Dental implant and device with a dental implant

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TECHNICAL FIELD

The invention relates to a dental implant. The implant can be used as an intraosteal implant and can be inserted into the bone of an upper or lower jaw. A secondary part can be fastened to the implant to serve for holding, and/or for the construction of, a dental prosthesis, i.e., a prosthesis with a single artificial tooth or a number of artificial teeth. The implant can furthermore serve to hold a special superstructure forming, for example, an entire single artificial tooth.

STATE OF THE ART

A device disclosed in DE 41 27 849 A has an implant and a secondary or holding part. The implant has an axial blind bore with a polygonal section. The secondary part has a polyhedral section fitting into the polyhedral section of the blind bore. The polyhedral sections are configured as dodecahedral sections, so that the secondary part can be set selectively in any one of twelve positions, i.e., can be joined non-rotationally to the implant. In many cases, however, it would be desirable if the secondary part could be joined in only a single, clearly defined position to the implant. Also, the dodecahedral mating sections provide but a relatively imprecise definition of the rotational position due to the necessary clearance. The polyhedral section of the blind bore is rather long and extends all the way to the mouth of the blind bore, so that the secondary part is never held well and accurately above the blind bore. Also, the secondary part is glued into the implant and accordingly can no longer be removed from it.

A device disclosed in EP 0 685 208 A likewise has an implant and a secondary part. The implant has an axis and a bore coaxial with it which has a tapering section and an internal thread. The secondary part can be inserted partially into the bore in the implant and has an external thread which can be driven into its internal thread. The secondary part is rotated about its axis when it is screwed into the implant, until it contacts with a tapered section the tapered section of the bore. The rotational position in relation to the axis of the secondary part which results in the assembled state depends on the production tolerances and on the torque with which the secondary part is screwed into the implant. So this implant does not permit any precise setting of the rotational position of a secondary part reaching into the bore in the implant.

DE 195 34 979 C has disclosed a device with an implant and a spacer sleeve. The implant has an axial blind bore. Its inside surface is provided with six grooves distributed about the axis of the implant. The spacer sleeve reaches into the blind bore of the implant and has lugs engaging in its grooves, so that the spacer sleeve can be set in six different rotational positions. This implant thus does not define any single, definite rotational position. Also the spacer sleeve is guided laterally only in a short cylindrical guiding portion of the bore, which has a relatively small diameter, and is supported against forces directed approximately squarely to the axis of the implant. If such forces act on a dental prosthesis held by the spacer sleeve, a long lever arm is created between the point of attack of these forces and the guiding portion of the bore, so that very great torques must be transferred from the spacer sleeve to the implant in the guiding portion of the blind bore. This, combined with the small dimensions of the guiding portion, results in a great danger that the prosthesis under stress will perform small movements--so-called micromovements--with respect to the implant, and thus a failure of the dental treatment is caused.

BRIEF DESCRIPTION OF THE INVENTION

The invention is therefore addressed to the problem of creating a dental implant which eliminates the disadvantages of the known implants, and especially makes it possible to connect to the implant a secondary and/or superstructural part, depending on its shape and intended use, in only one, clearly defined rotational position or in one which can be selected from any of several possible rotational positions.

This problem is solved according to the invention by a dental implant with an axis and a bore coaxial with this axis for fastening a secondary and/or superstructural component, wherein the bore has a positioning section with projections and interstices alternating with one another around the axis, and the dental implant is characterized in that the interstices have a plurality of first interstices of equal size and a second interstice which in at least one direction has a larger dimension than the first interstices.

The invention further relates to a device with a dental implant and with a secondary and/or superstructural part, the device according to the invention being characterized in that it has a connecting section intended to reach into the bore in the implant and to be fastened in the latter.

Advantageous embodiments of the implant and the device will appear from the dependent claims.

