DE8904429U1 - Device for applying a metallic substance to teeth or foreign materials on the teeth - Google Patents

Description

Description

Device for applying a metallic substance to teeth and foreign materials located on the teeth.

Device, procedure, application and pretreatment measures.

The invention relates to a device according to the preamble of claim 1.

In dentistry, a carious defect in a tooth is treated with a filling in order to counteract the progression of carious destruction. The most commonly used filling materials for fillings that are to be processed plastically are the most frequently used amalgams, which are particularly indicated in the posterior tooth area (in the non-visible area), and the other is mallet gold and plastic. In addition to glass ceramic, porcelain and plastic fillings, single or overlay fillings are mainly represented as metal cast fillings. The NON-GAMMA-2 amalgams that have been used more recently are placed in the cavity in a plastic state, condensed and then carved. In order to achieve a good marginal seal, a seamless transition from the filling surface to the enamel surface and better surface properties, the filling edge is finished after the amalgam has hardened and the entire filling surface is then polished.

The more expensive inlays or onlays based on metal casting have the advantage over amalgam fillings of higher fracture and pressure resistance, better surface properties and better workability in particularly difficult to access areas (proximal surfaces/filling edge located under the gum line). After such a casting filling has been made and cemented, the filling is also removed for the reasons mentioned above.

the patient's mouth. J If a tooth is severely damaged, the

' ultimately its crowning. The crown edge is located

either partially (3/4 crown) or completely below the gum line (subgingival).

In addition to the measures listed above to achieve an improved marginal seal and seamless transition from the filling surface to the enamel surface, the cements used to insert the inlay or overlay fillings and crowns are chosen to be as thin as possible in order to reduce the cement joint and thus improve the marginal seal. As mentioned in the introduction, the aim of dental filling therapy is to stop the further decay of a tooth due to caries. However, this can only be achieved if the filling itself has not created new predilection points for the caries destruction process. The locus minoris resistentiae on a tooth that has been treated with a filling is always the filling edge, i.e. the borderline between the filling material and healthy tooth hard substance (enamel/cementum), particularly in places that are not or only difficult to access for natural and active tooth cleaning (approximal surfaces or distal surfaces of terminal teeth/subgingival surfaces). If a new carious lesion, so-called secondary caries, occurs in such a place, then this is particularly dangerous due to the path paved by the preparation and the direct proximity to the pulp. In order to reduce the risk of secondary caries, in addition to the measures listed above, the edges of a filling are, if possible, moved to areas that are easier to access for tooth cleaning ("Extention for prevention" [BLACK]).

However, a filling that has been processed according to the measures listed here, lege artis, still has a recovered i| susceptibility to secondary caries. This applies to both

the plastic fillings to be processed (amalgam, veneers,

gold, plastic, cements, etc.) as well as the inlay or overlay fillings and crowns. From an ultrastructural point of view, at the latest after a certain period of wear, there are always retention points for the carious microorganisms at the edge of the filling.

In the case of amalgam fillings, which are placed on '

their edges must not be thinly tapered, the transition from the cavity wall

or floor to the tooth surface in the right or blunt position.

angle. Neither enamel, dentin nor cement can be treated with Tj

Amalgam forms a chemical bond, so that forces acting on the filling can easily cause a gap to form or widen (e.g. due to chewing forces / temperature fluctuations with different thermal expansion coefficients of the tooth hard substance and the filling material). i The acid produced by the microorganisms then inevitably leads to demineralization and subsequent carious lesions of the enamel edge adjacent to the amalgam. After the loss of this tooth hard substance, an enlarged retention area for the cariogenic plaque is created (circulus vitiosus). In addition, the enlargement of the gap at the edge of the filling causes a tumbling effect known as percolation j

aiii , dürCii the saliva together with ri i k &Ggr;&Ogr;&Ogr; rgön 15&idigr;&idigr;&bgr;&idigr;&idiagr;1&Pgr; "

ka'-n enter this space.

In the case of inlay or overlay fillings and crowns, this problem is partly solved in that the filling edges can be made thin. In addition, certain types of cement allow a chemical bond to the tooth surface.

hard substance. Nevertheless, the filling edge, 3

ie the cement joint is the point of attack for the cariogenic S

Microorganisms. At the latest after a certain period of wear, the cement is washed out or dissolved, leading to the formation of a retention area, which means that the conditions §

conditions for secondary caries are created. 1

Today's composite plastic fillings, which however ~i

only in the front teeth area or in areas with little or no load

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In principle, fillings that are indicated for the most difficult areas show the best filling margin design. Here, the filling material merges into the enamel without an intermediate layer, tapering thinly. This is made possible by the elasticity of the plastic and the high bond strength between enamel and plastic. The latter is due to the chemical bond and the micro-retentive relief created by acid etching with the resulting increase in surface area. However, a prerequisite for such a filling is that the prepared cavity is surrounded exclusively by still healthy enamel substance. This is because only the enamel is able to form a chemical bond with the plastic. The main disadvantage of composite fillings is the polymerization shrinkage (linear setting contraction PMMA = 1.5-2.8%; composite = 0.4-0.9 %) and the high thermal expansion coefficients (CTE: PMMA = 80-120 ppm/°C j composite = 20-50 ppm/°C) compared to the hard tooth substances (CTE = 10 ppm/°C). The setting shrinkage leads to more or less strong tensions at the cavity edge, which cannot be avoided even with the sandwich technique. In the case of a temperature drop caused by food intake (ice-

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The tensions are to be attributed to the former, so that gaps at the filling edge can quickly develop or enlarge, with the consequences that this entails. Furthermore, the disadvantageous properties of swelling, discoloration and tissue irritation must be taken into account with plastics. Just as important as the risk of secondary caries are the harmful effects on the periodontium of a tooth with a filling or crown caused by chemical or mechanical irritation. This applies to fillings and crowns whose filling or crown edge is at least partially subgingival. The mechanical stimuli are caused, for example, by protruding crown edges, inadequate polishing, etc., i.e. mainly by

It is important to distinguish between irritating teeth caused by inaccurate processing, from primary chemical irritants caused by the filling material, and from secondary chemical irritants caused by bacterial products (acids, endotoxins). The latter usually occurs with subgingivally localized secondary caries, as both diseases have the same origins.

Thus, in addition to preventing secondary caries, the prevention of periodontal damage when filling or crowning a tooth has not yet been adequately solved.

The solution to this problem lies in a new therapeutic procedure in which a tooth to be treated with a filling or crown is provided with a firmly adhering, liquid-tight metal coating up to or slightly beyond the preparation border after conventional preparation and, if necessary, after placing or inserting the filling or crown, the filling or crown edge is sealed or leveled with metal. The applied metal must have a smooth surface.

A device for applying metal to teeth does not yet exist. Numerous devices for applying metal to non-conductive materials are known from plastic electroplating and mirror manufacturing (reduction deposition, silver spraying, vacuum vapor deposition, conductive varnish application, etc.). However, these and the previous devices for applying metallic substances do not allow the application to teeth or foreign materials on teeth in the patient's mouth, even if they were manufactured in miniature. It is necessary to create a device that meets the special requirements of a dental instrument.

speaks.

The invention is based on the object of providing a dental tool that is easy to manufacture and easy to handle.

f ^; create a device that allows metal to be deposited in the patient’s mouth

Teeth or foreign materials on the teeth can be firmly adhered to.

&igr; This task is carried out in a generic facility

e: by the characterizing features of claim 1.

The invention avoids the disadvantages of the prior art.

The device according to claim 1 enables the application of firmly adhering metal deposits on teeth or on these.

■;'· foreign materials found in the patient's mouth. The

The metal coating is applied by separating metal from its solution. Depending on the needs and requirements, you can choose between several types of separation.

external power source is based on the redox reaction of the deposited metal cation and a reducing agent to the deposited, elemental metal and the oxidized reducing agent remaining in solution. Two deposition modes can be distinguished here. In the <-;..■ second electroless deposition type, the reaction takes place immediately or, if necessary, with a delay after the metal cation and reducing agent solution are brought together due to the sufficiently large effective redox potential [see claim 7j. The second electroless deposition type requires a catalytically active metal surface or metal chain due to a correspondingly small effective redox potential, through which the redox reaction first begins.

is possible [see claim 8].

The deposition mode of the former type can in turn be differentiated according to different types of application of the liquids and agents.

The application of the solutions in the spray process [see claim 10;16] corresponds to the principle of the silver spray process for chemical mirroring (mirror production) or for the deposition of a conductive metal layer on the surface of a non-conductor (pretreatment of ABS plastics for galvanic metal deposition). The individual solutions are separated, atomized by means of compressed air and sprayed in the mold onto the object surface, since they meet on or immediately in front of it, 'j

i.e. both solutions mix with each other. The solutions are adjusted so that the redox reaction is reversed.

takes place after mixing. |

In the spraying process [see claim 9;16] the solutions are sprayed without atomization in the form of liquid jets

(liquid columns) which are also located on or directly |

bar in front of the object surface. At $

Another way of applying the solutions to the object surface is to apply the solutions separately to the tooth. ;,]

and brought together in a chamber [see claim 17] or a vessel [see claim 26], each of which is delimited by the object surface. Here, the solutions mix and thus separate. j

Instead of a molecularly dispersed reducing agent I

[see claim 4], in the application methods listed up to this point, the solution used can also be a liquid with metal dissolved in colloidal dispersion or finely distributed as a powder [see claim 5;6]. The metal has a correspondingly negative standard potential in order to be able to act as a reducing agent. Depending on '

the particle size, the still elemental metal is included in the metal separating from the solution

instead of.

