Multi-unit abutment

Abstract

The present disclosure relates to an abutment for an assembly of a dental restoration, preferably for multiple teeth. The abutment comprises a coronal interface region connectable to the dental restoration, wherein the coronal interface region includes a coronal interface axis and a flat contact surface, an apical interface region connectable to a dental implant and comprising an apical interface axis, between the coronal interface region and the apical interface region an intermediate region, wherein apically of the flat contact surface the intermediate region includes a cylindrical section with a height of 0.25 mm or less and a tapering portion tapering in the direction of the apical interface region. The disclosure also relates to a method of manufacturing an abutment.

Description

[0001] MULTI-UNIT ABUTMENT

[0002] TECHNICAL FIELD

[0003] The present invention relates to an abutment for an assembly to a dental restoration that may include multiple teeth and a method of manufacturing such an abutment.

[0004] BACKGROUND OF THE INVENTION

[0005] When designing and producing implant-based dental restorations, close attention is drawn to the preservation and restoration of the gingiva. The gingiva does not only cover the bone tissue of the dental arch (maxilla or mandible) but also an apical portion of a dental restoration such as portions of an abutment and artificial tooth. This coverage is particularly important for the aesthetics of the dental restoration since it particularly prevents the support structure of a dental restoration from being visible for another person when looking at it during everyday life.

[0006] Accordingly, the more gingiva can be restored the better is the concealment of the dental restoration from being recognized as such. In this respect, it should also be considered that the gingiva tends to recede with age of a patient. Due to this, a dental restoration may become recognizable after some time although not having been visible after treatment.

[0007] In view of this, it remains of great interest to identify design features of dental restorations that help fostering the presence and health of the gingiva, in particular in case of dental restorations that include multiple teeth.

[0008] SUMMARY OF THE DISCLOSURE

[0009] The following disclosure addresses objectives in relation to restoring and preserving the gingiva when providing a dental restoration, in particular a dental restoration comprising multiple artificial teeth (e.g., from a bridge to a full-arch dental restoration).

[0010] To address these objectives, the present disclosure provides an abutment for assembly of a dental restoration, the dental restoration particularly being for replacing multiple teeth. The abutment comprises a coronal interface region connectable to the dental restoration, wherein the coronal interface region includes a coronal interface axis and a flat contact surface, as well as an apical interface region connectable to a dental implant and comprising an apical interface axis. Between the coronal interface region and the apical interface region the abutment further comprises an intermediate region, wherein apically of the flat contact surface of the coronal interface region the intermediate region includes a cylindrical section with a height of 0.25 mm or less and a tapering portion tapering in the direction of the apical interface region.

[0011] The flat contact surface is adjacent to the coronal side of the cylindrical section (in other word, it forms a coronal side or surface of the cylindrical section). The flat contact surface is configured as a sealing surface. In this way, a central part of the abutment is sealed off in the assembled state (i.e. , upon contact with another dental component such as an artificial tooth, artificial teeth or a substructure thereof). Thus, the flat contact surface may be provided as a measure against infections that may in turn cause periimplantitis and / or a receding gingiva.

[0012] By providing the cylindrical section with a height of 0.25 mm or less and preferably in a range of 0.15 mm to 0.25 mm, the sealing surface is provided with a rigidity, in particular at the peripheral edge, that is able to withstand masticatory forces while keeping the aforementioned sealing effect of the surface. In other words, the cylindrical section has a height greater than 0 mm as seen in figures 2 or 4 to achieve the aforementioned effect. At the same time, the maximum height of the cylindrical section of about 0.25 mm allows to increase the length of the tapering portion and, thus, to increase the volume for soft tissue growth. Moreover, the relatively thin cylindrical section also forms a less visible peripheral edge even if it becomes visible from the outside. Below this peripheral edge the thickness of the gingiva increases due to the more coronally tapered design of the intermediate region.

