WO2004056286A1

WO2004056286A1 - Prosthesis support, prosthesis-anchoring device and method for manufacturing a prosthesis support

Info

Publication number: WO2004056286A1
Application number: PCT/SE2003/000952
Authority: WO
Inventors: Per-Ingvar BRÅNEMARK
Original assignee: Medevelop Ab
Priority date: 2002-12-19
Filing date: 2003-06-10
Publication date: 2004-07-08
Also published as: AU2003241257A1; SE0203788L; SE0203788D0; SE526696C2

Abstract

The invention relates to a prosthesis support (27) comprising a frame (21) having a planar surface (22). The prosthesis support has a plurality of through holes (19, 31). According to the invention, the prosthesis support comprises at least one tubular element (16) which forms one of the holes and which extends through an opening (20) recessed in the frame (21). Each opening (20) is wider than the outer contour of the tubular element (16) so that a space is formed between the opening (20) and the tubular element (16). The space is filled by a glue (28), which is adhered to the tubular element (16) and the limiting surface of the opening (20). The tubular element (16) has a planar end surface located in the same plane as the planar surface (22) of the frame (21). The invention also relates to a prosthesis-anchoring device intended to be used in connection with the invented prosthesis support. Furthermore, the invention relates to a method for the manufacture of the invented prosthesis support and a method for fastening a prosthesis in a number of fixtures.

Description

PROSTHESIS SUPPORT, PROSTHESIS-ANCHORING DEVICE AND METHOD FOR MANUFACTURING A PROSTHESIS SUPPORT

Field of the Invention The present invention relates to components and methods related to a new procedure for attaching prostheses, such as, e.g., tooth prostheses.

In a first aspect, the invention relates to a prosthesis support especially adapted for the new procedure and which is intended to carry a prosthesis-holding body. The prosthesis support is of a type that comprises a frame having a first and a second side, which first side has a planar surface and which prosthesis support is provided with a plurality of through holes running between the first and second sides of the frame. A prosthesis support of this type may, for instance, bemused in anchoring tooth prostheses. In such cases, the prosthesis support has the shape of a bar, usually denominated lower bar. The function of a lower bar is to provide a support element anchored in the jawbone for one or more prosthesis teeth, the lower bar being fastened in the bone tissue of a patient by a number of fixtures, i.e., anchor screws. The lower bar interacts with a prosthesis-holding body, which, in the case of tooth prostheses, consists of a second bar where the prostheses are fastened, which latter bar usually is called upper bar. The upper bar with the prostheses is fastened to the lower bar.

In a second aspect, the invention relates to a particular prosthesis- anchoring device for use in the fastening of a prosthesis support in the bone tissue of a patient and which prosthesis-anchoring device is especially adapted for the novel procedure. The prosthesis-anchoring device is of a type that comprises a fixture and a fastening element, which fixture has an application part and an anchoring part provided with a screw thread, which anchoring part is arranged for screw-in into the bone tissue of a patient.

In a third aspect, the invention relates to a method for the manufacture of a prosthesis support according to the invention.

In a fourth aspect, the invention relates to a method for fastening a prosthesis to a number of anchored fixtures, to which a prosthesis support is fastened to said fixtures and a prosthesis-holding body is fastened to the prosthesis support. Background of the Invention

It is previously known to anchor one or more prostheses in the bone tissue of a patient while using a prosthesis bar, which is fastened in the bone tissue by means of a number of fixtures. One such method and components therefor is described in WO 97/49351. The system described in this specification comprises a prosthesis bar, i.e., a lower bar having a number of through holes for the fastening of the lower bar to a number of fixtures. The holes of the bar are arranged to receive fixing screws that are threaded through the holes and tightened in the outer ends of the respective fixture. The holes are distinct, and dimensioned for the screws being able to exactly be threaded through the same. Therefore, the fastening of the lower bar implies that the fixtures to which it is to be tightened are exactly positioned in correspondence to the location of the holes. Furthermore, it is necessary that the fixtures have exact directions, in the normal case parallel direc- tions, and that the fixtures are screwed into the jawbone to exactly adapted height. In order to facilitate this, said specification describes a number of facilities, such as drill templates and the like. The described system is certainly well adapted to its purpose and has turned out to result in prosthesis anchorings that are well functioning and have a long durability. However, the system has the disadvantage that great skill and precision is required for drilling the holes in the jawbone and screwing the fixtures into the same. This means that great experience and a very high skill is required of the operator that is to effect the prosthesis anchoring. This implies that the prospect of the operation method becoming spread in such a large extent that the needs give cause for, becomes limited by virtue of inadequate access to skilled operating personnel. Another disadvantage is that the distinct holes of the lower bar make the mutual positions of the bore holes predetermined. Thus, the hole that is initially drilled determines the positions of the other holes in the jawbone. Hereby, it may in certain cases become apparent that these end up in a less convenient position, e.g., where there is a risk that the drilling of the hole will hit a nerve or that it will be effected at a place where the bone tissue is of poorer quality.