A modification of the spraying process is the supply of the reducing agent by means of a compressed gas jet as a carrier [see claim H]. In this process, the reducing agent can be a gas [see claim 12] or a solid [see claim 13]. The compressed gas jet serves on the one hand to atomize the liquid jet containing the metal salt solution and on the other hand as a carrier for the reducing agent. The term compressed gas is intended to draw attention to the fact that possible reactions between compressed air and substances can be prevented, for example, by using nitrogen gas.

The advantage of this deposition mode lies in the high deposition or application speed of the metal onto the object surface (2 - 4 μα in seconds). [Lit.: Practical Galvanotechnology, EGLeuze Verlag 1970 page 371]

The second deposition mode of electroless deposition corresponds from a functional point of view to the process of reduction deposition (conductive metal deposition). The liquid containing the reducing agent and the metal to be deposited in solution is brought into contact with the object surface in this deposition mode.

Deposition only takes place in the presence of a catalyst. The metallic or nucleated object surface represents such a catalyst.

In contrast to the unstable solutions, the deposition from the stable solutions is only influenced to a relatively small extent by the type of application. The decisive factor, however, is the constancy of the substance concentrations. In technology, this is ensured by a sufficiently large bath volume in which the object to be coated is located. In the mouth of the patient, such a procedure is

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However, this is not possible. The constancy of the substance concentrations is achieved by means of the flow of the solution, i.e. in dynamic equilibrium (steady state). Before there is a noticeable decrease in the concentrations in the solution that is brought to the surface of the object, it is already transported away again [see claim 18;21;27;]. The same applies to the subsequently mentioned deposition with an external power source [see claim 19;20;22;23;28;29;].

Due to the requirement that the contact surface must be sensitized and activated or metallic, the application of the metal to the surface of the pretreatment is always localized.

The advantage of this deposition mode lies not only in the localized deposition but also in the uniform deposition in terms of quality and quantity of the deposited metal. The big disadvantage is the low deposition speed.

In the electroless deposition methods listed up to this point, the deposition process and quality of the metallic deposit can be influenced by the choice of metals to be deposited, reducing agents, solvents, additives, setting of the concentrations, pH value, temperature, etc., and especially in the case of spraying processes, by varying the liquid transport rates, their relationship to one another and the degree of atomization of the spray jets.

Furthermore, the metals to be deposited can also be used in low-valence cation form or in colloidal disperse solution, provided that they can be stabilized according to the application.

The deposition of a metallic deposit using an external power source is also based on a redox reaction, but it takes place in the form of two partial reactions at different locations. On the cathode surface, which is the

to be coated, the reduction of the metal cations in solution to the elemental metal takes place by absorbing electrons from the external power source. At the same time, a reducing agent [see claim 19; 22; 28] or the anode material [see claim 20; 23; 29] is oxidized at the anode by releasing electrons to the external power source. The solution between the anode and cathode thus closes the circuit of the external power source as a second type of conductor. Even with deposition using an external power source, several types of deposition are possible, which differ primarily in the anode partial reaction. The anode reaction of the galvanic deposition represents the electrolytic dissolution of the anode metal as a result of oxidation to the metal cations. The crucial point in electroplating technology, namely that the electrolytic dissolution of the anode material ensures that the metal ion concentration remains constant, plays a subordinate role here. Even metals that cannot be deposited can be used as anode material. However, this requires the flow of the solution mentioned above to ensure its removal.

'.', For other deposition methods with external power source

are at the anode, the reducing agents in solution

f- medium is oxidized with the release of electrons to the power source. The anode material is an inert metal. The choice of substances, concentrations, redox potentials, current strength, liquid transport rates, etc. must be coordinated.

Localized deposition is guaranteed on the one hand by the requirement of the conductivity of the object surface, as well as its cathodic connection, and on the other hand is made possible in relative terms with regard to the deposition speed by the locally different sizes of the electric field. The

The desired spatial extent of the electric field is achieved by means of the anode design, which can in principle be chosen arbitrarily.

The advantage of these types of deposition, in addition to the localized deposition, is in particular the uniform deposition in terms of quality and quantity of the deposited metal. As with reduction deposition, the major disadvantage is the low deposition speed.

Compared to reduction deposition, the equipment required is a disadvantage. On the other hand, it is possible to use an external power source to deposit metals that could only be deposited under difficult or dangerous conditions without an external power source (e.g. electroless deposition of chromium). The quality of the deposited metals must also be taken into account in this context.

In order to be able to use a device according to claim 1 clinically, it must not only be able to apply metal firmly to the tooth, but also meet the various types of application, such as applying the metal to the preparation surface, to the filling edge gap or to the metal surface for surface finishing. Such a task cannot be fulfilled with a single device.

The requirements are met by a device which is constructed from several embodiments of the device according to claim 1.

It can be divided into a stationary device box, a mobile handpiece with the treatment attachment and the supply hose that connects the two.

From a functional point of view, it is made up of several devices that are characterized by the method of application and the type of separation. One or more elements of a device can also be part of

represent more devices.

Such a functional apparatus generally consists of a storage container (1) with the device for pressurizing [see claim 32] and the solution (2) contained therein, a feed tube ( 3 ₎ connected to its lumen and the _treatment unit constructed from the treatment shaft (4) and functional head (5) .

At least one storage container with a pressure generating device and supply pipe must be assigned to a solution of a functional device. The solution or solutions are transferred from their storage containers to the treatment shaft via their supply pipes by means of pressure and exit from the functional head according to their application and type of separation. However, substances can also be fed to the functional end in other ways, such as by means of compressed gas or compressed air.

The functional equipment of a device differs according to their method of application and type of application and deposition , mainly in their treatment attachments, the quality and quantity of the solutions to be supplied and additional supply lines (e.g. compressed air; electrical lines).

Each functional apparatus represents an embodiment of the device according to the invention as defined in claim 1. These are explained in more detail below.

One embodiment of the device according to the invention consists in that the application device consists of a spraying device, has at least two storage containers with the associated liquid-carrying pipes (6), which end separately in the functional head (7) of the spraying device, in at least one storage container the metal-containing liquid and in at least one other storage container

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ter the liquid containing the agent for depositing the metal is contained.

In this embodiment (see Figure 2), the solutions emerge from the functional head in the form of two liquid jets (8) which meet on or immediately in front of the object surface (9). The mixture of the solutions preferably represents an unstable solution [see claim 7]. The deposition of the metal from the solution occurs immediately after mixing. In order to obtain good quality and high adhesive strength of the metallic deposit on the tooth hard substance (enamel) or on the foreign materials (plastics/metals), it is necessary that the redox reaction takes place in the immediate vicinity of the surface-limiting structure. It is therefore important to coordinate the substances used, their concentrations, liquid transport rates of the spray jets, both absolute and relative to one another, diameter and impact speed of the liquid jets, to name just the most important. For example, it must be considered that as the jet diameter increases, the effective mixing of the solutions is reduced, and that too low an impact speed of the liquids can lead to a reduction in the mixing speed of the liquids. The location of the redox reaction shifts. The solvents and substances used should also be as pure as possible (use of deionized water). All of these factors can lead to poor quality and poor adhesion of the metal to the object. From the above it is clear that it is extremely important for the operator to maintain the working distance (10) - this is the distance of the functional head from the object, which is identical to the distance of the meeting point of the liquid jets from the functional head.

To make it easier for the practitioner to maintain the working distance, the functional head is provided with at least two light sources (11) with beam paths that are as parallel as possible, the beams (12) of which are at the same distance

from the functional head like the liquid jets
[see claim 15]. The practitioner is now able to indirectly perceive the working distance optically.

f both light rays have the same color, the operator recognizes

^: . handler the correct working distance once by

there is only one point (13) on the tooth, and secondly by the intensity maximum. If the distance is too great, he observes when moving the functional head to

the Ohipkt &Lgr; a &agr; 7 ti &agr; amines rii r V on Aar l.irlitniinlitp. 1st slp zn j _____-._. - . _ ..__ &mdash;&mdash;-...j. ,

small, he observes the light points moving apart as he approaches them. If the two light sources are of different colors, recognition can also be made by the color change at the correct distance and the change in position.
of the different colored light points when the distance is too large or too small.

^: Furthermore, it is advantageous to direct the liquid jets

■ to meet at an acute angle (14).

Because as this angle becomes smaller, the changes at the meeting point (12) of the liquid jets at
This is shown in Figure 2 by comparing the working distance
of routes 16 and 17.

