DE102022128589A1 - Abutment for a dental implant system and dental implant system with such an abutment - Google Patents

Abstract

Abutment part (1) for use in a dental implant system (60), with an abutment body (10) which has a connecting pin (4) which can be inserted into a corresponding receiving channel (64) of a post part (62) and which tapers continuously at least in sections towards its distal end (6), is intended to enable a particularly reliable and break-proof provision of the implant even when ceramic base materials are used. For this purpose, the abutment part (1) is designed in two or more parts according to the invention and, in addition to the abutment body (10), comprises an index element (12) which is arranged in a rotationally secure manner on the distal end of the connecting pin (4) and is made of a material which has an E-modulus of at most 60% of the E-modulus of the material forming the abutment body (10).

Description

The invention relates to a structural part for a dental implant system with an abutment body which has a connecting pin which can be inserted into a corresponding receiving channel of a post part and which tapers continuously at least in sections towards its distal end. It also relates to a dental implant system with a post part which can be screwed into the jawbone of a patient and with such a structural part.

Dental prosthetic systems can be used as part of reconstructive therapy to compensate for the loss of a tooth. Such a prosthetic system usually includes a dental implant, which is usually inserted into the jawbone in place of an extracted or lost tooth. After a healing phase of around four to twelve weeks, a prosthetic part or a crown serving as a tooth replacement is then placed on the dental implant as a prosthetic construction and fixed there. For this purpose, such a dental implant is usually designed as a suitably shaped metal or ceramic body that is screwed into the intended place in the jawbone. The dental implant usually has a mostly self-tapping screw thread at the apical end, with which the dental implant is inserted into the appropriately prepared implant bed.

In contrast to one-piece dental implants, in which the prosthetics serving as a tooth replacement are attached directly to the metal body screwed into the jawbone, two- or multi-piece implant systems are also known and widely used. In such a multi-piece dental implant system, in addition to the actual dental implant, also known as the "post part", which is screwed into the patient's jawbone, a so-called superstructure part or abutment is provided in the form of a connecting or transition piece, which carries the prosthetics or crown intended as a tooth replacement. After the actual dental implant has healed in the patient's jawbone, the abutment with the prosthetics is placed on the dental implant and connected to it, completing the dental prosthetic system.

Such a connection between the abutment intended for attaching the prosthetics and the inserted dental implant is usually made using a screw connection. To ensure that the overall system has sufficient mechanical stability with regard to the expected chewing loads, the abutment is usually provided with a connecting pin that can be inserted into an associated receiving channel in the dental implant in the manner of a plug connection and, when assembled, ensures lateral and, if necessary, axial guidance and fixed positioning of the components relative to one another. A screw channel for a connecting screw intended for connecting the abutment to the dental implant is usually integrated into this connecting pin. The connecting screw penetrates the screw channel and its external thread engages a corresponding internal thread in the dental implant. The screw head of the connecting screw rests on a countersunk face in the abutment located outside the screw channel and presses the abutment part onto the post part via this when the connecting screw is screwed in.

Currently, dental implants or implant systems are usually made of titanium or a titanium alloy and are designed as two-part implants of the type described above. This means that the implant body is osseointegrated in the jawbone and an abutment is mounted on this, to which the final prosthetics can be fixed. In order not to lose the rotational position when transferring the patient situation to a physical or virtual model, most implant-abutment connections are provided with a rotational locking mechanism, which is referred to as an index. This index can be clearly designed or have any number of positioning options for the abutment in the implant body. There are also variants that do not have an index. However, there are usually two to six positioning options, preferably three or four.

In recent years, the number of implants that are no longer made of metal such as titanium, but are metal-free, has increased significantly. There is a need for metal-free treatments or treatments that do not allow any metallic elements to come into contact with human tissue or saliva. If an implant-structure connection is to be designed to be tight, a metallic connecting screw between the implant body and the structure is usually accepted.

The metallic materials were mostly replaced by ceramics, especially zirconium oxide ceramics, aluminum oxide or yttrium-reinforced zirconium oxide ceramics or mixed ceramics or ceramic mixtures with a high proportion of zirconium oxide and/or aluminum oxide.

The first ceramic implants were designed as a single piece and then provided with a cemented or glued implant-structure connection in the second step. However, there are now also various variants with screwed implant-structure connections. It has been found that the comparatively delicate manufacturing, which is possible with metallic implants made of titanium or titanium alloys, is also necessary for reasons of space when installing them in the jaw area. However, with the ceramic implants known to date, such delicate manufacturing with a correspondingly small space requirement is hardly feasible due to the material properties of the ceramic. This means that the space requirement for corresponding connections with sufficient mechanical strength is hardly achievable.

The difficulty lies in the fact that connections between ceramic components mainly have point-by-point contact due to the relatively rough surface and the lack of deformability and flowability of ceramic materials, and only very rarely do they have the flat contact surfaces that are actually required to transfer relatively large forces between the components. This is mainly because metals can deform plastically at room temperature and ceramics cannot.

In the print WO 2012/065718 A1 A method is disclosed in which a softer but very well-adhering plastic layer is applied to the conical area of the abutment that transmits force between the implant body and the abutment. This ensures that the surface roughness and unevenness are evened out and that the force is transmitted across the surface between the implant body and the abutment. Using this technology, the strength of conical and fully ceramic implant-abutment connections with a metal connecting screw could be increased significantly, as this layer compensates for the corresponding manufacturing tolerances and roughness and avoids point contact between the components.

In the further course of such developments, various index variants were also designed for such fully ceramic implant-abutment connections. It was noticed that the components, in particular the post part, had to be designed with extremely thin walls due to the usually conical shape of the connection and the necessary length of the cones. Since an index is a geometric change to the cone and this is also usually designed with parallel walls, it is no longer possible to provide a uniform contact surface or force or torque transmission surface despite a thin plastic coating. This means that although the cone, which transmits the largest proportion of the force and torque, is in flat contact and not in a point-like manner, this cannot be achieved for the index, which is usually positioned underneath it. The consequence of the usually extremely limited space available there is that, despite the plastic coating of the index, point-like contact occurs between the implant body and the abutment part in the index area. The consequence of this is that fractures can occur in the contact areas, which can easily branch out and spread, particularly in ceramic components, due to the brittleness of the material. It was shown that these fractures usually start in the index areas of the abutment parts, but then spread further and grow into the cone area of the abutment parts. As a result, fractures of the entire abutment parts occurred, which led to a complete failure of the implant-abutment connection.

