Patent Publication Number: US-2023140136-A1

Title: Dental implant

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Italian Patent Application No. 102021000027647, filed on Oct. 28, 2021, the entire contents of which are hereby incorporated in its entirety by reference 
     FIELD OF THE INVENTION 
     The present invention relates to an endosseous dental implant for anchoring dental prostheses, such as crowns, artificial teeth, and tooth bridges, in the maxillary or mandibular bone. 
     BACKGROUND OF THE INVENTION 
     In the field of dental implants, endosseous dental implants are widespread. These implants are designed to simulate how a natural tooth is fixed to the bone of the maxilla or mandible. 
     For this purpose, endosseous dental implants usually comprise an endosseous implant portion suitable for anchoring, for example by screwing, to the bone of the maxilla or mandible, and a transgingival portion that is suitable for crossing the gingiva to form a connection interface of the dental prosthesis. 
     Endosseous dental implants must therefore be realized in such a way as to provide a stable and long-lasting fixing of the dental prosthesis to the bone. 
     Furthermore, these implants may give rise to inflammation and/or infections caused by entry and deposit of residues in the connection area between the transgingival portion and the dental prosthesis, or even by the penetration of these residues deeper into the hole of the bone in which the endosseous implant portion is inserted. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a dental implant which simulates as much as possible the natural fixing of a tooth to the mandibular or maxillary bone, which allows a stable and long-lasting anchoring of dental prostheses, and which, at the same time, allows accumulations of organic material in the connection area between the implant and the prosthesis or at the bone implant site to be avoided. 
     Another object of the present invention is to provide a dental implant which allows the above mentioned objectives to be achieved with a reduced number of components. 
     These objects are achieved by a dental implant as described and claimed herein. 
     Some advantageous embodiments are also described. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Further features and advantages of the dental implant according to the present invention will result from the description below of preferred embodiments thereof, provided purely by way of indication and non-limiting examples, with reference to the accompanying figures, wherein: 
         FIG.  1    is an elevation view of the dental implant according to the present invention, in one embodiment; 
         FIG.  2    is a view in separate parts, and in partial section, of the dental implant of  FIG.  1    and of an abutment, with relative abutment fixing screw; and 
         FIG.  3    shows, in partial section, the implant inserted into the alveolar bone and coupled to a prosthetic crown. 
     
    
    