In general, the liquid jets should have a small diameter and a high impact speed. The liquid escaping from the function head
is removed by means of a suction device [see claim 33]. The suction force should be as large as possible
without affecting the path of the liquid jets. For the spraying and atomizing processes

" the suction device corresponds to the one used in dentistry

used "large" saliva ejectors. Since, despite the use of an excess of reducing agent in unstable solutions, the deposition never takes place completely on the object surface, but partly in the solution, it is advisable to collect the used solutions for reprocessing.

This design has, in addition to the generally high de- J Divorce speed, compared to the subsequent I

The sprayers described above have the advantage of relatively localized and rapid deposition.

It is primarily used in the subsequent gross local §

ized application of the metal, e.g. at § the preparation border of the tooth stump previously coated with a metal coating, in order to determine the layer thickness of the

upper section, or to easily reach the, e.g. in

to close and level the occlusal cement joint |j

nen. |

One embodiment of the device according to the invention consists in that the application device consists of a (in the sense of atomization) operated with compressed gas (compressed air) (18)

Sprayer consists of at least two storage containers with 1

the associated liquid-conducting pipes (19) which end separately in the functional head (20) of the spray device, at least one storage container contains the metal-containing liquid and at least one other storage container contains the liquid with the agent for separating the metal.

What was mentioned in the previous explanation of the embodiment regarding the type of deposition, influences on the quality and adhesive strength of the metal coatings, as well as what was mentioned with regard to claims 7, 15 and 33 also applies to this embodiment.

The main difference to the above embodiment is that each of the liquid jets emerging from the functional head is atomized by means of compressed gas or compressed air.

The atomization enables an improved mixing of the solutions on the object surface and the increased progress of the redox reaction near the surface-limiting structure (see above). The improved mixing of the metal salt-containing

The effectiveness of the solution and the solutions containing the reducing agent is based on the penetrability of the two spray mists (21). The fine droplets of both solutions are evenly distributed over the object surface shortly before they hit the surface, and when they hit the surface the droplets mix. Due to their small volumes and the resulting short diffusion distances, the substances are immediately evenly distributed in the solution. This is the basis for the simultaneous and consistent course of the sulfuric acid reaction and thus for the good quality and adhesion of the metal coatings.

A further effect of atomization is the high acceleration of the droplets and the associated increased impact speed.

From the above it is clear that the aim of atomization is, on the one hand, to obtain the smallest possible average droplet diameter with a small scattering range - i.e. all droplets with the same diameter if possible - and, on the other hand, to obtain the highest possible droplet velocity.

Small and evenly distributed diameters of the droplets can also be achieved using ultrasound [see claim 14]. The ultrasound source should be located on the handpiece and, for example, cause the tube ending in the function head from which the liquid emerges to vibrate. In order to achieve a high impact speed, the liquid jet must emerge from the tube at a high speed. This is achieved by a correspondingly small inner tube diameter and the high pressure in the storage container [see claim 15: device according to claim 9].

Another possibility is the combination of ultrasound for atomization and compressed air only for acceleration of the droplets [see claim 15 device according to claims 10 to 14]. The advantage of using ultrasound is, in addition to the aforementioned

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in the simple design of the function head. It is used primarily for very small versions of the function heads of the spray process. In combination with compressed air, ultrasonic atomization is used in particular for the surface application of metal. In order to avoid spot application and the associated varying thickness of the metal coating, the liquids are sprayed in such a way that the impact surface has an oval shape with the largest possible water-to-water ratio (t22), i.e. is as narrow and long as possible. This enables the operator to provide the object surface with an evenly thick coating in just a few strokes. A different type _{of atomization} using compressed air than that outlined in Figures 2 to 5 is obtained if the air and liquid are brought together early in the pipe. Its advantage is that it is easy to manufacture, particularly with small dimensions. However, atomization is less effective. With regard to the suction device, the suction power of the spray devices must be reduced compared to the spraying method or must be extracted from a greater distance in order not to deform the spray mist. The advantage of this design is the high deposition speed and the ability to be applied to relatively large areas. It is primarily used for the surface application of the metal directly to the post-preparation pre-treated tooth.

The second area of application of this spray device with a correspondingly smaller and differently shaped functional head is the subsequent application of the metal, especially on hard-to-reach areas, such as approximal surfaces located apical to the preparation border. One embodiment of the device according to the invention consists in the application device consisting of a spray device operated with compressed gas (compressed air) (in the sense of atomization), at least one storage container with the

associated liquid-carrying pipe which ends in the functional head of the spray device, at least one storage container contains the liquid containing the metal and the compressed gas contains the agent for separating the metal.

This embodiment differs from the one mentioned above only in the way the reducing agent is added (see also the discussion of the types of deposition). If the reducing agent is present as a gas, it must be distributed quickly in the emerging liquid during atomization. This is achieved by a correspondingly fine atomization and thus small diffusion distances or large attack surface.

If the reducing agent is in the form of a metallic powder, particles with small average diameters are preferably used, because even distribution of powder and metal salt solution plays an important role in the deposition. In terms of the deposition reaction, this spray device is similar to the embodiments of the devices according to claims 5 and 6. Here, the metal particles are distributed throughout the solution. The advantage of all these embodiments lies in the increased application speed of the metals. Depending on the particle size, the inclusion of the still unused metal takes place in the metal deposited from the solution. It should be remembered that when the metal-containing solution is mixed with the metal acting as a reducing agent, the contact deposition of the metal in the solution immediately takes place on the particle surface. In places where the metal has deposited on the particle surface, deposition no longer takes place. Furthermore, the area of attack of the reducing agent decreases significantly. It is therefore important in this case too to maintain an even distribution of the components. Another requirement is the contact of the metal particles

angle with the metallic object surface in order to
to ensure alloying of the metals. If this contact is not present, the deposition of the metal
exclusively on the surface of the particles.
This contact is achieved by the high acceleration of the particles. The high density of the metal particles proves to be an advantage here.

The metal powder in the solution can be separated by means of e.g.
The agitator in the storage tank ensures that the metal particles are evenly distributed in the solution before and during treatment. Instead of an agitator, the metal particles are distributed with air streams during feeding using compressed air.
These embodiments are particularly suitable for applying intermediate layers of metal. The application
The metal is thus applied to the metallic surface and is subsequently coated with another metal layer to prevent the formation of local elements.
One embodiment of the device according to the invention consists in that the devices mentioned up to this point have a functional head with a support cushion (23) which locally limits the application by means of its support.

This embodiment serves to close and level a surface irregularity, i.e. the cement joint or the filling edge gap (2^). The advantage over the other embodiments of localized meta 11 application lies in its high speed.
The cushion is discussed further below.

One embodiment of the device according to the invention consists in that the application device comprises a functional head with a support pad, at least two storage containers with
at least one liquid-carrying pipe each ending in the functional head, at least one storage container contains the liquid containing the metal and at least one other storage container contains the liquid with the means for separating the metal, the

Liquids from their storage containers are transported separately via their pipes to the functional end, the functional end forms a channel by means of its support surface and the object surface provided with a surface irregularity, the liquids are brought together in the functional end and the liquid mixture is passed through this channel.
This design corresponds to the above

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the solutions emerging from the function head are immediately mixed and immediately directed along the object surface in a localized manner. Their advantage over the previously mentioned corresponding design in the spraying and squirting process lies in the small size of the function head and in the high application speed compared to the devices for localized application that are yet to be mentioned. The disadvantage, however, is the low metal yield from the solution.

One embodiment of the device according to the invention consists in the application device having a matrix-like device which transfers the prepared tooth into a vessel containing the same, the functional head, at least two storage containers, each with at least one liquid-carrying pipe ending in the functional head, a suction device with at least one pipe ending in the functional head, at least one storage container containing the liquid containing the metal, at least one other storage container containing the liquid with the means for separating the metal, the liquid from the storage container passing through the functional head into the vessel containing the tooth, and at another point the liquid is removed from the vessel using the suction pipe.

In terms of deposition, this design corresponds to the previously mentioned device. The difference lies in the application. It is used for the flat application of metal

on the prepared and pretreated tooth. The description of the additives can be found below.

One embodiment of the device according to the invention consists in the application device having a functional head with a support pad (25), at least one storage container with a liquid-conducting tube ending in the functional head, the storage container containing at least the liquid with the metal and the means for depositing this metal, the liquid from the storage container reaches the functional end via the tube, the functional end forms a channel (27) by means of its support surface and the object surface provided with a surface irregularity, and the liquid is guided through this channel (28).

In this embodiment, the metal is applied from stable solutions using the reduction deposition method (see also deposition types).

One embodiment of the device according to the invention consists in that the aforementioned device has an external power source (30), the anode (31) of which in the function head is in direct connection with the liquid (33) in the function head and the cathode of which has an electrical contact with the metallic object surface. In this embodiment, the metal is applied from stable solutions in the manner of deposition with an external power source, the anode being an inert metal and the reducing agent being oxidized on it (see also types of deposition).

One embodiment of the device according to the invention consists in the application device having a functional head with a support pad, at least one reservoir with a liquid-carrying tube ending in the functional head, an external power source, the reservoir contains at least the liquid containing metal, the liquid from the reservoir reaches the functional end via the tube, the functional end is closed by means of

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its support surface and the object surface with a surface irregularity form a channel, the liquid is guided through this channel, the anode of the external power source in the function head is in direct contact with the liquid and the cathode has an electrical contact with the metallic object surface.

