Bone adjustment implant

Abstract

An implant for screwing into a living bone preparation hole has a body extending between a root tip and a crown end. A thread is helically wound along the body. The thread is provided with a truncated crest, a plurality of chip groove sections are formed on the crest, and the chip groove sections jointly form a group of chip grooves. The truncated crest also supports a set of compression ramps configured to apply a compressive stress to an inner surface of the bore with a densification effect when the implant is screwed into the bore. The root tip has a pair of cutting edges radially opposed to each other. Each cutting edge is formed between the plough cutting face and the supporting face. And a micro chamfer is arranged on the supporting surface close to the cutting edge. And a valley is arranged at the root tip end. The valley enables the bottom of the hole to form a substantially circular bone column.

Description

Related Applications

[0001] This application claims priority to U.S. Provisional Patent Application Nos. 63 / 489,233, filed March 9, 2023, and 63 / 498,444, filed April 26, 2023, the entire disclosures of which are incorporated herein by reference and relied upon. TECHNICAL FIELD

[0002] The present invention relates generally to implants intended to provide a fixation function in a host material, more particularly to implants intended to induce new bone ingrowth and bone bonding and to improve stability, even more particularly to such implants placed in living organic material, such as bone. BACKGROUND

[0003] Twist-in implants are widely used. For example, in industrial and construction environments, when the host material is wood, concrete, metal or a polymer, an implant can be placed to provide a fixed connection point to connect another element. Twist-in implants are widely used in medical applications, where the host material is bone, for providing a fixed connection point for metal plates, steel needles, rods, K-wires, and intramedullary devices such as Küntscher pins and locking intramedullary nails, among many others.

[0004] Dental implants are another form of twist-in implants, with the host material being bone. Dental implants, also known as endosseous implants or fixtures, are surgical devices used to support crowns, bridges, dentures, facial prostheses, or to act as orthodontic implants. Typically, such implants are designed as threaded, conical implants that can be loaded immediately after placement so that over time, as the surrounding bone grows into the interstices and around the implant, full stability (i.e., secondary stability) can be achieved, a process known as osseointegration. Bone ingrowth can take months of time until the implant reaches a sufficient (secondary) stability to be put into normal load service.

[0005] In many applications, the stability of the implant is a key consideration, as the implant must be able to support the expected load. When the host material is non-organic living tissue (as is the case with foams and metals), maximum implant stability is typically achieved immediately after placement. For these cases, the design of the implant should maximize the initial stability, also known as primary stability. In applications where the host material is organic living material (such as bone or wood), full implant stability can take time to achieve as the implant undergoes healing and ingrowth after placement. In the latter case, the faster the implant reaches a sufficient level of secondary stability is desirable.

[0006] Implants that are sufficiently stable at the time of initial implantation are of great value. Despite the large number of different designs and concepts in the prior art that aim at improving the stability of implants, including initial stability and secondary (long-term) stability, there is still a desire for improvement. In particular, the stability of implants is still a long-standing need in the art, where any improvement would be welcome. Furthermore, there is a need for an improved implant to promote bone integration at the apical (root tip) end. SUMMARY

[0007] According to one embodiment of the present application, a screw-in implant is provided. The implant includes a body extending longitudinally along a central axis between an apical end and a coronal end. The body has an apical region extending from the apical end and a coronal region extending from the coronal end, with a central region of the body located between the apical region and the coronal region. At least one thread protrudes from the body and spirally winds along the body from the apical region to the coronal region in a continuous winding. The thread has crests. Portions of the body located between adjacent windings of the thread constitute roots. The central region includes a set of flutes. Each flute extends longitudinally along the central region and is comprised of a plurality of individual and discrete flute segments. The discrete flute segments are formed in the crests of the thread. The central region further includes a set of compression ramps. Each compression ramp is disposed along the crest of the thread between two circumferentially adjacent flute segments. Each compression ramp has a low leading edge and a high trailing edge in a right-hand direction. The apical end has at least one cutting edge. The cutting edge has a generally radially extending edge formed between a plowing surface and a support surface.

[0008] The unique shape of the apical end with the cutting edge enables the implant to scrape and cut host material as it is screwed into the prepared hole. As the apical end descends toward the bottom of the hole, host material particles (e.g., bone chips) released by the cutting edge will accumulate around the apical end. These shed bone chips can act as seeds for bone growth promoters, thereby promoting ingrowth of new bone and bone integration. The multi-faceted shape of the apical end significantly increases the contact area of the bone with the implant, thereby improving stability. BRIEF DESCRIPTION OF DRAWINGS

[0009] These and other features and advantages of the present application will become more apparent from the following detailed description and accompanying drawings, in which:

[0010] Figure 1 is a cross-sectional view of a human mandible with a fully seated implant according to one embodiment of the present application;

[0011] Figure 2 is Figure 1 is an elevation view of the implant of

[0012] Figure 3 is a cross-sectional view of a human mandible with a fully seated implant according to one embodiment of the present application; Figure 2Same view, but highlighting the various tapers of the body / roots and the taper of the thread crest;

