DE102011000046A1 - Method and apparatus for disrupting a connection between an implant and biological tissue - Google Patents

Abstract

The invention relates in particular to a method for destroying a connection formed between an implant (1) and a biological tissue (2). It is provided that energy is applied to the implant (1) in such a way that the implant (1) is heated at least to a predetermined destruction temperature at least at an interface with the tissue (2).

Description

The invention relates to a method and a device for the destruction of a connection formed between an implant and a biological tissue.

In dental implants, the bone tissue of the jaw grows into or onto the surface of the implant (so-called osseointegration). The implant should normally remain in the jaw. However, with infections or jawbone shrinkage, it may sometimes be necessary to surgically remove the dental implant. However, such subsequent surgical removal of the dental implant is usually very expensive and associated with high bone loss.

The object of the invention is to avoid or at least reduce these disadvantages. In particular, a method preceding the removal of the implant and a corresponding device are to be specified, with which a downstream mechanical removal of the implant can be simplified.

This object is solved by the features of the independent claims. Refinements and developments of the invention will become apparent in particular from the dependent claims.

A first aspect of the invention relates to a method for at least partially destroying a compound formed or existing between an implant and a biological tissue.

The implant may in particular be a dental implant, and in the tissue around bone tissue, for. B. of the lower jaw.

In particular with dental implants, in general also with other types of implants, it may sometimes be desirable for reasons of improved mechanical retention that adjacent or surrounding tissue, in particular bone tissue, grows into the dental implant or infiltrates it at least in the surface area. The resulting improved grip is indeed for the intended mechanical loads of advantage. However, the removal of the implant, which is usually surgical, is made considerably more difficult by the stronger connection between implant and tissue.

In particular, to simplify the removal of the implant according to the invention, the actual, z. As surgical, distance upstream, to apply the implant with energy. The application of energy should be such that the tissue is necrosed at the interface to the implant and / or that the tissue is heated at the interface to the implant to at least a predetermined destruction temperature and / or that the tissue at the interface to the implant by vibration is replaced.

The term "compound" is to be understood essentially as meaning any association, adhesion, infiltration, adhesion and the like of tissue and implant, in particular so-called osseointegration, in particular by biological processes and activity, growth or regeneration. By way of example and without limitation of the generality should be mentioned that a compound according to the invention may arise, for example, by the fact that bone tissue grows into porous or open-pored surfaces of the implant.

The terms destruct, destruction, etc. are intended to mean that the compound is at least partially, e.g. B. part of the area, weakened, dissolved and / or destroyed. Thus, the required at least partial destruction in the range between local weakening of the compound up to the breaking up of essential parts of the compound. lie. The respectively reached and achievable degree and extent of the destruction may be dependent on z. Example of the type of tissue, the shape and the surface condition of the implant, the material of the implant, the nature and density of the impinging energy and other factors.

A second aspect of the invention relates to a device for at least partially destroying at least one connection formed or existing between an implant, in particular a dental implant, and a biological tissue, in particular bone cells, which device is preferably provided for carrying out the method according to the invention. The device comprises a trained to energize the implant with energy energy source, wherein the energy is adjustable or adjusted so that upon exposure of the implant with the energy, the tissue is necrosed at the interface to the implant and / or is heated at least to a predetermined destruction temperature and / or is replaced by vibrations.

This energy source can be coupled to the implant to heat it either mechanically or by other interaction. The energy source may in particular be a sound source, in particular a high or high frequency sound source, in particular an ultrasound source, a heat source, in particular an electric heat source, in particular resistance heating, and / or Heat radiation source, an induction source or a radiation source for electromagnetic radiation, in particular light or infrared, in particular a laser act. Any combination of these enumerated energy sources can also be used.

Advantages and advantageous effects of the device according to the second aspect are particularly evident from the comments on the first aspect of the invention (method).

