EP4648709A1

EP4648709A1 - Abutment for dental implant

Info

Publication number: EP4648709A1
Application number: EP24703421.8A
Authority: EP
Inventors: Fabrizio Guerra; Livia OTTOLENGHI; Roberto DI GIORGIO; Gabriella GALLUCCIO; Andrea CICCONETTI; Iole VOZZA; Gianna Maria NARDI; Denise CORRIDORE; Marta Mazur; Marco SANSOTTA; Roberta GRASSI; Laura SANSOTTA
Original assignee: Universita degli Studi di Roma La Sapienza
Current assignee: Universita degli Studi di Roma La Sapienza
Priority date: 2023-01-12
Filing date: 2024-01-11
Publication date: 2025-11-19
Also published as: IT202300000354A1; WO2024150162A1

Abstract

An implant abutment, with the purpose of preserving the volume and trophism of the cortical bone and of the gingival tissue, comprises : an inserting portion; a contact portion touching the gingiva, integral with said inserting portion; a projecting portion with substantially circular shape projecting with respect to said contact portion to protect the gingival mucosa, integral with the contact portion through a concave profile; and a coronal portion integral with said projecting portion, whereon the prosthetic crown is installed, wherein the inserting portion, the contact portion, the projecting portion and the coronal portion are formed by one single piece which defines the abutment.

Description

ABUTMENT FOR DENTAL IMPLANT

Description

The present invention relates to an implant abutment , in particular an implant abutment to be used with dental implants , with a customi zed shape of the intramucosal portion maximi zing the mechanical stability of the mucous seal , thus by minimi zing peri-implant itis .

In particular, the invention relates to an implant abutment with customi zed and optimi zed sizes and profile even in the intramucosal portion, to preserve the volume and trophism of the bone of the alveolar ridge , which frequently, at various level , is atrophic, and of the gingival tissue , favouring tightness and mechanical stability of the mucosal seal , essential factors for the implant preservation .

With reference to the above-mentioned use example , implantology has demonstrated to be a valid therapeutic option in treating more or less extensive edentulism . Nevertheless , implantology is far from being free of complications . In fact , it requires a careful diagnostic path, selecting patients who can achieve therapeutic success , that is a complete and long-lasting osteo- integration of the implant that fully satis fies , not only functional requirements , but even the aesthetic ones which, to date , should always be guaranteed by the dental professional . However, it has been noticed over the years that to obtain this implant success , the simple osteo- integration ( required to be able to functionally load the implant prosthesis ) is not suf ficient , on the contrary it is necessary to obtain an adequate seal by the peri-implant soft tissues , to keep unaltered the achieved results over time .

For several decades , the prosthesis on implants has been a valid and predictable therapeutic option in dentistry . Nowadays , thanks to the level and to the achieved standards , implantology plays the role of elective prosthetic technique for the resolution of simple mono- edentulism and more extensive edentul ism .

The mechanical stabil ity and trophism of the soft tissues , which have to be a stable seal insulating implant ' s and alveolar bone ' s oral cavity, is a fundamental requirement for the purposes of short- , medium- and long-term implant success . To guarantees a long-term success to the implant treatment , an early and ef fective healing of the surrounding soft tissues is essential ; thus , to preserve function and aesthetical results , it is required to protect the obtained osteo-integration with a robust biological seal of neighbouring soft tissues . Therefore , several authors assert that the formation of an earlier, ef fective , and durable biological barrier, capable of protecting the peri-implant structure , is essential , to avoid bacterial penetration which could compromise both the initial healing and the long-term success . The interface of connective tissue is considered of primary importance supporting epithelium and locking its apical migration . Therefore , the possible lack in mechanical resistance of the soft tissues can invalidate the prognosis of the dental implants , both, through the above-mentioned bacterial infiltration in the mucosal means , and through the break down and collapse of the gingival margin, with consequent retraction, due to the forces exerted by the masticatory bolus or by the compressive action of voluminous prosthesis structures .

