abutment 4 and connected to it via the screw connection. The treatment element 30 has a substantially flat contact surface 32 with which it can be placed onto the end face 34 of the post part 2. The contact surface 32 can also function as a sealing surface and be designed accordingly; in particular, it can be conical for this purpose.

[0024] The treatment abutment 30 is based, with regard to its design and basic construction, on the fundamental concept of selectively killing germs or bacteria present in the insertion area of ​​the post part 2 by targeted application of a cleaning or disinfecting agent, whereby any remaining residues or fragments of germs and / or bacteria adhering to the surface of the post part 2, particularly in the area of ​​the external thread 6, are to be detached from the outer surface of the post part 2 by suitable application of current or electric shocks, so that they can subsequently be washed away.

[0025] In a first aspect, both with regard to the design of the system and with regard to the intended process steps of the treatment procedure, the treatment element 30 is therefore designed both structurally and functionally / conceptually to feed a treatment fluid for killing germs or bacteria and / or for cleaning the inserted implant part 2 specifically into the insertion area of ​​the post part 2, in particular the area of ​​its external thread 6.

[0026] In a second aspect, also concerning the design of the system, the selection and composition of the basic components of the treatment fluid used, and the planned procedural steps of the treatment process, the treatment element 30 is designed to reliably detach the killed bacteria or germs, or their remnants or fragments, from the outer surface of the post part 2, so that they can subsequently be rinsed away and healthy tissue or bone material can then adhere to the surface of the post part 2 and be completely integrated into healthy tissue or bone material. The detachment of the bacteria or germs, or their remnants or fragments, from the surface is achieved by wetting them with a conductive treatment fluid while applying an electric current, possibly in the form of pulsed current pulses.As has also turned out to be quite surprising, this application of electricity in combination with appropriately chosen ion concentrations in the treatment fluid seems to reliably cause the detachment of bacteria or germs, or their fragments or remains, from the underlying surface, even if this surface is rough and actually particularly promotes the adhesion of organic material due to its surface structure.

[0027] The underlying, surprising finding is that applying an electric current to post section 2 using a suitably selected treatment fluid in the area of ​​the post section's outer surface, particularly in the area of ​​the external thread 6, leads to an electrolytic reaction in the treatment fluid and thus potentially to the generation of gas bubbles in the immediate vicinity of the surface. This gas bubble formation on the surface of post section 2 detaches and completely removes the surface-adhering components or fragments of germs or bacteria, preventing them from forming a base or breeding ground for new germ colonization in these areas. What remains is a roughened and porous surface of post section 2, free of germs, bacteria, or their components or residues, which can serve as a suitable base for future integration into the regrowing bone tissue.The remaining surface may also consist of a titanium oxide layer, which would also be formed by anodizing the surface.

[0028] A particularly advantageous method for promoting the removal of biofilm components adhering to the surface from the inserted post section 2, which is desirable for reliable surface cleaning, can be achieved through a particularly suitable process during the application of current. This process can be designed to particularly enhance the electrolytic gas bubble formation occurring in the area of ​​the inserted surface as a result of the current flow. The post section 2 can be connected anodically or cathodically. In particular, with at least temporary cathodic connection of the post section 2, electrolytically induced hydrogen gas is produced, which contributes particularly effectively to gas bubble formation. With anodic connection of the post section, on the other hand, chlorine gas, oxygen, nitrogen, carbon monoxide, and / or carbon dioxide are produced, depending on the composition of the treatment fluid.The resulting gas bubbles rise in the surrounding liquid, creating entrainment effects that carry away the aforementioned surface components and transport them outwards. For example, it was observed quite unexpectedly that when using a solution containing positive ions, such as an aqueous salt solution, these ions are deposited on the post section 2 when cathodically connected, thus significantly increasing gas bubble formation. For example, the presence of Na + -Ions in cathodic connection of post part 2 lead to significant gas bubble formation, since Na+ reacts at the cathode to form elemental Na, which in turn reacts with the surrounding water to form NaOH, releasing hydrogen in the process.

[0029] In a third aspect, also concerning both the system design and the intended process steps of the treatment procedure, treatment element 30 is designed for a particularly simple and efficient combination of the aforementioned aspects. The underlying concept is that both the intended supply of the cleaning fluid and the targeted removal of bacterial and germ residues and fragments by applying the aforementioned current can be achieved in a single system and thus with particularly simple means.

