An assembly comprising at least one fixing device to be attached to an implant

The invention relates to an assembly comprising at least one fixing device to be attached to an implant, as well as a bar to be connected to the fixing device.

The invention further relates to a fixing device as well as to a bar for use in such an assembly.

From DE-42.11.561-A1 an assembly is known for attaching a bar to an implant by means of the fixing device. In the known assembly, the fixing device is fixed to the implant by means of a screw. The fixing device is provided with a ball cavity for receiving a ball-shaped bar end, which is telescopically movable within a bar sleeve. The bar can be adjusted relative to the fixing device and the implant by means of such a ball joint. Another bar end, which is likewise telescopically movable within said sleeve, is fixed to another fixing device in an identical manner.

With the known assembly, different bars must be used for bridging a relatively large distance, because a single bar can only be stably extended up to a maximum length between two fixing devices. Furthermore, it is not possible with the known assembly to form extensions by means of the bar.

The object of the invention is therefore to provide an assembly that can be built up in a simple manner.

This object is accomplished with the bar according to the invention in that the fixing device is provided with an element which can be annularly fitted over the bar.

The element can be attached to the bar at any longitudinal position thereof, and minor positioning corrections relative to the implant can be carried out upon attaching the element to the bar. Because of this possibility to carry out such positioning corrections with the element that annularly surrounds the bar, less stringent requirements may be made with regard to the positioning accuracy of implants. Furthermore, by annularly fitting the element over a bar, for example by sliding the bar through the element, is a very simple operation, it even becomes possible to attach the bar to the element of the fixing device in the patient's mouth. Preferably, the bar, once it has been attached to the element, is entirely or substantially entirely enclosed by the element. Furthermore it is possible to use a

relatively long bar, in which case the bar is attached to an implant in the centre thereof via the element of the fixing device, for example for guiding the bar. It is moreover possible to provide an extension by means of a bar that is guided by the element. An extension is a free end of the bar, which bar is attached to at least two elements. Said end of the bar has been or is bent so that it can receive a dental prosthesis. Extensions are used for minimising or even excluding any tilting of a dental prosthesis attached to the assembly. Because a relatively long bar is provided, comparatively few operations are required for assembling the assembly which extends over a relatively large distance. A single bar may even follow a contour of a jaw.

The element can be annularly fitted over any bar of any shape in the longitudinal direction thereof and, once fitted over the bar, the element surrounding the bar can take the shape of said bar.

The term bar is understood to mean a retention bar, which normally extends between two substantially vertically extending implants in the jaw, to which bar a fixing element of a prosthesis or orthesis can be attached.

Preferably, all parts of the assembly are biocompatible, so that they will not cause any damage or discomfort in a patient's body, in which said parts will remain for relatively long periods of time.

A special preferred embodiment of the assembly according to the present invention is characterised in that the element can be deformed against spring force from a first position, in which the bar can be positioned in radial direction in the element, to a second position, in which said element annularly encloses the bar.

Because the element is deformable in this manner, the bar can be attached to the element of the fixing device in a relatively simple manner. In the second position, the bar is secured in the annular element in a very stable manner under the influence of said spring force.

Another embodiment of the assembly according to the present invention is characterised in that the element has a first end and a second end, which ends are connected to legs, by means of which said ends can be connected together so as to enable the element to annularly enclose the bar.

The legs, which are each attached to an end of the element, make it possible to fit the element tightly round the bar, as a result of which a strong

connection is effected, so that dental prostheses and/or ortheses can stay in a patient's mouth for a prolonged period of time.

Another embodiment of the assembly according to the present invention is characterised in that the element is provided with a contact surface on the inner side, against which the bar can be positioned, which contact surface is provided with an anti-rotation surface.

In this way it is easy to realise a connection in which the bar can hardly rotate, if at all, within the ring. The contact surface preferably comprises an anti-rotation surface that increases the friction between the ring and the bar, for example a coating or the like. The contact surface may also be provided with a suitable relief, for example consisting of ribs.

Yet another embodiment of the assembly according to the present invention is characterised in that the fixing device further comprises a sleeve, which can preferably be screwed down on an implant, whilst the legs can be fixed in place within the sleeve by means of a curing filler.

