BIO-FUNCTIONALISED IMPLANT PART

Abstract

The present invention relates to a part (2) intended to be used in association with an implant (4) which is itself intended to be secured in a jaw, this part comprising, in series from its distal end (20) towards its proximal end (21), a distal portion (22) for securing in the implant, an intermediate portion (23) for attachment to the epithelial and/or connective tissue, and a proximal portion (24), this part also comprising at least two zones whose surfaces have a different structure, the structure of the surface of at least one of these two zones, located in said intermediate portion (23), said first zone being ordered and repetitive, adapted to the growth of the epithelial tissue and/or the connective tissue and having engravings forming corrugations with a depth of less than 0.5 microns.

Claims

1. A component (2, 3) intended to be used in association with a dental implant (4) which is itself intended to be fixed in a jaw, this component comprising successively, from its distal end (20, 30) and in the direction of its proximal end (21, 31), a distal portion (22, 32) for fixing in the implant, an intermediate portion (23, 33) for attachment to epithelial and/or connective tissues, and a proximal portion (24, 34), this component also comprising at least two zones whose surfaces have a different structure, the structure of the surface of at least one of these two zones, situated in said intermediate portion (23, 33), called the first zone, being ordered and repetitive, adapted to the growth of epithelial tissue and/or connective tissue, and having engravings which form ripples, of which the depth is less than 0.5 micron.

2. The component as claimed in claim 1, in which said first zone (230, 330) has a surface whose structure promotes the growth of epithelial tissue and also the attachment of the latter to the component, this first zone being situated inside the intermediate portion.

3. The component as claimed in claim 1, in which, in addition to this first zone, a second zone (231, 331) is provided whose surface has a structure different than that of the first zone (230, 330) and which promotes the growth of connective tissue and the attachment of the latter to the component, this second zone being situated in the intermediate portion of the component, between the distal portion (22, 32) and the first zone (230, 330) of the intermediate portion (23, 33).

4. The component as claimed in claim 3, in which, inside this second zone (231, 331), there is provided at least one other zone spaced apart from the first zone but having a surface whose structure is ordered and repetitive, different than that of the second zone, and promotes the rate of growth of the epithelial tissue and also the attachment of the latter to the component.

5. The component as claimed in claim 1, in which the structure of said first zone comprises micro-columns covered by the engravings which form ripples.

6. The component as claimed in claim 4, in which said other zone of the second zone comprises micro-columns covered by the engravings which form ripples.

7. The component as claimed in claim 1, comprising, in its intermediate portion, a third zone (232, 332) whose surface has a structure different than that of the first zone, designed to limit the attachment of dental plaque, this third zone being situated between said first zone (230, 330) and the proximal portion (24, 34).

8. The component as claimed in claim 7, in which the surface of the third zone is hydrophobic.

9. The component as claimed in claim 7, in which the structure of said third zone (232, 332) comprises nanopillars.

10. The component as claimed in claim 1, in the form of a prosthetic abutment (2) intended to be fixed in an implant, this abutment comprising, in its distal portion (22), a textured surface for ensuring the mechanical retention or sealing between the abutment and the implant.

11. The component as claimed in claim 1, in the form of a prosthetic abutment (2), the proximal portion (24) of which comprises a zone for fixing a prosthetic element, extending from the proximal end (21) of the abutment, this zone having a textured surface in order to improve the fixation between the abutment and the prosthetic element.

12. The component as claimed in claim 1, in the form of a healing screw (3).

13. The component as claimed in claim 1, the distal portion (22, 32) of which has a zone whose surface is engraved in order to ensure its traceability.

Description

[0051] The invention will be better understood and other aims, advantages and features thereof will emerge more clearly on reading the description which is given with reference to the appended drawings, in which:

[0052] FIG. 1 (already described) is a sectional view of the gum with a natural tooth and an implant anchored in the bone.

[0053] FIG. 2 is a perspective view of an example of a prosthetic abutment according to the invention.

[0054] FIG. 3 is a perspective and partially sectional view showing the abutment from FIG. 2 placed on an implant that is intended to be fixed in the gum.