The invention is therefore based on the object of providing a structural part of the above-mentioned type which, despite the difficulties mentioned, has a particularly high mechanical stability even when only very little space is available at the place of use. Furthermore, a dental implant with such a structural part is to be specified.

With regard to the abutment part, this object is achieved according to the invention with an abutment or abutment part which is itself made up of several, preferably two, parts and which, in addition to the actual abutment body or first abutment part, has as a second abutment part an index element arranged at the distal end on the connecting pin of the abutment body in a rotationally secure manner and made of a material which has an E-modulus of at most 60% of the E-modulus of the material forming the abutment body.

The invention is based on the idea that in order to overcome the problems mentioned above when choosing comparatively brittle materials such as ceramic for the abutment part, the latter should have an index or indexing area with which, if index fractures occur, their spread into the conical area of the abutment part is consistently avoided. To this end, the index or indexing area should be designed as an independent second component, designed differently from the actual abutment body in terms of material, which can be attached to the cone of the first abutment section or "actual" abutment part. To avoid cracks forming in the contact area between the index part and the "actual" abutment part, the index part should be made of a material that can plastically deform at room temperature. In addition, the design should be chosen in such a way that the plastic deformation of the material occurs before a fracture can even occur in the ceramic fixation area of the abutment part. This can prevent the formation of fractures in themselves.

Such a multi-component design of the abutment part can in particular provide for a consistent functional separation of the two components from one another, with the actual abutment body, as the first abutment section, being specifically designed and constructed to absorb and transmit comparatively large forces, such as chewing forces. The second abutment section, i.e. the index element, is not designed to subsequently transmit larger forces and can therefore also be dimensioned weaker. Rather, it serves to correctly guide the components in rotation during assembly, during which the aim is to achieve a correct rotational alignment of the abutment relative to the post part when the connecting pin is inserted into the corresponding receiving channel provided in the post part. This can be reliably achieved without the index element having to be designed to be particularly resistant to external forces. For this purpose, the index element preferably has a suitably selected index, for example by selecting a suitably selected outer contour or a suitably selected outer cross-section, for example in the form of a hexagon, an oval or trioval, suitably selected outer projections or any other non-round shape suitable for indexing, which corresponds to an associated inner indexing in the receiving channel of the post part.

In view of these functionally different design goals for the components, these are also suitably dimensioned with regard to their geometric parameters according to an aspect of the invention that is considered to be independently inventive. In particular, it can be provided that the index element is attached right at the distal end of the abutment body; according to one aspect of the invention, the index element also has a length of at most 25%, preferably at most 20%, very particularly preferably 15% of the total length of the attachment part in the longitudinal direction of the system. According to one aspect of the invention, the length ratio between the index element provided for indexing on the one hand and the connecting pin, which is in particular conical and is provided for the transmission of forces and moments, is suitably selected; according to one aspect of the invention, the index element has a length of at most 50%, preferably at most 33%, of the length of the connecting pin.

The design objective mentioned can also or alternatively be achieved in principle with a large number of possible parameter combinations, particularly with regard to the dependence on the actual and corresponding, in particular geometric, design of the connection between the structural part and the index part. In accordance with the above considerations, according to one aspect of the invention, the two parts forming the structural part are suitably designed, in particular with regard to the choice of their E-modules relative to one another.

The abutment body is advantageously made of a ceramic material, because the multi-part design provided makes it possible to overcome the obstacles to using ceramic materials in dental implants. The abutment body preferably consists of a zirconium oxide ceramic, an aluminum oxide-reinforced zirconium oxide ceramic or a mixed ceramic or a ceramic mixture with a high proportion of zirconium oxide and/or aluminum oxide. The abutment body is particularly preferably made of a material with an elastic modulus of at least 180 GPa, preferably of at least 200 GPa.

For the index element as the second component, metals such as titanium, zirconium, tantalum and alloys with one of these metals as the main component are generally preferred, especially when using ceramic as the material for the abutment body. The reason for this is not only the ability of these metals to be plastically deformable, but also their ability to bend at lower mechanical stresses. Stresses and elastic deformation. This property is expressed in the characteristic value of the modulus of elasticity. The metals mentioned have in particular an modulus of elasticity of less than 60% of the modulus of elasticity of zirconium oxide ceramics and are therefore particularly suitable for material pairing with these ceramics in the sense of the present invention. In comparison to the aluminum oxide ceramics, aluminum oxide-reinforced zirconium oxide ceramics, mixed ceramics made of zirconium oxide and aluminum oxide or mixtures of zirconium oxide and aluminum oxide that are usually used in industry and are now preferred for the abutment body, the modulus of elasticity of these metals is only about 50% of that of the abutment body.

However, with such a design, i.e. a combination of a first structural part made of one of the ceramics mentioned with a second structural part made of one of the metals mentioned, which is considered to be independently inventive, not all fractures could be avoided. The reason for this is the relatively high strength of these metals. The fractures were observed in particular when using the metal alloys described. These have a higher elastic limit with a lower yield strength.

In order to further prevent the fracture from spreading to the first structural part, it has proven to be particularly preferred and independently inventive to further reduce the modulus of elasticity of the index body or second structural part compared to the first structural part and also to significantly reduce the strength of the index body or second structural part. To make this possible, the index element provided as the second structural part of the structural part is made from a plastic, preferably PPS, fiber-reinforced PPS, PEEK or fiber-reinforced PEEK, according to one aspect of the invention. Particularly preferred and in an embodiment considered to be independently inventive, the index element is made from a material with an modulus of elasticity of at most 120 GPa, preferably at most 80 GPa, particularly preferably at most 10 GPa.

