Patent Application
20150069690
The present invention relates to the use of at least one adjusting element for plane-parallel alignment of a first surface, in particular of a test body comprising a dentine and/or enamel surface, with respect to a contact surface and/or to at least one second surface, in particular with respect to a contact surface on which a self-adhesive dental material or a non-adhesive dental material in the form of a three-dimensional mold contacts a first surface, which is optionally coated with an adhesive dental material, as well as the use of the at least one adjusting element in a device, in particular in a device for producing an adhesive bond at the contact surface between the first surface and the at least one second surface, and a method for determining the force that needs to be applied to separate or break the adhesive bond, in particular in the form of a three-dimensional mold, at the force surface and/or contact surface between the first and the at least one second surface (
The adhesion to enamel and dentine is an important property of dental materials, in particular dental adhesives or self-adhesive dental materials or, if applicable, dental materials for modelling. The so-called shear bond strength test is used to measure how well a dental material or dental adhesive adheres to a tooth and/or a surface of a tooth. The method for determination of the shear bond strength is carried out according to DIN EN ISO 29022:2013 through embedding human or bovine teeth in dental hard plaster or acrylic resin, preferably in self-curing acrylic resins. The test bodies thus produced are then polished and processed further in accordance with DIN EN ISO 29022:2013.
The entire method, in particular in accordance with DIN EN ISO 29022:2013, can be subdivided into two procedural sections and/or two separate methods. In the first section, an adhesive bond is produced in a first device, and the adhesive bond is broken in a second device in a second section. Said method and/or both sections of the method are associated with multiple challenges. Firstly, a test body comprising the relevant surface for adhesion of a dental material, in particular of a tooth, needs to be produced. For this purpose, the tooth comprising the surface relevant for adhesion usually needs to be embedded into an acrylic resin and then this surface needs to be made accessible. For this purpose, the test body obtained after light-mediated or chemically mediated curing, which is usually cylindrical in shape, is polished to be flat in order to expose a sufficient surface area of the surface relevant for adhesion of a dental material, such as tooth substance, in particular enamel and dentine, for the test. Due to the shrinkage of the embedding material, such as acrylic resin, a test body with inclined surfaces and/or surfaces that are not plane-parallel with respect to each other, in particular upper sides and undersides, is obtained (
In a subsequent step, a dental material, in particular composite, such as self-adhesive dental material or non-adhesive dental material, or adhesive is filled into the sample well, which leads to leakage of dental material through the gap from the sample well and distortions when surfaces that are not plane-parallel are used in the device according to the prior art (
Another problem is the loss of material due to dental material leaking from the gap, which results in the need to use more material to fill the sample well. Moreover, the lengthy manual polishing of the test body into a plane-parallel geometry leads to a large loss of material. As a result, the total height of the test body is decreased strongly, which renders the clamping into the device for producing an adhesive bond between the first surface and a second surface, in particular in accordance with DIN EN ISO 29022:2013, no longer feasible. According to DIN EN ISO 29022:2013, it is permissible to compensate the height of the test body using up to 12 microscope slides in order to attain the required minimal height of 20 mm. In this context, the microscope slides are glued together with adhesive tape and are then positioned on the underside of the test body. This is cumbersome and leads to instability of the arrangement of stacked elements, such as slides, test body, and shaped part, in a device according to the prior art for producing the adhesive bond. It is a disadvantage of microscope slides that the compensation of height can only be done in steps equal to the thickness of the individual microscope slide, which ranges from 1.0 mm to 1.5 mm according to the prior art, e.g. in accordance with DIN ISO 8037-1. Regardless of which microscope slides are used, step-less or continuous height adjustment deviating from the thickness of the individual microscope slide, is not feasible. Another disadvantage of the microscope slides, which usually consist of glass, is their low breaking strength which can lead to breakage of the cover slides when the test body is clamped under a shaped part in the device up to the pressure required for frictional connection.
U.S. Pat. No. 6,324,916 B1 discusses the afore-mentioned challenges associated with the measurement of a shear bond strength and describes, for improvement of the accuracy of the measurement, a shearing device that exerts the shearing force by means of a shaped part for exertion of the shearing force via a minimal contact surface on a mold of a dental material. However, U.S. Pat. No. 6,324,916 B1 does not provide a solution for the generation of distortions and thus for the problem of the contact surface being ill-defined and the surface of the adhesive bond being falsified.