[0055] FIG. 4 is an enlarged view of a detail from FIG. 2.

[0056] FIG. 5 is a photograph of a structure of the MC-LIPSS type.

[0057] FIG. 6 shows two diagrams illustrating the roughness profiles corresponding to an MC-LIPSS structure.

[0058] FIG. 7 is a photograph of a structure of the LIPSS type.

[0059] FIG. 8 shows two diagrams illustrating the roughness profiles corresponding to a structure of the LIPSS type.

[0060] FIG. 9 is a photograph of an NP type structure.

[0061] FIG. 10 shows two diagrams illustrating the roughness profiles corresponding to an NP structure.

[0062] FIG. 11 is a perspective view of an example of a healing screw according to the invention.

[0063] FIG. 12 is a view of the screw shown in FIG. 11 when placed in an implant fixed in the gum.

[0064] The features common to the various figures will be assigned the same references.

[0065] Reference is made first of all to FIG. 2, which illustrates an example of a prosthetic abutment according to the invention.

[0066] This abutment 2 comprises successively, from its distal end 20 and in the direction of its proximal end 21, a distal portion 22 for fixing in an implant, an intermediate portion 23, and a proximal portion 24.

[0067] The height of the distal portion 22 can be approximately 3 mm, that of the intermediate or sulcular portion 23 can be between 0.7 and 7 mm, and that of the proximal portion 24 can be between 4 and 12 mm.

[0068] This proximal portion 24 serves for fixing a prosthetic element on the abutment, while the intermediate portion 23 allows in particular the attachment of the abutment to the epithelial and connective tissues.

[0069] FIG. 3 illustrates an abutment 2 of the type in FIG. 2, when placed in an implant 4, which is shown here in section.

[0070] The implant 4 is provided with a first blind internal bore 40 comprising, on a distal end portion 42, an internal thread 41, and a frustoconical proximal end portion 43 for joining to the abutment 2.

[0071] The implant has a thread 44 on its outer face.

[0072] The distal portion 22 of the abutment comprises, starting from the distal end 20, a first part 220 and a second part 221.

[0073] In a known manner, the second part 221 is frustoconical and is designed to cooperate by friction with the proximal end portion 43 of the implant when the junction between the abutment and the implant is complete.

[0074] Furthermore, the first part 220 comprises bevels and is designed to cooperate with a zone of corresponding shape of the implant 4, situated between the internal thread 41 and the frustoconical end portion 43.

[0075] Finally, the abutment 2 is fixed in the implant by means of a screw 5 which penetrates into a bore of the abutment in order to be screwed into the internal thread 41 of the implant, by virtue of the thread present on a distal portion of the screw.

[0076] In the context of the invention, the structure of the surface of the intermediate portion 23 is defined so as to promote the attachment of the abutment to the epithelial and connective tissues.

[0077] Reference is now made to FIG. 4, which illustrates in more detail the intermediate portion 23 of the abutment 2.

[0078] In practice, this intermediate portion can be broken down into three zones: [0079] a first zone 230, the surface of which has a structure intended to promote the growth of epithelial tissue and the attachment of the latter to the abutment 2, this first zone 230 being flanked by [0080] a second zone 231 which extends between the first zone and the distal portion 22 of the abutment, this second zone having a surface whose structure promotes the growth of connective tissue, with fibers oriented substantially radially, and also the attachment of said tissue to the abutment 2, and by [0081] a third zone 232 which extends between this first zone and the proximal portion 24 of the abutment, the surface of this third zone being hydrophobic, so as to limit the attachment of dental plaque.

[0082] It should be noted here that this intermediate portion 23 does not necessarily comprise three zones whose surface has a structure with a particular function, as stated above.

[0083] In practice, however, there should be at least a first zone whose surface has a structure promoting the growth of epithelial tissue or a second zone whose surface has a structure promoting the growth of connective tissue with fibers oriented substantially radially.

[0084] If only one of these zones were to be present on the abutment, it is the first zone that would preferably be provided, since it permits the creation of a biological seal around the abutment and therefore makes it possible to create a first barrier to bacteria as close as possible to their point of entry into the gum.

