WO2006108951A1

WO2006108951A1 - Screwed implants

Info

Publication number: WO2006108951A1
Application number: PCT/FR2006/000779
Authority: WO
Inventors: Guy Peltier; Patrick Peltier
Original assignee: PARIS IMPLANTS (Société à Responsabilité Limitée)
Priority date: 2005-04-12
Filing date: 2006-04-07
Publication date: 2006-10-19
Also published as: EP1868523A1; BRPI0609070A2; FR2884138A1; FR2884138B1

Abstract

The invention concerns a single-unit dental implant having one implant body forming part (1) and one pillar forming part (2), said implant body being substantially symmetrically rotating about a longitudinal axis (L) and comprising a cylindrical threaded central part (3) extending through a substantially conical self-tapping end part (4) tapering away from the part (3) and provided on its periphery with longitudinal cutting notches (5), and at its other end, the cylindrical part (3) extends through a truncated smooth shoulder (6) flaring away from the cylindrical part (3). A polygonal pit (9) centered on the axis (L) passes through the pillar (2a) and can co-operate with a screwing wedge.

Description

VISE IMPLANTS

The present invention relates to an improvement to dental implants.

A dental implant usually comprises an implant body, generally externally threaded and internally threaded, intended to be implanted in the bone tissue of the mandible or maxillary and, a so-called abutment or abutment piece capable of being transfixed. on the body of the implant, so as to rise above the implant, to receive a dental prosthesis. So that the prosthesis is properly oriented, with good parallelism with respect to the natural teeth, it is necessary to be able to orient, around the axis of the body of the implant, the abutment or abutment, and then fix it. It is the same for the inclination, which can be obtained either by a variable inclination means or by a set of pillars pre-inclined at different angles. Two-part constructible implants are, for example, described in US-A-5,947,733, DOS 27,435,035, GB-A-2,252,501, EP-A-0 337,759, EP 0 139 052, JP-A-08. 252269.

WO2005 / 020839 discloses straight screw-on metal implants comprising a pier and a threaded implant body and provided with cutting notches. The pillar and the body are separated by a thinned area for forcibly tilting the pillar relative to the body to give the desired angle.

For an angular adjustment in rotation around the axis of the body of the implant, it is also known to use indexing means, such as a polygonal assembly, for example with 6 or even 12 faces, or an assembly serrated implant face and abutment, for example from 24 to 36 teeth. These known indexing means create local decreases in thickness and sometimes pose difficulties that may be detrimental to the strength of the assembly, given the very great efforts to which the implant can be subjected. For these reasons, one-piece implants have been developed and proposed to be impacted in an orifice previously made for this purpose in the mandibular or maxillary bone: US-A 3,950,850, US-A-4,474,556, FR-A-2,759,283.

The most successful evolution of the monobloc implants is undeniably the solution proposed in WO-A-0224098, which proposes a set of implants comprising several single-piece implants having an implant body portion and a pillar portion, the various implants of the implant. play having different angles between the axis of the implant body and the axis of the abutment, with circular conical implant bodies having a taper between 3 and 6 °, in particular 3, the implant bodies being arranged to be able to being fixed in the mandibular or maxillary bone by impaction and being provided with anti-raising means comprising the anti-lift effect due to the taper and anti-rotation means capable of cooperating with the adjacent bone to maintain the implant in his position. These implants can be made of molded zirconia. They are very quick to put in place and osteocoaptation is faster than usual.

Nevertheless, it remains true that, in the field of dental implantology, a certain proportion of practitioners still favor implants to be screwed into the mandibular or maxillary bone, despite the disadvantages inherent in piercing the bone with the help of a special tool. Thus, since it is not possible to ensure a precise drilling angle, the implants used generally have a device for orienting the abutment, either deformable, or comprising moving parts which are as many zones of weakness and which imply the existence of joint plans sensitive to bacterial development. In addition, during the installation, it is necessary to eliminate the bone debris present in the cavity made to receive the body of implants, which could oppose the screwing of this body.