With regard to the particularly preferred materials for the abutment body on the one hand and the index element on the other, the following E-modulus values are assumed: ZrO ₂ : 210 GPa, Ti: 105 GPa, PEEK (fiber-reinforced, e.g. available from Ensinger under TEKATEC PEEK): 59 GPa, PEEK (nominal): 4.2 GPa, PPS: 4.1 GPa, PPS (fiber-reinforced): 6.0 - 8.5 GPa.

In order to be able to effectively use the advantages of the abutment with abutment body and index element, which is designed in two parts according to one aspect of the invention, these should be mechanically connected to one another in the sense of pre-assembly. Due to the two-part or possibly multi-part design of the abutment with the abutment body as the first structural part and the index element or index part as the second structural part, there is a desire for a possibility of pre-assembly in which the index element can be attached to the abutment body in such a way that the ensemble pre-assembled in this way can be pushed as a whole into the receiving channel of the post part. The index element can thus bring about the correct rotational alignment of the abutment body relative to the post part when the connecting pin is pushed into the receiving channel. In a particularly preferred variant, it can be provided that this connection between the abutment body and index element is a detachable connection, whereby the only decisive factor is that the abutment part remains non-destructive. This is important because the prosthetics are anchored to it and the abutment part is the significantly more cost-intensive part of the abutment as a whole.

For example, there is a risk that a dental technician or dentist could accidentally destroy the index part when handling the components. In such a case, it is important that the index part can be replaced or exchanged quickly and easily. The connection between the abutment body and the index element is therefore preferably not based on bonding or cementing or any other material-locking or permanent connection, but is designed as a purely mechanical connection, for example in the form of a snap-in connection. This has the advantage that if the index element needs to be replaced, there are no adhesive or cement residues left on the abutment part that need to be removed, which could be laborious to remove.

• Das Ineinandergreifen von Abutmentkörper einerseits und Indexelement andererseits, und insbesondere das indizierte Ineinandergreifen, erfolgt rein oder vornehmlich radial, wie bei einer klassischen Inbusschraube und einem Inbusschlüssel. D. h. es befinden sich in einem radial geschlossenen Rohr (z. B. einem Inbusschraubenkopf in einer zentralen Formausnehmung (z. B. einer Bohrung) zu dieser ersten Formausnehmung radiale Formausnehmungen, welche es einer in der Form an diese Matrize angepassten Patrize eine Drehung des Matrizen-Patrizen-Systems zueinander nicht oder nur in einem sehr beschränkten Winkel (z. B. 10°) erlauben. Eine solches Rotationsgesperre zeichnet sich dadurch aus, dass sowohl die Matrize als auch die Patrize radial geschlossene Bauteile sind.

With regard to the connection mechanism between the abutment body and the index element, according to further aspects of the invention, the following basic design options for a corresponding coupling system can be provided:

• The interlocking of the abutment body on the one hand and the index element on the other hand, and in particular the indexed interlocking, takes place purely or primarily radially, as with a classic Allen screw and an Allen key. This means that there are in a radially closed tube (e.g. an Allen screw head in a central mold recess (e.g. a bore) to this first Form recess Radial form recesses which do not allow a male part, which is adapted to the shape of this female part, to rotate the female-male part system relative to each other or only to do so at a very limited angle (e.g. 10°). Such a rotation locking mechanism is characterized by the fact that both the female part and the male part are radially closed components.

An alternative, particularly preferred option for designing a coupling system according to one aspect of the invention is that a rotational locking mechanism is created between the abutment body and the index element by means of a number of axially aligned finger-like pins arranged off-center on one of the components in relation to the longitudinal axis of the system, which engage in the axial direction in associated mold recesses in the other component, such as in a claw coupling. Such a variant is preferred according to one aspect of the invention as a basic principle for the design of the coupling system. An important aspect here is that in such a system, which is open to the outside in the claw area, a particularly large proportion of the cross-section can be used to transmit torque in the direction of rotation; in this sense, there are no areas that cannot be used for torque transmission due to encapsulation or the like.

According to an alternative aspect of the invention, a combination of these approaches can also be provided for securing the abutment body against rotation and thus indexing it relative to the index element. This means that, for example, a number of closed mold recesses (matrices, e.g. round holes) are arranged on the front side of a tubular element in the manner of a pin coupling, into each of which a pin or rod element of the other component engages (in the manner of an associated male part). However, with this design, a certain proportion of the wall thickness of the system cannot be used for torque transmission due to the closed contours of the mold recesses.

When dimensioning ceramic components, such as the abutment body, it is usually essential for reasons of strength to avoid stress peaks in the ceramic body and to make the wall thicknesses sufficiently large, and even as large as possible given the extremely limited space available in implant systems. Based on the design variants of the index between the abutment part and index part described above and based on the same space requirement, it has been shown that the design of a purely axially interlocking rotational locking mechanism, similar to a claw coupling, enables the greatest wall thicknesses, especially in the abutment body. For this reason, in terms of preventing fractures in the abutment part, the design for the coupling system designed as a connection index between the abutment body and index element as such a rotational locking mechanism is particularly advantageous.

For reasons of simplicity, the implementation of a design similar to a claw coupling for the coupling system between the abutment part and the index part should advantageously be designed in such a way that, in addition to the rotational position fixation after the components have been connected, i.e. after the finger-like pins or pegs have been inserted or pushed into the associated mold recesses, the two components can no longer be easily separated from one another, in particular without targeted action by the user. For this purpose, according to one aspect of the invention, the pins in combination with the associated mold recesses are designed as locking or snap connections. With such a design, individual areas of the index part are elastically loaded during joining/fixing and usually up to just before or beyond the elastic limit, which reset after the fixing process and form a retention through a corresponding form fit, which prevents the components from separating. The pins are preferably provided on the index element, whereas the associated mold recesses are incorporated into a contact area of the abutment body.