[0085] This first barrier results in particular from the fact that the epithelial cells attach themselves to the abutment.

[0086] Of course, even greater efficacy is obtained when the first and second zones are present on the abutment. Indeed, the presence of the second zone makes it possible to obtain a connective tissue whose structure is similar to that which exists with a natural tooth, and which then constitutes an effective support structure for epithelial attachment.

[0087] In this second zone, the fibers of the connective tissue do not wind around the abutment but extend substantially perpendicularly or radially with respect to the abutment.

[0088] The abutment according to the invention thus makes it possible to re-establish a cellular environment very similar to the one existing around a natural tooth.

[0089] Finally, the third zone 232, when present, contributes further to the efficacy of the biological seal thus created, by limiting the attachment of dental plaque.

[0090] With reference to FIGS. 7 to 10, examples of surface structures will now be explained which make it possible to fulfill the functions that have just been described.

[0091] Generally, these structures are obtained by means of a femtosecond laser, that is to say a laser producing ultrashort pulses whose duration is between a few femtoseconds and a few hundred femtoseconds.

[0092] They then undergo a cleaning operation.

[0093] A laser of this type makes it possible to obtain engravings whose depth is of the order of a hundredth of a micron and which are ordered, that is to say non-random, and repetitive, that is to say are formed of a pattern repeated on this surface and are reproducible. It is thus possible, with certainty, to confer the desired function on each surface, by suitably parameterizing the laser.

[0094] Moreover, the laser treatment of the abutment surface, carried out with air, oxidizes this surface. This is in particular due to the temperature level reached at the surface during this treatment.

[0095] Thus, when the abutment is made of titanium or of a titanium alloy, the laser treatment creates a layer of titanium oxide which is a biocompatible surface and is more resistant to corrosion than the starting constituent material. Moreover, this oxide layer promotes mineralization.

[0096] Examples of structures for the surfaces of each of the three zones 230 to 232 will now be described.

[0097] At the level of the first zone 230, provision may be made to texturize the abutment by a femtosecond laser so as to obtain micro-columns that are covered with periodic surface structures forming ripples (or LIPSS, that is to say Laser-Induced Periodic Surface Structures). This particular structure is designated by the term MC-LIPSS.

[0098] An example of an MC-LIPSS surface structure is illustrated in FIG. 5. Thus, this surface comprises micro-columns whose cross section is substantially elliptical and which are covered with structures forming ripples (LIPSS structures) whose periodicity is of the same order of magnitude as the radiation wavelength of the laser or of a few hundred nanometers. Thus, two adjacent ripples are spaced apart from each other by a distance of between 500 nm and 1000 nm.

[0099] FIG. 6 shows for two types of titanium, a commercially pure titanium (cp Ti) and a titanium alloy (of the type Ti6Al4V), two graphs illustrating the variation in the height of the roughnesses of the textured surface (in microns), according to a standardized measurement of the linear surface profile, as a function of the length of the sample (in microns).

[0100] The roughness parameters of such a surface were measured. It will be noted that the parameter R.sub.a gives the arithmetic mean roughness of the profile, while the parameter R.sub.z gives the maximum roughness of the profile.

[0101] The parameter R.sub.a (expressed in microns) is of the order of 0.8 micron for a titanium substrate and of the order of 0.7 micron for a Ti6Al4V substrate.

[0102] Furthermore, the parameter R.sub.z (expressed in microns) is of the order of 5.3 for a titanium substrate and of the order of 5.4 for a Ti6Al4V support.

[0103] In practice, a texturing with micro-columns is obtained by treating the surface using a femtosecond laser. Under the effect of the femtosecond laser, firstly, the periodic surface structures appear in the form of substantially parallel ripples (LIPSS) and, by virtue of the pulse energy of the femtosecond laser, the micro-columns appear in a second step. They are thus covered with LIPSS structures.

[0104] Preferably, the diameter of each micro-column at its base is between 600 nm and 800 nm.

[0105] This structure can extend uniformly over the entire surface of the first zone.