In other methods for prosthesis anchoring, it is previously known to fasten the lower bar to the fixtures by means of glue. In that connection, the lower bar is provided with a number of relatively large holes. When it is to be fastened to the fixtures, the lower bar is brought towards these, so that the application end of each fixture protrudes somewhat through each of the large holes in the lower bar. Next, a glue is inserted in the holes in the lower bar and when this is cured, the lower bar is fastened to the fixtures. By the fact that the holes in the lower bar are rela- tively large, there is a certain play for the positioning of the lower bar in relation to the fixtures. This means that the positions of where the drillings for the fixtures are to be recessed are not definitely predetermined by the constructive design of the lower bar. Thereby, this method does not make the same high demands for the skill of an operator as the method described in said WO 97/49351. However, the method described next above has another and more serious disadvantage. The transmission of force from the tooth prostheses to the bone in which the fixtures are anchored is effected via the glue. The compressive forces that act in the tooth prosthesis, e.g., during chewing, will be transferred from the lower bar to the respective fixture as shearing forces in the glue mass. The glue mass has by no means the same strength as metal, which is the material of the other components. Repeated compressive loads in the glue mass will eventually cause it to crack and the prosthesis anchoring will thereby become damaged. Thus, an anchoring by this method results in such a limited service life of the prosthesis anchoring that it in most cases is unacceptable. The object of the present invention is to provide a prosthesis anchoring obviating the disadvantages that are associated with the method described in WO 97/49351 , mentioned above, and which consequently permits the method to be practised by operators, for which the same high requirements of experience and skill as in the known method are not made, as well as to thereby at the same time secure that the prosthesis anchoring will be of high quality and have a long service life.

Summary of the Invention

According to the invention, a pair of components are provided for a pros- thesis anchoring system that enables a procedure where the object set up has been attained. Furthermore, a method is provided for how one of these components is produced. Finally, the invention relates to a method for prosthesis anchoring. According to the first aspect of the invention, the object set up has been attained by the fact that a prosthesis support of the type given by way of introduction comprises the special features of comprising at least one tubular element forming one of said holes and extending through an opening recessed in the frame, which runs between the first and second sides of the frame, the opening being wider than the outer contour of the tubular element, so that a space is formed between the opening and the tubular element, which space is filled by a glue adhered to the tubular element and to the limiting surface of the opening, and which tubular element has a plane end surface that is in the same plane as the planar surface on the first side of the frame.

Thus, a prosthesis support formed like this, e.g., a lower bar, has at least one hole formed by a tubular element. Each one of the holes formed by a tubular element is used to fasten the lower bar to the respective fixture. The plane end surface of the tubular element is situated on the side of the lower bar turned from the fixtures, i.e., at the side against which the upper bar is intended to abut. When the upper bar is fastened to the lower bar, the metal surface of the upper bar will abut against said plane end surface of the respective tubular element. Thereby, compressive force that is applied on the prosthesis will push against the end surface of the respective tubular element, via the upper bar. Via the tubular element, the compressive force is propagated directly inwards towards the fixture being fastened to the tubular element.

By the respective opening in the frame, there is a play for exactly where the corresponding tubular element can be located, thanks to the openings in the frame being larger than the tubular elements. The position of each tubular element within the respective opening is adapted to the position of the fixture that is to be fastened in the respective hole. Thus, in the lower bar according to the invention, the position of the anchoring holes, i.e., the tubular elements, is adapted to the position of the fixtures, instead of the other way round as in the above-mentioned WO 97/49351. Thereby, the need for drilling for the respective fixture having to be effected with great predetermined accuracy is eliminated, whereby a much simpler operational procedure, accordingly, is permitted. Thereby, the circle of operators qualified to attach a prosthesis does not need to be limited to those of great experience and skill. This gives an opportunity for the method to come to wide use. Thanks to the transmission of force from the prosthesis to the fixture taking place via solid elements, which normally are of metal, a strong and safe anchoring of long durability is furthermore attained.