Therefore, the current method still is associated with significant disadvantages such as i), the time-consuming polishing of the test bodies, ii) the unattainable plane-parallel position of the tooth surface to be tested (enamel and dentine) of the test body, iii) the needed compensation by means of the easily breaking microscope slides facilitating a height compensation only, but not compensation of the inclined position of the test body, iv) and thus the generation of gaps between tooth surface and the device for producing an adhesive bond with the composite, v) consequently, the leakage of the dental material, in particular composite, and the ensuing loss of material, and vi) the formation of distortions and thus generation of a falsified surface area in the force measurement, which vii) causes falsified shear bond strength results and thus falsified bond strength results of the dental material on tooth surfaces.
It is therefore the object of the present invention to preclude the afore-mentioned disadvantages, in particular the formation of distortions, by optimizing a device and through the use of said device in a method for producing an adhesive bond between at least one dental material and a tooth surface in accordance with DIN EN ISO 29022:2013. It is an object of the present invention to provide a device that ensures a plane-parallel arrangement of a first surface of a test body, in particular of a dentine and/or enamel surface of a tooth, and a contact surface, at which at least one second surface, in particular a surface of an adhering dental material, such as an adhesive, self-adhesive dental material, such as a composite, or non-adhesive dental material, such as filling material, contacts the first surface. Moreover, the invention is to provide a device that prevents the formation of gaps upon the use of a shaped part between a first surface of a test body and a contact surface, in particular at least one second surface, and prevents the leakage of dental material from the shaped part and thus the formation of distortions. The specific object of the invention is to provide the use of a device, which, if the shaped part is used, does not comprise a gap between the lower sample opening and/or the lower edge of the shaped part and at least one first surface of a test body, optionally a first surface coated with an adhering dental material, such as adhesive, such that no dental material leaks between a first surface and the lower edge of the shaped part. Moreover, it is another object of the present invention to ensure a defined and reproducible contact surface between a first surface and at least one second surface, in particular in the form of a three-dimensional mold. It is another object to ensure a defined and reproducible adhesive surface of the adhesive bond between a first and at least one second surface that coincides with the contact surface and thus to provide a reproducible method for producing an adhesive bond with at least one defined adhesive surface and geometry as well as a reproducible method for determining the adhesive strength of a dental material on a tooth surface, in particular enamel and/or dentine, in particular a reproducible method for determining the shear bond strength in accordance with DIN EN ISO 29022:2013 with reproducible measuring results expressed as force per unit area.
The solution of the objects is described by means of the subject matters of the independent patent claims and, in actual embodiment, in the dependent claims and, in detail, in the description and the figures. The figures are schematic drawings that do not necessarily have to be true to scale and just show the essential components and the essential arrangement.
One subject matter of the present invention is the use of at least one adjusting element, as shown in
The device, in particular measuring facility, which preferably can also comprise a clamping device having at least one fixation element, in which a sample may need to be aligned, comprises all measuring facilities, in which a vertical impact is exerted on the sample and in which a non-plane-parallel surface and/or the angle between the surface to be tested and the source of said impact can affect the measuring results. Conceivable impacts include physical forces such as gravitation, electromagnetic interactions in the form of light, electricity, magnetism as well as thrust force, traction force, shearing force, and centrifugal forces. Such sensitive measuring facilities include, in particular, camera-coupled devices comprising microscopes, such as light microscopes, laser microscopes (LSM, CLSM), X-ray, ultrasound, magnetic resonance, and scanning microscopes (AFM, SFM and RKM), CCD camera-coupled devices, devices for measuring physical and physico-chemical interactions such as contact angle measurement. Accordingly, another subject matter of the present invention is the use of at least one adjusting element, as shown in
During the use according to the invention, the at least one adjusting element is being positioned at the underside of a test body, which concurrently is the side facing away from the first surface. As a result, the test body and/or the first surface are being aligned to be plane-parallel with respect to the source of the impact, in particular with respect to a shaped part.
During the use according to the invention, the alignment is done with at least one adjusting element, whereby a) the height of the adjusting element is continuously adjustable, in particular step-less, or in steps in a range of more than or equal to 0 mm, in particular to less than or equal to 100 mm, and/or b) the inclination of the adjusting element is continuously adjustable, in particular step-less, or in steps up to an angle alpha of more than or equal to 0 angular minutes, in particular up to less than or equal to 60° between a plane E and plane Ealpha of the adjusting element and the underside of the test body. Accordingly, (i) the height of the test body, in particular of the first surface, can be aligned by adjusting the height of the adjusting element while keeping the angle of the adjusting element constant, (ii) the inclination of the test body, in particular of the first surface, can be aligned by adjusting the angle of the adjusting element while keeping the height constant, or (iii) the height and the inclination of the test body, in particular of the first surface, can be aligned by adjusting both the height and the angle of the adjusting element.
