Patent Application
20210137649
The invention relates to an abutment for an endosseous dental implant and a dental implant insertable into the jawbone with a base body and the abutment according to the invention.
Nowadays, such dental implants, which are usually made of titanium or titanium alloys, usually have shapes approximating the natural tooth root, such as helical, cylindrical or stepped cylinders.
In most implant systems, implant abutments are placed on the actual implants, the so-called base bodies, which are connected to the implant by a screw that can be screwed into the implant body along the longitudinal axis of the implant. These establish the connection between the implant and the prosthetic construction on the implant. A distinction is made between removable and fixed constructions.
Wth such implants, there is often the problem that the desired longitudinal axis of the abutment does not coincide with the longitudinal axis of the implant. This problem occurs particularly when the most parallel abutments possible are desired on several implants with non-parallel axis directions.
In some applications, however, there is also a need to be able to position the abutment/fixing head at an angle to the base body, as the base body must occasionally be implanted at an angle into the jawbone, e.g. due to local bone atrophy, while the fixing head should have a different angular orientation for optimum attachment of the denture and introduction of the chewing forces absorbed by it.
For this purpose, it is already known to provide a ball head at the coronal end of a base body, on which a counterpart should be secured against rotation by means of a locking screw acting on the surface of the ball head. However, there is no guarantee that the counterpart can be firmly and securely connected to the base body.
Thus, a number of proposals for solutions to these problems are known in the state of the art.
An adjustable support for a prosthetic tooth in accordance with U.S. Pat. No. 4,832,601 comprises an abutment element with an opening for receiving a bolt element which engages with a nut element.
A stop element is sandwiched between a head portion of the bolt element and an enlarged collar portion of the nut element. The stop element can be swivelled to a desired position and the bolt and nut elements are tightened to lock the stop element in the desired position. A prosthetic tooth, which has an opening of complementary shape with respect to the stop element, engages the stop element to assume the angular orientation of the stop element.
Furthermore, U.S. Pat. No. 5,194,000 reveals an implant for use in oral and dental surgery, in particular in mandibular surgery, comprising a component in the form of a truncated cone substantially coaxial with the implant, at the coronal end of which a spherical element is provided, the spherical element being capable of being received in a corresponding cavity provided in the prosthesis in order to hold the prosthesis in relation to the implant.
A different solution is proposed in U.S. Pat. No. 5,195,891. This concerns an implant system and in particular an anchoring device for adjustably holding one or more prosthetic teeth or devices in a desired orientation relative to the insertion path of a restorative device, especially in the case of patient-removable restorative devices.
U.S. Pat. No. 5,302,125 describes a dental prosthesis implant that has angular rotation capability and improved locking between the implant holder and the abutment prosthesis.
A further solution for aligning the abutment mounted on the implant base bodies, whose longitudinal axes include an angle of up to 45° to each other, is proposed in DE-OS-19959366, for example. In this publication, an implant abutment is proposed which can be screwed to the implant by means of a screw, whereby the implant abutment consists of an abutment and a connecting part which can be placed on the implant at the basal of the abutment, whereby the abutment can be connected to the connecting part by a joining process, preferably by welding or gluing, with its longitudinal axis angled at any desired angle up to a limit angle relative to the longitudinal axis of the screw. However, this type of embodiment has the disadvantage that, after joining by welding or gluing, the components are fixed in the structure to each other and their position to each other can no longer be corrected.
A further development of the abutment for dental implants is described in EP1547543. The abutment described there for anchoring a dental prosthesis to a dental implant is provided with a post arrangement and a screw-in construction connected to it for screwing into the dental implant and has a ball joint between the post arrangement and the screw-in construction. The screw-in structure and the post assembly are provided with means for rigidly fixing the ball joint to the implant and the post assembly to the ball joint and the ball joint to itself. Disadvantages of this construction are the mechanical strength and the construction consisting of a multitude of individual parts.
According to WO2008/019774, a dental implant comprises two implant parts, a primary crown and a secondary crown, the secondary crown being the support for a prosthesis or bridge which can be placed on the outer shell of the secondary crown. The outer shell of the secondary crown is at least approximately circular or semi-circular in at least one plane and can be swivel-mounted accommodated in a bearing of the prosthesis or veneer.
