Cheekbone dental implant

Abstract

The present invention relates to a cheekbone implant having an elongated profile, comprising: an elongated tip portion having a central longitudinal axis for anchoring the implant in the cheekbone of a patient; the crown end part is provided with an internal threaded hole, and the abutment can be meshed with the implant through the internal threaded hole; and an intermediate portion extending between the apical end portion and the crown end portion, the cross-sectional shape of the intermediate portion and / or the crown end portion being oval along a plane perpendicular to the central longitudinal axis.

Description

Technical Field

[0001] The present invention relates to a dental implant for restoration, in particular to a zygomatic bone implant. Technical Background

[0002] Zygomatic implants are longer than traditional dental implants and are often used in patients who have experienced jaw bone resorption and / or degeneration.

[0003] The zygomatic implants in the prior art generally have a cylindrical shape, which includes: a distal or apical portion that anchors the implant in the patient's zygomatic bone; a proximal or coronal portion having an angled platform, through which a structure such as an angled abutment is fixed; and a middle portion extending between the apical and coronal portions.

[0004] Certain existing zygomatic implant profiles have a relatively straight surface or side that engages the patient's soft tissue in an effort to reduce bulges that can cause soft tissue thinning (for better aesthetics). However, the addition of the straight surface results in sharper implant edges, particularly where the straight surface contacts the angled platform. Such sharp surfaces are known to intrude upon or irritate the patient's soft tissue, causing gingival irritation, leading to peri-implant atrophy and / or infection that can be difficult to treat. Additionally, the external threads of the apical portion may also dig into the patient's soft tissue.

[0005] To reduce the risk of atrophy and / or infection, surgeons can change the position and / or angulation of zygomatic implants to avoid buccal bio-invasion but may result in intrusion into medial spaces (such as the maxillary sinus or sublingual space); surgeons can also place implants on the palatal (and lateral) side of the dental arch, which can result in (1) difficulty in cleaning and subsequent risk of infection, (2) reduced restorative space, risk of fracture, and reduced durability, and (3) discomfort caused by bulky restorations and speech dysfunction.

[0006] While angled abutments can help correct angulation of zygomatic implants, they are often bulky and may increase patient discomfort and soft tissue invasiveness. Additionally, when angled abutments are used with angled platforms, the angle between the abutment and implant may become too sharp on one side, compromising the biological width and increasing the risk of shrinkage and / or infection.

[0007] To solve the above problems, it is necessary to provide one or more feasible alternatives. Embodiments of the present invention are intended to improve the aesthetics, biostability, cleanability, durability and / or patient comfort of zygomatic dental implants. Summary of the invention

[0008] According to a first aspect of the present invention, there is provided a zygomatic implant having an elongated shape, comprising:

[0009] an elongated apical portion having a central longitudinal axis for anchoring the implant in the patient's zygomatic bone;

[0010] a coronal portion having an internally threaded hole through which the abutment can engage with the implant; and

[0011] The middle portion extending between the apical portion and the coronal portion,

[0012] The middle portion and / or the crown end portion may be oval in shape in a cross section perpendicular to the central longitudinal axis.

[0013] The oval cross-sectional shape may be formed by the intersection of a first curved line and a second curved line of different lengths.

[0014] The first curve may include a first arc segment having a first diameter, and the second curve may include a second arc segment having a second diameter (different from the first diameter). In some embodiments, the perimeter of the oval cross-section is primarily defined by the first arc segment.

[0015] Moving in the coronal direction, the perimeter of the oval cross-section may be increasingly defined by a second arc segment.

[0016] The oval cross-section is expected to include an axis of symmetry passing through respective centers of the first arc segment and the second arc segment.

[0017] In at least one embodiment, the central longitudinal axis lies in a plane that bisects the top portion, and it is contemplated that the axis of symmetry of the lower end of the middle portion is generally perpendicular to the plane.

[0018] When moving in the coronal direction, the axis of symmetry may become increasingly acute relative to the plane bisecting the apical portion. In addition, the center of the second arc segment may be rotated up to 90 degrees around the central longitudinal axis.

[0019] The coronal portion may include a flat platform that is generally planar and faces the direction of the center of the second arc segment at the upper end of the coronal portion. In at least one example, the platform is angled with a plane perpendicular to the central longitudinal axis. For example, the implant may be angled about 35° to 45° with a plane perpendicular to the central longitudinal axis.

[0020] It is expected that the center hole axis of the internally threaded hole is usually perpendicular to the flat platform.

