ZYGOMATIC IMPLANT WITH PARTIALLY INTERRUPTED THREADED PORTION

Abstract

A utility model pertains to the field of dental treatment components and was developed with the objective of better installation conditions, greater mechanical stability and greater comfort during use, when compared to similar ones in the current state of the art. It includes: an implant consisting of elongated and cylindrical body; conical apical region coated by a screw thread and with at least three helical chambers and semi-spherical end; and a cervical region defined by a smooth cervical surface, the elongated and cylindrical body including at least one longitudinal strip having a substantially smooth surface, said smooth longitudinal strip being located in the zygomatic implant cervical portion; the connection between the screw threads and the smooth longitudinal strip is made by a transition curvature, and the smooth longitudinal strip is aligned with one of the flat sides of the internal area with hexagonal cross section of the implant prosthetic interface.

Claims

1. A zygomatic implant having a partially interrupted threaded portion, said implant being defined by: an elongated and cylindrical body provided with a double screw thread; a conical apical region having a surface provided with screw thread, the conical apical region comprising at least three helical chambers and a semi-spherical end; and a cervical region defined by a smooth cervical surface the edge of which being orthogonally attached to a perimeter and flat platform that delimits the opening interspace of a prosthetic interface provided with at least one internal area with a hexagonal cross section, wherein: the elongated and cylindrical body comprises at least one longitudinal strip having a substantially smooth surface, the smooth longitudinal strip being located in the zygomatic implant cervical portion; the connection between the screw threads and the smooth longitudinal strip being made by a transition curvature, and the smooth longitudinal strip being aligned with one of the flat sides of the implant prosthetic interface internal area with hexagonal cross section.

2. The zygomatic implant according to claim 1, wherein the smooth longitudinal strip starts from the smooth cervical surface and extends to the zygomatic implant median region.

3. The zygomatic implant according to claim 1, wherein the smooth longitudinal strip extends and goes beyond the zygomatic implant median region.

4. The zygomatic implant according to claim 1, wherein the prosthetic interface comprises: a fustoconical region having a progressively reduced diameter from the platform towards the implant apex; a hexagonal region; and a cylindrical region provided with an internal thread.

5. The zygomatic implant according to claim 1, wherein the prosthetic interface comprises one of the following interfaces: morse taper, external hexagon or internal hexagon.

6. The zygomatic implant according to claim 1, wherein the smooth longitudinal strip surface is recessed at a distance (r) in relation to the perimeter of the screw threads.

7. The zygomatic implant according to claim 1, wherein it comprises at least one marker means arranged in the zygomatic implant, the half marker indicating the position of the flat side of the internal area with hexagonal cross section of the implant prosthetic interface corresponding to the positioning of the smooth longitudinal strip.

8. The zygomatic implant according to claim 7, wherein the half marker is located in one of the following zygomatic implant locations: prosthetic interface platform, smooth cervical surface, or fustoconical region.

9. The zygomatic implant according to claim 7, wherein the half marker comprises at least one of a color marker, an inscription, a protrusion or a recess.

10. The zygomatic implant according to claim 1, wherein it comprises a screw thread angle (α.sub.1) greater than the zygomatic implant apical region core angle (α.sub.2), while the screw thread is parallel to the cylindrical body core where it is located.

11. The zygomatic implant according to claim 1, wherein the apical region screw thread comprises substantially trapezoidal geometry having various tapered crest unique screw threads, and the cylindrical body screw thread comprises trapezoidal geometry.

12. The zygomatic implant according to claim 8, wherein the half marker comprises at least one of a color marker, an inscription, a protrusion or a recess.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present utility model will be described in more detail below based on an example embodiment represented in the appended figures, which show:

[0028] FIGS. 1.1 and 1.2—representations of the internal structures of the face showing the zygomatic bone, the maxillary sinuses' cavities and the maxillary bone in which a multiple prosthesis (protocol; see FIG. 1.1) is properly installed with the aid of current state of the art zygomatic implants;

[0029] FIG. 2—an isolated view of a state of the art zygomatic implant, which is provided with a screw thread throughout its entire body;

[0030] FIG. 3—a perspective view of another current state of the art implant, which has the medial region of its body smooth and devoid of screw threads;

[0031] FIG. 4—another perspective view of a current state of the art implant, provided with a screw thread only in its apical portion and with the rest of its body (in the medial and cervical regions) completely smooth and devoid of screw thread;

[0032] FIG. 5—a lateral view of another current state of the art implant, which shows a longitudinal interruption in its body's apical region, delimited by tapered and cutting threads;

[0033] FIG. 6—a perspective view of a preferred embodiment of the zygomatic implant with partially interrupted threaded portion—object of the present utility model;

