SE468339B - DEVICE FOR PROMOTING GROWTH OF BONE TAPE AND DEVICE FOR PROCEDURAL ANCHORING OF AN IMPLANT - Google Patents

Description

CN CC) (JJ (JJ 10 15 20 25 30 35 2 In order to enable the use of dental bridges when the bone is so strongly resorbed that fixtures cannot be anchored therein one must recreate the jawbone to such an extent that it will be possible to anchor fixtures therein.

One known way to do this is to transplant one piece of the patient's iliac crest or ribs to the jaw. The the transplanted bone piece is processed to fit jaws. Then it is screwed in with the help of fixtures the existing jawbone, after which the mucosa is applied and sewn tight. In the jaw thus restored, one can then prosthesis attached. In addition to the fact that this method is expensive, the they and expose the patient to some discomfort (in particular elderly people may have postoperative hip problems) it also has the disadvantage that the transplanted bone sorbed gradually.

Another known way to recreate the jawbone is to build up the resorbed jawbone using non-resorbed bone-like materials, for example hydroxylapatite. The- technology is described, for example, in the article “Projection of alveolar ridge deficiencies with nonresorbable hydroxyl- apatite ", in Journal of the American Dental Association, vol 105, December 1982, pp. 993-1001. There are also areas other than dentistry problems with recovering skeletal parts that have lost theirs original form. After a traffic accident, for example need to restore crushed and depressed skeletal parts in the face and in the treatment of skeletal cancer one is forced sometimes to operate off parts of the skeleton, which parts may need to be replaced.

An object of the present invention is to solve the above-mentioned problems by designating a device which promotes bone tissue growth.

Another object of the invention is to achieve a device, by means of which an improved anchoring of an implant in bone tissue can be provided. 10 15 20 25 30 35 3 The objects of the present invention are achieved with by means of devices according to the appended claims.

In the following, embodiments of the invention are described. with reference to the accompanying drawings, in which Fig. 1 is a perspective view showing a device according to according to the invention, which is particularly suitable for get an improved anchoring of dental implants; Fig. 2 is a cross-sectional view showing a device Fig. 1 mounted on a dental implant in a jaw; and Fig. 3 is a sketch showing a part of a face with a example of a device according to the invention for providing growth of the cheekbone.

Fig. 1 shows a device for producing a improved anchoring of an implant in bone tissue. The shown device is particularly suitable for fixtures, which used to permanently anchor dentures in the jaw net.

The device shown, which is generally denoted by reference numeral 1, is substantially in the form of a cap.

Its lower periphery 2 is rounded and in the embodiment shown substantially circular. The cap can be half- spherical or, as in the figure truncated hemispherical. On top on the pen of the cap there is a centrally located opening 3.

The cap is made of a tissue compatible and inert material, preferably titanium. Other examples of suitable materials are ceramic materials, for example lit, steel, plastic and hydroxylapatite. The thickness of the cap is preferably so small in relation to its size that the calotte is malleable in the plane of the lower periphery. However, should the thickness should preferably be so large that the cap is rigid in the vertical joint. As an example, it can be mentioned that for a device intended to improve the anchorage of a fixture and having a diameter of about 7 mm at the lower periphery 2, the thickness is suitably about 0.1 mm.

The device is furthermore in the embodiment shown in Fig. 1. the mold provided with perforations 4. These perforations can occupy a larger or smaller part of the surface of the skullcap. -b> 0 \ CJO 10 15 20 25 30 35 CN \O 4 Fig. 2 shows the device 1 shown in Fig. 1 attached on a fixture 5, which is screwed into bone tissue 6, with help of a screw 7. the opening 3 advantageously has a smaller diameter f) than the cross-sectional area of the fixture 5 so that the device can rest towards the top of the fixture 5.

In the following, a way to anchor a fixture in a heavily resorbed jawbone is described.

It begins by exposing the area of the the jawbone to which the fixture is to be attached by lamb, ie the mucous membrane and the periosteum that normally cover the jawbone and which in Fig. 2 is denoted by 8, is dissected free from the leg and folded away. Then drill a hole in the jawbone and a fixture 5 are screwed into the bone so far its thickness allows.

If no further action was taken now would not the fixture after solidification withstand the stresses of a bridge which is attached to the fixture because it is not screwed into a sufficiently thick jawbone. Using the device according to the present invention, however, a growth of the bone tissue 6 is induced, which produces a peaceful anchoring. For this purpose, a different order 1 of the type shown in Fig. 1, the lower periphery of which 2 delimits an area that is significantly larger than the fixture 5 cross-sectional area. As an example can be mentioned that fixtures usually has a diameter of 3-4 mm and that the recommended center-to-center distance between fixtures is gw 8 mm. This means that the device 1 can at most have an output stretch of about 8 mm in the "jaw direction" if adjacent fixtures must be able to be fitted with a device according to the finding.