[0013] Figure 4 is Figure 2 a partial view of the implant in the middle, but highlighting the offset between the thread crest and the intermediate root;

[0014] Figure 5 is Figure 4 the same view, but highlighting the thread thickness and pitch;

[0015] Figure 6 is Figure 2 an apical end view of the implant in the middle;

[0016] Figure 7 is a perspective view of the apical end;

[0017] Figure 8 is Figure 7 another perspective view of the apical end, presented from a slightly different angle;

[0018] Figure 9 shows Figure 2 the implant in the middle partially inserted into a prepared hole;

[0019] Figure 10 is Figure 9 the same view, but showing the implant fully seated in the prepared hole;

[0020] Figure 11 is Figure 10 a magnified view of the area encircled by reference numeral 11 in the middle;

[0021] Figure 12 is an elevational view of the implant according to an alternative embodiment;

[0022] Figure 13 is Figure 12 a partial perspective view of the apical end of an alternative implant in the middle;

[0023] Figure 14 is Figure 12 a complete perspective view of the alternative implant in the middle; and

[0024] Figure 15 shows Figure 12 the implant in the middle fully seated in the prepared hole. DETAILED DESCRIPTION

[0025] With reference to the drawings, in which like numerals indicate like or corresponding parts throughout the several views, the present application will be described in the context of a dental implant, in which an osteotomy preparation needs to be made in the jawbone to receive a bone implant (1) having a threaded shaft (2) and an apical end (3) with a conical shape. Figure 1). It should be understood that the present invention is not limited to dental applications, but can be applied in various orthopedic fields. Moreover, the present invention is not limited to use in bone. The present invention can be used for implantation in living trees and other living cellular materials, as well as in metal foams and other non-living cellular host materials for various industrial and commercial applications, and the like. Dental applications, however, represent a convenient example, and the following description will be illustrated using the dental context of bone as the host material.

[0026] In Figure 1 , a toothless jaw site is shown in cross-section with an implant 20 according to one embodiment of the present invention implanted therein. Implant 20 is of the type that can be screwed into a prepared hole in the host material. When the host material is bone, the prepared hole is referred to as an osteotomy hole.

[0027] The prepared hole or osteotomy hole can be formed using any suitable technique. One such technique includes the use of a progressively wider rotary osteotome that is specifically configured to achieve osteo-densification along the surrounding bone wall. The process of forming an osteotomy hole using a progressively wider rotary osteotome is generally described in Huwais’ U.S. Patent No. 9326778, issued May 3, 2016. Reference can also be made to U.S. Patent No. 10980548, issued April 20, 2021. The entire contents of these documents are incorporated herein by reference and relied upon in all jurisdictions where such incorporation by reference is recognized.

[0028] Once the osteotomy hole is ready, implant 20 is again screwed into place by any suitable technique, as shown in Figure 1 , in the customary right-hand thread direction. According to well-known practice, an abutment (not shown) is eventually screwed into the internal connecting portion, thereby being secured in place to receive a subsequent restoration or crown (also not shown). Implant 20 can be well suited for placement in bone, but non-bone applications are also possible. Again, while the illustrated embodiment describes implant 20 in the form of an implant or receiver for a dental restoration, it must be understood that implant 20 can be reconfigured as a bone screw or other bone fixation element, such as can be used in spinal, hip, shoulder, wrist, and other orthopedic applications, as well as implants for various non-medical applications.

[0029] Implant 20 can be designed to fit prepared holes of different diameters. While not shown, implant 20 of different lengths and diameters suitable for prepared holes of different depths and diameters are likewise possible. Those skilled in the art will understand that the principles of the present invention can take many different forms without departing from the spirit of the teachings. Based on this understanding, the present invention will be described in the context of a general example as described in Figures 2-11

[0030] With specific reference now to Figure 2 and​Figure 3 Implant 20 includes a frusto-conical body having a tapered outer profile. The body of implant 20 extends longitudinally along a central or longitudinal axis A. The body has an apical end 22 and a coronal end 24. The terms "apical" and "coronal" are chosen primarily because of their dental relevance. "Apical" refers to a direction toward the apical end of a tooth; "coronal" refers to a direction toward the coronal end of a tooth. The use of these terms, and other terms herein, by the Applicant should not be construed as limiting the application of implant 20 to the field of dental use, or even to the field of medical use. Coronal end 24 is preferably flat or substantially flat and serves as a platform for dental restoration or other subsequent attachment to implant 20. Apical end 22 forms the leading end of implant 20, which is first inserted into a prepared osteotomy hole in use. Apical end 22 includes a number of unique features, which will be described in detail below.

[0031] Implant 20 has an apical region 26 proximate apical end 22 and a coronal region 28 proximate coronal end 24. Apical region 26 represents a portion of the body extending from apical end 22. Likewise, coronal region 28 represents a portion of the body extending from coronal end 24. A central region 30 of the body extends between apical region 26 and coronal region 28. Central region 30 is continuous with both apical region 26 and coronal region 28 at both ends, such that in the illustrated example, the three regions 26, 28, 30 completely occupy the entire longitudinal length of the body from apical end 22 to coronal end 24.