In such a design as a snap lock or snap connection, the molded recess advantageously arranged in the abutment body preferably has a widening from the apical direction towards the occlusal direction, which tapers again towards the distal end and thus forms an undercut or retention for the adapted shaped pin or peg on the index element. In a preferred variant, the molded recess is initially designed in the form of a funnel from the apical direction towards the distal end in order to simplify centering before insertion. In addition to optimized insertion, this also results in optimized strength for the index part. This means that when subjected to a torque load, the index part is not loaded at the thinnest point, but in the area of a widening of the pin or peg on the index element.

According to an alternative aspect of the invention, the design can also be reversed. This means that the pins or pegs are arranged on the abutment body, whereas the associated ten shaped recesses are provided in an end contact area of the index element. The variant with the pins or pegs arranged on the index element is, however, the preferred one, since according to one aspect of the invention, a mechanical failure based on a torque between the abutment body and the index element would result in the pins or pegs breaking. According to one aspect of the invention, such a break or fracture of the respective pin or peg should affect the index element, which is easier to exchange and replace, rather than the more expensive abutment body. According to this aspect of the invention, the pins or pegs should therefore be part of the index element and not part of the abutment body in order to limit damage in the event of a fracture.

The index element intended for attachment to the distal end of the connecting pin of the abutment body and suitably designed with features of the variants described above is considered to be independently inventive.

With regard to the dental implant system, the above-mentioned object is achieved with a post part that can be inserted into the jawbone of a patient, and with a mounting part of the type described above, wherein the post part has a receiving channel provided for receiving the connecting pin including the index element arranged thereon in a rotationally secure manner.

According to one aspect of the invention, the attachment part is fixed to the post part by means of a connecting screw which engages with an external thread provided at the end into an internal thread in the receiving channel of the post part and whose screw head rests on a screw seat in the abutment body.

In such an implant system, there is naturally a desire to avoid unintentional destruction of components, particularly the index part, as far as possible. One possibility of destroying the index part during the abutment fitting or final assembly in the plaster model or in the patient's mouth would be if the index part is not positioned in the correct rotational insertion direction of the implant index and the connecting screw is mounted between the abutment and the implant. To avoid this risk, in an advantageous embodiment, the system components mentioned (first, ceramic abutment section, second abutment section intended as an index part, connecting screw and actual implant or post part) are coordinated with one another in terms of their dimensions in such a way that the connecting screw cannot engage in the associated internal thread in the post part or be screwed into it if the index of the index part is not inserted into the associated index of the implant.

In a further advantageous embodiment and according to a further aspect of the invention, the implant system is designed in such a way that the connecting screw cannot fall out of the abutment complex if it is not screwed into the implant. This makes it possible to pre-assemble the components in the sense that an ensemble of abutment body and index element (which together form the superstructure part or abutment) and the connecting screw can be prefabricated and, if necessary, stored for a longer period of time. If the abutment is then to be placed on the post part, this can be achieved particularly easily and, in particular, with particularly short treatment times for the patient by using such a pre-assembled ensemble and inserting it; all that is then required is to tighten the connecting screw in the post part.

Securing the connecting screw in this ensemble against accidental falling out can be achieved particularly easily according to one aspect of the invention and as described below. If the connecting screw is designed with a screw head, a screw shaft and a threaded area, the screw shaft being at least partially reduced in external diameter compared to the nominal thread diameter, the index element can preferably be designed such that the minimum central passage lies in its diameter between the nominal thread diameter and the reduced diameter area of the screw shaft. In this way, the connecting screw can be screwed through the index element, even without a thread being specifically provided in the index element, and is then caught in it so that it can no longer fall out.

• - E-Modul der Verbindungsschraube beträgt 50 % ±5 % / ±10 % des E-Moduls des Abutmentkörpers Und/oder
• - E-Modul des Indexkörpers < 100 %, bevorzugt <50 %, besonders bevorzugt <25 % des E-Moduls der Verbindungsschraube Und/oder
• - das Indexelement besteht zumindest teilweise aus einem Kunststoff

Surprisingly, another advantage and aspect of the invention has been shown. The principle that and how a connecting screw cannot fall out of the abutment is basically known; it is usually achieved by a hole cut into the abutment (e.g. in the case of abutments made of titanium). or -formed thread is achieved into which the connecting screw can be screwed. The function of preventing the connecting screw from falling out is usually given when the connecting screw is screwed in. However, it has been found that if the connecting screw is screwed in before packaging, it can still fall out during transport due to the associated vibrations without any additional security (e.g. a separate transport security). However, if according to a further aspect of the invention the E-modules of the three components abutment body, index element and connecting screw are suitably coordinated with one another, there will be no fracture transfer from a failing index element to the abutment body while preventing the connecting screw from falling out. For this purpose, the E-modules are preferably coordinated with one another as follows according to one aspect of the invention:

• - E-modulus of the connecting screw is 50 % ±5 % / ±10 % of the E-modulus of the abutment body and/or
• - E-modulus of the index body < 100 %, preferably <50 %, particularly preferably <25 % of the E-modulus of the connecting screw and/or
• - the index element consists at least partially of a plastic

If the index part consists at least partially of a plastic (e.g. PEEK, PPS or a fiber-reinforced, preferably carbon fiber-reinforced or otherwise reinforced plastic), the index element returns slightly after the screw has been turned and prevents the connecting screw from falling out.

According to a further aspect of the invention, which is considered to be independently inventive, the implant system is also designed so that if the index element needs to be replaced, the final rotational position of the abutment body relative to the post part is not affected as a result of the index part being replaced. In particular, the user who replaces the index part should not be able to fix the index element in an incorrect position during assembly. This problem is solved according to one aspect of the invention in that the number of possible rotational positions between the abutment body and the index element is advantageously exactly the same as between the abutment and the implant. If the number were different, error-free fixation of the index part to the abutment part could not be guaranteed in all cases. However, another option offers the advantage of preventing confusion. If the number of possible positions between the index part and the implant is a multiple of the number of possible positions between the abutment part and the index part, the dental technician or dentist cannot choose a position between the index part and the abutment part that changes the relative position between the abutment (abutment part) and the implant.