The height of the adjusting element can be adjusted in a range from more than or equal to 0 mm, in particular to less than or equal to 100 mm, preferably in a range from more than or equal to 0 mm to less than or equal to 100 mm, from more than or equal to 4 mm to less than or equal to 100 mm, from more than or equal to 4 mm to less than or equal to 80 mm, from more than or equal to 4 mm to less than or equal to 70 mm, from more than or equal to 4 mm to less than or equal to 60 mm, from more than or equal to 4 mm to less than or equal to 50 mm, from more than or equal to 4 mm to less than or equal to 40 mm. The height can be adjusted in step-less manner or in steps, in particular in steps of 1 mm. The inclination of the adjusting element can be adjusted through variation of angle alpha between plane E and plane Ealpha, whereby plane E of the test body floor space corresponds to a position that is plane-parallel to the base, and plane Ealpha corresponds to the inclined test body floor space. The angle alpha can be adjusted in a range from more than or equal to 0′ angular minutes, in particular to less than or equal to 60° degrees, step-less or in steps. Preferably, in a range from more than or equal to 0° to less than or equal to 50°, from more than or equal to 0° to less than or equal to 45°, from more than or equal to 0° to less than or equal to 40°, from more than or equal to 0° to less than or equal to 35°, from more than or equal to 0° to less than or equal to 30°, particularly preferably from more than or equal to 0° to less than or equal to 25°. In particular, the angle alpha can be varied in small steps (1°=60′ angular minutes) of more than or equal to 0′, 6′, 12′, 24′, 30′, 36′, 42′, 48′, 54′, and to less than or equal to 60′ angular minutes and minute inclinations of less than or equal to 1° degree, preferably of less than or equal to 60′, 54′, 48′, 42′, 36′, 30′, 24′, 12′, to less than or equal to 6′ angular minutes can be fine-adjusted. In particular, step-wise adjustment of angle alpha in a range from more than or equal to 0° to less than or equal to 10° in angular minute [′] steps of 30′ is preferred. Preferably, the angle-adjustable component is a ball-shaped element and/or comprises a ball joint with three degrees of freedom.
In particular, step-less and/or continuous adjustment of the height and/or inclination of the adjusting element is another advantage of the use, according to the invention, of the adjusting element as compared to the use of cover glasses according to the prior art for adjusting the height, whereby the thickness of the cover glasses defines a step-wise adjustment. Using cover glasses as used according to the prior art, in particular in accordance with DIN EN ISO 29022, preferably DIN EN ISO 29022:2013, it is not possible to compensate the inclination of the tooth surface on which the adhesion of a dental material is to be tested. The use of the adjusting element according to the scope of the invention enables such compensation of the inclination and thus eliminates the main reason for the generation of distortions, namely gaps due to the first surface being in an inclined position. Specifically with oblique test body and/or test bodies whose surfaces are not plane-parallel, the use of cover glasses in the device for producing an adhesive bond according to the prior art does not allow tightness between first surface and lower edge of a shaped part to be attained. Consequently, this causes the lack of a defined and reproducible contact surface according to the prior art and therefore, ultimately, the falsified adhesive surface and the falsified measuring results in the determination of the adhesion and/or shear bond strength, in particular in accordance with DIN EN ISO 29022, preferably DIN EN ISO 29022:2013. Said disadvantages are eliminated through the use, according to the invention, of the adjusting element.
For this reason, another subject matter of the present invention is the device comprising the adjusting element as well as the use, according to the invention, of the adjusting element, as described above, whereby the second surface is a surface of at least one adhering dental material, self-adhesive dental material and/or non-adhesive dental material in the form of a three-dimensional mold. In particular, the mold has a three-dimensional geometry that corresponds to the negative shape of the sample well of a shaped part. Preferably, the geometry of the mold is adapted to a shaped part of a device in shape-matching manner and/or the shaped part is designed to match the geometry of the mold. Preferably, the mold has a cylindrical geometry.