[0034] FIG. 7—an enlarged and partially sectioned detail of the zygomatic implant cervical portion shown in FIG. 6, allowing to observe the alignment between the internal hexagon of the coupling interface and the region with partially interrupted screw thread;

[0035] FIG. 8—shows a lateral view of the zygomatic implant body's cervical region of FIG. 6 in which the partially interrupted screw thread is located, in total alignment and projection in relation to a top view that allows to observe the part cervical end internal portion;

[0036] FIG. 9—a lateral view of the object of the present utility model, with enlarged details of the screw threads existing in its apical and cervical portions,

[0037] FIG. 10.1—a bottom view showing the apical end of the zygomatic implant object of the present utility model;

[0038] FIG. 10.2—a lateral view of the apical portion of the zygomatic implant shown in FIG. 6, emphasizing the angle difference between the implant core and its thread;

[0039] FIG. 11—an enlarged detail view of the now presented zygomatic implant cervical end;

[0040] FIG. 12—a lateral view in enlarged detail of the present utility model zygomatic implant core, allowing to observe its smooth region forming as a result of the partially interrupted screw thread;

[0041] FIGS. 13 and 14—show cross sections of the present utility model zygomatic implant (FIG. 13) and the WO2011/063958 current state of the art implant (FIG. 14), respectively, allowing to compare the transition difference between the smooth and threaded regions of the two versions; and

[0042] FIG. 15—shows an enlarged detail of the cervical portion of the zygomatic implant object of this utility model application.

DETAILED DESCRIPTION OF THE UTILITY MODEL

[0043] The object of the present utility model will be described and explained in more detail based on the appended drawings, which are merely exemplary and not limiting, since adaptations and modifications can be made without changing the scope of the claimed protection.

[0044] As already mentioned, FIGS. 1 to 5 show current state of the art zygomatic implants, which are presented in the section “Related art”, at the beginning of the present specification.

[0045] FIG. 6 illustrates a preferred embodiment of the present utility model zygomatic implant 10, which is defined by: [0046] an elongated and cylindrical body 11; [0047] a conical apical region 12 coated by a screw thread 121, said conical apical region 12 being provided with at least three helical chambers 13 and a semi-spherical end 14; and [0048] a cervical end defined by a smooth surface 15 finishing in perimeter and flat platform 16 that adds the straight interface feature to the implant.

[0049] The elongated and cylindrical body 11 is also provided with screw thread 111, except in a longitudinal strip 112 which has a substantially smooth surface—that is, through which no unique screw thread 111 pass, since they are interrupted on that region periphery. It should be noted that in the illustrative drawings accompanying the present application, the preferred embodiment of the zygomatic implant 10 was represented containing only a smooth longitudinal strip 112, but the PHOSITAs will realize that it will obviously be possible to use at least one more smooth strip on the body, in a symmetrical position to the strip 112, as long as the final objective of solving the drawbacks of the current state of the art is maintained.

[0050] In this respect, it should be clarified that the screw threads 111—which will be double, showing a trapezoidal profile—are smoothly interrupted, that is, through a transition curvature 113, so that there are no cutting corners and cutting edges between the smooth longitudinal strip 112 and the portion provided with a screw thread 111, as can be seen in appended FIGS. 13 and 15. Furthermore, preferably this longitudinal strip 112 radius is 2.5 mm with axis biased in relation to the implant 10 axis, which keeps the longitudinal strip 112 surface recessed at a distance r in relation to the screw threads 111 perimeter and therefore, further away from the patient face internal tissues.

[0051] The performance of a comparative analysis between FIGS. 13 and 14 allows to clearly observe how the interruption of the state of the art screw threads generates piercing and cutting tips (RAC), while the interruption of the present proposal screw threads is done gradually and, therefore, without the presence of sharp and/or blunt vertexes. Furthermore, it is possible to observe that the form of interruption of the state of the art screw threads maintains practically the same perimeter area as the rest of the implant, whereas in the zygomatic implant now presented, this area is significantly reduced and recessed, thereby distancing the smooth longitudinal strip 112 from the soft tissues of the face of the user as explained above.

[0052] It is important to highlight that, in the example drawings accompanying this specification, said smooth longitudinal strip 112 starts right after the implant 10 smooth cervical surface 15. However, the PHOSITAs will understand that such smooth longitudinal strip 112 may extend in length and go beyond the implant 10 median region, or is located only in the cervical portion thereof, but away from the smooth cervical surface 15. Such positions do not interfere with the implant 10 suitable anchoring conditions, since its effective interaction with the patient bone regions will already have been guaranteed by the conical apical region 12 screw threads 121 and the cylindrical body 11 initial unique screw thread 111 contiguous to the apical region 12.