It is now accepted that materials such as titanium and, recently, zirconium, due to their surface physicochemical features , are biocompatible i f used in trans-mucosal portion of the implant abutment ; it has been also ascertained that , in this connection, the composite resins reveal to be a problem due to their tendency to accumulate plaque and due to their physical-chemical features . Likewise , the need of biological space , mainly as passage height between bone and oral cavity, is accepted; all implant systems provide an abutment portion, mostly with a smooth surface , apt to interact with the gingiva . Likewise , the need of surrounding the implant contingency with gingiva having an appropriate thickness , height , trophism and of adhering-like tendency, is accepted as well , this occurrence being sometimes influenced by the single implant site anatomy . The abutment-implant connection speci ficity has been investigated in the related literature as well , highlighting the stabil ity features thereof , and the sealing tightness between abutment and implant , in connection with a possible formation of a bacterial contamination site .

Observing the implant systems , a considerable variability in shape of the mucosal portion has been found, from hemispherical to convex, conical diverging in the coronal direction, cylindrical and concave , such variability being perceived even in the di f ferent solutions proposed by the very same company . Sometimes , shape and si zes are linked to the need of pairing the diameter of the implant to the diameter of the corona collar, otherwi se the diameter is imposed by the type of connection, or other criteria are followed as well , such as in the hemispherical abutments . In literature , in-vivo studies of simple comparison between the profiles can be found .

Currently, the dental implants , especially in the trans- mucosal portion of the abutment , are not designed to adapt themselves to single patients , and no commercial model can be found as suitable for all implant sites .

An example of implant abutment i s shown in patent No . EP 1096895 Bl , related to a Morse connection implant abutment comprising an intermediate connection which is cold bendable using two tubular instruments. The intermediate portion has a cylindrical shape and a diameter equal to that of the Morse cone base connecting to an implant.

To allow the cold bending of the connection, the preferred diameters of the intermediate connection and of the cone base are comprised between 1.5 mm and 2 mm. Usually, diameters below 2 mm are used under particular conditions, wherein the prosthetic load is low since the abutment, once inserted in the implant, behaves like a fixed beam with solid circular section constrained to one end, i.e. to the osteo-integrated implant.

Its most critical stress is the bending thereof, since its resistance to bending module is Wfi = nD³/32; thus, its diameter D considerably affects the resistance since the latter varies, as it can be seen from the formula, with the cube of its diameter, hence small variations in diameter sensibly vary the resistance of the abutment: an abutment with diameter of 3 mm resists 1.73 times more than an abutment of 2.5 mm and 3.73 times more than one of 2 mm.

Therefore, the need for a reduced diameter allowing the cold bending also reduces the resistance to the abutment bending, making it unsuitable to all types of dental implant .

Moreover, the cold bending generates residual stresses in the bent metal, by further weakening the abutment.

At last, the invention does not provide any element related to the gingiva playing the role of mucosal protection and preserving the peri-implant tissues.

An additional example of abutment with Morse connection is shown in US patent application No. 2018/0271624 Al, and it is designed to correct the angular discrepancies between the implant axis and the axis of the prosthetic crown, through a process of bending the manufactured product performed with a suitable device . The proposed procedures do not involve the use of digital technology at least until the placement of the abutment in patient ' s mouth . The procedure provides the making of an intermediate product , i . e . a thermoplastic abutment foldable inside the mouth, to be approximately implemented in patient ' s mouth and with the function of a guiding model in the oral extrabending of the finished product .

The cold bending process deforms the structure which loses even its circular shape . In particular, the diameter between the portions , inside and outside the curve , is reduced; to avoid that the Morse cone is altered by such deformation, it is protected by a strengthening expendable tract and by the lesser bending resistance of the reduced diameter tract to be folded, diameter which is smaller than the diameter of the cone base .

This document discloses an abutment with a bent portion having smaller diameter than the diameter of the Morse cone base , wherein the bent portion is further weakened by the bending procedure , making the bent portion a weakness point ; for such tract an example of abutment with a bending point of 2 . 2 millimetres is made , and this si ze is usually restrained to particular and extreme situations .

Moreover, even in this example no reference is made to customi zations of a marginal perimeter covering the gingiva by protecting the mucosa thereof .