[0032] In Figure 3 It can be readily seen in that the outermost surface of the body has a tapered profile. In particular, the various regions 26, 28, 30 can be distinguished from one another by a number of factors, including the characteristics of the taper of the body. It is therefore readily understood that the body is described as having an apical taper Rl throughout apical region 26, a coronal taper R3 throughout coronal region 28, and a central taper R2 throughout central region 30.

[0033] Apical taper Rl as measured from central axis A can be between about 2°-30°. In some embodiments, apical taper Rl can be between 7°-18°. The illustrated example depicts an apical taper Rl in the range of 10°-15°. It is noted that the taper angle herein is measured from central axis A, which is understood to be a half-angle; the full taper taper is twice the given measurement.

[0034] Central taper R2 as measured from central axis A can be between about -5° to +15°. As can be seen from the negative lower limit of the range, it is contemplated that central taper R2 can form a reverse taper. However, in most embodiments, the lower limit of central taper R2 is expected to be non-negative, as in a more limited range of about 0°-10°. The illustrated example depicts a central taper R2 in the range of 0°-5°.

[0035] The coronal taper R3, measured from the central axis A, can be between about 5° and 35°, more particularly between 10° and 25°. In some embodiments, the coronal taper R3 can be between about 15° and 20°.

[0036] In bone applications, these ranges can represent critical limits, as going beyond the range limits can result in too little or too much radial compression. The apical taper Rl and the coronal taper R3 need not be substantially equal, i.e., match each other. For some dental applications and some non-dental bone applications, a somewhat larger taper range can be desirable. For non-medical applications, a larger taper range can be contemplated.

[0037] In actual applications, the longitudinal lengths of the apical region 26, the coronal region 28, and the central region 30 can vary relative to the overall longitudinal length of the body and the associated taper angles Rl, R2, and R3. For example, in the illustrated embodiment, if the longitudinal length of the apical region 26 is designated as one unit, then the central region 30 is about 1 1 / 3 units in length, and the coronal region 28 is about 1 3 / 4 units. With these rough measurements, the overall longitudinal length of the body is just over 4 units. Naturally, the relative lengths of the apical region 26, the coronal region 28, and the central region 30 are highly adaptable to accommodate the intended application. That is, these dimensional relationships can be varied to accommodate the application and / or to achieve particular performance attributes. For example, the apical region 26 can be relatively lengthened or shortened; the coronal region 28 can be relatively lengthened or shortened, and the central region 30 can be relatively lengthened or shortened. Of course, many further alternatives will become apparent to those skilled in the art. While the relative lengths can vary, the external shape of the body should maintain a generally conical taper (i.e., Rl, R2, R3) that, on average, increases toward the coronal end 24. The tapered geometry is believed to contribute to achieving superior initial stability and load profiles. However, the present application can be implemented in a completely straight and nearly straight implant geometry and is expected to be successful. Thus, the principles of the present application are not limited to implant designs having only conical geometry.

[0038] As is known in the art, an internal tool sleeve is provided in the body, opening directly from the coronal end 24. The tool sleeve can extend through the coronal region 30 and into the central region 30. The tool sleeve can take the form of an internal hex recess for coupling with a matingly shaped driver head. Of course, the form of the tool sleeve will be matched to the particular application and to the standards of the relevant industry / field of use. The tool sleeve is designed as a through structure, enabling access to a recessed threaded portion. This threaded portion is adapted for connection with an abutment or other component that is subsequently installed onto the implanted implant 20.

[0039] As shown in various views, at least one thread 32 protrudes from the body. The phrase "at least one" is used to emphasize that in some contemplated embodiments, the implant 20 can be configured with a dual-lead thread or even a triple-lead thread 32. However, in the example shown, the thread 32 is a single-lead thread that continuously spirals from the apical region 26, through the entire central region 30, and all the way to the coronal region 28. In most contemplated applications, the thread 32 will be wound around the body in a right-handed direction, according to the most common convention. Of course, if a specific application dictates a preference for left-handed winding, then a complete mirror image of the implant 20 is expected to perform a similar function.

[0040] As is common in threaded fasteners and threaded mechanisms, the thread 32 has a crest 34 at the top of its front and rear sides. For clarity, the front side refers to the spiral surface of the thread 32 facing the root tip 22, and the rear side refers to the spiral surface of the thread 32 facing the crown end 24. If the front and rear sides of the thread 32 are fully extended, they will meet to form a sharp edge, thereby forming a knife-like crest. However, in this case, the crest 34 is truncated or ground. In the example shown, the crest 34 has a certain thickness, which can be measured at any position in its axial or longitudinal direction. As will be described later in conjunction with Figure 5 As described, the thickness of the crest 34 can be configured to impart active functionality and novel properties to the implant 20 .