The geometry of the mold is pre-defined, in particular, by the design of the sample well of a shaped part used to apply the material to be tested, presently at least one adhering dental material, self-adhesive dental material and/or non-adhesive dental material, onto the first surface. A sample well of this type and/or the internal wall and the lower edge of the sample well of a shaped part border(s) the area and/or region on the first surface that is covered by the dental material to be tested. Said bordered area corresponds to the contact surface (
Adhesion describes a complex process at the phase boundary of the materials involved in the process. Adhesion is understood to be the phenomenon resulting from interactions on the atomic and/or molecular level that is apparent as the resistance to a separating load acting on the composite.
In particular, the use, according to the invention, of the pre-scribed adjusting element, preferably in a device, involves that the shaped part is aligned such that at least one defined contact surface and thus at least one reproducible adhesive surface, for example of a non-adhesive dental material, such as a filling material, with respect to the adhesive (
A force-locked clamping of the test body, in particular through the use of a clamping device and at least one fixation element, can be additionally required for tightness along the lower edge, provided the plane-parallel alignment in the scope of the invention alone does not yet attain tightness. This is no problem at all if the adjusting element for adjusting the height and/or inclination is used, which is in contrast to the use of cover glasses according to the prior art and DIN EN ISO 29022, preferably DIN EN ISO 29022:2013. Due to the nature of the material of the adjusting element, made from steel, stainless steel and/or alloys thereof, force-locked clamping of the test body under the shaped part is feasible without affecting the adjusting element, test body and/or first surface. In contrast, the use of cover glasses does not provide for force-locked clamping and/or connection between the lower edge of the sample well and the first surface, because the breaking strength of glass is low. Glass breakage during the method for producing an adhesive bond can lead to a shift of the position, in particular, of the first surface in the device and can thus lead to the formation of gaps between a first surface and the lower edge of the sample well of the shaped part and thus to leakage of the dental material and the generation of distortions. Moreover, said glass breakage can also affect the formation of the adhesive bond, during which interactions between a dental material and the first surface on an atomic and/or molecular level proceed, in particular during the curing process, whereby chemical and physico-chemical bonds already formed might be severed again. Said connections in an adhesive bond and/or on an adhesive surface include, in particular, hydrogen bridge bonds and covalent bonds between the functional groups which are known to a person skilled in the art from the prior art. The use of the adjusting element precludes the adverse effect on the formation of interactions and bonds between a first surface and at least one second surface, in particular of a dental material. In particular upon formation of an adhesive bond, in particular in a three-dimensional mold, between an adhering dental material, such as an adhesive, and a tooth surface, such as enamel and/or dentine, between an adhering dental material and a non-adhesive dental material, such as filling/cement materials and composites, or between a self-adhesive dental material, such as a composite, and a tooth surface, such as enamel and/or dentine. Preferably, the adhesive bonds described above are present as three-dimensional cylindrical shapes (
Accordingly, another subject matter of the present invention is the use of an adjusting element in a device for producing at least one adhesive bond, in particular a device for producing an adhesive bond in accordance with DIN EN ISO 29022, preferably DIN EN ISO 29022:2013, on at least one contact surface (
Preferably, having the boundaries leads to a flush and gap-free closure between the lower edge and the first surface such that tightness is attained, which prevents leakage of dental materials from the lower sample opening.
Preferably, the sample well of the shaped part comprises a cylindrical or angular geometry, in particular made up of four rectangular areas. The geometry of the sample well determines the spatial shape of the mold. Accordingly, the mold in the scope of the invention comprises any three-dimensional shape that is feasible based on the design of the sample well and/or is matching in shape and/or is a negative shape of a shaped part of a device. Preferably, the mold is cylindrical in shape. Accordingly, the contact surface between the first surface and at least one second surface comprises corresponding two-dimensional dimensions also.
The three-dimensional test body comprises the sample to be tested and/or at least one material to be tested. In this context, the test body can fully consist of a sample of material to be tested or the sample of material to be tested is embedded in another material, in particular in a material that can be cured by means of light or can be chemically polymerized. Preferably, the sample of material to be tested comprises a first surface in the scope of the invention, on which the adhesion of a dental material is tested and on which an adhesive bond is formed for this purpose. Preferably, the sample of material to be tested is a tooth surface, in particular a human tooth surface, and the first surface is particularly preferred to be enamel and/or dentine.