An abutment-dental implant system is described in US patent application No . 2022 / 0378556 Al , and it consists of a customi zed abutment , within the limits imposed by the presence of an internal cavity, both in the portion in contact with the dental prosthetic crown and in the trans- mucosal portion; the abutment being connected to the implant through a peculiar through-screw conical connection, apically provided with an anti-rotation system allowing one single position for inserting the abutment in the implant , designed to avoid errors in the abutment positioning .

The peculiarity of such anti-rotation system is that , being asymmetric, it allows one single position .

The limit of this system is the impossibility to adapt the abutment to the individual anatomy of the single case , and the introduction of implant ' s prothesis in a not ideal position .

The abutment with passing-through screw must develop along the implant longitudinal axis , due to the screw seat emptying the central portion thereof ; then, it is not possible to tilt the abutment and to of fset the portion as well , with respect to the prosthetic crown and to the implant axis .

Without these correction opportunities while the prosthesis is implanted, the surgical procedure forces to put the implant in an ideal position with a little margin of error ; however, not rarely, anatomical limitations of the single case do not allow to place the implant in an optimum position .

In US patent appl ication No . 2020/ 0197135 Al , the abutment consists of two components , an intermediate one which is connected to an implant by means of a conical connection with retention by a screw integrated in the intermediate portion, and by a corresponding thread in the implant ; a coronal component which is connected to the intermediate one with a conical coupling with screw, in this second case the screw not being integrated, but it is a passing- through screw, the two conical couplings having equal shape and si zes . Disadvantageously, the intermediate component of the proposed system cannot be modi fied in any way, even i f it can be implemented in variable lengths , since the precise coupling with the coronal component must be kept , having a passing-through screw with a related cavity does not allow tilting, either to its proj ecting portion or in its coupling with the coronal component .

The shape and angulation corrections can be performed only on the coronal component , and they are structurally limited by the hole of the passing-through screw .

It should be also considered that the height of the intermediate component cannot be reduced below a certain limit , thus causing problems in case of thin mucosa or implants not placed deep enough .

In case of implants positioned tilted or misaligned with respect to their ideal position, the intermediate component does not allow corrections and, since it has an equal height throughout the perimeter, it does not allow to follow the course of the gingiva .

Moreover, the connection between abutment and implant implemented with cone and screw involves larger diameters of the implant , which cannot be used when implants with a diameter smaller than 4 mm are needed, especially i f the screw is a passing-through-screw; with a Morse connection, instead, implants with diameter of 3 . 5 and 3 mm are available , which can be used in particular situations .

The technical problem underlying the present invention is to provide an implant abutment allowing to obviate the drawbacks mentioned with reference to the known art .

Such problem is solved by an implant abutment as defined in the enclosed claim 1 , which generally comprises a truncated conical inserting portion which can be mechanically coupled to a corresponding truncated conical cavity of a dental implant , and a contact portion touching the gingiva . Said contact portion being integral with said inserting portion and having a substantially cylindrical shape , wherein all cross sections always have diameters a little larger than or equal to that of the largest circular section of the inserting portion, thereby the diameter reduction guarantees the mechanical resistance of the abutment and preserves the volume and trophism of alveolar ridge ' s bone and of gingival tissue .

The abutment also comprises a proj ecting portion with a substantially circular shape , which can be adapted to the needs of the single patient , the proj ecting portion raising substantially hori zontally with respect to said contact portion, to protect the gingival mucosa, said proj ecting portion being in integral with said contact portion through a concave profile ; at last , the abutment comprises a coronal portion integral with said proj ecting portion, thereon the prosthetic crown is installed .

Said inserting portion, said contact portion, said proj ecting portion and said coronal portion being integral to each other defining said abutment , said abutment being extended along a vertical direction identi fied by a vertical axis matching with the axis of symmetry of the truncated cone defined by the inserting portion . However, there is the possibility of tilting the contact portion j ust above the inserting portion, to obviate situations wherein the implant must be tilted in peculiar ways .

In fact , the abutment is customi zed by modelling an integral single piece at said contact portion and/or said proj ecting portion and/or said coronal portion based upon the needs of individual anatomy and of said dental implant position .