In addition to the advantage already described, which is achieved when the number of possible positions between the index part and the implant is either the same as or a multiple of the number of possible positions between the index part and the abutment part, there is also an advantage if the number of possible positions is deliberately different. This advantage does not exist if an abutment is individually manufactured using a CAD-Cam system during the prosthetic design of the abutment parts. In such a case, in the case of non-rotationally symmetrical abutments (e.g. angled or individually designed abutments), the dental technician can specify the rotational position of the index in relation to the rotational position of the area of the abutment that receives the prosthetics in the CAD in order to achieve an optimized design of the prosthetics. In such a case, the security against confusion has top priority. The situation is different with prefabricated non-rotationally symmetrical abutments. For example, with angled abutments or so-called aesthetic abutments. The latter often have an oval shape and a preparation border that is not at the same height. This ovality and preparation border is prepared for the expected anatomical conditions of the hard and soft tissue in the patient's mouth. There are pre-designs for front, canine and lateral teeth, and sometimes also individually for the upper and lower jaw. However, it is advantageous if the dentist takes the rotational alignment of the implant or the rotational index alignment of the implant into account so that the prefabricated abutments can actually be fixed by the dental technician in the desired and anatomically favorable rotational alignment. It should be noted that the dentist should have as few rotational options as possible for fixing the abutment when positioning the abutments. However, the dental technician would prefer a large number of options for rotational alignment. If, for example, an implant index allows 4 possible rotational positions, the practitioner must take this into account when positioning the implant in order to give the dental technician the chance of optimal positioning. If the Index between the index part and the abutment part does not allow 4 position options, but for example only 3, the dental technician would be able to allow two other positions for the index part in addition to the one specified original position, which would be plus or minus 30° to the original position. 5 positions would also be advantageous, as the gradation of the rotational options by the dental technician would now be even smaller. In such a case, an equal number or a multiple of each other would be rather disadvantageous. In this way, the rotational scope for the practitioner when inserting the implant in the bone could be increased, without having to accept the disadvantages of prefabricated and non-rotationally symmetrical abutments (non-rotationally symmetrical areas carrying the prosthetics).

The material properties of the materials particularly preferred for the abutment body or the index element can be summarized as follows: _ZrO2 : E-modulus: 210 GPa Bending strength: 600 - 1200 MPa Hardness: 1200 - 1400 Hv _{Al2O3 :} E-modulus: 320 - 400 GPa Bending strength: 300 - 600 MPa Hardness: 1500 - 1900 Hv Titanium: E-modulus: 105 GPa Elongation at break: < 10% (16%) Tensile strenght: 680 - 900MPa PEEK: E-modulus: Tension: 4.21 GPa - Bending: 0 GPa - Compression: 0 GPa Elongation at break: 11% Tensile strenght: 110MPa Bending strength: 170MPa Hardness: 99 MPa (ball indentation hardness) P.S.: E-modulus: Tensile: 4.1 GPa - Bending: 3,800GPa - Compression: 2.86 GPa Elongation at break: 6.5% Tensile strenght: 103MPa Bending strength: 166 MPa Hardness: 241 MPa (ball indentation hardness

• 1 ein Aufbauteil für ein Dental-Implantat in seitlicher Ansicht,
• 2 das Aufbauteil nach 1 in Explosionsdarstellung,
• 3 das Aufbauteil nach 1 in perspektivischer Darstellung in Explosionsdarstellung,
• 4 eine Klauenkupplung schematisch in unterschiedlichen Ansichten,
• 5 eine Stiftkupplung schematisch in unterschiedlichen Ansichten,
• 6 den Endbereich eines Abutmentkörpers des Aufbauteils gem. 1 in ausschnittsweise vergrößerter seitlicher Darstellung,
• 7 ein Indexelement des Aufbauteils gem. 1 in seitlicher und in perspektivischer Ansicht,
• 8 ein Dental-Implantatsystem im Längsschnitt,
• 9 das Dental-Implantatsystem nach 8 im perspektivischen Schnitt,
• 10 das Dental-Implantatsystem nach 1 in perspektivischer Darstellung in Explosionsdarstellung,
• 11 ein vormontiertes Abutment-Ensemble des Dental-Implantatsystems gem. 8 im Längsschnitt, und
• 12 den distalen Endbereich des Abutment-Ensembles gem. 11 in vergrößertem Längsschnitt in unterschiedlichen Zuständen.

An embodiment of the invention is explained in more detail with reference to a drawing. In it:

• 1 a component for a dental implant in side view,
• 2 the body part after 1 in exploded view,
• 3 the body part after 1 in perspective view in exploded view,
• 4 a claw coupling schematically in different views,
• 5 a pin coupling schematically in different views,
• 6 the end region of an abutment body of the abutment part acc. 1 in partially enlarged side view,
• 7 an index element of the superstructure part acc. 1 in side and perspective view,
• 8th a dental implant system in longitudinal section,
• 9 the dental implant system according to 8th in perspective section,
• 10 the dental implant system according to 1 in perspective view in exploded view,
• 11 a pre-assembled abutment ensemble of the dental implant system in accordance with 8th in longitudinal section, and
• 12 the distal end area of the abutment ensemble acc. 11 in enlarged longitudinal section in different conditions.

Identical parts are provided with the same reference numerals in all figures.

The body part 1 according to the 1 - 3 is for use in a 1 - 3 not shown in more detail. The abutment part 1 is used as a connecting or transition piece on the actual dental implant, also referred to as the “post part”, which is screwed into the patient’s jawbone. It comprises, on the one hand, a support surface 2 which acts as a superstructure and onto which the prosthetic or crown intended as a dental replacement can be attached, and, on the other hand, a connecting pin 4 which creates a connection with the inserted post part which can withstand the expected high force and moment loads, in particular the chewing forces. The connecting pin 4 can be inserted into a corresponding receiving channel of the post part and tapers continuously towards its distal end 6, at least in sections, so that a contact surface 8 is created for the connection with the post part.