[0053] Said zygomatic implant 10 end smooth cervical surface 15 ends on a perimeter and preferably orthogonal to its surface platform 16. Such perimeter platform 16 delimits the prosthetic interface opening interspace, which has a longitudinal axis coinciding with the implant axial axis, according to the drawing of appended FIGS. 7 and 15. From the platform 16 towards the apical region, such prosthetic interface is defined by: a fustoconical region 17 whose diameter is progressively reduced from the platform 16 towards the implant apex; a hexagonal region 18; and a cylindrical region provided with an internal thread 19 for coupling and fixation the suitable prosthetic component (not shown).

[0054] It should be clarified that the preferred prosthetic interface described above is exemplary and can be replaced by any other type of interface known in the current state of the art, such as, for example, morse taper, external hexagon or internal hexagon, without escaping the herein claimed protection scope.

[0055] FIGS. 7 and 8 show that the implant 10 longitudinal strip 112 is aligned/indexed to one of the straight sides of the prosthetic interface hexagonal region 18, in order to allow the installer, at the end of the installation, to place the implant in a way as to leave the longitudinal strip 112 devoid of screw thread turned to the patient vestibular, in order to prevent inconveniences and discomforts previously described and, consequently, to improve use in relation to similar ones known in the current state of the art. As is known, with the use in current state of the art zygomatic implants, the user is able to feel the part screw threads upon any pressure applied to his face, which can cause discomfort, irritation and bad impression. In the case of implants having a cutting interruption in the screw thread, such as the one disclosed in document WO2011/063958 (whose cross section is shown in the appended FIG. 14), there is an aggravation that the blunt edges of the screw threads—which are formed at the interruption location—can cause injuries to the internal area of the face section that covers the maxillary sinus region during possible more intense external pressures. Therefore, the configuration presented herein aims to ensure that, after implant installing, the user is not at risk of internal injuries or feels discomfort during any pressure applied to his face. Additionally, with the configuration disclosed herein, a recess r is created on the implant surface 10 which will be facing the vestibular of the user, which keeps it in a “deeper” position when compared to conventional implants—and, consequently, inaccessible to softer pressures on the face.

[0056] The identification of the face of the hexagonal region 18 which is indexed to the smooth longitudinal strip 112 can be done by associating the already installed implant visualization (remembering that the zygomatic implants' installation process foresees the previous opening of a interspace for visualizing the maxillary sinus) with the use of a hexagonal installation driver (not shown) provided with marker elements in positions corresponding to the straight sides by simply positioning the marker corresponding to the hexagon 18 side which is aligned/indexed to the implant 10 smooth longitudinal strip 112 for the patient vestibular.

[0057] Optionally the hexagonal region 18 side which is indexed with the smooth longitudinal strip 112 can be identified on the implant 10 itself by means of any marker which, for example, can be a color marking, an inscription, a protrusion or a recess, and such a half marker can be located on the platform 16, on the smooth cervical surface 15, or in the fustoconical region 17 of the prosthetic interface.

[0058] The zygomatic implant 10 it can be produced in any diameter suitable to the part use function, being that, in the preferred embodiment presented herein, this diameter measures 4.0 mm. Additionally, its external screw thread 111, which has two entrances on the right next to the smooth cervical surface 15, preferably has a trapezoidal profile as can be seen in the appended FIG. 9 (that is, it does not have a cutting feature), and in the cylindrical body portion 11 the unique screw thread 111 height h1 preferably will be of 0.20 mm. The apical region 12 screw thread 121 will also have substantially trapezoidal geometry (also known as a reverse Buttress thread), and may have some unique screw threads with a more tapered crest than the others, as shown in the enlarged detail of FIG. 9, in order to better penetrate the bone during installation.

[0059] As previously mentioned, the apical region 12 has a substantially tapered profile, showing a semi-spherical end 14 and three helical chambers 13 equally distributed in its perimeter (see FIG. 10.1). Additionally, this apical region 12 screw thread 121 has a progressive increase in depth or height h2—which preferably will reach a maximum value of 0.4 mm—in the cervical direction.

[0060] Furthermore, in the appended FIG. 10.2 it is possible to notice that the screw thread 121 angle α.sub.1 is more pronounced than the implant core angle α.sub.2 in the apical region 12, this forming being intended to assist in the insertion and interaction of the part with the zygomatic bone. Therefore, the combination of conical apical profile with semi-spherical end 14, helical chambers 13 and progressive increase in the screw thread 121 depth h2 contribute to the promotion of appropriate apical anchorage and, consequently, to the implant primary stability.