The main advantage of the implant abutment according to the present invention lies in the fact of comprising a proj ecting portion defined upon the morphological detection of the profile of the implant site preserving the peri-implant tissues , by minimi zing the overall dimensions for the tissue volumes benefit , for their trophism, for their mechanical stability and for the mucosa sealing as well .

Another advantage is related to the concept of the smallest possible diameter of abutment ' s contact portion, therefore the largest diameter of the inserting portion is selected based upon the thickness of the bone at the implant site ; said diameter is kept the same or it is selected to be a little larger at the contact portion, since the maximum limit of the bending module resistance of the abutment is determined by the cubed diameter of the abutment where proj ecting from the dental implant ; therefore , an increase thereof in the contact portion increases the resistance thereof , but damages the mucosal seal , whereas a diameter reduction greatly compromises the resistance thereof . However, it is not necessary to maintain with absolute precision the diameter of the inserting portion, a little increase is not harmful for the gingiva sealing and it provides a structural safety margin .

An additional advantage of the implant abutment is given by the fact of being obtainable from one integral single piece , allowing the tilting of one or more portions without stressing the material with cold folds and consequently having limits in the maximum diameters of the abutment .

Said implant abutment of fers considerable functional and aesthetical advantages with respect to a standard abutment , and it precisely suits to the morphological variables of the implant site .

The present invention will be described hereinafter according to a preferred embodiment example thereof , provided by way of example and not for limiting purposes with reference to the enclosed drawings , wherein : * figure 1 shows a front view of the section of an implant abutment according to the invention, of a dental crown and of a dental implant ;

* figure 2 shows a perspective view of an unfinished abutment millable with a CNC machine ;

* figure 3 shows a section of the milling section of the implant abutment according to figure 2 ;

* figure 4 shows a perspective three-dimensional view of a preferred embodiment of the implant abutment according to the invention;

* figure 5 shows a perspective three-dimensional view of another preferred embodiment of the implant abutment according to the invention;

* figure 6 shows the section of an impression and of an elastomer-made model of the implant site , with a waxing between the dental implant and the top of the gingiva ;

* figure 7 shows the millable abutment inserted in the elastomer-made model ;

* figure 8 shows a perspective view of a preferred embodiment of the unfinished abutment according to the invention, with a straight truncated conical coronal portion, said abutment being manually millable to be customi zed;

* figure 9 shows a perspective view of a preferred embodiment of the unfinished abutment according to the invention with a tilted truncated conical coronal portion, said abutment being manually millable to be customi zed;

* figure 10A shows a side view of a schemati zed preferred embodiment of the abutment according to the invention, with a tilted and misaligned truncated conical coronal portion and a customi zed marginal portion; * figure 10B shows a side view of a schemati zed preferred embodiment of the abutment according to the invention with a misaligned truncated conical coronal portion and a customi zed marginal portion; and

* figure I OC shows a side view of a schemati zed preferred embodiment of the abutment according to the invention with a tilted and misaligned truncated conical coronal portion, a customi zed marginal portion and a tilted contact portion .

With reference to the figures , an implant abutment , in particular intended to be used with dental implants is designated as a whole with 1 , and it will be mentioned hereinafter shortly as abutment .

It comprises a truncated conical inserting portion 2 which can be mechanically coupled to a corresponding truncated conical cavity 3 of a dental implant 4 .

The inserting portion 2 is a standard portion which can be coupled to the dental implant 4 anchored to the patient . Said inserting portion 2 vertical ly extends and its length corresponds to the height of the truncated cone , and it comprises a lower end 2 ' . The elements which can be modi fied in the inserting portion 2 are the length, the taper angle and the materials with which the abutment 1 is implemented .

Preferably, said materials are titanium al loys .

According to the preferred embodiments shown in figure , the length prevents the contact between the lower end 2 ' of the inserting portion 2 and the dental implant 4 ; in fact , in the conical coupling the contact must be only between the conical surfaces . The tightness of the coupling increases when the friction coef ficient of the used materials increases , and when the taper angle of the inserting portion 2 decreases with respect to the taper angle of the truncated conical cavity of said dental implant , based on this the taper angle is selected . Preferably, the inserting portion 2 comprises a first taper angle little greater than a second taper angle of the truncated conical cavity 3 of said dental implant 4 . Preferably, the conical surface of the inserting portion 2 must extend beyond the coupling margin with the implant 4 , thereby guaranteeing the correct contact on the whole conical surface of the implant 4 , since small variations in the sinking depth of the lower end 2 ' of the inserting portion 2 are possible , due to chewing or wearing of the dental implant 4 over time .

