EP2579800A1

EP2579800A1 - Method for detaching a bonded connection by means of electromagnetic radiation

Info

Publication number: EP2579800A1
Application number: EP11787572.4A
Authority: EP
Inventors: Raimund Hibst; Ralph G. Luthardt; Karl Stock; Heike Rudolph; Katharina Kuhn
Original assignee: Stiftung fur Lasertechnologien In Der Medizin und Messtechnik An Der Universitat Ulm
Current assignee: Stiftung fur Lasertechnologien In Der Medizin und Messtechnik An Der Universitat Ulm
Priority date: 2010-06-10
Filing date: 2011-06-10
Publication date: 2013-04-17
Also published as: DE102010023394A1; WO2012019581A1; WO2012019581A9; US20130157212A1

Abstract

The invention relates to a method for reversibly securing an attachment part to a base part by means of a connecting means which rigidly connects these parts to each other. For this purpose, an adhesive separating material is disposed between the base part and the attachment part, said material losing its adhesive effect reversibly or irreversibly under the effect of electromagnetic radiation.

Description

METHOD FOR RELEASING A GLUE CONNECTION BY MEANS OF ELECTROMAGNETIC RADIATION

The invention relates to a method for the reversible attachment of an attachment on a base part by means of a firmly connecting them together

Lanyard, in particular, for the reversible attachment of dental restorations, fillings and brackets. Furthermore, the invention relates to a component for carrying out the method.

In many applications in the field of technology, medicine and the general area of life there is often the need to permanently connect two functionally related parts and, if necessary, to be able to separate them from each other without destroying them.

It is therefore an object of the present invention to provide a

Specify a method by which this is possible in a simple and reliable manner.

This object is achieved according to the invention in that between the base part and the attachment part

adhesion-promoting separating material is arranged, which under the influence of electromagnetic radiation his

Adhesive effect reversibly or irreversibly loses.

One possible application for this is found in dentistry, where crowns and bridges are used in the prosthetic restoration of teeth

attached to various dental fastening materials. These materials are a very heterogeneous mixture of material classes. In principle, two categories can be distinguished. These are on the one hand conventional inorganic cements, which

Ionic bonds enter {zinc phosphate, polycarboxylate, glass ionomer cements). On the other hand come organic

Materials used. The requirements for the composite crown / bridge tooth are manifold: it is not only important to secure the restoration against withdrawal and shear forces, but also a tight seal at the crown edge should be permanent. Temporary cements that allow the removal of the prosthetic restoration, however, can not meet the criteria mentioned. Consequently

Used materials that make an undamaged removal of dentures almost impossible. If one tries nevertheless, such a supply, without destruction of these, purely mechanically to dezementieren, it comes not infrequently to expelling ceramic veneers, fractures of the Build-up filling or even the tooth.

Furthermore, tooth-colored fillings (Kompositfüllungen) by the adhesive technique with the remaining

Tooth hard substance connected. The association to the

Tooth hard substance becomes over low viscous organic

Ensures connections, which in turn form a bond to the subsequently applied plastic filling material. The polymerization takes place chemically or by electromechanical radiation more suitable

Wavelength.

There are numerous indications in which removal of the intact restoration would be desirable. Fractures of ceramic veneers are reported in the literature as 3-10%. In the patient's mouth is only one

Inferior repair with plastics possible because

Ceramic must be fired at high temperatures. In the case of implant-supported restorations, the

Easing the abutment screw the decrease of the

Crown / bridge require. If bridges are loosened on a pillar, the construction often has to be separated in the mouth and thus destroyed. In addition to the above-mentioned technical indications for the decentralization of crowns / bridges, there are also such biological species. This refers to endodontic complications, the root canal treatment of crowned teeth

require. If the crown can not be removed, you simply drill through and repair the defect

then inferior with plastic or renewed the crown. As a result, unnecessary costs are incurred in many cases, which could reduce a reversible cementation method. Together, it can be determined be that currently a reversible cementing of

Dentures, under the condition of simultaneous clinical stability, is not possible.

Another area of application is the release of plastic, in particular tooth-colored fillings, which must be removed due to tooth decay or pain on the tooth.

Often these have, at least in proportions, still an intact bond to the tooth, which makes their removal much more difficult with good optical adjustment.

Another application for the reversible

Attachment offers orthodontics. As part of

Fixed "braces" teeth are stuck with so-called brackets. After treatment, these are usually mechanically blasted, with outbreaks of melt are to be mentioned as a possible complication.

