Dental burr

Abstract

The dental bun (1) comprises: - a proximal non-working portion (2) connectable to a tool for setting in rotation (S); a cylindrical diamond working portion (3) associated with the proximal non¬ working portion (2); - a conical diamond working portion (4) associated with the cylindrical diamond working portion (3) and having a decreasing diameter along the direction of departure from the cylindrical diamond working portion (3); - a non-diamond working lanceolate tip (5) associated with the conical diamond working portion (4).

Description

[0001] DENTAL BURR

[0002] Technical Field

[0003] The present invention relates to a dental burr, which is specifically intended for performing trans-nasal and trans-sinus dental implant surgery.

[0004] Background Art

[0005] As is well known, a dental implant substantially consists of a screw which is placed inside the alveolar bone to replace a tooth that has been extracted or is missing.

[0006] This allows an abutment protruding externally from the cavity and serving a structural function to be attached thereto.

[0007] The abutment can be of various types and can be replaced if, e.g., it is damaged. Finally, the dental crown is placed on the abutment, replacing the missing tooth in appearance and functionality.

[0008] In case of complete implant rehabilitation of the edentulous maxillary dental arch, it is sometimes necessary to place a dental implant through the nasal cavity or maxillary sinus cavity.

[0009] This occurs specifically when the patient has vertical bone atrophy in the incisor area or premolar / molar area, respectively, and bone grafting techniques are to be avoided.

[0010] The aforementioned implants, known as “trans-nasal” and “trans-sinus” implants, are inserted starting from the residual bone crest in the incisor area or premolar / molar area and are angled, passing through the nasal cavity or the maxillary sinus cavity, to fasten themselves at their apical stretches to the surface of the maxillary bone facing the cavities themselves.

[0011] The installation of trans-nasal and trans-sinus implants allows avoiding traditional bone regeneration techniques in patients, which are more invasive, require longer treatment times, are more expensive and carry a higher risk of infection.

[0012] In these cases, in fact, the patient not only has to undergo several operations spread over a relatively long period of time, but also, precisely because of this, is left without teeth for a long time, with obvious functional and aesthetic discomfort.

[0013] In addition, the morbidity of implant treatment is much higher in the case of bone regeneration techniques, as is the need for medication due to the numerous surgical operations.

[0014] On the other hand, the placement of a trans-nasal or trans-sinus implant has numerous advantages, including: the placement of a longer implant that fastens into the native bone; the creation of a tricortical structure (i.e., the residual bone crest, the maxillary sinus cortex and the nasal cortex) to increase implant fastening; the reduction of the prosthetic cantilever which allows avoiding excessive stress on the implant-abutment and abutment-prosthesis connection screws.

[0015] Therefore, when possible, the placement of a trans-nasal or trans-sinus implant represents a “graftless” solution that is currently highly appreciated by dental surgeons and patients.

[0016] With particular reference to trans-nasal or trans-sinus implant installation surgery, the use is known of kits of constant-section cylindrical burrs working along their entire length aimed at removing part of the bone to allow the dental implant to be installed at the target bone portion, i.e., the maxillary bone onto which the apical end of the implant itself is screwed.

[0017] This burring operation is necessary, in particular, to ensure that the implant has sufficient space to be grafted into the target bone and, at the same time, to ensure that the implant is inserted through the nasal cavity or maxillary sinus at the correct angle.

[0018] It should be borne in mind that trans-nasal or trans-sinus implants must be inserted at a very precise angle in order to reach the target bone.

[0019] Otherwise, the implant would be installed in an inconveniently precarious and unstable position, thus affecting the success of the implant rehabilitation.

