DENTAL IMPLANT

Abstract

The invention relates to a dental implant consisting of an anchoring body defined between an apical end and a cervical end, wherein said anchoring body is a body having a first predetermined length and, on the outer surface thereof and along the entirety of said first predetermined length, at least one thread, wherein said anchoring body has, over at least a coronal portion, a portion of said at least one thread that has a nominal diameter that is greater than an outer diameter of said anchoring body at a first ratio of 2.00 to 4.00, preferably 2.00 to 3.00.

Claims

1. A dental implant formed by an anchoring body defined between an apical end and a cervical end, said anchoring body being a body with a first predetermined length and having, on its outer surface and along all of said first predetermined length, at least one thread, wherein said anchoring body comprises, over at least a coronal portion of the implant, a portion of said at least one thread with a nominal diameter that is greater than an outer diameter of said anchoring body at a first ratio comprised between 2.00 and 4.00, preferably between 2.00 and 3.00.

2. The dental implant according to claim 1, wherein said anchoring body is at least partially substantially cylindrical.

3. The dental implant according to claim 1, wherein said anchoring body has a conical-cylindrical shape or conical shape with its taper converging toward said apical end.

4. The dental implant according to claim 1, wherein said coronal portion is defined by a side wall that has a first vestibular face and a second palatine face, said palatine face being in a position offset toward said cervical end relative to that of the vestibular face along a longitudinal axis traversing the anchoring body and connecting said first cervical end to said apical end.

5. The dental implant according to claim 1, wherein said anchoring body has, at its apical end, at least one tapping notch made up of at least one longitudinal recess, preferably arranged from the apical end toward the cervical end of the anchoring body.

6. A prosthetic assembly comprising: said implant according to claim 1; and a transgingival element arranged to be connected to the coronal portion of the anchoring body and intended to support a prosthetic element.

7. The prosthetic assembly according to claim 6, wherein said transgingival element is a cervix that protrudes from the cervical implant end and that is positioned in the extension of the coronal portion of the anchoring body.

8. The prosthetic assembly according to claim 6, wherein said transgingival element is a pier connected, preferably removably, by a connecting means to said coronal portion of the anchoring body.

Description

[0040] FIG. 1 illustrates a first embodiment of the implant according to the invention.

[0041] FIG. 2 illustrates a first embodiment of the prosthetic assembly according to the invention.

[0042] FIG. 3 illustrates a second embodiment of the prosthetic assembly according to the invention.

[0043] FIG. 4 illustrates a third embodiment of the prosthetic assembly according to the invention.

[0044] In the figures, similar elements bear the same reference.

[0045] FIGS. 1a and 1b illustrate a first embodiment of the implant 1 according to the invention. In these figures, the anchoring body 2 is identified with a first length L.sub.1 generally comprised between 10.00 mm and 15.00 mm, forming the implant defined by an apical end E.sub.a and a cervical end E.sub.c connected to one another by a longitudinal axis a.sub.L.

[0046] This longitudinal axis a.sub.L, which traverses the anchoring body 2 from the apical end E.sub.a toward the cervical end E.sub.c, corresponds to the rotation axis of a thread 4 present on an outer surface over the entire length of the anchoring body 2.

[0047] The thread 4 is a positive pitch thread, i.e., that screws in a drilling direction D when the screw is rotated clockwise around the rotation axis a.sub.L.

[0048] The anchoring body 2 has, over at least a coronal portion 3 that extends over a second length L.sub.2 from 2.00 mm to 5.00 mm, a portion of the thread 4 having a threading (with turns) with nominal diameter d.sub.n larger than an outer diameter d.sub.e of the anchoring body 2 at a first ratio R.sub.1=d.sub.n/d.sub.e comprised between 2.00 and 4.00, preferably between 2.00 and 3.90, advantageously between 2.00 and 3.80, more advantageously between 2.00 and 3.70, alternatively between 2.00 and 3.60, in one particular embodiment between 2.00 and 3.50.

[0049] Optionally, the first ratio R.sub.1=d.sub.n/d.sub.e is comprised between 2.00 and 3.40, preferably between 2.00 and 3.30, more advantageously between 2.00 and 3.20, alternatively between 2.00 and 3.10, optionally between 2.00 and 3.00.

