GB2210792A - Dental posts - Google Patents

Abstract

A dental post in the form of a drill bit has a cutting shank 1 at one end and a part (3) for connection to the drill at the other end. A central enlargement 6 with peripheral cutting edges 8, and radially projecting prongs 10 are provided between the shank (1) and the drill connecting part 3. The shank 1 and central enlargement 6 are drilled into a tooth and the drill connecting part 3 is removed to leave the projecting prongs 10 which provide a secure attachment for a fabricated crown. <IMAGE>

Description

DENTAL POSTS This invention relates to a dental post for use in the attachment of an artificial crown to an existing tooth root.

Patent Specification No. 1,129,143 describes a dental post in the form of a drill bit having a frusto-conical head, a shank with a cutting edge projecting from the larger end of the head, and an extension piece projecting from the opposite end. In use, the extension piece is fitted into the chuck of a dental drill and a bore is cut in a tooth root with the cutting edge. The extension piece is then removed and the shank is cemented into the bore with the frusto-conical head engaging the top of the root. An artificial crown of appropriate shape is then cemented around the frusto-conical head.

With this known arrangement there is the problem of ensuring that the post is securely anchored in position in the tooth root and also of ensuring that the crown is securely fixed to the frusto-conical head.

An object of the present invention is to provide an improved dental post in the form of a drill bit with which secure location relative to the tooth root and the crown can be achieved in a particularly simple and convenient manner.

According to the invention therefore there is provided a dental post in the form of a drill bit having at one end a connecting structure for drivable connection to a drill, at the opposite end a shank with a cutting periphery thereto, a first central portion adjacent said shank having a cutting periphery thereto which projects radially beyond the cutting edge of the shank, and a second central portion adjacent said connecting structure having at least one element projecting radially outwardly therefrom.

With this arrangement the said first central portion can cut a relatively large recess in the tooth root on top of the narrower bore cut with the shank whereby both the shank and first centrl portion can be cemented within the root to provide secure anchorage relative thereto.

Also, the projecting element or elements facilitate secure attachment of a fabricated crown on the post.

With regard to the said connecting structure this may comprise an extension piece for engagement with a drill chuck, which piece is formed as an integral part of the drill bit. In this case the extension piece is cut off after the tooth root has been drilled. Alternatively the connecting structure may comprise a projecting plug member or a socket detachably cooperable with a corresponding configuration at the end of a separate extension piece for engagement with a drill chuck. In this case the arrangement may be such that it is only necessary to remove the extension piece after the tooth root has been drilled.

The cutting periphery on the shank may comprise one or more edges of spiral configuration, as also may be the cutting periphery on the first central portion. Preferably these cutting edges on the shank and the central portion merge continuously with each other. Possibly, cutting peripheries other than spiral edges such as straight edges or other constructions may be used.

The said projecting element or elements may comprise one or more spokes.

The invention will now be described further by way of example only and with reference to the accompanying drawings in which Figure 1 is a diagrammatic side view of one form of a dental post according to the invention; Figure 2 is a diagrammatic sectional view showing a tooth root fitted with a fabricated crown using the dental post of Figure 1; and Figures 3-and 4 are part views to a larger scale of modified versions of the dental post of Figure 1.

The dental post shown in Figure 1 is in the form of a one-piece rigid metal bit or reamer having a cutting portion 1 at one end which is of generally cylindrical form and is provided with three spiral cutting edges 2, and a connecting portion 3 at the other end in the form of a cylindrical extension piece 4 terminating in a shaped end part 5 adapted to fit within the chuck of a dental drill.

Adjacent the cutting portion 1 there is an enlarged central portion 6 of generally circular cross-section. As can be seen this central portion tapers from a central position 7 of maximum diameter so as to merge smoothly with the cutting portion 1. The central portion 6 also has three spiral cutting edges 8 and these merge continuously with the cutting edges 2 on the cutting portion 1.

The central portion 6 also tapers from the central position 7 so as to merge smoothly with a small diameter neck 9 which joins the central portion 6 with the extension piece 4. Prongs 10 project radially outwardly from the central portion 6 adjacent the neck 9 at equally circumferentially spaced positions. There may be any suitable number of prongs, say four or more.

In use the bit is used to drill a hole in a tooth stump to a depth generally equal to the distance between the tip 11 of the cutting portion 1 and the central position 7. The bit is then removed, the bore is cleaned out, the connecting portion 3 is removed by cutting through the neck 9, and the remaining part of the post is fixed in position in the bore using a suitable dental cement. The post fits snugly in the bore with the top of the central portion 6 and the prongs 10 projecting above the top surface of the tooth stump 12. A suitably shaped artificial crown 13 is connected in position on top of the stump 12, such crown 13 being formed with a central aperture or slots or the like to receive the prongs 10.

With this arrangement it will be appreciated that the post fits in a particularly secure manner in the tooth stump 12 due to the action of the enlarged central portion 6, and the crown is particularly securely retained due to the action of the prongs 10. Moreover, it will be understood that fitting of the post and crown can be achieved in a particularly simple, quick and convenient manner having regard to the assistance afforded in this respect by the shape and construction of the post .

As shown in Figures 3 and 4, the bit can be formed in two or more parts with a square section plug 14 and socket 15 arrangement or the like for releasably interconnecting the extension piece 4 with the remainder of the post. In this way, the extension piece 4 can be removed after drilling of the bore without requiring cutting of an interconnecting neck. With the arrangement of Figure 3 no cutting operation at all is required. With the arrangement of Figure 4 it may be necessary or desirable to trim off the projecting plug 14 before fitting the crown.

It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiment which are described by way of example only.

Claims (5)

1. A dental post in the form of a drill bit having at one end a connecting structure for drivable connection to a drill, at the opposite end a shank with a cutting periphery thereto, a first central portion adjacent said shank having a cutting periphery thereto which projects radially beyond the cutting edge of the shank, and a second central portion adjacent said connecting structure having at least one element projecting radially outwardly therefrom.

2. A dental post according to claim 1, wherein said connecting structure comprises an extension piece for engagement with a drill chuck, which piece is formed as an integral part of the drill bit.

3. A dental post according to claim 1, wherein said connecting structure is detachably co-operable with a corresponding configuration at the end of a separate extension piece for engagement with a drill chuck.

4. A dental post according to claim 3, wherein said connecting structure comprises a projecting plug member.

5. 10. A dental post substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.

5. A dental post according to claim 3, wherein said connecting structure comprises a socket.

6. A dental post according to any one of claims 1 to 5, wherein said shank has a cutting periphery comprising one or more edges of spiral configuration.

7. A dental post according to any one of claims 1 to 6, wherein the cutting periphery on said first central portion comprises one or more edges of spiral configuration.

8. A dental post according to claims 6 and 7, wherein the cutting edges on the shank and the first central portion merge continuously with each other.

9. A dental according to any one of claims 1 to 8, wherein the said projecting element or elements comprise one or more spokes.