US 3729825 A
An oral implant of the vented blade type is disclosed with a series of major improvements. The implant generally comprises a relatively thin vented blade portion adapted to be driven into a groove in the patient's jawbone, a crown supporting head and a neck portion connecting the crown supporting head to the blade portion.
Description (OCR text may contain errors)
United States Patent 1 Linkow et al.
[ ORAL IMPLANT  Inventors: Leonard I. Linkow, Cedarhurst; Charles M. Weiss; Lillian Bishop Weiss, both of New York, Abram Liwerant, East Meadow, all of N.Y.
 Assignee: Oratronics, Inc., New York, NY.
 Filed: Aug.2, 197] 211 App]. No.: 168,129
FOREIGN PATENTS OR APPLICATIONS 540,713 3/1956 Italy ..32/1O A Primary E.raminerRob ert Peshock A1mrneyMaxwell James et a1.
[ 51 May 1, 1973 5 7 ABSTRACT An oral implant of the vented blade type is disclosed with a series of major improvements. The implant generally comprises a relatively thin vented blade portion adapted to be driven into a groove in the patients jawbone, a crown supporting head and a neck portion connecting the crown supporting head to the blade portion.
The head is formed in the shape of a truncated pyramid and is provided at its underside with inclined beveled surfaces adapted to securely seat on chamfcred surfaces at the mouth of the groove in the ridge crest of the patients jawbone thereby to provide an automatic limitation on depth of insertion and tremendous increased lateral stability. The head portion is also provided with a plurality of accurately spaced score lines for facilitating measurement of depth of insertion.
The blade portion may take on a variety of contours designed to conform to various anatomical structures encountered and is preferably provided with a series of bone engaging teeth extending parallel to the sharp blade edge. Various blade contours and tooth profiles are disclosed including a preferred staggered tooth arrangement.
23 Claims, 27 Drawing Figures Patented May 1, 1973 3,729,825
3 Sheets-Sheet 1 INVENTORS. LEG/YARD 1. L/AAOW Pat ented May 1, 1973 3 Sheets-Sheet 2 FIG.
, INVENTORS. ZEOIYH/PD I z l/WfOW (#49155 M. WEISS ORAL IMPLANT The present invention relates to oral implantology and more particularly to improved designs of endosteal implants.
To replace lost teeth, dentists or oral surgeons in the past have utilized either a permanent or a removable bridge, depending upon the condition of the remaining teeth. If good natural teeth remain on both sides of the lost tooth or teeth, the adjacent natural teeth were ground down to form stubs for mounting a fixed bridge therebetween.
If, however, there were insufficient natural teeth remaining upon which to mount a fixed bridge, a removable bridge or denture is indicated. Such removable bridge structures include resilient clasps adapted to be latched onto the remaining tooth structure. A common and rather major difficulty encountered by patients having such removable bridges is that food particles tend to accumulate in the crevices between the bridge and the gum. This results in an unsanitary condition which breeds decay of the remaining natural teeth and may cause infection and injury to the gum. As a result, the bridge must be frequently removed for cleaning of both the bridge and the surrounding area.
Recently, dentists have become aware of the potential of oral implantology for providing a solution to the foregoing difficulties in the form of implant structures for permanently mounting an artificial tooth or teeth in the absence of sufficient natural tooth structure for constructing a conventional fixed bridge. As a result of this need for workable implant structures and techniques, oral implantology during the last decade has made great strides forward. Thus the field has developed from the now well knownsubperiostial implant techniques developed nearly twenty years ago to more recent advents of endosseous implants. These include the various pin type and spiral screw type implants which are inserted directly into the jawbone at the ridge crest and also the self-tapping vented implant designed by Dr. Leonard l. Linkow. The latest and most revolutionary endosseous type of implant is what is now known as the blade vent or ring type implant developed by Dr. Leonard l. Linkow and described in his U.S. Pat. No. 3,465,441 issued Sept. 9, 1969 and entitled Ring Type Implant for Artificial Teeth.
As described in that patent, this implant is designed with a thin razor sharp tapered implanting blade portion which is adapted to be embedded into the patients jawbone at the ridge crest. A relatively massive head portion extends up from the blade and serves as a sup port upon which the artificial tooth structure is mounted. The blade is preferably in the form of one or more complete or partial rings and is thus vcnted" substantially along its bone engaging side surfaces.