[0013] Thus, the intermediate region has an outer surface that is configured to be in contact with soft tissue. Nonetheless, there may be also scenarios, in which the intermediate region is partly in contact with bone tissue (in particular, if the underlying implant is inclined in relation to the alveolar ridge). Here, the coronal shift of the tapering portion also allows for a smaller cross-section at the apical side of this portion so that less bone tissue needs to be removed when preparing the installation of the abutment. At least adjacent to the cylindrical section of the intermediate region, the tapering portion preferably has a curvature with a radius of at least 0.45 mm, preferably 0.5 mm, and in particular a maximum radius of 1 .5 or 1 .0 mm.

[0014] In other words, the tapering section has a curvature, in particular a concave and / or convex curvature, in a cross-section along the coronal interface axis or the apical interface axis as seen in figures 2 or 4.

[0015] The minimum curvature prevents the tapering portion of the intermediate region of having an inside corner that may tend to be too narrow so that the soft tissue may not grow into this corner. The maximum radius allows at the apical circumferential edge of the cylindrical section to provide a higher volume for the gingiva to grow into.

[0016] The flat contact surface is preferably perpendicular to the coronal interface axis (i.e., a fixation force of the assembly may also essentially fully serve as a sealing force to prevent an ingress from outside the abutment to the central part of the abutment).

[0017] The abutment may further comprise a rounded transition arranged between the intermediate region and the apical interface region.

[0018] The apical interface region is preferably directly connectable to a dental implant. This connection is generally manufactured with a different precision (in particular lower tolerances, i.e., higher precision) than the intermediate region configured to allow for attachment or ingrowth of soft tissue (i.e., gingiva). The transition between these two surfaces with different manufacturing tolerances may not only not be smooth but may even have an undesired roughness and / or topography due to an interference between these two surfaces. This may have an adverse effect on the strength of the abutment.

[0019] This effect may effectively be avoided by rounding this transition. The roundness of this transition may be concave and / or convex (as seen in a cross-section along the coronal interface axis or the apical interface axis). In other words, it may be formed as a groove and / or a rounded edge. The groove and / or rounded edge extend in a circumferential direction at least partly or fully around the abutment. Preferably, the rounded transition is manufactured by feeding a tool in the circumferential direction.

[0020] The apical interface axis and the coronal interface axis may intersect each other. Thus, the abutment may be an angled abutment instead of a straight abutment. The surface of the intermediate region is preferably concave on one side and convex on the other side as seen in a longitudinal cross-section in a plane in which the angle is formed by the two axes. In a straight abutment, the apical interface axis and the coronal interface axis are aligned.

[0021] The surface of the abutment is preferably at least partly covered by an oxide layer having an average thickness in a range from 60 nm to 170 nm and / or an average arithmetical mean height Sa in a range from 0.05 pm to 0.8 pm, preferably to 0.5 pm.

[0022] The combination of the oxide layer thickness of 60 nm to 170 nm and the surface roughness Sa of 0.05 pm (or 0.10 pm) to 0.8 pm or 1.0 pm, particularly in the intermediate region of the abutment (but may also substantially cover the coronal interface region and the apical interface region), has the following advantageous biological and clinical effects.

[0023] For example, the specific oxide layer thickness results in an interference color of the abutment that is yellow or pink when viewed by the human eye. Said coloring is beneficial to minimize grey shine-through effects through soft tissue when the abutment is installed. An improved soft tissue appearance can be achieved by changing the color from a metallic grey conventional encountered in the prior art to yellow or pink by deliberately adjusting the thickness of the oxide layer.

[0024] In addition, the presence of an oxide layer, in particular in case of a titanium oxide layer, the coronal implant region shows good biocompatibility, stimulating adhesion, proliferation, and extracellular matrix secretion of human gingival fibroblasts.

[0025] The surface of the abutment can further have an arithmetical mean height Sa in the range from 0.2 pm, preferably from 0.3 pm and further preferably from 0.4 pm to 0.8 pm, preferably to 0.6 pm and further preferably to 0.4 pm, and the oxide layer can further have an average thickness in the range from 80 nm to 130 nm, preferably to 150 nm and further preferably to 160 nm. By adjusting the oxide layer thickness, it is possible to fine-tune the color and / or the nanostructures of the abutment so as to further enhance them or adapt them to individual needs of certain indications or groups of patients.