[0106] However, the invention is not limited to this embodiment.

[0107] Thus, on the surface of the first zone, a specific design can be produced, consisting of geometric figures distributed in the form of a matrix, these figures possibly being a circle, a square or a triangle, for example. In this matrix, two adjacent figures are typically spaced apart by a distance of between 25 microns and 75 microns. These figures define the space in which the micro-columns are located.

[0108] In practice, these non-random geometric figures are obtained by concentrating the pulse energy of the femtosecond laser in specific zones that define these geometric shapes.

[0109] The micro-columns covered with LIPSS structures are obtained in these zones, while the rest of the surface is only covered with LIPSS structures.

[0110] The entire surface is therefore covered with structures forming ripples of the LIPSS type.

[0111] Thus, these ripples cover the entire surface of the first zone, whether or not the latter comprises micro-columns over its entire surface.

[0112] Preferably, two adjacent ripples are spaced apart from each other by a distance of between 500 nm and 1000 nm and have a height of between 100 nm and 500 nm.

[0113] In a variant, provision can be made to adjust the femtosecond laser in order to concentrate its pulse energy and thus locally vaporize the surface of the first zone. The MC-LIPSS structure is generated around this vaporization, over the entire surface.

[0114] When the MC-LIPSS structure is produced according to a matrix, the surface of the first zone, which is neither vaporized nor covered with an MC-LIPSS structure, is covered with LIPSS structures.

[0115] This type of structure has been found to promote the differentiation and growth of epithelial tissue, which is why it is provided in the first zone 230 of the intermediate portion 23.

[0116] As regards now the second zone 231, provision can be made to texturize its surface so that it has structure of the LIPSS type (Laser-Induced Periodic Surface Structures), that is to say a periodic surface structure obtained by laser treatment.

[0117] As has been indicated above, these structures consist of substantially parallel ripples.

[0118] A structure of this type is shown in FIG. 7.

[0119] FIG. 8 is a view similar to FIG. 6 and shows two graphs, the first corresponding to pure titanium and the second to a titanium alloy of the Ti6Al4V type, illustrating the variation in the height of the roughnesses of the surface (in microns) according to a standardized measurement of the linear surface profile, as a function of the length (in microns) of the sample.

[0120] As before, the roughness parameters R.sub.a and R.sub.z can be calculated for this type of structure. It is thus possible to measure that R.sub.a is substantially equal to 0.3 micron for pure titanium and for an alloy of the Ti6Al4V type, and that R.sub.z is equal to approximately 1.5 microns for pure titanium and 1.4 microns for an alloy of the Ti6Al4V type.

[0121] In the context of the invention, a structure of the LIPSS type will be used whose ripples are spaced apart by approximately 500 nm and, more generally, whose periodicity is between 500 nm and 1000 nm, these ripples having a height of between 100 nm and 500 nm.

[0122] It has been found that a structure of this type makes it possible to promote the growth of connective tissue with fibers oriented substantially radially.

[0123] As has been explained above, this second zone 231 is preferably provided in addition to the first zone 230, so as to constitute an effective support for the epithelial attachment, the formation of which is promoted by the particular texturing of the first zone 230. However, this second zone 231 could be provided on its own.

[0124] In this regard, it may be advantageous to provide, inside this second zone 231, a surface part which has a different texturing and promotes the formation of epithelial tissue.

[0125] Thus, this surface part will be able to have, for example in an annular fashion, a texturing identical to that of the first zone 230 or, in any event, a texturing that fulfills the same function.

[0126] The presence of this other differentiated zone inside the second zone makes it possible to create, inside the latter, a point of attachment of the epithelial tissue, under the epithelial attachment itself, which creates an additional barrier against the introduction of bacteria.

[0127] It should be emphasized that the surface structures described with reference to FIGS. 7 to 10 are only examples of implementation of the invention and that the latter is not limited to these examples.

[0128] As regards now the third zone 232 of the intermediate portion 23, it will be possible to provide on its surface a texturing of the nanopillar type (NP).

[0129] This structure is illustrated in FIG. 9.