An assembled angle connection for connecting an abutment to a dental implant at a predefined angle is described in WO2010/150188. The assembled angle connection comprises a basal element that can be connected to the dental implant and an apical element that can be connected to the abutment. The apical element is connected to the basal element, which forms a predefined angle. The assembly of the compound angle joint of the two elements allows to achieve a strong and stable connection between the base element and the dental implant, between the apical element and the abutment and between the base element and the apical element. The connection angle joint can be used in prostheses in order to make the best use of the bone structure of the jaw.
The EP2647347 concerns a prosthetic fixation with a support piece fixable in a dental implant and a fastening assembly that can be coupled to a prosthetic structure. The fastening assembly comprises a primary element with a substantially spherical cavity and is provided with a threaded through-bore into which a screw with a spherical head is inserted. Thus, the spherical head can be inserted into the inner area of the connecting section of the support and the wall forming the substantially spherical cavity of the primary element can be adjusted to partially and externally surround the connecting section of the support, so that the mounting assembly is rotationally coupled.
According to EP2684538, a screw channel-straightening device for a dental superstructure has a screw channel part and a part interacting with the implant. The proximal end of the screw channel part is cup-shaped so that the inner bottom surface has a concave shape and the outer bottom surface has a convex shape. The screw bore of the screw element seat is an oblong bore, and the part cooperating with the implant comprises a lower implant cooperation part for connection to a dental implant and an upper implant cooperation part. The lower implant-cooperating part has a distal concave seat and the upper implant-cooperating part has a proximal convex bottom surface with a radius corresponding to the radius of the concave seat of the lower implant-cooperating part to form a first ball joint. The upper implant cooperating part has a distal concave seat with a radius corresponding to the radius of the outer bottom surface of the screw channel part to form a second ball joint.
EP2835110 describes a prosthesis-mounting bracket which is freely adjustable in angle and position and has a ball joint and ball joint angle limiting cover.
U.S. Pat. No. 9,320,577 describes a dental implant abutment connection assembly comprising a seating portion adapted for fixation to a dental implant and a ball portion having a spherical head with a threaded post extending therefrom for mounting the ball joint in a user-selectable threaded bore in the socket to properly align an integral locating attachment cap attached to the ball head for fixing a dental prosthesis to the joint assembly.
A further fixing system for a dental implant having a spherical portion, the fixing system comprising a body with a seat forming a cavity, is described in WO2015/152815. The fixing system is characterised in that the body comprises at least two parts, which together form the seat. The parts are arranged so that the seat can embrace the spherical portion of the dental implant and so that the seat is movable between a first position in which the parts can move relative to each other and a second position in which the parts are prevented from moving relative to each other.
WO2016/170376 also describes a structure that allows continuous angle adjustment for fixing a single dental device in an implant.
Disadvantages of the systems known in the state of the art are the mechanical stability and position adjustments that decrease in strength as well as the constructions consisting of a multitude of individual parts.
The invention is therefore based on the task of further developing the generic structure of an implant abutment for a dental implant in such a way that a secured alignment of the structure and fixing of the components of the structure and further dental components with respect to each other can be achieved by simple means.
According to the invention, this task is solved by providing an abutment for a dental component such as a dental prosthesis, with
Half-ball head in the sense of the above definition means, according to the invention, that the ball head arranged at the apical end below the section of the fixing head for the later fixation of the dental component such as dental prosthesis, conical cap, etc., in relation to the arrangement in the jaw, is at least half-ball surrounded by the ball head receptacle. When the ball head is inserted into the ball head receptacle, the ball head is pressed against the swivel opening in the ball head receptacle and slides into the ball head receptacle due to the elasticity of the material. In this position, the ball head can be secured against falling out without jamming due to its slightly larger diameter compared to the swivel opening. The insertion of the ball head into the receptacle can also be made easier by thermally shrinking the ball head by means of so-called cold shrinking with dry ice or liquid nitrogen. The ball head is then inserted into the ball head receptacle in the cooled state, brought to room temperature and then at least half of the ball head is embraced in the ball head receptacle. In a next step, the abutment consisting of the abutment base and the fixing head can be inserted into the implant and screwed into the implant with a fixing screw inserted through the through-bore in the fixing head.