According to some embodiments , the length of the inserting portion 2 is comprised in the range from 3 . 5 mm to 4 . 5 mm .

Preferably, the sum of the inserting portion 2 and of the contact portion 5 have a length comprised between 3 . 5 mm and 8 mm .

Preferably, the taper angle of said inserting portion 2 is comprised between 2 ° and 5 ° .

By continuing in coronal direction from the dental implant 4 , the abutment comprises a contact portion 5 touching the gingiva 6 , said contact portion being integral with said inserting portion 2 and having a roughly cylindrical shape wherein all cross sections keep always diameters little larger than or equal to that of the greatest circular section of the inserting portion 2 , in this way the diameter reduction guarantees the mechanical resistance of the abutment 1 and preserves the volume and trophism of cortical bone 6 ' and of gingival tissue 6 .

Said contact portion 5 has a variable length compatible with the anatomical features of the implant site , mainly determined by the thickness of the mucosa, by the insertion depth of the implant 4 and by its angulation; this portion is to be implemented with a reduced diameter but with a residual circular section preferably little larger than that of the inserting portion 2 . Maintaining the minimum diameter provides a safety margin to avoid compromising the structural resistance , considering that the structural bending resistance varies with the cube of the diameter .

Preferably, the maximum diameter of the inserting portion 2 is comprised between 2 mm and 3 . 5 mm, more preferably 3 mm .

Preferably, the diameter of said contact portion 5 is larger by three tenths of mm with respect to the maximum diameter of the inserting portion 2 , the dimensional superiority is to be considered as a safety margin for the preservation of the structural resistance .

Advantageously, the contact portion 5 with reduced section leaves the greatest possible volume to the soft tissues and it allows to avoid more invasive surgical manoeuvres such as the regulari zation one with decrease in the cortical bone 6 ' , sometime required with abutments having voluminous morphology and with implants positioned deeply, such manoeuvres , apart from harmful , since they erode the precious residual bone of the ridge 6 ' , are uncomfortable for the patient .

An additional advantage given by a reduced diameter is the respect of the gingival structures , in situation of reducing inter-proximal space with particularly near or tilted teeth or implants , of thin gingiva or with poor adhering component .

The abutment also comprises a proj ecting portion 7 with substantially circular shape proj ecting with respect to said contact portion 5 to protect the gingiva 6 , said substantially hori zontal proj ecting portion 7 being integral with said contact portion 5 through a concave profile 8 , and at last a coronal portion 9 integral with said projecting portion 7, thereon the prosthetic crown 10 is installed.

In the passage from the contact portion 5 to the projecting portion 7, an almost horizontal enlargement of the diameter joining to the gingival margin of the prosthesis is observed, the perimeter of this portion of abutment 1 has not necessarily to be circular, it can have different diameters to better adapt to the anatomy and, it follows the different levels of the gingiva 6 in its contour, in the sites with aesthetical relevance it can even be slightly subgingival and continue with the aesthetical portion of the prosthetic crown 10.

This projecting portion 7, even in collaboration with the prosthetic crown 10, implements a wished over-contour which, like a roof, mechanically protects the underlying mucosa, in full contrast with the necessities of a prosthetic crown 10 on a natural tooth, indeed the involved structures are different.

Preferably, said projecting portion 7 has a diameter comprised between 4.5 mm and 8 mm, more preferably 6 mm.

Preferably, said projecting portion 7 has a height comprised between 1 mm and 4 mm.

In some embodiments, the coronal portion 9 has a height comprised between 5 mm and 7 mm and when it has a truncated conical shape it can have a taper angle comprised between 1° and 15° .

Differently from the commercial abutments, the structure of the abutment 1 according to the invention, at the gingival margin, has a substantially horizontal contact with the mucosa and not vertical, leaving space to the mucosa and mechanically protects it.