[0030] The treatment fluid according to the invention is suitably selected and composed with regard to these aspects. The selection and composition of the basic components of the treatment fluid are carried out particularly with regard to the intended mode of action, i.e., the application of an electric current in the spatial region of the surface requiring treatment, whereby it is ensured in particular that a sufficiently high electrical conductivity is present in the treatment fluid for this purpose. This is to be ensured in particular by a sufficiently high ion density in the treatment fluid. For this purpose, a metal salt is provided as a basic component of the treatment fluid, preferably in aqueous solution. This provides the ions for current transport, and in addition, the reaction products formed after the respective electrode reaction can also exhibit suitable biochemical effects.By selecting a sufficiently high electrical conductivity, the cleaning procedure on the inserted implant is designed to ensure that the current flows through the treatment fluid and thus through the parts and components requiring treatment, but not through the patient's body tissue. This minimizes the risk to the patient from an unwanted current flow through soft tissue, bone, blood, and / or other bodily materials. The electrical conductivity of the treatment fluid should ideally be several times higher than that of blood, bone, soft tissue, fatty tissue, or other bodily materials.

[0031] Accordingly, the following conductivity values ​​are taken into account in the selection and composition of the basic components for the treatment fluid (the electrical conductivity σ is given in the usual unit mS / cm): Skin: 0.03 - 0.1 mS / cm Bone: 0.06 - 0.2 mS / cm Fat tissue: 0.20 - 1.0 mS / cm Muscle tissue: 0.80 - 2.5 mS / cm Blood: approx. 6.7 mS / cm other bodily fluids: approx. 15 mS / cm

[0032] To keep the potential risk to the patient suitably low and to limit the current flow to the desired regions, the electrical conductivity should therefore be at least twice, preferably five times, and particularly preferably ten times that of other body fluids. Therefore, the electrical conductivity of the treatment fluid should be at least 30 mS / cm, preferably at least 75 mS / cm, and particularly preferably at least 150 mS / cm. Compared to blood, this means that the electrical conductivity of the treatment fluid is preferably at least about five times, preferably at least about ten times, and particularly preferably at least about twenty times that of blood. Measurements have shown that when using a treatment fluid selected in this way, the electrical voltage applied to the body tissue, blood, body fluids, etc., is significantly reduced.The voltage at which the patient is exposed to the treatment fluid is less than 6 V, preferably less than 3 V, and particularly preferably less than 1.5 V. This ensures that damage to the patient due to the low voltages can be reliably ruled out. To maintain such a conductivity, the ion concentration in the treatment fluid and its constituent components is selected to be sufficiently high; alkalis, acids, salts, and / or other ion-forming substances or compounds can be used for this purpose.

[0033] When selecting and composing the basic components of the treatment fluid, particular attention is paid to the fact that the cleaning or biofilm-removing effect of electrolytic treatment of a contaminated implant surface is based on a combination of several factors, which should be utilized in a complementary manner whenever possible. Firstly, gases or gas bubbles can form preferentially in the area of ​​the electrodes when current flows through the electrolyte. These gases have a lifting (mechanical) effect on the biofilm. The formation of these gases occurs directly at the implant surface serving as the electrode, and thus between the implant surface and the biofilm. The growth rate and maximum size of the resulting gas bubbles influence the removal process.

[0034] A second reason for the electrolytic process's effect on cleaning the implant or removing the biofilm is the decomposing, destructive, and dissolving effect of the electrolytically produced substances or compounds on the actual adhesion of the biofilm to the implant surface, i.e., on the adhesive or anchoring mechanism.

[0035] The third cause for the cleaning or removing effect of the electrolytic process is based on material-abrasive effects of the implant material, whereby components or particles of the actual implant are removed from its surface area.

[0036] The fourth reason for the cleaning or dissolving effect of the electrolytic process is based on the oxide layer formation of metallic implants that allow this. Here, metal atoms of the metallic base material penetrate any existing oxide layer based on the applied electrical voltage and react with substances in the electrolyte (mostly oxygen => metal oxide formation). In the case of metals that do not form an oxide layer, or at least not a mechanically stable one, non-oxide compounds (mostly salts) can also form, which then dissolve into the solution.

[0037] The basic components intended for the formation of the treatment fluid are suitably selected and combined with regard to these effects. Furthermore, a fundamental design objective is that no toxic or otherwise harmful or unpleasant effects should occur for the patient, so that the treatment fluid is also suitable for use on the inserted dental implant, i.e., in the patient's mouth. In the exemplary embodiment, the basic components consist of at least one salt on the one hand and one acid on the other, preferably diluted with water, the selection and composition of which are determined in particular by the aforementioned criteria. Phosphoric acid, citric acid, malic acid, acetic acid, lactic acid, carbonic acid, or a combination thereof are particularly preferred as the acid.Alternatively or additionally, sodium, calcium, aluminum, magnesium or potassium iodide, chloride, nitrate, carbonate or hydrogen carbonate and / or ammonium chlorite, nitrate or iodide or a combination thereof are particularly preferred as the salt.