According to the second aspect of the invention, the object set up is attained by the fact that a prosthesis-anchoring device of the type given by way of introduction comprises the special features that the device furthermore comprises a tubular element, and that the fastening element is arranged to detachably connect the tubular element coaxially with the application part of the fixture in such a way that engagement and disengagement may be achieved without relative turn- ing between the fixture and the tubular element.

The invented prosthesis-anchoring device constitutes a vital component in the production of a prosthesis support according to the invention, where a part of the tubular element of the device will constitute the tubular element included in the prosthesis support. Furthermore, the prosthesis-anchoring device is expedient for the fastening of the prosthesis support to the respective fixture.

Thanks to the joint between the tubular element and the fixture being of such a kind that it may be fastened and disengaged without relative turning between these elements, engagement and disengagement, respectively, of the prosthesis support is made possible. This would otherwise be impossible since the tubular element is rotationally fixed to the prosthesis support and the fixture has to be kept rotationally fixed in the bone tissue.

According to the third aspect of the invention, the object set up has been attained by the fact that a method for the manufacture of the invented prosthesis support comprises the particular steps of: - a number of tubular elements being fixed to a bearing structure

- a frame having a first and a second side being provided, which first side comprises a planar surface and which frame comprises at least one through opening running between the first and second sides of the frame, one of the openings in the frame being wider than the outer contour of a tubular element in order to enable a space to be formed between the opening and the tubular element

- the frame being brought to enter each tubular element so that each tubular element extends through one of the openings and projects past said first side - the frame being fixed in the entered position

- a glue being applied in said space and brought to solidify

- the tubular elements being detached from the bearing structure and the frame having glued-on tubular elements being removed from the bearing structure - said protruding parts of the tubular elements being machined so that the end surface of the respective tubular element is located in the same plane as said planar surface.

By the invented method, it is provided that a prosthesis support according to the invention will have anchoring holes, i.e., the holes formed by the tubular elements, which are located in adaptation to predetermined positions defined by where the tubular elements have been fixed to the substratum to which they are fastened. Therefore, the prosthesis support produced like this receives a design adapted to each specific anchoring operation and enables the procedure for prosthesis anchoring that constitutes the fundamental conceptual basis for the present invention.

According to the fourth aspect of the invention, the object set up has been attained by the fact that the method for fastening a prosthesis, given by way of introduction, comprises the particular steps of:

- a tubular element being fastened to at least one of the fixtures, - a frame having a first and a second side being provided, which first side comprises a planar surface and which frame comprises at least one through hole running between the first and second sides of the frame, at least one of the holes in the frame being wider than the outer contour of a tubular element in order to enable a space to be formed between the hole in the frame and the tubular ele- ment,

- the frame being brought to enter each tubular element so that each tubular element extends through one of the holes in the frame and projects past said side,

- the frame being fixed in the entered position, - a glue being applied in said space and brought to solidify,

- each tubular element being detached from the respective fixture, and the frame having the glued-on tubular elements being removed from the fixtures, - the protruding parts of the tubular elements being machined so that the end surface of the respective tubular element is located in the same plane as said planar surface,

- the prosthesis support having the machined tubular elements being fas- tened to the fixtures, and

- the prosthesis-holding body being fastened to the prosthesis support so that a surface of the prosthesis-holding body abuts against the machined end surfaces of the tubular elements.

By such a method for fastening a prosthesis, the disadvantages associ- ated with the previously known methods are eliminated and advantages of a type corresponding to those that have been stated above for the invented prosthesis support are gained.

According to a preferred embodiment of the invented prosthesis support, it has the shape of a deflected bar. This embodiment of the prosthesis support makes it especially suited when tooth prostheses are concerned, which is a significant application of the invention.

According to an additional preferred embodiment, the frame has a separate opening for each tubular element. This is an embodiment adapted to a procedure where the position of the drilling of each fixture is defined by a determined area, within which it is suitable to fasten the fixture and where an optimum position can be selected. Such a procedure implies a certain limitation in the selection of location. However, the limitation involves the advantage of a satisfying distribution of the position of fixtures being secured, seen from a material strength point of view. According to an alternative embodiment, an opening in the frame encloses at least two tubular elements. This is an embodiment adapted to an alternative procedure where the position of the drilling of the fixtures may be selected more freely. This is advantageous in cases where it for different reasons may be difficult to find suitable positions of the fixtures. An opening in the frame of this type may enclose two tubular elements, e.g., for two fixtures on one side of the central area of the prosthesis support. Alternatively, also the possibility of one single opening enclosing all tubular elements is comprised. Such an embodiment provides a large degree of freedom to the operator in selecting the positions of the fixtures, but it demands a good ability to be able to adjust their mutual positions so that the anchoring becomes safe.

