Technical Field

[0001] The present invention relates to a dental implant system, comprising a dental implant having a frustoconical cavity, an abutment having an abutment post to be definitively retained in the frustoconical implant cavity and an abutment head for supporting a dental crown, a transfer abutment having a transfer post intended to be inserted into the frustoconical implant cavity before impression taking, and a transfer head identical to the abutment head, and an implant analog. For convenience in the following the transfer abutment will be called simply transfer. The transfer is an abutment that is inserted into a dental implant for impression taking made with a suitable deformable material without the use of a definitive abutment. In fact, by using the latter, there is the risk that the impression is not easily removable from the patient's mouth due to the shape adherence of the definitive abutment.

[0002] The invention relates in particular to a dental implant that has a through seat for the abutment pin.

Background Art

[0003] US 6,290,500 describes a system and a dental implant method in which a transfer is present. The transfer has a substantially cylindrical pin portion with a longitudinal axis provided with a longitudinally extending slot so that the pin portion can be removably received in the hole of an implant having a retention taper. In fact, the slot allows the pin portion to adhere elastically to the walls of the implant hole only for impression taking.

[0004] It has been noted that a portion of such a pin does not maintain the abutment in a stable condition, and this can lead to an imprecise impression taking.

[0005] Furthermore, the mentioned transfer does not have a means of identifying its circum ferential position inside the plant.

[0006] WO 2017/137588 relates to an abutment suitable to be attached to a dental implant.

The abutment has a main body comprising a tapered portion, and a prism shaped at tachment portion for attaching the abutment to the dental implant. The abutment at tachment portion comprises a plurality of projections for frictional coupling with a cor responding inner portion of the dental implant, and the abutment tapered portion mates with a facing tapered portion of the dental implant. The contact between the abutment attachment portion and the inner portion of the dental implant mainly occurs by the projections that are elastically and plastically deformable.

[0007] The document WO 2017/137588 deals with the problem of obtaining the easy removal of an abutment from an implant that is particularly critical in impression taking.

[0008] The present invention aims, on the one hand, to provide a dental implant system that allows a simple and easy execution of the operations that the dentist must perform before the definitive abutment is installed, in particular in relation to the transfer.

[0009] On the other hand, the invention intends to provide a dental implant that has features of reduced dimensions, especially in length, and shape features that can allow it to be easily integrated into a dental arch.

Summary of the invention

[0010] An object of the present invention is to provide a dental implant system in which a transfer on one hand is received stably in the implant hole for a precise impression taking, and on the other hand allows an easy and comfortable removal of the im pression after hardening of the deformable material with which it is taken.

[0011] Another object of the present invention is to provide a dental implant that has a

through seat for the abutment, in other words a dental implant that has an internal cavity open from the apical end to the inlet end for the abutment.

[0012] Therefore, the invention provides a dental implant system, as defined in the main claim and in dependent claims.

[0013] Advantageously, the dental implant in which the transfer according to the present invention is used, is of a screw type, but could also be different, such as for example a plateau type. Its frustoconical cavity is a longitudinal through hole for the insertion of the abutment complete with dental crown. The frustoconical cavity can have apically, i.e. on the side opposite to the insertion side of the abutment, a prismatic end space, for example hexagonal, communicating with the outside. This allows a stable, not rotatable positioning of both the transfer and the abutment in the implant. Alter natively, the prismatic end space can be round, i.e. a longitudinal continuation of the dental implant frustoconical cavity.

[0014] Moreover, since the frustoconical cavity is a through hole, the dimensions of the implant are reduced.

[0015] The frustoconical cavity could have a very small conicity, for example less than 4°, which is normally called conometric. The feature for which the frustoconical cavity is a through hole is particularly advantageous because the abutment can exploit the entire length of the dental implant for its installation. Moreover, the fact that the apical end of the dental implant is hollow allows the insertion of the bone formation inside it for a better integration and stabilization of the dental implant in the dental arch.

Brief Description of Drawings

[0016] Further features and advantages of the present invention will become most evident from the description of embodiments of a dental implant system, illustrated by way of an example in the accompanying drawings in which:

[0017] - Figure 1 is a central longitudinal section of a dental implant according to the present invention;

[0018] - Figure 2 is a schematic side view of a transfer according to the present invention;

[0019] - Figure 3 is a side view of the transfer of Figure 2 inserted in a model implant

analog, represented in cross-section, that was obtained from an impression, on the transfer being a tooth crown represented with a dashed line;

[0020] - Figure 4 is a schematic side view of an abutment to be inserted stably in the implant in Figure 1 ;

[0021] Figure 5 is a partially cross-sectioned side view of the abutment in Figure 4 complete with a dental crown shown with a dashed line and inserted in the implant in Figure 1 ;

[0022] - Figure 6 is a central longitudinal section of a first variant of the dental implant according to the present invention;

[0023] - Figure 7 is a schematic side view of a first transfer variant according to the present invention;

[0024] - Figure 8 is a central longitudinal section of a second variant of the dental implant according to the present invention;

[0025] - Figure 9 is a central longitudinal section of a third variant of the dental implant according to the present invention;

[0026] - Figure 10 is a side view of a fourth variant of the dental implant according to the present invention and of a cap shown exploded with respect to the implant;

[0027] - Figure 11 is an assembled central longitudinal cross-section of the fourth variant of the dental implant with the cap; and

[0028] - Figure 12 is a central longitudinal section of a fifth variant of the dental implant according to the present invention.