In order to reduce the mechanical stress during the removal of the brackets, devices are known which heat the bracket via an electrical heating device until the adhesive softens. Especially in order to avoid injury to the patient by accidental contact with the hot instrument is in writing

US005205734A describes a device in which the heating of the bracket takes place via laser radiation. The supply of the laser light via an optical fiber, which is integrated in the pincer-shaped device.

It describes both the use of a laser wavelength that is absorbed by the bracket and the

Heating of the adhesive takes place via heat conduction, as well as the use of a wavelength at which the bracket is transparent and the heating of the joint about the absorption of the laser light by the adhesive itself. Disadvantage of the two mentioned

Devices is the potential damage to the tooth and the periodontium by too strong

Heat input into the irradiated area.

To use in this application, that is, in the reversible

Attachment of dental restorations, fillings and brackets, a particularly gentle release of the

Attachment is introduced into the joint fugitive light-absorbing material, which by absorption of radiated electromagnetic

Radiation of suitable wavelength leads to a disintegration of the compound.

Advantages over the cited prior art are in particular that the radiated energy in the

Verbindungsfuge is absorbed, i. exactly at the point where the energy is needed to dissolve the connection, and that in particular when using a

suitable (laser) light source with high pulse power other than purely thermal effects can be used to destroy the connection. Due to the irreversible damage of the fastening material can also be a successive solution of partial areas of the connection point, which in a reversible softening of a

Adhesive is not possible by heating. This allows the irradiated (laser) light output and thus the possible heating of the environment

Liaison with regard to a potential

thermal damage can be further reduced. The introduction of the absorber can be made by admixing with conventional dental fastening material or by producing a specially developed

Fixing material with suitable absorbers. In order to use common dental fastening material unchanged, for example, to avoid a reduced setting of the cement and to achieve a layer with higher absorber concentration and thus higher light absorption, alternatively, the absorber by applying an absorbent layer,

preferably on the dental restoration or the bracket, are introduced. Alternatively or additionally, the application of an absorbent layer,

possibly also in conjunction with a dental bonding system, to the tooth possible. An expected advantage is the residue-free removal of the cement on the tooth.

The absorbing material should have the highest possible absorption at the wavelength or

Have wavelength range of the selected light source. Soot particles are, for example, u.a. in the

Wavelength 1064nm of the Nd: YAG laser as absorber, because they have a high absorption in a wide spectral range.

To protect the surrounding area of the

Connection point and to bring as much light to the joint, the wavelength range of the irradiation is preferably to be chosen so that the highest possible transparency for the medium to be irradiated, ie the denture, the bracket, and / or the tooth is achieved. For example, the Fundamental wavelength of the Nd: YAG laser with 1064nm a relatively high penetration depth in dentin, enamel and in ceramic on.

Especially with ceramic dentures can from

For aesthetic reasons, the absorber be chosen so that it does not lead to visible discoloration of the joint. In addition, the absorber should be insensitive to normal environmental conditions, so that over time it does not lead to a deterioration of the bond.

The absorber and its concentration can preferably be chosen so that a particularly good mixing with the fastening material is achieved. In the case of stratified incorporation, good adhesion with the denture, the bracket or the tooth is desirable. When incorporated into the bonding is also a good mixing

desirable. Overall, as far as possible the further properties of the attachment, such as e.g. Bonding of the fastening material and adhesion, not negative

to be influenced. The concentration of the absorber can also be used to vary the level of absorption, for example in the case of larger layers in the absorber

Connecting joint to achieve sufficient penetration of the light. This is particularly advantageous if a destruction of the mounting material in the

Irradiation direction opposite region is desired. One possible application example is a lateral irradiation of the light to remove metallic brackets and the desired penetration of the light in the connecting joint to the middle of the bracket. The use of nanoparticles whose optical properties can be set in a defined manner and which can easily be mixed into fastening materials appears to be advantageous.

For a particularly effective photo-induced disruption of the polymer bonds of composite materials is the

Integration of a photodegradable absorber in the composite matrix possible. Again, integration into the mounting material itself or possibly in the bonding is possible.

In particular, the choice of the (laser) light source, the nature of the destruction of the compound can be determined. To avoid thermal damage to the tooth and / or the dental restoration or bracket, the use of lasers with a short pulse duration, femtoseconds to several microseconds, and higher appears

Light output in the pulse makes sense, whereby a largely athermal destruction of the attachment takes place.

For example, using the Er: YAG laser and a suitable absorber, the solution may be solubilized by thermo-mechanical ablation. Alternatively, for example, when using a Q-switched

Nd: YAG-Lasers induced on the absorbers icroplasmas and resulting shock waves, which ultimately lead to an optomechanical destruction of the integrity of the fastening material. When incorporating an abovementioned photodegradable absorber in composite, the solution of the compound can be made by a photochemical process. The (laser) light irradiation can take place either simultaneously and over the entire surface via the connecting joint or sequentially in partial areas. The sequential irradiation can be done by manually moving or through

automatic scanning done.