[0021] In certain embodiments:

[0022] The first arc segment forms a portion of a first circle having a first diameter; and

[0023] The second arc segment forms a portion of a second circle having a second diameter, the second diameter being greater than the first diameter by a predetermined numerical factor.

[0024] In at least one instance, the first arc segment and the second arc segment intersect at an intersection of a pair of identical third circles, the third circles are spaced apart from each other and contained within the first circle, and have a third diameter, which is the square root of a predetermined numerical factor, and is tangent to the first circle and the second circle.

[0025] It is contemplated that the predetermined numerical factor may be approximately between 1 and 2. For example, the predetermined numerical factor may be approximately between 1.5 and 1.7.

[0026] In some embodiments, the top portion includes an external thread and a smooth non-threaded head portion. In at least one example, the upper end of the smooth head portion is inclined upward from the top portion first side around its circumference to the opposite second side of the top portion, thereby defining the top of the smooth head portion.

[0027] It is expected that the slope of the upper end of the smooth head portion is about 10° to 60° relative to the central longitudinal axis. In some embodiments, it is about 35°. It is expected that the vertex of the smooth head portion is aligned with the center of the second arc segment of the upper end of the crown end portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings wherein:

[0029] Figure 1 is a perspective view of a zygomatic bone implant according to an embodiment of the present invention;

[0030] Figure 2A for Figure 1 Right side view of the implant;

[0031] Figure 2B for Figure 1 Frontal view of the implant;

[0032] Figure 3A for Figure 1 Left side view of the implant;

[0033] Figure 3B for Figure 1 Posterior view of the implant;

[0034] Figure 4A for Figure 1 Top view of the implant cross section taken along AA;

[0035] Figure 4B for Figure 4A Schematic diagram of the geometric shape;

[0036] Figure 5A for Figure 1 Top view of the implant cross section taken along BB;

[0037] Figure 5B for Figure 1Top view of the implant cross section taken along CC;

[0038] Figure 6 To observe from the inner hole alignment direction Figure 1 View of the implant;

[0039] Figure 7 for Figure 1 Top view of the implant;

[0040] Figure 8 for Figure 1 Close-up of the implant's angled platform; and

[0041] Fig. 9 For Figure 6 The same view shows the top of the smooth head portion aligned with the buccal surface of the implant's upper end. DETAILED DESCRIPTION

[0042] Figures 1 to 3A Various views of a zygomatic implant 2 according to an embodiment of the present invention are shown; the implant 2 has a generally elongated and integrally formed profile 4, including a distal or apical portion 6 for anchoring the implant 2 in the zygomatic bone of a patient. The elongated profile 4 also includes a proximal or coronal portion 8 having an angled platform 10, and a structure such as an abutment can be secured to the implant 2 via an internally threaded hole 12 formed at the upper end of the coronal portion 8. The elongated profile 4 also includes an intermediate portion 14 extending between the apical portion 6 and the coronal portion 8.

[0043] The tip portion 6 may have external threads 16 and / or grooves 18, which may be used to anchor the tip portion 6 in the patient's zygomatic bone. The tip portion 6 may also have a polished, smooth, non-threaded tip portion 20 that may taper slightly outward (e.g., increase in diameter) as one moves in the direction of the coronal portion 8. In the depicted embodiment, the tip portion 6 is generally symmetrical about two planes and defines a central longitudinal axis extending through the length of the body. The central longitudinal axis is at Figures 2A to 3B and Figure 8 Although the top portion 6 has two symmetry planes, in the described embodiment, these planes do not symmetrically divide the middle portion 14 and / or the coronal portion 8. As will be discussed later, in some embodiments of the present implant 2, the middle portion 14 and / or the coronal portion 8 are not symmetrically distributed on the central longitudinal axis XA of the top portion 6.

[0044] The middle portion 14 of the implant 2 smoothly merges into the coronal portion 8, and the two portions 8, 14 together define a first outer curved surface 22 and a second outer curved surface 24 of the elongated implant 2. When implanted, the second curved surface 24 engages the patient's soft tissue, so the second curved surface 24 is also called the buccal surface 24.

[0045] Unlike existing implants with generally straight or flat surfaces (for contacting the patient's soft tissue), the present implant 2 includes a curved buccal surface 24. Compared to a generally straight surface, the curved buccal surface 24 disclosed in the present invention can smoothly and gradually blend or form a contour with the angled platform 10 of the coronal portion 8 of the implant 2, thereby reducing the sharpness of any edge at the interface between the buccal surface 24 and the flat platform 10. The implant 2 disclosed in the present invention can eliminate or at least reduce the roughness and sharpness of such edges, provide better patient comfort, and reduce the possibility of irritation, infection, etc.