[0038] Furthermore, it is taken into account that the intended electrolytic process can be carried out with either anodic or cathodic connection of the post section. Therefore, the following section divides the process into an anode reaction and a cathode reaction.

[0039] In an anode reaction, i.e., when the post part 2 is connected anodically, the anions present in the treatment fluid are generally oxidized at the anode by the removal of electrons. This can lead to a direct reaction with the material, in particular the formation of an oxide layer and / or a salt with the implant material. Bone implants, and consequently also post part 2, are usually made of titanium, zirconium, tantalum, or alloys of these metals. Other metals are also often added. These metals or metal alloys typically exhibit a high degree of oxide layer formation. This oxide layer formation has a passivating effect on the surface. The result is the inhibition, or at least a significant reduction, of the anode reaction of these metals or metal alloys. Since biofilms usually contain compounds with oxygen, preventing this passivation is generally not possible.If the post component is anodically connected, the abrasive cleaning effect is usually limited to oxide layer formation. Extensive studies have shown that at higher operating voltages, for example above 10 V, a material removal process is possible, but this is associated with significant heat generation. This heat generation can lead to undesirable bone necrosis. Furthermore, the resulting material removal also undesirably alters the properties of the original implant surface.

[0040] As an exception to this, it has surprisingly been shown that with a base material of post part 2 in which aluminum is present as an alloying element (for example, titanium grade 5, which has approximately 6% aluminum and 4% vanadium content), anodic current can also be applied to post part 2 without the formation of an oxide layer significantly hindering the process. Depending on the composition of the treatment fluid, this allows chlorine or iodine gas, or even CO2, to be generated directly on the surface of post part 2 and thus used directly for the desired biofilm removal. For such a process, the treatment element 30 is particularly advantageously provided with a conductive surface coating, for example, made of DLC (diamond-like carbon), a metal, conductive plastic, or an electrically conductive ceramic.

[0041] It has proven particularly advantageous that, with a base material of titanium grade IV or titanium grade V for the post part, the addition of CO2 to the treatment fluid allows for CO2 formation, Cl formation and / or I formation despite the formation of an oxide layer during anodic current application, enabling a longer-lasting current flow.

[0042] For the reasons mentioned above, post part 2 is generally preferably connected cathodically during treatment with the treatment fluid. In this case, positively charged ions (cations) migrate to the surface of post part 2. These can be, in particular, H₂ +These can be ions, metal ions, or long-chain hydrocarbon ions, e.g., from ionic liquids. The salt intended as the basic component for the treatment fluid is specifically selected with regard to the properties of the cations that are intended to promote or even enable the aforementioned process. Small ions (H₂) are particularly suitable for generating the highest possible electrical conductivity. + -ions or metal cations), which, in addition, can penetrate any existing biofilm relatively easily, resulting in another particularly beneficial effect. H +Hydrogen ions are reduced to elemental hydrogen (H) at the cathode formed by post part 2. This produces bubbles. Another cathode reaction is the deposition of elemental metals. However, most metals would deposit as a continuous metallic coating. This would be an undesirable effect, as this coating would have unfavorable adhesion properties and unfavorable chemical (electrochemical and biochemical) properties.

[0043] For the reasons mentioned above, metals whose cations pose no biological risk to the patient and which, in their elemental state, exhibit the strongest possible chemical reaction with water in the electrolyte are preferred for the cathode reaction at the implant surface. Alkali metals, noble metals, and / or aluminum react directly with the surrounding water via electrolytic reduction at the cathode to form elemental hydrogen and its metal cations, as well as OH. - -ions. This means that hydrogen bubbles and the hydroxide of the metal ion used are formed. The combination of these components thus achieves not only the dissolving effect of the generated hydrogen, but also that the metal hydroxide has an antibacterial effect and exerts a thinning or dissolving influence on the biofilm or its adhesion mechanism.

[0044] To avoid incompatibilities with body tissue, endogenous metal cations (e.g., potassium and / or sodium ions) are particularly preferred. Calcium, magnesium, and / or aluminum ions are also suitable. The salt intended as the basic component of the treatment fluid is therefore preferably a salt of these metals, especially since these metal cations can only be provided in salt form, e.g., dissolved in water.