Preferably, at least the implant is heated at least at its boundary surface or boundary layer to the tissue to at least a predetermined destruction temperature. As a result of the application of energy, at least the implant is heated. Under certain circumstances, and depending on the type of energy source and type of implant material, there may also be an immediate warming of the tissue. However, a heating caused by the implant is preferred. As a result, the respective connections to the respective implant can be more selectively destroyed.

In particular, heating of the implant leads to heating of at least the interface or boundary layer between implant and tissue, in particular via heat conduction processes which take place readily between implant and biological tissue. In that regard, heating of the implant is associated with heating of the tissue. Such heating to or above the destruction temperature leads to at least partial destruction of the compound or compounds if several different types of compounds are considered.

The destruction of the compound (s) can be achieved, for example, by at least partially necrotizing the tissue of the interface with the implant or the tissue of the boundary layer, preferably by supplying thermal energy or heating. The heating of the tissue by heat conduction processes on the implant is especially in hard to reach places, eg. As the jawbone tissue in dental implants, an advantage.

A destruction of the connection between tissue and implant can, particularly in bone tissue on dental implants, particularly advantageously at a temperature (destruction temperature) in the range of 40 ° C to 60 ° C, in particular at about 50 ° C, can be achieved, but the destruction temperatures can be chosen differently depending on the application and especially during the application may vary. At the stated values for the destruction temperatures, the tissue can be at least partially destroyed or necrosed, so that the compound (s) formed between the tissue and the implant are also destroyed. In this case, constant or variable temperature profiles can be used, in particular depending on the implant.

The energy supplied to the implant can be higher or higher-frequency sound energy, in particular ultrasonic energy, thermal energy, thermal energy, in particular electrically generated Joule heat energy and / or heat radiation energy, magnetic energy, eg. As induction energy, and / or electromagnetic energy, in particular light or infrared, preferably of lasers act. Preferably, an energy form or a combination of several forms of energy is used for which the implant has good propagation properties or interaction properties and / or which efficiently converts into heat energy in the implant. The abovementioned forms of energy are particularly suitable for the common implant materials such as metals, alloys, ceramics, etc.

Higher or higher frequency sound such as ultrasound can be coupled in via the implant, for example. The coupled-in energy can spread in the implant material and lead to a heating of at least the tissue located at the interface or boundary layer to the implant. By heating, the tissue can be necrotized, resulting in at least partial destruction of the connection between tissue and implant. However, the wave energy of the ultrasound, ie its vibrations itself, as such, can also lead to the tissue being at least partially mechanically detached from the implant, ie even without necrotizing heating. As such, the implant may be formed such that the ultrasound propagates anisotropically with a preferred direction toward the compound to be dissolved.

Heat energy may be applied by direct coupling of a heat source, such as a resistance heater or resistance heating wire, which is electrically heated by generating Joule heat, or a heat radiation source, to or into the implant, and heat conduction in the implant to necrotize the tissue. This is particularly advantageous for those implants which have good heat conduction properties. Depending on requirements, but also already the implant a corresponding location, mass or density distribution, z. B. in layers, slices or branches, having a good heat-conducting material, whereby an anisotropic heat conduction to the connection to be dissolved can be achieved. Through the targeted incorporation of suitable materials into the implant, which is particularly suitable for ultrasound energy and other forms of energy, In each case targeted, and in particular locally specific, necrosis can be achieved. Advantageously, the energy is coupled into the implant and distributed in such a way that at least the sites relevant to the detachment of the implant are necrosed, or the corresponding connections are released.

As far as possible, the above statements also apply to the use of induction energy. In this case, the implant is heated by Joule heat, which results from eddy currents generated by electrical and magnetic alternating fields and / or magnetization reversals.

In particular, for materials with pronounced ferromagnetic properties, induction heating can be used. However, inductive heating is also considered for materials with less pronounced or even missing ferromagnetic properties. As is known, eddy currents, which are converted into Joule heat in the material, are induced by time-varying magnetic fields as they occur during induction. With suitably selected magnetic fields, it is thus possible to heat the implant material purely via eddy current losses to the desired destruction temperature. This is all the more so as in biological tissue comparatively low destruction temperatures, eg. B. in the range of 50 ° C, can already lead to success.