[0046] Also refer to Figure 4A The curvature of the buccal surface 24 is different from the curvature of the first curved surface 22 of the implant 2. On the contrary, the curvature of the buccal surface 24 is smaller than the curvature of the first curved surface 22 (ie, the curvature is smaller). Figure 4A The lower end of the middle portion 14 is shown along a plane AA (see FIG. Figure 2A ) is a cross-sectional shape OXA taken from the middle portion 14. It can be seen that the cross-sectional shape OXA of the middle portion 14 is generally oval and is formed by the intersection of a first curve 26 and a second curve 28 of different lengths. Unless otherwise specified, the term "oval" herein refers to an ellipse.

[0047] Also refer to Figure 4A , the first curve 26 defines the curvature of the first curved surface 22 of the implant 2, and the second curve 28 defines the curvature of the buccal surface 24 of the implant 2. In the embodiment, the first curve includes a first arc segment 26 having a first diameter Di, and the second curve includes a second arc segment 28 having a second diameter D2 (greater than the first diameter Di). The ends of the two arc segments 26 and 28 intersect at a predetermined position ( Figure 4A The buccal surface 24 is formed by a plurality of curved surfaces 26a and 26b, and a plurality of curved surfaces 28a and 28b are formed by a plurality of curved surfaces 26c and 28c. The buccal surface 24 is formed by a plurality of curved surfaces 26c and 28b, and a plurality of curved surfaces 26c and 28b are formed by a plurality of curved surfaces 26c and 28b ...

[0048] Figure 4B How to derive Figure 4A Schematic diagram of OXA with medium oval cross-sectional shape. First, Figure 4B A first circle Ci is shown, the diameter of which corresponds to the first diameter Di of the first arc segment 26 (defining the first curved surface 22 of the implant 2). Figure 4BAlso shown is a second, larger circle C2 that overlaps the first circle Ci. The diameter D20f of the second circle C2 is greater than the diameter of the first circle C1 by a predetermined numerical factor and corresponds to the second diameter D20f of the second arc segment 28, and therefore corresponds to the arc of the buccal surface 24. Although the arc 24 of the buccal surface is shown as an arc segment with a constant diameter, it can also be formed by an arc segment whose diameter varies along the length of the implant 2.

[0049] Figure 4B , the second circle C2 is aligned with, overlaps with and intersects the first circle Ci at two points; these two intersection points define the intersection point Mp of the first arc segment 26 and the second arc segment 28 mentioned above. Figure 4B Also shown is a pair of equal, spaced-apart third circles C3 contained within the first circle Ci. The third circle Cs is proportionally smaller than the first circle Ci and the second circle C2. In the described embodiment, the third circle diameter Cs is approximately smaller than the first circle diameter Ci by the square root of the above-mentioned predetermined numerical factor. Therefore, the diameter of the third circle C3 is smaller than the diameter of the second circle C2 by the cube root of the predetermined numerical factor. It can be seen that the second circle C2 intersects with the first circle C1 at the position where the third circle C3 is tangent to the first circle C1 and the second circle C2. Of course, the second circle C2 may intersect with the first circle Ci at other positions (for example, by embedding the third circle Cs to varying degrees within the first circle Ci). For example, referring to Figure 4B , the third circle C3 can be further moved to the right or left within the first circle Ci to change the position where the first circle Ci and the second circle C2 intersect, thereby determining the structure 24 of the buccal surface. In fact, the structure of the buccal surface 24 can be changed as needed to adapt to the needs of the patient, better ensuring a relatively smooth transition between the first curved surface 22 and the buccal surface, thereby avoiding or reducing any sharp edges.

[0050] Figure 4B A method of determining the configuration of the buccal surface 24 is briefly described, although other methods may be used to determine its curved configuration. Thus, the present description includes within its scope any number of differently configured zygomatic implants 2 in which the intermediate portion 14 and / or the coronal portion 8 have an oval cross-sectional shape OXA, preferably defined by the intersection of two different curves or arc segments. Figure 4B , the predetermined numerical factor by which circles of different sizes Ci, C2, C3 are proportional to each other is approximately 1.618 (also known as the golden ratio), although other predetermined numerical factors (e.g., any factor between 1 and 2) may also be applied. Of course, the predetermined numerical factors do not need to be consistent between all circles Ci, C2, C3. For example, the numerical factors of the first circle Ci and the second circle C2 do not need to be related to the numerical factors of the first circle Ci and the third circle C3, etc.