[0045] These metal salts can be compounds of the aforementioned metals with a suitable salt-forming agent, such as sulfur, phosphorus, nitrogen, fluorine, chlorine, iodine, bromine, hydrocarbons, oxygen, boron, or other nonmetals. The salt-forming agent is advantageously selected taking into account the principle "the larger the anion, the lower the electrical conductivity" and with regard to the generally desired high electrical conductivity. Furthermore, only substances that do not affect health or peri-implant tissue are preferably considered as anions. It should also be noted that unpleasant odors or tastes are undesirable. For these reasons, sulfur anions or anions containing sulfur in combination with oxygen or other elements are considered rather unsuitable.This also applies to fluorine, bromine, nitrogen, and boron ions, possibly in combination with other elements.

[0046] In contrast, phosphates, phosphate ions, and hydrogen phosphate ions usually have little to no harmful effect. Chloride ions, or ions containing chlorine, generally have an antibacterial effect. However, if the chloride ion is electrolytically oxidized and is present in water in its elemental form, hydrochloric acid and hypochlorous acid are formed. While this would lead to neutralization in combination with the cathodically generated hydroxide, studies have shown that a large amount of the chlorine produced at the counter electrode to the implant (anode) escapes from the electrolyte as a gas. If the chlorine cannot be completely aspirated during treatment, severe burns to the lungs and / or mucous membranes can occur. In such cases, a careful assessment must be made to weigh the benefits to the patient against the risks.

[0047] Regarding the phosphates of aluminum, potassium, sodium, calcium, or magnesium, it should be noted that their solubility in water is so low that sufficient electrical conductivity of the electrolyte is not guaranteed (however, these phosphates are very suitable as electrolyte additives for buffering the pH). Chlorides of the four metals listed above would have sufficient solubility in water and a good cleaning and biofilm-killing effect, but cannot be considered optimal. With nitrates and / or nitrites, there is a risk to the patient due to the formation of NO. x -gases are to be expected. For this reason, the use of nitrites or nitrates is not recommended.

[0048] With regard to the aforementioned design objectives, particularly for optimal patient tolerance, iodine is preferably used as the salt-forming agent. A particular advantage is that iodine salts of potassium and sodium are also naturally present in the human body. During the oxidation of iodide ions at the anode, elemental iodine is initially produced, which can dissolve in a sodium iodide / potassium iodide solution. This results in an iodine-potassium iodide solution or an iodine-sodium iodide solution. Both solutions are powerful disinfectants that have proven effective in human medicine.

[0049] Pure sodium or potassium iodide solutions, or a mixture of both, have the potential disadvantage of forming sodium and / or potassium hydroxide and the associated increase in pH. The formation of metal hydroxide, as described above, could be problematic because it raises the pH of the electrolyte. Such an elevated pH and the resulting alkali or base from the dissolved metal hydroxide could have an undesirable effect on the surrounding tissue in the patient's mouth, particularly the bone. Adjacent teeth could also be damaged. Furthermore, the formation of hydroxides, due to their very low water solubility, could cause them to deposit on post part 2 or on the component requiring treatment, thereby impeding the flow of current and thus hindering the entire process.Only if a calcium salt is used in the treatment fluid could the resulting calcium hydroxide, which occurs as a component of bone material, be incorporated into the bone; calcium is therefore a particularly favored component of the salt. To compensate for these undesirable effects, the treatment fluid contains acid as a further basic component, acting as a pH buffer or reducer.

[0050] The acid is specifically chosen as a design criterion to minimize risks to the patient or peri-implant tissue. Its primary function is to neutralize the hydroxide (and prevent the pH from rising above 7), while the reaction products should serve the primary purpose of cleaning the implant body and removing the biofilm. Phosphoric and / or phosphatic acids are preferred mineral acids for this purpose. Their concentration should be limited to a maximum of 30%, or preferably 10 to 20%, to avoid health risks and / or potential damage to bone and tissue. Carbonic acid, also considered a mineral acid, is a particularly favored acid that has a particularly positive effect on the overall goal of biofilm destruction and cleaning.However, the amount that can be used is limited by its comparatively low solubility in water.

[0051] In contrast, organic acids, like mineral acids, act as pH-reducing and hydroxide-neutralizing agents. +-ions are available. Since they also cause no or only minimal damage to the tissue or to the patient as a whole, such organic acids are particularly preferred as a basic component for the treatment fluid. Organic acids include, for example, alkanoic acids, fruit acids, carboxylic acids, and hydroxylcarboxylic acids. α-Hydroxylcarboxylic acids have proven to be particularly suitable. In particular, the especially preferred acids lactic acid, citric acid, and malic acid show no harmful effects on the patient in general or on the peri-implant tissue. Especially in the case of implants heavily coated and contaminated with biofilm, on which tartar has also formed, even comparatively low doses of acetic acid have shown good cleaning results.Other acids that have cleaning and antibacterial effects, but are not harmless for health reasons, would be fumaric acid, gluconic acid, glycolic acid, salicylic acid, mandelic acid, tartaric acid, oxalic acid and formic acid.