The present invention has set itself the objective of proposing new screw-in implants, which solve the disadvantages of screw-in implants of the prior art, namely which benefit from easier and faster placement, rapid osteocoaptation. , and which do not present the zones of weakening and bacterial development that are known in implants screwed before. In addition, these implants must necessarily be placed in both the mandibular bone and maxillary, in an open area as between two teeth.

The invention thus relates to a one-piece dental implant having an implant body portion arranged to be immobilized in the mandibular or maxillary bone and a pillar portion arranged to be able to protrude from the bone to receive an external dental device. The implant body is screwable, substantially symmetrical in revolution about a longitudinal axis L and has a threaded central cylindrical portion, preferably substantially along its entire length. It continues with a substantially tapered self-tapping end portion tapering away from the cylindrical portion and provided on its periphery longitudinal cutting notches, extending over all or part of the length of this portion. At its other end, the cylindrical central portion continues with a frustoconical smooth shoulder flaring away from the cylindrical portion. Preferably, the cylindrical portion is threaded over its entire length.

According to one characteristic, the dental implant is made of zirconia by molding and sintering, or by molding, sintering and grinding.

An implant thus shaped can advantageously be put in place in a borehole previously made in the mandibular or maxillary bone, this bore preferably being of a diameter slightly less than the overall diameter of the cylindrical portion. The drilling . allows to guide the implant during its screwing, as and when the self-tapping part is a path. Thanks to self-tapping, bone debris does not have to be evacuated, but instead can be distributed in the space created by the thread of the cylindrical part of the body, which promotes bone regrowth and osteocoaptation of the implant (Osteocoaptation means osteointegration of a foreign body, in this case the implant body). In addition, the notches have an anti-rotatory effect, ensuring a maintenance of the implant before and after osteocoaptation. The shoulder is intended to come into contact with the cortical and according to an advantageous arrangement of the invention, the drilling is done in such a way that the cortex has a bore substantially conforming to the shape of the shoulder while being slightly smaller in diameter, to ensure a perfect seal against the joint plane between cortical and shoulder.

The cutting notches of the self-tapping part and in particular their cutting edges are substantially parallel to the slope of the cone in which the self-tapping part fits. They are preferably regularly distributed around the periphery of the zone. They are shaped so as to present each face to the bone during screwing, an acute sharp cutting edge. The length of the notches should be sufficient to ensure complete penetration of the implant body into the bone. This length is preferably between 1/4 and 1/2, better between 1/4 and 1/3 of the length of the cylindrical portion. In a preferred embodiment, the longitudinal edge is discontinuous and therefore has aligned teeth each having a cutting edge facing the bone to be cut. The length of the teeth may be variable and in particular the length decreases from the free end of the implant body to the cylindrical portion, and preferably to the seal between the frustoconical portion and the cylindrical portion, the teeth have substantially the size of the thread of the the cylindrical part with which they eventually merge to form a continuity between the indentation and the net. Similarly, it is preferable that the depth of the teeth increases in the same direction, until reaching the depth of the net. According to one characteristic, the notches extend over the first turn or a few first turns of the thread of the cylindrical portion.

According to an advantageous modality, the notches are such as obtained by grinding or machining substantially rectilinear notches in the conical part originally having a thread or a grooving, for example a thread coming from a single piece with the threading of the cylindrical portion of the implant body. If the notches can be made by machining, it should be specified that they can also be obtained by molding with the rest of the implant, using a mold presenting the necessary indentations. Depending on the number and arrangement of the notches, and the requirements related to demolding, it can be expected to form some notches by molding and others by machining.

The notches are preferably substantially parallel to the slope of the cone in which the frustoconical self-tapping part fits. Alternatively they may extend in a slightly helical shape.