This manner of fixation provides many adjusting possibilities or degrees of freedom for definitively adjusting the bar with respect to the implant. Said filler may be a synthetic material or filler or a suitable dental cement. The legs are firmly fixed to the sleeve by means of the hardened filler. In this way a solderless biodynamic connection between the implant and the bar is provided, which is easy to fit, even in the patient's mouth.

The sleeve may be internally provided with a surface enlarged by means of ribs or another type of relief, which enlarges the bonding area between the curing filler and the sleeve.

If desired, an abutment may be provided between the sleeve and the implant. By means of an abutment, the sleeve can be used with all known types of implants.

Another embodiment of the assembly according to the invention is characterised in that the bar is circumferentially provided with a recess, in which the element can be fitted.

Such a recess can be formed in the bar in a simple manner by means of a punch. By means of such a punched recess, a stabler connection between the bar and the element is obtained in a simple manner. Preferably, the element accurately fits the recess, so that the element cannot slide over the bar,

because the bar abuts against the edges of the recess.

Yet another embodiment of the assembly according to the present invention is characterised in that the recess is provided with a contact surface against which the element can be positioned, which contact surface is provided with an anti-rotation surface.

Such a surface secures the bar against rotation. By providing the surface with a friction-increasing coating or with ribs, rotation of the bar with respect to the element of the fixing device is prevented in a simple manner. It is very advantageous, of course, if the contact surface of the recess of the bar corresponds to the contact surface of the element as regards the shape thereof, in which case the shape of the contact surface of the recess and that of the contact surface of the element interlock. The anti-rotation surface might be formed in the bar simultaneously with the recess by means of said punch. Furthermore it is possible to use a die for forming the anti-rotation surface.

Another embodiment of the assembly according to the invention is characterised in that the bar is provided with a liner of plastic material.

A liner of plastic material makes it possible to attach a prosthesis to the bar by means of a snap connection, without using additional means of attachment. Said snap connection can furthermore be adjusted in a simple manner by applying a curing adhesive or the like to the inner side of the prosthesis, so that a strong connection between the prosthesis and the bar is realised. Preferably, a longitudinally extending core of the bar is made of a metal so as to increase the strength of the bar. Said metal may be a flexible metal.

Yet another embodiment of the assembly according to the present invention is characterised in that the bar has a U-shaped, a circular, a trapezoidal or an oval sectional shape.

A bar section that is especially preferred in connection with the above-described snap function is an oval section. The advantage of a U-shaped section and a trapezoidal section of the bar is that such a section prevents rotation of the bar within an annular element that tightly surrounds the bar. It is also possible to use a bar having a round or circular section in the assembly according to the invention.

The invention will now be explained with reference to the appended figures, in which:

Figure 1 is a schematic front view of an assembly according to the present invention, which is attached to an implant;

Figure 2 is a sectional view I-l of the assembly according to the present invention that is shown in figure 1 ;

Figures 3a-c show various views of a sleeve of a fixing device of the assembly according to the present invention;

Figures 4a-c show various views of an element and the legs connected thereto of a fixing device of the assembly according to the present invention;

Figure 5 shows various views of differently shaped bars;

Figures 6a and 6b are schematic views of the assembly according to the present invention attached to two implants and to implants implanted in a patient's jaw, respectively.

Like parts are provided with the same numerals in the various figures.

Figure 1 shows a front view of an assembly 10 according to the invention attached to an implant 1 for placing a dental prosthesis (not shown). Normally, the implant 1 will be fixed in the lower or the upper jaw. Such implants 1 are known per se and consequently they will not be discussed in detail herein.

The assembly 10 according to the invention comprises a fixing device 3, which comprises a sleeve 5 and an element 7. The assembly 10 further comprises an oval bar 13, over which dental prostheses can be fitted. The bar 13 is provided with a recess 15, which extends circumferentially around the bar 13.

The element 7 of the fixing device 3 has a first end 19 and a second end 21 , which ends 19, 21 are connected to legs 9, 11. The legs 9, 11 can be secured in the sleeve 5.

The sleeve 5 is provided with a notch 12 at the front side. The notch has a dimension sufficiently large to enable the legs 9, 11 to move therethrough in order to fix the element 7 and the bar 13 in place at the desired height with respect to the implant 1.

