WO1991000711A1

WO1991000711A1 - Arrangement for support of a denture and method for insertion of the same

Info

Publication number: WO1991000711A1
Application number: PCT/SE1989/000401
Authority: WO
Inventors: Nils Berglind
Original assignee: Nils Berglind
Priority date: 1988-01-13
Filing date: 1989-07-10
Publication date: 1991-01-24
Also published as: SE460333B; SE460333C; SE8800082D0; SE8800082L

Abstract

The invention relates to a device for support of a denture comprising sleeves (1), columns (2) and a bridge construction (3). The upper part of the columns (2) is cone-shaped, and the bridge construction (3) is divided in separate parts each comprising a sleeve (5) with an inner cone-shaped portion. The sleeve (5) is provided with two wing-formed extensions (6) whereby the bridge parts are attached on a respective cone-shaped column (2) and the wing-formed extensions (6) are overlappingly connected to each other to form a continuous bridge (3) attached to the columns (2), which in turn are arranged in the implant sleeves by fixing screws (7). The bridge construction (3) is attached without looseness, and its parts (3, 8) are connected to each other following the attachment in a way that allows for compensation of obliqueness of the implant sleeves and a great individual adaptability.

Description

ARRANGEMENT FOR SUPPORT OF A DENTURE AND METHOD FOR INSERTION OF THE SAME

The present invention relates to an implant construction of e.g. titanium for support of a denture, comprising inwardly and outwardly threaded implant sleeves intended to be screwed directly into the jaw-bone, inwardly and outwardly threaded columns intended to be screwed into the implant sleeves and a bridge construction which is to be attached on the columns screwed into the implant sleeves. The invention also relates to a method of producing such an implant construction.

People needing dentures are, for example, those suffering from loosening of the teeth and those who have had traffic accidents and injured their teeth and jaw-bones. Loosening of the teeth is most often caused by periodontitis , i.e. an inflammation in the tissues surrounding the teeth and constituting their attachment to the jaw-bone. The main cause is infection but also inapproporiate bite-relationship between the upper and lower jaws, certain diseases (e.g. diabetes), hormonal changes and smoking can effect loosening of the teeth. Most often loosening of the teeth begins with periodontitis, which comes insidiously and is not painful, and in many cases the patient does not notice anything until the teeth begin to get loose and fall out. In those cases where the patient has not been able to prevent this with improved mouth hygiene, changed eating habits etc., whole or partial dentures are employed. Dentures available today for the whole upper or lower jaw are either permanent dentures or so called dental plates. Dental plates are often experienced as a psychiological inhibition since they often fit loosely and the patient has difficulties in eating ordinary food. Recently, implanted dentures with a core of titanium have become more and more common due to the discovery that the human body does not perceive unalloyed titanium as foreign.

Prior art dentures are supported by a bridge attached on implanted screws of titanium. The screws consist of a sleeve part to be screwed directly into the jaw-bone, and a column part to be s crewed into the s leeve part. The bridge part is constructed by taking an impress ion of the jaw with the temporary cover s crews instead of the columns in the s leeve parts and then us ing this as a mould . Thereafter a plate of , e. g. , titanium or gold is moulded in the bottom thereof in such a way that holes are obtained fitting over the protruding pa rt s of the i mp lant s . The p l at e , or b r idge part , i s thereafter provided with artificial teeth and attached to the implants in the mouth of the patient by fixing screws.

A disadvantage of this known technique is that the implant holes into which the implant s leeves are s crewed, mus t be drilled absolutely paral le l to ensure tight fitting of the denture. I f the holes are expanded to fit over all the parts o f the implants protruding out of the jaw-bone, the denture will fit loosely. I f on the other hand the holes are not expanded and the bridge part is pres s ed over all protruding implants, the patient will experience uncomfortable tensions in the jaw-bone. To avoid these disadvantages the bridge part moulded in one piece has been divided into two or more pieces .

Another disadvantage of the prior art is that the loos e f itting of the dentures provides undesired spaces in which contaminating bacteria can be enclosed.