The self-tapping end portion is substantially in a truncated cone of 10 to 30 °, preferably 16 to 24 °, e.g. 20 ° (these values correspond to the angle at the top of the cone). The longer the implant body, the longer the frustoconical self-tapping part is long and the angle of the cone is small. It may comprise from 4 to 12 cutting notches, preferably from 6 to 10.

The smooth shoulder is preferably in a cone of revolution of 2 ° to 6 °, preferably 3 ° to 5 °, more preferably 4 °. This shoulder is intended to be applied in contact with the cortical bone to seal insertion and may ^{advantageously} have a length of several millimeters, in particular 1 to 3 mm, preferably from 2 to 2.5 mm. The practitioner will have previously made a suitable conical drilling in the bone, from the cortex, it being specified that the angle of conicity retained is preferably the same, which allows the shoulder to come into perfect contact with the cortical and, preferably, slightly expand the bone when the implant is in place. This faculty is also used by the practitioner to ensure a perfect orientation of the pillar, as will be explained later. It is thus preferable that the diameter of the hole made, with the same conicity, be slightly smaller (generally smaller by a few hundredths of a millimeter) than the outer surface of the shoulder, to ensure that the joint between bone and shoulder. In place, the shoulder is arranged to extend into the bone from the cortex and ensures a perfect seal avoiding bacterial growth. At its opposite end to the cylindrical portion, the shoulder carries the pillar portion. According to an advantageous embodiment, it is continued by a smooth conical widening, possibly curved, whose vertex carries the pillar proper and forms with it the part forming pillar. This so-called gingival enlargement corresponds to the portion of the implant passing through or located at the level of the gum, and constitutes an enlarged zone of high mechanical strength. This smooth portion preferably has a height of 1 to 3 mm, preferably 2 to 2.5 mm.

The pillar can have any usual form. For a zirconia implant, it is convenient to make a simple frustoconical shaped abutment whose base is substantially centered on the gingival enlargement and has a smaller diameter than the latter. The frustoconical abutment can for example be part of a cone of 8 to 12 °.

The implants according to the invention being monoblock implants by definition without means for orienting or inclining the abutment, several embodiments are provided.

A first embodiment corresponds to a straight or rectilinear implant in which the axis of the abutment coincides with the longitudinal axis L of the implant body.

A second embodiment corresponds to inclined implants in which the axis of the abutment is inclined with respect to the longitudinal axis L of the implant body. According to the invention, a range of inclination ranging from 0 ° to

30 ° with respect to the axis of the body. Preferably, the inclined implants are at an angle varying from 1 to 30 °, for example 5, 9, 10, 12, 15, 18, 20, 24 or 25 °.

According to an advantageous characteristic of the invention, a well having on at least a portion of its length a polygonal section, extends in or passes through the pillar portion being centered on the longitudinal axis L of the implant body. This feature makes it possible to use a tool of complementary shape, to ensure the screwing of the implant even in a difficult access area as in the case of an inclined implant to be disposed between two teeth. The well is preferably polygonal throughout its length.

Preferably, for reasons of solidity in particular, the end of the well is located in the gingival enlargement which connects the implant body to the pillar, present in this area a polygonal section (eg about 1 to 3 mm in length), and does not extend beyond in the part of the implant that is integrated with the bone. Preferably, a tool shaped to fit closely in this extreme zone is used to essentially transmit the rotational force at this region of greater mechanical strength.

In order to facilitate its implementation, especially when it is produced by molding or compression in the presence of a removable insert giving it its shape, the well may advantageously have a section that decreases slightly toward the bottom.

Alternatively or in addition to the well, the pillar may include flats on its outer periphery, which allow the screwing by means of a suitable key, and also contribute to the anti-rotation of the prosthesis which will be mounted on the pillar. According to another embodiment, the implant comprises a ball pillar, which carries a spherical end and a constriction between this end and the gingival piece joining the pillar to the implant body. This type of abutment is generally used in duplicate to mount a dental appliance replacing several teeth in one fell swoop, and access problems being less, the polygonal well may be omitted. The flats are however provided on the perimeter of the gingival piece.