[0052] During the neutralization of the hydroxide ion OH - with the corresponding H +When an acid reacts with a ion, the metal salt of the corresponding metal hydroxide is also formed. The intended use of the acid is therefore not only advantageous for buffering the pH value, but also contributes to the conversion of the relatively poorly water-soluble hydroxide into relatively well-soluble salts, thus preventing the deposition of unwanted precipitates on the component requiring treatment, which would hinder the process. These salts are used, particularly in combination with the aforementioned preferred materials, also in medicine. When potassium, sodium, and / or calcium hydroxide is neutralized with lactic acid, potassium lactate (which possesses a broad-spectrum antimicrobial effect), sodium lactate, or calcium lactate is formed. If, however, the hydroxides formed are neutralized with citric acid, potassium, sodium, or calcium citrates are formed.This is particularly advantageous for sodium citrate, as it prevents blood clotting. This is especially beneficial because blood leaking out during the process and clotting on the implant surface could hinder the migration of ions to the implant surface and thus impede the continuation of the treatment process as a whole.

[0053] In contrast, the neutralization of hydroxides with malic acid produces malates of the respective cation, which also have a beneficial effect on the process. The neutralization of hydroxides with acetic acid produces acetates of potassium, sodium, and / or calcium, which also have a beneficial effect on the process.

[0054] The lactates, citrates, malates and / or acetates of potassium, sodium and / or calcium all have an acid-regulating effect and are so well tolerated that, according to current EU regulations for food additives, their use is not subject to any quantity limitations.

[0055] When using acids in the electrolyte in combination with iodides and / or chlorides of sodium, potassium, magnesium, aluminum and / or calcium, it has surprisingly been found in electrolytic applications that the direct reduction of the H +The presence of these ions positively influences bubble formation, resulting in significantly faster and more effective biofilm removal. This process generates a large number of relatively small bubbles at a high rate. Due to their small size, these bubbles can detach the biofilm as a whole, rather than just locally, from the underlying surface. Consequently, the biofilm is preferentially removed as a whole or in relatively large, cohesive pieces, rather than in numerous smaller fragments, leading to a significantly improved cleaning effect.

[0056] Ammonium cations can also be used instead of metal cations. However, there is a risk that other ammonium compounds (e.g., ammonia) will be formed during the electrolytic process. This poses a risk to the patient and is also characterized by a very unpleasant taste and odor.

[0057] Experiments have shown that the biofilm detaches either in very small fragments or in larger, cohesive pieces. The latter is preferred, as it allows for comparatively large-area, very effective cleaning. Further investigations have demonstrated that the removal of the detached biofilm and / or its fragments is facilitated by foam formation on the implant surface. It has been found that, following the application of an electrolyte consisting of the described metal salts, acids, and water, which are primarily responsible for biofilm destruction and detachment, a second electrolyte is used that additionally generates foam in the cathode area.Such foam formation can be achieved by preferably adding to the electrolyte a substance that has at least three CH2 chain links or at least one CH2 chain link and at least one carbon ring compound. For example, oil and / or chlorhexidine can be used. In addition, ionic liquids can also be used, preferably containing an ionic liquid. - -, CI - - and / or OH - -ions. Since the organic cation fraction of an ionic liquid may be reduced and bleached on the implant surface, it is possible in a particularly advantageous design to attach bone growth factors to this cation fraction.

[0058] Mixing chlorides and iodides in the correct ratio prevents the formation of disruptive chlorine gas. The following is produced at the anode: 2J + 5Cl + 6H2O → 10HCl + 2HlO3

[0059] This means that hydrochloric acid and iodic acid are formed at the anode. These certainly have a strong antimicrobial effect and are neutralized again upon contact with the hydroxide that forms at the cathode.

[0060] A particularly preferred composition of the treatment fluid, which showed particularly favorable cleaning properties in laboratory tests, comprises an aqueous solution of sodium iodide (Nal) or potassium iodide (KI) in a mixing ratio of at least 5, preferably at least 10, particularly preferably at least 20 g of the salt per 30 ml of liquid (i.e. water, H2O, optionally enriched with CO2), reduced to a pH of about 2.7 to 2.9 by the addition of lactic acid.