[0051] Although the drawings illustrate a generally asymmetrical zygomatic implant 2, the scope of the present description also includes zygomatic implants 2 having at least one plane of symmetry. For example, certain implant embodiments may include a middle portion 14 and a coronal portion 8 that include a generally constant oval cross-section. In such implants, the oval cross-sectional shape remains relatively constant as one moves upward along the length of the implant 2 toward the coronal portion 8. As will now be discussed, the oval cross-sectional shape Ox of the implant 2 shown in the drawings is not constant, but rather varies along the length of the middle portion 14 and the coronal portion 8.

[0052] Reference Figure 2B , moving upward from the lower end of the middle portion 14 in the direction of the coronal portion 8, it can be seen that the buccal surface 24 increases in size and becomes increasingly deviated from or out of alignment with the central longitudinal axis XA. In other words, if a lateral line is drawn from one side of the curved buccal surface 24 to the other side, the line will become longer and more deviated from the central longitudinal axis XA in the direction of the coronal portion 8. This can be seen by comparing Figure 2B The lateral extension lines (indicated as LA and Lc) in the figure can be seen. Figure 4A , 5A As can be seen from Figures 5B and 5B, this movement or twisting of the buccal surface 24 along the length of the implant 2 is also evident.

[0053] 4A, Figure 5A and Figure 5B Each shows a vertical plane extending through and bisecting the top portion, labeled PB. Figure 4A As can be seen in FIG. 1 , the axis of symmetry Xsym extending through the oval cross-sectional shape OXA is generally perpendicular to the bisecting plane PB.

[0054] Figure 5A and 5B The implant 2 coronal portion 8 is shown along Figure 2A Oval cross-sectional shapes OXB and OXC in the BB and CC planes. Compare Figure 5A and Figure 4A It can be seen that Figure 5A The center 28c of the second arc segment 28 and the symmetry axis Xsym are rotated or moved counterclockwise relative to the bisecting planes PB and SO, thereby forming an acute angle Qi. Further moving in the direction of the crown end portion 8, an oval cross-sectional shape Oxc taken at CC is achieved, as shown in FIG. Figure 5BAs shown, the center 28c of the second arc segment 28 and the symmetry axis Xsym passing therethrough rotate or move to form a larger acute angle θ2 with the bisecting plane PB. In other words, moving toward the coronal portion 8, the size of the second arc segment 28 becomes larger, and the position gradually twists in the counterclockwise direction. In this way, although the circumference of the oval cross-sectional shape Ox is mainly defined by the length of the first arc segment 26, when going up along the implant 2 to the coronal portion 8, the circumference is gradually defined by the length of the second arc segment 28. In other words, relative to the first curved surface 22 of the implant 2, the size of the buccal surface 24 increases in the direction of the coronal portion 8.

[0055] In the embodiment described, it is expected that the symmetry axis Xsym of the oval cross-sectional shape Ox is oriented toward the top of the coronal portion 8 or at the coronal portion 8 (eg Figure 5B ), relative to its original orientation (e.g. Figure 4A ) is twisted or rotated counterclockwise by about 22.5 degrees. Of course, rotations of up to 90 degrees are within the scope of this specification. This changed configuration of the curved cheek surface 24 and the associated movement of the center 28c of the second arc segment 28 along the middle portion 14 and the crown end portion 8 is caused by Figure 6 The dotted line LB is shown in FIG. Draw the dotted line LB so that it passes through the center BA of the lower curved cheek 24 of the middle part (corresponding to the center of the second arc segment 28 at this position) and the center Bc of the upper curved cheek 24 of the crown end part 8; it can be seen that the dotted line LB is slightly angled relative to the vertical direction.

[0056] Also refer to Figure 6 , the planar platform 10 of the coronal portion 8 and the associated internal threaded hole 12 are oriented to be aligned with the center of the second arc segment 28 of the oval cross-sectional shape Ox at or toward the top of the coronal portion 8 (i.e., the position indicated by Bc). In other words, the threaded hole 12 is generally aligned with the symmetry axis Xsym of the buccal surface 24 toward the upper end of the coronal portion 8. The alignment of the threaded hole 12 with the symmetry axis Xsym can also be seen Figure 7 . This causes the platform 10 and the hole 12 to twist slightly in a counterclockwise direction, which helps to correct or compensate for the angle of the zygomatic implant 2 so that it is in the original position and the hole 12 is closer to or in the direction and position required for the attachment (e.g., abutment) to occlude. Of course, the degree of twisting of the buccal surface 24 and the inner hole 12 about the central longitudinal axis XA may vary and may be customized to the specific patient, which may help reduce or eliminate the need for an angled abutment, thereby allowing a smaller volume abutment and similar abutments to occlude with the implant 2 of the present invention.