Another subject matter of the invention is a use of the at least one adjusting element in a device for producing an adhesive bond, in particular a device for producing an adhesive bond in accordance with DIN EN ISO 29022, whereby at least one adhesive bond is formed on the at least one contact surface between
In an embodiment of the invention, the use according to the invention comprises at least one adhesive bond, according to an alternative (a), between the first surface and a second surface of a self-adhesive dental material in the form of a three-dimensional mold (
The at least one intermediate layer comprises at least one adhering dental material, which also include primers, self-etching primers, ceramic primers, metal primers, in particular light-curing primers. Said primers are needed, in particular, during the use of composite or cement materials, in particular non-adhesive materials, in order to attain good adhesion on a first surface, such as enamel and/or dentine. In a special embodiment, at least two intermediate layers are present, whereby the first intermediate layer contains a primer and the second intermediate layer contains an adhesive (bond). In particular, two intermediate layers are used for promotion of adhesion of a composite or cement material on a first surface. Said embodiment comprises, in particular, the arrangement of first surface/primer/adhering dental material (adhesive)/non-adhesive dental material.
Preferably, the first surface is present in the form of a test body. It is particularly preferred for the first surface to be an enamel and/or a dentine surface of a human or animal tooth, whereby same is embedded in a polymerizable material, preferably acrylate-based embedding material, with an embedding material approved in accordance with DIN EN ISO 29022 being particularly preferred. Referring to the human denture, the molar teeth (grinders) are preferred, the third molar is particularly preferred. Referring to the animal denture, preferably bovine denture, the incisor is preferred. The test body is produced according to the methods known according to the prior art, in particular the method described in DIN EN ISO 29022.
Another subject matter of the invention is a device (
In a special embodiment, the first surface, in particular the dentine and/or enamel surface of a tooth, is already coated with an adhering dental material, such as an adhesive described above. Accordingly, the application of an adhering dental material, in particular in the form of at least one intermediate layer, in the scope of the invention can proceed even before the introduction of the test body into the device as described. Alternatively, the application of the adhesive can also proceed after the test body having the first surface has been positioned in the device as described above.
The contact surface between the first surface and the second surface of the three-dimensional mold corresponds to the diameter of the three-dimensional mold (
The contact surface is defined by the surface which is bounded by an inner wall of a lower edge of a lower sample opening of a shaped part and by the first surface arranged below the lower edge of the shaped part (
Another subject matter of the invention is a device for producing at least one adhesive bond on at least one contact surface between a first surface, in particular of a test body, and at least one second surface, in particular of a mold comprising a dental material, preferably for producing an adhesive bond in accordance with DIN EN ISO 29022, comprising
In particular, the first surface or the contact surface can be aligned according to the opposite contact surface or first surface, in particular through the use of the device comprising an adjusting element and a shaped part. Accordingly, the first surface can be aligned according to the contact surface or the contact surface, in particular the shaped part, is aligned into a plane-parallel position with respect to the first surface. In the former case, the first surface is positioned, in detachable manner, or is affixed and/or installed on the adjusting element, as has already been described above, and in the latter case the shaped part is aligned with respect to the first surface by means of the adjusting element. In this context, the shaped part is installed fixedly on the test body floor space of the adjusting element, comprising at least one angle-adjustable component, and the adjusting element is clamped into a clamping device by means of at least one fixation device, whereby the lower sample opening of the sample well is aligned with respect to the first surface of a test body arranged below the sample well. Optionally, an adjusting element having at least one height-adjustable component can be arranged below the test body in order to overcome a potential height difference. This also provides for a plane-parallel position of the first surface with respect to the lower edge of the shaped part such that a defined and reproducible contact surface and thus a defined and reproducible adhesive surface in the adhesive bond are attained, as before. Accordingly, when the dental material, in particular an adhering, self-adhesive or non-adhesive dental material, is introduced into the sample well of the shaped part, there is no leakage of material, since there is no gap between first surface and the lower edge of the shaped part, in particular the contact surface. This ensures a reproducible measurement of the force per unit area, which is identical to the contact surface of the tested adhesive bond as obtained according to an alternative (a) or (b) as shown in
Another subject matter of the present invention is a shaped part that surrounds a test body in shape-matching manner (see
Using a shaped part of any of the types described above precludes the formation of gaps between a first surface and the lower edge of a shaped part. Due to the fit being flush and preferably tight, a defined and reproducible contact surface is attained, such that no not-yet-cured dental material leaks from the sample well and the formation of distortions is precluded. By this means, defined and reproducible adhesive surfaces in the adhesive bond are always obtained and thus a reproducible determination of the adhesion of a dental material on a first surface is attained, preferably on a tooth surface comprising enamel and/or dentine, preferably by measurement of the shear bond strength, in particular in accordance with DIN EN ISO 29022. This allows reproducible and reliable information about the bond strength of an adhering dental material or self-adhesive dental material to be obtained. Concurrently, since distortions are precluded and there is no polishing process as required according to the prior art, materials and costs are saved in the method.