Figure 2 shows a sectional view I-l of the assembly 10 that is attached to an implant 1 in figure 1. The bar 13 of the assembly 10 is illustrated in a dotted line in figure 2.

The element 7 can be deformed against spring force from a first

position (not shown), in which the bar 13 can be positioned or snapped into the element 7 in radial direction, to a second position (shown in figures 1 and 2), in which the bar is annularly enclosed by the element 7.

The inner contact surface 17 of the element 7 is provided with a knurled surface so as to realise a strong connection with the similarly knurled contact surface (not shown) of the recess 15 of the bar 13 in order to thus ensure that the bar 13 cannot rotate within the element 7 surrounding the bar 13. The element 7 is furthermore protected against displacement in the longitudinal direction of the bar 13 by the edges of the recess 15.

By reducing the opening of the element 7, through which the bar 13 extends, in the second position of the element 7 by means of the legs 9, 11 , the element 7 is pressed more tightly against the bar 13.

The sleeve 5 is fixed to the implant 1 by means of a screw 23. An inner wall 24 of the sleeve 5 is furthermore provided with a relief in the form of rectangular knurls.

The sleeve 5 is furthermore provided with a centrally disposed circular wall 25 extending from a bottom 26 of the sleeve 5 between the legs 9, 11 disposed within the sleeve 5. The surface of the wall 25 facing towards the inner wall 24 of the sleeve 5 is likewise provided with a relief.

Via the wall 25, the screw 23 can be reached at all times with suitable tools (not shown), for example for unscrewing and replacing the sleeve 5 or for making an adjustment, for example placing an abutment between the sleeve 5 and the implant 1 (not shown).

To fix the legs 9, 11 in place within the sleeve, the sleeve 5 is filled with a curing filler. In this way the legs 9, 11 and the bar 13 connected thereto via the element 7 are fixed in place within the sleeve 5, whilst the sleeve 5 itself is fixed to the implant 1 by means of the screw 23.

Before the sleeve 5 is filled with a filler, the legs 9, 11 are positioned in the sleeve 5, using auxiliary means (not shown), in such a manner that the element 7 and the bar 13 are in the desired position for placing a prosthesis or the like on the bar 13. While the filler is hardening, the legs 9, 11 may be further adjusted with the aid of said auxiliary means. Said hardening can be accelerated by means of suitable equipment (not shown) which is known per se.

To adjust the desireti height of the bar 13 relative to a lower or an

upper jaw, the sleeve 5 is provided with the above-described notch 12. It is even possible to position the annular element 7 at substantially the same height as the sleeve 5, with the legs 9, 11 extending outwards through the notch 12.

The notch 12 may be sealed during said filling of the sleeve 5. The filler may furthermore be a paste or the like, which has a viscosity such that it will not flow out of the sleeve 5 via the notch 12, so that the notch 12 need not be sealed.

The relief on the walls 24, 25 functions to enlarge the area of the walls 24, 25 that face towards the interior of the sleeve 5, so that a larger bonding area will be available for the curing filler, as a result of which the adherence of the filler to the sleeve 5, and thus the fixation of the legs 9, 11 within the sleeve 5, is improved.

Figures 3a-c are a plan view, a side view and a front view, respectively, of the sleeve 5.

In the plan view (figure 3a) the shape of the sleeve 5 can be clearly distinguished. The circular shape of the sleeve 5 has been selected so that on the one hand the legs 9, 11 can be readily positioned within the sleeve 5, whilst on the other hand the internal volume of the sleeve 5 is relatively limited, so that comparatively little filler is needed for filling the sleeve 5. The figure furthermore clearly shows how the wall 25 bounds a space 27.

The side view (figure 3b) shows the bottom 26 of the sleeve 5. The bottom 26 is provided with an opening 29 for fixing the sleeve 5 to the implant 1. The opening 29 can be reached via the space 27 bounded by the wall 25. The sleeve 5 can be connected to the implant 1 by screwing the screw 23 into the implant 1 via the space 27.

In the front view (figure 3c) the wall 25, viewed through the notch 12, is shown without a relief for the sake of clarity.