[0020] Taking all this into account, the use of the above-mentioned known burrs is not recommended for the preparation of trans-nasal and trans-sinus implants for the following reasons: the preparation of trans-nasal and trans-sinus implants must be differentiated between the coronal part and the apical part. Passing through a certain portion of the nasal cavity or sinus cavity, the trans-nasal or trans-sinus implant is in a “vacuum” for a variable stretch depending on the pneumatization of the nasal cavity or sinus. It is therefore essential to adequately underprepare the apical portion of the osteotomy at the target bone to stabilize the apex of the implant. This underpreparation cannot however be also done at the level of the residual bone crest, as this would lead to excessive compression of the cortex with consequent resorption thereof, even to the point of fracture of the residual bone crest. once the burrs have penetrated the nasal cavity in the incisor area or the maxillary sinus in the premolar / molar area, it is necessary to perforate the nasal cavity or maxillary sinus again to reach the target bone. In this case, the burr is used on an inclined cortical bone surface, and it is very difficult to maintain the desired angle of the burr because the tip thereof tends to slip upward on the inclined surface. This slipping can cause the dentist to lose control of the tool and to perforate the lateral wall of the nose, where the bone quantity and quality is much poorer than the cortical bone located further down, drastically reducing the stability of the trans-nasal and trans-sinus implant. In addition, the slipping of the burr tip upwards may result in loss of control of the tool and interference with important anatomical structures (nasolacrimal duct, sinus canal, etc.). the use of multiple dental burrs to make a blind hole with very precise diameter and depth on a surface of the maxillary bone facing the nasal cavity or on the sinus cavity is inconvenient for the dentist, as it requires a large number of steps, with a higher probability of error, risk of contamination and complications that may occur both during and after surgery.

[0021] In other words, the surgical technique just described greatly complicates bone perforation surgery for the dentist, who runs the real risk of installing the implant at an incorrect angle, resulting in instability of the implant itself and therefore making it impossible to use it to support prosthetic rehabilitation. In actual facts, the success or failure of the operation on the patient is entrusted to and critically depends on the manual skills of the demist alone.

[0022] Description of the Invention

[0023] The main aim of the present invention is to devise a dental burr which allows at least partial improvements to be made to the aforementioned drawbacks.

[0024] In particular, one object of the present invention is to devise a dental burr that allows simplifying surgical procedures and reducing treatment times, with a consequent reduction in risks for both the dentist and the patient.

[0025] Another object of the present invention, related to the one just described, is to devise a dental burr that allows decreasing the number of steps required to perform implant osteotomy surgery and consequently reducing the margin of error.

[0026] A further object of the present invention is to devise a dental burr that allows dental implant surgery to be performed with greater precision and control by the dentist, greater predictability of results and with few and simple surgical steps.

[0027] Last but not least, the object of the present invention is to devise a dental burr that allows making it easier for the dentist to handle the burr itself and to perforate the target bone for correct and precise positioning of the implant.

[0028] Another object of the present invention is to devise a dental burr that reduces the risk of contact between the burr itself and the tissues adjacent to the area to be operated on.

[0029] Furthermore, a further object of the present invention is to devise a dental burr that allows limiting the possible complications that may occur during and after surgery and, specifically, reducing the risk of contamination.

[0030] Another object of the present invention is to apply these improvements in the context of a wide range of surgical cases.

[0031] Finally, the object of the present invention is to devise a dental burr that allows the aforementioned drawbacks of the prior art to be overcome with a simple, rational, easy and effective to use, as well as inexpensive solution.

[0032] The aforementioned objects are achieved by the present dental burr having the characteristics of claim 1.

[0033] Brief Description of the E Other characteristics and advantages or me present invention will be more apparent from the description of a preferred, but not exclusive, embodiment of a dental burr, illustrated by way of an indicative, yet non-limiting example, in the accompanying drawings, in which:

[0034] Figure 1 is an axonometric view of the dental burr according to the invention;

[0035] Figure 2 is a lateral view of the dental burr according to the invention;

[0036] Figure 3 is a lateral view, from another angle, of the dental burr according to the invention;

[0037] Figure 4 is a front view of the dental burr according to the invention;

[0038] Figures 5 to 10 show, in a sequence of cross-sectional views, the operation of the dental burr according to the invention.

[0039] Embodiments of the Invention

[0040] With particular reference to these figures, reference numeral 1 globally denotes a dental burr.

[0041] The dental burr 1 comprises: at least one proximal non-working portion 2 connectable to a tool for setting in rotation S, e.g. of the type of a dental drill; at least one cylindrical diamond working portion 3 associated with the proximal non- working portion 2; at least one conical diamond working portion 4 associated with the cylindrical diamond working portion 3 and having a decreasing diameter along the direction of departure from the cylindrical diamond working portion 3; and at least one non-diamond working lanceolate tip 5 associated with the conical diamond working portion 4.