In this embodiment, the metal is deposited from stable solutions using a deposition method with a small current source, whereby the anode represents the metal that dissolves through oxidation (see also deposition methods).

The last three embodiments mentioned serve for the localized application of the metal, preferably in surface depressions, and thus enable the sealing or leveling of the cement joint or the filling margin (24) of the tooth provided with the crown or filling. They are characterized by their functional head, which will now be described in more detail (see Figures 6 to 9).

This functional head consists of at least the frame (34), the supply pipes (35) and the support cushion (25/23). The frame consists of a solid, non-flexible material and is firmly anchored to the supply pipes. It is connected to the support cushion on its underside. Behind the distal edge of the support cushion is the search pin (1*) which lies above the support plane during the work process and only enables the "blind" search for the surface depression by bending the functional end. The support cushion is an elastic and, if possible, non-abrasive material with preferably hydrophobic properties (e.g. silicone mass). In top view (Figures 7E and 8) the support surface of the cushion resembles a rounded "A" (3 ⁷ }. The crossbar (38) creates two spaces, the front (39) and the rear chamber (40). The support

part of the cushion, especially the d

outer arch of the "A" is during the work process !§

the surface of the tooth with a sufficient pressure to ensure the fluid impermeability between the support cushion and the tooth surface. From the supply S

The solutions enter the front chamber and 1

flow at least for the most part through the, with the help of ■;

the support surface formed channel (27) into the rear

Chamber. This means that the solutions in the process &Igr;&ogr;- ;.&idiagr;.

calibrated along the surface to be coated;

leads or is kept present, where it finally leads to the ab- _; ', ^:

divorce comes. ra

For deposition with an external power source, the object surface is to be provided with the cathode (33) and the functional end additionally with the anode (31) [see claim ^i 19;20]. It is advantageous to arrange the anode directly above the surface depression, i.e. the anode represents a part of the luminal boundary of the channel (see 7C). This is because the electric field promotes deposition particularly in the depression.

For deposition without an external power source according to the reduction process: the solution passes through the

the channel into the rear chamber [see claim 18]. When separating with unstable solutions, the solutions are

gen are first brought together in the front chamber and then passed through the channel [see claim 17].

Due to the small cross-sectional area of the channel and the .

The resulting high resistance would require the solutions ^

with a relatively high pressure in the anterior chamber j

or through the channel. The high pressures cause ''

in turn required an increased contact force of the functional end on the tooth in order to maintain fluid impermeability. In addition, there would be strong turbulence in the front chamber, which would have a negative effect on the precipitation separation. It is therefore advantageous to equip the rear chamber with a suction device

HII II

[see claim 33]. The solutions passing through the channel are led into a collecting container via the suction pipe (41). The precipitate in solution can be filtered off, the filtrate can be reused in some cases, or collected for reprocessing. During the working process, unnecessary leakage of the solutions into the working area and contact with the anatomical structures can also be avoided.

In order to further prevent the leakage of liquids in the front ram through the unintentional gap between the cement joint and the front part of the support cushion, i.e. at the tip of the "A", the cushion can be designed to extend slightly beyond the support plane at this point. This elevation can also be used as a second locating pin (see 7C).

At this point, the functional head of the above-mentioned device for localized application using a spraying or atomizing method will now be described [see claim 16] (Figures 4 and 5). Here, the solutions are atomized using compressed air and sprayed into the surface depression. However, it must be taken into account that the suction device must have a sufficiently large capacity to be able to effectively suck out the greatly increased transport volume (solutions + air). This is because if there is an increase in pressure in the front chamber due to a build-up of liquid and air, the spraying effect is prevented. In addition to the increased suction capacity, this measure can be supported by reducing the total channel resistance. This is partly achieved by the crossbar of the "A" no longer being in contact with the tooth surface. Figures 4 and 5 show two functional heads of such a device. The functional head in Figure 4 is used for spray separation into the approximal filling edge gap, and the one in Figure 5 into the vestibular or oral filling edge gap. (See also Figure 9)

·

The biggest problem with the deposition of the metallic deposit, for example in the cement joint of a tooth fitted with an inlay, is the part of the cement joint located in the approximal space. The treatment attachment or its functional head intended for this purpose is kept so small in its dimensions that at least half of it can be brought into the approximal space of the tooth to be treated (the size of a needle eye) . * Thus, the deposition in the cement joint in the area of the iris dental cavity takes place in two steps, namely once from the buccal side and once from the oral side. Up to this point, only the functional end for the deposition in the cement joint in the area of the approximal space has been dealt with. The corresponding functional end for the deposition in the buccal and oral areas is outlined for this type of deposition in Figures 6 to 8. It only differs in its morphological arrangement from the functional end described above (see also Figure 9).

All three of the above-mentioned designs enable localized metal deposition in the corresponding surface depression with such a functional end. The advantages and disadvantages of the individual devices can be seen in those of the deposition types (see Deposition types).

One embodiment of the device according to the invention consists in that the application device has a functional head, at least one reservoir with a liquid-carrying tube ending in the functional head, the reservoir contains at least the liquid with the metal and the means for separating this metal, the liquid from the reservoir reaches the functional end via the tube, the functional end is a tube provided with a membrane that is permeable to the liquids and their components, the liquid exits the functional head through the membrane, this membrane lies against the object surface and at the same time in a

or two-dimensional direction parallel to the support surface alternately.

In this embodiment, the metal is applied from stable solutions using the reduction deposition method (see also deposition methods).

One embodiment of the device according to the invention consists in that the aforementioned device has an external power source, the anode of which in the functional head is in direct connection with the liquid, the cathode of which has an electrical contact with the metallic object surface.

In this embodiment, the metal is applied from stable solutions using a deposition method with an external power source, whereby the anode is an inert metal and the reducing agent is oxidized on it (see also deposition methods).

One embodiment of the device according to the invention consists in that the application device has a functional head, at least one reservoir with a liquid-carrying tube ending in the functional head, an external power source, the reservoir contains at least the liquid with the metal, the liquid from the reservoir reaches the functional end via the tube, the functional end is a tube provided with a membrane permeable to the liquid and its components, the liquid exits the functional head through the membrane, this membrane rests on the object surface, is simultaneously moved alternately in a one- or two-dimensional direction parallel to the support surface, the anode of the external power source in the functional head is in direct connection with the liquid, and the cathode has an electrical contact with the metallic object surface.
In this embodiment, the application of the metal

II »I « * I I · · I I

&bull; ttt · t · ■ * · r - · * · Iff

tails from stable solutions according to the type of deposition with an external power source, whereby the anode represents the metal that dissolves through oxidation (see also types of deposition).

The last three embodiments mentioned serve to apply the metal to the metallic surfaces in order to improve their surface finish. They are characterized by their functional head, which will now be described in more detail.

This functional head corresponds to a tube which is angled at its end and widened in a funnel shape and which is closed with an elastic membrane (perforated plate) (44) with a low surface roughness and which is permeable to the solution. However, this membrane is impermeable to liquid in the area where it is suspended at the end of the tube, i.e. in its peripheral part (4 ^r >). Liquid can only escape from the functional head through the pores (holes) (46) in the central part of the membrane (perforated plate). During the working process, both parts of the membrane lie flat (congruently) against the metallic surface to be coated, i.e. its actual surface. Liquid can only escape from the functional end through the membrane in this state to a very small extent or not at all. The only drainage route available is the space between the actual surfaces of the membrane and the object surface (48). During the deposition process, the functional end or the membrane adjacent to the object surface is moved alternately in a one- or two-dimensional direction of movement parallel to the object surface. At the same time, the pressure in the tube end is increased by means of the pressurization device so that the metal salt solution escapes through the membrane while it slides on a thin liquid film.

In order to prevent a possible build-up of liquid under the membrane by applying the liquid-impermeable

texls, the membrane can be supported at the transition between the two parts with a ring (50) which has radial recesses (51).

The deposition without an external power source takes place according to the principle of reduction deposition. This means that the metal can only be deposited on metallic surfaces, i.e. on the object surface. Unstable solutions would immediately clog the membrane pores.

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The anode (53) is located inside the functional head and is surrounded by the metal salt solution (">M). It has a flat arrangement with a parallel alignment to the cathodic object surface in order to ensure the homogeneity of the electric field.

The processes will now be described in more detail using the example of galvanic deposition.

