Technical field

The present invention relates to the field of implants and more particularly dental implant distractor combining a dental implant and a distractor in such a way that a dental implantation can be made by adding the height of the resorpted alveolar ridge from 4 mm to more than 10 mm in a one stage surgical technique without complications of distractors of prior art.

Prior art

A dental implant usually includes a generally cylindrical body, an interior bore and non-rotational means. The generally cylindrical body is generally divided into an upper or proximal portion and a lower or distal portion. The distal portion is typically for anchoring the dental implant in bone of a patient, such as a patient's maxilla or mandible. The proximal portion includes first threads about an exterior surface thereof and the distal portion includes second threads about an exterior surface thereof. In some implementations, the first and second threads are the same, i.e. same pitch, same cross-section, and/or same number of starts, etc., and in some alternatives, the first and the second threads are different. Said non-rotational means are external or internal to the interior bore and is usually a six-sided hexagonal boss or recess that can non-rotationally mate with a corresponding non-rotational feature of an abutment in a non-rotational fashion.

In oral rehabilitation using an implant, the patient receiving the implant must have a bed with sufficient bone volume and height for the implant, to providing adequate stability for the implant.

If the patient has a bed with sufficient bone volume and height, a one stage surgical technique, also called non-buried technique, with immediate loading implant placement can be performed. In the so-called non-buried technique, the surgeon sets up the implant consisting of a generally cylindrical, conical, or cylindro-conical socket provided with a thread and at the upper end of which is located an implant neck adapted to receive the prosthetic system. The implant is placed either by opening the gum above the implantation area or by passing directly through the gingiva according to the so-called transmucosal technique and then by practicing an implantary at the chosen depth according to the patient's bone volume, the length of the implant determining the depth of said implant socket. If the patient hasn’t a bed with sufficient bone volume and height, the patient will require an alveolar ridge reconstruction to increase the bone volume in which the implant will subsequently be embedded in the socket. Different methods are used to perform the alveolar ridge reconstruction. In case of a slight lack of bone width, methods such as autologous bone graft, bone spreading, bone splitting, bone block transplantation, sinus lift, cavity techniques, alloplastic materials are used.

Nevertheless, the availability of such grafts is limited and they show a high resorption rate after transplantation. Moreover, they provide insufficient bone quality, and so implants are not securely anchored in their implant sockets. In addition, the bone replacement is frequently not sufficiently vascularized, which increases the risk of infection and affects the regeneration of the bone. In addition, growth factors are frequently used in methods from the prior art, which significantly increase the costs for the procedures. Furthermore, such methods make it necessary to wait for approximately six months between each surgical procedure for the ridge to increase in size and the implant to be inserted into the implant socket.

To overcome these drawbacks, an alveolar distraction process can be performed. To perform the alveolar distraction, a traction force is applied to a portion of the bone, which is shifted vertically to reach the optimum or planned height. The shifting of this fragment leads to the regeneration of the tissues, both the hard tissue (bone) and the soft tissue (gum) during that process. To execute the alveolar distraction, it is necessary to perform an osteotomy (cutting of the bone) to release a bone fragment (plate), leaving a free area (osteotomy line) between the bone fragment and the rest of the jaw and different devices called alveolar distractors are well known. It is the case notably of the US patent US 6’537’070, the US patent applications US 2015/0250566 and US 2015/0313689 and the international patent application WO2015/1 14040.

The document US 6’537O70 discloses a combination dental implant/prosthetic support and distractor for facilitating distraction osteogenesis comprises a basically cylindrical shaft having a set of threads on the outside surface and a smooth, distal tip which bears against the bone of the jaw of the patient. Rotation of the device in the mouth of the patient, after a suitable surgical cut is made, causes the adjacent tissue to move or ride up the screw threads to create space between the cut jaw segment and the balance of the jaw tissue. This space is then filled in by distraction osteogenesis.

This device has the disadvantage of requiring manipulation of the surgeon, mainly a rotation of the upper part, incrementally in such a way that several surgical procedures are necessary. The document US 2015/0250566 discloses an alveolar ridge distractor for distracting a bone fragment with respect to a maxillary bone separated by an osteotomy line. The distractor is comprised of a threaded rod with an upper piece and a lower piece. The threaded rod is formed by a top part where the thread has a specific rotation direction and a bottom part where the rotation direction of the thread is opposite to that of the top part of the rod. The upper piece is located at the top of the rod and the lower piece is located at the bottom part of the rod. Both bodies have an end part with no external thread, generating a free ring in the area in which both bodies are joined, with no thread. That free ring which is not threaded, is positioned to coincide with the osteotomy line.