[0041] exist Figure 3 In the embodiment, the tooth tops 52 are arranged in a generally conical shape, which can be seen by a generally common tooth top taper C. The tooth top taper C can be any suitable angle. In some embodiments, the tooth top taper C can be between about 1° and 15° as measured from the central axis A. Figure 3 In the example shown, the tooth top taper C is in the range of 3-4°, which has been shown to provide satisfactory results.

[0042] According to standard thread terminology, the thread 32 has a minor diameter defined by the body and a major diameter defined by the crest 34. The portion of the body between adjacent turns of the thread 32 constitutes the root. The minor diameter corresponds to the root diameter of the thread 32. Figure 4 At any position on the thread 32, the difference between the minor diameter and the major diameter can be measured as the offset 36 between the crest 52 and the root or body of the implant 20. Figure 4 In the figure, offset 36 is indicated as a whole by a dashed line and a vector, rather than by individual annotations. Therefore, along the winding path of thread 32, offset 36 can be measured radially from the crest 34 to the root. A careful observation reveals that at any position along thread 32, offset 36 on the trailing flank is often different from offset 36 on the leading flank.

[0043] As previously mentioned, the thread 32 has a thread thickness. The thread thickness refers to the axial dimension between the leading flank and the trailing flank as measured at the crest 34. The thread thickness can vary along the entire length of the thread 32, or at least along a portion of its length. Figure 5 It is shown that the thread thickness can be greater in the central region 30, and thinner in the apical region 26 and the coronal region 28. It is believed that this variable thickness design, where the thread thickness of the central region 30 is greater than the apical region 26 and the coronal region 28, can provide certain advantages as described below.

[0044] Furthermore, the center point of each crest 34 can be used to determine the thread pitch. In Figure 5 The thread pitch of the thread 32 can be observed from the center point. The thread pitch can be any suitable small angle. In certain contemplated embodiments, the thread pitch is substantially constant along the length of the body. However, in the illustrated example, the thread pitch is variable. As can be observed from Figure 5 It can be observed from

[0045] As the thread 32 spirals along the body, the flanks between turns of the thread 32 remain substantially parallel to the central axis A. The axial length of the flanks between turns of the thread 32 is substantially equal along the length of the body. At any location along the thread 32, the axial length of the flanks will be substantially the same. Notably, even though the thread thickness 38 varies, in the illustrated example, the axial length of the flanks remains substantially constant.

[0046] The non-uniform offset 36 (trailing flank side vs. leading flank side), the varying thread thickness, the slight variation in thread pitch, combined with the substantially constant axial length of the flanks, work together to alternately compress and expand cellular structures when the implant is implanted into a living host material such as bone. For bone and other living tissue, this cyclical compression and expansion action activates the natural healing response, promoting tissue regeneration and ingrowth. In turn, these processes quickly provide long-term stability for the implant 20.

[0047] The central region 30 of the implant 20 is provided with a set of flutes 40. The number of flutes 40 can be any reasonable number. Figure 6 The end view shows one embodiment in which the implant 20 is provided with 8 flutes 40. Regardless of the number of flutes, it is preferred that the flutes 40 are equally spaced from one another in the circumferential direction. In the example in which the implant 20 contains 8 flutes (e.g. Figure 6), each flute 40 will be circumferentially offset by 45° from the next adjacent flute. Each flute 40 extends longitudinally along the length of the central region 30, as best seen in Figure 2 . That is, the flutes 40 are primarily confined to the central region 30; in the example shown in the drawings, the flutes 40 do not extend significantly into the apical region 26 or the coronal region 28, except for a small amount of extension. In other contemplated embodiments (not shown), the flutes can extend substantially through and / or completely through one or both of the apical region 26, the coronal region 28.

[0048] It can be seen that the flutes 40 are not continuous, uninterrupted grooves. Rather, each flute 40 is composed of a plurality of individual, discrete flute segments, which are separated from one another by the gaps between the turns of the thread 32. Each discrete flute segment is formed as a scalloped notch on the crest 34 of the thread 32. That is, each flute 40 is actually arranged from a number of individual segments, which can be likened to a walkway composed of a series of individual and spaced apart stepping stones. The spaces or gaps between each turn of the thread 32 will intersect the flutes 40 at each revolution, thereby dividing each flute 40 into a series of segments, as best seen in the end view of Figure 6 . Thus, a plurality of flute segments collectively make up a flute 40. For ease of understanding, assume that each flute 40 is composed of an average of 7 flute segments, and that the implant 20 is provided with 8 flutes 40, then the total number of flute segments is approximately 56, which are evenly distributed on the exterior of the central region 30 of the implant 20. The flutes 40 are beneficial in that they increase the surface texture to provide more bone contact with the implant 20, thereby enhancing stability.

[0049] Each discrete flute segment within the same flute 40 is circumferentially offset from the next adjacent discrete flute segment, thereby creating a helical twist. This helical twist is best seen in Figure 2 and Figure 6 . (In the alternative embodiment of Figure 14 , the helical flutes 40' are likewise apparent.) In one example, the circumferential offset angle of each flute segment from the next adjacent discrete flute segment can be -10°. In this case, the helical twist angle of each flute 40 is -10°. A negative value for the helical twist (e.g., -10°) indicates a left-handed twist. That is, the flutes 40 run or propagate in the opposite direction from the direction of rotation required to screw the implant 20 into the prepared hole. Of course, a twist of -10° is merely an example, and other twist angles are within the spirit and scope of the present invention.