The metal can only be deposited at points that are in electrical contact with the cathode, are wetted with the solution and are in electrical contact with the anode via the solution as a second type of conductor. Due to the movement of the functional head on the surface to be coated, the deposition takes place primarily at points that have no or rarely mechanical contact with the moving membrane surface (55). In Figure 12, the surface relief of the surface to be coated is shown in cross-section, greatly enlarged, for better illustration. The membrane surface that is in "flat" contact with the actual surface (48) is, when viewed more closely, only in mechanical contact with the object surface (56) at the highest elevations due to the surface roughness. If the galvanization were to take place without the movement of the membrane, there would be the problem of the uniform flow of metal ions to all parts of the surface (diffusion transport in the weak electrical

see field / different lengths due to random position of the membrane pore), on the other hand, the insufficiently smooth surface of the membrane (pores) (46) would lead to further increases. Due to the one- or two-dimensional alternating movement of the membrane parallel to the surface with a minimum amplitude of the average pore spacing, the metal deposition takes place preferentially at deeper points of the surface relief (55) until this is almost flat. The elasticity of the membrane must be large enough to ensure its adaptation to the curvatures (macroscopic) of the object surface. The surface adaptation of the membrane to the object takes place through the (dynamic) overpressure generated in the reservoir, but can also be supported by an elastic, sufficiently liquid-permeable "cushion" that rests against the inside of the membrane under pressure. The membrane material must not show any signs of abrasion during the working process in order to exclude the inclusion of abraded particles. In addition, the voltage of the external power source can be controlled by the movements of the function head. To avoid excessive contact forces by the practitioner, spacers can be attached to the edge of the function head.

This deposition process also has the advantage over the electroplating process for polishing a workpiece that only the smallest amount of metal needs to be applied to obtain a smooth surface. This also means that the processing time is shortened.

All three of the above-mentioned designs enable localized metal deposition to improve the surface with such a functional end. The advantages and disadvantages of the individual devices can be seen in those of the deposition types (see deposition types).

The movement device is described below together with the treatment shafts, following the description of the functional devices.

,j^, An embodiment of the device according to the invention consists

F in that the>5 application device has a matrix-like 1

Device that transfers the prepared tooth into a vessel containing it/3, the functional head, at least one storage container with at least one liquid

_ ness-carrying pipe ending at the functional head, a suction

s device with at least one in the functional head ending

: pipe, in at least one storage container the

Liquid containing the metal and the agent for separating this metal, the liquid from the storage container passes through the function head into the vessel containing the tooth and at another point the liquid is removed from the vessel/3 using the suction pipe.

In this embodiment, the metal is deposited from stable solutions using the reduction deposition method (see also deposition methods).

An embodiment of the device according to the invention consists in that the aforementioned device has an external current source Ie, the anode of which is in contact with the liquid in the vessel

&Ggr; is directly connected and whose cathode has an electrical contact with the metallic object surface.

' In this embodiment, the metal is deposited from stable solutions in the manner of deposition with an external power source, with the anode being an inert

£ metal and the reducing agent at this oxi-

■ is separated (see also types of separation).

An embodiment of the device according to the invention consists in that the application device comprises a matrix-like device which transfers the prepared tooth into a vessel containing it, the functional head, at least one storage container with at least one liquid-carrying tube ending at the functional head, a suction

device with at least one tube ending in the functional head, has an external power source, the liquid with the metal is contained in at least one storage container, the liquid from the storage container passes through the functional head into the vessel containing the tooth, at another point the liquid is removed from the vessel with the suction tube, the anode of the external power source is in direct connection with the liquid in the vessel and the cathode has an electrical contact with the metallic object surface.

In this embodiment, the metal is applied from stable solutions using a deposition method with an external power source, whereby the anode represents the metal that dissolves through oxidation (see also types of deposition).

The last three versions are used to apply metal evenly over the entire surface of a tooth. The surface must be metallic or germinated.

The metal is deposited from the electrolyte bath. The function head consists of a pipe that supplies the solution and a pipe that removes it. Both are connected to a matrix-like device and ensure that the electrolyte concentrations are kept constant in the sense of flow equilibrium.

Particularly in the case of crown stumps, the supply can also take place via a bell-shaped, double-walled pipe (56) instead of a pipe, with the solution being supplied between both walls. The same applies to the suction pipe (57). The advantage of this form of supply is that the solution flows evenly along the tooth stump, which has a beneficial effect on the separation.

The embodiments are particularly characterized by the matrix-like device, which will now be described in more detail

should be described .

The matrix-like device [see also claim 36] consists of at least one sealing ring (59) and the matrix film (60) forming the matrix wall. The length of the sealing ring is adapted to the tooth to be treated, so that after insertion of the tooth surface, it rests with a rear tension in the tooth neck area in order to ensure sealing in the apical direction. However, this tension makes insertion more difficult. Therefore, the surface (oil) resting on the tooth should be large enough to make rotation about the circular longitudinal axis of the ring impossible or only possible with difficulty, thus enabling simple, safe insertion in vivo. On the other hand, however, its height (in cross-sectional view) must not be chosen to be too large in order to be able to reduce the risk of injury to the marginal periodontium. Such a sealing ring is shown in Figure 1A. When relaxed, its opposite inner surfaces diverge downwards, so that the circumference at the lower, thin end is larger than at the upper, more solid end. When placed in place, the lower part can easily be pulled over the preparation border. As it is pushed further down, the tension increases due to the ever-decreasing circumference. This tension is transferred to the lower part, so that this now also lies tightly against the tooth surface. The impermeability to liquids is based on the greater tension at the upper part.

A further form of administration of a modified matrix-like device is now to be described [see claims 52 and 56] [see claim 36]. The sealing ring is hereby filled with a chemoplastic, thin-liquid cement substance (62) and pushed into the gingival sulcus using a delicate but blunt instrument until its upper edge comes to lie slightly below the preparation border. Possibly when inserting

_ 3 3 &mdash;

Any excess material that has formed on the preparation surface is subsequently removed. The putty can also be applied to the gingival sulcus beforehand using a syringe. Due to its low viscosity, it flows into the depth of the gingival margin due to the pressure that occurs during insertion (as, for example, in the second phase of a corrective impression). After setting, it lies fluid-tight against the surfaces of the adjacent structures without causing mechanical or chemical irritation (63). The length of the ring is also tailored to the tooth to be treated. In contrast to the device described above, it functions here on the one hand as a connecting element for the matrix film and putty, and on the other hand serves to facilitate the insertion of the device. Its length is selected so that it lies against the tooth with slight tension. In cross - sectional view, it resembles the ring described above, but with a lower height. The material is also a rubber-elastic plastic that forms an adhesion with the putty. The cement substance should not bond to the tooth surface itself, or should not bond too strongly, in order to enable safe and easy removal later. The elasticity of the set plastic should also not be too great, so that any increase in pressure in the matrix space does not lead to fluid leaking through the apical section. The same applies, of course, to the sealing ring. The disadvantage of this form of administration compared to the former is the increased time required. However, this must be offset by the advantages of the latter. For example, inserting the device with cement substance is gentler on the surrounding anatomical structures due to its lower viscosity than would be possible with the ring alone. Consider, for example, the risk of injury to the ligamentum circulare when applying a retraction ring as part of a prosthetic or

preservative treatment. The safety I* regarding the impermeability to liquids is also

relatively large attachment surface is to be estimated to be much larger. In this context, attention should be drawn to the concave surface curvatures that are particularly common in the tooth neck area (e.g. mesial approximal surface of the upper first premolars). Here, the liquid-tight seal can only be achieved by means of the sealing ring with putty substance. The matrix film, which is firmly connected to the sealing ring or covers it, is a thin and liquid-impermeable film. It is formed into a vessel for the deposition from the electrolyte bath, possibly with the aid of equipment, to which the pipes of the functional end are connected. In addition to this special use of the matrix-like device, it should preferably also be used with the other functional devices described up to this point, but especially with the deposition using the spray method. Both the solutions and their precipitation usually have harmful effects on the adjacent structures.

To facilitate working with this matrix, the matrix wall can be secured with an intraoral fixation device

[see claim 30;37] into shape. This device is made up of, for example, the fixing clamps (6A) and a table (65). The table is attached to the adjacent teeth by the holding clamps. In the area of the tooth to be treated, it has a hole (66). The matrix wall (67) can now be pulled through this hole and attached to the sides of the table (68). The matrix with its wall made of a film thus becomes a relatively stable vessel.

Due to the low deposition speed of the latter-mentioned devices, the fixing device can be equipped with an additional device (69) which

firstly, it enables the functional head to be fixed to the table, and secondly, it ensures that the vessel that is still open in the coronal direction is sealed liquid-tight [see claim 31]. This makes it possible to fix the functional head to the table, to allow the supply lines ('/I) leading from the functional head to the device box to reach out of the patient's mouth (lip closure) (72), and to carry out a longer separation (10 minutes) while the patient (connected to the device) sits on the treatment chair. In this way, the advantages of the separations from the unstable solutions can be used despite the slow separation.

The device for fixing the matrix can be used in many other ways in addition to the example given above. Finally, one more example will be given.

Due to the harmful effects of many of the substances used here, it must be prevented that the patient swallows or aspirates the substances. To do this, the matrix wall is attached to the adjacent teeth using a fixing device (73) to prevent it from being pulled off accidentally. In analogy

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The correspondingly large matrix foil (74) is then pulled out of the oral cavity onto a corresponding holder frame. However, the fixing device does not have the form of a table described above. Here, the tooth to be treated must be accessible from all sides (e.g. for the spraying process), so that the fixation of the matrix wall to the fixing device is at the level of the alveolar ridge, for example (75). The security with regard to liquid impermeability is guaranteed by the apical liquid-tight seal. During the course of treatment, it is necessary to be able to bring the functional heads into the most varied levels and positions in the patient's mouth. This can be

This can be achieved by connecting the functional heads to the handpieces by means of a treatment shaft that holds the functional head in a corresponding position. A treatment shaft would be assigned to each position. This would mean that eleven different attachments would be required to deposit the metallic deposit in the cement joint on a tooth. However, this would involve too much effort, which would be caused by simply changing the shafts.