The insertion technique is rather simple and comprises incising the fibromucosal tissue at the ridge crest along the endendulous span involved, and reflecting that tissue away to expose the bone. The cortical layer at the alveolar crest is then grooved to a shallow depth and the blade is tapped to the desired depth into the bone. The tissue is then sutured.
The open vents in the blade allow for substantial regeneration of bone therethrough thereby providing greatly increased retention after healing and bone growth. When healing takes place after about a few weeks, the final impressions are taken to complete the final bridge.
While the vented blade implant is a revolutionary breakthrough in oral implantology, the technique and structures thus far designed pose several significant problems not the least of which is the great care and skill required by the dentist or oral surgeon using these implants. A primary drawback of these implants and one which has caused great hesitancy on the part of dentists to use them, is the possibility of serious injury to the various anatomical structures adjacent to the implant area such as sinous cavities, nerves, alveolar canals and even adjacent natural tooth structure under the ridge crest.
Even when the exact location of all of these structures is carefully determined, avoidance thereof by the thin blade portion requires great skill and manual dexterity. This is because in prior art implants of this type the blade is designed to be driven into the bone to a depth at which the projecting or head portion is generally spaced from the ridge crest above the incised tissue. Thus, with a blade of a given dimension, it is possible to drive the blade into the bone several millimeters more than intended and thereby, for example, perforate a sinus cavity or impinge on a nerve. Not only is the depth of insertion difficult to control but it is also rather difficult to measure with the accuracy required.
Moreover, even if no damage to other structures is done, this type of overseating is not easily correctable. A slight retraction of the blade invariably results in a loose fit. Consequently, the implant must usually be completely removed and replaced by a new implant having a thicker blade to provide a modicum of initial retention in the already tapped groove.
Another important drawback of prior art implants of this type is that the initial retention immediately after insertion, while better than that 'of previous types of implants, still leaves much to be desired. Thus, cementing of the final prosthesis to the upstanding support must be delayed at least seven days, during which time the implant may loosen and/or shift position before sufficient bone regeneration has taken place. As a result, it is often necessary to temporarily splint the implant so as to lesson the chance of loosening, shifting or loss of stability.
Finally, the number and variety of designs of blade implants has thus far been limited. Presently available designs fail to account sufficiently for the anotomical variations that exist in both jaws or the variations in available bone depth in different areas of the mouth. As a result the use of currently available blade implants for example in areas of shallow bone depth and/or sinus cavities has not been feasible.
It is a primary object of the present invention to provide an improved endosteal implant of the vented blade type in a variety of configurations having improved features designed to eliminate the above mentioned drawbacks.
lt is a further object of the present invention to design an improved blade implant including a novel blade configuration adapted to provide excellent retention and stability immediately upon insertion thereby considerably expediting tissue healing and bone regeneration.
It is another object of the present invention to design an endosteal blade implant provided with means to accurately and positively limit depth of insertion within the jawbone and to provide a locking action in that fully inserted position.
It is yet another object of the present invention to provide an improved vented blade implant having means to accurately measure depth of insertion to extremely close tolerances.
It is still a further object of the present invention to provide a blade implant of the type described having a unique shoulder configuration beneath the supporting head adapted to lockingly seat in a countersink in the tapped groove on the ridge crest, thereby to positively limit insertion depth and provide increased lateral stability immediately after insertion.
It is yet another object of the present invention to provide a blade implant having the above improved features in a plurality of novel design contours specifically adapted to relate to the borders of the various anatomical structures encountered in both jawbones, and having a blade edge configuration designed for easy insertion and rapid healing of tissue and bone regeneration.
To these ends, the present invention provides a blade implant comprising a thin vented blade portion tapered to a razor sharp edge at one end and having one or more necks extending from the other end and mounting one or more narrow supporting heads. The blade portions along their entire side surfaces are toothed to provide absolute initial retention. A variety of tooth configurations are provided, the appropriate design depending upon the properties of the jawbone in the particular area of the mouth and/or the particular patient. For maximum retention in shallow depths and/or weak bone, a staggered tooth configuration has been found particularly effective.