According to an additional preferred embodiment, the prosthesis support comprises a cylindrical hole formed directly by the frame. In this case, hence one of the positions of the holes in the frame is predetermined. This hole is utilized for connection to a first fixture anchored in the bone tissue. Once a suitable position of a first fixture has been selected and the fixture has been attached, the fixture may be fastened to the prosthesis support in a predetermined position in the same, i.e., in said cylindrical hole in the frame. Therefore, for this fixture, it is not necessary to have an opening in the frame that involves a tolerance zone. The first fixture does in this case constitute a target for the areas within which the other fixtures may be fastened, i.e., the fixtures that are connected with the prosthesis support via the holes formed by the tubular elements. By, in this way, using a direction-giving first fixture the procedure is facilitated, and provides the best conditions for a well- anchored prosthesis thanks to the fact that the same also can carry tensile forces. According to an additional preferred embodiment, each opening enclosing a tubular element has an elongate shape. Since the bone in which the prosthesis support is to be fastened usually is of an elongate shape, e.g., arc shape such as in the case of a jawbone, it means that a possible suitable position of each fixture is more limited laterally than in the length extension of the bone. Thereby an elongate shape of each opening implies an adaptation to the same, and hence an optimisation of the possibility to find suitable positions of the fixtures.

According to an additional preferred embodiment, all holes through the prosthesis frame are parallel and perpendicular to the planar surface of the pros- thesis frame. A parallel orientation facilitates the procedure in the operation. Furthermore, it normally provides the safest anchoring of the prosthesis in terms of strength. This is, e.g., the case in the attachment of a dental bridge in the mandible, where occurring loads on prostheses usually are in a direction perpendicular to said planar surface of the prosthesis support. According to an alternative embodiment, at least one of the holes through the prosthesis support is such that it forms an oblique angle to the planar surface thereof. Such an embodiment may in certain cases be the most suitable, or even the only one possible. This is, e.g., sometimes the case in the attachment of a dental bridge for the upper row of teeth. The maxillary bone is not always in such a state that it is possible to attach all fixtures to the same, one or more fixtures having to be anchored in the zygomatic bone (Zygomaticum). For anatomical reasons, these will receive an oblique direction. Also in other cases where a perpendicular direction would be preferred, the possibility of having obliquely directed fixtures may facilitate the finding of suitable attachment sites for the same.

The above-mentioned preferred embodiments of the invented prosthesis support are defined in the claims depending on claim 1.

According to a preferred embodiment of the invented prosthesis-anchoring device, the fastening element is a screw, and the fixture has a centric drilling with a thread complementary with the thread of the screw at the application end thereof. By the fact that the interaction of the fastening element and the fixture thereby consists of a screw joint, it is in an easily manoeuvrable way attained that the tubular element can be detached from and locked to, respectively, the fixture, without the tubular element needing to be turned in relation to the fixture. According to another preferred embodiment, the tubular element is circular and internally provided with an inwardly directed flange having a centric hole, the flange being situated a short distance from one end of the tubular element and long distance from the other end thereof, which hole has a diameter that allows passage of the threaded part of the screw but prevents passage of the head thereof. The construction entails a simple realization of the connection between the tubular element and the fixture. In that connection, the tubular element is placed on the application end of the fixture and the screw is inserted in the tubular element from the opposite end so that the threaded part of the screw passes the hole and in, towards the drilling of the fixture. The screw may then be turned by means of a tool that is inserted through the free end of the tubular element and so that it is screwed into the drilling.

According to another preferred embodiment, the application part of the fixture has a cylindrical portion that has a larger diameter than the inner diameter of the tubular element, and the axially outermost end of the application part has a portion having a maximum dimension laterally that is smaller than the inner diameter of the tubular element. This facilitates to place the tubular element on the application end of the fixture correctly directed for tightening the same in the fixture. According to another preferred embodiment, the cylindrical portion of the application part has the same diameter as the outer diameter of the tubular element. Thereby, it is attained that the screwed-together device receives a uniform even outside without any edges that may cause irritation to the person that carries the prosthesis.

According to another preferred embodiment, the tubular element has a length of at least 10 mm. Thereby, it is ensured that the length is sufficient for extending through the frame that together with the tubular element and the glue form a prosthesis support according to the invention, which is necessary in order to bring about such a prosthesis support.

According to another preferred embodiment, the fixture, the fastening element and the tubular element are all of metal. This is advantageous from a material strength point of view.