[0050] Optionally, the first ratio R.sub.1=d.sub.n/d.sub.e is comprised between 2.00 and 3.00.

[0051] Preferably, the first ratio R.sub.1=d.sub.n/d.sub.e is comprised between 2.00 and 2.90, preferably between 2.00 and 2.80, advantageously between 2.00 and 2.70, more advantageously between 2.00 and 2.60, alternatively between 2.00 and 2.50, in one particular embodiment between 2.00 and 2.40.

[0052] Optionally, the first ratio R.sub.1=d.sub.n/d.sub.e is comprised between 2.00 and 2.30, preferably between 2.00 and 2.20, more advantageously between 2.00 and 2.10.

[0053] The first ratio R.sub.1=d.sub.n/d.sub.e is more preferably equal to 2.00 or 2.50.

[0054] The first ratio R.sub.1=d.sub.n/d.sub.e is still more preferably equal to 3.00 or 3.50.

[0055] The first ratio R.sub.1=d.sub.n/d.sub.e is still more advantageously equal to 4.00.

[0056] The length L.sub.2 corresponds to the mean thickness of the cortical bone of the jaw.

[0057] The nominal diameter is the diameter measured between two peak ends of the thread.

[0058] Preferably, the nominal diameter d.sub.n of the thread has a value comprised in a range from 2.50 mm to 6.00 mm, preferably in a range from 4.00 mm to 5.00 mm. The outer diameter D of the anchoring body 2 is preferably chosen in a range from 1.20 mm to 3.00 mm.

[0059] Preferably, the thread, having the ratio R.sub.1=d.sub.n/d.sub.e defined above, is present over at least the entire length L.sub.2 of the coronal portion 3 of the implant 1.

[0060] Advantageously, the thread, having the ratio R.sub.1=d.sub.n/d.sub.e defined above, is present over the entire length L.sub.1 of the implant.

[0061] The anchoring body 2 is preferably a solid body made from titanium or zirconium with a conical shape having a taper converging toward said apical end E.sub.a. In particular, the anchoring body 2 has an apical end outer diameter d.sub.Ea comprised between 1.50 mm and 2.00 mm and a cervical end outer diameter d.sub.Ec comprised between 2.50 mm and 3.00 mm.

[0062] The thread 4 is further characterized by a second ratio R.sub.2=n/L.sub.1 comprised between 0.50 mm.sup.−1 and 1.00 mm.sup.−1, preferably between 0.60 mm.sup.−1 and 1.00 mm.sup.−1, advantageously between 0.70 mm.sup.−1 and 1.00 mm.sup.−1, n representing a predetermined number of peaks 5 of the thread 4.

[0063] The ratio R.sub.2 therefore represents the density of peaks per unit of length of the implant. For example, for an implant with length L.sub.1 equal to 10.00 mm, a ratio R.sub.2 of 0.50 mm.sup.−1 means that over the length L.sub.1, a thread is formed comprising 5 peaks.

[0064] A ratio R.sub.2 of 1.00 mm.sup.−1 means that over a length L.sub.1 equal to 10.00 mm, a thread is formed comprising 10 peaks.

[0065] Advantageously, the thread 4 is further characterized by a third ratio R.sub.3=n/L.sub.2 comprised between 0.50 mm.sup.−1 and 1.00 mm.sup.−1, preferably between 0.60 mm.sup.−1 and 1.00 mm.sup.−1, advantageously between 0.70 mm.sup.−1 and 1.00 mm.sup.−1, n representing a predetermined number of peaks 5 of the thread 4.

[0066] The ratio R.sub.3 therefore represents the density of peaks per unit of length L.sub.2 of the coronal portion 3 of the implant. For example, for a coronal portion 3 with length L.sub.2 equal to 3.00 mm, a ratio R.sub.3 of 0.50 mm.sup.−1 means that over the length L.sub.2, a thread is formed comprising 1.5 peaks.

[0067] A ratio R.sub.3 of 1.00 mm.sup.−1 means that, over a length L.sub.2 equal to 5.00 mm, a thread is formed comprising 5 peaks.

[0068] Preferably, the anchoring body 2 has, at its apical end E.sub.a, at least one tapping notch 6 made up of a longitudinal recess arranged from the apical end E.sub.a toward the cervical end E.sub.c of the anchoring body 2.