The most common implant systems with abutments of this type are currently mostly made of titanium or a titanium alloy and are designed as two-part implants of the type described above. The abutments are usually provided with a rotational locking mechanism, known as an index, which is intended to ensure the correct rotational alignment of the abutment - and with it the prosthetics - relative to the post part - and with it the patient's oral cavity. However, there has recently been a sharp increase in demand for implants or their components that are not made of metal or at least do not allow metal to come into contact with human tissue, for example as a result of allergies or for aesthetic reasons.

In such systems, the aim is to manufacture, for example, the support surface 2 of a structural part 1 from an alternative material, in particular a ceramic material. However, such a choice of material brings with it other disadvantages, in particular due to the comparatively poor processability of ceramics, so that such implants have not been able to prevail.

To remedy this, the abutment part 1 is designed to provide a reliable index when connecting to the post part even when a ceramic base material is used. For this purpose, the abutment part 1 is designed in two parts and comprises an abutment body 10 as the first abutment part and an index element 12 as the second abutment part. These two components are designed to be functionally separate from one another, with the abutment body 10, in accordance with the aforementioned aim, consisting of a ceramic, in the exemplary embodiment a zirconium oxide ceramic, and being designed in the manner of a conventional abutment to establish the connection to the post part by means of the molded-on connecting pin 6 and to transmit the aforementioned comparatively large forces via the contact surface 8. However, the indexing, i.e. ensuring the correct rotational alignment of the abutment part 1 relative to the post part, is provided via the index element 12 which is also provided.

The indexing is carried out via the spatial shape of the index element 12. This comprises an inner ring 14 as a central element, on the outside of which a number of axially extending positioning ribs 16 are formed as indexing elements. When inserted into the receiving channel of the post part, these positioning ribs 16 are each inserted into corresponding grooves in the receiving channel provided as indexing elements, so that on the one hand a rotary locking mechanism is created, while on the other hand the insertion can only take place in a limited number of rotary positioning options.

The two-part design of the abutment part 1 makes it possible to provide a comparatively fracture-resistant and thus long-lasting concept despite the use of ceramic as the base material for the abutment body 10, since the areas that are particularly at risk of fracture due to the brittleness of the material and the limited space in the index area can be made of a different material. In particular, it is intended to manufacture the index element 12 from a material that is significantly more flexible and deformable than the abutment body 10, in particular by having an E-modulus of at most 60% of the E-modulus of the material forming the abutment body 10.

In the exemplary embodiment, the abutment body 10 is thus made of a ceramic material, in particular of a zirconium oxide ceramic, such as an aluminum oxide-reinforced zirconium oxide ceramic or a mixed ceramic or a ceramic mixture with a high proportion of zirconium oxide and/or aluminum oxide. It therefore has an E-modulus of approximately 210 GPa. In contrast, in the exemplary embodiment, the index element 12 is made of a plastic, in particular PPS, fiber-reinforced PPS, PEEK or fiber-reinforced PEEK, and thus has an E-modulus of less than 10 GPa, in the case of fiber-reinforced PEEK approximately 59 GPa.

With regard to the intended functional separation of the abutment body 10 (intended as a high-strength body for transmitting even high chewing forces) on the one hand and the index element 12 (intended for setting the correct rotational alignment when inserting the abutment part 1, without transmitting significant forces, but possibly flexible and deformable to a certain extent), the geometric relationships of these components relative to one another are also suitably selected. In particular, according to one aspect of the invention, the index element 12 is essentially limited in its extension in the longitudinal direction to the end region of the abutment part; according to one aspect of the invention, the length ratio between the index element 12 intended for indexing on the one hand and the connecting pin 4 intended for transmitting forces and moments, in particular a conical one, is suitably selected. In the exemplary embodiment, the index element 12 has a length of approximately 1.25 mm, whereas the connecting pin 4 has a length of approximately 3.5 mm. This satisfies the criterion provided according to one aspect of the invention that the index element 12 should have a length of at most 50%, preferably at most 33%, of the length of the connecting pin 4.

To create the connection between the abutment body 10 and the index element 12 attached to it, these are equipped with a coupling system 18. The coupling system 18 is designed as a mechanical connection system, although in principle, material-locking connections such as cementing or gluing would of course also be conceivable. In the event of a component breakage or the like, which, due to the choice of material, is more likely to affect the index element 12 than the abutment body 10, it can be important that the index element 12 can be replaced or exchanged quickly and easily. The mechanical design of the coupling system 18 therefore has the advantage that if the index element 12 needs to be replaced, no adhesive and/or cement residues remain on the abutment body 10 that would have to be removed at great expense.

In the exemplary embodiment, the coupling system 18 intended for connecting the abutment body 10 and the index element 12 is designed according to the model of a claw coupling 20 or pin coupling 22, as shown for example in 4 or 5 shown in different representations. A claw coupling 20 essentially comprises two coupling elements 24, each of which comprises a base disk 28 attached to an axle or shaft 26. A number of coupling pins 30 or claws are arranged on the base disk 28 in an axially aligned position with respect to the shaft 26, eccentrically, ie in the peripheral area of the respective base disk 28. This is shown in 4a The separated state of the claw coupling 18 shown in the figure is clearly visible.

For the force or torque connection of the coupling elements 24, the base discs 28 are engaged so that, as in 4b shown, the coupling pins 30 of both coupling elements 24 alternately engage with one another and this creates a positive connection between the coupling elements 24 as seen in the direction of rotation of the shafts 26. In this engaged state, the claw coupling 18 thus forms a rotary locking mechanism between the coupling elements 24; these are thus positioned to transmit a torque between the shafts 26.