[0042] In this regard, it should be specified that, in the context of this disclosure, the term “proximal”, as well as the antonymous term “distal”, is used with reference to the position of the various components with respect to the tool for setting in rotation S.

[0043] Therefore, the proximal non-working portion 2 represents a segment of the dental burr 1 which, in use, is intended to be placed closer to the tool for setting in rotation S, while the non-diamond working lanceolate tip 5, which is located at the distal position on the opposite side oi me proximal non-working portion 2, is intended to be positioned, in use, further away from the tool for setting in rotation S.

[0044] The dental burr 1 is configured to perforate the patient’s maxillary bone M in such a way as to create a passage for the insertion and installation (i.e., screwing into the bone) of an implant I.

[0045] In particular, the dental burr 1 is configured and specially designed to: perforate the maxillary bone M at the maxillary bone crest Ml, so as to make a through hole Fl that communicates with a cavity C of the maxillary bone M, e.g. the nasal cavity or the maxillary sinus cavity; pass through the cavity C and perforate a surface M2 of the maxillary bone M facing the cavity C, so as to make a blind hole F2; if necessary, remove the maxillary bone M at the maxillary bone crest Ml and at the surface M2 by gently oscillating the dental burr 1 around the nondiamond working lanceolate tip 5 fitted into the blind hole F2, which thus serves as a rotational pivot.

[0046] In the particular embodiment shown in the figures, the cavity C is the nasal cavity and the dental burr 1 is specifically sized to work inside it.

[0047] It cannot, however, be ruled out that the same dental burr 1 may also be used in the maxillary sinus cavity and / or may have some minor dimensional adjustment to better suit the purpose.

[0048] Advantageously, the proximal non-working portion 2, the cylindrical diamond working portion 3, the conical diamond working portion 4 and the non-diamond working lanceolate tip 5 are aligned along a geometric axis that coincides with an axis of rotation A of the dental burr 1.

[0049] The proximal non-working portion 2 preferably consists of a segment provided with a shaped end 6, configured to be connected to the tool for setting in rotation S, and with an end, opposite the previous one, connected to the cylindrical diamond working portion 3.

[0050] At least one of either the cylindrical diamond working portion 3 or the conical diamond working portion 4, preferably both, is coated with a diamond layer having a grit of between DI 26 and D2 1, preferably of between D151 and D213, preferably equal to D181.

[0051] As is known, the grit of superabrasive materials (e.g. diamond and cubic boron nitride) is measured according to ISO 6106, which establishes different categories, from the finest (e.g. D33) to the coarsest (e.g. DI 181); the particular expedient of providing for a grit of between D126 and D251, better still of between D151 and D213, preferably equal to D 181, in actual facts, ensures that the cylindrical diamond working portion 3 and the conical diamond working portion 4 operate with force on the maxillary bone M, remove a lot of material in a few steps and, at the same time, facilitate the discharge of the burred bone towards the outside of the patient’s mouth.

[0052] Usefully, the cylindrical diamond working portion 3 comprises: at least a first cylindrical stretch 7, associated with the proximal non-working portion 2 and having a first working diameter DLI; at least a second cylindrical stretch 8, associated with the conical diamond working portion 4 and having a second working diameter DLI smaller than the first working diameter DLI; at least one tapered connecting stretch 9, arranged between the first cylindrical stretch 7 and the second cylindrical stretch 8.

[0053] The first working diameter DLI and the second working diameter DLI of the dental burr 1 are determined based on the dimensions of the implant I to be installed.

[0054] In this context, the difference between the first working diameter DLI and the second working diameter DL2 allows the dental burr 1, and the relevant channel it cuts in the maxillary bone M, to be adapted to the shape of the implant I, which usually has a diameter that increases gradually as it displaces from its apical portion IA to its coronal portion Ic.

[0055] Advantageously, the second working diameter DL2 is smaller than the first working diameter DLI by a difference of between 0.05 mm and 0.25 mm, better still of between 0.1 mm and 0.2 mm, preferably equal to 0.15 mm.