According to another preferred embodiment, the fixture is made of tita- nium. It has become apparent that bone tissue has a great ability to accept presence of elements made of titanium. Furthermore, titanium has a particular quality to interact with bone tissue so that adhesion arises between them, so-called osseointeg ration, which is essential for a strong anchoring of the fixture.

The above-mentioned preferred embodiments of the invented prosthesis- anchoring device are defined in the claims depending on claim 10.

According to another preferred embodiment of the invented method for the manufacture of a prosthesis support, the bearing structure comprises a number of fixtures anchored in a common substratum, each tubular element being fastened to a fixture. Since a prosthesis support of this type is intended to be fastened to fixtures in use, it is advantageous to form the bearing structure as such already in the manufacture. This decreases the risk of mistakes and increases the possibility of good precision.

According to another preferred embodiment, the frame is fixed in the entered position by being fastened in a fixture anchored in the substratum. Thanks to the fixation of the frame being carried out in this way, it is facilitated to have the same placed in a correct position in relation to the tubular elements, since the substratum then constitutes a common reference for the position of the fixture utilized for fixation as well as for the fixtures to which the tubular elements are fastened. According to another preferred embodiment, said substratum consists of a person's bone tissue. By the fact that the fixtures that are used for the manufacture of the frame thereby also are the same to which the finished manufactured prosthesis support is to be anchored, the best feasible conditions for a good precision in this anchoring is thereby provided.

The above-mentioned preferred embodiments of the invented method for the manufacture of a prosthesis support are defined in the claims depending on claim 18.

According to a preferred embodiment of the invented method for fastening a prosthesis, this is performed by means of a prosthesis support according to the present invention and by means of a prosthesis-anchoring device according to the present invention.

According to another preferred embodiment of this method, the same comprises the measures that are mentioned for the method in the production of a prosthesis support according to the present invention.

By the preferred embodiments of the invented method for fastening a prosthesis, advantages are gained of a type corresponding to those gained by the devices and methods according to the other aspects of the invention and which have been accounted for above. The invention is explained in more detail by the subsequent detailed description of advantageous embodiment examples of the same while referring to the accompanying drawings.

Brief Description of the Figures Fig. 1 is a view from above of a template used in a method according to the invention.

Fig. 2 is a longitudinal section through a fixture used in a method according to the invention.

Fig. 3 is a longitudinal section through a prosthesis-anchoring device according to the invention.

Fig. 4 is a view from above of a frame used in a method according to the invention.

Fig. 5 is a view from above of a prosthesis support according to the invention. Fig. 6 is a section along the line VI-VI in fig. 5.

Fig. 7 is a section corresponding to that of fig. 6, and which illustrates a prosthesis support according to the invention having an affixed dental bridge. Fig. 8 is a view corresponding to that of fig. 5, and illustrating an alternative embodiment example.

Description of Advantageous Embodiment Examples

The understanding of the invented prosthesis support and other aspects of the invention and the advantages associated therewith are probably most clearly seen by a description of the procedure in the attachment of a prosthesis to a patient by means of the invented prosthesis support and the invented prosthesis- anchoring device. The example is related to fastening a dental bridge to the mandible of a patient. In a first step, a preliminary indication is made. In that connection, an adjusting template is used, illustrated in fig. 1 , which shows the template 1 in a view from above and placed above the mandibular bone A of a patient. The template has a handle 2 and an arc-shaped fitting-in part 3. The arc shape is adapted to substantially correspond with a mandibular bone. The fitting-in part is provided with a central hole 4 of a small diameter and two laterally located openings 5 of comparatively large dimensions. By means of the template 1 , an operator may measure a suitable position of where a drilling for a first fastening fixture can be effected and at the same time ensure that the two laterally located openings 5 in that connection will be located in such a way that there, within the contour of each opening 5, is a space where holes for other fixtures may be drilled, without the drilling landing up in a nerve or in poor bone material. Thus, the operator has the freedom of displacing the template to some extent in various directions or turning it somewhat in order to find an optimal position. When this has been achieved, a mark is made in the jawbone through the central hole 4 as a guidance for the sub- sequent drilling operation.

In that connection, the side openings 5 primarily serve to give information that satisfying points of fastening for laterally located fixtures exist when using the selected position of the central hole. In this step, it is also possible to make a mark for a suitable place to drill within the respective laterally located opening 5. However, this is not essential.

In a second step, the template is removed, and a hole is drilled in the jawbone at the mark made through the central hole 4 of the template. In the drilled hole, a first fixture is screwed in.