[0026] The circumferential surface of the cylindrical section is at least partially along a circumferential direction flush with the surface of the tapering portion. In other words, the circumferential surface of the cylindrical section basically merges into the outer surface of the intermediate region along a circumferential portion thereof (i.e., a portion of the cylindrical section basically does not protrude from the part of the intermediate region located apically thereto). In another portion of the circumference of the abutment (e.g., a circumferentially opposite portion), there is preferably a distinct change of direction at the apical edge of the cylindrical section, where the surface of the intermediate region and the circumferential surface of the cylindrical section meet, so that the cylindrical section protrudes.

[0027] The apical interface region preferably comprises a tapered contact surface.

[0028] Similar to the flat contact surface of the coronal interface region, the tapered contact surface of the apical interface region is configured to seal off an inside of the abutment when being mounted to a dental implant. Preferably, the flat contact surface and / or the tapered contact surface have a lower surface roughness Sa than the intermediate portion. The tapered contact surface is preferably located on the side of or adjacent to the apical side of the intermediate region.

[0029] It is particularly preferred that the intermediate region has a milled surface structure and at least a portion of the apical interface region has a turned surface structure.

[0030] On the one hand, turned surfaces may be manufactured particularly smooth and uniform. Further, any traces on the surface due to turning are oriented in a circumferential direction. As a result, such a surface structure of the apical interface region provides advantageous characteristics as a sealing surface.

[0031] On the other hand, milled surface, in particular milled freeform surfaces, have a more complex and rough topography. Without wishing to be bound by theory, it is believed that this topography enhances the attachment and / or proliferation of soft tissue cells. The increased surface roughness provides more surface area for cell attachment and may improve the mechanical interlocking between the tissue and the abutment.

[0032] The abutment may comprise a through hole including a screw seat arranged for fixing the abutment to the dental implant via a dental screw. Such an arrangement is particularly advantageous for the sealing properties of the abutment since it allows to fasten the abutment to the dental implant basically without any relative rotation between the dental implant and the abutment while building up contact pressure between the sealing surface of the abutment and a sealing surface of the dental implant.

[0033] The disclosure further provides a method of manufacturing an abutment, in particular an abutment according to the disclosure of above. The abutment comprises a coronal interface region, an apical interface region, and an intermediate region in between the coronal interface region and the apical interface region. The method comprises the steps of machining a flat contact surface of the coronal interface region connectable to a dental restoration, machining the apical interface region having an apical interface axis connectable to a dental implant, and apically of the flat contact surface of the coronal interface region machining a cylindrical section of the intermediate region to a height of 0.25 mm or less and a tapering portion tapering in the direction of the apical interface region.

[0034] Machining the apical region, intermediate region, and coronal region in this manner results in an abutment having the advantages described above. Further, the different regions may also be machined by different techniques (e.g., milling, turning, etc.) and / or different machining parameters (e.g., for generating a predefined surface structure and / or roughness), wherein each region is itself preferably machined with the same technique and / or machining parameters.

[0035] For example, the apical and / or coronal interface region (in particular the contact surface thereof) may be machined to have a first surface roughness and the intermediate region may be machined to have a second surface roughness, wherein the first surface roughness is lower than the second surface roughness. Further the surface structure of the intermediate region is preferably multidirectional (i.e., manufacturing traces extend in multiple directions) whereas the surface structure of the apical interface region and / or coronal interface region is preferably substantially unidirectional and even more preferably substantially circumferential (i.e., manufacturing traces extend substantially in a circumferential direction).

[0036] A lower surface roughness has advantageous sealing properties. As described above, these sealing properties may alternatively or additionally be enhanced by using turning as manufacturing technique. Moreover, a higher surface roughness tends to have advantageous properties for the adhesion of soft tissue (i.e., gingival tissue). This adhesion may alternatively or additionally be enhanced by employing milling, in particular freeform surface milling, as manufacturing technique. Thus, either or both machining techniques may be used to produce the abutment from a blank.