With the aid of a longitudinal axis shown in Fig. 1 it is possible to bring the functional end into all necessary positions with any position in the plane [see claims 34; 35]. The treatment shaft is a multiple joint rod (A) in which the number and length of the rods can be individually selected by the practitioner. In this example the joints are ball joints (see Fig. 17). The size of the joint socket (76) can be varied by the practitioner by means of a pin (77) acting as a wedge, or the ball (78) in it can be locked in place or mounted so that it can be freely moved for adjustment. It is important that the rigidity of such a treatment shaft is maintained despite the joints and rods. Because only in this way lcr oc Horn llohanilUr mnoltrh oval and with &Ggr;.&Ogr; feel hllnd TO

arbniten.

The treatment shaft shown in Figure 1 has two ball joints. Its proximal joint (80) enables the practitioner to assume the pen position, and the distal joint (81) allows the functional end to be brought into the desired position and level. Of course, it would also be possible to equip a treatment shaft with just one ball joint. However, this requires a great deal of freedom of movement in this joint, which inevitably results in a loss of stability. The number of joints and the length of the rods in a treatment attachment must be determined individually by the practitioner.

«fit ft» t &bull; · ti *| ,

In another type of joint, the joint consists of a hinge joint (83) and a rotary joint displaced into the rod (see Fig. 18). The latter consists of two joint parts (81 and 82) and is comparable to a male part (82) inserted into the female part (81). The male part is a cylindrical rod (8A) and ends with a conical anchoring head (85). This is locked in the female part (81) by a bolt (86). In the cross-sectional view (Fig.

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The cylindrical part of the male part (81) has a star shape. When the anchoring head is fixed by the locking bolt, a rotational movement around the longitudinal axis is prevented. In order to carry out a movement in the rotational joint in the sense of the joint, the practitioner releases the locking bolt by turning or applying pressure with his finger, pulls the male part out of the female part, turns it into the desired position and pushes it back into the female part until the locking device engages. The cylindrical part of the male part stabilizes the joint. The advantage of such a relatively complex joint construction is the greater stability, especially with a delicate shaft design. In addition, changing the position or location of a functional head during the treatment process usually only requires rotation around one axis. Due to the delicate design of some functional heads, it can be difficult for the practitioner to correctly identify the contact surface of the functional head. This is especially true if after a work step the position of the plane has been changed using a ball joint. In contrast, the position of the plane remains unchanged when rotating in the hinge joint. Thus, the three degrees of freedom of the ball joint described above can also have a detrimental effect under certain conditions.

The movement device of the functional apparatus for surface treatment is intended to move the functional head in a

one- to two-dimensional direction parallel to the object surface, i.e. also parallel to its support surface [see claim 24; 25]. The direction of movement must change accordingly when the position and orientation of the support surface changes. If the device were on the handpiece, it would have to be possible to change the direction of movement. However, this would involve too much effort. Figure 20 shows an example of such a movement device.

ral direction (see subclaim 14). It is mounted on the joint rod distal to the last joint (88). If the position or direction of the functional head or its support plane changes, the movement device is moved to the same extent. The functional head (87) merges proximally into the piston. This piston (89) is slidably mounted in the housing (90) of the movement device. At its end there is a plate (91) which is arranged at an angle of Δ5 to 90° to its longitudinal axis. At maximum piston excursions the plate moves in a space (94) which is delimited by a protective housing (92). Two compressed air pipes (93) which cause the movement of the piston end in this space. One nozzle is located below (95) and the other above (96) the plate. The outlet directions of the nozzles are set so that the escaping air pushes the plate away on the one hand and can also easily escape from the protective housing, i.e. without great air resistance. In order to obtain the alternating piston movement, the compressed air is supplied to the individual tubes alternately at the desired frequency. If the air supply is on the lower tube in one time interval, the piston moves upwards, and in the next time interval it moves downwards again. The force of the piston's movement is determined by the pressure, total resistance and the air transport rate. The length of the piston's path is determined by

Determine the distance between the front (97) and rear stopper (98). If the piston is also to be able to rotate around its longitudinal axis, the compressed air nozzles must also be rotated when the plate is inclined.

In order to continue to ensure that work can be carried out in the patient's dog, the movement device must be kept as small as possible, but this should not cause any major problems given the uncomplicated design. Furthermore, the distance between the function head and the handpiece should not be too large in order to enable maximum movement transfer to the function head. This is because the work generated in the movement device is absorbed to an ever greater extent as this distance increases. This effect is due on the one hand to the corresponding increase in elasticity of the treatment attachment and on the other hand to the decrease in the leverage of the treating hand.

In addition to the possibility of using the movement device for the functional device for surface finishing, other attachments can also be used instead of the functional head. For example, for mechanical surface treatment, such as cleaning and polishing hard-to-reach surfaces, especially the proximal surfaces. The devices available today for mechanical cleaning of the interdental spaces are primarily converted angle pieces from the drilling devices commonly used in practice. Here, the rotational movements are converted into alternating one-dimensional movements. However, these modified angle pieces have two serious disadvantages compared to the treatment attachment for mechanical surface processing described here. Firstly, the angle piece does not allow the functional head to change its relative position, so that certain surfaces cannot be reached, and secondly, the functional heads are too large to be able to reach the interdental space without damaging adjacent structures.

As already mentioned in the previous description, the tooth to be coated with a metal coating must be pre-treated. This post-preparation measure primarily concerns the surface treatment of the enamel substance that borders the cavity. This is because enamel is the only one of the three hard tooth substances that has sufficient adhesive strength when in direct contact with the metal coating. Pre-treatment includes cleaning, roughening or creating retention (preliminary use of acid etching), sensitization (preferably with tin-II-salt solution) and, if necessary, activation (e.g. with silver nitrate solution, palladium-II-chloride solution). The metallic deposit is then applied to this pre-treated surface.

The application of the substances can be achieved in a simple manner by means of a spraying or squirting device according to an embodiment of the device according to one of claims 39 to 41. Such a device corresponds to the spraying and squirting devices already described with the difference of the solutions used [see claims 42 to 46].

However, in the context of conservative and prosthetic treatments, the preparation border on a treated tooth is not always in the enamel area. For example, when a tooth that has been severely damaged by caries is being treated with a crown. Here, the preparation border is in the area of the cementum. The same applies to the very advanced destruction that is often found, particularly on its approximal surfaces far cervically, on an otherwise relatively well-preserved tooth. In order to be able to effectively provide such teeth with a filling or crown using the device according to claim 1, they require further pretreatment. Before this is described, however, another point about filling or crowning therapy should be addressed.

When a tooth is filled or crowned, the aim is to achieve the strongest possible bond between the filling material or cement and the hard tooth substance. If the enamel were the only hard tooth substance available for such a bond, the adhesion of the filling would be limited or impossible due to its small surface area. This is particularly problematic if the preparation border does not consist of enamel or only consists of a small amount of enamel. Here, for example, the thin layer of enamel in the cervical third of the approximal surfaces (?,·■%) must be considered. Therefore, attempts are made to involve dentine and cecum in the bond between the tooth and the filling, in addition to enamel. Chemical adhesion has so far been achieved by using special cements which form a chelate bond with the calcium ions in the enamel and dentine (e.g. glass ionomer cements, carboxylate cements). Some time ago, the so-called dentine adhesives based on PMMA plastic came onto the market. Here, a catalyst called tri-n-butyl borane (TBB) is added to the polymethyl methacrylates (PMMA), which greatly increases the wetting ability of the dentine surface. The high adhesive strength is based on the chemical bond of the acrylate to a tertiary carbon atom of the L-alanine in the dentine collagen. This precursor of MASUHARA was followed by an improved adhesive (e.g. SUPERBOND) by adding an acid anhydride (4-metharyloxyethyltrimethyl anhydride, or 4-meta for short). Dentine adhesives with aryl sulfinates as an additive based on the plastic of the diacrylates of the Bis-GMA type (e.g. COTCHBOND) are also available on the market. [Lit.: Practice of Dentistry Vol. 2, 2nd edition 1987, Urban-Schwarzenberg-Verlag, page 186 ff.].

A tooth to be coated with the metallic coating, where the preparation border is located in the area of the dentin or cementum, is prepared in the usual way

up to the treatment step before inserting the filling or crown (e.g. underfilling, cement build-up). The tooth is then provided with a thin layer of dentine adhesive up to or slightly beyond the preparation border. This plastic coating is firmly bonded to the dentine and cement. The metallic coating is then deposited on its surface. In order to achieve a high level of adhesion to the plastic coating, this is subsequently coated with another special plastic layer (- also possible in a single phase and one step). This plastic is essentially the same as a conductive varnish used in the galvanization of non-conductors. The finest metal chips are added to the plastic monomer of the dentine adhesive (e.g. MMA monomer), which should be located particularly in the surface area of the hardened plastic. The surface of this plastic layer must be at least partially taken up by the metallic surfaces of the chips. In order to achieve this, it is possible to apply the plastic enriched with metal particles in the first step and then to remove the hardened plastic surface in the second step until a sufficiently large part of the surface is taken up by the metal particles. In another one-sided procedure, the metal particles are hurled or rather shot at the surface of the not yet hardened plastic using a special gun [see claims 47 to 51]. Such a device also corresponds to the device already mentioned above with the difference that it only allows the powdered solid to be applied.