Next, holes for the laterally located fixtures are drilled in the jawbone. Marking of where the holes are to be drilled may have been made in the first step in connection with the making of the hole marking of the central hole. Alternatively, markings may be made in this step following the screw-in of the first fixture. In the latter case, a new template is fastened to the first fixture. This template has also laterally located openings of corresponding sizes and may possibly consist of the frame that is to form the prosthesis support, i.e., the lower bar. Locations of the laterally located holes are marked at a suitable site within the areas of the bone that are exposed through the laterally located openings. When the frame of the lower bar is used as a template, a gauge may possibly be used in order to indicate that the marking is made at a sufficient distance from the edge of the respective laterally located opening so that a tubular element attached in a later stage may pass freely through the hole. In case a separate template is used in the making of the marks, the corresponding margin may be brought about by the fact that the laterally located openings of the separate template are smaller than the corresponding openings in the frame of the lower bar.

Following the making of the marks of the laterally located fixtures, holes are drilled for the same in the jawbone at the marked spots. This may be carried out free-hand or by means of a drill template. Next, a fixture is screwed into each bore hole. On each one of the two laterally located fixtures, an extension in the form of a tubular element is fastened.

In fig. 2, a fixture of the type that is anchored in the jawbone and to which the frame 21 of the lower bar is fastened is illustrated in a longitudinal section. The fixture 6 consists of an anchoring part 7 and an application part 8. The length thereof is approx. 20 mm. The anchoring part is approx. 15 mm in length and has a diameter of 3-4 mm. It is threaded along the entire length thereof and has a chamfering 25 and slots 26 at the innermost end thereof for facilitating the screw- in. The fixture is screwed into a hole in the bone having a diameter corresponding to the bottom diameter of the thread, a thread being formed in the surrounding bone material A. The fixture is suitably made from titanium for achievement of adhesion in the bone material, so-called osseointegration. The application end of the fixture has a cylindrical portion 10, which is provided with a hexagon-shaped portion 11 at the outer end thereof. Furthermore, the application end of the fixture has a threaded drilling 12 for interaction with a fixing screw 13. The fixing screw 13 has a head 14 having an inner hexagon 15 for application of a screw tool. By means of the screw 13 extending through a hole 19 in the frame 21 of the lower bar, the latter is fastened in the fixture 6.

The frame 21 has a recess 30 on the bottom side thereof, arranged to enclose the hexagon-shaped portion 11 of the fixture. The fixture illustrated in fig. 2 is the centrally placed one.

In fig. 3, it is shown how one of the laterally located fixtures 6a is fastened to a tubular element 16. The fixture 6a and the fixing screw 13a are of the same type as the centrally placed fixture shown in fig. 2. By means of the fixing screw 13a, the fixture 6a is fastened to a tubular element 16 having the same outer diameter as the cylindrical portion 10a of the fixture. At the end located closest to the fixture 6a, the tubular element has an inwardly directed flange 17 having a centre hole 18. When the tubular element is to be fastened to the fixture, the tubular element is placed with one of the ends thereof against the end of the fix- ture in the position shown in fig. 3, the inner end of the tubular element enclosing the hexagon-shaped portion 11a of the fixture. Next, the fixing screw 13a is brought down through the centre hole 18 in the flange 17 and into the threaded drilling 12a of the fixture, after which the screw is turned into the thread by means of a turning tool applicable in the inner hexagon 15a. The inside of the moving element 16 is intended to form a hole 31 through the completed prosthesis support.

In a third operation step, the frame 21 is again fastened to the lower bar at the centrally placed fixture, see fig. 2. The frame 21 is shown in a view from above in fig. 4. It has an arc shape adapted to the shape of the jawbone and is provided with a central hole 19 having a diameter exactly adapted for leading through a fixing screw 13 and is furthermore provided with two laterally located openings 20, which are considerably larger.

In fig. 5, the frame 21 is shown in a view from above in the position the same assumes when the same in this step is screwed-on to the central fixture. Thereby, the central hole of the fixture in the figure is concealed by the head 14 of the central fixing screw. In each of the laterally located openings 20, the tubular element 16 fastened to the respective laterally located fixture is seen. In fig. 6, a section is shown along the line VI-VI of fig. 5. As can be seen, the tubular element 16 has a length sufficiently large for the tubular element to extend through the opening 20 and past the planar surface 22 of the frame 21. In fig. 6, it is also seen that the frame 21 on the side thereof facing the jawbone of the patient is provided with a sealing jointing 23, which may be made from rubber and is pasted on to the frame. The sealing jointing is penetrated by the tubular element 16 when the frame is screwed-on to the central fixture.