The head portion is designed with an increased height, taper and a faceted configuration which insures excellent crown retention. The head portion in accordance with the new design concept is adapted to originate at the ridge crest. For this purpose there is provided a uniquely designed bevelled shoulder portion designed to solidly seat in a countersink in the bone groove. This feature not only positively prevents overseating but also provides an immediate source of lateral stability which contributes to rapid and uneventful healing and bone regeneration in addition to providing the patient with a bitter feel for the life of the implant.
The implant is provided in a wide variety of blade contours carefully designed to accommodate the various anatomical structures, such as sinus cavities and adjacent tooth structures, commonly encountered, while at the same time providing rounded sloping and angled blade and vent contours found from clinical experience to cause the least trauma to tissue and bone.
To the accomplishment of the above and to such other objects as may hereinafter appear, the present in vention relates to vented blade implants as defined in the appended claims and as described herein with reference to the accompanying drawings, in which:
FIG. 1 is a perspective view of one embodiment of our improved cndosteal implant having the improved design features of this invention;
FIG. 2 is an enlarged front plan view of a second embodiment of our improved implant;
FIG. 3 is a fragmentary illustration of another embodiment of our improved implant properly inserted in the lower jawbone of the patient, the bone being partially broken away and the artificial tooth structure being illustrated in broken lines;
FIG. 4 is a fragmentary front plan view of still another form of our improved implant embedded in the upper jawbone of the patient in the area of the sinus cavity;
FIG. 5 is a top plan view of the implant of FIG. 2 showing the faceted structure of the crown supporting head structure;
FIG. 6 is a cross sectional view taken along the line 6-6 of FIG. 2;
FIG. 7 is a fragmentary cross sectional view on an enlarged scale of one form of tooth configuration which may be used with the present implants;
FIG. 8 is an enlarged cross sectional view similar to FIG. 7 of a second form of tooth configuration;
FIGS. 9, l0 and 11 illustrate various tooth undercut inclinations which may be used with the tooth configurations of FIGS. 7 and 8; and
FIGS. 12-27 are front plan views in the form of silhouettes of a sampling of the various plate contours and configurations which have been found useful.
Referring to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, a representative embodiment of our improved implant is illustrated in perspective in FIG. 1. As there shown the implant generally designated 10 comprises a unitary metalic structure including an implant portion 12, a supporting head 14 and a linking or neck portion 16 integral with and connecting implant portion 12 to head portion 14. The implant is preferably cast in pure titanium. Implant portion 12 is in the form of a relatively thin blade tapering to a relatively sharp knife edge 18 adapted to be driven into the patients jawbone. The blade 12 further includes a series of openings or vents 20 in its side walls 22 designed to facilitate bone regeneration therethrough. Linking portion 16 comprises an upstanding neck formed integral with blade 12, extending upwardly from the upper surface 17 of the blade and upon the upper end of which the crown supporting head 14 is integrally formed.
As illustrated in perspective in FIG. 1 that head is a relatively massive, multi-faceted body generally tapered in the direction away from neck portion 16. More particularly, as best illustrated in FIG. 2, wherein two such supporting heads 14 are shown, that body in accordance with our improved design includes inclined shoulder surfaces 26 extending upwardly and outwardly from the neck 16. In the embodiment illustrated, four such inclined shoulder surfaces 26 extend upwardly from the front, rear and side surfaces of the neck 16, said surfaces being generally in the shape of parallelograms connected at their corners by triangular surfaces 28 (see FIGS. 5 and 6) thereby to define a polyganol base line 30 generally in the form illustrated in FIG. 5 from which the crown supporting head extends upwardly. As best shown in FIGS. 2 and 5, that head comprises a plurality of inwardly inclined trapazoidal side surfaces 32 intersecting shoulder surfaces 26 and 28 at base line 30 and extending upwardly generally in the form of a pyramid. That pyramid is truncated by a generally horizontal top surface 33.