By using metal particles as a bonding agent, the adhesion between particles and metal coating is based on the metallic bond, ^while the adhesion between particles and plastic is based on the retention of the particles in the plastic matrix.1

&bull; · · · «ftf . &igr;

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A modified form of metal particles is particularly those with a firmly adhering oxide layer. Metals that can form a firmly adhering oxide layer on their surface, such as zinc and copper, are provided with their oxide layer in a controlled oxidation process. Polyacrylic acid is able to form a chemical bond with the oxides of some metals via a chelate-like bonding of the metal cations (such a bond is present, for example, in carboxylate cement with zinc-II-oxide). After the plastic coating provided with the particles has set, the oxide layer on the particles is removed mechanically or chemically. The surface pretreated for the precipitation deposition is formed partly by the metallic surfaces of the particles and partly by the plastic matrix. By using metal particles with an oxide layer, the adhesion between particles and plastic matrix is based not only on their retention but also on the chemical bond between metal oxide and plastic.

Before we now go into the advantages that can be achieved with the invention, a few points about the device should be mentioned.

Due to the solutions (precious metals) being more expensive and having a limited shelf life, as well as the sensitivity of the deposition result to contamination - the transfer alone would result in unavoidable contamination - it is preferable to supply the substances in cartridge form. The special cartridges supplied by the manufacturer are inserted into the device and connected to the corresponding supply lines. The solutions are delivered to their functional heads by means of pressure.

The metals deposited on the teeth in this process must be inert to attacks from the oral cavity. This includes precious metals, and metals that have been rendered "noble" by passivation (e.g. chromium).

Basically, it should be remembered that the metal that is in direct contact with the tooth structure preferably has ductile properties.

A special procedure should be noted when it comes to amalgam fillings. The metallic coating applied to the cavity surface is a metal or alloy that can be amalgamated with the amalgam, so that the filling is chemically bonded to the metallic coating.

The advantages achieved with the invention are in particular that/3 the application of adhesive metallic coatings on teeth and foreign materials on the teeth is possible by means of the cerate according to claim 1, since/3 these coatings can be applied in their peripheral areas in layers as thin as fractions of a micrometer, thus preventing a transition from metal to the hard tooth substance

Altna Do«-»*4ow\£»l*- i> &eegr; f 1 { &dgr;&eegr; f

&ngr; ■■ -■ ^, ■nwaiuvf^u^-L, &ngr; w a. ·. &agr;&ngr;* Q ^. ·

As a consequence of these advantages, further achievable advantages arise for the procedure explained above. These consist of the improved filling or crown edge design on a tooth treated with a filling or crown, the resulting improved protection of the remaining tooth hard substance, particularly in the filling edge area, from chemical destruction and the prevention of subsequent periodontal damage in the area of the treated tooth.

To more precisely explain the effect of the metallic deposit on a tooth, consider a conventionally prepared tooth, appropriately pretreated and provided with a metallic coating before insertion.

&mdash;45&mdash; * » e»«>:ItSS

&bull; f · · I · I

'&igr; II j

placing the filling or crown. If such a "half-supplied" tooth were exposed to the oral environment for a longer period of time, the metal coating would provide greater protection from chemical destruction of the remaining tooth substance in terms of chemical attack than a conventionally applied filling could provide. This astonishing comparison becomes clearer when one takes into account what was explained in detail in the introduction to the criticism of the state of the art.

&iacgr;&iacgr;&igr;&Egr;&Ggr; ViUTuC uxe UTiZU L" ei C li e &Ggr;&igr; u dissolved filler material and the design of conventional fillings have been described as the causal factor in the development of secondary caries. The fact that even in the case of a tooth with only a metal coating, the edge area of the coating represents the critical point of attack is obvious. Just like a conventionally processed filling, the metal coating is also impermeable to the aqueous solutions from a minimum thickness of a few micrometers, so that the chemical attack, provided the coating is chemically inert (ie does not dissolve itself), does not take place over the entire surface, but mainly at the transition line between the coating or filling material and the tooth hard substance, nia r.tctalHino itec ilhoroanochoroi rhps &Lgr; P s mpt.al I &iacgr;-&mdash; __- ___ _ &mdash;_&sgr;&mdash;&mdash_{; &sgr;}&mdash; __ &mdash;&mdash; __ - _ _ -.- -

The adhesion of the coating to the tooth hard substance is therefore the decisive factor in the high resistance to secondary caries. The metallic deposit adheres well to the enamel surface due to the micro-retentive relief previously created by etching and the resulting surface enlargement. The optimal filling of the micro-retentive spaces on the enamel surface with the deposited metal can be clearly seen in the electron microscopic images from the field of plastic electroplating. [Lit.: Practical Galvanotechnology, E.G.Leuze Verlag 1970 page 338 fig. 135/173 et al.]. It is still unclear whether, as with composite fillings, a chemical bond is present.

is -/

· ■ · · 1 > 1

[- a chemical connection could possibly be present via the tin-IV ions, which on the one hand form a poorly soluble salt compound with the phosphates, and on the other hand could form a bond with the precipitating metal in the sense of oxide adhesion -]. The

The elasticity mentioned in the material fillings as a further prerequisite for good adhesive strength can be achieved here by using ductile metals (silver, copper, gold) as the base material.

: coating layers. The thin, tapered edge

ClIU All U GIl LlClllll^lU UUCLgCUCUUC tlCUCtAAULrCLCjUg^ gCtTUHl-ACAO*.*-*.

\ iu long-term prevention of the development of a reten-

tion area for the cariogenic microorganisms. Then, after a longer period of wear, there is a slight dissolution of the metallic coating, e.g. by certain ions in the saliva - rhodanides and cyanides can even dissolve in the presence of air, forming complex salts.

V Dissolve gold; the former are almost always, the latter with the

f Consumption of certain foods and beverages present in the saliva (Lit.: Dental materials and processing, K. Eichner 5th edition, Vol. O - the material removal takes place over a large area. However, this leads to a qualitative impairment of the filling edge design.

i__ ttino. In addition, the !net^llisch^

Coating due to its thin layer application

;f can be placed beyond the preparation limit,

r. which further reduces the risk of secondary caries.

Disadvantageous properties such as excessive thermal expansion coefficient, setting shrinkage, swelling, discoloration or tissue-irritating effects are also not an option for the coatings.

If we now consider the tooth with a cemented filling or crown or after the plastic filling material has been introduced into the cavity, taking into account the partially modified procedures, but without further treating the filling or crown edge with the device, it is clear from the above description that in the case of a

— 47 &mdash;&bull;&bull;&bull;■»&bull;tiiiot«

&bull;ti··« c

I ,1 Ii I

In such a tooth, the risk of secondary caries is reduced to a minimum. If we look more closely, there are two filling edges here. The first, which represents the actual filling edge, is located at the transition from the metal coating to the tooth hard substance. The second is located at the transition from the filling material to the metal coating. The latter is not involved in the development of secondary caries, as there is no contact with the tooth hard substance. The surface depression present at this filling edge, which can cause retention of pathogenic microorganisms, does not cause secondary caries. However, after a sufficiently long period of wear, bacterial products can have harmful effects on the periodontium.

By depositing the metallic precipitate in such a surface depression at the edge of the filling, this unevenness can be filled with the precipitated metal. This avoids or reduces to a minimum any periodontal damage resulting from filling therapy. Another advantage achieved by the invention is the wider usability of dentin adhesives to increase the adhesion of filling or crown material to the tooth.

If, for example, during conventional filling or crowning therapy the tooth were to be coated with dentine adhesive to improve adhesion, the disadvantageous properties of the plastics would have to be accepted. The plastic used is in direct contact with the oral environment in the area surrounding the filling, so that in addition to swelling and being washed out, the release of substances harmful to the tissue (residual monomer) is to be expected.

However, these properties of the plastic are prevented by the metallic coating, which is firmly bonded to the metal. The liquid impermeability of the metal layer is the decisive factor.

■ ■ ··

Factor that prevents monomer diffusion into the oral cavity and water diffusion into the resin mass. In addition to the indication of dentin adhesives on teeth with preparation margins in the dentin or cement, it should also be noted that a cavity completely surrounded by enamel can also be coated with dentin adhesives on its dentin surfaces in order to achieve proper adhesion. However, the enamel surface must be left free, which is then provided with the metallic coating.