According to the preferred embodiment of the invention, the one-piece implant is made of zirconia from zirconium oxide. It can be made of zirconia by molding and sintering, or by molding, sintering and rectification (eg machining with a diamond grinding wheel) or by grinding (eg machining with a diamond grinding wheel) of a preform, preferably cylindrical, obtained by compression. The molding is under pressure. It is preferably zirconia dental or surgical grade.

In the preferred embodiment of the invention, the zirconia implant is made by high-pressure molding and then sintering at high temperature (generally between 1400 and 1500 ⁰ C). The size of the molds takes into account the shrinkage during sintering. According to one embodiment, the implant has eight notches. According to one characteristic, six of the notches come from molding and two are made by grinding.

In another embodiment, the implant has six or seven notches. According to one characteristic, these six or seven of the notches come from molding. According to another characteristic, one or two of these notches are made by grinding, the others are molded.

The notches obtained from molding are advantageously sharp and do not need to be ground. If certain notches are made by grinding, which can be done in particular when the total number of notches would not allow a correct demolding if all came from molding, these rectified notches may possibly not have the cutting character of the notches molded, but serve nevertheless to have an optimal even distribution of notches around the periphery and to contribute to the formation of the space in which is housed at least a portion of the bone debris during the screwing of the implant.

It can be seen that the zirconia implants according to the invention induce very rapid consolidation and osteocaptation. The presence of the self-tapping part also allows to leave in situ bone debris resulting from tapping, these debris being placed in the threads of the cylindrical portion and between the notches, these bone debris then promoting bone regrowth. The self-tapping portion also has an anti-rotation effect. The practitioner will be able to assemble the dental prosthesis more quickly on the abutment since the implant, more quickly integrated, will allow an earlier loading. The implants have a very high strength, combined with excellent osteocoaptation and minimal trauma to the pose. Zirconia implants avoid electrically conductive contacts with the dental nerve and allow a better aesthetic appearance, not being visible under the wall of the dental prosthesis which is often thin and translucent. Alternatively, it may be made of titanium, or any other biocompatible surgically acceptable material.

Due to the absence of hollow parts in the implant body, the geometry of the polygonal well extending into the enlarged region and the monobloc continuity between the implant body and the pillar body, it is perfectly conceivable the great strength of the monobloc assembly.

These implants can also be miniaturized, for example to use several implants to support a replacement prosthesis of a single tooth.

The present invention also relates to a set of dental implants comprising several one-piece implants according to the invention, having angles of inclination axis of the body / axis of the pillar different. Preferably, the angles between the aforementioned axes of the implants of the game range from 0 ° to 30 °.

By way of example, one set may have two implants with 0 and 12 ° angles, or 0 and 15 °, three implants of 0, 9 and 18 °, or 0, 10 and 15 °, four 0, 9, 12 and 18 °, or 0, 10, 15, 20 °. Of course other variations of angles are possible, for example 10 ° in 10 °, or values between 5 and 10 °, or combinations of these values, for example 5 in 5 ° for the weakest angles and from 10 to 10 ° for larger angles.

The subject of the invention is also a drill specially designed for laying implants according to the invention, of the piercer-reamer type, comprising a special cut allowing a clean and precise drilling with a low rotational speed, and allows to obtain the realization of a drilling without any vibration, guaranteeing the good geometry and, the good surface state in the cortex of the bone. The drill extends along a longitudinal axis L, and comprises in order, an active longitudinal portion having a thread (for threading) for drilling inside a jaw bone, a stop and a longitudinal portion of link or pin for connecting the drill to means for driving in rotation about the axis L. The active part is substantially symmetrical about the L axis and is stepped, comprising two distinct sections of increasing diameters of the free end of the active part to the spindle. More specifically, the active part comprises from its free end towards the spindle a first cylindrical section and a second frustoconical section.