Therefore, the object of the present invention was to create a new implant construction for support of a denture in which the bridge part provided with artificial teeth can be attached in a tight fitting and tensionfree way independently of whether the holes for the implant s leeves are drilled absolutely parallel or not.

The invention achieves this object in that the lower part of the columns is outwardly threaded to be s crewed into the implant sleeves and has a cone-shaped part fitting into the cone-shaped recess of the implant sleeve. The upper portion of the columns which after being screwed into the sleeves pro- trudes out of the implant sleeves is also cone-shaped. The bridge construction is divided in separate parts each comprising a sleeve with an inwardly extended cone-shaped portion fitting onto the upper cones of the columns. The cone- shaped portion extends along approximately half the length of the sleeve and at the tapered portion it defines a shoulder for a fixing screw to be screwed into the inwardly threaded holes of the columns from above and below, respectively. The bridge construction also comprises two wing-formed extensions on each side of the sleeve. The bridge parts are each attached onto a cone-shaped column and the wing-formed extensions are joined together in an overlapping relationship to form a continuous bridge attached to the columns, which in turn are threaded in the implant sleeves, by fixing screws.

The invention will be described in more detail below and with reference to the accompanying drawings, in which

Fig. 1 is a schematic view of the implant construction accor¬ ding to the present invention,

Fig. 2 is a plane view of the implant construction,

Fig. 3 is a schematic exploded view of the separate parts of the implant construction,

Figs. 4-5 show the implant construction assembled on its place in the jaw-bone in front view and plane view, respectively, and

Fig. 6 shows, for illustrative purposes, the connection of the parts of the bridge construction in case of inclined implant sleeves.

The implant construction shown in Fig. 1 is preferably made of titanium. The implant construction comprises implant sleeves 1, columns 2, a bridge construction 3 and fixing screws 7. The implant sleeves 1 are provided with an outer thread and are screwed directly into the jaw-bone. The implant sleeves are also provided with an inner thread and a cone-shaped recess. In the cone-shaped recess there is an instamped hexagonal key grip employed by the dentist when screwing the sleeve into the jaw-bone. This is a very important feature of a preferred embodiment of the present invention since the healing into the jaw-bone improves considerably if the outside of the implant sleeve has a finish which is as smooth as possible. Columns 2 are screwed into the implant sleeves 1 and provided with an outer thread and a lower cone-shaped part fitting to the implant sleeves^' 1. The cone-shaped parts are relatively long which prevents loose fitting and optimizes load transfer and tightness between the details. The columns 2 are also provided with another upper cone-shaped part simplifying the attachment of the bridge construction 3. Furthermore, the columns 2 are provided with an inner thread for securing the bridge construction 3 by fixing screws 7. The bridge construction 3 consists of separate parts which are connected to each other in an overlapping way.

An embodiment of the construction of the bridge parts and their connection with each other is shown in Fig. 2. The individual parts mainly consist of a sleeve 5 and two wing- formed extensions 6. The short sides of the extensions are arranged on each side of the centre axis of the sleeve 5 which is important for the assembly of the bridge. To form a continuous bridge the wing-formed extensions 6 are attached in an overlapping way to each other by screws, rivets or spot welding. In case the implant sleeves have been screwed into the jaw too far away from each other a connection piece 8 is employed. The design of the connection piece 8 corresponds to the design of the bridge parts with the exception that the central portion, i.e. the sleeve 5, has been removed.

In Fig. 3 a schematic exploded view of the separate parts of the implant construction is shown. The upper cone-shaped part of the column 2 prevents loose fitting of the sleeves 5 of the bridge parts, since the latter are provided with corresponding cone-shaped recess es . The wing- formed extensions 6 o f the bridge part are overlappingly attached to each other after the sleeves 5 have been placed in correct position. Thereafter the teeth-provided bridge construction 3 is locked to the columns 2 with fixing screws 7 , the heads of which rest against a shoulder 4 formed by the tapering portion of the cone-shaped recess of the sleeve 5.