[0057] Reference Figures 1 to 3B , Figure 6 and Fig. 9The implant 2 comprises a smooth, threadless head portion 20, which is asymmetrically distributed on the central longitudinal axis XA. In the embodiment, the polished, smooth head portion 20 is approximately a sphere, and in particular, its upper end is expected to be cut into a prolate sphere by an angled plane. Figure 3A , plane Ps passes through and defines the upper end of the smoothing head portion 20, at an angle relative to the central longitudinal axis XA. In the illustrated embodiment, plane Ps is at an angle of approximately 35°03 with the longitudinal axis XA, although the angle may vary. In this manner, the upper end of the smoothing head portion 20 includes a lowermost first end that coincides with a first side of the tip portion 6 and an uppermost second end that coincides with an opposite side of the tip portion 6 (defining the uppermost second end of the top or tip 20A of the polishing head portion 20).

[0058] Reference Fig. 9 , it can be seen that the top or apex 20A of the polishing head portion 20 is aligned with the center of the second arc segment Bc at the upper end of the coronal portion 8. In other words, the top 20A of the polishing head portion 20 and the center of the second arc segment Bc at the upper end of the coronal portion 8 are substantially located on the same vertical axis. It should be noted that in the embodiment described, the vertical axis is not coincident with the central longitudinal axis XA of the apical portion 6, but is parallel thereto. However, the scope of this specification certainly includes embodiments in which the above axes may coincide.

[0059] The smooth angled head portion 20 disclosed in the present invention is configured to provide a larger polishing surface area on one side (corresponding to the side with the top 20A) than on the opposite side. When implanted, this larger polishing surface area is configured to occlude the patient's soft tissue and reduce the possibility that the external thread 16 of the top portion 6 contacts, occludes or otherwise irritates the patient's soft tissue. Advantageously, when the direction of the top 20A (and therefore the larger surface area of ​​the polishing head 20) is aligned with the center of its upper buccal surface 24, the implant 2 of the present invention can improve the orientation and occlusion of the smooth buccal surface 24r and the polishing head 20 with the patient's soft tissue, thereby reducing the risk of irritation and / or infection.

[0060] Although the embodiment shows that the buccal surface 24 of the implant 2 is twisted, turned or rotated in a counterclockwise direction, the buccal surface 24 can also be twisted, turned or rotated in the opposite clockwise direction. In this way, the implant of the present invention can be manipulated to make it more comfortable and suitable for the left or right hand side of the patient's face. For example, an implant with a counterclockwise twisted curved buccal surface may be more suitable for the right side of the patient's face (looking at the patient's face) and more comfortably occlude the soft tissue, while a clockwise twisted buccal surface may be more suitable for the opposite side.

[0061] In other embodiments, as previously described, the scope of the present specification also encompasses implants 2 in which the oval cross-section Ox remains relatively constant along the length of the implant 2. In certain examples of such embodiments, particularly where the implant 2 includes rotation of the coronal platform 10 and associated aperture 12, it can be expected that the symmetry axis Xsym point remains relatively constant along the length of the implant 2 until at or toward the upper end of the coronal portion 8 closer to the top of the buccal surface 24 (the symmetry axis Xsym can thus be twisted about the longitudinal axis XA), allowing rotation of the coronal platform 10 and aperture 12, as previously described.

[0062] Those skilled in the art may make various adjustments to the above embodiments within the scope of the present invention. For example, the configuration of the curved buccal surface may vary and may be customized to the needs of a particular patient. For example, the curvature of the buccal surface may be larger, smaller, deviate from the bisecting plane to varying degrees, and vary in how gradually it is twisted (if at all), etc. Figure 8 The planar platform 10 of the coronal end portion 8 is shown to be at an angle of approximately 45 to 55 degrees to the central longitudinal axis XA (or 35 to 45 degrees to the vertical plane), although the angle of the platform 10 can be varied as desired. Figure 8 It is also shown how the central axis Bx of the threaded hole is generally perpendicular to the plane of the planar platform 10 .

[0063] Although the figures depict the coronal end portion 8 having a groove extending circumferentially along the first curved surface 22 (ie, on the side opposite the buccal surface), such a groove is optional and the surface may be smooth in nature.