The first section is cylindrical and its outside diameter is adapted to the diameter of the cylindrical portion of the implant body, and is preferably chosen so that its diameter is that of the bottom of the thread of the cylindrical portion. The second section fits into a cone identical to that of the frustoconical smooth shoulder of the implant body, and can therefore be between 2 and 6 °, preferably between 3 and 5 °, ideally 4 °; the diameter is as indicated above, preferably less than a few hundredths of a millimeter from that of the shoulder.

The drill advantageously has from 3 to 5 threads, preferably 4 threads extending helically around the axis L from the free end of the first section, and up to substantially the end of the second section. Preferably, each net has a cutting edge or lip oriented towards the bone to be cut in the direction of rotation of the drill. Other features and advantages will appear on reading the detailed description of an example of a 4-thread drill in the shape of a Maltese cross.

The recesses separating the threads allow the lips to cut and retain the bone chips. This bone paste, mixed with blood, may be retained in these recesses and may be, in part, reintroduced into the borehole to accelerate osteocoaptation.

Finally, the subject of the invention is also a process for manufacturing zirconia monoblock implants according to the invention, in which the implant is made from zirconium oxide by molding and sintering, or by molding, sintering and grinding. (eg diamond grinding). Sintering is carried out at high temperature (generally between 1400 and 1500 ⁰ C). The molding is under pressure. It is preferably zirconia dental or surgical grade. In the preferred embodiment of the invention, the zirconia implant is made by high-pressure molding, followed by high-temperature sintering. The size of the molds takes into account the shrinkage during sintering.

According to one embodiment, the molding of implant sets is performed. The subject of the invention is therefore a method and a device for molding sets of implants according to the invention, in zirconia. Simultaneous molding of at least two types of implants (for example different inclinations or different diameters), for example a set of various implants, as will be described later, using a mold multiple. After molding, sintering and possibly rectification are carried out.

Other advantages and characteristics of the invention will appear on reading the following description, given by way of non-limiting example, and with reference to the appended drawing, in which: FIG. 1 represents an elevational view of an implant FIG. 2 represents an elevational view of an inclined implant according to the invention, FIGS. 3 and 4 each represent a sectional view of the abutment, in a plane perpendicular to its axis, of the implant. of Figure 1, respectively 2; FIG. 5 represents a sectional view of the self-tapping part of the implant of FIG. 2, FIGS. 6 and 7 represent elevational views of implants with a ball-ended abutment, FIG. 8 represents an elevational view of the implant of FIG. a drill for the placement of the implants according to the invention, FIG. 9 represents an end view of this drill, FIG. 10 represents a schematic view of a device for molding a set of implants in zirconia according to FIG. invention. The one-piece implants shown in FIGS. 1 and 2 comprise an implant body portion 1 formed of a cylindrical portion 3 which has a shape of a revolution cylinder and which is threaded substantially over its entire length (the threading is simply shown in FIG. 1 while Figure 2 shows it in more detail). This cylindrical portion 3 continues with a substantially tapered self-tapping end portion 4 tapering away from the portion 3 along a slope of 10 °. This end portion is provided on its periphery with eight notches cut 5 staple extending in a manner longitudinally substantially in the axial direction of the implant body 1 and parallel to the slope of the cone. These notches continue on the first two thread turns of the cylindrical portion 3.

FIG. 5 shows a cross-sectional representation of this self-tapping end portion 4, the notches of which are inclined and oriented in the screwing direction and have a cutting edge 4a and delimit spaces 4b capable of receiving debris. 'bone.

Given the number of notches and the general shape of this part 4, it can be specified that, to facilitate demolding, this part 4 can come from molding with 6 notches, the last two being made by grinding.