The essence of the invention is explained in more detail below with reference to an embodiment shown schematically in the drawing.
Show it

Fig. 1: A functional apparatus

Fig. 2: Function head of the spraying process

Fig. 3: Function head of the spray process

Fig. A: Function head of the local spraying process

Fig. 5: Function head of the local spraying process

Fig. 6: Function head of local reduction deposition

Fig. 7: Function head of local reduction deposition

Fig. 8: Function head of local reduction deposition

Fig. 9: Handling of the equipment for localized

Separation

Fig 10: Function head for surface treatment

Fig 11: Tools for explanation

Fig 12: Tools for explanation

Fig 13: Matrix device

Fig 14: Matrix device

Fig 15: Deposition from the electrolyte bath

Fig 16: Matrix device

Fig 17: Multi-joint articulated rod

Fig 18: Multi-joint articulated rod

aar· · ■ · ■

· · · ··· ItBSt

t · ·· 31 I

Fig 19: Multi-joint articulated rod
Fig 20: Movement device

Claims (1)

■ I &bull; » t » &igr; 1. Device for applying a metallic jg substance on teeth or on the teeth % foreign materials, I characterized by a container for a metal f 4&Ggr; containing liquid., e:re .in these connected £ ,' Device for applying and applying the ^; $r- liquid and a separator for the &bull; \ Metal from this liquid. % 2. Device according to claim 1, '- &lgr;&ogr; characterized in that the application device consists of -!; a connected to the storage tank i' compressed gas (air) operated spray device, and that the device for separating the metal from the ■;<! Solution from another to a reducing agent &bull;&iacgr;*&Ggr; containing container connected '·.'. compressed gas (air) operated spray device, whose '■ Beam direction to the same point of impact of the first sprayer. fä 3. Device according to claim 1, 'if xo characterized in that the application device and ■.J the separator consists of a Sprayer connected to storage container. || wUdei a pressure vessel for a reduct &igr; onsmi t'.e 1 i ^: containing gas with a device for d 1S~ Pressurization via a pressure line to the t| Spray nozzle is connected. fc'i! § 4. Device according to claim 1, ^;! characterized in that the container for the metal containing liquid a device for ■ '· 30 pressure application, the application device? i- consists of a spraying device, and that the device ''.'. for separating the metal from the solution from a A ^- ? further to a container for a reducing agent containing liquid, the spray direction of which is aimed at the same point of impact of the first spray device. f> . Device according to claim 1. J~ drviiirc'n characterized in that the container for the fluid containing the liquid connected to the order line has a device for applying pressure to the liquid and is connected to the outlet pipe of the liquid via a pipe leading to the flow of liquid. &Iacgr;&Ogr; On the contract word lrhtuny is connected'. (i . Device according to claim 5. characterized in that the device for separating the metal from the solution is connected to a container for a liquid containing a reducing agent with a device for pressurizing it, which is connected to the outlet pipe of the separating ^device via a liquid-conducting pipe. 7. Device according to claim 1, characterized in that the application device and the separating device are arranged in a container for a liquid containing a metal reduction solution, with a device for pressurizing it, which is connected to the outlet pipe (s) of the application and separating device via a liquid-conducting pipe. 8. Device according to one of claims 1, 4, 5, 6 or 7, characterized in that it contains a power source with a cathodic connection point for the patient or tooth electrode and the separation device has an anode connected to the latter. &bull; t I > · I I I « 9, Device according to claim 1, characterized in that the deposition device is a cathodic connection point for a petrochemical body on the surface. s~ 10. Device according to one of claims 1 to 1, characterized in that the device has at least two light sources, the light cones of which intersect. II. Device according to claim 11. The coating is characterized in that the light cones have a relatively small scattering angle and that the intersection point of both light cones lies in the plane ^of the impact point of the application and separation device. *f IZ. Device according to one of claims 10 or 11, characterized in that the intersection point of the light cones from the point of impact of the separating and applying device within the plane 13. Device according to one of the claims 10 to 12, characterized in that the light cones intersect at a relatively large angle. 14. Device according to one of claims 10 to 13, characterized in that the light sources have different colors. 15. Device according to one of claims 1 to 4, characterized in that it has an external suction device. · 16. Device according to claim 15, characterized in that the external suction device has a handpiece with interchangeable funnel attachments of different sizes. 17. Device according to one of claims 1 to characterized in that the application device connected to the storage container and the Vi/ iH \//~.vv* j n P'ttrilrt- &tgr; r\ r _t c: Ir r» &eegr; f are housed. 18. Device according to claim 17. characterized in that a support cushion is attached to the radio head. 19. Device according to claim 18, characterized in that the edge of the support bowl is at least partially raised compared to its central portion and at least the outlet of the application device connected to the storage container ends within the central portion. 20. Device according to claim 19. characterized in that the separating device ends in the middle part of the support cushion. 21. Device according to claim 18, characterized in that the middle part of the support cushion lying below the support level is divided into a front and rear chamber by a crossbar at or slightly below the height of the support cushion edge, whereby at least the end of the application device connected to the storage container ends within the front chamber. &bull; · I f · t &igr; 111 > · 22. Device according to claim 21. This means that the aortic separator ends in the anterior chamber of the sphincter. 23. From ichtuny after a^m of the ansi'VMf'ne i '..' until thereby i^'Kerinzp &igr;c'rui*·': . <jaß d&igr; ^|J Anc'de -ier external power source i ^r mit' ieren Te;! des A* ■ &igr; 1 agek &igr; ssen: inserted and.'. and partly c: ¹ ' »surface in the middle »..&tgr;&igr;&Iacgr;>.■ : 1 des Aiif !aaekisRens einriiirini*: 24. Device according to one of the claims 1'-' M^ ^{characterized} in ^that the A: ode ;·.&igr;A'.'tif.i'Jek&igr_; ^&rgr;&rgr; with its surface only slightly below the kissed edge. 25. Device according to one of claims iy to 24, characterized in that the '.inter de::: level d-.-· -"**" On 1 a-^ki ssenrandes ii ^f end portion ae? On . a ¹ .· ■ ³ ,· ^/ : &igr; ssens lying^ T^ii at least partially v.\:~ P i : ei: ^i ■·.:■'■· get ^; '. 1'. is. 26. Device according to claim ib. dadu: eh characterized in that the cover for the liquids in the container is a membrane or support layer which closes the liquid outlet opening of the functional head. 27. Device according to claim 26, iS characterized in that the membrane is a perforated plastic film. 28. Device according to claim 26, characterized in that the cushion consists of a liquid-absorbing fluid layer, e.g. made of foam or cotton wool. 29. Device according to claims 26 to 28, characterized in that the anode is at least partially covered by a support cushion. 30. Device according to one of claims 26 to 29, ■5" characterized in that the anode is supported directly on the support cushion. 31. Device according to claims 19 to 30, characterized in that the anode is at least partially designed as a grid, perforated plate or gap plate " ^e is arranged. 32. Device according to one of claims 26 to 31, characterized in that it has a movement device with a one- to two-dimensional movement direction. tr 33. Performance according to claim 32. characterized in that the movement device has a compressed air connection. 34. Device according to one of claims 4 to 9, characterized in that it comprises a device for the liquid-tight separation of the portion of a tooth protruding into the oral cavity from the surrounding anatomical structures. 35. Device according to claim 34. characterized in that the separating device comprises a resilient , liquid -impermeable film, e.g. a plastic film, with a hole. 36. Device according to claim 35» characterized in that the film is reinforced at the perforation point with a rubber-elastic tension ring, the circumference of which in the relaxed state -^ is smaller than that of the object at the d". e. 37. Device according to one of claims 35 or 36.. characterized in that the film and/or the tension ring has good adhesion with a plastic &iacgr;&ogr; state of the chemoplastic or thermoplastic cured putty substance applied. 38. Device according to one of claims 34 to 37, characterized in that the separating device is a gesture 1!device with tooth clamping and ■is tooth retaining elements. 39. Device according to claim 38, characterized in that the film has a rigid closure frame on its outer edge and the frame device has a holder for &iacgr;&ogr; liquid-tight fastening of the closure frame. 40. Device according to claim 39, characterized in that the functional head has a closure cover with holes for receiving the 2S supply lines of the application and separation device. 41. Device according to one of claims 2 to 9. characterized in that it comprises an ultrasonically operated atomization device. 42. Device according to one of claims 17 to 41, characterized in that it has an internal suction device. 43. Device according to claim 42, ■&Ggr; characterized in that the suction device is arranged via a pipe in the common functional head. 44. Device according to claim 1, characterized in that it comprises one or more devices, the liquid container, device for urinary tract preparation, suction pump, electric current source and the like are housed in a table or trolley box or in a dental treatment unit, the function head, spray nozzle and the like are tr a handpiece with treatment attachment and whose connecting lines are housed in a flexible supply hose. 45. Device according to claim 44, characterized in that one or more elements ZO of a device are part of several devices. 46. Device according to claim 44. characterized in that the handpiece has a holding device which has a connection point on the ² ^ handpiece and at the functional end of the device, 47. Device according to claim 46, characterized in that the holding device is a multi-joint rod. &igr; »· ■ · 48. Device according to one of claims 1 to 47,
characterized in that they comprise cartridge holders each with a device for applying pressure to the
the cartridge, and that &Ggr; the replaceable cartridge inserted in the. Pacronenhal ::ei to the liquid-carrying in the
pipes reaching the functional end.