The fixing head can be braced in the ball head receptacle by introducing bracing means through the through-bore, which causes the fixing head's ball head to jam in the ball head receptacle. Examples of clamping means are split pins, mandrels or preferably a clamping screw, whereby the latter can be screwed into an internal thread located in the through-bore in the fixing head and either causes jamming directly through contact with the ball head receptacle or indirectly jams the ball head against the ball head receptacle by pressing the apical end of the ball head apart.
In a further advanced embodiment, the ball head has at least one slot, in particular two slots cutting through the ball head to the through-bore to form ball head segments, wherein each slot being arranged at an angle of preferably 0° to 45°, preferably axially (0°), to the longitudinal axis of the through-bore.
In particular, the ball head may have at least three, four, five, six, eight or ten, preferably a multiple of two, slots penetrating/cutting through the ball head on both sides of the through-bore to form, for example, wedge-shaped ball head segments, each slot being arranged at an angle of 0° to the longitudinal axis of the through-bore, so that the axis of the through-bore is always in one plane with the planes formed/spanned by the slots, which have an angle of 360° divided by the number of slots to each other. According to the invention, a slot extends from the outside of the ball head to the through-bore. If there is an even number of slots, the slots are preferably arranged opposite to each other in one plane and divide the ball head into a number of ball head segments corresponding to the number of slots. If there are four, six, eight or more slots, the segments have the shape of wedge-shaped ball head segments in the number of four, six, eight or more.
The axial length of at least one of the slots cutting through the ball head to the through bore should be at least half the axial diameter of the ball head. Preferably, the slots in the ball head can be formed up to the transition area to the hollow cylindrical fixing head, up to the thread for the clamping screw. Thus, the axial length of the slot(s) can be approximately the same as the diameter of the ball head.
The at least one slot cutting through the ball head to the through-bore is preferably open towards the apical end of the ball head to facilitate jamming of the ball head over the ball head segments in the ball head receptacle. The ball head is preferably divided by slots into four, six or eight ball head segments in the manner of ball segment wedges. The ball head preferably has a spherical cavity, and the ball head segments then each have a cup-shaped form.
In particular, the through-bore penetrating the fixing head has a guide section and a clamping section and an internal thread arranged at the end of the clamping section facing the guide section, into which a clamping screw can be screwed. The clamping screw is dimensioned in length and diameter so that the clamping screw, in the screwed-in position, securely clamps the ball head segments with the ball head receptacle.
The through-bore penetrating the ball head and preferably widened in the ball head to form a hollow ball can have an inner collar or tapered edge in the clamping section in the area of the slots, preferably below the largest diameter range, usually in the middle of the axial length of the slots or below it, against which the clamping screw rests when screwed in, thus pressing the ball head segments apart and clamping them securely in position in the ball head receptacle in the screw-in position.
In order to facilitate insertion of the ball head into the ball head receptacle, particularly in the case of brittle materials, the abutment base may have a thread, preferably with one thread only, at the swivel opening facing the fixing head, which can be engaged with a corresponding thread, preferably with one thread only, on the ball head of the fixing head, preferably in the area of the largest diameter of the ball head, when the fixing head is inserted in the ball head receptacle.
Thus, the ball head can be screwed with the thread into the thread at the swivel opening of the ball head receptacle, and after one or more rotations, the ball head is embraced by the ball head receptacle and can be swivelled in the ball head receptacle within the range limited by the swivel opening.
In another embodiment, the abutment base may have at least one groove or projection on the swivel opening facing the fixing head, which can be engaged with a corresponding projection or groove on the ball head of the fixing head, preferably in the area of the largest diameter of the ball head, when the fixing head is inserted into the ball head receptacle, in each case in the manner of a tongue-groove connection. In this way, the ball head with the groove or tongue can be inserted in the corresponding tongue or groove at the swivel opening of the ball head receptacle, and after a short insertion the ball head is embraced by the ball head receptacle and can be swivelled in the ball head receptacle within the range limited by the swivel opening.
To improve mobility, the front edge of the abutment base can also be provided with a chamfer for the swivel opening, which allows the swivel angle to be increased.