[0037] The intermediate region is preferably machined by milling and the apical interface region is preferably machined by turning.

[0038] Further, the surface of the abutment is at least partially obtained by performing an anodic oxidation process to obtain above-described oxide layer. The surface of the abutment is preferably an anodized surface comprising an oxide layer.

[0039] SHORT DESCRIPTION OF THE DRAWINGS

[0040] The following figures schematically illustrate exemplary embodiments of abutments according to the present disclosure. In these figures, same reference signs refer to features throughout the drawings that have the same or an equivalent function and / or structure. It is to be understood that the figures only illustrate schematic examples of abutments in accordance with the present disclosure but without limiting the invention thereto.

[0041] Figure 1 illustrates a first embodiment of an abutment in accordance with the present disclosure;

[0042] Figure 2 illustrates a longitudinal cross-section of the exemplary abutment depicted in figure 1 ;

[0043] Figure 3 illustrates a second embodiment of an abutment in accordance with the present disclosure; and

[0044] Figure 4 illustrates a longitudinal cross-section of the exemplary abutment depicted in figure 3.

[0045] DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0046] A first embodiment of an abutment 1 in accordance with the present disclosure is illustrated in figures 1 and 2. A second embodiment of an abutment in accordance with the present disclosure is illustrated in figures 3 and 4. Generally, the abutment 1 comprises in a coronal-apical direction a coronal interface region 10, an intermediate region 30, and an apical interface region 20.

[0047] The coronal interface region 10 includes a coronal interface axis 11. Similarly, the apical interface region 20 includes an apical interface axis 21. The coronal interface axis 11 and the apical interface axis 21 each preferably correspond to a direction of assembly when mounting the abutment 1 to another dental component and the dental implant, respectively. In the exemplary embodiment of an abutment depicted in figures 1 and 2, the interface axes 11 and 21 are aligned. Alternatively, they may be inclined relative to each other (i.e. , they intersect each other as shown in figures 3 and 4).

[0048] As illustrated in the exemplary embodiment of figures 1 , 2 and 4, the coronal interface region 10 may include a thread (preferably an inner thread) for fastening a dental component of a dental restoration to the coronal side of the abutment 1 .

[0049] The coronal interface region 10 includes a flat contact surface 12. As described above, the flat contact surface 12 is preferably configured as a sealing surface that seals off the inside of the abutment 1 when being in contact with another sealing surface (particularly a flat sealing surface) of a dental component of a dental restoration to be supported by the abutment 1 .

[0050] The configuration of a flat contact surface 12 as a sealing surface has the advantage to be able to prevent an ingress of adverse substances (e.g., bacteria, viruses, pathogens, etc.) that may cause an inflammation as well as to prevent an ingrowth of soft tissue (particularly gingival tissue) in between the abutment 1 and a dental component coronal thereto. The same effect is achieved by the tapered contact surface 22 of the apical interface region 20 as will be described further below.

[0051] As particularly illustrated in figure 1 , the coronal interface region 10 may comprise engagement means 14. The engagement means 14 is preferably configured to allow for a driver to allow attaching the abutment 1 to an apical dental component, preferably a dental implant. This enhances the contact of the flat contact surface 12 to the other dental component and a sealing force acting between the abutment 1 and the dental component, since the driver does not interfere with said flat contact surface 12 when attaching the abutment 1 . For the same reason, the flat contact surface 12 preferably has a comparatively low surface roughness. Apically to the flat contact surface 1 , the abutment comprises an intermediate region 30. The intermediate region 30 is particularly configured for the attachment and growth of gingival tissue.

[0052] On the coronal side of the intermediate region 30, the intermediate region 30 includes a cylindrical section 31 . In other words, starting from the circumferential edge of the flat contact surface 12, a cylindrical section extends apically thereto and forms a cylindrical circumferential surface of the abutment 1 . The cylindrical section has a height or thickness (i.e. , length along the coronal interface axis 11 ) of at most 0.25 mm or less and preferably of at least 0.10 mm, preferably 0.15 mm, or more.