There are shown in Fig. 4 a front view and in Fig. 5 a plane view of the implant construction as sembled in p lace in the j aw-bone of a patient . The separate bridge parts 3 and the connection pieces 8 are individually bent according to the jaw contour of the patient. In Fig. 4 the bridge construction is as s embled by spot welding and in Fig. 5 by s crew s 9. In certain cases screwing is preferred since this increases the retention of the denture.

In the following the insertion of the implant according to the present invention will be described. After removing the tissue from the jaw-bone the dentist drills a desired number of holes therein. For a complete denture for the low er or upper j aw approximately six hole s are needed. Of cours e , it is al so pos s ible to us e shorter bridge parts. During the dri lling abundant amounts of irrigating fluid is provided preventing too high of a temperature and eliminating necros is . After threading with a pilot tap the implant sleeves 1 are screwed into the jaw-bone which is accomplished in that a special tool is ins erted in the instamped hexagonal key grip. Thanks to this inner stamping the outside of the implant s leeves 1 can have a smooth finish which improves the healing of the implant into the jaw-bone. Thereafter temporary cover s crews are screwed into the implant sleeves 1 and the mucous membrane is replaced and sutured. After a neaiing time of approximately 3- 6 months the dentist punches a hole over each implant sleeve and the healing s crews are replaced with the columns 2. Thereafter an impres s ion of the jaw with inserted implant sleeves 1 and columns 2 is made, whereby temporary, not shown, matrix s crews are screwed into the columns 2 to cover the threaded holes in the columns during the time the impression is taken. Thereafter, this impression is employed to make a mode l to which the bridge construction 3 is adapted after mounting.

If the dentist has not drilled the holes completely parallel which for many reasons can be very difficult, this can be compensated for at the assembly of the separate parts of the bridge construction 3 to each other, which is shown schematic¬ ally in Fig. 6. First the separate bridge parts are assembled on a respective column (i. e. on a model ) and thereafter the wing-formed extensions 6 of the bridge parts are connected to each other in an overlapping way. On account of this , the implant sleeves do not have to be absolutely parallel threaded into the jaw-bone. If an implant sleeve 1 should be drilled so obl iquely in the jaw-bone that the tip of the upper cone of the column 2 gets outs ide the vertical line, the bridge con¬ s truction can be as sembled in two or more parts and screwed together in the mouth of a patient. As mentioned earlier, the bridge parts are connected in an overlapping way. The connec¬ tion can occur, for example, by drilling and subsequent threading and rigid screwing, or drilling and riveting only, whereby the overlapping wing- f ormed parts 6 are drilled together two and two. The connection can also be done by spot welding. If the distance between two implant screws 1 should be too far to be connected by two wing- formed extensions 6 , a conne ction pi ece 8 can be emp loyed. In that cas e the connection piece is attached in the same way as the bridge parts and its design is the same as that of the bridge parts except for the central portion. Thereafter the bridge is provided with artificial teeth and is securely locked in the inwardly threaded holes of the columns 2 by fixing screws 7. The fixing screws 7 are covered with a filling of e.g. Akrylat which also has a locking function.

Thanks to the implant construction according to the pres ent invention having the exactly adjusted cone-shaped angles and the divided bridge construction, insertion of dentures is enabled without loose fitting. The earlier requirement to dril l the holes for implant s leeves absolutely parallel no longer exists. Due to the fact that the bridge construction cons ists of separate parts the individual pos sibilities for adjustment are within a wider range than before. Furthermore , with the construction according to the invention, the risk of tensions between the screws in the jaw-bone of the patient is decreased. Moreover, a denture according to the present inven¬ tion is eas ily kept clean because it consists of a minimal number of details. The cone-shaped embodiments provide for an absolute tightness between the implant sleeves and the columns and also between the columns and the bridge construction and thereby the enclosure of contaminations and bacteria in the construction is eliminated.

