Method and apparatus for shaping a site for anchoring an implant and to provide bone augementation and shape conformity

[0002] The present invention relates to method and apparatus for preparing a socket and more particularly to providing a method and apparatus which forms a socket of substantially uniform size and shape preparatory to receiving an implant which may be augmentable bone or a transplant.

[0003] There are a number of situations requiring implantation of a prosthesis. As one particular example, when it becomes necessary to remove a diseased tooth, it is typically replaced with a prosthesis. For the last fifteen years implantologists have been resigned to adapting to an oral cavity from which the diseased tooth has been removed. The existing situation has led to a non-consistent predictability as to such implantations which result from the following five factors:

[0004] 1. the competency of the doctor (implantologist or prosthodontist);

[0005] 2. the availability of bone and the proper configuration thereof;

[0006] 3. the patient's immunological system and habits that may contribute to accelerated breakdown;

[0007] 4. the compliance of the patient including the immune system function which will be handled holistically.

[0008] 5. non-predictable bone augmentation procedures.

[0009] The method and apparatus of the present invention serves to assure significantly more consistent predictability by providing a tool, for orthopedic use, which enhances and augments deficient bone in any surgical recipient site and thereby provide ideal standards having uniform predictability which provide implantologists and all prosthodontists using the tool to provide excellent results even in compromised situations having versatile parameters, which create optimum solutions and eliminate mediocrity.

[0010] The tool of the present invention and its method of use provides a fully integrated, stable, aesthetic biocompatible, structurally functional device which is perfectly adaptable to each individual, is simplified in its operation and which provides significantly enhanced predictable results of augmenting and implanting. The tool is comprised of an elongated cylindrical member having a hemispheric tip. The tip and side walls are expandable by rotating power or air pressure and are controlled for expansion by an air operated pump chamber for introducing air under pressure into the tool or by a lead screw.

[0011] The region between the tip and cylindrical, expandable side walls is provided with a plurality of grip extenders which are selectively projectable in an outward radial direction to anchor the tool preparatory to the expansion operation. The tool is placed into the cavity at the extraction site or surgical site and is expanded and contracted in a repeated fashion, compressing the side walls and base of the cavity providing a socket of more uniform dimensions and a site more densely enriched with bone and blood supply and cells to give the best bond and integration. The tool is then deflated and removed from the socket which is then scanned by a scanning device for determining the shape and volume of the socket in order to establish the amount and shape of augmented bone or transplant required for optimum intimacy and retention. The augmented boned is then shaped and placed into the cavity. The anchoring member of the implant is then inserted into the augmented bone.

[0012] It is therefore one object of the present invention to provide a novel method and apparatus for preparing a site within a bone for receipt of transplant synthetic or autogenesis or implant.

[0013] Another object of the present invention is to provide a novel tool for preparing a site for an implant having the capability of compressing bone within the cavity of the site to provide a more uniform socket for receipt of an implant which significantly enhances the precision placement of the implant or existing size or a scan and cut of a prosthetic component to fit on site.

[0014] The above as well as other objects of the present invention will become apparent when reading the accompanying description and drawings in which:

[0015] FIG. 1 shows an external side view of the tool embodying the principles of the present invention;

[0016] FIG. 2ashows a cross-sectional view of the tool of FIG. 1, looking in the direction of arrows 2a—2ain FIG. 1;

[0017] FIGS. 2b-2fshow more detailed views of members employed in the separating assembly shown in FIG. 2a.

[0018] FIG. 3 is a top view of the tool of FIG. 1, looking in the direction of arrows 3—3 in FIG. 1;

[0019] FIGS. 4a-4fshow the procedural steps employing the novel tool of the present invention;

[0020] FIGS. 5a-5cshow the procedural steps for a more conservative modification.

[0021] Making reference to FIGS. 1-3, there is shown therein a tool 10 designed in accordance with the principles of the present invention and comprised of a base member 12 having a centrally located, cylindrically-shaped pump chamber 12ain which a piston 14 is reciprocally mounted. A piston rod 14ais integrally joined to piston 14 and extends the length of the tool and into tip portion 16. Air under pressure is introduced from a source (not shown) through tubular member T and a bore 12b, causing piston rod 14, which extends upwardly and into the tip 16, to be lifted upon the introduction of air pressure into the lower end of chamber 12a, in the manner shown in FIG. 4d. Four (4) grip extenders 18 (see FIG. 3), provided at 90 degree intervals immediately beneath the tip 16, are extended outwardly under the control of a hollow cylinder 18a, rotatable about its longitudinal axis (see FIGS. 2aand 3). Linkage arms 18bare pivotally mounted to pivot 18eon projections 18cprovided on cylinder 18a. Each arm 18cis pivotally mounted at its opposite end to an extender 18 by a pivot pin 18d. The extenders are each either slidably mounted between a pair of guides 19 provided on a fixed upper plate 21 or guided by pins P mounted upon plate 21 and slidable within slots 18g. The upper plate also has a pair of integral stops 21a, 21bprovided thereon.