Then the device 1 is attached to the fixture 5 by means of * of a screw 7 which is screwed in in the internal thread 9 in the fixture 5. The device forms a cap over the fixture 5, * thereby creating a space 10 between the skull, the bone tissue 6 and the fixture 5. This area will immediately fill las with blood, which results from bleeding that occurs at 10 15 20 25 30 35 5 the exposure of the bone tissue and the drilling in the bone tissue.

When the cap 1 has been put in place, the lamb is placed over the order 1 and the fixture 5 and sewn into the surrounding fabric nad.

Over the course of a couple of months, the bone tissue comes 6 to grow into and grow into the space 10, thereby obtaining an improved anchoring of the fixture 5. When the space 10 has been completely filled with bone tissue, the lambda can be loosened again, the screw 7 is removed and a bridge is anchored in the fixture 5 and adjacent fixtures, which may also have been anchored by means of a device according to the invention. It thus anchored fixture 5, withstands the stresses from the bridge to due to the fact that it is completely anchored in the bone tissue 6.

The device 1 does not need to be removed after that bone growth has occurred. Since the device is manufactured made of tissue-compatible and inert material no problem to leave it in the jaw. If you still want to remove the device when the desired bone growth has achieved, this is also possible. If the device persists of osseointegrating material, however, it must be treated with any suitable substance so that none osseointegration occurs.

We currently believe that bone growth is promoted by creating the space 10 for the blood. In the blood, the the surrounding bone tissue and the periosteum are in fact forming cells that we believe form new bone tissue when the blood coagulates and breaks down. If the lamb is not kept away with with the help of the device 1, however, the lamb grows to and makes bone growth impossible.

The perforations serve to enable a fast revascularization of the blood clot in space 10. This is believed we are all the more important the larger the space 10 is, after- as the clot is dependent on oxygen and nutrient supply from surrounding tissue and it is not safe to oxygen and nutrient supply from only the adjacent bone tissue is sufficient. If then the device is provided with perforated $> Q \ CD LN (14 10 15 20 25 30 35 QD 6 rings 4, the oxygen and nutrient supply can be increased by newly formed vessels are given the opportunity to grow in through rings and into the blood clot. However, we do not believe that the linings are absolutely necessary. On the contrary, it could be an advantage of a continuous cap that prevents connective tissue ingrowth.

As previously mentioned, the device 1 is preferably moldable. This is an advantage if the jawbone in which the fixture 5 to be attached is so narrow that the periphery 2 of the device is outside the jawbone when the device is mounted on the or if the shape of the jawbone does not otherwise fit together with the device 1. The device 1 can then be easily shaped after the existing jawbone. However, the device, such as also mentioned, be rigid in the vertical joint. The reason for this is that we believe that it is essential that the blood clot in the space 10 is still to avoid connective tissue formation.

Many patients have to use a loose prosthesis during and if the device is not rigid in the vertical joint, the stresses from the loose prosthesis can cause that the clot moves and is disturbed.

Fig. 3 shows an example of a device according to the finning, which is used to regenerate through bone growth or create a cheekbone. In this case, the device includes an arched, malleable element of small thickness.

The element ll has rounded edges to avoid damage on surrounding tissue. As in the case of FIG l perforated to enable oxygen and nutrient supply to the blood clot in the outlet defined by the device space. The device comprises mounting means 12, which in this case consists of three pins, which are placed on the device periphery and attach to the bone tissue around the area in what growth of bone tissue is to be achieved.

The device is used in a corresponding manner that has written above. The area in which bone growth is desired to be laid by free dissection of the lamb. Then attach the scheme, which has first been formed into a form 10 15 20 25 30 35 468 359 7 matches the one desired for the created bone tissue, using the pins 12 in the existing bone tissue.

Then place the lambán in place over the device and sew fixed. After a couple of months, bone growth has been achieved in the space under the device.

Claims (5)

Üx CO (JJ (JJ 10 15 20 25 30 35 vD PATENTKRAV A device for promoting the growth of bone tissue in a human or animal, characterized in that it is arranged to be placed between the bone tissue whose growth is to be promoted and the lambna which normally covers the bone tissue, that it consists of tissue-compatible, inert material, and that it comprises a curved, perforated and vertically rigid element (11) of small thickness, the outside of which element is arranged to be in contact with the lambán and the inside of which is arranged to face the bone tissue to create a space between the element and the bone tissue, and mounting means (12) for attaching the element to the bone tissue. Device according to claim 1, n a d in that it consists of titanium. Device for providing an improved anchoring of an implant (5) in bone tissue (6), characterized in that it is substantially in the form of a perforated and vertically rigid cap (1) with a lower periphery (2), which delimits a surface which is considerably larger than the cross-sectional area of the implant (5), that it consists of tissue-compatible, inert material of small thickness and that it has means (3) which make it possible to mount it on the implant . k ä n n e t e c k - Device according to claim 3, n a d in that the material is titanium. Device according to claim 3 or 4, characterized in that it is malleable in the plane of the lower periphery. k ä n n e t e c k - 'fa