[0029] Description of Embodiments of the Invention

[0030] Reference is initially made to Figure 1 which is a central longitudinal section of a dental implant according to the present invention. The dental implant, which is indicated generally as 1, is represented as of the screw type, but in the following it is shown that it could also be different, such as of a plateau type. Designated as 2 is a frustoconical cavity which is a longitudinal through hole for the insertion of an abutment complete with a dental crown. The frustoconical cavity 2 has, on a side opposite to the insertion side of the abutment, that is to say in its base or apical end, a non-round end space 3, for example of hexagonal prismatic shape. Thanks to the fact that the frustoconical cavity 2 is a longitudinal through hole, the dimensions of the implant 1 are reduced, even by 0.3-2 mm, compared to a conventional implant without a through cavity. [0031] Figure 2 is a schematic side view of a transfer according to the present invention.

Traditionally, the transfer, indicated generally as 4, has a transfer post 5 terminating in- feriorly with a non-round end conforming to that of the end space 3, for example a hexagonal prismatic end 6, such as to be inserted in the end hexagonal prismatic space

3 of the frustoconical cavity 2. Furthermore, the transfer 4 has a transfer head 7 intended to support a dental crown. The transfer head 7 is shown as having a frus toconical shape tapered on the side opposite to the transfer post 5. As is known, the transfer head 7 has a lightening 8 or the like to indicate the orientation of the transfer 4. According to the present invention, the transfer post 5 has a first frustoconical su perficial retaining portion 9, bordering at the top with the transfer head 7, and a second frustoconical surface portion 10 with a taper lower than that of the first frustoconical surface portion 9. Preferably, the extension of the first frustoconical surface retaining portion 9 is a quarter of the extension of the second frustoconical surface portion 10. Such a configuration of the transfer 4, that is double-conical, is useful for impression taking on the implant 1 in Figure 1. In fact, the first frustoconical retaining portion 9 has the same conicity as the frustoconical cavity 2 of the implant 1. When the transfer

4 is inserted with the transfer post 5 in the frustoconical cavity 2 of the implant 1, the first frustoconical surface retaining portion 9 remains adherent due to friction in the right extent with the surface of the frustoconical cavity 2, while its hexagonal prismatic end 6 is locked to the rotation in the end hexagonal prismatic space 3 of the frus toconical cavity 2. The right measure of adherence indicated above allows the removal of the impression without the risk that the transfer 4 remains attached to the implant 1 instead of being integral with the deformable material used for impression taking.

[0032] As is known, the plaster cast is obtained on the impression, as shown schematically in Figure 3 that comprises in a side view the transfer 4 in Figure 1. The transfer 4 is inserted in an implant analog 11 embedded in the plaster cast 12 obtained on the im pression. The plaster cast 12 is shown in partial cross-section, while a dental crown 13 represented with a dashed line is made on the transfer 4. The dental crown 13 is made by the dental technician with known techniques and materials. The implant analog 11 has an outer surface 14 provided with undercuts 15 for retaining it inside the plaster cast 12 and an internal cavity 16 for receiving the transfer post 5. An upper portion 17 of the internal cavity 16 has a frustoconical shape with the same conicity as the frus toconical cavity 2 of the implant 1 to adhere to the first frustoconical- shaped retaining portion 9 of the transfer 4, while the rest of the internal cavity 16 is not in contact with the transfer post 5. Furthermore, the internal cavity 16 has a bottom 18, to receive the hexagonal prismatic end 6 of the transfer 4.

[0033] Once manufactured, the dental crown 13 can be placed on the abutment 19 shown in the schematic side view in Figure 4. [0034] Schematically, the abutment 19 is of the frustoconical type tapered towards both ends. Traditionally, the abutment 19 has an abutment post 20 terminating inferiorly with a non-round end, for example hexagonal prismatic 21, of the same shape and di mensions as the hexagonal prismatic end 6 of the transfer 4. The abutment 19 has an abutment head 22 intended for supporting a dental crown. The abutment head 22 is substantially identical to the transfer head 7. The abutment head 22 is shown as a frus toconical shape tapered on the side opposite to the abutment post 20, but could be different as well as the transfer head 7. As is known, the abutment head 22 has a lightning 8 or the like to indicate the orientation of the abutment 19. Conventionally, the abutment post 20 has a frustoconical surface to be stably retained by the surface of the frustoconical cavity 2 of the implant 1.