[0130] Furthermore, FIG. 10, like FIGS. 6 and 8 described above, shows two graphs illustrating the roughness profiles of such texturing, on the one hand for pure titanium and on the other hand for a titanium alloy of the Ti6Al4V type.

[0131] Each of these graphs gives the height of the roughnesses (in microns) according to a standardized measurement of the linear surface profile, as a function of the length of the sample (in microns).

[0132] The roughness parameters R.sub.a and R.sub.z were also calculated for this type of texturing. Thus, R.sub.a is substantially equal to 0.3 micron for pure titanium and an alloy of the Ti6Al4V type, while R.sub.z is equal to approximately 1.6 microns for a pure titanium substrate and 1.3 microns for a substrate made of titanium alloy of the Ti6Al4V type.

[0133] A nanopillar structure of this type is obtained by means of a femtosecond laser and in two steps.

[0134] In a first step, the surface of the substrate is treated to obtain periodic surface structures (of the LIPSS type) which are in the form of substantially parallel ripples.

[0135] In this first step, the parameters of the laser are set so that they generate 192 pulses, with a fluence of 0.3 J/cm.sup.2. In this first step, the polarization of the laser beam is straight.

[0136] The second step of the surface treatment is again carried out by a femtosecond laser, but with a lower fluence and smaller number of pulses. Thus, this second step can be carried out with a laser configured to generate 47 pulses, with a fluence of 0.10 J/cm.sup.2. In this second step, the polarization of the laser beam is still straight, but its direction is rotated through 90° with respect to the direction of the polarization used in the first step of the surface treatment.

[0137] Thus, the ripples formed during the first step of the treatment are partially destroyed by the second step of the treatment, so as to form these nanopillars.

[0138] This structure can extend uniformly over the entire surface of the second zone.

[0139] However, the invention is not limited to this embodiment. Thus, the surface of the second zone can comprise a matrix of pads of substantially square shape, the nanopillar structure being produced on the surface of each pad.

[0140] In this matrix, the side of the pads is between 20 microns and 45 microns, and two adjacent pads are spaced apart by a distance of between 20 microns and 35 microns.

[0141] It will be noted that this surface structure makes it possible to limit the formation of biofilm with respect in particular to a polished surface.

[0142] That is why this type of texturing is advantageously used in the third zone 232.

[0143] However, the invention is not limited to this type of texturing.

[0144] In particular, it has been observed that a textured surface of the LIPSS type also has this particular feature of avoiding the formation of biofilm.

[0145] Finally, and in a non-limiting manner, any type of hydrophobic surface can be used for this third zone 232, in order to avoid the formation of biofilm.

[0146] It will thus be understood that this third zone makes it possible to reinforce the effects of the first zone and/or of the second zone by limiting the presence of bacteria above these two zones. It therefore reinforces the biological barrier function already fulfilled by one or the other of these two zones.

[0147] In addition to the particular structures that are given to the surface of the abutment in its intermediate portion, the invention also proposes that the other surfaces of the abutment be provided with particular structures in order to give them enhanced functions.

[0148] Reference is again made to FIG. 2, which illustrates not only the intermediate portion 23 but also the distal portion and the proximal portion of the abutment.

[0149] As has been indicated above, the distal portion 22 is the portion of the abutment that will serve for fixing it in the implant.

[0150] Preferably, the structure of the surface of this distal portion 22 is chosen so as to improve the sealing of the connection between the abutment 2 and the implant.

[0151] This structure can also be obtained by the action of a femtosecond laser. It may in particular be a structure having a micrometric grip aimed at increasing the mechanical bond retention (for example conical) between the abutment and the implant and at improving the sealing at the interface between the two components.

[0152] Improving the sealing of the connection between the abutment and the implant also makes it possible to avoid contamination by pathogenic bacteria present in the mouth, which can lead to bone loss.

[0153] In this distal part, and in particular in the most distal first part 220, an engraving of the abutment can be provided, here once again by means of a nanosecond or femtosecond laser.

[0154] This engraving can consist of a 2D code, of the data Matrix type, permitting the unique identification of the abutment.