[0064] Thus, embodiments of the present implant may have a softened buccal contour to more harmoniously fit the patient's bone envelope. Additionally, the offset platform and internal bore rotation may help improve implant positioning and reduce reliance on angled abutments.

[0065] In this specification and the appended claims, unless the context requires otherwise, the term "comprise" and its synonyms such as "comprising" and "containing", will be understood to imply the inclusion of stated integers or steps or integers or groups of steps but not the exclusion of any other integers or steps or integers or groups of steps.

[0066] Reference in this specification to any previous publication (or information obtained therefrom) or any known content is not and should not be regarded as a confirmation or acknowledgement or any form of implication that the previous publication (or information obtained therefrom) or known content constitutes part of the common general knowledge in the field relevant to this specification.

Claims

1. A zygomatic implant with a slender shape, It is characterized in that include: Slender tip for anchoring implants in the patient's zygomatic bone an apical portion having a central longitudinal axis; a coronal portion having an internally threaded hole through which the abutment can engage with the implant; and The middle portion extending between the apical portion and the coronal portion, The middle portion and / or the crown end portion may be oval in shape in a cross section perpendicular to the central longitudinal axis.

2. The implant according to claim 1, It is characterized in that The oval cross-sectional shape is formed by the intersection of a first curved line and a second curved line of different lengths.

3. The implant according to claim 2, It is characterized in that The first curve includes a first arc segment having a first diameter, and the second curve includes a second arc segment having a second diameter (different from the first diameter).

4. The implant according to claim 3, It is characterized in that The perimeter of the oval cross-sectional shape is primarily defined by the first arc segment.

5. The implant according to claim 4, It is characterized in that Moving in the coronal direction, the perimeter of the oval cross-sectional shape is increasingly defined by a second arc segment.

6. The implant according to claims 3 to 5, It is characterized in that The oval cross-sectional shape includes an axis of symmetry passing through respective centers of the first arc segment and the second arc segment.

7. The implant according to claim 6, It is characterized in that The central longitudinal axis lies in a plane bisecting the top portion, and the axis of symmetry of the lower end of the middle portion is generally perpendicular to the plane.

8. The implant according to claim 7, It is characterized in that Moving in the coronal direction, the axis of symmetry becomes increasingly acute relative to the plane bisecting the apical portion.

9. The implant according to claim 8, It is characterized in that When moving in the coronal direction, the center of the second arc segment can rotate up to 90 degrees about the central longitudinal axis.

10. The implant according to claim 8 or 9, It is characterized in that The coronal end portion includes a generally planar platform facing a direction aligned with the center of the second arc segment at the upper end of the coronal end portion.

11. The implant according to claim 10, It is characterized in that The platform is at an angle to a plane perpendicular to the central longitudinal axis.

12. The implant according to claim 11, It is characterized in that The implant is at an angle of approximately 35° to 45° to a plane perpendicular to the central longitudinal axis.

13. The implant according to claims 10 to 12, It is characterized in that The central hole axis of the internal threaded hole is usually perpendicular to the planar platform.

14. The implant according to claims 3 to 13, Features: The first arc segment forms a first circle having a first diameter; and The second arc segment forms a second circle having a second diameter, which is greater than the first diameter by a predetermined numerical factor.

15. The implant according to claim 14, It is characterized in that The first arc segment and the second arc segment intersect at a pair of identical third circle intersection points, the third circles are spaced apart from each other and contained within the first circle, have a third diameter of the square root of the predetermined numerical factor, and are tangent to the first circle and the second circle.

16. The implant according to claim 14 or 15, It is characterized in that The predetermined numerical factor is approximately between 1 and 2.

17. The implant according to claims 14 to 16, It is characterized in that The predetermined numerical factor is approximately between 1.5 and 1.

7.

18. An implant according to the preceding claim, It is characterized in that The top portion includes external threads and a smooth, non-threaded head portion.

19. The implant according to claim 18, It is characterized in that The upper end of the smooth head end portion is inclined upward from the first side of the top end portion around its circumference to the opposite second side of the top end portion, thereby defining a top end of the smooth head end portion.

20. The implant according to claim 19, It is characterized in that The angle is approximately 10° to 60° relative to the central longitudinal axis.

21. An implant as claimed in claim 19 or 20 (attached to claims 6 to 13), It is characterized in that The top end of the smooth head end portion is aligned with the center of the second arc segment at the upper end of the crown end portion.

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