As best shown in FIGS. 2 and 6, the blade 12 is provided on both side surfaces 22 with a series of bone engaging teeth generally designated 34 extending in generally equally spaced parallel arrangement along the entire length of the blade and following the contour of the blade edge 18. In the preferred embodiment there shown and also illustrated in an enlarged cross sectional view in FIG. 7, those teeth are staggered on oppositeside surfaces 22. Alternatively, the teeth 34 may be formed generally in registration on opposite side surfaces 22 of the blade 12 in the form of an in verted Christmas tree as illustrated in section in FIG. 8. Moreover, the incline or shape of the teeth 34 may be varied to suit the individual circumstances.
Three such exemplary tooth configurations are illustrated in enlarged profile in FIGS. 9ll, but the possibilities are virtually endless. The tooth profile of FIG. 9 shows a sharp tooth edge 36 defined by the tooth sur face 38 inclined sharply downwardly (toward the blade edge) and inwardly. This configuration provides maximum initial depth retention as a result of the sharp tooth edge 36, but the resulting narrow crevice 40 is least conducive to rapid bone regeneration. Conversely, the oppositely inclined tooth surface 42 illustrated in FIG. 11 results in the other extreme-it provides relatively poor initial retention as a result of the poor gripping action of tooth edge 44 but is conducive to rather rapid bone regeneration within the wide crevice 46. The profile illustrated in FIG. represents a comprise between the two extremes, surface 48 being generally horizontal and defining a moderately sharp tooth edge 50 for reasonably good initial retention and a moderately wide crevice 52 for reasonably rapid bone regeneration. It will be appreciated that various other tooth shapes are possible with various curved or serpentine tooth profiles. Which particular tooth shape or profile used and whether or not the staggered or inverted Christmas tree configuration is used will depend upon the dentists judgment as to the condition of the patients jawbone in the particular implant area considered. Thus where the bone is strong and dense initial retention is of less importance than rapid bone regeneration. Moreover, in such a case the staggered configuration of FIG. 7 will facilitate insertion as it provides a narrower overall cross section. Conversely, if the bone is weak and/or porous and/or limited bone depth is available, initial retention is of primary importance and the profile of FIG. 9 will provide the increased initial retention required. In addition, particularly where available bone depth is limited, the inverted Christmas tree configuration of FIG. 8 provides increased lateral stability.
The advantages of the improved design features of our implant described herein will be appreciated from a consideration of the following technique for insertion into the patient's jawbone. After suitable x-rays have been taken, an incision is made by a sharp scalpel along the fibromucosal tissue 53 in the area where the implant is to be inserted (see FIG. 6). The incision is made along the alveolar crest so that the tissue may be retracted to expose sufficient bone without tearing it. The soft tissue is then retracted preferably with a periosteal elevator to expose the bone 56. A narrow groove is then cut in the cortical layer of the bone at the crest of the ridge 55. Prior to our new implant design the purpose of this groove was merely to provide a stable starting position for the subsequent tapping of the blade portion of the implant into the bone. Accordingly, that groove need only have been wide enough to accommodate the relatively sharp blade edge and deep enough to prevent slipping of that blade edge laterally along the ridge crest. In accordance with our new design that groove is now preferably formed with oppositely inclined chamfered surfaces 54 at the ridge crest generally in the form of a countersink accurately dimensioned to snugly receive the inclined bevelled shoulder surfaces 26 of the head portion 14 in a manner best illustrated in FIG. 6. For this purpose a tool having a corresponding inclined edge surface may be provided. The depth of the actual groove should be no more than 7 millimeters and will depend upon the condition of the bone and the particular profile of the implant utilized. The properly chosen blade implant is then placed with its sharp edge 18 inserted in the groove and a suitable instrument, preferably a plastic headed mallet applied to the upper surface 33 of the head 14, is used to tap the implant into the alveolar bone to the desired depth.
In order to facilitate monitoring of the insertion depth by the dentist or oral surgeon, the head 14 is preferably provided with a plurality 'of parallel equally spaced score lines 57 extending along surfaces 32. In the preferred embodiment these score lines 57 are accurately spaced one millimeter apart so that the insertion depth may from time to time be accurately measured. Thus in the event the patient experiences unusual pain or discomfort at a particular point in the insertion process, the depth of insertion may be accurately plotted on the x-ray to determine if the blade has impinged on any extraneous anatomical structures.