As a further subject matter of the present invention, a preferred embodiment of the device described above comprises at least one adjusting element having the following components (see
Preferably, the adjusting element comprises a height-adjustable component and an angle-adjustable component, preferably a ball-shaped element. Preferably, the test body floor space has a circular geometry and a diameter designed appropriately such that the test body can be set up securely without tipping. Preferably, the entire underside of the test body stands on the test body floor space, as is shown in
In a preferred embodiment, the device described above comprises at least one adjusting element that is attached in non-detachable manner on a working surface, in particular through its base on the floor space of a clamping device, preferably by means of at least one fixation element, or is positioned in detachable manner on a working surface of a device or measuring facility (
Preferably, the underside of the test body contacts the test body floor space of the adjusting element in the device according to the invention, preferably in a device for producing an adhesive bond between a first surface, in particular a tooth surface comprising enamel and/or dentine, in particular in a device in accordance with DIN EN ISO 29022.
Preferably, the device according to the invention, in particular in accordance with DIN EN ISO 29022, comprises a clamping facility having at least one fixation element, preferably screws and/or nuts, for fixing test body between the at least one adjusting element and the shaped part and/or an adjusting element having at least one locking device for fixing the adjusting element on the floor space.
In a preferred embodiment of the device according to the invention for producing an adhesive bond between a first surface, in particular a tooth surface comprising enamel and/or dentine, in particular in a device in accordance with DIN EN ISO 29022, the adjusting element is not detachable. In particular, the adjusting element, which is situated on the floor space of the clamping device in non-detachable manner and/or is positioned on its base in detachable manner, preferably locked by means of at least one locking device, and the test body, which contacts the test body floor space of the adjusting element through its underside, is not detachable for the duration of a method for producing at least one adhesive bond, in particular not during the curing process of a dental material, in particular not during the polymerization of a dental material and adhesion of the dental material to the first surface. Preferably, the device as described above is not detachable for the duration of the curing, in particular during the polymerization of the adhering dental material and adhesion of the material to the first surface in a device and a method in accordance with DIN EN ISO 29022. If the afore-described arrangement is connected in force-locked manner, shocks cannot have an adverse effect on the process of adhesion due to shifts of the individual elements of the device. As a result, reproducible adhesive surfaces are attained, which preferably coincide with the contact surface between a first surface and at least one second surface comprising the at least one dental material.
A reproducible adhesive bond produced as described above through the use of an adjusting element in a device has a positive effect on the second part of the whole method, as described above. The second part of the method relates to the measurement of the adhesion and/or shear bond strength. A device for exertion of a traction force, thrust force and/or shearing force is used in said methods and comprises a force-exerting shaped part that borders the three-dimensional mold along the longitudinal axis M (see
Another subject matter of the present invention is a method for producing at least one adhesive bond on a contact surface, in particular on a defined and reproducible contact surface, between a first surface, in particular of a test body, and at least one second surface, in particular of a mold, in particular a method for producing at least one adhesive bond in accordance with DIN EN ISO 29022, preferably DIN EN ISO 29022:2013, comprising the steps of
Alternatively, step c) can precede step b), whereby, if an oblique and/or inclined position is present, an alignment of the first surface into a plane-parallel position with respect to the contact surface and at an angle beta of 90° with respect to the inner wall of a sample well of the shaped part is done until the first surface is flush with the lower edge of the lower sample opening of the shaped part.
In a preferred embodiment of the method, the alignment (b) of the first surface of the test body is done according to the invention through at least one adjusting element through adjusting the height and/or inclination of the adjusting element with respect to the contact surface and the lower edge of the shaped part into a plane-parallel arrangement of the surfaces with respect to each other and at an angle beta of 90° with respect to the inner wall of the sample well, whereby
The shaped part can be attached in the clamping device in the method either before or after b) alignment of the first surface of a test body. In an embodiment of the method in the scope of the invention, the shaped part is applied onto the test body before or after b) alignment of the first surface, whereby the shaped part is designed appropriately such that the outer edge has an inner diameter that corresponds to the outer diameter of the test body, and the test body is surrounded by the outer edge at the outer wall in flush manner (see
In a special refinement of the method, c) a defined contact surface (
Optionally, the first surface is already coated with an adhering dental material, before applying a non-adhesive dental material. Moreover, a completely closed-off contact surface is thus obtained, whereby the lower edge resists on the test body by its entire circumference and thus prevents a dental material from leaking. As a result, the formation of distortions is precluded and, ultimately, reproducible measuring values in force per unit area, being equal to the adhesive surface, are obtained in a method for determination of the adhesion of at least one dental material, in particular of the shear bond strength in accordance with DIN EN ISO 29022.