The irradiation of the joint can be done either by means of a suitable applicator or by integration of the (laser) light source or the

Beam feed into suitable removal tool. At the

Irradiation is a homogeneous beam distribution of the irradiated (laser) light advantageous. But are also possible others, such as Gaussian

Beam profiles. In particular, if only a weakening of the connection point is desired, can also

Multifocal irradiation with a concentration of power to multiple Einstrahlpunkte done.

Depending on the application, complete destruction of the connection is not absolutely necessary. For one

The greatest possible protection is then only a weakening of the joint before the mechanical release of the

Compound, possibly using the known dental devices, sufficient.

In terms of the device, the invention provides for a base part, an attachment and a base part with the attachment firmly together

Connecting component existing component before that between the base part and the attachment part an adhesion-promoting release material is arranged, the under the influence of electromagnetic radiation his

adhesion-promoting effect reversible or irreversible loses.

It is advantageous in this case if the separating material on the connecting surface of the base part and / or the

Attached attachment to the connecting means and / or introduced into the connecting means.

Next, it is recommended that the electromagnetic

Radiation is in the range of visible light and in the adjacently adjacent frequency range.

To achieve an optimal effect, the beats

Invention before that the electromagnetic radiation consists of short, high-energy pulses.

For this purpose, it makes sense that the delivery of the

electromagnetic radiation a Q-switched

Nd: YAG laser is provided.

Furthermore, it has proved to be advantageous if the attachment part is transparent or at least less

Absorption for the electromagnetic radiation is.

It is further advantageous if the release agent has a high absorption compared to the electromagnetic

Having radiation.

A further advantageous embodiment is achieved when the release agent contains amorphous carbon.

In the context of the invention it is further proposed that the release agent as quantitatively reflected in the visible spectrum and absorbed in the near infrared. Accordingly, it is recommended that the release agent under optomechanical interaction undergoes a phase change with volume change and / or consistency change.

It is further considered advantageous when in the

Release agents under the influence of electromagnetic radiation microplasmas are triggered with consequent shock waves.

In this case, the reversible or irreversible loss of the adhesion-promoting action of the release agent can occur in a preferred action by the microplasmas or the shock waves.

In an advantageous application of the invention, the base part of a tooth, a ground tooth, an implant or the like and the attachment part of a crown, a bracket, a filling, a bridge, a veneer or the like may be formed.

Further details, advantages and features of the invention will become apparent not only from the claims but also from the following description of preferred

Embodiments.

Show it:

Fig. 1 shows an arrangement with reversible connection of a

Crown in which the absorber in the cement

mixed in, Figure 2 shows a possible form of sequential irradiation of the crown to dissolve the compound,

Fig. 3 shows an arrangement with reversible connection of a

Brackets on the tooth where the absorber is applied in a thin layer on the tooth and

Fig. 4 shows an arrangement with only partial disintegration of the connection in the edge region of the bracket.

In Fig. 1 is an example of a possible arrangement

shown, which shows a reversible attachment of a crown 1 on the tooth 2. The absorbers 3 are here

For example, soot particles that are mixed with the mounting material, which is located in the joint 4. The solution of the connection is made by

Irradiation with laser light 5, e.g. with laser light of the wavelength 1064 nm of a Q-switched Nd: YAG laser, through the crown 1 and leads to irreversible damage to the compound by selective light absorption 6 and by induced microplasmas in the

Joint.

Fig. 2 shows a possible form of sequential

Irradiation of the attachment point in subareas 7, wherein advantageously the individual subareas 7 can overlap. The arrows indicate a possible direction of movement of the manual or automatic

Scan on. In Fig. 3, an arrangement is shown by way of example, in which a bracket 8 is mounted on the tooth 2. The absorber 3 is here exemplarily layered on the tooth

applied. The irradiation to solve the attachment takes place laterally via a light guide 9 in the direction of the connecting joint.

FIG. 4 shows, by way of example, the region below the bracket 7 in which the

Connection is solved due to the lateral radiation, while in the central region 11, the attachment still exists. Thus, here is only a total weakening of the attachment.

Claims

Claims: Method for the reversible attachment of a

Attachment on a base part by means of a connecting means firmly connecting them together, characterized in that between the base part and the attachment part an adhesion-promoting

Separating material is arranged, which reversibly or irreversibly loses its adhesion-promoting effect under the influence of electromagnetic radiation.