[0050] In the illustrated example, each flute 40 has a generally constant flute depth and a generally uniform flute width / span. That is, each flute segment is generally the same size and shape. But this is not a hard and fast requirement. In some contemplated embodiments, the flutes 40 can be designed to have varying depths and / or widths, and / or to have varying helical twists 62.

[0051] One advantage of the left-hand twist of the flutes 40 is realized in the context of implant 20 removal. Most host materials, especially when the host material is living bone, will grow and / or expand into the flutes 40 after implant placement. This migration can be due to elastic and semi-elastic material recovery (springback) due to stresses induced in the host material, and for living host materials such as bone and live wood, can also be the result of ingrowth. Host material that enters the flutes 40 will mechanically lock the implant 20 in place. Any attempt to unscrew the implant 20 will be impeded by the host material that is trapped in the flutes 40, which will act as a mechanical impediment due to the left-hand twist.

[0052] In the illustrated example, each flute 40 has a generally constant flute depth and a generally uniform flute width / span. That is, each flute segment is generally the same size and shape. But this is not a hard and fast requirement. In some contemplated embodiments, the flutes 40 can be designed to have varying depths and / or widths, and / or to have varying helical twists 62.

[0053] The central region 30 also includes a set of compression ramps 42 that are disposed along the crests 34 of the thread 32 between the flute segments. That is, the compression ramps 42 are located on the crests 34 between adjacent flutes 40 in the central region 30. Each compression ramp 42 has a low leading edge and a high trailing edge that are arranged in a right-hand direction. That is, the adjectives “leading” and “trailing” are based on the right-hand direction of implant 20 screwing into a prepared hole. During rotation, the low leading edge will move ahead of the high trailing edge, like a ramp or wedge. Further details regarding the compression ramps 42 can be found in PCT Patent Application WO2020086611A1, the entire disclosure of which is hereby incorporated by reference and relied upon in jurisdictions that recognize incorporation by reference.

[0054] Each compression ramp 42 is configured to impart a localized compressive strain to the inner surface of the host material by densification during the threading of the implant 20 into the prepared hole. More specifically, the helical band of host material that rubs against the thread crests 34 is directly affected by the compression ramps 42. The regions of host material that do not rub against the thread crests 34, i.e., the regions distributed along the gaps between the threads 32, are not directly affected by the compression ramps 42. As the compression ramps 42 pass over (drag) a portion of the inner surface of the hole, localized regions of highly stimulated and highly compressed bone (or other host) material are created, which can be referred to as superactivation zones. The compression ramps 42 also create stresses in the surrounding host material by their own scraping action. It is understood that the implantation of the implant 20 will result in a helical band of host material being superactivated by the compression ramps 42, while the helical bands of host material in between are subjected to significantly less stress. It is envisioned that the superactivated helical band of host material will be distributed along the embedded threads 32, while the helical bands of host material subjected to less stress will fill the cavities between the threads 32. Thus, during the threading of the implant 20 into place, a double helix of superactivated and less stressed host material is created within the walls of the hole.

[0055] Almost instantaneously, the living host material begins to fill the voids of the flute 40. The induced stresses, within the elastic deformation capabilities of the host material, convert themselves into a counter force and quickly return to the undeformed state upon stress relief. Thus, the counter force causes the surrounding bone or host material to rebound into the voids of the flute 40. The effect will be that the host material shrinks around the implant 20 and rushes into the flute 40.

[0056] The scalloped notches in the thread crests 34 of the threads 32 provide room for the bone to rebound to its original shape. This phenomenon allows the flute 40 to be understood as a healing cavity. That is, the healing cavities will effectively attract bone (or other host material). The healing cavities, as incubation sites, quickly achieve secondary stability. The healing cavities promote and encourage bone growth to fill the voids.

[0057] For living host materials such as bone, when the induced stresses exceed the elastic deformation capabilities of the bone, the bone undergoes a permanent change in shape through plastic deformation. In bone, this permanent change in shape can be accompanied by the creation of microcracks that release energy, a natural defense against complete fracture. It is believed that the microcracks create blood flow, which in turn causes the formation of blood clots in the voids of the flute 40. All of these stimuli activate the natural healing capabilities of the bone, which rapidly grow new bone into the flute 40. Thus, the superactivation zones promote the natural healing capabilities of the body, which accelerates recovery and improves bone integration, especially in the healing cavities created at each flute segment after the implant 20 is fully seated.

[0058] Over time, a solid, dense layer of new bone growth forms around the implant 20 under the combined action of the super-activation zone and the counterforce. The healing cavities fill with solid new bone, locking the implant 20 in place. As previously estimated, the illustrated implant 20 can contain a total of about 56 flute segments. This means that 56 discrete healing cavities are distributed evenly across the entire outer central region 30, which can foster new bone growth and accelerate the osseointegration process. This extensive and even distribution of discrete healing cavities can greatly accelerate the healing process while mechanically locking the implant 20 in place almost instantaneously.