Said inserting portion 2, said contact portion 5, said proj ecting portion 7 and said coronal portion 9 are integral to each other, defining said abutment 1 . The abutment 1 is extended along a direction identi fied by a vertical axis X matching with the axis of symmetry of the truncated cone defined by the inserting portion 2 .

In implantology, the concept of biological space is used to designate the gingiva portion 6 in contact with the implant 4 , it is evaluated mainly in its extension in height , and it carries out the function of insulating the bone ridge from the oral environment . The poor insulation eases a bacterial contamination with bone reabsorption, this reabsorption, i f limited, even i f negative , is commonly accepted as inevitable , i f progressive it can cause a peri-implantitis . The mucosal seal determines the short- and long-term success of the implant therapy .

The shape of the abutment 1 , to which the invention is related, is aimed at maximi zing the function of the gingival seal . The gingiva 6 surrounds the abutment 1 , in particular the contact portion 5 , and it exerts a pressure thereon, which is proven by the tendency of the mucosa to quickly decrease in diameter when a healing abutment is removed, this ef fect being linked to the fibre-elastic structure of the adhering gingiva 6 which tends to contract , and to the pressure of the interstitial liquids . Such ef fect will be greater as the volume of the periimplant gingiva 6 increases .

The decrease in diameter of the contact portion 5 increases the pressure exerted by the gingiva 6 through two synergic mechanisms , one being linked to the above-mentioned preservation of the volume of the tissues which thus guarantee greater tension in the wall surrounding the cylindrical cavity of the mucosa ; the other mechanism being linked to the physical principle of the "hollow cylinder" thereto the mucosa is assimilable , according to said principle the pressure P inside the cylinder is equal to the tension of wall T divided by the radius R that is :

P = T/R

As shown, the contact portion 5 with reduced diameter increases the pressure of the mucosa on the abutment 1 by acting on both factors at play, increase in tension T , due to the increase in the gingival hori zontal thickness and decrease in radius . Apart from this pressure increase , there is also maximi zation, compatibly with the mucosa thickness , of the portion of abutment ' s length 1 subj ected to such ef fect and to a decrease in the perimeter of the mucosa .

The adhesion of the mucosa to the abutment 1 is mainly linked to the ef fect of the elastic return of the mucosa and it does not benefit by the anatomical structures which, on the contrary, reinforce such adhesion in the natural tooth, this makes it displaceable from the trauma linked to the masticatory function, the proj ecting portion 7 of the abutment 1 gets around this with its roof-li ke overcontour shape , which protects the underlying mucosa, even the prosthetic crown 10 can participate in the roof function .

Preferably, the proj ecting portion 7 is not perpendicular to said vertical axis X ; in fact , in some preferred implementations shown in figures 1 , 3 , 4 , 5 it i s tilted to better adapt to the implant site .

This is also true for its shape , which can be irregular based upon the gingival tissue which has to protect .

Even the coronal portion 9 can be asymmetric and it can have a tilted axis of symmetry with respect to the vertical axis X ( figures 3 , 4 , 5 and 9 ) , this allows to correct the disparallelisms between teeth or between the implants .

According to some embodiments , said axis of symmetry is tilted with respect to the vertical axis X by an angle comprised between 10 ° and 25 ° .

Advantageously, the abutment 1 , the present invention relates to , is implemented to customi ze it on the patient anatomy, by making it optimi zed for each single implant site with the purpose of minimi zing the risk o f peri- implantitis and maximi zing the trophi sm of tissues .

Preferably, said coronal portion 9 is implemented in one single piece and of the same material with the abutment .

To implement the abutment 1 , the present invention relates to , one can proceed with an automated working method which uses a CNC machine , or with a manual method .