[0069] This second apical portion 8 is typically anchored in the cancellous bone part 4″ with a predefined depth 4′ of the jaw.

[0070] This second apical portion is further defined by a length L.sub.2′ that depends on the depth 4′ of the cancellous bone part 4″.

[0071] In this context, the length L.sub.1=L.sub.2+L.sub.2′ of the implant therefore depends on the one hand on the depth of the hard cortical bone 3′ of the jaw, and on the other hand on the depth 4′ of the cancellous bone part 4″ of the jaw.

[0072] Preferable, the second apical portion 8 has a cylindrical or conical shape with a taper converging towards apical end E.sub.a.

[0073] FIGS. 2 and 3 illustrate two different embodiments of the prosthetic assembly comprising: [0074] the implant 1 according to the invention; and [0075] a transgingival element 9 arranged to be connected to the coronal portion 3 of the anchoring body 2 and intended to support a prosthetic element.

[0076] The transgingival element 9 has a third length L.sub.3 equal to a gum thickness 9′″ of the implantation site. In general, this third length L.sub.3 is comprised between 3.0 mm and 4.00 mm.

[0077] In a first embodiment of the assembly according to the invention (FIG. 2), the assembly is an assembly of the “Tissue Level” type and comprises a transgingival element 9 assuming the form of a cervix 9′ protruding in the extension of the first coronal portion 3 of the anchoring body 2, along the longitudinal axis a.sub.L, in a direction opposite the apical end Ea of the anchoring body 2. In this way, the prosthesis cervix 9 and the anchoring body 2 form a single body.

[0078] In a second embodiment of the assembly according to the invention (FIGS. 3a to 3c), the assembly is an assembly of the “Bone Level” type where the transgingival element 9 is a pier 9″ connected, preferably removably, by a first connecting means 10 to the coronal portion 3 of the anchoring body 2.

[0079] The first connecting means 10 that connects the pier 9″ to the coronal portion 3 of the anchoring body 2 comprises a head body 10a protruding from the cervical end E.sub.c of the anchoring body 2 along said longitudinal axis a.sub.L, and having a beveled base shaped obliquely relative to a horizontal plane passing through the cervical end E.sub.c of the anchoring body 2. The head body 10a protrudes in a direction opposite the apical end E.sub.a of the anchoring body 3. The head body 10a is further arranged to nest in a first cavity 10b present in the pier 9″ through a cavity opening 10c of the pier (FIG. 3a). Preferably, the head body 10a assumes a conical shape and the first cavity 10b of the pier has a shape complementary to that of the head body 10a. Preferably, the taper of the head body 10a is greater than 0%, preferably comprised between 0.10% and 10%.

[0080] The taper C of a cone is defined in the context of the present invention as follows:

C (in %)=[(d−D′)/H]×100

where d corresponds to the basal diameter of the cone;
D′ corresponds to the cervical end diameter of the cone; and
H corresponds to the height of the cone.

[0081] Preferably, the head body 10a further comprises a second threaded cavity 10d arranged to accommodate the screw 10e, having a square body and a screw head, through an opening 10f of the head body 10a cavity 10d. The pier 9″ has an orifice 10g providing access to the cavity 10d of the head body 10a, such that the pier 9″ can be connected by bearing on the head body 10a via the screw head 10e, which, once screwed into the second cavity 10d of the head body 10a, compresses an apical surface part of the pillar 9″ on the head body (FIGS. 3b and 3c).

[0082] Alternatively (not shown), the pier 9″ is provided, on its base, with an apical element protruding from the base and arranged to be housed in a cavity formed in the coronal portion of the implant, through an opening defined on the cervical end of the implant.

[0083] FIG. 4 illustrates a third embodiment of the prosthetic assembly in a truncated view.

[0084] In this embodiment, the coronal portion 3 of the implant is defined by a side wall 11 that has a first vestibular face 11a and a second palatine face 11b, said palatine face 11b being in a position offset toward the cervical end E.sub.c relative to that of the vestibular face 11a along the longitudinal axis a.sub.L.

[0085] The palatine face is the face that is intended to be oriented toward the hard palate of the buccal cavity after the implant is placed.

[0086] The vestibular face is the face opposite the palatine face.