[0059] When the implant 20 is screwed into place, the host material trapped in the gaps between the turns of the thread 32 is subjected to significantly less disturbance. The axial length of the thread root is substantially constant, meaning that the portions of host material between the turns of the thread 32 are not subjected to the same degree of direct disruption during installation of the implant 20. In contrast, the spiral band of host material in contact with the thread crest 34 of the thread 32 is subjected to intense stimulation and disturbance as the implant 20 is screwed into place due to the action of the compression ramp 42. This intensely stimulated and disturbed band of host material does not directly affect the host material trapped in the gaps between the turns of the thread 32. Thus, the host material trapped in the gaps between the turns of the thread 32 retains a high degree of its natural structural integrity.

[0060] The host material trapped in the gaps between the turns of the thread 32 can be referred to as a controlled compression zone. The controlled compression zone refers to the spiral band of host material from the apical end 22 to the coronal end 24 and between the body of the implant 20 (i.e., the thread root) and the thread crest 34 of the thread 32. The controlled compression zone can be designed to regulate the effect on the host material. Again referring to Figure 4 In the apical region 26, the controlled compression zone gently and progressively moves the host material at the thread root and crest 34 of the thread 32. This is reflected in the difference between the minor and major diameters of the thread 32, i.e., the rate of change of the offset 36 along the length of the implant 20. When the rate of change of the offset 36 decreases (i.e., the offset 36 changes more gradually), the relative displacement of the host material in the spiral band affected by the thread crest 34 of the thread 32 also decreases. In relative terms, in the apical region 26 of the controlled compression zone, although the thread root and crest 34 of the thread 32 both push the host material outward, the pushing action of the crest 34 is attenuated. Figure 4 As the relative length of the dashed centerline vector decreases, the relative displacement of the host material in the spiral band affected by the thread crest 34 of the thread 32 also decreases. In relative terms, in the apical region 26 of the controlled compression zone, although the thread root and crest 34 of the thread 32 both push the host material outward, the pushing action of the crest 34 is attenuated.

[0061] In general, the twist direction of the compression ramp 42 is consistent with the flute. Thus, when the flute 40 is left-handed, the compression ramp 42 is also left-handed. The left-handed twist of the compression ramp 42 imparts an angle to each of the compression ramps 42 that naturally exerts an axial outward stress on the wall of the hole and any host material (e.g., bone particles mixed with a liquid) that is present. "Axial outward" refers to a component of the stress in a direction away from the bottom of the prepared hole and toward the opening of the hole, i.e., in the upward direction as viewed in Figure 1 , Figure 9 and Figure 10 .

[0062] In the central region 30 of the controlled compression zone, the thread 32 imparts a substantially equal outward displacement of the host material from both the root 32 and the crest 34, as evidenced by the relatively equal central taper R2 and crest taper C in Figure 3 . Thus, the apical region 26 induces a non-equal relative displacement of the controlled compression zone and the super-activation zone affected by the crest 34, while in the central region 30, the continued displacement of the host material is relatively equal. Upon re-entering the coronal region 28 of the controlled compression zone, a non-equal relative displacement of the super-activation zone is experienced. One purpose of this design is to modulate the radial stress in the host material in a manner similar to a massage. For example, in human bone, the outer layer is typically hard cortical bone, while the inner portion is soft cancellous bone. See Figure 1 . By modulating the radial stress in the hard cortical bone region, stress fractures are less likely to occur around the implanted implant 20.

[0063] This modulation can produce certain beneficial pre-treatment effects, i.e., a preliminary and gentle compression of the bone particles that are displaced by the root of the implant or the crest 34 of the thread 32. It should be noted that the bone particles affected by the pre-treatment effects of the implant 20 can be autograft live bone particles, original live bone particles, or a mixture of both. In either case, the pre-treatment effects activate and enhance the activity of the live bone and bone particles. The modulated stress applied to the bone particles causes a certain degree of displacement of the bone particles and a re-arrangement of the micro-fractures that were created during the initial hole formation. Thus, a substantial portion of the sidewall of the osteotomy hole is cold worked back and forth, which promotes rapid healing of the affected bone particles and bone integration with the implant 20.

[0064] When the implant 20 is first implanted, the host material trapped in the gaps between the turns of the threads 32 (the so-called controlled compression zones) can provide a high level of initial stability, or primary stability, for the implant 20. In the hours and days after the implant 20 is implanted, the healing cavity has not had enough time to fill with new bone and achieve bone integration. It is at this stage that the host material in the gaps between the turns of the threads 32 initially fixes the implant 20 in place. After the hyperactivated zones and the healing cavity have had enough time to promote new bone growth, the new bone growth provides significantly enhanced secondary stability for the implant 20, allowing the implant to withstand full load under all normal circumstances.