[0061] During the process, a mean current density of at least 50 mA / cm² is required at post part 2 or at the component requiring treatment. 2 , preferably of at least 100 mA / cm 2, particularly preferably of at least 250 mA / cm 2 , provided that this current density refers to the outer surface of post part 2 (i.e., without considering surface-enhancing properties such as roughness or surface structure). An average current density of 50 mA / cm² has proven effective for biofilm removal. 2 up to 300 mA / cm 2 , preferably of 100 mA / cm 2 up to 200 mA / cm 2 This has proven to be particularly advantageous. For the removal of biofilm fragments, the average current density should preferably be in the range of 300 mA / cm². 2 up to 5,000 mA / cm 2 or particularly advantageous at 1,000 mA / cm 2 up to 2,000 mA / cm 2 will be increased.

[0062] The addition of H2O2 significantly reduces or eliminates the bubbling effect at the cathode. This results in a very strong H2O production, which can be used to rinse the surface.

[0063] For the targeted delivery of the treatment fluid to the area of ​​the room requiring treatment on post part 2, the treatment element 30 has a structural design as shown in the perspective view illustrations. Fig. 5 and in longitudinal section according to Fig. 6 is removable. The treatment element 30 is shown there in the state mounted on the post part 2. Also shown is a space 36 in the jawbone 38, which surrounds the post part 2 in a ring-like fashion in the area of ​​its external thread 6 and is affected by peri-implantitis and therefore contaminated with bacteria.

[0064] The treatment element 30 has a base body 40 designed essentially as a cylindrical shell, the end face 42 of which forms the contact surface 32 and is placed on the upper end face or edge 34 of the post part 2. For increased mechanical stability, a connecting pin 43 is also formed on the base body 40, the contour and geometric parameters of which are adapted to the receiving channel 12 in the post part 2 and which can be inserted into it.

[0065] Inside the base body 40, and coaxial with it, a central inner channel 44 is provided, in which a connecting screw 46 is guided. The connecting screw 46 engages with its screw thread 48 in the screw thread 20 provided within the post part 2. Unlike the connecting screw 18 provided for connecting the actual abutment 4 to the post part 2, the connecting screw 46 is not designed for high mechanical load capacity and longevity of the screw connection; rather, different design criteria apply to the connecting screw 46. In particular, the treatment process described below is taken into account, in which the connecting screw 46, and with it the post part 2, are to serve as an electrode for the current pulses. Accordingly, the connecting screw 46 is made of electrically conductive material, in particular a metal such as titanium.

[0066] The treatment element 30 is designed to supply the treatment fluid, which can also kill germs or bacteria, to the chamber 36. For this purpose, the base body 40 is provided with a number of media channels 50, which are connected at their inlet to a supply or feed system for the treatment fluid. In the exemplary embodiment, the media channels 50 are formed by grooves 54 cut into a ring body 52 surrounding the base body 40. The ring body 52 is pushed onto the base body 40, so that the grooves 54 are closed off on the inside by the outer shell of the base body 40, thus forming a channel system of the media channels 50. Alternatively, the media channels could, of course, also be integrated directly into the base body 40 in another way.

[0067] In the immediate vicinity of the contact area of ​​the end face 42 of the base body 40 with the end edge 34 of the post part 2, the channel system formed by the media channels 50 has a number of outlet openings 60, of which, for the sake of clarity, Fig.Figure 6 shows only two. In this embodiment, each media channel 50 is provided with an outlet opening 60. The cross-section and number of outlet openings 60 can be adapted to individual requirements. For example, a single outlet opening could be provided, forming a complete annular gap between the end face 42 and the end edge 34. Alternatively, multiple outlet openings 60 can be provided, arranged evenly around the circumference of the base body 40, particularly in the circumferential direction. The channel system formed by the media channels 50 opens with its outlet openings 60 directly adjacent to the end face 42 and thus directly above the space 36, so that the medium flowing out of the outlet openings 60 enters the space 36 below more or less directly.Through this design of the base body 40, the treatment element 30 thus forms a channel system with which the treatment fluid can be introduced directly and effectively into the area 36 requiring treatment.

[0068] In addition, the treatment element 30 is specifically designed as an electrical system. The design principle is, in particular, to enable pulsed application of current pulses to the medium, especially the treatment fluid, contained in the media channels 50. The treatment element 30 is designed to apply the current flow intended for cleaning the inserted implant part 2 in a targeted, localized manner within the treatment area 36. The treatment element 30 is designed according to the principle that the electric current can be supplied to the inserted implant part 2, which can then be used as an electrode.The treatment element 30 comprises a first conducting element 62, which forms an electrical current path and is electrically connected to the implant part 2 via the connecting screw 46, and which in turn can be connected to a suitably selected current or voltage source.