[0053] The height of the cylindrical section 31 provides the abutment 1 with a thickness (particularly in the circumferential peripheral region of the flat contact surface 12) that is able to maintain the above-described sealing properties under masticatory forces exerted by a patient. At the same time, a height of the cylindrical section 31 in that range provides the abutment 1 with more volume underneath the cylindrical section

[0054] 31 that protrudes from the remainder of the intermediate region 30 (i.e., the portion of the intermediate region 30 apically thereto).

[0055] Without wishing to be bound by theory, it is believed that even a fraction of a millimeter of additional gingiva covering the abutment 1 may well provide additional time of having an aesthetical pleasing dental restoration before a receding gingiva might partially render the abutment 1 of the dental restoration visible.

[0056] Also for this reason, the part of the intermediate region 30 located apically to the circumferential section 31 preferably has, as seen in a cross-section along the longitudinal axis of the abutment 1 (i.e., along the coronal interface axis 11 and apical interface axis 21 ), a concave profile.

[0057] For example, the abutment illustrated in figures 1 and 2 has a tapering portion

[0058] 32 with a minimum cross-section (in particular diameter) between the cylindrical section 31 and the apical end of the intermediate region 30 (i.e., the end adjacent to the apical interface region 20). Accordingly, the tapering portion 32 tapers from the cylindrical section 31 in the apical direction of the abutment 1 and from the apical end of the intermediate region 30 in a coronal direction. Thus, there may be two tapering parts along the tapering portion 32 that taper down to a minimum cross-section in opposite directions. The tapering parts are preferably adjacent to each other at the minimum cross section of the intermediate region 30 or may be separated by an intermediate section having a cylindrical cross-section (not shown).

[0059] Another example of a concavity along a tapering portion 30 of an abutment 1 will be described further below under reference to figures 3 and 4.

[0060] As described above, the tapering portion adjacent to the cylindrical section of the intermediate region may have a curvature with a radius of at least 0.45 mm, preferably 0.5 mm, and particularly a maximum radius of 1 .5 mm or 1 .0 mm. The tapering portion 32 may also have a profile in a cross-section along the longitudinal axis (i.e., longitudinal profile along the coronal interface axis 11 and the apical interface axis 21 ) that includes substantially straight or linear sections, in particular adjacent to the apical circumferential edge of the cylindrical section 31 .

[0061] These radii allow for the longitudinal profile of the coronal side of the tapering portion 32 of the intermediate section 30 to provide volume for soft tissue growth apically to the cylindrical section 31. In particular, the higher radii allow for the cylindrical section 31 to protrude with a thickness that increases in an inwards direction to a degree that provides sufficient strength to the abutment 1 and at the same time enhances the space for soft tissue to grow in and to allow for an enhanced coverage of the abutment 1. The lower radii may be particularly used along the concave longitudinal profile of the abutment 1 to bring the profile closer to the apical interface axis 21 (see figure 3).

[0062] Preferably, the tapering portion 32 of the intermediate region 30 begins at the apical circumferential edge of the cylindrical section 31 with a straight section and / or a curved section with a curvature of a relatively large radius followed by a curvature with a decreasing radius up to a minimum radius, which in turn is preferably followed apically with a curvature with an increasing radius. This provides the abutment, particularly an angled abutment as shown in figures 3 and 4 with a deeper concavity underneath the cylindrical section 31 .

[0063] As further shown in figures 3 and 4, the longitudinal profile of an angled abutment in a cross-section along a plane defined by the intersecting coronal interface axis 11 and the apical interface axis 21 is concave on one side (right side in figures 3 and 4) and convex on the opposite side (left side in figures 3 and 4). Providing the abutment with the convex profile may minimize the amount of bone tissue to be removed for installing the abutment 1 . On the convex side, the outer circumferential surface of the cylindrical section 31 is preferably flush with the profile of the adjacent tapering portion 32 apically thereto.

[0064] Further apical from the intermediate region 30 is the apical interface region 20. The apical interface region 20 comprises a tapered contact surface 22. As described above, the tapered contact surface 22 is preferably configured as a sealing surface that seals off the inside of the abutment 1 and the dental implant.