[0065] The root tip 22 is defined by at least one, but preferably a pair of, cutting edges 44. In practice, the cutting edges 44 are edges disposed on opposite sides of the root tip 22. Where a pair of cutting edges 44 is provided, these edges may or may not lie in the same plane passing through the central axis A. Figure 6 In the illustrated embodiment, it can be seen that the cutting edges 44 do not lie in the same plane. Instead, in this example, the cutting edges 44 are slightly offset laterally (with respect to direct diametrical alignment) over a relatively short span on opposite sides of the central axis A. To maintain balance and symmetry, it is advantageous for the pair of cutting edges 44 to be arranged diametrically opposite each other, even if they are not in the same plane.

[0066] The edge of each cutting edge 44 mentioned above extends generally in the radial direction. Figure 6 For example, each edge is offset relative to the central axis A, but it can be understood that although these edges are not completely distributed along the radial line extending from the central axis A, they still mainly or mostly extend in the radial direction. Even if the extension direction of the edge is slightly radial, the expected success can be achieved. Each edge is formed between the plowing surface 46 and the support surface 48. Depending on the manufacturing process adopted and the designer's choice, the plowing surface 46 can be a curved surface or a flat surface. In the example shown, the plowing surface 46 is roughly flat, and the plane in which it is located is roughly parallel to the central axis A. The support surface 48 can also be a curved surface or a flat surface. In the example shown, the support surface 48 is roughly flat.

[0067] exist Figures 6-8As can be seen, each cutting edge 44 has a micro-chamfer 50 that is generally planar; it should be understood that the micro-chamfer 50 is an optional feature. That is, the micro-chamfer 50 can be added proximate the edge of the support surface 48, but the implant 20 will function properly even without the micro-chamfer 50. The micro-chamfer 50 constitutes a secondary chamfer relative to the primary chamfer formed by the support surface 48. The micro-chamfer 50 can improve the cutting performance of the cutting edge 44 by forming a micro-chamfer angle with the respective cutting edge 44. The micro-chamfer angle can vary between about 25° and 60° to optimize performance and durability in the application. In practice, the micro-chamfer angle can be about 45° when measured in a plane that is perpendicular to the central axis A. In the illustrated example where the plow surface 46 is parallel to the central axis A, the same measurement is obtained if the angle between the intersecting plow surface 46 and the micro-chamfer 50 is measured directly. It will be appreciated that the two opposing micro-chamfers 50 are oriented in opposite directions so that the micro-chamfer 50 follows the respective cutting edge 44 as the implant 20 is screwed into place. In this configuration, the implant 20 naturally rotates in the cutting direction, at which time the cutting edge 44 cuts or gouges the bone at the bottom of the osteotomy hole. Or stated differently, the cutting direction can be defined as the direction in which the cutting edge 44 rotates and sweeps through and into the bone (or other host material in non-medical applications).

[0068] Each support surface 48 is formed proximate each micro-chamfer 50 and forms a primary angle outwardly therefrom. The primary angle is less than the micro-chamfer angle. In the illustrated example where the micro-chamfer 50 is 45° relative to the axis A, the support surface 48 can be 40° or less. In general, the difference between the micro-chamfer angle and the primary angle is only a few degrees, typically less than 10°.

[0069] In the illustrated example, the lead-in ramp 52 is located at the bottom of the plow surface 46. The lead-in ramp 52 extends between the support surface 48 and the plow surface 46. In the illustrated example, the lead-in ramp 52 is formed proximate each support surface 48 and forms a third angle outwardly therefrom. The third angle is less than the primary angle. In the example where the leading support surface 48 is 40° relative to the axis A, the lead-in ramp 52 (i.e., the third angle) can be 30° or less. Each lead-in ramp 52 is disposed within one of the scalloped regions of the root tip 22 between the support surface 48 and the cutting edge 44.

[0070] The lead-in ramp 52 has at least two functions. One of the functions is to form at least one thread point, and preferably a plurality of thread points, on the plow surface 46. This function is accomplished by the lead-in ramp 52 dividing one or more turns of the thread 32, as shown in Figure 7 and Figure 8This creates one or more sharp teeth in the apical region 26 that cut clearance for the threads 32 as the implant is advanced in the host material with a screwing action. Another function of the feed ramp 52 will be discussed below in conjunction with Figure 10 and Figure 12 Provide explanation.

[0071] Some expected implant 20 embodiments can omit the feed ramp 52, and only need to design and extend the support surface 48 to connect with the opposite plowing surface 46. In this case, the support surface 48 will assume the function of the feed ramp 52.

[0072] exist Figures 1-8 In the illustrated embodiment, the apical tip 22 of the implant 20 is provided with a valley 54. In these examples, the valley 54 is represented by a short offset space between the cutting edges 44. In other words, the apical tip 22 of this embodiment is provided with a groove-like space or indentation. As shown, the valley 54 extends transversely to the central axis A and generally perpendicular to the plowing surface 46. In other words, the valley 54 extends generally perpendicular to the cutting edges 44, separating them from one another.