Claims

1. Arrangement for support of a denture, comprising inwardly and outwardly threaded implant sleeves (1) intended to be screwed directly into the jaw-bone, inwardly and outwardly threaded columns (2) intended to be screwed into the implant sleeves (1), and a bridge construction (3) to be secured on the columns (2), characterized in that the portion adjacent the outer thread of the columns (2) is cone-shaped to fit into a corresponding cone-shaped recess in the implant sleeves (1), in that the upper part of the columns (2), which protrudes after being screwed into the implant sleeves, is cone-shaped, and in that the bridge construction (3) is divided in separate parts each comprising a sleeve (5) with an inner cone-shaped portion sealingly fitting over the upper part of the columns, which cone-shaped portion extends along approximately half the longitudinal length of the sleeve and which at the tapering portion forms a shoulder (4) for a fixing screw (7), which is screwed into the jaw-bone from above or below into the inwardly threaded holes of the columns (2), and two wing- formed extensions (6) on each side of the sleeves (5), whereby the bridge parts being attached on a respective cone-shaped column (2) and the wing-formed extensions (6) are overlappingly connected to each other to form a continuous bridge (3) attached to the columns (2), which in turn are arranged in the implant sleeves, by the fixing screws (7).

2. Device according to claim 1, characterized in that the wing-formed extensions (6) of the bridge parts are connected to each other by screws (9).

3. Device according to claim 1, characterized in that the wing- formed extensions (6) of the bridge parts are connected to each other by rivets .

4. Device according to claim 1, characterized in that the bridge parts (3) are connected to each other by spot welding.

5. Device according to anyone of the preceding claims, characterized in that the wing-formed extensions (6) are arranged on a respective side of the centre axis of the sleeve (5).

6. Device according to anyone of the preceding claims, characterized in that the implant sleeves (1) are provided with an instamped hexagonal key grip, which is used during screwing into the jaw-bone, in the inner cone-shaped portion.

7. Device according to anyone of the preceding claims, characterized in that in case the implant sleeves (1) have been screwed into the jaw-bone too far away from each other a connection piece (8) is employed, the design of which corresponds to the design of the separate parts of the bridge construction (3) except for the central sleeve (5).

8. Device according to anyone of the preceding claims, characterized in that the implant sleeves (1), columns (2) and bridge construction (3) are made of titanium.

9. Method for insertion of an arrangement means for support of a denture, comprising threading of approximately six outwardly and inwardly threaded implant sleeves (1) directly into pre-drilled holes in the jaw-bone, screwing outwardly and inward-ly threaded columns (2) into the implant sleeves (1), attach-ment of a bridge construction (3) provided with artificial teeth on the columns (2) by screwing fixing screws (7) into the inner threads of the columns (2), characterized in that the bridge construction (3) consists of approximately six sleeves (5) with wing-formed extensions (6) on each side of the centre axis of the sleeve (5), the cone-shaped recesses in the sleeves (5) being sealingly attached, on a model of the jaw-bone with implant sleeves (1) and columns (2), on the cone-shaped parts of the columns (2) adapted to the cone- shaped recesses of the sleeves (5), in that the wing-formed extensions (6) of the bridge parts thereafter are overlappingly connected to each other, in that the thus formed bridge construction (3) is provided with artificial teeth and removed from the model and placed in a patient's mouth, in that the cone-shaped recesses in the sleeves (5) are placed over the cone-shaped portions of the columns (2) protruding out of the jaw-bone, in that the bridge construction is attached by screwing with fixing screws (7) into the inner threads of the columns (2), and in that the fixing screws (7) are covered with Akrylat which also has a locking function.

10. Method according to claim 9, characterized in that the wing-formed extensions (6) of the bridge parts are connected by drilling them together two and two and subsequent rigid screwing with screws (9).

11. Method according to claim 9, characterized in that the wing-formed extensions (6) of the bridge parts are connected two and two by riveting.

12. Method according to claim 9, characterized in that the wing-formed extensions (6) of the bridge parts are connected two and two by spot welding.

13. Method according to one or more of claims 9-12, characterized in that the wing-formed extensions (6) are attached to each other in an overlapping way, in that they are arranged on each side of the centre axis of the sleeve (5).

14. Method according to one or more of claims 9-13, characterized in that connection pieces (8) having a design corresponding to the bridge parts except for the central portion, are employed if the wing-formed extensions (6) are positioned too far away from each other.

15. Method according to one or more of claims 9-14, characterized in that all the parts in the device supporting a denture are made of unalloyed titanium.