The invention also relates to a dental implant with a base body and with an abutment as described above, and in particular a dental implant with a substantially cylindrical base body with an annular recess and with a bore coaxial with the annular recess, which can be inserted into a bore introduced into a jawbone and which has a thread apically for fixing a fixing screw, and the abutment which can be inserted into the annular recess of the base body and which consists of an abutment base and fixing head as described above. The abutment may have a bore penetrating the abutment base coaxially with the annular recess to receive a retaining screw with an apical external thread and a coronal screw head, or it may be provided with an external thread at the apical end of the abutment base.
The abutment can be fixed in the base body by means of the retaining screw, which can be inserted into the bore of the abutment base, or by the apical external thread on the abutment base. For this purpose, the retaining screw can be screwed into the thread located at the apical end of the base body by means of an Allen key engaging in the Allen key located in the screw head, which can be inserted through the axial bore of the retaining head into the bore of the abutment base and engaged with the Allen key screw head.
If the abutment is designed with a thread at the apical end, the abutment can be screwed into the base body, for example, by means of a tool such as a spanner, using spanner flats provided on the outside of the ball head receptacle.
The corresponding sections on the base body and abutment can be designed as tube-in-tube sections, which allow the abutment to be guided and supported in the base body without form-fitting elements, also known as indexing elements. In this type of design, the abutment consisting of the abutment base and fixing head is inserted into the base body via the abutment base. The abutment base is secured in the base body by means of the retaining screw or by means of the thread at the apical end, and the fixing head is swivelled into the desired position and secured in the abutment base by means of the clamping screw. On the fixing head, the dental component can be arranged like a dental prosthesis, a dental cone or a carrier for the dental prosthesis via an internal or external thread on the fixing head. The dental prosthesis or carrier can also be fixed to the fastening head via a thread in the screw head of the clamping screw or by means of dental cement.
In the embodiment of the abutment base with retaining screw or the embodiment of the abutment base with thread at the apical end, the corresponding sections on the base body and abutment can either be designed as tube-in-tube bearing(s) with corresponding diameters or as corresponding form-fitting sections with possibly further corresponding stepped cylindrical sections.
Thus, according to the invention, in a further embodiment the base body and the abutment can have form-fitting sections complementary to one another, the form-fitting section of the base body and the form-fitting section on the abutment base of the abutment preferably having two to six form-fitting element pairs complementary to one another in shape in the form of radially inwardly directed tongues on the base body which are axial to the longitudinal axis of the base body and corresponding grooves on the abutment in the manner of a tongue-groove connection.
According to the invention, the base body is provided with screw-in elements selected from inner polygons (preferably double, triple, square, pentagonal, hexagonal), cams, indentations and Morse taper Morse cone, preferably two to six, which are engaged for screwing the base body into the jaw by means of a screw-in tool with respectively complementary screw-in elements such as outer polygon (preferably double, triple, square, pentagonal, hexagonal), indentations, cams and Morse taper Morse taper on the screw-in tool.
In these embodiments, no screw-in elements are arranged on the abutment base that are complementary to the screw-in elements on the base body, and preferably the form-fitting elements, also known as indexing elements, are arranged on the abutment base in such a way that they have no contact with the screw-in elements on the base body and are designed separately from the screw-in elements. This embodiment is designed so that the application of force when the base body is screwed into the jaw with the aid of the screw-in tool takes place exclusively via the screw-in elements and additionally, if desired, via the contact of the screw-in element with the lateral surface and/or root of the tongue assigned in the screw-in or screw-out direction.
Preferably, a form-fitting element of a tongue-groove connection is arranged between two adjacent screw-in elements on the base body. Thus, with two to six complementary form-fitting elements in the form of radially inwardly directed tongues, which are axial to the longitudinal axis of the base body, a screw-in element can be arranged on the base body between two adjacent form-fitting elements.
If, in another embodiment, the base body is to be screwed into the jaw by means of the application of force via the abutment with the aid of a screw-in tool engaging key surfaces on the abutment/fixing head, the form-fitting section of the base body and the form-fitting section of the abutment base of the dental implant according to the invention can be screwed into the jaw by means of complementary screw-in elements which are brought into engagement with each other when the abutment base is inserted into the base body, wherein the base body and the abutment base are fixed non-rotatably relative to one another in the engagement position of the mutually complementary screw-in elements, and wherein the mutually complementary screw-in elements on the base body and abutment base are preferably designed as respective pairs of screw-in elements of complementary shape, selected from pairs of inner edge-outer edge (preferably), cam-indentations and Morse taper-Morse taper.