[0022] In operation, when cylinder 18ais rotated clockwise, arms 18bpull their extenders 18 inwardly, further movement being stopped by stop 21a. When cylinder 18ais rotated counter-clockwise, each pivot 18emoves over dead-center and movement stops by stop 21b, causing the extenders to move outwardly and “bite” into the cavity near the base thereof (see FIG. 4c) By moving slightly past over-center, the extenders are held in this position.

[0023] The cylinder 18ais rotated by means of a manually rotatable lever member 18flocated above a lower fixed plate 23. The arcuate outer periphery of member 18fis preferably knurled to facilitate gripping and rotation thereof, whereby extenders 18 become anchored into the side walls of the cavity.

[0024] Lower anchor plate 23 is joined to the lower end 24aof a fixed, hollow cylinder 24. The upper end 24bof cylinder 24 is fixedly secured to upper mounting plate 21. Piston rod 14aextends through anchor plate 23, outer cylinder 24, inner cylinder 18a, a central opening in knurled lever member 18fand a central opening in upper mounting plate 21. The upper end of piston rod 14ais joined to dome-shaped tip 16 for reciprocating the tip upon application of air pressure. The piston rod may be spring-loaded to return the dome 16 to the collapsed position or may be reciprocated by alternately applying pressure on opposite sides of the piston 14. Alternatively, the piston chamber may be replaced with an electromagnet, preferably operated by an a.c. source (not shown) operating upon the rod 14a(in a reciprocating manner) coupled to a plunger of the electromagnet. If desired a rotatable lead screw may be employed to selectively raise and lower tip 16.

[0025] The sidewalls 25 arranged between lower anchor plate 23 and upper plate 21 are each provided with upper and lower arcuate recesses 25a, 25b(see FIG. 2e). Resilient coil springs 27, 29 are respectively seated in the upper and lower slots 25a, 25bin the sidewalls 25, normally urging the sidewalls inwardly. The open ends of the recesses are sealed with a suitable material, such as an epoxy E, which does not interfere with the expansion and contraction of the springs 27, 29 while providing a substantially smooth outer surface.

[0026] A source of rotating power, or orthopedic surgeon's drill as a source for powering a dental drill, is coupled through a flexible, rotatable cable 31 to a coupling 32 arranged to extend from the undersurface of lower plate 23. Coupling 32 is joined to the lower end 33aof a shaft 33 which extends upwardly and clear of the small-diameter portion 18f-1 of the knurled lever member 18f, enabling clockwise and counterclockwise rotation of member 18fthrough a fixed angle (controlled by stops 21a, 21b) without interfering with the rotation of shaft 33 and vice versa.

[0027] The upper end 33bof shaft 33 is joined to a small diameter gear 34 which meshes with a larger diameter gear 35. Gear 35 has a central opening of a diameter sufficient to provide clearance for cylinder 24. Cylinder 24 has a pair of upper and lower bosses 24e, 24ffor positioning gear 35 therealong. A similar pair of bosses 24f, 24gretain the knurled lever member at a fixed position along cylinder 24. The knurled lever member 18fand gear 35 are preferably provided mounted upon cylinder 24 by suitable bearings arranged between the cylinder 24 and each of the members 18f, 35.

[0028] An annular member 35ahas its lower end 35bintegrally joined to the upper surface of gear 35. The outer periphery has a corrugated or fluted surface contour comprised of alternatively convex and concave shaped surfaces, which engage a similar shaped surface provided on each of the interior surfaces 25aof each of the sidewall sections 25. As the gear 35 is rotated (driven by members 31, 32, 33 and 34), the sidewall sections are reciprocated outwardly and inwardly thereby impacting upon the sidewalls of the cavity into which tool 10 is inserted, to thereby enlarge the cavity and make its sidewalls more uniform as to conform to the shapes of the reciprocating sidewalls (see FIGS. 4a-4c). Roller bearings may be provided between the engaging surfaces of the members 35aand 25.

[0029] A plurality of radially aligned guide plates 37 (see FIGS. 2aand 2d) have their upper and lower ends respectively secured to the underside of plate 21 and the upper surface of a plate 38 forming a cage-like structure. Each adjacent pair of guides limits the movement of elements 25 to inward and outward movement in the radial direction. The elements 25 may each be provided with a pair of guide pins 25crespectively at the upper and lower surfaces thereof, which are guided within cooperating radially aligned slots (or grooves) 21dand 38arespectively provided in plates 21 and 38.