[0061] Due to the fact that it is an implant for fixation on the zygomatic bone, it can be manufactured in a wide range of lengths, for example, 30.0/35.0/37.5/40.0/42.5/45.0/47.5/50.0/52.5 and 55.0 mm, preferably in Pure Titanium Grade 4 (according to ASTM F67 Standard “Unalloyed Titanium, for Surgical Implant Applications”) and, alternatively, using other manufacturing materials such as Zirconia or biocompatible polymeric materials. Additionally, the implant 10 may optionally present differentiated geometry in the semi-spherical end 14 central region 141 according to the example shown in FIG. 10.2, to allow the part suitable coupling to the packaging that will contain it—it should be noted that in the preferred embodiment illustrated in the indicated drawing, the central region 141 it is flat, but it can present other features according to the demand of the packaging to be used.

[0062] The body 11 smooth longitudinal strip 112 should, in the preferred embodiment herein presented, be initiated at a distance d1 of 1.60 mm and end at a distance d2 between 16.0 and 16.5 mm from the implant 10 platform 16, according to the appended FIG. 12 (which shows only the body 11 core, without the screw threads 111). The screw thread 111, complementing the cervical region, must end at a distance d3 of preferably 2.0 mm from the platform 16, with screw thread pitch P around 0.65 mm (see FIG. 9).

[0063] It is important to note that it will eventually be necessary to perform an additional movement in the torque or counter torque direction in order to position said smooth longitudinal strip 112 in the desired position—that is, facing the patient vestibular position. Considering that the most unfavorable positioning would occur when the point O shown in the section of FIG. 13 was facing toward the vestibular at the end of the installation, in the worst case it would be necessary to exercise a complementary half-turn movement to properly position the longitudinal strip 112 for the patient vestibular.

[0064] Therefore, using the preferential value of 0.65 mm for the screw thread pitch P, and since said implant will preferably be produced with a double screw thread, at each 360 degree rotation of the implant the lead will be 1.30 mm. Thus, in the worst case, at the end of the installation it will be necessary to exert a half rotation complementary torque or counter torque, resulting, in the now considered example, in a maximum complementary displacement of 0.65 mm. Therefore, the maximum displacement value required for positioning the longitudinal strip 112 in the patient vestibular position corresponds to half of the implant lead.

[0065] The manufacturing of the implant 10 object of the present utility model—which consists of the operations of (i) raw material dimensional transformation, (ii) machining, (iii) cleaning and (iv) packaging—demands the use of a lateral milling cutter (not shown) to ensure geometry in the longitudinal strip 112 devoid of screw threads, and this tool should be able to repeat a transition profile in curve 113 between the longitudinal strip 112 and the unique screw threads 111 as shown in FIG. 13.

[0066] For the use of the zygomatic implant 10, after properly preparing the installation site—which includes opening an interspace that allows the visualization of the maxillary sinus and, consequently, the implant itself to be installed—the operator must remove the implant from its packaging with the help of torque driver that is coupled to its prosthetic interface, an action that will automatically position one of the marking elements of the driver in a position corresponding to that of the hexagonal region 18 side which is aligned with the smooth longitudinal strip 112. Next, the implant is positioned 10 in the previously formed orifice with the aid of suitable drills, initiating the torque application to promote the implant insertion.

[0067] At this point, it is important to clarify that during the entire implant installation, it will be necessary to rotate it, even when the part with partially interrupted screw thread is inserted into the maxillary bone. This is due to the existence of the screw thread 111 in the region posterior to that in which the smooth longitudinal strip 112 is located (note that with the use of implants known in the current state of the art, the portion devoid of screw thread is located throughout the implant perimeter, so that for its installation it is enough for the operator to just slide this area through the orifice already formed in the bone). The zygomatic implant 10 external forming herein presented ensures that it remains aligned with the installation axial axis during the entire procedure, therefore without the possibility of unwanted misalignments—which facilitates the operation, in addition to guaranteeing the perfect positioning for placement of the planned prosthesis.

[0068] At the end of the installation—that is, after the implant 10 apical end is attached to the zygomatic bone and its entire body has already been inserted into the patient maxilla until the platform 16 faces the alveolar ridge—the operator must position the implant with a smooth longitudinal strip 112 facing the vestibular, which is done through the joint visualization of the implant 10 position with the position of the existing visual marker on the installation driver—that is, the implant 10 is slightly further screwed clockwise or counterclockwise until the suitable marker on the installation driver points to the patient vestibular, thereby making it so that the smooth longitudinal strip 112 also faces the vestibular. After this process is finished, the chosen prosthetic component and, subsequently, the prosthesis can be simply attached to complete the patient maxillary dental rehabilitation procedure.

[0069] Having described a preferred embodiment example, it should be understood that the scope of the present invention covers other possible variations and is limited only by the content of the appended claims, including possible equivalents thereof.