[0035] Reference is made to Figure 5, which is a partially cross-sectioned side view of the abutment 19 in Figure 4 complete with dental crown 13, that is shown by dashed line, and inserted in the implant 1 that is already installed in the patient's mouth. The dental crown 13 is cemented onto the abutment head 22. The insertion of the abutment 19, complete with dental crown 13, in the implant is performed with conventional techniques. The abutment post 20 is perfectly tightly connected to the frustoconical cavity 2 of the implant 1.

[0036] Reference should now be made to Figures 6 and 7 which show a central longitudinal cross-section of a first implant variant and a schematic side view of a first transfer variant, respectively, according to the present invention. A dental implant 100 is similar to that shown in Figure 1 but, unlike the one, it does not have the not round end space, in its frustoconical cavity 200, which is a longitudinal through hole for the insertion of the abutment complete with a dental crown. In fact, the frustoconical cavity 200 extends over the entire length of the implant. This variant shown in Figure 6 makes easier to fabricate the implant with respect to the implant 1 shown in Figure 1.

[0037] Figure 7 shows a first variant of transfer 400, having a transfer post 500 terminating inferiorly with a round end, unlike the transfer 4 in Figure 2. Like that, the transfer 400 has a transfer head 7 intended to support the dental crown, the transfer head 7 having a lightning 8 to indicate the orientation of the transfer 400. Unlike the transfer 4 of Figure 2, the transfer post 500 has a first frustoconical retaining surface portion 900, bordering at the top with the transfer head 7, having substantially double extension with respect to the first frustoconical retaining surface portion 9 in Figure 2, at the expense of the second frustoconical surface portion 101 of lower conicity. The increase in extension depends on the need to create an adequate friction tightness, since the hexagonal prismatic end present in the transfer 4 in Figure 2 is missing.

[0038] Reference should now be made to Figures 8 and 9 that show in central longitudinal cross-section a second and third variant of dental implant, respectively, according to the present invention. The second variant of dental plant in Figure 8 is of a screw type, and the third variant of dental plant in figure 9 is of a plateau or platform type. Both implants have a conometric or Morse cavity, i.e. with a conicity lower than 4°.

[0039] The second variant shown in Figure 8 and indicated with 30 has a conometric cavity 31 and the screw threads, indicated generically with 32, have a triangular cross-section.

[0040] The third variant shown in Figure 9 and indicated with 40 has a conometric cavity 41 and the platforms, indicated generically with 42, have a rectangular cross-section.

[0041] Reference should now be made to Figures 10 and 11 which are a side view and a central longitudinal cross-section, respectively, of a fourth variant 50 of the dental implant according to the present invention and of a frustoconical cap 60 shown exploded with respect to the implant and assembled, respectively. The frustoconical cap 60 can also be inserted into the cavities 200, 31, 41 of the respective implants 100, 30, 40.

[0042] As the third variant 40 shown in Figure 9, the fourth variant indicated as 50 has a conometric cavity 51 and the platforms, indicated generically as 52, have a rectangular cross-section. Furthermore, end platforms generally indicated as 53 are tapered toward implant opposite ends, that are the apical one 54 and the inlet one 55, along inclined tracts indicated generically as 56.

[0043] A fifth variant, analogously shown in Figure 12 and indicated as 70 has a conometric cavity 71 and the platforms, indicated generically as 72, have a rectangular cross- section terminating with a triangle.

[0044] In the four variants of dental implant 30, 40, 50, 70, traditional abutments, such as the one indicated as 19 in Figure 4 but deprived of the hexagonal end 21, can be inserted.

[0045] The frustoconical cap 60 also has a taper similar to that of the cavity 51 of the

implant 50 and is made of plastic material. It has a blind hole 61 centrally in its top for its grip by means of a suitable tool in the form of a corkscrew or reamer. The cap 60 is useful to keep the implant closed, already installed in the patient's mouth, before the final abutment is inserted so that the cavity 51 of the implant is not occupied by bone that could form and insert itself apically, i.e. from the bottom, inside the implant cavity, or by gingival tissue that could insert itself from the top inside the implant cavity.

[0046] It should be understood that the dental implant system according to the present

invention achieves the intended objects. Thanks to the fact that the cavity of the dental implant is a through hole, its length can be advantageously reduced. In fact, a conometric contact of only 2,5 mm is enough for giving stability to a connection between abutment and implant. This is particularly useful in cases where a so-called short implant is needed due to the reduced vertical bone size. [0047] Moreover, the dental implant system according to the present invention allows an easy impression taking in the mouth of the patient and its easy removal from it for the construction of the model and the manufacturing of the dental crown. This will be moved by the transfer and, then, fixed on the abutment for the permanent installation of this in the patient's implant.