[0155] By virtue of this engraving, it is then possible to trace the abutment in an original and unique manner, after it has been fixed in the implant.

[0156] Furthermore, the proximal portion 24 of the abutment is intended for fixing a prosthesis.

[0157] Here again, provision can be made for the surface of this proximal portion to have a particular structure, in order to improve the attachment of the prosthesis to the abutment.

[0158] By way of example, this structure can be of greater roughness than the raw machined structure, in order to increase the retention of the sealing or bonding of the prosthesis on the abutment.

[0159] It will thus be understood that the invention proposes giving the surface of each part of the abutment a specific structure, so as to confer on it a particular function or to improve the function already fulfilled.

[0160] These different parts of the abutment are therefore no longer passive but on the contrary active in relation to their environment, whether or not a living environment.

[0161] Reference will now be made to FIGS. 11 and 12 which illustrate a healing screw, in order to show how the invention can be adapted to such a screw.

[0162] On such a healing screw 3, three portions can also be defined from its distal end 30 to its proximal end 31. Thus, the screw 3 comprises a distal portion 32 for fixing in the implant 4, this portion comprising a thread 35.

[0163] This distal portion 32 comprises, for example, a conical zone, the height of which is approximately 2 mm, and a thread, the height of which is between 1 and 3 mm, for a diameter of between 1.2 and 2 mm.

[0164] In the direction of its proximal end, there extends an intermediate portion 33, the height of which is between 0.7 and 7 mm and which is in particular equal to 3 mm. It is continued by a proximal portion 34, the height of which is between 1 and 5 mm and which is in particular equal to 3 mm. The latter corresponds to the part of the screw situated partially outside the gum when the healing screw is screwed into the implant, the latter itself being fixed in the jaw of a patient.

[0165] Within the intermediate portion 33, three zones can be defined: a first zone 330, framed by a second zone 331 and a third zone 332. The second zone 331 extends between the first zone 330 and the distal portion 32 of the screw, while the third zone extends between the first zone and the proximal portion 34 of the screw.

[0166] As with an abutment according to the invention, the surface of each of these zones is chosen to have a particular function.

[0167] Thus, the structure of the surface of the first zone 330 will be chosen to promote the growth of epithelial tissue. As has been described above, this structure can in particular be of the MC-LIPSS type. This structure has already been described for an abutment and will not be described again in detail.

[0168] Likewise, the structure of the surface of the second zone 331 will be chosen so as to promote the growth of connective tissue, with fibers oriented substantially radially.

[0169] This structure can in particular be of the LIPSS type, as has been described above for an abutment.

[0170] Finally, the structure of the surface of the third zone 332 will be chosen such that this surface is hydrophobic, and reference will again be made here to the examples given above for an abutment according to the invention.

[0171] It is preferably the first zone 330 that has a functionalized surface, so as to create a barrier to bacteria that is farthest from the bone.

[0172] This barrier function is of course reinforced when the second zone 331 is itself functionalized in accordance with the invention.

[0173] Finally, the third zone 332, when it is hydrophobic, makes it possible to avoid the attachment of dental plaque, and this further reinforces the barrier function provided by the first zone 330 and/or the second zone 331. The function of this third zone 332 is therefore complementary to that of the first zone and/or of the second zone.

[0174] As has been described for the abutment 2, annular parts can be provided inside the second zone 331, the surface of said annular parts having a structure that has the same function as the first zone, that is to say promoting the growth of epithelial tissue. This makes it possible to create, inside the second zone, epithelial attachments in addition to the one already created at the level of the first zone 330.

[0175] FIG. 12 shows the screw 3 in the implant 4, which is itself fixed in the bone 12.

[0176] Finally, the invention is not limited to the examples that have just been described, and other variants could be envisioned.

[0177] Thus, the constituent materials of an abutment or of a healing screw according to the invention are typically based on titanium, whether commercially pure titanium or a titanium alloy. However, other biocompatible materials can be considered, such as other metal alloys (titanium-niobium, titanium-zirconium, cobalt-chromium), ceramics (zirconia) or plastics (PEEK, polyethylene).