[0069] To form a counter pole or counter electrode, the electrical conductivity of the treatment fluid guided in the media channels 50 is utilized. For this purpose, the interior of the media channels 50 is itself electrically connected to the other pole of the current or voltage source. Thus, the outlet openings 60 of the media channels 50 form an electrical contact 64 or an electrical contact point through which the current flows into or from the implant part 2.By using the outlet openings 60, positioned in the immediate vicinity of the area 36 requiring treatment, as electrical contacts 64, the electric current applied for treatment and cleaning purposes can flow through the surface zone of the inserted implant part 2, which is infected with bacteria, and from there largely directly, i.e., in particular without "detours" via other body tissue or the like, to the contact surface 64 or to the contact point. In this exemplary embodiment, the media channels 50, including the electrically conductive treatment fluid contained therein and the corresponding connection elements, thus form a second conductor element 66, creating an electrical current path to the end-mounted contact 64.

[0070] Alternatively, the second conductor element 66 could also be designed as a "conventional" electrode, specifically as an electrically conductive, needle-like element made of metal. This element could be mounted on the base body 40, in particular so that it is slidably positioned in a longitudinal direction essentially parallel to the central axis of the base body 40. To form this electrode, or to provide an additional third electrode if required (which, for example, could be used to locally generate an electric field, such as for field amplification), a suitably shaped additional metal body 68 may be provided. The treatment element 30 can also be designed without the media channels, in which case the counter electrode, and thus the second current path, can be formed exclusively via the metal body 68. In this case, the contact 64 is formed via the end-free surface of the respective electrode body.

[0071] Furthermore, the positioning of the outlet openings 60 and / or the end contact surface 69 of the metal body 68 ensures that the contact surface 64 of the second conductor element 66 formed by them is positioned at a distance of at least 1 mm and at most 10 mm from the central longitudinal axis of the dental implant part 2 when viewed laterally.

[0072] The base body 40 of the treatment element 30 could be made of insulating material such as a ceramic or a plastic. In the exemplary embodiment, however, it is made of metal, namely titanium. To ensure reliable electrical insulation of the components from each other, its end face 42, which forms the contact surface with the dental implant part 2, is provided with an insulating coating 70 and is thus electrically insulated. Furthermore, the ring body 52 is made of insulating material such as a ceramic.

[0073] In an alternative embodiment, the treatment element 30' is shown in perspective view in Fig.Figure 7 shows a further channel system that can be used, for example, as a return channel for the treatment fluid, as a separate supply line for introducing a media mixture, or as a suction channel. In this embodiment, the ring body 52 is surrounded by a further ring body 71, into which grooves 74 are also provided on the inside to form further media channels 72.

[0074] In the embodiments described above, the media channels 50 and / or the conductor elements 60, 66 are designed in a substantially integrated manner and guided within the base body 40 or the ring bodies 52, 71 connected to it. Alternatively or additionally, some or all of the media channels 50 and / or the conductor elements 60, 66 can also be arranged externally on the base body 40 and connected to it via suitable retaining systems. This embodiment is shown in the perspective view in the exemplary embodiment according to Fig. 8 and in longitudinal section according to Fig. Figure 9 shows that, in addition to the components already described, the treatment element 30" shown there is provided with longitudinally displaceable channel elements 80 arranged on the outside of the ring body 52. ​​These can be designed analogously to the media channels 50 in the form of cannulas or the like and be supplied with the treatment fluid, and can also serve as conductor elements 66. Alternatively, they can also be made of metal in the form of electrodes and be electrically connected to the current or voltage source. In addition, in the exemplary embodiment according to Figure 9, the treatment element 80 is provided with longitudinally displaceable channel elements 80. Fig. Figure 8 shows another variant in which, in addition to the media channels formed by the externally arranged channel elements 80, integrated media channels 50 formed by grooves 54 in the ring body 52 are also provided.

[0075] The treatment element 30, 30', 30" is preferably used in a treatment system 90, as described in Fig. Figure 10 shows that the treatment system 90 is designed for an inserted dental implant component or post component 2 and comprises the treatment element 30, 30', 30" and, in addition, a connecting element 92 between this and a hose assembly 94, a plug connection 96 between this and a supply and control unit 98 located outside the patient's mouth. This supply and control unit 98 includes an electrical supply which can apply a voltage and / or allow a current to flow between the electrode in the post component 2 and another electrode which may be located in the treatment element 30, 30', 30", the plug connections 96, the hose assembly 94 and / or the supply and control unit 98.