At its opposite end to the part 4, the implant body 1 continues with a smooth shoulder 6 in the form of a truncated cone of revolution tapering away from said cylindrical portion 3. This part 6 is part of a cone of 4 ° (ie a half-angle at the top of 2 °). The implant body portion 1 is intended to be immobilized by screwing into the mandibular or maxillary bone, the smooth shoulder portion 6 coming into contact with the cortex. During screwing, the conical shoulder 6, thanks to the chosen conicity, can expand the cortical zone of the bone, which allows to obtain an instant anti-withdrawal effect and allows the practitioner some latitude for possible to refine the positioning of the implant by screwing, and finally, and this is not the least important, ensures a good sealing of the insertion thanks to a perfect joint plane between the cortical zone and the shoulder, which allows to avoid the risks of bacterial development. The implant has a second portion called pillar portion 2 which, when the implant is in place, will protrude from the bone to receive an external dental device.

The abutment portion 2 is connected to the smooth shoulder 6 by a cone-like enlargement 7 called gingival, slightly convex, the top 8 of which carries the pillar 2a.

When the implant is in place, the portion 7 is in contact with the gum, while the pillar 2a receives the external dental device or prosthesis (not shown)

As can be seen in the section of Figure 3, respectively 4, the pillar 2a has 4 or 3 flats 10 can cooperate with a suitable screw wrench, not shown. They are also intended to prevent the possible rotation of the prosthesis.

The implant shown in Figure 1 is a straight implant and the implant body portion and the abutment portion extend on the same longitudinal axis L.

A well 9 of polygonal section (see section of Figure 3) crosses the entire length of the pillar to end in the conical widening being centered on the aforementioned longitudinal axis.

FIG. 2 shows an implant of the same type with the difference, a pillar portion inclined at an angle of 18 ° with respect to the longitudinal axis L of the implant body 1. It will be noted that the well 9 of polygonal section remains aligned on this longitudinal axis.

The wells 9 are intended to cooperate with a key of complementary shape that is inserted into the well to allow the screwing of the implant. This mode allows the establishment of an implant where an external screw wrench (the one cooperating with the flats 10) is made difficult or impossible by the presence of adjacent teeth.

In contrast to the representation of FIG. 1, the apex 8 of the conical widening 7 of FIG. 2 is curved for structural reinforcement purposes.

FIGS. 6 and 7 represent so-called ball implants whose implant body portion 1 is identical to that described with reference to FIGS. 1 and 2. The ball-type abutment portion is as commonly used for placing in place of a possibly removable dental appliance on the lower jaw.

FIG. 6 represents a right implant and FIG. 7 shows an implant whose abutment portion is inclined at 18 ° with respect to the axis of the implant body.

The polygonal part comprises a conical section 16 provided with three flats of which only one is represented in FIG. 6 or 7 under the reference 18, this section being connected to the spherical portion or ball 17 by a constriction 19.

The dental drill 20 shown in FIG. 8 is intended to pierce a hole in a jawbone for inserting an implant according to the invention.

The drill extends along a longitudinal axis L, and comprises an active longitudinal portion threaded 21 for drilling inside a jaw bone, and a longitudinal connecting portion or pin 22 for connecting the drill 20 to rotation drive means about the axis L.

The active part 21 is substantially symmetrical in revolution about the axis L. It is stepped, and comprises from its free end towards the spindle 22 a first cylindrical section 23, a second frustoconical section 24 which fits into a cone having a slope of 2 °, and a third cylindrical section 25.

The second section 24 is connected to the first section 23 by a radial shoulder 26 cutting, and the third section 25 by a radial non-cutting shoulder 27, serving as a stop.

The threads 28, for example four in number, extend helically around the axis L from the free end 29 of the first section 23, and up to substantially half of the third section 25.

The free end 29 of the first section 23 is conical, and has a large cone angle, to facilitate the centering of the drill 20 at the beginning of the drilling operation.

As shown in FIG. 9, the section of the drill bit 20 has a general four-branch Maltese cross pattern. More specifically, the threads 28, each constituting a branch of the pattern, widen away from the center of the drill 20.

The threads 28 are substantially identical and angularly distributed regularly around the axis L.