[0065] The above-described flat contact surface 12 and / or the tapered contact surface 22 preferably have a lower surface roughness than the outer circumferential surface of the intermediate region 30. Such a lower surface roughness is advantageous for sealing-off the inside of the abutment 1 whereas the comparatively higher surface roughness enhances the attachment of soft tissue to the abutment 1 .

[0066] The difference in surface roughness and, if present, also the difference in manufacturing traces (described in more detail above) may cause a transition 40 between the intermediate region 30 and the apical interface region 20 with an undesirable surface structure. To alleviate this surface structure, this transition 40 is preferably rounded by forming a circumferential groove and / or a rounded edge. Either roundness is preferably manufactured by feeding a tool in the circumferential direction along the transition 40 of the abutment 1. This configuration of the transition 40 prevents a reduction in strength of the abutment 1 and at the same time allows the two different surface structures for sealing and for soft tissue attachment.

[0067] For example, in the exemplary embodiment of an abutment 1 illustrated in figures 1 and 2, the transition 40 is formed as a rounded circumferential edge, wherein the abutment depicted in figures 3 and 4 has a transition 40 in the form of a circumferential groove.

[0068] The apical interface region 20 may further comprise an apical thread section 25 (in particular an outer thread) apically to the tapered contact surface 22. The apical thread section 25 is for fastening the abutment 1 to a dental implant. Such a configuration facilitates handling of the abutment 1 since there is no separated dental screw.

[0069] Alternatively, the abutment 1 may comprise a through hole 23 with a screw seat 24 (see cross-section of the abutment 1 depicted in figure 4). A dental screw (not shown) may be inserted through the through hole 23 to fasten the abutment 1 to a dental implant. In this way of fastening the abutment 1 , a relative rotation of the abutment 1 relative to the dental implant may be prevented. This advantageous for achieving the desired sealing effect of the tapered contact surface 22 of the abutment 1 with a corresponding surface of the implant and for adjacent soft tissue and bone tissue.

[0070] Further, to enhance the surface of the abutment 1 in terms of soft tissue attachment and / or color, the abutment 1 may comprise an oxide layer. Accordingly, the oxide layer is at least provided to the intermediate region 30 of the abutment 1 . Nonetheless, it may also be provided to the coronal interface region 10 and / or the apical interface region 20.

[0071] As described above, the oxide layer may have a thickness in the range of 60 nm to 170 nm. The oxide layer thickness can be measured on images of axial cross sections of the dental implant.

[0072] In addition, the surface of the coronal implant region has an arithmetical mean height Sa in the range from 0.1 pm to 0.8 pm or 1.0 pm. The parameter Sa is a standard parameter to characterize the roughness of a surface. A synonymous expression used for Sa is thus "surface roughness", which is also used for the present disclosure. The parameter Sa may be determined from white light interferometry measurements.

[0073] Preferably, the above Sa is an average area roughness, meaning that it was measured at various position of the intermediate region 30 or any one of the other abutment regions followed by calculating the mathematical average from all of the measurements. It is further to be noted that the here described surface roughness Sa preferably reflects a surface of the abutment 1 including the oxide layered formed thereon. Thus, the measured surface roughness may be seen as a superposition of the surface roughness of the surface of the abutment's base material, for example, as created by machining and the surface of the oxide layer on top of that. The original abutment's base material surface will possess an inherent roughness that is largely determined by the way the abutment itself is manufactured (as will be described further below) and its surface is finished. Further, the oxide layer formed on or forming the abutment surface also possesses an inherent roughness. Consequently, the overall surface roughness is a superposition of a microscale amplitude, low frequency roughness of an as-machined / finished abutment surface and a nanoscale amplitude, high frequency roughness of the oxide layer formed thereon. Preferably, the surface of the coronal interface region 10 and the apical interface region 20 is smooth, meaning it exhibits an as-machined microstructure, in particular comprising an arrangement of turning lines from the machining process. It is preferably non-porous and / or nanostructured. The feature "smooth" is mainly a qualitative way of describing the surface of the coronal implant region. The quantitative way is defining the surface roughness Sa as done above. Non-porous here means that surface of the coronal region does not exhibit a significant density or number of open pores that intersect the surface and create tiny holes thereon.