The first and second interstices of the dental implant according to the invention make it possible to fasten to one and the same implant secondary and/or superstructural components of optionally different configuration, which, depending on their configuration, are able to assume only a single rotational position defined by the positioning section of the implant, or which can assume a rotational position selected from several possible rotational positions, or whose rotational position is not defined by the positioning section.

The implant is preferably elongated and generally rotationally symmetrical with its axis. The bore is preferably a blind bore and has a mouth situated at one end of the implant. Each interstice of the implant is preferably straight and parallel as well as symmetrical with a plane passing through the said axis and through the middle of the groove in question. The positioning section of the implant is furthermore generally cylindrical, for example, so that the projections present between the interstices of the implant have an apex lying in a cylindrical surface coaxial with the axis. The positioning section of the implant, however, can possibly be generally conical instead of cylindrical, narrowing away from the mouth of the bore, and can have projections which separate the interstices from one another and have apexes lying in a conical surface.

The positioning section of the implant preferably defines a pitch circle, both in the case of generally cylindrical and in the case of generally conical shape, which is coaxial with the axis and conforms with the apexes of the projections of the implant. In a preferred embodiment, the second interstice is wider and/or deeper than the first interstices. The first interstices adjacent one another are at equal distances apart as measured along the pitch circle, and together they define a pitch circle division or--simply--a division. For clarification let it also be noted that the division is equal to the nth part of a full circle, n being a whole number and preferably at least 6, or better at least 10, and amounting to no more than 72, for example. The second, wider and/or deeper interstice has a dimension measured along the pitch circle that is preferably greater than one division, for example approximately or exactly equal to the sum of the dimension of a first interstice measured along the pitch circle and of one whole division or several whole divisions.

A secondary part designed to be fastened to the implant can have an inside section or connecting section, and an outside or head section. When the secondary part is fastened to the implant the inside or connecting section is situated in the bore in the implant and the outside or head section outside of the implant. The secondary parts can be configured differently according to the intended use and the medical indications. The inside or connecting section of the secondary part can have, for example, a positioning section with projections distributed along its circumference, and separated from one another by interstices. When the secondary part is fastened to the implant, the projections of the implant and of the secondary part can then engage interstices of the other part and thereby establish a rotational position of the secondary part with respect to rotations about the axis defined by the bore in the implant. In one possible embodiment of the secondary part, all projections of the secondary part have equal shapes and dimensions, so that the secondary part can be fixed in different rotational positions on the implant. The rotational position of the secondary part is thus optional and variable step by step, while each selectable rotational position is defined by the intermeshing projections and grooves of the implant and secondary part, and the angle of rotation between adjacent rotational positions is equal to the dividing angle established by the division of the equally configured (first) interstices. This method of joining a secondary part to the implant is referred to hereinafter as the multipositioning of the secondary part.

The secondary part can furthermore have a projection which in at least one direction has a greater dimension than the first interstices of the implant and is configured such that it can enter in the second interstice, but not in the first interstices of the implant. This projection of the secondary part can especially be wider than the first interstices of the implant and/or have a height that is greater than the radial depth of the first interstices of the implant. The positioning section of the secondary part then preferably has, in addition to the said projection, narrower projections for engaging the narrower first interstices of the implant, but possibly can have only just the projection engaging the second, wider and/or deeper interstice of the implant. The secondary part can then be joined to the implant only in a single rotational position as regards rotations about the axis defined by the implant. This way of joining a secondary part to the implant will be referred to hereinafter also as single positioning of the secondary part.

The secondary part, however, can also be made without a positioning section, and can be so configured that, when inserted into the bore of the implant and after it is fastened to the latter, it will not enter into the interstices of the implant. The secondary part is then continuously rotatable upon insertion into the bore in the implant, until the secondary part is fastened to the implant.