In particular, in the dental implant of the invention, the annular recess of the base body may comprise an apical guiding section, a form-fitting section arranged coronally to the apical guiding section and a coronal end section arranged coronally to the form-fitting section, and the abutment base may then correspondingly comprise an apical guiding section, a form-fitting section and a coronal end section corresponding to the respective sections of the base body.
In the embodiments according to the invention, when a retaining screw is used, the screw head of the retaining screw in the use position is preferably recessed in the abutment base in such a way that a swivel movement of the fixing head in the swivel opening of the abutment base is not impaired.
When using the abutment according to the invention with abutment base with ball head receptacle and with fixing head with apical ball head, it is not absolutely necessary to use indexing between the base body and abutment to align the fixing head, since the desired, mostly vertical alignment of the fixing head in the oral cavity of the patient can be achieved in any direction within the swivel opening after the abutment base has been fixed in place.
Other forms of implant and abutment are included in further embodiments of the invention, which are shown in particular in
The components of the abutment or base body according to the invention can be produced by mechanical processing from blanks using CNC-processes or laser-processes. These include structure-removing processes as well as structure-building processes, which make use of the application of high-energy radiation to the blank or powder.
As a structure-removing process, laser ablation can be used very selectively to remove individual layers from the blank/substrate without significantly damaging the underlying layers or the substrate. The ablated structures can be spot-shaped, linear or flat.
According to the invention, structural or layer-building processes for the manufacture of three-dimensional objects such as implants are to be mentioned: Rapid Prototyping, Rapid Tooling, Rapid Manufacturing, Laser Sintering, and EBM.
Furthermore, laser microsintering or an ablative process can be used as a method for creating microstructures on the implant surface. The processing of ceramic powders in high quality is also possible.
The basic prerequisite for these processes is usually that the geometric data of the product are available in three dimensions and can be processed as layer data. From the available CAD data of the component, the data is converted into a data format, for example an STL format, in order to be able to structure the surface of a blank specifically by means of the aforementioned processes or to build up the blank in a structured way from powder.
The known devices, also for rapid prototyping processes, each have such a data interface, which serves to provide geometric information from three-dimensional data models.
By the inventors here, a process was proposed in which surfaces provided with regular/periodically repeating microstructures can be produced by exposing the surface of the blank to high-energy radiation in one or more patterns, which can be represented from a periodic function converted into an STL data set, whereby a structure-removing process is used. Alternatively, a blank provided with regular/periodically repeating microstructures can be produced using a structure-building process. In such a structure-building process, a quantity of powder present on a blank as a carrier can be exposed in one or usually several steps to the high-energy radiation in one or several patterns which can be represented from a periodic function converted into an STL data set, and the structure with the pattern is generated on the blank.
A less complex alternative is a structure-removing process in which the desired structure is created by removing surface material.
The blank obtained, which has been provided with a regularly microstructured surface by build-up or ablation processes, may also be subjected to a treatment to produce a second regular microstructure using a periodic function derived from a periodic function converted into an STL data set and/or a wet chemical treatment to produce a nanostructure.
The material of the abutment or implant can be selected from the group of metals, metallic alloys, ceramic materials (e.g. zirconium oxide), glasses and polymers (e.g. PEEK, polyetheretherketones) as well as combinations thereof.
The abutment and/or implant is preferably made of a material selected from the group of metals, metallic alloys and combinations thereof with ceramic materials. Preferably, the implant material used consists of metallic materials such as pure titanium or metallic titanium alloys, chrome/nickel/aluminium/vanadium/cobalt alloys (e.g. TiAlV4, TiAlFe2.5), stainless steels (e.g. V2A, V4A, chrome-nickel 316L) or a combination thereof with ceramic materials such as hydroxyapatite, zirconium oxide, aluminium oxide, where the metallic material is present as a composite material with ceramic material. The non-metallic materials, including polymers such as PEEK, can also be used alone without combination with other materials.