Insertion to the proper final depth is insured by the provision for accurate seating of inclined shoulder surfaces 26 on the countersunk surfaces 54 of the initial groove in the ridge crest. In addition to insuring accurate depth of insertion, this feature considerably enhances the initial retention, lateral stability and general feel of the device immediately after insertion. Moreover, proper seating of these shoulder surfaces insures that the blade is inserted substantially vertically.
The incised tissue is then closed preferably by the use of interrupted sutures along the base line 30 of the head or heads 14 of the implant. The sutures may be removed after approximately 5-7 days and the denture is then cemented directly into position over the exposed upwardly extending supporting head 14.
An additional advantage of the novel inclined shoulder seating arrangement just described is that it facilitates the fabrication of the denture. Thus in prior art implants, because the head was not designed to accurately seat in the bone and because of the difficulty in measuring depth of insertion, there was usually an undercut area between the implant head or post and the supporting neck. The material used for making impressions frequently would flow into this undercut area and, in the case of a relatively hard material such as plaster of paris, would lock around the neck. It will be appreciated that the countersink seating feature of the present invention virtually eliminates this problem and almost any impression material chosen will work satisfactorily for constructing the artificial denture. In addition, the multifaceted long and narrow tapered head 14 considerably contributes to easier construction and better retention of the artificial tooth structure thereon.
Typical implants constructed in accordance with this invention are shown properly inserted in a patients jawbone in FIGS. 3 and 4. FIG. 3 illustrates a relatively shallow blade, double-headed implant similar to that shown in FIG. 2 inserted in the lower jawbone of the patient. Each of the heads 14 is shown mounting one artificial tooth structure illustrated in broken lines and generally designated 60. It will be appreciated that the depth and contour of the blade portion is specifically designed to conform closely to the contour of the longitudinally extending anatomical structure schematically illustrated and generally designated 62 which may be the inferior alveolar canal comprising nerves and blood vessels.
FIG. 4 shows a somewhat different design of a blade implant also having two heads or posts 14. That implant is shown properly inserted in the upper jawbone adjacent a sinus cavity 64 and as illustrated has a depth and contour conforming relatively closely to that sinus cavity.
It will be noted in both FIGS. 3 and 4 that the upper surface of the blade 17 is embedded several millimeters into the bone thereby allowing for substantial bone regeneration at the ridge crest and increased retention.
A representative sample of blade shapes and contours which may be provided in accordance with the present invention is illustrated in FIGS. l222. The various areas of the mouth and the various bone conditions to which the illustrated implants are best suited will be immediately apparent to dental surgeons and dentists skilled in the art and accordingly they will not be described in detail herein. Suffice it to say that the shape and size of the knife edge and vent openings in all of the illustrated embodiments have been carefully designed from clinical experience to provide the maximum retention, bone regeneration and stability for various bone conditions and locations with a minimum trauma to the bone and/or tissue upon insertion.
It will be appreciated from the foregoing that we have designed a number of major improvements in endosteal implants. The beveled shoulder surfaces at the underside of the supporting head provides considerably more lateral stability than has heretofore been possible and in addition serves as a safety stop and lock mechanism for positively and accurately limiting depth of insertion. In addition that depth may be accurately monitored during the insertion process by means of the conveniently positioned accurately spaced score lines on the supporting head.
The combinations of blade edge contours and tooth profiles for the blade portion is adapted to afford the dentist or oral surgeon with a structure best suited for the particular situation encountered thereby to give the maximum combination of initial retention and bone regeneration with a minimum of trauma to the bone and/or tissue.
Finally, the multifaceted head portion facilitates crown construction and retention by providing a relatively long narrow tapered support originating at the ridge crest.
While only a limited number of embodiments of this invention have been herein specifically disclosed, it will be apparent that many variations may be made thereto without departing from the spirit'and scope of the invention, as defined in the following claims.
