Drill

A drill is used on a jaw bone with overlying soft tissue and underlying, more solid bone. The drill comprises a first portion which is provided with one or more first cutting edges and with a first width or diameter. Arranged behind the first portion there is a second portion which is provided with one or more second cutting edges and with a second diameter exceeding the first width or diameter. The first portion can cooperate with soft tissues to form an initial hole, and the second portion can cooperate with the soft tissue and the more solid bone in order to enlarge said hole and create a countersunk hole in the more solid bone. The first portion is also depicted to cooperate with the more solid bone, during the second portion's formation of the countersunk hole, in order to provide a guidance hole or marker hole in the bottom of the countersink.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention also relates to a drill for use in dentistry and having said structure, and more particularly, to a drill which can be used on a jaw bone with overlying soft tissue and underlying, more solid bone.

2. Description of the Related Art

The drill is intended to be used in conjunction with the arrangement sold by Nobel Biocare AB Sweden under the name ARK (Absolute Rehabilitation Kit). Reference is made in purely general terms to the PCT applications WO 02/053055 A1, WO 02/053056 A1 and 02/053057 A1 filed by the same Applicant as for the present patent application. Reference is also made to what is generally already known in the technical field of drills.

Holes are formed in the jaw bones of patients in various circumstances and implantation situations. In cases where it is necessary to form a hole in the jaw bone, it is already known to mark out the drilling site initially and thereafter to expose the underlying jaw bone surgically and drill the hole using one or more first drills. Thereafter, a special countersinking drill is used to form a countersink intended for the head or outer part of an implant. Said drilling function has hitherto been performed using at least three different drills.

There is a need to be able to simplify and improve the hole formation function so that cutting-open of the soft tissue can be avoided and fewer drilling stages are needed, and so that the result of the hole formation is still satisfactory or can plainly be improved. It is a considerable advantage if the process of exposing the bone can be eliminated and the number of instruments and drills can be reduced without compromising the precision of the hole formation. It is also expedient if the same or similar instruments as used previously can also be used in the new context.

SUMMARY OF THE INVENTION

It is an object of the present invention is to solve at least some of the aforementioned problems. Accordingly, one aspect of the present invention comprises a drill that has a first portion designed to cooperate with the soft tissue to form an initial hole in the latter and a second portion that is designed to cooperate with the soft tissue and the more solid underlying bone for enlargement of said hole and for formation of a countersunk hole in the more solid bone. A further characteristic is that the first portion is also designed to cooperate with the more solid bone, during the second portion's formation of the countersunk hole, in order to produce a guidance hole and/or marker hole in the bottom of the countersink.

In other embodiments of the present invention, the number of first and second cutting edges can be two, three or four. The first portion can be plate-shaped and arranged in the longitudinal direction of the drill. The plate-shaped first portion can have a length of about 1.5 mm and is also designed with a tip through which the center line of the drill extends. The first portion has the first cutting edges arranged along its sides. The second cutting edges are inclined in order to form an inclined surface in the countersink. The inclination of the surface is arranged so that the surface narrows inward in a cone shape as seen in the hole formation direction. The second cutting edges can also be arranged with rectilinear parts for removing the material (gum) that arises during drilling. Further characteristics of the drill are set out in the attached dependent claims referring back to independent claim1.

Another embodiment of the present invention comprises a drill for use in dentistry with a first portion that is arranged at the front or distal end of the drill in order to form an initial hole, and in that a second portion that is designed to enlarge said hole and form a countersunk hole. The first portion is also designed in such a way that, during the second portion's formation of the countersunk hole, it produces a guidance hole and/or marker hole in the bottom of the countersink.

Another embodiment of the present invention includes a drill that comprises a first portion which is provided with one or more first cutting edges and with a first width or diameter, and, arranged behind the first portion, a second portion which is provided with one or more second cutting edges and with a second diameter exceeding the first width or diameter.

By what has been proposed above, the problems mentioned in the introduction are solved. With the new drill, the hole formation sequence can be changed around so that, for example, in contrast to previously known techniques, the countersunk hole is formed before the hole is drilled. In connection with the formation of the countersunk hole, the bottom of the countersink is marked out, which considerably facilitates application of the drill used for the continued hole formation in the jaw bone. This has the advantage of eliminating the need for separate marking and countersinking drills, these having now been combined in one unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