[0056] In the particular embodiment shown in the figures, the implant I has a coronal portion with a diameter of 4 mm, the first working diameter DLI is of between 3 and 3.8 mm, better still of between 3.2 mm and 3.6 mm, preferably equal to 3.4 mm, while the second working diameter DL2 is of between 2.9 and 3.6 mm, better still of between 3.1 mm and 3.4 mm, preferably equal to 3.25 mm.

[0057] Alternative embodiments cannot, however, be ruled out wherein the dental burr 1 has smaller working diameters DLI, DL2, SO as to be adapted to install thinner implants I, or larger working diameters DLI, DL2, to install wider implants I.

[0058] Embodiments cannot be ruled out wherein the cylindrical diamond working portion 3 may not comprise the cylindrical stretches 7, 8 having different diameters and connected to each other, but consists of a single cylindrical segment with a constant diameter along its entire length.

[0059] The cylindrical diamond working portion 3 defines the useful length L of the dental burr 1, meant as the maximum distance from the non-diamond working lanceolate tip 5.

[0060] In the exemplary embodiment shown in the figures, the useful length L of the dental burr 1 is of between 27 and 39 mm, better still of between 30 mm and 36 mm, preferably equal to 33 mm.

[0061] Advantageously, the dental burr 1 comprises reference markings 10 arranged on the cylindrical diamond working portion 3.

[0062] The reference markings 10 guide dentists during the use of the dental burr 1, allowing them to establish the depth of the dental burr in the maxillary bone M and to remove a precise amount of bone which is proportionate to the specific requirements of the operation and, in particular, based on the length of the implant I.

[0063] Usefully, each reference marking 10 comprises a plurality of depth notches 11 arranged at a predetermined distance from the end of the non-diamond working lanceolate tip 5 (i.e., the point of the dental burr 1 that is located furthest from the proximal non- working portion 2).

[0064] In accordance with the preferred embodiment shown in the figures, each reference marking 10 comprises two depth notches 11, which correspond to the edges of the reference marking 10 arranged circumferentially along the entire cylindrical diamond working portion 3. By providing four reference markings lu, it is possible to identify eight edges and eight depth notches 11 arranged at different distances, corresponding to eight reference lengths LI, L2, L3, L4, L5, L6, L7, L8 that are different from each other.

[0065] In this way, the dentist can clearly: work on a stretch of the maxillary bone M corresponding to a specific reference length LI, L2, L3, L4, L5, L6, L7, L8 decided on the basis of the implant I to be installed; or vice versa having a series of implants I of different lengths available, choose the implant I of the appropriate length for the depth reached by the dental burr 1.

[0066] In the particular embodiment of the burr shown in the figures, the reference lengths LI, L2, L3, L4, L5, L6, L7, L8 are as follows: reference length LI: 19 mm; reference length L2: 19.5 mm; reference length L3: 21 mm; reference length L4: 23 mm; reference length L5: 25 mm; reference length L6: 27 mm; reference length L7: 29 mm; reference length L8: 31 mm.

[0067] Alternative embodiments of the present invention cannot however be ruled out wherein, for example, a different number of reference markings 10 are provided, and / or reference markings 10 and depth notches 11 of different types are provided, and / or are positioned so as to define reference lengths LI, L2, L3, L4, L5, L6, L7, L8 of different dimensions.

[0068] The conical diamond working portion 4 extends between a stretch with a larger diameter DM and a stretch with a smaller diameter Dm.

[0069] Usefully, the larger diameter DM coincides with the second working diameter DL2, so that the conical diamond working portion 4 represents a continuation of the second cylindrical stretch 8 without steps or shoulders (i.e., without jumps or discontinuities). In the embodiment shown in the figures given as an example, the larger diameter DM is of between 2.9 and 3.6 mm, preferably of between 3.1 mm and 3.4 mm, and better still 3.25 mm, while the smaller diameter Dmis of between 1.8 and 2.2 mm, preferably of between 1.9 mm and 2.1 mm, and better still 2.0 mm; the conical diamond working portion 4 also has a conicity, i.e. an inclination with respect to the axis of rotation A, which is of between 4° and 9°, preferably of between 4.5° and 7°, and preferably equal to 5°.