1. In an oral implant for permanently implanting an artificial tooth supporting structure in the jawbone of a patients mouth, comprising a relatively thin blade portion having a sharp edge adapted to be inserted into a shallow longitudinal groove along the ridge crest ofa patients jawbone and thence driven directly into the jawbone to a suitable depth, and a comparatively massive support portion substantially wider than said blade portion, operatively connected thereto and adapted to extend therefrom outwardly of said jawbone for mounting said artificial tooth structure, the improvement comprising a shoulder surface on the underside of said support portion nearest said blade portion, said shoulder surface being inclined to said blade and being adapted to seat on a correspondingly inclined chamfered surface at the mouth of said groove, whereby engagement of said inclined shoulder surface with said chamfered bone surface provides an automatic limitation on insertion depth and increased lateral stability.
2. The implant of claim 1, wherein two such inclined shoulder surfaces are provided on the underside of said support portion, said shoulder surfaces being adapted to seat on opposing chamfers at the mouth of said groove in said bone.
3. The implant of claim 2, wherein said support portion, adapted to extend outwardly of said bone, comprises a plurality of angularly inclined planar surfaces.
4. The implant of claim 3, wherein said support portion is tapered in a direction outwardly of said bone.
5. The implant of claim 4, wherein said support portion adapted to extend outwardly of said bone is in the form of a truncated pyramid.
6. The implant of claim 1, wherein said support portion, adapted to extend outwardly of said bone, comprises a plurality of angularly inclined planar surfaces.
7. The implant of claim 6, wherein said support portion is tapered in a direction outwardly of said bone.
8. The implant of claim 7, wherein said support portion adapted to extend outwardly of said bone is in the form of a truncated pyramid.
9. The implant of claim I, further comprising a neck portion operatively connecting said blade portion to said support portion, said inclined shoulder surface being inclined to said neck portion and extending upwardly and outwardly therefrom.
10. The implant of claim 9, wherein two such inclined shoulder surfaces are provided on the underside of said support portion, said shoulder surfaces being adapted to seat on opposing chamfers at the mouth of said groove in said bone.
11. The implant of claim 10, wherein said support portion, adapted to extend outwardly of said bone,
comprises a plurality of angularly inclined planar surfaces.
12. The implant of claim 11, wherein said support portion is tapered in a direction outwardly of said bone.
13. The implant of claim 12, wherein said support portion adapted to extend outwardly of said bone is in the form of a truncated pyramid.
14. The implant of claim 1, wherein said blade portion is provided with a plurality of bone engaging teeth extending longitudinally therealong generally parallel to said sharp edge on opposite sides of said blade.
15. The implant of claim 14, wherein said teeth on said opposite sides of said blade are in staggered relationship.
16. The implant of claim 15, wherein two such inclined shoulder surfaces are provided on the underside of said support portion, said shoulder surfaces being adapted to seat on opposing chamfers at the mouth of said groove in said bone.
17. The implant of claim 16, wherein said support portion, adapted to extend outwardly of said bone, comprises a plurality of angularly inclined planar surfaces.
18. The implant of claim 17, wherein said support portion is tapered in a direction outwardly of said bone.
19. The implant of claim 18, wherein said support portion adapted to extend outwardly of said bone is in the form of a truncated pyramid.
20. The implant of claim 1, wherein said head portion is provided with a plurality of score lines extending generally in a direction transverse to the direction of insertion of said blade, said score lines being equally spaced along the surface of said support portion to facilitate accurate measurement of depth of insertion.
2]. In an oral implant for permanently implanting an artificial tooth supporting structure in the jawbone of a patients mouth, comprising a relatively thin blade portion having a sharp edge adapted to be inserted into a shallow longitudinal groove along the ridge crest of a patients jawbone and thence driven directly into the jawbone to a suitable depth, said blade portion having one or more vent openings therein for the regeneration of bone therethrough, and a comparatively massive support portion substantially wider than said blade portion, operatively connected thereto and adapted to extend therefrom outwardly of said jawbone for mounting said artificial tooth structure, the improvement comprising a plurality of bone engaging teeth on opposite sides of said blade portion extending longitudinally therealong generally parallel to said sharp edge, said sharp edge and said bone engaging teeth extending generally parallel to the ridge crest.
22 The implant of claim 21, wherein said teeth on said opposite sides of said blade are in staggered relationship.
23. The implant of claim 21, wherein said sharp edge on said blade portion is curved.