Each interstice in the implant is defined preferably at least partially by flats which are approximately or precisely parallel to a straight line passing radially to the axis through the center of the interstice in question, or form with such a straight line an angle of at most 60.degree. and preferably no more than 45.degree.. Furthermore, each interstice has, for example, two substantially planar lateral surfaces. The interstices can be approximately V-shaped in cross section, or they can have also a base surface and be approximately U-shaped. The interstices can furthermore be substantially completely curved, and form an arc, for example, which is no more than equal to a semicircle and, for example, smaller than a semicircle. The projection, or every projection, of the secondary part and implant engaging in an interstice has a certain free play, so that in spite of possible manufacturing inaccuracies and in spite of dimensional changes caused by temperature changes, the projection can be inserted easily into the interstice. The free play of a projection, measured tangentially to the above-mentioned pitch circle is preferably made so small that the secondary or superstructural part can be turned back and forth by no more than an angle amounting preferably to no more than 2.degree., or better 1.degree., or even no more than 0.5.degree..

The blind bore of the implant has preferably an internal thread serving for the removable attachment of the secondary part. If the secondary part has a positioning section with a projection or, preferably, a plurality of projections, the secondary part can be releasably fastened to the implant with an external thread which can be screwed into the internal thread of the implant. The fastening means can consist, for example, of a screw with a head urged against a surface of the secondary part, or of a headless screw which can be threaded into the secondary part. The headless screw can then have, in addition to the external thread which can be screwed into the internal thread of the implant, an external thread which can be screwed into an internal thread in the secondary part, and one of the external threads can be right-handed, for example, and the other left-handed, and/or the two external threads can have different pitches. To attach a secondary part to provide positioning, therefore, only a single additional element is needed, namely the said fastening means. If the secondary part, however, has no projection designed to engage a positioning groove in the implant, the secondary part can either also be fastened releasably to the implant, likewise with a separate fastening means of the kind described, or it may be provided with an external thread which can be screwed into the internal thread of the implant and consists, together with the remaining sections of the secondary part, of a one-piece body. Possibly a secondary part can also be provided which is fastened to the implant, not by screwing, but one which when used is first inserted releasably into the hole in the implant, and then, when it must no longer be removed, it is cemented or glued in the bore in the implant. The bore in the implant can then nevertheless have an internal thread so that the same type of implant can also be used to accommodate a threaded secondary part. If desired, however, the internal thread can be omitted from the implant. The secondary part can be joined securely and free of micromovements to the implant by the above-described screwing, cementing or gluing methods, so that in a physiological environment, it will not loosen due to micromovements.

A firm manufacturing implants according to the invention can, for example, also manufacture different variants of secondary parts to be fitted to the implants and offer one type of implant and various secondary parts to dentists and dental clinics and the like. Then, for example, a superstructure serving for the formation of a dental prosthesis can be built unreleasably on the secondary part or can be fastened releasably to the latter. Also, two or more devices each with an implant and a secondary part can serve for fastening a bridge or a dental prosthesis containing a plurality of teeth.

As already mentioned, instead of a secondary part, a special superstructural part can be fastened to an implant. Such special superstructural part can then, instead of the firm producing the implants, be custom made by a dental technician for special purposes and/or for a specific patient. What has been described above concerning the joining of a secondary part to the implant can then apply in a substantially similar way to the attachment of a special superstructural part to an implant.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the invention is explained below with the aid of embodiments represented in the drawings. In the drawings:

FIG. 1 shows an axial section taken through a part of an implant in which the bore has a positioning section in the vicinity of the bottom end of a cylindrical section,

FIG. 2 an enlarged cross section taken through the implant of FIG. 1,

FIG. 3 an angular elevation of the implant of FIGS. 1 as well as 2,

FIG. 4 an angular elevation of an implant with a positioning section disposed as in FIG. 1, but of a different configuration,

FIG. 5 an angular elevation of an implant with a positioning section arranged at its upper end,

FIG. 6 an angular elevation through an implant whose positioning section is arranged below the narrower end of a tapered section of the bore,