[0070] Moving on to describe the non-diamond working lanceolate tip 5, it should first be specified that, in this disclosure, the term “lanceolate tip” refers to burrs with a very pointed apical end, e.g. with a pyramidal shape (or slightly curved but still similar to a pyramid), with a square or triangular base or of another shape (e.g. star-shaped), in which the angle at the tip, i.e. the angle at the vertex of the faces of the pyramid, is smaller than 50°.

[0071] This special expedient allows the dental burr 1 to engage stably and securely on the surface M2, even if it is inclined with respect to the axis of rotation A, preventing unwanted slipping and / or vibration of the dental burr 1, thus increasing the dentist’s control and the safety of the osteotomy surgery on the patient.

[0072] Furthermore, thanks to the shape of the non-diamond working lanceolate tip 5 and the simultaneous presence of the cylindrical diamond working portion 3 and of the conical diamond working portion 4, the dentist can correct the position of the dental burr 1 within the cavity C by making it slightly oscillate around the non-diamond working lanceolate tip 5, which serves as a fulcrum, thus ensuring correct positioning of the through hole Fl and, if necessary, removing any excess bone material in the proximity of the surface M2 that could hinder the subsequent screwing of the implant I; in other words, and as will be described in more detail below, the dental burr 1 according to the invention allows promoting the positioning of the implant I in the maxillary bone M at the correct depth and angle. With particular reference to the embodiment of the dental burr 1 shown in the figures given as an example, the non-diamond working lanceolate tip 5 is at least partly pyramid-shaped with a triangular base and has three side faces 12 of at least partly triangular shape which have an angle at the vertex a smaller than 50°. Usefully, the angle at the vertex a is smaller than 40°, preferably of between 30° and 35°, and preferably equal to 33.32°.

[0073] The side faces 12 which are arranged staggered at 120° to each other around the axis of rotation A, are inclined with respect to the axis of rotation itself by an angle of incidence 0 e.g. of between 8° and 20°, better still of between 9° and 15°, preferably equal to 10°.

[0074] Furthermore, between two adjacent side faces 12, a cutting edge 13 is defined which is inclined with respect to the axis of rotation A by a cutting angle of between 16° and 23°, preferably of between 18° and 21°, preferably equal to 19.33°.

[0075] The non-diamond working lanceolate tip 5 is shaped so as to define a maximum working diameter DLM, i.e. the maximum diameter of a hole that it is capable of hollowing out in the maxillary bone M.

[0076] Advantageously, the maximum working diameter DLM is smaller than the larger diameter DM of the conical diamond working portion 4; this means that when the dental burr 1 is set in axial forward movement and penetrates the maxillary bone M, the corresponding hole is initially produced by the non-diamond working lanceolate tip 5 and then enlarged by the upcoming conical diamond working portion 4.

[0077] Usefully, the maximum working diameter DLM coincides with the smaller diameter Dmof the conical diamond working portion 4.

[0078] In the embodiment shown in the figures given as an example, the maximum working diameter DLM is of between 1.8 and 2.2 mm, better still of between 1.9 mm and 2.1 mm, preferably equal to 2.0 mm.

[0079] Advantageously, the non-diamond working lanceolate tip 5 is associated with the conical diamond working portion 4 by interposition of a discharge portion 14 having a smaller diameter than the maximum working diameter DLM of the non- diamond working lanceolate tip 5.

[0080] The discharge portion 14, in actual facts, consists of a stretch of the dental burr 1 with a reduced diameter in which part of the maxillary bone M burred by the dental burr 1 is collected; this improves me operation of the dental burr 1, in particular preventing the material burred by the non-diamond working lanceolate tip 5 from becoming stuck between the conical diamond working portion 4 and the maxillary bone M not yet burred, thus hindering the rotation of the dental burr 1.

[0081] Usefully, the discharge portion 14 has a conical conformation and increasing diameter along the direction of departure from the conical diamond working portion 4; this particular conformation facilitates the outflow of the burred bone material.

[0082] The operation of the present invention is as follows.

[0083] After adequately preparing the patient for surgery, the dentist mounts the dental burr 1 on the tool for setting in rotation S, sets it in rotation and inserts it into the patient’s mouth in the proximity of the maxillary bone crest Ml (Figure 5).