Each net 28 comprises a top surface 30 and two sidewalls 31. The top surface 30 is a cylindrical surface portion of the diameter of the first section 23.

Each flank 31 joins the top surface forming a cutting lip 33, so that each thread 28 has two cutting lips 32 parallel. The presence of two lips results from the machining process. Only one per thread, however, is sufficient for the drilling operation, namely that located at the head in the direction of rotation of the drill.

The bottom of net 33 separating two adjacent threads 27 is concave. Pin 22 is of conventional type, with a flat 34 for coupling in rotation about the axis L, and an annular groove 35 for its longitudinal coupling.

To set up an implant according to the invention, the practitioner removes a lozenge of gingiva from the trephine, may first drill a hole in the bone with a pilot drill of small diameter, and then drill into the bone with the drill bit. adapted in diameter and length to the implant, until reaching the stop. Preferably, the drill makes it possible to make a slightly longer well (e.g., 1 mm) than the implant body. Also preferably, the second section 24 of the drill drills a cone of diameter slightly smaller than that of the conical shoulder 6 of the implant body.

If necessary, once the drilling is done, the practitioner searches for the correct implant of the game by using a set of angle indicators of less length, of the same diameter and taper at the level of the cortex of the bone. It verifies what indicator gives, once placed in the drilled well, the good parallelism of the pillar with the neighboring dental structures and chooses, therefore, the implant having the right angle. After removing the angle indicator, he introduces the final implant by screwing it into the drilled well, using a wrench that fits around the abutment and its flats, or a special polygonal tool that fits into the well. 9. The practitioner fully screws the implant until the conical shoulder of the implant body rests on the conical portion of the cortex. He finishes the screwing when the pillar is well oriented.

The prosthesis can be placed on the abutment after a shorter period.

The invention also relates to an assembly (kit) comprising the implants of a set, a wrench capable of cooperating with the outer surface of the abutment and / or a polygonal end wrench capable of cooperating with the polygonal well, and possibly, a set of angle indicators. Reference is now made to FIG.

In the preferred embodiment of the invention, the zirconia implant is made by high-pressure molding, followed by high-temperature sintering (generally between 1400 and 1500 ° C.). The size of the molds takes into account the shrinkage during sintering.

Note that a non-illustrated variant provides for the implants by grinding small cylinders obtained by high compression, and optionally sintering.

It is advantageous to mold a plurality of implants at one time, for example the six implants of a set of implants according to the invention, by using a multiple mold, of which one of the halves in FIG. It is also possible to temporarily condemn certain sectors when the inclination or the corresponding implant length is not desired.

This multiple mold has indeed a plurality of sectors of a circle which is seen from above the sectors 34a to 34f of the lower mold half. Each sector comprises, disposed radially, a half-cavity 35a to 35f for the implant. It is therefore understood that each of the sectors 34a to 34f will be covered with an associated sector, symmetrical with respect to the plane of the figure, and comprising the symmetrical half-cavity so as to achieve the complete impression.

It can be seen in the figure that the sectors 34a, 34b and 34c correspond to three implants having the same diameter and the same length of implant body, but different inclinations (for the simplicity of the drawing, the imprints have been drawn schematically). Sector 34a shows a right implant 1 as it appears after demolding resting in the half-cavity. Sector 34b defines an implant of the same size with an angle of 9 °. Sector 34c defines an implant with an angle of 18 °. It is understood that the other sectors may include impressions for implants with diameters, lengths and / or different angles. The halfprints of each sector are connected to a central half-chamber 36 by as many radial channels 37, these radial channels being likely to be blocked by injection shutters After selecting the implants to be made, a removable insert is inserted in each half-cavity, on the pillar side, in order to obtain in each implant, the polygonal well 9 (see FIG. 1) which will be used to screw the implant. implant. It is therefore understood that when the entire mold is assembled, it suffices to introduce into the volume constituted by the superposition of the two half-chambers 36, the fluid preparation of zirconia under pressure, so that the zirconia passing through those of the channels of which has previously removed the shutter 38, fills the fingerprints formed by the superimposition of complementary half-impressions. The demolding is carried out by separating the two half-molds and then simply extracting the molded implants 1, possibly by means of ejectors provided for this purpose in the mold.