InFIG. 1, the drill as a whole is designated by1. The drill comprises an attachment by which the drill is connected to a drilling machine indicated only symbolically by reference number3. The drill also has a part4which bears the cutting edges in question. The part4comprises a first or front portion5and a second portion6. In the illustrative embodiment, the front portion5has the shape of a plate, and inFIG. 1the plate-shaped portion5is shown from the side, whileFIG. 2shows the first portion5in a view in which it has been turned 90° in relation toFIG. 5. The view according toFIG. 2shows that the plate-shaped portion5has a tip whose angle has been indicated by α. In the illustrative embodiment, the angle is chosen at about 120°. The tip is arranged so that the center line7of the drill extends through the tip. The plate-shaped portion2is further equipped with two first cutting edges, the first cutting edge having been designated by8and the second cutting edge having been designated by9. The first cutting edges8,9are thus arranged on both sides of the square-shaped part of the plate-shaped portion. The portion5can be given an alternative design, for example the number of first cutting edges8,9can be increased with further cutting edges, so that the total number of first cutting edges can be three, four, etc. It is also possible per se to use only one cutting edge although such an embodiment is not as advantageous. At its front parts, the second portion6is provided with cutting edges10,11which are inclined in relation to the center axis7. Said second cutting edges are situated to the side of the center line7and extend with angles β in relation to the center line which can be chosen at 45°. The second portion is also provided with a cylindrical surface25and recesses12via which material which arises during drilling in the jaw bone can be removed rearward and out to the side of the drill. The recesses are thus shaped with a rear curved wall13and first and second recess edges26,27. The number of second cutting edges can be varied and can, for example, be chosen as two, three, four, etc., cutting edges, such as including cutting edges10,11and28,29. The configuration with first and second cutting edges and first and second portions can also be seen from the end view according toFIG. 3where, inter alia, the portion5, the cutting edge8, the cuffing edges10and11, and the space12have been indicated. The first portion5is thus arranged at the front end of the drill, and the second portion6is arranged behind the first portion. The first portion can have a length L of about 1.5 mm. The second portion can have a length L′ of about 11 mm. The plate-shaped member can be arranged with a maximum width B, see view according toFIG. 2, of the order of 1.5 mm. The second portion can be designed with a diameter of about 4.7 mm. The plate-shaped portion can have a thickness of about 0.4 mm.

FIGS. 4 and 5show hole formation in a jaw bone14in two stages using the drill according toFIGS. 1,2and3. The jaw bone comprises a soft tissue part or gum15and, located under the soft tissue, a harder and more solid bone16, which can be cortical bone and/or trabecular bone.FIG. 4shows the first stage in which the partially shown drill1is arranged with the first portion5′ penetrating through the soft tissue5. During this penetration into and drilling of the soft tissue15, a hole17is formed which, inFIG. 4, is shown slightly enlarged, for the sake of clarity, in relation to the first portion5′. In the figure, the rotation about the center axis7′ of the drill is indicated by reference number18. The soft tissue15can be drilled without having to cut open the soft tissue part at the drill site, as was previously necessary. In the case shown inFIG. 5, the drill has penetrated deeper into the gum14. The hole17according toFIG. 4has been enlarged and the enlarged hole in the soft tissue15has been indicated by19. In this case too, the hole19has been shown enlarged in relation to the drill1′ for the sake of clarity. In addition to the enlargement of the hole17to give the hole19, the drill in the stage shown inFIG. 5has been moved down into the harder or more solid part of the jaw bone. This downward movement has meant that a countersunk hole20has been obtained in the more solid or harder bone16. The countersink is produced using the inclined second cutting edges10,11(cf.FIG. 2) on the second portion. The surface20in the countersink has the shape of a truncated cone and the cone angle of the surface corresponds to the one obtained with the inclined surfaces10,11. An inclined surface has been indicated by10′ inFIG. 5. In addition to the function of forming the countersink20, the drill has additionally produced a guidance hole and/or marker hole21at the bottom22of the countersink. The guidance hole and/or marker hole is produced with the aid of the first portion5′ and its first cutting edges which, upon rotation18of the drill, drive down into the harder or solid bone at the inner and middle parts of the countersink20so that the hole21is formed. When the countersink20and the hole21have been obtained, the drill can be withdrawn in the direction of arrow23. The direction of introduction of the drill is indicated by24inFIG. 4.

When the soft tissue15has been penetrated and the countersink20and the hole21are made, hole formation can continue using another drill (not shown in the figure) which can have a dimension corresponding to the bottom surface of the countersink. The countersink thus shaped like a truncated cone can be used for an implant (not shown) which, with its outer parts or its head, is applied in the countersink and, with its other parts, extends down into the jaw bone in the hole formed with said drill (not shown). It has been stated above that the countersink20has a surface shaped as a truncated cone. The countersink surface can of course have another shape, for example consisting of a cylindrical surface.

Although the foregoing systems and methods have been described in terms of certain preferred embodiments, other embodiments will be apparent to those of ordinary skill in the art from the disclosure herein. Additionally, other combinations, omissions, substitutions and modifications will be apparent to the skilled artisan in view of the disclosure herein. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the invention is not limited to the embodiment shown above by way of example, and instead it can be modified within the scope of the attached patent claims and the inventive concept.