[0084] At this point, through an axial movement, the dental burr 1 is pushed into the maxillary bone M, which is first hollowed out by the non-diamond working lanceolate tip 5 and then by the conical diamond working portion 4, making a through hole Fl in the maxillary bone crest Ml, passing through the cavity C up to the surface M2 and starting to make the blind hole F2 thereon (Figure 6).

[0085] During this phase of the surgery, thanks to its special conformation, the non- diamond working lanceolate tip 5 is able to scratch and dig into the surface M2 easily, without slipping or twisting, even if the surface itself is very inclined with respect to the axis of rotation A.

[0086] If the dental burr 1 has not been inserted at a suitable angle, the dentist can correct the position thereof inside the maxillary bone M by keeping the non-diamond working lanceolate tip 5 in contact with the surface M2 and making the dental burr 1 oscillate using the non-diamond working lanceolate tip 5 as a fulcrum, so as to bring the conical diamond working portion 4 closer to the surface M2 and enlarge the through hole Fl (Figure 7) at the same time.

[0087] Once this operation is complete, the dentist makes the dental burr 1 penetrate axially into the maxillary bone M to finish burring the blind hole F2 on the surface M2 to the desired depth (Figure 8). Figure 9 shows the blind hole F2 and tne rnrough hole Fl once the dental burr 1 has been removed from the patient.

[0088] Once the osteotomy has been prepared, the implant I can be arranged through the through hole Fl and screwed into the blind hole F2 (Figure 10). It has in practice been ascertained that the described invention achieves the intended objects.

[0089] In this regard, it should be pointed out that the present invention allows the implant surgery to be completed using a single burr, which simplifies surgical procedures and reduces treatment times and risks for the dentist and patient, particularly those of contamination.

Claims

CLAHVIS1) Dental burr (1) characterized by the fact that it comprises: at least one proximal non-working portion (2) connectable to a tool for setting in rotation (S); at least one cylindrical diamond working portion (3) associated with said proximal non- working portion (2); at least one conical diamond working portion (4) associated with said cylindrical diamond working portion (3) and having a decreasing diameter along the direction of departure from said cylindrical diamond working portion (3); at least one non-diamond working lanceolate tip (5) associated with said conical diamond working portion (4).2) Dental burr (1) according to claim 1, characterized by the fact that said nondiamond working lanceolate tip (5) is at least partly pyramid- shaped with a triangular base and has three side faces (12) of at least partly triangular shape which have an angle at the vertex (a) smaller than 50°.3) Dental burr (1) according to one or more of the preceding claims, characterized by the fact that said angle at the vertex (a) is smaller than 40°.4) Dental burr (1) according to one or more of the preceding claims, characterized by the fact that said angle at the vertex (a) is of between 30° and35°.5) Dental burr (1) according to one or more of the preceding claims, characterized by the fact that said non-diamond working lanceolate tip (5) is associated with said conical diamond working portion (4) by the interposition of a discharge portion (14) having a smaller diameter than a maximum working diameter (DLM) of said non-diamond working lanceolate tip (5).6) Dental burr (1) according to one or more of the preceding claims, characterized by the fact that said discharge portion (14) has a conical conformation and increasing diameter along the direction of departure from said conical diamond working portion (4).7) Dental burr (1) according to one or more of the preceding claims, characterized by the fact that at least one of said cylindrical diamond working portion (3) and said conical diamond working portion (4) is coated with a diamond layer having a grit between D126 and D251.8) Dental burr (1) according to one or more of the preceding claims, characterized by the fact that said cylindrical diamond working portion (3) comprises: at least a first cylindrical stretch (7) associated with said proximal nonworking portion (2) and having a first working diameter (DLI); at least a second cylindrical stretch (8) associated with said conical diamond working portion (4) and having a second working diameter (DLI) smaller than said first working diameter (DLI); at least one tapered connecting stretch (9) arranged between said first cylindrical stretch (7) and said second cylindrical stretch (8).9) Dental burr (1) according to one or more of the preceding claims, characterized by the fact that said second working diameter (DLI) is smaller than said first working diameter (DLI) by a difference of between 0.05 mm and 0.25 mm.10) Dental burr (1) according to one or more of the preceding claims, characterized by the fact that it comprises reference markings (10) arranged on said cylindrical diamond working portion (3).

Images