When the frame 21 is fastened to the central fixture and has assumed the position illustrated in figs. 5 and 6, the space in the opening 20 between the tubular element 16 and the edges of the opening is filled up by a glue 28. This may be a two-component adhesive, e.g., of the type that is marketed under the trade mark G C Composite Resin Unifill Core (Trademark). Then, the glue is allowed to cure. When the glue has cured, step four follows. In that connection, all fixing screws 13 are loosened, after which the lower bar 27, formed by the frame 21 and having the glued-on tubular element 16, is removed from the fixtures. Next, the parts of the tubular element 16 protruding through the top side of the lower bar 27 are ground down so that the end surfaces of the tubular elements will be located in the same plane as the planar top side 22 of the lower bar 27. Possible excess glue on the top side of the lower bar is also ground away at the same time. The sealing jointing 23 on the bottom side is removed, and then the lower bar is fastened to the fixtures again. In a fifth and final step, an upper bar having tooth prostheses may now be fastened to the lower bar.

In fig. 7, a section corresponding to that of fig. 6 is illustrated, where a prosthesis-holding body consisting of an upper bar 24 having tooth prostheses 29 is fastened to the lower bar 27. By the fact that the outer ends of the tubular ele- ments 16 are located in the same plane as the top side 22 of the lower bar 27, the upper bar with the bottom side thereof will be in contact against the outer end of the respective tubular element. Compressive forces from the tooth prostheses will thereby be transferred from the upper bar 24 via the tubular element 16 to the fixture, there being a direct metal contact in the entire path of the force transmission. The upper bar 24 is fastened in a conventional way to the lower bar 28 by means of a number of screws extending through holes in the upper bar and into drillings on the top side of the lower bar. However, this is not illustrated.

In fig. 8, an alternative embodiment of the frame is illustrated in a view cor- responding to that of fig. 5. In this case, the openings 20 are considerably larger and two tubular elements 16 are arranged in each opening 20.

The procedure described above implies that, during the course of the pro??cess, a prosthesis support is produced, i.e., the lower bar that may be defined as stated in claim 1 and that is an essential component in order to apply the disclosed procedure.

Above, a practice for the application of a dental bridge in the mandible of a patient has been disclosed. However, it is also applicable to a dental bridge in the maxilla, or in the attachment of a prosthesis support in another bone.

Claims

1. Prosthesis support (27) intended for carrying one or more prostheses, which support comprises a frame (21) having a first side and a second side, which first side has a planar surface (22) and which prosthesis support (27) is provided with a plurality of through holes (19, 31) running between the first and second sides of the frame, characterized in that the prosthesis support comprises at least one tubular element (16) forming one of said holes (31) and extending through an opening (20) recessed in the frame (21), which opening runs between the first and second sides of the frame, each opening (20) being wider than the outer contour of the tubular element (16) so that a space is formed between the opening (20) and the tubular element (16), which space is filled by a glue (28) adhered to the tubular element (16) and the limiting surface of the opening (20), and which tubular element has a planar end surface that is located in the same plane as the planar surface (22) on the first side of the frame (21).

2. Prosthesis support according to claim 1 , characterized in that the same is in the form of a deflected bar.

3. Prosthesis support according to any one of claims 1 or 2, characterized in that the frame has a separate opening (20) for each tubular element (16).

4. Prosthesis support according to any one of claims 1 or 2, characterized in that at least one opening (20) in the frame (21) encircles at least two tubular elements (16).

5. Prosthesis support according to any one of claims 1-4, characterized in that the same comprises a cylindrical hole (19) that is formed directly by the frame (21).

6. Prosthesis support according to claim 5, characterized in that the cylindrical hole (19) formed by the frame (21) is located in a central area of the prosthesis support (27) and that at least one tubular element (16) is arranged on each side of the hole (19) located in the central area.

7. Prosthesis support according to any one of claims 1-6, characterized in that each opening (20) enclosing a tubular element (16) has an elongate shape.

8. Prosthesis support according to any one of claims 1-7, characterized in that all holes (19, 31) through the prosthesis support (27) are parallel, and perpen- dicular to said planar surface (22).

9. Prosthesis support according to any one of claims 1-7, characterized in that at least some hole (19, 31) through the prosthesis support forms an oblique angle to said planar surface (22).