It may be of particular advantage if the abutment base is made of a material selected from the group of metals, metallic alloys and combinations thereof with ceramic materials, and the fixing head is at least partially made of a polymer material such as PEEK. In this design, a flexibility of the material, especially the polymer material of the fixing head is advantageous both when inserting the fixing head into the abutment base and when clamping/tightening the fixing head in the ball head receptacle of the abutment base. On the one hand, it is easier to insert the ball head into the ball head receptacle of the abutment base, and on the other hand, it is easier to clamp it in position using a clamping screw. After the implant has been inserted into the jaw and the abutment then inserted into the implant is usually aligned vertically, the dental component that is to be placed on the fixing head can be connected to the abutment base, e.g. using dental cement, thus creating a load-bearing and firm connection via the abutment to the base body.
Below are examples of the design of the abutment and its components as well as the single tooth implant according to the invention, explained in detail using the schematic drawings. Thereby, it is shown in:
As shown in
According to
For mechanical and geometrical reasons, the use of three screw-in elements such as inner edge surfaces on the base body 10 is advantageous, but two to six screw-in elements such as inner edge surfaces can also be provided. On the inner edge surfaces, corresponding outer edge surfaces of a screw-in tool not shown or outer edge surfaces 72 of the abutment base 50 can engage as screw-in elements, as long as the form-fitting elements on base body 10 and abutment base 50 can be reliably engaged when inserting the abutment base 50. Between the inner edge surfaces, projections such as tongues 26 can be provided in an appropriate number in the design forms according to the invention, whereby the tongues and the inner edge surfaces can extend axially over the entire axial length of the form-fitting section for reasons of improved power transmission or indexing and enable torque transmission via the outer edge surfaces of the screw-in tool or also of the abutment base which are complementary in shape.
When the retaining screw 120 is screwed into the thread 14 provided at the apical end of the base body, the screw head 126 comes into contact with the cone collar 58. The screw head is dimensioned in such a way that it allows free swivelling of the ball head 82 located in the ball head receptacle 60.
The dental component not shown can be placed on the front face 64 in the form of a crown or a holder for a prosthesis. In order to ensure that the abutment base 50 fits securely in the base body 10, a guide section 66, a form-fitting section 68 and an end section 70 are provided on the outside of the abutment base 50 as shown in
The abutment base 50 can be inserted into the base body after the base body has been screwed into the jaw and is secured against rotation by the form-fitting grooves and, if present, by the polygonal surface pairs in the base body and abutment.
The fixing head 80 shown in
As shown in
Although it is possible that the slots 92, which are arranged axially to the longitudinal axis of the through-bore 84, are not slotted as far as the apical end of the ball head or the fixing head and apically connecting bars are present between the segments 96, it is preferred that the slots extend as far as the apical end of the clamping section 86 and allow resilient radial movement of the ball head segments 96. This also facilitates removal of the fixing head after unscrewing the clamping screw 100. The ball head 82 can preferably have a reduced wall thickness around the axial through-bore 84 above the inner collar 88 and, if necessary, also below the inner collar 88—in the manner of a “hollow”—which allows the ball head segments 96 to expand when the screw tip 106 is in contact with the inner collar 88 when screwed in and allows the ball head segments 96 to spring back when the tensioning screw 100 is removed.
Although in the simplest embodiment, even one diametral slot, i.e. two slots (partial slots) extending to the axial longitudinal axis of the through-bore are sufficient for clamping, it is preferable to have at least three, preferably four or more slots, especially a multiple of two slots, which can preferably each be continuously aligned up to the longitudinal axis of the fixing head. Thus, in a plan view from the apical end towards the ball head, the wedge-shaped ball head segments 96, separated from each other by the slots, are formed, which are connected at their coronal end by a ball head base, which connects the individual approximately wedge-shaped ball head segments 96. In the area of the ball head segments, for example, a circumferential inner collar can also be provided in the area of the largest possible diameter of the ball head in the through-bore, against which the screw tip 106 of the tensioning screw 100 rests under contact pressure when the screw is screwed into the internal thread 90 of the fixing head and presses the ball head segments apart in the screw-in position.
The retaining screw shown in
The embodiments of abutment base 50 shown in
Thus,
The embodiment of the inventive abutment base 50 shown in
In the embodiment shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2018 110 946.6 | May 2018 | DE | national |
| 10 2019 203 222.2 | Mar 2019 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/DE2019/100402 | 5/5/2019 | WO | 00 |