This distractor has the drawback of having to be removed after the distraction and before proceeding with the implant installation. The document US 2015/0313689 discloses an implant for bone distraction including an implant body and a distraction membrane. The distraction membrane is connected to the implant by a connection element. The connection element is arranged movably at least over a portion of a longitudinal axis of the implant body such that the distraction membrane is slidable along at least a portion of the longitudinal axis of the implant body.

This device is aimed at creating a new bone between alveolar ridge and the distractor membrane. Nevertheless, it is impossible since the principle of distraction is bone callus mechanical elongation through progressive separation under tension of two bone fragments surrounding callus to achieve new bone formation. Moreover, this device cannot increase alveolar bone height more than adjacent bone levels.

The document WO2015/114040 discloses a dental implant, comprising an implant body and a distraction membrane, to the use of the implant for callus distraction and to a method for implanting, the implant comprising a movable connection element between the implant body and the distraction membrane.

All these devices have the disadvantage of requiring manipulation of the surgeon in such a way that several surgical procedures are necessary. Moreover, these devices have some protruding part out of the alveolar ridge area and are in contact with oral cavities, saliva and microflora. Hence, the protruding part of these devices cannot be sterilized and will not have any osseointegration around the proximal portion of the implant’s body. Furthermore, tongue, chewing muscles and chewing function will cause micro movements of the external part of these devices but it is well known that micro movements more than 10 microns at early stages of bone healing is enough to shift differentiation of mesenchymal cells from osteoblasts to fibroblasts in such a manner that the bone regeneration will be lost. Disclosure of the invention

It is the aim of the present invention to provide a device that allows the height of the alveolar ridge to be increased, even more than adjacent bone level, that is compatible to prosthetic past for a usual prosthesis, that has no connection with oral cavity to avoid risk of micro movement, infection and graft contamination, and that provides a dental implantation in a one stage surgical technique.

According to the present invention, the aforementioned aim is achieved by means of a dental implant extractor comprising at least a generally cylindrical main body including conical teeth about its exterior surface, an interior bore and non- rotational means wherein it further comprises an extractor module having a cylindrical shape and comprising threads about its exterior surface, means for guiding said extractor module along the longitudinal axis of the generally cylindrical main body, means cooperating with first threads of the exterior surface of the generally cylindrical main body to move incrementally the extractor module from the proximal portion to the distal portion of the generally cylindrical main body, and abutment means at the distal end of the generally cylindrical main body to stop the extractor module.

Said means for guiding the extractor module consist in at least one lug protruding towards the center of the extractor module and sliding in a longitudinal groove made in the generally cylindrical main body. Preferably, said means for guiding the extractor module consist in two lugs protruding towards the center of the extractor module, the lugs being diametrically opposed, and sliding in two diametrically opposed longitudinal grooves made in the generally cylindrical main body. Moreover, said means for moving incrementally the extractor module consist in at least two diametrically opposed ergots protruding towards the center of the extractor module from the distal end of the extractor module.

Said abutment means consist in a collar extending from the distal end of the generally cylindrical main body.

Furthermore, the non-rotational means are recessed from the proximal end of the cylindrical body and is coaxial to the interior bore. Said non-rotational means are preferably a six-sided hexagonal recess that can non-rotationally mate with a corresponding non-rotational feature of a prosthetic system. Incidentally, the proximal end of the cylindrical body presents a conical opening.

Preferably, the generally cylindrical main body is divided into an upper or proximal portion and a lower or distal portion, the distal portion having an outer diameter smaller than the outer diameter of the proximal portion.

Said proximal portion includes conical teeth, forming with the proximal portion a cylindrical rack, about an exterior surface thereof and the distal portion includes threads about an exterior surface thereof.

Advantageously, the distal portion of the generally cylindrical body includes at least one vertical flute extending from the distal end of the distal portion to the proximal portion. Brief description of the drawings

The foregoing and other advantages of the present disclosure will become more apparent upon reading the following detailed description and upon reference to the drawings.