The method of claim 1, wherein for the reversible attachment of the attachment forming part

dental restorations, fillings and / or brackets on the base part formed by a tooth, residual tooth, implant or the like, characterized in that in the connecting joint

light-absorbing material is introduced, which by irradiating irradiated

electromagnetic radiation of suitable wavelength leads to a disintegration of the compound.

A method according to claim 2, characterized in that the absorber is admixed to the usual dental fastening material.

A method according to claim 2, characterized in that the absorber is a specially developed

Fixing material is mixed.

A method according to claim 2, characterized in that the introduction of the absorber by applying an absorbent layer on the tooth and / or the dental restoration or the bracket.

Method according to claims 4 or 5, characterized in that the introduction of the absorber takes place in combination with a dental bonding system.

Method according to at least one of the preceding claims, characterized in that the

Wavelength range of the irradiation is chosen so that the highest possible absorption in the

Iichtabsorbierenden material is achieved.

Wavelength range of the irradiation is chosen so that the highest possible transparency for the medium to be irradiated, i. Tooth, dental

Restoration, filling or bracket is achieved.

Method according to at least one of the preceding claims, characterized in that the absorber is chosen so that it is not visible to any

Discoloration of the junction leads,

Method according to at least one of the preceding claims, characterized in that the absorber is chosen so that it is insensitive to normal environmental conditions, so that over time it does not lead to a deterioration of the composite.

11. The method according to at least one of the preceding claims, characterized in that nanoparticles are used as absorbers. 12. The method according to at least one of the preceding

Claims, characterized in that a

photodegradable absorber is integrated into the composite matrix. 13. The method according to at least one of the preceding

Claims, characterized in that the

Irradiation using pulsed lasers takes place. 14. Method according to at least one of the preceding

Claims, characterized in that the pulse duration of the laser is shorter than 1 ms.

15. The method according to at least one of the preceding

Claims, characterized in that the release of the

Connection by thermo-mechanical ablation takes place.

16. The method according to at least one of the preceding

Claims, characterized in that the release of the connection takes place by optomechanical interaction.

17. The method according to at least one of the preceding

Claims, characterized in that the dissolution of the compound takes place photochemically.

18. The method according to at least one of the preceding claims, characterized in that the

Irradiation via a simultaneous, full-surface irradiation of the joint is done.

19. Method according to at least one of the preceding

Claims, characterized in that the

Irradiation takes place sequentially in subareas. 20. Method according to at least one of the preceding

Claims, characterized in that the

Irradiation via a multifocal irradiation

he follows . 21. Method according to at least one of the preceding

Claims, characterized in that only a weakening of the connection is achieved by the irradiation.

Method according to at least one of the preceding claims, characterized in that the dissolution of the compound using the known

dental aids.

From a base part, a AufSatzteil and a the base part with the attachment part firmly interconnecting connecting means existing component for carrying out the method according to claims 1 to 22, characterized in that between the

Base part and the attachment part an adhesion-determining separating material is arranged, which reversibly or irreversibly loses its adhesion-promoting effect under the influence of electromagnetic radiation. Component according to Claim 23, characterized in that the separating material acts on the connecting surface of the

Base part and / or the attachment to the

Applied compound and / or in the

Connecting means is introduced.

Component according to claim 23 or 24, characterized

characterized in that the electromagnetic radiation is in the range of visible light as well as in adjacent adjacent frequency range.

Component according to one of Claims 22 to 25, characterized in that the electromagnetic radiation consists of short, high-energy pulses.

Component according to Claim 26, characterized in that a Q-switched Nd: YAG laser is provided for emitting the electromagnetic radiation.

Component according to one of claims 22 to 27, characterized in that the attachment part is transparent or at least of low absorption for the

electromagnetic radiation is.

Component according to one of claims 22 to 28, characterized in that the release agent has a high

Having absorption against the electromagnetic radiation. 30. Component according to one of claims 22 to 29, characterized in that the release agent amorphous

Contains carbon. Component according to one of Claims 22 to 30, characterized in that the release agent reflects as quantitatively as possible in the visible spectrum and absorbs it in the near infrared,

Component according to one of claims 22 to 31, characterized in that the release agent under

optomechanical interaction undergoes a phase change with volume change and / or KonsiStenzänderung.

Component according to one of claims 22 to 32, characterized in that microplasmas are triggered in the separating means under the influence of the electromagnetic radiation with consequent shock waves.

Component according to claim 33, characterized in that the reversible or irreversible loss of the microplasmas or the shock waves

adhesion-promoting effect of the release agent occurs.

Component according to one of claims 22 to 34, characterized in that the base part of a tooth, a ground tooth, an implant or the like and the Aufsatzteil of a crown, a bracket, a filling, a bridge, a

Veneering or the like is formed.