The sectors can therefore be chosen according to the needs of the type of implant. The eight implants of a set of implants of the same length and diameter, but having all the body-abutment angles of a complete set, can thus be molded in one go. However, if certain implants of the game are used more frequently than others, for example those having a zero angle or a small angle, it is also possible to use several sectors having absolutely identical half-impressions to mold a set comprising identical implants and others having a different angle. It is also possible, thanks to the shutters 38, to mold only those implants that are needed more frequently.

However all other combinations are possible and allow to adapt very precisely to the instant demand of implants that can be addressed by customers.

Claims

A one-piece dental implant having an implant body portion (1) arranged to be immobilizable in the mandibular or maxillary bone and a pillar portion (2) arranged to protrude from the bone to receive an external dental device, provided with a screw-like implant body (1), substantially symmetrical in revolution around a longitudinal axis (L) and comprising a threaded central cylindrical portion (3), continuing with a self-tapping end portion ( 4) substantially conical tapering away from the portion (3) and provided on its periphery with cutting notches (5) longitudinal at its other end, the cylindrical central portion (3) continuing with a smooth shoulder ( 6) flaring away from the cylindrical portion (3), the dental implant being made of zirconia by molding and sintering, or by molding, sintering and grinding.

2. Implant according to claim 1, characterized in that the end portion (4) comprises from 4 to 12 cutting notches (5), preferably from 6 to 10.

3. Implant according to claim 1, characterized in that it comprises eight notches (5), six from molding and two being made by grinding.

4. Implant according to any one of claims 1 to 3, characterized in that the end portion (4) is substantially in a truncated cone of 10 to 30 °, preferably 16 to 24 °, eg 20 ° .

5. Implant according to any one of claims 1 to 4, _^ characterized in that the smooth shoulder (6) is part of a cone of revolution 2 ° to 6 °, preferably 3 ° to 5 °, preferably 4 °, and has a length of a few millimeters, preferably 1 to 3 mm, more preferably 2 to 2.5 mm.

6. Implant according to any one of claims 1 to 5, characterized in that the axis of the pillar (2a) is inclined relative to the longitudinal axis (L) of the implant body (I) between 0 ° and 30 °.

7. Implant according to any one of claims 1 to 6, characterized in that a well (9) having a polygonal section passes through the pillar portion (2) being centered on the longitudinal axis (L) of the implant body (I).

A one-piece dental implant having an implant body portion (1) arranged to be immobilizable in the mandibular or maxillary bone and a pillar portion (2) arranged to protrude from the bone to receive an external dental device, provided with a screw-like implant body (1), substantially symmetrical in revolution around a longitudinal axis (L) and comprising a threaded central cylindrical portion (3), continuing with a self-tapping end portion ( 4) substantially conical tapering away from the portion (3) and provided on its periphery with cutting notches (5) longitudinal at its other end, the cylindrical central portion (3) continuing with a smooth shoulder ( 6) flaring away from the cylindrical portion (3), the axis of the pillar (2a) being inclined with respect to the longitudinal axis (L) of the implant body (1) and a well ( 9) having a polygonal section crossing the p pillar section (2) being centered on the longitudinal axis (L) of the implant body (1).

9. Implant according to claim 8, characterized in that the well (9) extends into the smooth conical enlargement (7) and has a polygonal section therein.

10. Implant according to claim 9 or 10, characterized in that it is made of zirconia.

11. Implant according to claim 10, characterized in that it is produced by molding and sintering, or by molding, sintering and grinding, at least some of the notches coming from molding.

12. Set of implants comprising at least two implants according to any one of the preceding claims and having different implant / abutment body angles.