[0074] As-machined microstructure means that the surface of the abutment 1 exhibits a pattern originating from the machining of the abutment during its production. As previously discussed, said machining structure is preferably preserved and, thus, still superficially detectable and not buried by the superficial / superposed oxide layer. Nanostructure means that the oxide layer exhibits nanosized structures (such as recesses like golf-ball-like surface recesses) of less than 100 nm in diameter. Hence, the surface morphology of the coronal implant region is determined by both, the as- machined surface morphology and the oxide layer surface morphology. One example of such as-machined surfaces is a turned surface still exhibiting a regular pattern of fine turning lines that are covered, but not buried by the oxide layer. The pattern of turning lines leads to an oriented line roughness meaning that along the turning lines the line roughness would be low, whereas perpendicular to the turning lines it is higher due to turning lines and troughs alternating. In other words, the surface of the coronal implant region has an oriented roughness. If the turning lines are oriented circumferentially on the abutment’s surface they do not interfere but support the sealing functionality of the flat contact surface 12 and the tapered contact surface 22. Alternatively, the oxide layer may be configured to at least reduce the pattern of a turned surface to be used for sealing.

[0075] However, the intermediate region 30 configured to be in contact with soft tissue is preferably machined using milling (in particular freeform milling, for example with a ball-end cutter). The pattern generated by milling is at least less uniform and in particular multidirectional (in contrast to the unidirectional surface generated by turning or circumferential milling). Employing milling for machining the abutment, the pattern may even be planned to be non-uniform and / or multidirectional to create an abutment surface (particularly in the intermediate region 30) having above-noted advantageous characteristics for the attachment and growth of soft tissue. In other words, the above listed preferable features of the surface of the abutment 1 are strengthened by the surface of the abutment 1 optionally possessing both, a microstructure formed by machining, preferably in the form of a pattern of turning lines and in addition a nanostructure originating from the oxide layer formed on the as- machined surface. Said nanostructure may be characterized by nanoscale indentations, recesses, spherical features and / or a nanoscale hill-valley structure. Said nanostructure beneficially roughens the otherwise very smooth as-machined surface thereby conferring its desired functionality, in particular good tissue integration. Said nanostructures are distinguished with respect to pores, by normally having larger diameters than depths.

[0076] Accordingly, the attachment of the soft tissue may be enhanced by the design of the cylindrical section 31 , the longitudinal profile of the intermediate region 30 (particularly the tapering portion 32 apical to the cylindrical section 31 ), the type of machining used to generate the surface of the intermediate region 30 (in particular using milling), and / or an oxide layer formed as outer surface of at least a portion of the intermediate region 30.

[0077] Further, the type of machining may also be selected to machine the flat contact surface 12 of the coronal interface region 10 and / or the tapered contact surface 22 of the apical interface region 20 to at least alleviate soft tissue growth on such a surface (e.g. by using turning or milling in a circumferential direction). This effect may further be enhanced by generating an oxide layer with a thickness that reduces or covers (i.e. , smoothens) the surface structure or pattern.

[0078] Consequently, the present disclosure combines different approaches in a synergistic way to influence soft tissue growth on the surface or different surfaces of the abutment 1 .

[0079] Thus, the abutment is preferably manufactured with different surface properties. In particular, the flat contact surface 12 of the coronal interface region 10 that is connectable to a dental restoration and / or the tapered contact surface 22 of the apical interface region 20 are / is preferably machined by turning or circumferential milling.

[0080] Apically of the flat contact surface 12 of the coronal interface region 10 a cylindrical section 31 of the intermediate region is machined with a height (i.e., thickness) of 0.25 mm or less and with a tapering portion 32 tapering in the direction of the apical interface region 20. At least the tapering portion 32 and preferably also the cylindrical section 31 is machined by milling, in particular freeform milling.

[0081] These machining techniques are chosen and preferably performed with predetermined parameters to obtain a specific surface structure or pattern of the machined surface in view of the desired properties in relation to soft tissue growth and attachment.

