Enossal single tooth implant with twisting prevention

[21] Appl. No.: 701,688

[22] Filed: Aug. 22, 1996

[30] Foreign Application Priority Data

Sep. 20, 1995 [DE] Germany 195 34 979.2

[51] Int. CI.6 A61C 8/00

[52] U.S. CI 433/173

[58] Field of Search 433/172, 173,

433/174

[56] References Cited

U.S. PATENT DOCUMENTS 4,960,381 10/1990 Niznick .

5,000,686 3/1991 Lazzara et al 433/174

5,078,607 1/1992 Niznick 433/174

5,125,840 6/1992 Diirr et al. .

5,195,892 3/1993 Gersberg 433/174

5,199,873 4/1993 Schulte et al 433/174

5,449,291 9/1995 Lueschen et al 433/173

5,577,912 11/1996 Prins 433/173

5,620,323 4/1997 Bressman et al 433/174

FOREIGN PATENT DOCUMENTS

4022753 1/1992 Germany 433/174

41 27 839 3/1992 Germany .

4127436 3/1992 Germany 433/173

4238383 7/1994 Germany 433/174

413 224 12/1966 Switzerland .

9406367 3/1994 WIPO 433/173

9420043 9/1994 WIPO 433/173

Primary Examiner—Ralph A. Lewis Attorney, Agent, or Firm—Hill & Simpson

An enossal single tooth implant for a tightly fitting dental prosthesis comprises a substantially cylindrical base body insertable in a bore made in a jaw bone and having a blind bore extending inward from one end for receiving a plug portion of a spacing sleeve with the spacing sleeve and the blind bore having an arrangement of coacting elements to prevent a twisting therebetween. The coacting elements include at least one axially extending groove and at least one axially extending projection with each groove being located immediately adjacent the outer edge of the base body and with each projection being adjacent a shoulder of the spacing sleeve which shoulder is engaged on the outer edge of the base body when the sleeve is mounted thereon. In addition to the positive elements, the plug portion has a cylindrical guiding portion followed by a cylindrical centering portion of a smaller diameter. The blind bore of the basic body also has stepped portions of different diameters with the largest diameter being adjacent the open end and forming a guiding surface for the guiding portion of the sleeve and followed by a smaller diameter portion forming the centering portion.

19 Claims, 2 Drawing Sheets

1

ENOSSAL SINGLE TOOTH IMPLANT WITH
TWISTING PREVENTION

BACKGROUND OF THE INVENTION 5

The present invention is directed to an enossal single tooth implant for tightly fitting a dental prosthesis which implant includes a base body, that is insertable in a bore made in a jawbone and a spacing sleeve attachable to the base body. The base body has a blind bore open on one end 10 which is a coronal end and closed at the opposite end. The spacing sleeve is attachable in a twisting prevented manner to the coronal end of the base body and has a reduced diameter centering collar which is insertable into the hollow cylindrical annular recess formed by a blind bore in the base 15 body adjacent the coronal end while a shoulder of the sleeve is received on the outer edge of the body at the coronal end. The spacing sleeve has a bore that extends through the centering collar and is open on its coronal end for the reception of an implant post. The connection device for the 20 twist preventing connection of the spacing sleeve is formed with the hollow cylindrical annular recess of the basic body having at least one circumferentially acting basic body positive connection element and the centering collar of the spacing sleeve has at least one spacing sleeve positive 25 connecting element complimentary to the basic body positive connecting elements. The implant post will directly or indirectly be insertable into the blind bore of the base and at least partially traverse the spacing sleeve and the fastening head for the dental prosthesis. 30

In a single tooth implant of this type such as disclosed in U.S. Pat. No. 5,125,840, whose disclosure is incorporated by reference thereto and which claims priority for German application 4 028 885 and from German patent application 3J P 195 09 762.9-32, the twisting prevention was undertaken in that the basic body had a positive connecting elements which were provided on the bottom of an annular recess of the basic body and the spacing sleeve positively connecting elements which were complimentary thereto are on the 4Q lower front edge of the centering collar of the spacing sleeve. From a manufacturing standpoint such positive connection elements are relatively difficult to produce. In certain uses, the location of these positive connection elements was undesirable since the full depth of the annular recess or the ^ full length of the centering collar is not available for centering, fixing and securing of the spacing sleeve relative to the basic body.

In U.S. Pat. No. 4,960,381, other difficulties of a similar nature occur in the enossal dental implant. The difficulties 50 are due to the fact that the positive connection elements of the basic body are spaced from the coronal front edge within a blind bore of the basic body.

SUMMARY OF THE INVENTION

55

The object of the prevent invention is to develop a single tooth implant wherein the case of improved manufacturing possibilities and even precise guidance and centering of the spacing sleeve in the basic body is ensured.

To accomplish these objects, the present invention is 60 directed to a single tooth implant having a basic body, a spacing sleeve and means for preventing twisting therebetween. The basic body has a blind bore forming a coronal end for the body and has a positive connection area adjacent the coronal end followed by a guide portion with a cylin- 65 drical surface and then a centering area with a diameter smaller than the cylindrical surface of the guide portion. The

2

spacing sleeve has a fastening end spaced from a plug portion by an annular shoulder. The plug portion adjacent the shoulder has a positive connecting portion on a cylindrical portion followed by a guidance portion with a cylindrical surface and a centering portion with a cylindrical surface with a smaller diameter than the cylindrical surface of the guidance portion. The diameter of the cylindrical surface of the guidance portion matches the diameter of the guide portion of the blind bore while the diameter of the centering portion matches the diameter of the centering area of the blind bore. The means for preventing twisting includes positive connecting elements in the positive connecting portion and positive connecting area with the elements including at least one groove and at least one projection receivable in the groove when the plug portion is inserted into the blind bore with the annular shoulder engaging the end face of the coronal end.

The centering body of the basic body can be provided with internal threads. The invention optionally provides for the internal threads being cervically connected to the centering area of the basic body and the threads are disposed inward toward the closed end of the basic body.

Another embodiment of the invention is characterized in that the implant post completely traverses the spacing sleeve and can be screwed into internal threads close to a cervical or closed end of the basic body.

It is also possible according to the invention for at least one of the basic body positive connection elements to have the form of a coronally open positive connection groove extending parallel to the longitudinal axis of the basic body.

The invention also proposes that the positive connection grooves have in a radial plane, which extends perpendicular to the axis of the bore, a basic substantial circular segmental cross section. The positive connection grooves can have a substantially triangular cross section in a radial plane which extends perpendicular to the axis of the bore in the basic body. The invention optionally proposes that the positive connection grooves in a radial plane which extends perpendicular to the axis of the bore in the basic body has an approximately rectangular-curved cross section. According to the invention the positive connection grooves can be opened toward the closed or cervical end.

It is also possible according to the present invention for the positive connection grooves to have a decreasing cross section from adjacent the coronal end towards the closed end of the basic body. The invention also proposes the cross section of the positive connection grooves decreases radially from the coronal and to the closed end of the basic body. The basic body connection elements can have a 30° spacing with respect to the basic body circumference.

The invention also proposes that the basic body positive connection elements have a 60° spacing with respect to the basic body circumference.

According to the invention it is also possible for the number of positive connection elements of the spacing sleeve to be smaller than the number of positive connection elements of the basic body.

Another embodiment of the invention is characterized in that the positive connection area of the basic body has an annular undercut between the positive connection elements of the basic body and the guidance area.

It is also possible according to the present invention for the end wall at the coronal end of the basic body to have a bevel or chamfer tapering conically inward from the front edge of the basic body into the vicinity of the basic body positive connection elements.