A pin coupling 22, as shown in 5 is based on a similar operating principle. It includes, as shown in the separate representation of the components in 5a and in the separated state as shown in 5b can be clearly seen, a first, "male" coupling element 32 with a carrier ring 34, on which a number of coupling pins 30 are arranged in an axially aligned position with the shaft 26, eccentrically, i.e. offset from the central axis of the shaft 26. Matching and corresponding to this, the pin coupling 22 comprises a second, "female" coupling element 36 with a base ring 38, which has in its front surface 40 a number of shaped recesses 42, which are adapted in their positioning and dimensioning to the coupling pins 30 and are also arranged eccentrically to the central axis of the shaft 26. To produce the frictional connection, i.e. when engaging the clutch, then, as shown in 5c can be removed, the coupling pins 30 are inserted into the mold recesses 42 so that in the direction of rotation a positive connection and thus a rotary locking mechanism is created between the coupling elements 32, 36 and the transmission of torque becomes possible.

The coupling system 18 of the 1 - 3 The structure part 1 shown is designed based on these basic designs. In order to produce a rotary locking mechanism between the abutment body 10 and the index element 12, a number of coupling pins or pins 44, in the exemplary embodiment and according to one aspect of the invention four, are arranged on the index element 12 off-center with respect to the longitudinal axis of the system. In correspondence thereto, the abutment body 10 has at its distal end 6 a number of associated mold recesses 46, in the exemplary embodiment four, into which the pins 44 can engage when the components are assembled. In this assembled state, a positive connection of the pins 44 with the mold recesses 46 in the direction of rotation and thus a rotary locking mechanism is provided.

In detail, as is particularly evident from the partially enlarged lateral view of the distal end region of the abutment body 10 in 6 and the enlarged representation of index element 12 in 7 can be removed, the coupling system 18 is also designed so that, in addition to the aforementioned rotational position fixation, after the components have been connected, i.e. after the finger-like pins or pegs 44 have been inserted or pushed into the associated mold recesses 46, the two components can no longer be easily separated from one another, in particular without targeted action by the user. For this purpose, according to one aspect of the invention, the pegs 44 in combination with the associated mold recesses 46 are designed as latching or snap connections. In such a design as a snap lock or snap connection, the respective mold recess 46 initially has a widening from the apical direction towards the distal end 6, which tapers again towards the distal end 6 and thus forms an undercut or retention for the adapted shaped peg 44 on the index element. This shape of the mold recesses 46 is shown in the enlarged illustration in 6 clearly visible. Correspondingly, the cones, as shown in the enlarged illustration in 7 can be clearly seen, in a central region 48, as seen in the longitudinal direction, a thickening 50. With this thickening 50, the respective pin 44 can then snap into the associated mold recess 46. This snapping is also facilitated by the choice of material for the index element 12 in a manner considered to be inventive, because the use of a plastic or a material with a sufficiently low modulus of elasticity requires a certain deformability and elasticity of the pins 44, so that they can be introduced into the mold recesses 46.

Advantageously and according to one aspect of the invention, the shape of the mold recesses 46 is also selected to be particularly simple to manufacture with regard to possible manufacturing methods and with regard to large quantities. For manufacturing reasons, it is particularly advantageous to make the mold recesses 46 in the abutment body 10 in the green or white state. In this case, comparatively simple geometries that can be produced with rotating tools are particularly suitable, since other abrasive techniques, such as punching, are known to have a tendency to chipping or cracking even in the green or white state. For this reason, according to one aspect of the invention, and as shown in the enlarged illustration in 6 can be clearly seen, the respective mold recess 46 is basically designed as a round bore. Accordingly, the mold recess 46 has an essentially circular basic shape 52 in a side view. The insertion opening 54 required for the connection to the pin 44 and superimposed on the circular basic shape 52 can then be produced as a geometric entrance into this bore in advance or afterwards, e.g. with a cutting disk. In this case, according to an aspect regarded as independently inventive, this entrance or the insertion opening 54 is designed conically from the "open" side, i.e. from the distal end 6, so that the respective pin 44 of the index element 12 can be deformed comparatively slowly and thus in a way that is gentle on the material when inserted. As soon as the thickening 50 of the respective pin 44 is located in the round part of the respective mold recess 46, the material of the pin 44 can reset itself and thus prevent the index element 12 from falling out.

A dental implant system 60 with a mounting part 1 of the type described above, which is also considered to be independently inventive, is described in the 8 - 10 shown in different views. In addition to the abutment part 1, it comprises a post part 62, which is screwed into the patient's jawbone and onto which the abutment part 1 is placed in the manner of a connecting or transition piece. To accommodate the connecting pin 4 including the index element 12 arranged thereon in a rotationally secure manner, the post part 62 has a receiving channel 64, which comprises an inner index 68 adapted to the index element 12 in an indexing area 66. The index 68 comprises in the Embodiment, with regard to the intended design of the index element 12, in particular a number of, in the embodiment four, axial grooves 70 provided for receiving one of the positioning ribs 16 each. When the connecting pin 4 is inserted into the receiving channel 64, each of the positioning ribs 16 is thus inserted into one of the axial grooves 70, so that a rotary locking mechanism is created between the structural part 1 and the post part 62.

To fix the abutment part 1 to the post part 62, a connecting screw 72 is provided, which engages with an external thread 74 provided at the end into an internal thread 76 in the receiving channel 64 of the post part 62, and whose screw head 78 comes to rest on a screw seat 80 in the abutment body 10.

According to an aspect considered to be independently inventive, the dental implant system 60 is equipped with a specific safety concept with regard to the design and dimensioning of its components, which is intended to prevent unintentional damage to the components as a result of inadequate alignment. Damage to the components is to be prevented in the event that the index element 12 is not (yet) aligned in the correct rotational insertion direction relative to the post part 62 and the connecting screw 72 is tightened. In order to avoid this risk, in the exemplary embodiment the system components mentioned (abutment body 10, index element 12, connecting screw 72 and post part 62) are coordinated with one another in terms of their dimensions in such a way that the connecting screw 72 cannot engage in the associated internal thread 76 in the post part 62 or can be screwed into it if the positioning ribs 16 of the index element 12 are not at least partially inserted into the associated axial grooves 70 in the post part 62.