FIG. 7 an axial section taken through a straight secondary part with a positioning section arranged in the vicinity of the lower end,

FIG. 8 an enlarged cross section taken along line VIII--VIII of FIG. 7 through the secondary part drawn therein and configured for multipositioning,

FIG. 9 a cross section similar to FIG. 8 taken through a secondary part for single positioning,

FIG. 10 an axial section taken through a bent secondary part,

FIG. 11 an axial section taken through a secondary part fitting the implant of FIG. 5,

FIG. 12 an axial section taken through a straight secondary part with an internal thread for fastening a stud bolt,

FIG. 13 an axial section taken through a secondary part whose internal and connecting portion has a tapered external surface section,

FIG. 14 an angular view of a bent secondary part with an internal thread for fastening a stud bolt,

FIG. 15 an elevation of a screw,

FIG. 16 an elevation of a stud bolt with two threads,

FIG. 17 an elevation of another stud bolt,

FIG. 18 an angular view of a secondary part according to FIGS. 7 and 8, and of a screw inserted in the latter,

FIG. 19 an axial section taken through a device with an implant according to FIGS. 1 to 3 and the parts according to FIG. 18,

FIG. 20 a cross section taken along line XX--XX of FIG. 19 through the device seen in the latter.

FIG. 21 an angular view of a straight secondary part according to FIG. 9 and of a screw inserted in the latter,

FIG. 22 a cross section through a device with an implant according to FIGS. 1 to 3 and the parts according to FIG. 21,

FIG. 23 an angular view of a device with an implant according to FIG. 4, a secondary part configured for single positioning, and a stud bolt,

FIG. 24 an angular view of a bent secondary part for multipositioning, and a screw,

FIG. 25 an axial section taken through a device with an implant according to FIG. 4 and parts according to FIG. 24,

FIG. 26 a cross section taken along line XXVI--XXVI of FIG. 24 through the device shown therein,

FIG. 27 an axial section taken through a device with an implant according to FIG. 6 and a bent secondary part according to FIG. 14,

FIG. 28 an angular view of a device with an implant according to FIG. 6 and a straight secondary part,

FIG. 29 an angular view of a device with an implant according to FIGS. 1 to 3 and a straight secondary part without positioning section, and

FIG. 30 a cross section taken through the device according to FIG. 29.

DESCRIPTION OF PREFERRED EMBODIMENTS

The dental implant 1 represented in FIGS. 1 to 3 is elongated as well as generally rotationally symmetrical with an axis 2 and has at the top a cylindrical, smooth circumferential surface 10. The lower part of implant 1, which is not seen in FIGS. 1 and 3, can be configured, for example, in any known or novel manner, and have, for example, a smooth cylindrical exterior or a screw thread. Also, the unseen lower part of the implant can have, for example, a cavity open at the bottom or a solid cross section at the bottom end.

The implant 1 has at the upper end an implant shoulder 11 which is formed by a planar annular surface radial to the axis 2. The implant is provided with a stepped blind bore 12 generally coaxial with the axis 2. This bore has a mouth 13 situated at the upper end of the implant and surrounded by the inner margin of the annular surface forming the shoulder 11, and downward from the latter a cylindrical main section 14, a positioning section 15, a short, generally cylindrical recess 16, a radial and/or inclined shoulder 17, a narrower cylindrical section 18, and a section 19 with an internal thread 20, in that order. The axial dimension of the positioning section 15 amounts, for example, to approximately 0.5 mm to 1 mm. The diameter of the recess 16 is equal to that of the cylindrical main section 14. The diameter of the narrower, cylindrical section 18 is at least or approximately equal to the maximum diameter of the internal thread 20. Moreover, let it be noted that the narrower cylindrical section 18 could possibly be omitted and the internal thread could directly adjoin the recess 16.