Thus another subject matter of the invention is an adhesive bond between the first surface and the second surface, as both described herein, having a defined contact surface as described above and obtainable by the herein described.
Preferably, prior to d) the introduction of a dental material, the arrangement described above, as shown in
Steps d), e), and f) vary as a function of the desired arrangement (
In order to obtain an adhesive bond according to an alternative (a) (see
In order to obtain an adhesive bond according to an alternative (b) (see
It is preferred in the method according to the invention to have, in step d), the contact surface thus obtained be covered, preferably fully, at least by the dental material and to have the sample well filled with the dental material, in particular the self-adhesive or non-adhesive dental material, maximally up to the upper edge. A defined amount of the dental material is introduced in this context, whereby the consumed amount is reproducible since no dental material can leak as there are no gaps between the lower edge and the first surface. The method according to the invention attains not only at least one reproducible adhesive surface and thus a reproducible measurement of the force per unit area of the adhesive bond according to alternative (a) or (b), but also a significantly reduced consumption of material. Moreover, the method according to the invention affords a definition of the requisite volume of the dental material used in the individual case as a function of the size and volume of a sample well of a shaped part. This enables a reliable calculation of the costs of the method and easy implementation of the method.
According to the invention, e) an adhesive bond, in particular according to alternative (a) or (b) is formed in the method essentially at the contact surface, and a three-dimensional mold is obtained after curing, preferably light-mediated polymerization, of the dental material and removal of the shaped part (
Therefore, another subject matter of the invention is a method for determining the adhesive strength of at least one dental material on a first surface in an adhesive bond, in particular an adhesive bond according to an alternative (a) or (b), whereby said adhesive bond is present at the contact surface between the first surface and at least one second surface and the contact surface corresponds to the surface, which has a lower edge of the lower sample opening, an inner wall of a sample well of a shaped part, and the first surface, which is arranged below the lower edge of the shaped part, for its boundaries (
It is preferable in the method described above that a) the shaped part surrounds the three-dimensional mold along its longitudinal axis at least partially in shape-matching manner without directly contacting the outer surface, and that b) the force is exerted essentially through the shaped part at a minimal force surface and/or contact surface at the outer surface of the mold, whereby the shaped part touches the mold only at said contact surface as close as possible to the contact surface, preferably directly at the contact surface, and that c) the bond strength of the adhesive bond, in particular according to an alternative (a) or (b), is measured in units of force per contact surface area, as described above.
In the method for determining the bond strength of at least one dental material at a first surface, preferably a method for measuring the shear bond strength and/or bond strength in accordance with DIN EN ISO 29022, preferably DIN EN ISO 29022:2013, the adhesion in at least one adhesive bond, in particular according to an alternative (a) or (b), between a first surface and at least one second surface or in an adhesive bond between a first surface and an intermediate layer and an intermediate layer and at least one second surface is tested, whereby
Another subject matter of the present invention is a method for producing an adhesive bond and a method for determining the shear bond strength, each in accordance with DIN EN ISO 29022, in compliance with the standards defined therein.
Another subject matter of the invention is the use of the device according to the invention for producing at least one adhesive bond at at least one contact surface between a first surface and at least one second surface, comprising a dental material, for producing a three-dimensional mold comprising at least one adhesive bond between a first surface and at least one second surface, for producing an adhesive bond in accordance with DIN EN ISO 29022, for producing a three-dimensional mold comprising at least one adhesive bond in accordance with DIN EN ISO 29022, for producing an adhesive bond for use in a method for determining the force to be exerted to separate or break the at least one adhesive bond, and the use of an adhesive bond according to the invention, in particular according to an alternative (a) or (b), in a method for measuring the bond strength of an adhering dental material or of a self-adhesive dental material on a first surface, in particular dentine or enamel, and in a method for determining the shear bond strength in accordance with DIN EN ISO 29022.