- Figure 1 is an exploded perspective view of a dental implant with an extractor module according to the invention,

- Figure 2 is a perspective view of the main body of the dental implant according to the invention,

- Figure 3 is a bottom view of the main body of the dental implant according to the invention,

- Figure 4 is a top view of the main body of the dental implant according to the invention, - Figure 5 is a perspective view of the extractor module of the dental implant according to the invention,

- Figure 6 is a bottom view of the extractor module of the dental implant according to the invention,

- Figure 7 is an elevation view of the extractor module of the dental implant according to the invention,

- Figure 8 is an elevation view, according to a perpendicular plane of the cut plane of figure 7, of the extractor module of the dental implant according to the invention,

- Figure 9 is a perspective view of the dental implant extractor in its up position according to the invention,

- Figure 10 is a perspective view of the dental implant extractor in its low position according to the invention,

- Figure 1 1 is a longitudinal section view of the dental implant extractor in its low position according to the invention,

- Figure 12 is a perspective cutaway view of the dental implant extractor in its low position according to the invention,

- Figure 13 is a perspective view of the dental implant extractor in its low position according to the invention,

- Figure 14 is a longitudinal section view of the dental implant extractor in its up position according to the invention.

Description of preferred embodiments The present invention will be described with respect to particular embodiments and with reference to certain drawings. The invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not necessarily correspond to actual reductions to practice of the invention. Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. The terms are interchangeable under appropriate circumstances and the embodiments of the invention can operate in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. The terms so used are interchangeable under appropriate circumstances and the embodiments of the invention described herein can operate in other orientations than described or illustrated herein. The term“comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It needs to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression“a device comprising means A and B” should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

Referring to figures 1 and 5 to 12, the dental implant extractor according to the invention comprises a generally cylindrical main body 1 , an interior bore 2 and non- rotational means 3. The dental implant extractor further comprises an extractor module 4 having a cylindrical ring shape, means 5 for guiding said extractor module 4 along the longitudinal axis of the generally cylindrical main body 1 , and abutment means 6 at the distal end of the generally cylindrical main body 1 to stop the extractor module 4.

The generally cylindrical main body 1 , referring to figures 1 to 4 and 9 to 12, is divided into an upper or proximal portion 1 a and a lower or distal portion 1 b wherein the distal portion has an outer diameter smaller than the outer diameter of the proximal portion. Said distal portion 1 b is typically for anchoring the dental implant in bone of a patient. For example, the dental implant 1 can be anchored into a patient's maxilla or mandible. The proximal portion 1 a includes conical teeth 7, forming with the proximal portion 1 a a cylindrical rack, about an exterior surface thereof and the distal portion 1 b includes threads 8 about an exterior surface thereof. For example, the threads 8 of the distal portion can be a multi-lead thread with three threads each having a pitch of 0.3 to 1 millimeters or a single thread having a pitch of 0.3 to 1 millimeters. Various alternative threads, pitches, and ratios are contemplated, such as multi-lead threads for example.

The distal portion 1 b of the generally cylindrical body 1 includes three vertical flutes 9 distributed around distal portion 1 b of the generally cylindrical body 1 and extending from the distal end of the distal portion 1 b to the proximal portion 1 a. Said distal portion 1 b can includes one or a plurality of flutes 9 (two, three, four, etc.) spaced about the circumference of the distal portion 1 b that cross (e.g., break up) the threads 8 without departing from the scope of the invention. The flute(s) 9 aid the installation of the dental implant by self-tapping the dental implant into the patient's bone socket and/or by providing a path for material to be ejected from the cavity (e.g., bone socket) receiving the dental implant during installation.

The proximal portion 1 a of the generally cylindrical body 1 also includes a collar 10 which forms said abutment means 6. The collar 10 is generally cylindrical and is positioned at the proximal end of the dental implant. It should be noted that said collar 10 can be positioned near the proximal end of the dental implant and/or can be substituted by any equivalent abutment means without departing from the scope of the invention. Said collar 10 has a maximum outer diameter that is slightly larger than the maximum outer diameter of the rest of the proximal portion 1 a, which is defined by the outer diameter of the conical teeth 7 of the proximal portion 1 a. Moreover, the proximal portion includes a smooth portion 11 , i.e. a portion without conical teeth 7, extending under the collar 10 and on a height substantially equal to the height of the extractor module 4. In this manner, the extractor module 4 can freely rotate around the generally cylindrical body 1 when said extractor module 4 is positioned in its upper position where it extends at the level of the smooth portion 1 1.