As it can be seen especially clearly in FIGS. 2 and 3, the positioning section 15 has positioning projections 23 and positioning interstices 24, 25 alternating with one another along the circumference. The positioning projections 23 are all equally configured, extend inwardly toward the axis 2 from the cylindrical surface defined by the cylindrical main section 14, taper inwardly in cross section toward their apex, and are approximately V-shaped or triangular in cross section. The positioning interstices have a plurality of equally shaped as well as equally dimensioned, especially of equal width, namely narrow, first positioning interstices 24 and a single, wider second positioning interstice 25. Each first positioning gap 23 consists of a groove or notch of approximately V-shaped cross section and has two substantially planar flanks which slope away from one another inwardly from its base toward the axis 2. The wider second positioning gap 25 has a planar or slightly curved base surface and two lateral surfaces inclined inwardly therefrom away from one another. The lateral surfaces of the gaps and the apexes of the projections are straight in axial sections and run parallel to the axis 2. The apexes of the projections 23 define a pitch circle 27 and lie on a cylindrical surface. The bases of the interstices 24, 25 together also define a cylindrical surface which coincides approximately or precisely with the cylindrical surfaces of the main section 14 and of the recess 16. The narrow first positioning interstices 24 adjacent one another are all at the same distance apart and define a division on the pitch circle 27, for example a 10.degree. or 36-pitch division. The wider, second positioning interstice 25 is formed by the omission of one projection 23 or of two or even more projections 23 adjacent one another.

The dental implant 31 seen in FIG. 4 is very similar to implant 1, defines an axis 31 and has an implant shoulder 41, a blind bore 52 with a mouth 53, a cylindrical main section 54, a positioning section 55 and an internal thread 60. The positioning section is arranged similar to the positioning section 15 and has positioning projections 63 and positioning interstices 64, 65 following one another alternately along its circumference. The positioning projections 63 are again all of the same configuration. The positioning interstices 64, 65 have a plurality of first, narrow positioning interstices 64 and a second, wider positioning interstice 65. Each positioning projection 63 consists of a cog and has an apical surface that is arcuate in cross section. The apical surfaces of the projections form parts of a cylindrical surface coaxial with the axis of the implant 31 and they define a pitch circle. The second, wider positioning interstice 65 is formed by the omission of one positioning projection 63. Each positioning interstice 64, 65 is approximately U-shaped in cross section and/or quadrangular, and has two lateral surfaces which are planar and approximately or precisely parallel to a plane running through the axis 32 and the center of the positioning interstice in question. Also, each interstice 64, 65 has a base surface which is parallel to the axis 32 as well as arcuate or straight in cross section, and approximately coincides with the surface of the main section 54. The first, narrow positioning interstices 64 together define a division, for example a 30.degree. or 12-pitch division.

The dental implant 71 seen in FIG. 5 has an axis 72, an implant shoulder 81 and a blind bore 82 with a mouth situated at the upper end of the implant and surrounded by the implant shoulder 81, a cylindrical main section 84, a positioning section 85 and an internal thread 90. The positioning section is situated approximately at the upper end of the implant between the mouth 83 and the cylindrical main section 84, and is separated from the latter by a recess 86. The positioning section has, for example, projections and interstices of a configuration similar to that of the positioning section 15 of implant 1, but could also be configured similar to the positioning section 55 of implant 31. The apexes of the projections of the positioning section define a cylindrical surface whose diameter is, for example, approximately or at least equal to that of the cylindrical main section 84.

The dental implant 101 represented in FIG. 6 has an axis 102. The circumferential surface of implant 101 has at the top a flaring section 102. At the lower end thereof a cylindrical section 10 adjoins it. The implant shoulder 11 is formed by a conical, upwardly tapering annular surface. The blind bore 112 has a mouth 113 surrounded by the implant shoulder 111 and from there on down a downwardly tapering, conical main section 114, a positioning section 115, a recess 116, a cylindrical section 118 and a section 119 with an internal thread 120, in that order. The positioning section 115 is configured to be, for example, similar to positioning section 55 of implant 31, but could be configured similar to the positioning section 15 of implant 1. Let it be noted that the apexes of the positioning projections 115 define a cylindrical surface, but could possibly define a conical surface.