The preferred procedure , when an automated working method with numerical control milling machine is used, comprises the following steps :

• performing a digital impression with intra-oral scanner and the help of a trans fer 11 from digital impression; in this way the implant position, the morphology of the gingiva 6 , the shape of the dental elements of the two arches and the occlusal relationships are known;

• arranging a mil lable abutment 1 , as in figure 2 , comprising a support 12 compatible with the milling machine , a millable portion 13 which will become the coronal portion 9 , the contact portion 5 and the proj ecting portion 7 , and an uneditable inserting portion 2 ;

• arranging a software suitable for planning and implementing the abutment 1 according to the criteria for preserving a reduced diameter of the contact portion 5 , of the proj ecting portion 7 which follows the gingiva profile and of the coronal portion 9 with pos sible tilting correction ;

• polishing the abutment 1 . During processing, the material removal linked to polishing has to be considered, such removal can be relevant and little controllable with diamond abrasives , even with fine grain for polishing; during polishing it must be avoided to involve the inserting portion 2 .

In fact , the inserting portion 2 absolutely must not be modi fied, to not compromise irremediably the precision of coupling which, i f well made , is hermetically sealed, however its length can be variable to reduce the amount of material to be removed during processing, in case a longer contact portion 5 must be implemented .

Alternatively, the digital impress ion can be taken by scanning a model implemented by means of an analogic impression .

In case of the abutment implemented with manual milling the following steps are performed :

• taking a dental impression 14 made of elastomer, preferably silicone or polyether , with the help of an impression trans fer 11 ; and

• casting the plaster impression after having put a portion of gingiva made of elastomer in the portion surrounding the trans fer 11 ; preferably applying a wax thickness 15 around the trans fer 11 , so to increase the diameter thereof in the portion not involved in the plaster homolog up to the proj ecting portion 7 o f the gingiva margin of the abutment 1 .

Alternatively, it is also possible :

• casting the impress ion only made of elastomeric material , with the same waxing mode of trans fer, a second section model limited to the implant 4 or to the implants and to the possible adj acent elements , this will be used only for milling the contact portion 5 and the proj ecting portion 7 ; • measuring on the impression the minimum thickness of the tissues above the implant 4 , the possible need for an tilting correction and the most suitable si zes of the perimeter of the proj ecting portion being evaluated;

• selecting the suitable abutment 1 and inserting it in the elastomer-made model 14 by following possible small adj ustments with milling of the model or of the abutment 1 , once the abutment 1 is inserted, it is necessary to define and mill the profile between the contact portion 5 and the proj ecting portion, commonly called shoulder 7 of the abutment 1 , so that it follows the level of the gingiva 6 , and the perimeter of the proj ecting portion 7 ; said perimeter can be even moderately subgingival in the fields with greater aesthetic needs . The proj ecting portion 7 can be not circular to better adapt to the needs of the single site and it can be moderately misaligned with respect to the contact portion 5 of the abutment ;

• modelling the contact portion 5 with removal of the exceeding metal according to the already illustrated concept criteria ; and

• milling the coronal portion 9 of the abutment 1 according to the common criteria used in implant prosthesis .

The abutments which can be milled manually can have a variable length of the inserting portion 2 to adapt more easily to the di f ferent thicknesses of the tissues and a tilting of the coronal portion 9 for the situations in which a tilting correction is required .

To the above-described implant abutment a person skilled in the art , with the purpose of satis fying additional and contingent needs , could introduce several modi fications and variants , however all comprised within the protective scope of the present invention, as defined by the enclosed claims .

Claims

1. A customized implant abutment (1) to preserve the volume and trophism of the cortical bone (6' ) and of the gingival tissue, said implant abutment (1) comprising:

• a truncated conical inserting portion (2) which can be mechanically coupled to a corresponding truncated conical cavity (3) of a dental implant (4) ;

• a contact portion (5) touching the gingiva (6) , said contact portion (5) being integral with said inserting portion (2) and having a truncated conical shape with a taper angle slightly larger than or equal to said inserting portion (2) or a cylindrical shape with diameter slightly larger than or equal to said inserting portion (2) , said diameter of said contact portion (5) being so as to guarantee the mechanical resistance of the abutment (1) and to preserve the volume and trophism of the cortical bone (6' ) and of the gingival tissue;

• a projecting portion (7) , with substantially circular shape, projecting with respect to said contact portion (5) to protect the gingival mucosa, said projecting portion (7) being integral with said contact portion (5) through a concave profile (8) ;

• a coronal portion (9) integral with said projecting portion (7) , whereon a prosthetic crown (10) is installed; said inserting portion (2) , said contact portion (5) , said projecting portion (7) and said coronal portion (9) being formed by one integral single piece which defines said abutment (1) , said abutment (1) extending along a direction identified by a vertical axis (X) matching with the axis of symmetry of the truncated cone defined by the inserting portion (2) and being able to be customized by modelling said solid single piece at said contact portion (5) and/or said projecting portion (7) and/or said coronal portion (9) based upon the needs of the individual anatomy and of the position of said dental implant (4) .