[0030] The knurled lever member 18fis further provided with a plurality of arcuate-shaped openings, 18h, 18i18jand 18k(see FIGS. 2band 2c). Cylinder 24 is provided with cooperating cutaway portions, such as 24i, 24j, 24k, 24l(see FIG. 2b), leaving strut-like portions, such as 24g, 24h. The strut-like portions each extend through an associated one of the arcuate cut-outs 18h, 18i, 18j, 18k, enabling the member 18fto be selectively rotated without interfering with the cylinder 24, for selectively moving extenders 18 in and out under control of member 28 and cylinder 18a.

[0031] FIG. 1, showing a side view of tool 10, shows typical dimensional relationships for tool 10 when utilized for performing dental implants, it being understood that the present invention may be utilized for other bone implants or other bone augmentation in other parts of the body.

[0032] FIGS. 4a-4fshow various stages of the implant procedure. FIG. 4ashow a diseased periodontal support system requiring corrective action. The tooth T, shown in FIG. 4a, is extracted, leaving an extraction site creating an abnormal defect, as shown in FIG. 4b. It can be seen that the cavity resulting from the extraction has an irregular shape, making it extremely difficult to provide proper and precise alignment for a prosthesis.

[0033] In FIG. 4c, tool 10 is placed into the defective extraction site. The grip members 18 are extended, anchoring the tool within the cavity and near the base thereof. The tip portion 16 is urged upwardly and the sidewalls 25 are urged outwardly to modify all dimensions of the defective extraction site (i.e. length, width, depth, etc.) to facilitate precision placement of augmented bone or implant. FIG. 4dshows the manner in which tip 16 and sidewalls 25 are expanded. The result of this expansion causes the engaging side walls of the cavity to compress, resulting in a significantly more uniform socket, as shown in FIG. 4e. A comparison of the resulting socket, show in FIG. 4e, with the original defective area, shown in FIG. 4c, clearly indicates the enhanced uniformity of shape of the socket S. The tool 10 is preferably turned off and rotated about its longitudinal axis one or more times to assure that the walls of the cavity are uniformly compressed.

[0034] The socket may then be scanned by any suitable scanning device, such as the CEREC 1.11 and CEREC 2, manufactured by Sirona Dental Systems of Bensheim, Germany, or an other device having similar capabilities, in order to prepare augmented bone or implant and create optimum intimacy and retention. The compression of the side walls further enhances their strength and receptiveness to augmented bone and the intimate adhesion therewith, by creating a dense, enriched bed site.

[0035] The amount of augmented bone determined by the scanning operation is then introduced into the cavity.

[0036] Thereafter, as shown in FIG. 4f, the implant I comprised of a prosthetic tooth T′ and an anchoring portion A, is placed into the augmented bone. A hole is drilled in the augmented bone after its insertion and the implant is either threaded or tapped into the opening. The shape of socket S, shown in FIG. 4eand 4f, facilitates the capability of precision placement and alignment of the prosthesis T′ within the socket and relative to adjacent teeth, for example, alignment of the drilling or pre-drilled or pre-made hole in the bone.

[0037] FIGS. 5a-5cshow the process of the present invention in a case where the extract site requires less severe modification.

[0038] After extraction of the tooth, tool 10 is placed into the defective extraction site, the tool is operated to lift tip portion 16 and embed the grip extenders into the adjacent bone near the base of the cavity resulting from the extraction. The expansion cylinders 22 and 24 are expanded by the introduction of air under pressure, as shown in FIG. 5a, compressing the surrounding walls. The tool is then removed, leaving a socket S, as shown in FIG. 5b, in which the bone engaged by tool 10 is compressed to a desired length and diameter. Comparing FIG. 5bwith FIG. 4e, can be seen at the modification in FIG. 5bis much more conservative in nature.

[0039] The implant I having an anchoring portion A and a prosthesis portion T′ can be seen to closely match the size and shape of the extraction site as a result of the compression of the surrounding bone by the novel tool of the present invention.

[0040] Although FIG. 1 shows typical dimensions in applications for a tooth implant, it should be understood that the dimensions of the tool may be altered to be smaller or larger than those shown in FIG. 1, depending upon the particular application. In addition, it should be noted that the present invention is not limited to applications for performing tooth implants, but may be utilized for other oral, as well as non-oral implants, such as orthapedic prosthesis or surgical procedures, requiring precise dimensional modifications, and augmentation, for example.

[0041] A latitude of modification, change and substitution is intended in the foregoing disclosure, and in some instances, some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention described herein.