A commonly used for implants material is titanium or alloys thereof, such as. Eg TiAl5Fe2.5. Titanium as such and, where appropriate, the alloys are not or only extremely weakly ferromagnetic. However, from the aspect of heating via eddy currents, such implants can also be heated to destruction temperature within a reasonable time frame.

As has been indicated above in connection with heat conduction and sound propagation, in the case of induction it is possible in an analogous manner to use ferromagnetic materials deliberately introduced into the implant. The ferromagnetic material may be provided in particular in at least one ferromagnetic induction region. This may be in the form of one or more layers, rings, lines, etc., or otherwise run in the material. The induction region may preferably be provided in spatial proximity to the regions in which destruction is to take place, for example in a near-surface layer of the implant.

The induction principle can generally be used to heat a ferromagnetic material which can be coupled to the exterior or the interior of the implant in order to heat it in a heat-conducting manner or is thermally conductively coupled. Depending on the type of coupling, it may happen that the induction energy leads only indirectly to the heating, and the actual heating takes place at least partially by heat conduction.

In order to avoid unwanted, in particular damaging, effects and effects of the applied energy on the surrounding tissue and / or on surrounding further implants and the like, it may be provided that a shield is used. The shield can be designed and arranged in such a way during the heating of the implant that the energy is essentially focused on a respectively desired or predefined effective range. Outside the desired or desired effective range, the shielding effect should at least be such that significant, in particular health, impairment or even damage can be avoided. Such a shield may include, for example, a radiation shield.

The shield can be at least partially enclosed by the implant and / or integrated into it. In addition to the thus achievable protective effect can thus be achieved a better focusing of the energy to the particular desired range of action.

Overall, it is found that the mechanical removal of the implant from the tissue can be significantly simplified and facilitated by the method according to the invention.

The energy supplied by the energy source (s) and / or the achieved destruction temperature can be measured or recorded in an advantageous development by means of at least one sensor. Thus, the destruction process can be monitored by means connected to the or each sensor control device, for example, gives a corresponding control signal to the dentist.

The invention will be further explained with reference to embodiments. Reference is also made to the drawings, in which

1 an embodiment with an external energy source, in particular induction source, for the destruction of a connection of a dental implant with the jawbone and

2 an embodiment of a device for breaking a connection between a dental implant and a jawbone with an insertable into the dental implant energy source are each shown schematically. each other corresponding parts and sizes are in the 1 and 2 provided with the same reference numerals.

The 1 and 2 show two embodiments of a dental implant 1 formed device according to the second aspect of the invention. From the description of the device results in particular the inventive method according to the first aspect of the invention.

That in a jawbone 2 located dental implant 1 is at least partially grown together with this. The latter is just desirable for the strength of the implant, but complicates the removal of the dental implant 1 ,

To the removal of the dental implant 1 To facilitate the device has an induction source 3 on, with which the connection between the jawbone 2 and the dental implant 1 at least partially destructible.

In place of the induction source 3 , or combined with it, however, can also be another source of energy, for. B. an ultrasonic or heat source or laser light source can be used. The following general embodiments can be largely transferred to any energy sources without further notice.

To destroy the connection between jawbone 2 and dental implant 1 becomes the source of induction 3 first in a suitable manner to the dental implant 1 , in the case of 1 laterally and externally positioned. The induction source can be positioned, for example, in the oral cavity or else outside the oral cavity. After positioning, the induction source 3 activated, so this one on the dental implant 1 acting magnetic alternating field (induction field) generates.

The alternating magnetic field interacts with the dental implant 1 and produced in the dental implant made of the titanium alloy TiAl5Fe2.5 1 Eddy currents. The eddy currents are converted into Joule's heat in the dental implant material, leaving the dental implant 1 heated.