2. The implant abutment (1) according to claim 1, wherein said projecting portion (7) is tilted and not perpendicular with respect to said vertical axis (X) .

3. The implant abutment (1) according to one or more of the preceding claims, wherein said projecting portion (7) is misaligned with respect to said vertical axis (X) .

4. The implant abutment (1) according to one or more of the preceding claims, wherein the coronal portion (9) has the shape of a truncated cone with tilted axis of symmetry with respect to said vertical axis (X) .

5. The implant abutment (1) according to one or more of the preceding claims, wherein the contact between the inserting portion (2) and the dental implant (4) takes place only between their conical surfaces, said inserting portion (2) having a first slightly larger taper angle than a second taper angle of the truncated conical cavity (3) of said dental implant (4) , thereby preventing that a lower end (2' ) of said inserting portion (2) comes in contact with said dental implant (4) .

6. The implant abutment (1) according to one or more of the preceding claims, wherein the taper angle of the inserting portion is comprised between 2° and 7°.

7. The implant abutment (1) according to one or more of the preceding claims, wherein the taper angle of the contact portion is comprised between 2° and 8°.

8. The implant abutment (1) according to one or more of the preceding claims, wherein the contact portion (5) has a vertical extension comprised between 1 mm and 4 mm.

9. The implant abutment (1) according to one or more of the preceding claims, wherein the contact portion (5) has a diameter comprised between 2 mm and 3.5 mm.

10. The implant abutment (1) according to one or more of the preceding claims, wherein the projecting portion (7) has a diameter comprised between 4 mm and 8 mm.

11. A method for implementing a customized implant abutment starting from a dental impression to know the position of a dental implant (4) , the morphology of the gingiva (6) , the shape of the dental elements of the two arches and the occlusal relationships according to claim 1, wherein the method comprises:

• arranging an abutment (1) , millable from solid, comprising a millable portion (13) becoming the coronal portion (9) , the contact portion (5) and the projecting portion (7) , and an uneditable inserting portion (2) which can be mechanically coupled to said dental implant

12. The method according to claim 11, wherein if said dental impression has been obtained digitally with intraoral scanner and the help of a transfer (11) from digital impression, said abutment (1) millable from solid comprises a support (12) compatible with a milling machine and said method comprises:

• providing a software suitable to design and to implement the abutment (1) according the criteria of: keeping a diameter of the contact portion (5) slightly larger than or equal to the inserting portion (2) , so as to guarantee the mechanical resistance of the abutment (1) and to preserve the volume and trophism of a cortical bone (6' ) and gingival tissue, and with possible tilting correction, of the projecting portion (7) which follows a gingival profile and of the coronal portion (9) with possible tilting correction;

• polishing the contact portion (5) , the projecting portion (7) and the coronal portion (9) .

13. The method according to claim 12 which comprises:

• arranging a dental implant (4) , comprising a truncated conical cavity, in said dental impression and said inserting portion (2) in contact with said dental implant (4) along their conical surfaces;

• measuring on the impression the minimum thickness of the tissues above the impression (4) , by evaluating a suitable angulation and perimeter and shape of the projecting portion (7) , so as to follow a surface of said dental impression;

• selecting the abutment 1 suitable to insert it in the dental impression, making possible small adjustments milling the impression or the abutment 1;

• milling the contact portion (5) and the projecting portion (7) to better adapt to the needs of the single site by providing the possible tilting of the contact portion (5) by keeping its perimeter slightly larger than or equal to that of the inserting portion (2) and the customized milling procedure of the projecting portion (7) following said surface to be coated;

• milling the coronal portion (9) of the abutment (1) .