According to a further aspect of the invention, the components of the dental implant system 60 are designed in such a way that, in the manner of a pre-assembly, an abutment ensemble 90 suitable for final assembly on the post part can be prefabricated from the abutment body 10, index element 12 (which together form the abutment part 1) and the connecting screw 72 and can be stored for a longer period of time if necessary. Such a pre-assembled abutment ensemble 90 is in 11 shown in longitudinal section. In the case of use or treatment, i.e. when the abutment is to be placed on the post part 62 in the patient's mouth, this can be achieved particularly easily and in particular with particularly short treatment times for the patient. By using such a pre-assembled abutment ensemble 90, all that is then required is to tighten the connecting screw 72 in the post part 62.

For pre-assembly of such an abutment ensemble 90, the connecting screw 72 should be secured against accidental falling out of the screw channel 92 in the abutment body 10. According to one aspect of the invention, this is achieved in a particularly simple manner by a suitable selection of the geometry and parameters of the components. For this purpose, as can be seen from the enlarged sectional views in 12 removable, the index element 12 is provided with a retaining bead 94 on the inside, the inside width of which is slightly smaller than the outside diameter of the external thread 74 of the connecting screw 72. As shown in 12a can be removed, this means that the connecting screw 72 pushed into the screw channel 92 from above initially hits the retaining bead 94 with its external thread 74 and thus cannot be pushed further. The connecting screw 72 is then screwed in, whereby the external thread 74 comes into engagement with the retaining bead 94 due to the choice of material and deformability of the index element 12. The connecting screw 72 can thus be "screwed through" the retaining bead 94 so that the external thread 74 is then located beyond the retaining bead 94. This state is in 12b shown. Then, due to geometry, as shown in 12c shown, the connecting screw 72 can no longer be pulled back over the retaining bead 94 without screwing. In the "forward direction", however, the screw head 78 prevents further movement of the connecting screw; this is thus fixed in the screw channel 92 and secured against accidental falling out. In particular, the minimum central passage of the screw channel 92 given by the clear width of the retaining bead 94 lies in its diameter between the nominal thread diameter of the external thread 74 and an axially adjacent, reduced-diameter area 96 of the screw shaft 98. In this way, the connecting screw 72 can be screwed through the index element 12 even without a thread being specifically provided in the index element 12 and is then caught in it so that it can no longer fall out.

List of reference symbols

1

Body part

2

Carrier surface

4

Connecting pin

6

distal end

8th

Contact surface

10

Abutment body

12

Index element

14

Inner ring

16

Positioning ribs

18

Coupling system

20

Claw coupling

22

Pin coupling

24

Coupling element

26

Wave

28

Base disc

30

Coupling pin

32

Coupling element

34

Carrier ring

36

Coupling element

38

Base ring

40

Frontal area

42

Mould recess

44

cone

46

Mould recesses

48

Area

50

thickening

52

Basic form

54

Slot opening

60

Dental implant system

62

Post part

64

Recording channel

66

Indexing area

68

index

70

Axial groove

72

Connecting screw

74

External thread

76

inner thread

78

Screw head

80

Screw seat

90

Abutment ensemble

92

Screw channel

94

Retaining bead

96

Area

98

Screw shaft

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• WO 2012065718 A1 [0010]

Claims (9)

Abutment part (1) for use in a dental implant system (60), with an abutment body (10) which has a connecting pin (4) which can be inserted into a corresponding receiving channel (64) of a post part (62) and which tapers continuously at least in sections in the direction of its distal end (6), and with an index element (12) arranged on the distal end of the connecting pin (4) in a rotationally secure manner and made of a material which has an E-modulus of at most 60% of the E-modulus of the material forming the abutment body (10). Body part (1) after Claim 1 , the abutment body (10) of which is made of a ceramic material, preferably of a zirconium oxide ceramic, an aluminium oxide-reinforced zirconium oxide ceramic or a mixed ceramic or a ceramic mixture with a high proportion of zirconium oxide and/or aluminium oxide. Body part (1) after Claim 1 or 2 , the abutment body (10) of which is made of a material with an E-modulus of at least 180 GPa, preferably of at least 200 GPa. Body part (1) according to one of the Claims 1 until 3 whose index element (12) is made of a plastic, preferably PPS, fiber-reinforced PPS, PEEK or fiber-reinforced PEEK. Body part (1) according to one of the Claims 1 until 4 whose index element (12) is made of a material with an elastic modulus of at most 120 GPa, preferably at most 80 GPa, particularly preferably at most 10 GPa. Body part (1) according to one of the Claims 1 until 5 , in which the abutment body (10) and the index element (12) are provided in their connection region with a coupling system (18) designed as an indexing system, in which, in order to form a rotational locking mechanism between the abutment body (10) and the index element (12), a number of eccentrically arranged, axially aligned pins (44) are arranged on one of these components (10, 12) with respect to the longitudinal axis of the system, which pins each engage in the axial direction in associated mold recesses (46) in the respective other component (10, 12). Index element (12) for use with an abutment body (10) as a structural part (1), in particular according to one of the Claims 1 until 6 , in a dental implant system (60), with a coupling system (18) provided for distal end attachment to a connecting pin (4) of the abutment body (10) which can be inserted into a corresponding receiving channel (64) of a post part (62) and which tapers continuously at least in sections towards its distal end (6), wherein the index element (12) is made of a material which has an E-modulus of at most 60% of the E-modulus of the material forming the abutment body. Dental implant system (60) with a post part (62) which can be inserted into the jawbone of a patient, and with a superstructure part (1) according to one of the Claims 1 until 6 , wherein the post part (62) has a receiving channel (64) provided for receiving the connecting pin (4) including the index element (12) arranged thereon in a rotationally secure manner. Dental implant system (60) according to Claim 7 , in which the abutment body (10) as the first structural part, the index element (12) as the second structural part, a connecting screw (72) provided for fastening the structural part (10) in the post part (62) and the post part (62) itself are coordinated with one another with regard to their dimensions and measurements such that the connecting screw (72) cannot engage in the associated internal thread (76) in the post part (62) or can be screwed into it if the indexing elements (16) of the index element (12) are not at least partially inserted into the associated indexing elements (70) in the post part (62).

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