10. Prosthesis-anchoring device for use in the fastening of a prosthesis support in the bone tissue of a patient, which device comprises a fixture (6a), and a fastening element (13a), which fixture (6a) has an application part (8a) and an anchoring part (7a) provided with a screw thread, which anchoring part is arranged for screw-in into the bone tissue (A) of a patient, characterized in that the device furthermore comprises a tubular element (16), and that the fastening element (13a) is arranged to detachably connect the tubular element (16) coaxially to the application part (8a) of the fixture (6a) in such a way that engagement and disengagement may be brought about without relative turning between the fixture (6a) and the tubular element (16).

11. Prosthesis-anchoring device according to claim 10, characterized in that the fastening element is a screw (13a) and that the fixture (6a) has a centric drilling (12a) at the application end thereof, which drilling is provided with a thread complementary to the screw thread.

12. Prosthesis-anchoring device according to claim 11 , characterized in that the tubular element (16) is circular and at the inside provided with an inwardly directed flange (17) having a centric hole (18), the flange (17) being arranged at a short distance from one end of the tubular element and at a long distance from the other end of the tubular element and which hole (18) has a diameter allowing passage of the threaded part of the screw (13a) but preventing passage of the head (14a) thereof.

13. Prosthesis-anchoring device according to any one of claims 10-12, characterized in that the application part (8a) of the fixture has a cylindrical portion

(10a), which has a larger diameter than the inner diameter of the tubular element (16) and that the axially outermost end of the application part has a portion (11a) having a maximum dimension laterally that is smaller than the inner diameter of the tubular element (16).

14. Prosthesis-anchoring device according to claim 13, characterized in that the cylindrical portion (10a) of the application part has approximately the same diameter as the outer diameter of the tubular element.

15. Prosthesis-anchoring device according to any one of claims 10-14, characterized in that the tubular element (16) has a length of at least 10 mm.

16. Prosthesis-anchoring device according to any one of claims 10-15, characterized in that the fixture (7a), the fastening element (13a), and the tubular element (16) are all made from metal.

17. Prosthesis-anchoring device according to claim 16, characterized in that at least the fixture (7a) is made from titanium.

18. Method for the manufacture of a prosthesis support according to any one of claims 1-9, characterized in that

- a number of tubular element are fixed to a bearing structure - a frame having a first and a second side is provided, which first side comprises a planar surface and which frame comprises at least one through opening running between the first and second sides of the frame, at least one of the openings being wider than the outer contour of a tubular element in order to enable a space to be formed between the opening and the tubular element - the frame is brought to enter each tubular element so that each tubular element extends through one of the openings and projects past said first side

- the frame is fixed in the entered position

- a glue is applied in said space and brought to solidify

- the tubular elements are detached from the bearing structure and the frame with glued-on tubular elements is removed from the bearing structure

- said protruding parts of the tubular elements are machined so that the end surface of the respective tubular element is located in the same plane as said planar surface.

19. Method according to claim 18, characterized in that the bearing structure comprises a number of fixtures anchored in a common substratum, each tubular element being fastened to a fixture.

20. Method according to claim 19, characterized in that the frame is fixed in the entered position by being fastened in a fixture anchored in the substratum.

21. Method according to claims 19 or 20, characterized in that the substratum consists of a person's bone tissue.

22. Method for fastening a prosthesis to a number of anchored fixtures, wherein a prosthesis support is fastened to said fixtures and a prosthesis-holding body is fastened to the prosthesis support characterized in that

- a tubular elemerrt is fastened to at least one of the fixtures,

- a frame having a first and a second side is provided, which first side comprises a planar surface and which frame comprises at least one through opening running between the first and second sides of the frame, at least one of the openings being wider than the outer contour of a tubular element in order to enable a space to be formed between the opening and the tubular element,

- the frame is brought to enter each tubular element so that each tubular element extends through one of the openings and projects past said side,

- the frame is fixed in the entered position,

- a glue is applied in said space and brought to solidify

- each tubular element is detached from the respective fixture, and the frame having the glued-on tubular elements is removed from the fixtures, - the protruding parts of the tubular elements are machined so that the end surface of the respective tubular element is located in the same plane as said planar surface,

- the prosthesis support having the machined tubular elements is fastened to the fixtures, and - the prosthesis-holding body is fastened to the prosthesis support so that a surface of the prosthesis-holding body abuts against the machined end surfaces of the tubular elements.

23. Method according to claim 22, characterized in that the same is practised by means of a prosthesis support according to any one of claims 1-10 and by means of at least one prosthesis-anchoring device according to any one of claims 11-17.

24. Method according to claim 23, characterized in that the same comprises the measures for the manufacture of a prosthesis support that are stated in any one of claims 18-21.