So that the dental implant 1 can be heated faster, this has ferromagnetic material in the present case 4 in the form of layers, rings, or stripes, etc. By such, in the dental implant 1 embedded ferromagnetic materials 4 By inductively induced Ummagnetisierungsvorgänge additional heat can be generated, which allows for faster heating of the dental implant 1 contributes.

As a rule, the region (s) at which connections between the implant and tissue are to be formed or to be formed are specific to the respective implant. In that regard, the ferromagnetic materials 4 preferably be embedded in those areas at which the commonly formed connections between tissue and implant can be destroyed most effectively by heating. To think here is, for example, a near-surface embedding. Furthermore, z. As the volume or type of ferromagnetic material 4 be selected and formed according to the compound or compounds to be destroyed.

By a selective, targeted and in particular minimal embedding of ferromagnetic materials 4 At least undesired effects of such materials can be reduced. As an example, magnetic resonance examinations may be mentioned, which are only conditionally feasible for implants with high ferromagnetic components.

With sufficiently high induction fields, the respective desired heating can be done even at. Be limited to eddy currents in a timely manner. This is especially true at destruction temperatures in the range of 40 ° C to 60 ° C, especially around 50 ° C, which in dental implants 1 already sufficient.

At or above the destruction temperature, the bone tissue becomes at least in the interface between the dental implant 1 and jawbones 2 necrotic. As a result, the between dental implant 1 and jawbones 2 weakened or even destroyed existing connection. That in turn causes the dental implant 1 can be removed more easily.

The heating to the destruction temperature can be carried out continuously or in individual successive steps and / or with an approximately constant temperature profile, ie at a constant temperature or a specifically varying temperature profile in a temperature interval.

It is advantageous if the necrotizing effect can be limited or focused on the particular area of interest. Because it should be avoided by the induction source 3 In general, the energy source, tissue located outside the region of interest or desired area of action, etc., is compromised. To achieve this, the device has a shield 5 on, which are formed and relative to the induction source 3 and to the dental implant 1 it can be placed that the tissue and / or further implants not in the interest are not damaged and / or subsequently influenced.

After destruction of the connection between dental implant 1 and jaw tissue may be the dental implant 1 be removed in a surgical procedure. By the upstream destruction of the compound, the dental implant can be mechanically removed much easier. It turns out that the problem underlying the invention is solved.

In the further embodiment of the 2 is a dental implant 1 provided with a cavity 10 that has an internal thread 11 having. In this internal thread 11 was previously the dental crown, which in 2 not shown, screwed. It will now be an energy source in this embodiment 30 with an external thread 31 in the internal thread 11 in the cavity 10 of the dental implant 1 screwed in, leaving the energy source 30 very far in the dental implant 1 is insertable and thus very close to the necrotizing or to be heated surface areas within the jawbone 2 zoom ranges. The energy source 30 Here too, for example, an ultrasound source or a laser light source or an infrared source or simply a resistance heating element can be used.

When the dental implant 1 no such cavity 10 For example, the energy source may also be attached to, or brought into contact with, the free surface of the dental implant. Likewise, the energy source in the absence of an internal thread 11 in the dental implant 1 even only in the cavity 10 be introduced without screwing.

The energy source 30 is via a connection cable 32 , the light beam or the required other energy, such as electrical energy from a control device 15 or another supply unit to the power source 30 transfers.

The control device 15 is also via a sensor line 72 with a sensor 7 connected, for example, between the jawbone 2 and the gums or a lip 8th can be arranged near the dental implant to be treated 1 , The sensor 7 can the. Destruction process and monitor, for example, the depth of the imported energy source 30 ie how far the energy source 30 within the dental implant 1 or from its deepest point in the jawbone 2 removed, located, can measure. Depending on the measured or detected position or position of the energy source 30 relative to the dental implant 1 can the control device 15 then give a signal to the attending physician or even the power supply for the energy source 30 , in particular via the connecting cable 32 , interrupt.