The sleeve 5 is preferably made of a biocompatible metal, for example gold or titanium, or of high-quality ceramic materials.

Figures 4a-c are a plan view, a first side view and a second side view, respectively, of the fixing device 3 comprising the element 7 and the legs 9, 11.

In the plan view (figure 4a), the (circular) shape of the lower parts 28 of the legs 9, 11 is shown, which parts 28 can be fixed in place within the sleeve 5 by means of the filler.

The side views (figures 4b and 4c) show the element 7 and the legs 9, 11 as also shown in the preceding figures. The legs 9, 11 comprise the lower parts 28 as well as the upper parts 30, with the lower parts 28 including an angle α with the upper legs 30.

The legs 9, 11 are preferably made of a material such that the angle α can be varied before the filler is introduced into the sleeve 5, or in any case before it has hardened, for fixing the element 7, and thus the bar 13, in the desired position.

The element 7 and the legs 9, 11 are preferably made of a biocompatible material.

Figure 5 shows a number sections of a bar 13a-e according to the invention, among which an oval section 13b, a trapezoidal section 13c and a U- shaped section 13d of the bar 13. The figure furthermore shows a bar 13 having a circular section 13a. The bars 13a-d are provided with a recess 15, which can be formed in the bar 13 by means of a punch (not shown) or a die (not shown). Furthermore, the contact surface 32 of the recess 15 may be provided with a relief, for example consisting of ribs in the illustrated example, by means of said punch, so that the contact surface 17 of the element 7 that is provided with a relief can be fixed in the recess 15 of the bar 13 in such a manner that it is secured against rotation.

The bar 13e has an oval section and comprises a metal core 31. The metal core 31 gives the bar 31 rigidity, which property can be combined with the good snap connection properties of a liner 33 of plastic material for attaching a prosthesis or an orthesis to the assembly 10. A recess 15 provided with a contact surface 32 may also be formed in the bar 13e by means of said punch.

Figure 6a is a schematic view of the assembly 10 according to the present invention, which is attached to an implant 1 , whilst a prosthesis fixing device 35 is connected to the bar 13 of the assembly 10.

In figure 6b the assembly 10 is attached to implants 1 placed in a patient's lower jaw 37, whilst a fixing device 35 is connected to the bar 13 for placing a prosthesis (not shown).

The bar 13 extends through four elements 7 and may even be guided along a curved path by means of the elements 7 that annularly surround the bar 13.

The bar 13 as shown comprises free ends indicated by

extensions 39. Said extensions 39 function to prevent a dental prosthesis (not shown) attached to the bar 13 from tilting inwards under the influence of forces exerted on the dental prosthesis. An extension 39 is an end of the bar which can be bent and which, once bent, includes an angle with a part of the bar 13 that extends between two middle implants. In the illustrated example of figure 6b, said tilting is also prevented by the outer fixing devices 3 attached to the implants 1. If only two implants 1 are present in the jaw 37, the assembly 10 according to the invention may be provided with extensions 39 to prevent tilting of a dental prosthesis to be attached to the assembly 1,0.

When using the assembly 10, only one bar 13 needs to be used for covering any distance in a patient's set of teeth.

Furthermore, an abutment (not shown) may be fitted between the sleeve 5 and the implant 1. This may be desirable on the one hand with a view to positioning the sleeve higher in the mouth, but on the other hand the abutment may also function as a universal intermediate element, making it possible to attach the sleeve 5 to any implant 1 that is known and that may be developed yet. It is also possible to manufacture different types of sleeve 5 for different types of implants, of course.

The bar 13 may be passed through an annular, closed element which cannot be deformed from the first position to the second position in the manner described above.

It is furthermore possible to secure the legs 9, 11 to a sleeve that is to be fixed to an implant by means of a clamping force rather than by using a filler. It is for example possible to secure the legs 9, 11 to the sleeve by means of a snap connection.

Furthermore, it is possible to use an embodiment in which the fixing device comprises a sleeve provided with an integrated annular element, which can be annularly slid over a bar and be stably attached thereto.

The walls 24, 25 may be provided with any retention-increasing surface, i.e. any surface that provides an improved or a stronger bond between the filler and the wall.

Furthermore, different fixing devices 3 may be used for fixing a single bar 13.