[0087] Furthermore, in this type of implant, the concavity of the coronal portion has a dual slope.

[0088] Furthermore, as illustrated in FIG. 4, advantageously, the head body 10a has at least one part characterized by a substantially polygonal transverse section (square 10′, pentagonal 10″, hexagonal 10′″), the cavity 10b of the pier having a polygonal shape complementary to that of the head body 10a. As shown by this figure, the cross-sections have scalloped polygonal cross-sections that have rounded edges assuming the form of bevels.

[0089] For all of the embodiments described above, an osteostimulating material can be arranged on the surface of the anchoring body, in particular on the surface of the coronal portion of the implant, so as to stimulate bone regrowth once the implant is placed on the implantation site. In this context, the space created between the peaks of the turns of the thread constitutes reservoirs of osteo-stimulating material.

Comparisons by Modeling a Traditional Dental Implant from the State of the Art with a Dental Implant According to the Invention

[0090] Finite element models (using the Samcef software, version 16, by the firm SAMTECH) were done on three-dimensional implant models (done using the CREO software, version 2, by the firm PTC) in order to compare, at the mechanical level, a traditional dental implant of the state of the art and an implant according to the invention, these two implants being made from a Ti6AL4V titanium alloy (with a Young's modulus set at 110 GPa for the calculation).

[0091] These models were done in order to determine and compare (1) the overall contact surfaces of the dental implant with the dense bone and the cancellous bone, (2) the compression stresses exerted on the one hand on the dense bone and on the other hand on the cancellous bone, and (3) the compression stresses exerted within the dental implant itself when a predetermined force is applied along the longitudinal axis (a.sub.L) of the dental implant at its cervical end (E.sub.c).

[0092] The force considered and applied in the context of these finite element models was set at 150 N, which corresponds to a mean molar mastication force (Guillaume Odin. Modélisation numérique de l'os mandibulaire appliquée à l'implantologie dentaire et maxillo-faciale [Digital modeling of the mandibular bone applied to dental and maxillofacial implantology]. Modeling and Simulation. Ecole Nationale Supérieure des Mines de Paris, 2008).

The characteristics of each of these dental implants are shown in table 1 below:

TABLE-US-00001 TABLE 1 Traditional dental Dental implant implant of according to the state of the art the invention Length (L.sub.1)  8.7 mm  8.7 mm Nominal diameter (d.sub.n) 4.27 mm 4.27 mm Outer diameter (d.sub.e)   4 mm   2 mm Ratio d.sub.n/d.sub.e 1.067 2.135

[0093] Furthermore, in order to perform these finite element models, the following Young's modulus values (elasticity modulus) were set for the different elements to be taken into account. The studies are provided in table 2 below:

TABLE-US-00002 TABLE 2 Young's modulus (MPa) Dense bone 3000* Cancellous bone  300* Dental implant 110,000 *Guillaume Odin. Modélisation numérique de l'os mandibulaire appliquée à l'implantologie dentaire et maxillo-faciale. Modeling and Simulation. Ecole Nationale Supérieure des Mines de Paris, 2008.
The obtained results are provided in table 3 below:

TABLE-US-00003 TABLE 3 Traditional dental Dental implant implant of according to the state of the art the invention Overall contact surface 132.3 mm.sup.2 150.3 mm.sup.2 (with the dense bone and cancellous bone) Compression stress  83.1 MPa 100.9 MPa exerted in the dense bone Compression stress  6.7 MPa  7.1 MPa exerted in the cancellous bone Compression stress  7.7 MPa  8.5 MPa exerted in the dental implant

[0094] As one can see, the overall contact surface of the dental implant according to the invention with the dense bone and the cancellous bone is increased. Furthermore, the compression stresses respectively exerted in the dense bone, the cancellous bone and the implant are also increased for an implant according to the invention, whose d.sub.n/d.sub.e ratio is comprised between 2 and 4 (d.sub.n/d.sub.e ratio=2.135 for the implant according to the invention considered in finite element models).

[0095] The compression increases of the dense and cancellous bone owing to a dental implant according to the invention are particularly advantageous because they make it possible to stimulate the bone tissue such that it reforms more quickly and that much better around the dental implant.

[0096] Of course, the present invention is in no way limited to the embodiments described above, and changes may be made thereto without going beyond the scope of the appended claims.