Alternatively or additionally, the sensor 7 or another sensor, the temperature and / or intensity of the energy supplied to the dental implant 1 monitor. For example, a radiation sensor could be the one from the implant 1 heat radiation detected or an induction sensor detected by the energy source 30 or the energy source 3 Capture in FIG Inducted intensity. Such an embodiment with a control device 15 and a sensor 7 gives the attending physician the possibility of feedback on how far the procedure and the heating of the dental implant 1 are already advanced and whether the process can already be stopped, ie the tissue is already sufficiently necrosed.

Typically, the dentist will then wait a certain amount of time, for example one or more days, for the necrotized tissue to disintegrate or loosen and then the dislodged dental implant 1 from the jawbone 2 remove.

LIST OF REFERENCE NUMBERS

1

dental implant

2

jawbone

3

induction source

4

ferromagnetic material

5

shielding

6

crown

7

sensor

8th

Gum / Lip

10

cavity

11

inner thread

15

control device

30

energy

31

external thread

32

connecting cable

72

sensor line

Claims (10)

Method for at least partially destroying at least one between an implant ( 1 ), in particular a dental implant ( 1 ), and a biological tissue ( 2 ), in particular bone cells, formed or existing connection, wherein at least the implant ( 1 ) is energized such that the tissue ( 2 ) at the interface to the implant ( 1 ) is necrosed and / or is heated to at least a predetermined destruction temperature and / or detached by vibration. A process according to claim 1, wherein the destruction temperature (s) is in a range from 40 ° C to 60 ° C, especially at about 50 ° C. The method of claim 1 or claim 2, wherein at least one of the following forms of energy is used as the energy: higher or high frequency sound energy, in particular ultrasonic energy, thermal energy, in particular electrically generated Joule heat energy and / or heat radiation energy, magnetic energy, e.g. As induction energy, and electromagnetic energy, in particular light or infrared, preferably a laser. Method according to one of claims 1 to 3, wherein the implant ( 1 ) Comprises titanium or a titanium alloy and / or a ferromagnetic material ( 4 ), in particular a ferromagnetic induction region, in particular one or more induction layers. Method according to one of claims 1 to 4, wherein a shield ( 5 ), by which, at least in part, tissue ( 2 ) and / or one or more other implants outside a desired effective range is shielded from the application of energy, in particular the shield ( 5 ) at least partially from the implant ( 1 ) and / or integrated into it. Method according to one of the preceding claims, in which the supplied energy and / or the reached destruction temperature is detected or measured by means of at least one sensor and preferably also the destruction process is monitored. Device for at least partially destroying at least one between an implant ( 1 ), in particular a dental implant ( 1 ), and a biological tissue ( 2 ), in particular bone cells, formed or existing connection, in particular for carrying out the method according to any one of the preceding claims, wherein the device is a for applying the implant ( 1 ) energy source ( 3 ), wherein the energy is adjustable or adjusted so that upon application of the energy to the implant the tissue ( 2 ) at the interface to the implant ( 1 ) is necrosed and / or at least heated to a predetermined destruction temperature and / or is replaced by vibrations. Apparatus according to claim 7, wherein the energy source comprises or is at least one of the following energy sources: sound source, in particular higher or high frequency sound source, in particular ultrasound source, heat source, in particular electric heat source, in particular resistance heating, and / or heat radiation source, induction source, radiation source for electromagnetic radiation , in particular light or infrared, in particular laser. Device according to Claim 7 or Claim 8, in which the implant ( 1 ) Comprises titanium or a titanium alloy and / or a ferromagnetic material ( 4 ), in particular a ferromagnetic induction region, in particular one or more induction layers, and / or in which a shield ( 5 ) which is designed and positionable such that, at least partially, tissue ( 2 ) and / or one or more further implants outside a desired effective range is shielded from the application of energy, it is provided which shield is in particular at least partially removed from the implant ( 1 ) and / or integrated into it. Device according to one of claims 7 to 9 with and at least one sensor for detecting or measuring the energy supplied by the energy source (s) and / or the achieved destruction temperature and preferably with a control device connected to the or each sensor ( 15 ), which monitors the destruction process.

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