     DETAILED DESCRIPTION 
     In the accompanying drawings, reference number  1  indicates, as a whole, an endosseous dental implant according to the present invention. 
     In a general embodiment, the implant comprises an endosseous implant portion  10  and a transgingival portion  12 . 
     The endosseous implant portion  10  extends along an implant axis X. This portion has an elongated shape and is suitable for anchoring the implant to the maxillary or mandibular alveolar bone  4 . 
     The transgingival portion  12  extends from the implant portion  10 . The transgingival portion  12  is suitable for crossing the gingiva  5  and forms, on the opposite side with respect to the implant portion  10 , an implant-prosthesis connection platform  14 . 
     In other words, the platform  14  constitutes the support plane for an abutment  3  of a dental prosthesis  2 . 
     In one embodiment, the endosseous implant portion  10  and the transgingival portion  12  are integrally formed in a single piece. 
     The transgingival portion  12  is sized in such a way as to respect the so-called “biological width” (that is the amount determined by the soft tissues, epithelium and connective tissue), moving the critical area of the implant-prosthetic connection away from the bone crest so as to determine a “barrier of fibers” to protect the deeper spaces. In this way, it is possible to prevent peri-implantitis which is the main cause of implant failure due to inflammatory and infectious causes. 
     Therefore, the implant according to the present invention is of the type known by the term “tissue level” (that is with the implant-prosthetic connection at the soft tissue level), unlike the so-called “bone level” implants in which the implant-prosthetic connection is located at the level of the bone crest or below it. 
     The axis perpendicular to the platform  14  is defined as the prosthetic axis Y, in the implant according to the present invention the implant axis X is inclined with respect to the prosthetic axis Y. 
     For example, the inclination between the prosthetic axis Y and the implant axis X is between 10° and 45°. 
     The implementation of the implant with the implant axis X inclined with respect to the prosthetic axis Y allows the natural anatomy of the tooth to be followed, allowing for prosthesization with a reduced number of implant components. 
     According to an aspect of the present invention, the transgingival portion  12  forms a side wall  12 ′ with a diameter which is equal to or less than the diameter of the endosseous implant portion  10  and progressively decreases at least in a distal transgingival portion  12   a , or neck, ending with the implant-prosthesis connection platform  14 . 
     In other words, the transgingival portion  12  is devoid of any edge or protrusion so as to give this portion a larger diameter than the diameter of the endosseous implant portion  10  at the junction with the transgingival portion  12 . 
     In other words, with the possible exception of a curved connecting portion—described below—which may have a diameter at most equal to that of the endosseous implant portion  10  at the junction with the transgingival portion  12 , the latter has convergent shape, that is tapered, towards the platform  14 . 
     As a result of this convergence or tapering, the implant-prosthetic connection platform  14  has a smaller diameter than the (maximum) diameter of the endosseous implant portion  10 . For example, the latter has a diameter D between 3 mm and 6 mm and the implant-prosthetic connection platform has a diameter d between 2.5 mm and 4 mm. 
     In one embodiment, the implant-prosthetic connection platform  14  is contained within the projection of the endosseous implant portion  10  along the implant axis X. 
     More in detail, in one embodiment, the transgingival portion  12  comprises the distal transgingival portion  12   a , which defines the implant-prosthesis connection platform  14  and extends symmetrically about the prosthetic axis Y, and a connecting transgingival portion  12   b , which connects the distal transgingival portion  12   a  to the endosseous implant portion  10 . 
     In some embodiments, the side wall  12 ′, that is the neck, of the distal transgingival portion  12   a  is a conical wall or a parabolic surface portion or a hyperbolic surface portion. 
     In the embodiment illustrated in the drawings, the connecting transgingival portion  12   b  is a curved portion with a substantially constant diameter. 
     For example, considering for simplicity the platform  14  extending in a horizontal plane, the connecting transgingival portion  12   b  allows for the connection between the distal transgingival portion  12   a , which extends around the prosthetic axis Y, which in this example is a vertical axis, and the endosseous implant portion  10 , which extends along the implant axis X, which in this example is inclined with respect to the vertical. 
     In one embodiment, an anti-rotation element  20  of male type extends from the implant-prosthetic connection platform  14  that is suitable for coupling geometrically with an anti-rotation portion  22  of female type of an abutment  3 . 
     The anti-rotation element  20  is also integrally formed in a single piece with the transgingival portion  12  and with the endosseous implant portion  10 . 
     For example, the anti-rotation element  20  of male type is a prismatic projection, for example with a hexagonal cross section. 
     In an embodiment variant, an anti-rotation portion of female type is formed in the transgingival portion  12  and is suitable for coupling geometrically with an anti-rotation element of male type of an abutment  3 . 
     In one embodiment, a threaded hole  24  is obtained in the transgingival portion  12  that is suitable for receiving the threaded shank  26 ′ of an abutment connection screw  26  which stably connects the abutment  3  to the implant  1 . 
     In one embodiment, the threaded hole  24  affects only the distal transgingival portion  12   a , that is it does not also extend into the connecting transgingival portion  12   b , neither into the endosseous implant portion  10 . 
     The dental prosthesis  2  may in turn be cemented, screwed or otherwise made integral with the abutment  3 . 
     It should be noted that the implant according to the present invention allows for the use of an abutment connection screw  26  with a diameter equal to or greater than 1.5 mm, to the advantage of the stability of the anchorage between the prosthesis and the implant. 
     In one embodiment, the endosseous implant portion  10  is, or comprises, a threaded portion for screwing into the bone. 
     As mentioned above, the endosseous implant portion  10  is the portion of the implant that is responsible for determining the so-called “osseointegration”, that is, the intimate contact between the bone and the implant surface that allows the ability of the implant to transfer functional prosthetics loads to the bone. 
     In one embodiment, the threaded portion has coils with a pitch equal to or less than 0.6 mm in order to allow for fine adjustments of the prosthetic axis without leading to excessive sinking of the implant into the alveolar bone. 
     In one embodiment, materials used for making the implant are titanium or zirconium. 
     It is underlined that the transgingival portion with convergent geometry is one of the particular features of the proposed angled implant: the progressive reduction of the diameter in the apico-coronal direction determines a greater stability of the soft tissues (epithelium and connective tissue), helping to maintain a “barrier of fibers” in order to protect the deeper structures. 
     The convergence of the emergence profile also allows for the creation of a conometric component in the implant-prosthetic connection. In this case, it is possible to make an abutment  3  with a conical base  3   a  which extends inferiorly from the support plane  3   b  adapted to lean against the platform  14  and which is suitable for embracing the distal transgingival portion  12   a  of the transgingival portion  12  of the implant with shape coupling and with friction so as to unload the occlusal forces onto a wider platform. 
     A double engagement is thus achieved between the abutment  3  and the implant  1 : a first engagement given by the coupling between the anti-rotation portions  20 ,  22  and a second engagement given by the coupling between the side wall  12 ′ of the distal transgingival portion  12   a  (transmucosal neck) and the conical base  3   a  of the abutment  3 . 
     It should be noted that the monolithic structure, that is in a single body without connections, of the implant formed by the endosseous implant portion and the transgingival portion has a series of surgical, mechanical and biological advantages. In particular: 
     surgical times are reduced, by not having to assemble an angled abutment on the implant just inserted into the bone; 
     the problems of unscrewing and disconnection between two distinct components are eliminated; 
     the resultant of the prosthetic load is advantageously coaxial to the implant axis X, while in the embodiments wherein the transgingival portion is screwed to the endosseous implant portion, the resultant of the load is eccentric due to the need to make the through hole for the fixing screw; 
     since there is no micro-movement between the two portions of the implant, inflammation of the peri-implant tissues is prevented; and 
     the absence of spaces between the two portions of the implant prevents bacterial contamination and the consequent peri-implantitis. 
     In order to meet contingent needs, a person skilled in the art may make changes, adaptations, and substitutions of elements with other functionally equivalent ones, to the embodiments of the dental implant according to the present invention, without departing from the scope of protection as described and claimed herein. Each of the features described as belonging to a possible embodiment may be obtained independently of the other described embodiments.