[0076] This voltage or current can be applied to the two electrodes as a direct current (DC) with polarity in either direction or as an alternating current (AC). If it is an AC voltage, it can be a sine wave, triangle wave, square wave, or any conceivable superposition of these with different frequencies. Furthermore, this AC voltage can be superimposed on a DC voltage. It is also possible to use a pulsating DC voltage. To generate an electric field, a third, electrically insulated electrode can preferably be installed in the treatment element 30, 30', 30".

[0077] As described above, it is particularly advantageous to apply several electrolytes with different compositions to or onto the implant, either sequentially or simultaneously. The treatment system 90 is designed for this purpose. In particular, the supply and control unit 98 includes reservoirs for at least two liquids or electrolytes. These can be pumped simultaneously (mixing) or sequentially via the hose assembly 94 into the treatment element 30, 30', 30" via one or more valves or valve units. In a particularly advantageous configuration, the supply and control unit 98 also includes a suction system to remove the liquids or electrolytes supplied via the treatment element 30, 30', 30" after use. In a particularly advantageous configuration, the supply and control unit 98 also includes a CO2 purification system for water or other liquids / electrolytes.For process optimization, media temperature control can also be integrated into the supply and control unit 98.

[0078] The hose assembly 94 and the connectors 96 are designed to ensure the flow of electricity and media. In a complete configuration, this would include, in particular, three electrical conductors and two fluid / electrolyte conductors.

[0079] The electrode material can be the same material as the post part 2. Since the post parts 2 are preferably made of titanium or a titanium alloy, it is preferable to make the additional electrode(s) from a different metal. Titanium and titanium-like metals usually form a protective oxide layer when subjected to anodic current, which acts as an insulator. To avoid restricting the current flow via such an oxide layer when the post part 2 is subjected to cathodic current, it is advantageous to use a metal that does not form an oxide layer or forms only a minimal one as the counter electrode. In a particularly favorable case, this electrode does not corrode upon contact with the media / electrolytes or when subjected to a voltage or current. Preferably, this electrode is made of gold, platinum, or palladium.

[0080] Should the interior of the inserted implant / post part 2 also be contaminated and therefore require cleaning, it is possible to rinse the interior separately or together with the medium and apply an electric current.

[0081] The conductor elements can also be designed in the form of a flexible or rigid membrane that does not allow liquids to pass through, but only ions present in the electrolyte. In such a configuration, one of the current paths preferably terminates inside the post part 2 and continues past the contact surfaces 32, which in this case do not seal at all or only partially, to the outer surface of the post part 2. Reference symbol list 1 Dental implant system 2 first implant part / post part 4 second implant part 6 external threads 8 apical end 10 connecting pins 12 recording channels 14 Indexing element 16 End channel piece 18 Connecting screw 20 screw threads 30, 30', 30" Treatment element / treatment abutment 32 contact area 34 Front edge 36 Room area 40 basic shapes 42 Front surface 43 connecting pins 44 Guide sleeve 45 spacers 46 Connecting screw 48 screw threads 50 Channel / Media Channel 52 ring bodies 60 Outlet opening 62 Conductor element 64 Contact 66 Ladder element 68 metal bodies 69 contact area 70 insulating coating 71 Ring bodies 72 Media Channel 74 Nut 90 Treatment System 92 Connecting element 94 Hose package 96, 98 Supply and control unit

Claims

[1] Use of an aqueous solution of an acid containing a metal salt such that a conductivity of at least 30 mS / cm is obtained, as a treatment fluid for cleaning bacterially contaminated surfaces of bone implants or dental implants. [2] Use according to claim 1, wherein the aqueous solution has a conductivity of at least 75 mS / cm and preferably at least 150 mS / cm. [3] Use according to claim 1 or 2, wherein the metal salt is a salt of aluminium, an alkali or alkaline earth metal. [4] Use according to claim 1 or 2, wherein the metal salt is a potassium, sodium, calcium, magnesium or aluminium salt. [5] Use according to any one of claims 1 to 4, wherein chlorine or iodine is provided as the salt former for the metal salt. [6] Use according to any one of claims 1 to 5, wherein the aqueous solution of an acid is an aqueous solution of an organic acid [7] Use according to claim 6, wherein the acid is an α-hydroxylcarboxylic acid, preferably lactic acid, citric acid, acetic acid or malic acid, or a combination of these ingredients. [8] Use according to any one of claims 1 to 7, wherein the treatment liquid has a pH value of less than 5, preferably less than 4, particularly preferably 2.7 to 2.

9. [9] Use according to any one of claims 1 to 8 for the removal of biofilm from a bone or dental implant.

Images