The figures show schematic views of the invention and illustrate them in more detail without limiting the invention to the views presented in the figures.
a) to 5g) illustrates an adjusting element 10 and embodiments of the adjusting element 10
a) shows a cross-section of an adjusting element 10 having a test body floor space 14, an angle-adjustable component 13 as ball-shaped compensation element 13 and a base 11; the adjustable angle alpha between virtual plane E and plane Ealpha and the height shift resulting from angle alpha are indicated by arrows.
b) shows a cross-section of an adjusting element 10 having a test body floor space 14, an upper angle-adjustable component 13 and a height-adjustable component 12 arranged below it on a base 11; the adjustable angle alpha at plane E and the lowest height H as well as the maximal height Hmax of the height-adjustable component 12 are indicated by arrows.
c) shows a cross-section of an adjusting element 10 having a test body floor space 14 and a height-adjustable component 12 on a base 11; both the lowest height (H) as well as the maximal height (Hmax) are shown.
d) shows a top view of a test body floor space 14 of an adjusting element 10 having an outer diameter DA.
e) shows a cross-section of an adjusting element 10 having a ball-shaped compensating element for the angle-adjustable component 13 and at least one fixation element 16 for attaching an adjusting element 10 in/on a device for producing an adhesive bond 20 and/or clamping device 30; the adjusting element is positioned, by its base 11 and the at least one fixation element, on a floor space 32 of a device 20 for producing an adhesive bond and/or clamping device 30.
f) shows a cross-section of an adjusting element 10 having a test body floor space 14, a height-adjustable component 12 as well as at least one outer locking device 15 for fixation of the adjusted height of the adjusting element 10; both the lowest height (H) as well as the maximal height (Hmax) are shown.
g) shows a cross-section of an arrangement comprising a test body 60, which is positioned, by its underside 62, on the test body floor space 14 of an adjusting element 10, whereby the inclination of the test body 60 along a plane E is compensated through the angle-adjustable component 13 through an angle alpha, and a height-adjustable component 12 that is arranged below the angle-adjustable component 13 as well as at least one outer locking device for fixation of the adjusted angle and height of the adjusting element 10, whereby the adjusting element 10 is positioned, by its base 11, on a working surface 32 of a device 20 for producing an adhesive bond and/or clamping device 31.
a shows a detailed cross-section of a shaped part 40 arranged above a test body 60, comprising a sample well 46 for accommodation of a dental material 70 via the upper sample opening 43, having an inner wall 45 and a lower sample opening 41, that is distinct from the lower edge 42 as well as an outer edge 44 of the shaped part 40; upon the use of said shaped part, the lower edge 42 contacts the first surface 61 of a test body 60 and the outer edge 44 rests on the test body 60 within the diameter of the test body 60, in particular on the embedding material 67.
b shows a detailed cross-section of a shaped part 40 as in
c shows a detailed cross-section of a shaped part 40, as shown in
a shows a perspective view of an adhesive bond according to an alternative (a), in which the three-dimensional mold 71 comprises an adhering dental material 70 or a self-adhesive dental material 70 that forms, at the contact surface 21, the at least one second surface 72, which contacts the first surface 61, in particular enamel and/or dentine. After curing of the adhesive dental material or self-adhesive dental material 70, no distortions are present in the adhesive bond according to the invention.
b shows a perspective view of an adhesive bond according to an alternative (b), in which the three-dimensional mold 71 comprises a non-adhesive dental material 70 and an intermediate layer 90, whereby the intermediate layer 90 contacts the first surface 61 at the contact surface 21 and is connected to the at least second surface 72 of a non-adhesive dental material at its surface that faces away from the contact surface 21. In this embodiment, the adhering dental material 70 was introduced into the shaped part 40 after alignment of the test body in the device 20 and thus the intermediate layer coincides with the contact surface 21. After curing of the adhering dental material and non-adhesive dental material 70, no distortions are present in the adhesive bond according to the invention.
c corresponds to
a) shows a test body 60 that comprises an oblique underside 62.
b) shows a perspective side view of a device for producing an adhesive bond according to the prior art, in which, after fixation of the non-plane-parallel test body 60, a gap 80 arises between the first surface 61 of a test body 60 and the lower edge 42 of the sample well 46 of a shaped part 40.
c) shows a test body 60 having an oblique underside 62 aligned according to the invention such as to be plane-parallel, positioned on the test body floor space 14 of an adjusting element 10, whereby the first surface 61 is aligned to be plane-parallel with respect to the lower edge 42 and the outer edge 44 and contacts the shaped part such as to be flush without a gap existing between the lower sample opening 41 and the first surface 61.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2013 109 811.8 | Sep 2013 | DE | national |