The secondary part 201 represented in FIGS. 7 and 8 is generally rotationally symmetrical with an axis 202 as well as straight, and has at the bottom a generally cylindrical internal and connecting section 210 intended for insertion into an implant and for releasable connection therewith. This connecting section is provided near the bottom end 212 of the secondary part with a positioning section 215. The secondary part furthermore has an outside or head section 220 tapering conically upward from the internal or connecting section and intended for arrangement outside of the implant, and it forms the upper end 221 of the secondary part. The head section 220 extends radially beyond the connecting section 210 and, when these two sections are joined, it forms a shoulder 225 with an annular, radial, planar bearing surface. The secondary part 201 is provided with an axial through-bore 230. This bore is provided near the upper end 221 of the secondary part with an internal thread 231 and has downward therefrom a shoulder 232, a cylindrical seat 233 with an annular groove 234 arranged a little below the shoulder 25, a downwardly tapering conical section 235 and a downwardly flaring, conical section 236 which extends down to the bottom end 212 of the secondary part, in that order. The two conical sections 235, 236 together form a constriction 237. A portion of the internal connection section 210 is divided by axial slits 240 from the bottom end 212 into axial, elastic, resilient tongues 241 which can be spread apart against a restoring force. For example, there are four slits and tongues, but the number and depth of the slits 240 can be varied. The slits 240 reach from the bottom end 212 to beyond the constriction, approximately to the annular groove 234 serving to improve the ability of the tongues to spread, but are not to extend all the way to the shoulder 225.

The positioning section 215 is situated in the area of the tongues 241 and has axial grooves in the outside surface of the latter which form the positioning interstices 243, between which positioning projections 245 are present. The apexes of the latter lie in the cylindrical outside surface of the inner, connecting section 210. The interstices 243 and projections 245 are, except for the gaps at the slits 240, uniformly distributed along the circumference of the secondary part. The positioning interstices 243 are all of the same shape and dimensions, have the same spacing as the positioning projections 23 of implant 1 and are at least approximately complementary to the latter. The positioning projections 245 of the secondary part 201 are likewise all of the same shape and dimensions, have the same spacing as the first positioning interstices 24 of implant 1 and are at least approximately complementary to the latter. The positioning section 215 of the secondary part 201 permits--as will later be explained--the multipositioning of the secondary part 201 with respect to the implant 1. The secondary part 251 seen in FIG. 9 has an internal connecting section 260 with a positioning section 265 configured for single positioning, and an external head section 270. The positioning section 265 has positioning interstices 273 formed by axial grooves, a plurality of first, narrow, identically shaped positioning projections 275, and a second, wider positioning projection 276. The positioning interstices 273 and the first positioning projections 275 have the same spacing as the first positioning interstices 24 of implant 1. The second, wider positioning projection 276 can clearly be formed by omitting or bridging at least one interstice of two or possibly more adjacent first positioning projections. The positioning interstices 273 of the secondary part 251 are approximately complementary to the positioning projections 23 of implant 1. Also, the first positioning projections 275 and the second positioning projection 276 of the secondary part 251 are approximately complementary to the first positioning interstices 24 or second positioning interstice 25 of implant 1.

The bent secondary part 301 seen in FIG. 10 has two axes 302, 303, forming an obtuse angle with one another, an inner connecting section 310 generally rotationally symmetrical with the axis 302 and having a positioning section 315, and a tapering outside head section 320 which is generally rotationally symmetrical with the axis 303. The shoulder 325 present between the latter and the connecting section 310 is radial as well as at right angles to the axis 302. The secondary part 301 has an angled through bore 330 which has a portion extending through the connection section 310 and the lower part of