[0082] REFERENCE SIGNS

[0083] 1 abutment

[0084] 10 coronal interface region

[0085] 11 coronal interface axis

[0086] 12 flat contact surface

[0087] 14 engagement means

[0088] 15 thread

[0089] 20 apical interface region

[0090] 21 apical interface axis

[0091] 22 tapered contact surface

[0092] 23 through hole

[0093] 24 screw seat

[0094] 25 apical thread section

[0095] 30 intermediate region

[0096] 31 cylindrical section

[0097] 32 tapering portion

[0098] 40 transition

Claims

CLAIMS1 . An abutment (1 ) for assembly of a dental restoration, preferably for multiple teeth, the abutment comprising: a coronal interface region (10) connectable to the dental restoration, wherein the coronal interface region includes a coronal interface axis (11 ) and a flat contact surface (12); an apical interface region (20) connectable to a dental implant and comprising an apical interface axis (21 ); between the coronal interface region (10) and the apical interface region (20) an intermediate region (30), wherein apically of the flat contact surface (12) the intermediate region includes a cylindrical section (31 ) with a height of 0.25 mm or less and a tapering portion (32) tapering in the direction of the apical interface region (20).

2. The abutment (1 ) according to claim 1 , wherein adjacent to the cylindrical section (31 ) of the intermediate region (30), the tapering portion (32) has a curvature with a radius of at least 0.45 mm, preferably 0.5 mm, and in particular a maximum radius of 1 .0 mm or 1 .5 mm.

3. The abutment (1 ) according to claim 1 or 2, wherein the flat contact surface (12) is perpendicular to the coronal interface axis (11 ).

4. The abutment (1 ) according to any one of the preceding claims, wherein the abutment further comprises a rounded transition (40) arranged between the intermediate region (30) and the apical interface region (20).

5. The abutment (1 ) according to any one of the preceding claims, wherein the apical interface axis and the coronal interface axis intersect each other.

6. The abutment (1 ) according to any one of the preceding claims, wherein the surface of the abutment is at least partly covered by an oxide layer having an average thickness in a range from 60 nm to 170 nm and / or an average arithmetical mean height Sa in a range from 0.05 pm to 0.80 pm, preferably to 0.60 pm.

7. The abutment (1 ) according to any one of the preceding claims, wherein the circumferential surface of the cylindrical section (31 ) is at least partially along a circumferential direction flush with the surface of the tapering portion (32).

8. The abutment (1 ) according to any one of the preceding claims, wherein the apical interface region (20) comprises a tapered contact surface (22).

9. The abutment (1 ) according to any one of the preceding claims, wherein the intermediate region (30) has a milled surface structure and at least a portion of the apical interface region (20) has a turned surface structure.

10. The abutment (1 ) according to any one of the preceding claims, wherein the abutment comprises a through hole including a screw seat arranged for fixing the abutment (1 ) to the dental implant via a dental screw (50).

11. A method of manufacturing an abutment (1 ), in particular according to any one of the preceding claims, the abutment comprising a coronal interface region (10), an apical interface region (20), and an intermediate region (30) in between the coronal interface region and the apical interface region, wherein the method comprises the steps: machining a flat contact surface (12) of the coronal interface region (10) connectable to a dental restoration; machining the apical interface region (20) having an apical interface axis (21 ) connectable to a dental implant; apically of the flat contact surface (12) of the coronal interface region machining a cylindrical section (31 ) of the intermediate region to a height of 0.25 mm or less and a tapering portion (32) tapering in the direction of the apical interface region (20).

12. The method according to claim 11 , wherein the apical interface region (20) is machined to have a first surface roughness and the intermediate region (30) is machined to have a second surface roughness, wherein the first surface roughness is lower than the second surface roughness.

13. The method according to claim 11 or 12, wherein the intermediate region is machined by milling and the apical interface region is preferably machined by turning.

14. The method according to any one of claims 11 to 13, wherein the surface of the abutment (1 ) is at least partially obtained by performing an anodic oxidation process.

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