Referring to figures 1 and 5 to 12, the extractor module 4 has a cylindrical ring shape presenting an internal diameter that is slightly larger than the maximum outer diameter of the proximal portion 1 a, which is defined by the outer diameter of the conical teeth 7 of the proximal portion 1 a and an external diameter that is slightly smaller than the maximum outer diameter of the collar 10. Said extractor module 4 comprises two lugs 12 protruding towards the center of the extractor module, the lugs 12 being diametrically opposed and extending from the proximal end to the distal end of the extractor module 4. Said lugs 12 are sliding in two diametrically opposed longitudinal grooves 13 made in the generally cylindrical main body 1 and that cross (e.g., break up) the conical teeth 7. Hence, the extractor module 4 can slide along the cylindrical body 1 without any movement of rotation. Moreover, the extractor module includes second threads 14 about an exterior surface thereof. For example, the second threads 14 of the extractor module 4 can be a multi-lead thread with three threads each having a pitch of 0.3 to 1 millimeters or a single thread having a pitch of 0.3 to 1 millimeters. Various alternative threads, pitches, and ratios are contemplated, such as multi-lead threads for example Furthermore, the extractor module 4 includes means for moving incrementally the extractor module 4 along the longitudinal axis of the cylindrical body 1. Said means consist in two diametrically opposed ergots 15, having a curved blade shape and being slightly flexible, protruding towards the center of the extractor module 4 from the proximal end, i.e. from the lower end, of said extractor module 4. The free ends of the ergots rest on the inclined part of the conical teeth 7 of the proximal portion 1 a. In addition, the extraction module 4 comprises two holes 16 diametrically opposed to its proximal end, i.e. at its upper end, adapted to receive a titanium wire, not shown in the figures, allowing the surgeon to move upwardly said module of extraction as it will be detailed further.

Incidentally, referring to figures 1 , 2, 4 and 9 to 12, the non-rotational means 3 is recessed from the proximal end of the cylindrical body 1 and is coaxial to the interior bore 2, the proximal end of the cylindrical body 1 presenting advantageously a conical opening 17. As shown, the non-rotational means 3 is a six-sided hexagonal recess that can non-rotationally mate with a corresponding non-rotational feature of a prosthetic system (not shown). Various alternative non-rotational means are contemplated, such as, for example, a four-sided square or rectangular recess (not shown), a five-sided polygonal recess (not shown), a twelve-sided polygonal/star recess (not shown), a three-piece clover shaped recess (not shown), etc. We will explain below the operation of the implant according to the invention with reference to Figures 13 and 14. Referring to figure 13, the resorpted alveolar ridge with an height of approximately 4 mm is cut horizontally at half height, i.e. approximately at 2 mm, then an implant socket is drilled for 4 mm vertically and the dental implant according to the invention with the extractor module positioned at its lower position is introduced into the implant socket. Then, the alveolar ridge is cut sensibly vertically all around the dental implant at a distance of approximatively 3 mm from the outer diameter of said dental implant and at a depth of at least 4 mm. Hence, the distal portion 1 b of the implant is fixed into at least 2 mm of the implant socket and approximately 2 mm of free bone is fixed to the extractor module 4. Referring to figure 14, the extractor module 4 and the free bone attached into is moved up to the proximal end of the dental implant, i.e. until the extractor module 4 is in abutment with the collar 10 of the generally cylindrical body 1 , incrementally or in one stage. Hence, the extractor module 4 can be moved from this lower position to its upper position, i.e. about 6-7.5 mm, in one stage or can be moved incrementally by 0.5 to 1 mm day after day. To this end, a titanium wire is passed through the holes 16 of the extractor module 4 in such a way that the surgeon grap the titanium wire and pull it up in one stage or incrementally. According to the one stage method, the surgeon cut the titanium wire during surgery and, according to the incrementally method, the surgeon cut the titanium wire almost two weeks after the surgery because it is essential for the movement of the bone. The extractor module 4 is fixed in its upper position and the volume between the bottom of the ridge and the free bone attached to the extractor module 4 fills with bone callus. In this manner, after bone regeneration, a usual prosthetic system can be fixed to the generally cylindrical body 1 using the interior bore 2 which is compatible to most of prosthetic parts for usual dental prosthesis. The dental implant according to the invention is positioned under the gingiva and have no connection with oral cavity in such a manner that micro-movement, infection and graft contamination is avoided. Moreover, if necessary, a ridge higher than adjacent bone level can be obtained by using the dental implant according to the invention. Furthermore, according to an essential characteristic, the distraction and the implantation is in one stage causing minimum trauma to the patient.

It should be noted that, throughout the present disclosure, reference is made to any sized dental implants.

Moreover, it will be understood by those skilled in the art that the present invention is not limited to the embodiments illustrated above and that many modifications and additions may be made without departing from the scope of the invention as defined in the appending claims.