[0073] from Figure 2 and Figure 3 As can be seen from the side view of , the valley 54 can have a generally flat bottom and generally axial sidewalls. However, the valley 54 can also adopt other shapes, including U-shaped cross grooves, V-shaped cross grooves and other structural forms.

[0074] Figure 9 The implant 20 is shown partially inserted into the prepared hole. As the implant 20 is screwed downward into the prepared hole, the outermost edges of the cutting edges 44 scrape and cut the host material, the self-tapping teeth cut grooves for the threads 32, and the valleys 54 have little interaction with the host material. As the apex 22 descends toward the bottom of the hole, particles of host material (e.g., bone) generated by the cutting edges 44 and the self-tapping teeth accumulate around the apex 22.

[0075] Figure 10 The implant 20 is shown after reaching its final depth within the prepared hole. In most cases, the original bottom of the hole will be slightly shallower than the total length of the implant 20. In this case, i.e., when the length of the implant 20 is greater than the depth of the prepared hole, the cutting edge 44 will begin to scrape and cut the bottom of the hole just before reaching the full depth, cutting bone and generating a certain amount of bone debris 56. The bone fragments 56 cut and lifted by the cutting edge 44 will accumulate in the feed ramp 52 and accumulate on the plowing surface 46. These detached bone fragments 56 act as seeds for bone growth promoters, promoting new bone ingrowth and osseointegration.

[0076] The bone densification methods described in U.S. Patent 9,326,778 and U.S. Patent Application Publication 20190029695A1 have as one of their well-documented products a layer of bone slurry formed along the sidewalls and at the bottom of the osteotomy hole. In fact, the amount of bone slurry at the bottom of the osteotomy hole is typically the most. This bone slurry is very beneficial to the healing process. This bone slurry resulting from the bone densification process significantly enhances and promotes bone ingrowth, bone regeneration, and bone integration. Thus, as shown in Figure 10 the apical end 22 of the implant 20 enters this pool of bone slurry, the bone slurry is extruded and begins to migrate upward (i.e., toward the coronal end 24).

[0077] As previously mentioned, the compression ramp 42 will cause a scraping or shaving effect on the interior surface of the prepared hole. When the implant 20 is screwed into place, the angle of the compression ramp 42 will naturally exert an axial stress on the hole walls and the bone granular slurry, somewhat akin to the impeller of a turbopump. Under the influence of this exerted stress, the bone slurry migrates - under the combined effect of the volume contraction embodied by the offset 36 at the compression ramp 42 and the apical region 26, the bone slurry is pumped, as it were, toward the open end of the hole. As the migrating bone slurry is lifted into the central region 30, it is apparent from Figure 5 that the volume increase embodied by the enlarged offset 36 in the central region 30 will help to more quickly draw the bone slurry to the open end of the hole. That is, comparing the rate of change of the offset 36 in the apical region 26 and the central region 30, it is apparent that all of the fluid materials in these spaces will be subjected to positive and negative pressures as the implant 20 is screwed into place. In the central region 30, a sort of relative vacuum will lift and pull the bone granules and bone slurry up from the bottom of the prepared hole. By actively distributing the bone slurry throughout the length of the implant 20, the aforementioned beneficial healing effects can be maximized. Thus, the bone slurry is drawn into the healing cavity distributed around the implant 20, forming new bone growth at multiple discrete sites.

[0078] To prevent the bone slurry from being drawn out of the hole too much, the coronal taper R3 is preferably greater than the central taper R2. In this way, the coronal taper R3 can perform a cork function. That is, the bone slurry that is moved toward the open end of the hole due to the structural design of the offset 36 in the apical region 26 and the central region 30 will be blocked, or at least delayed, by the relatively larger coronal taper R3. Ideally, little to no bone slurry will leak out of the prepared hole before the implant 20 is fully seated. In this way, the novel shape design of the implant 20 takes full advantage of the healing capabilities of the bone slurry, thereby shortening the healing time and improving the final stability of the implant 20.

[0079] In Figures 1-11In the enlarged view, it can be seen that as the implant 20 reaches the final depth within the osteotomy hole, a quantity of bone debris 56 accumulates on the plow face 46 and within the central chamber formed between the valley 54 of the implant 20 and the bottom of the osteotomy hole preparation. These bone fragments 56, which have collected in the feed ramp 52 and the valley 54, act as bone growth stimulants to promote new bone ingrowth and osseointegration. However, due to the presence of the valley 54, a central portion of the bottom of the osteotomy hole remains relatively undisturbed by the implant 20. This undisturbed area forms a generally circular bone pillar 58 due to the rotation of the cutting edge 44. The bone pillar 58 is a feature of the implant 20 that enhances stability. The bone pillar 58 acts as a self-locking point or dowel of bone, embedded within the valley 54, to further resist lateral displacement under load. Additionally, the valley 54 significantly increases the surface area of the apical end 22, thereby increasing the bone-to-implant contact, which in turn enhances stability.

[0080] The apical end 22 can be designed in various forms other than the one shown with the valley 54. In some contemplated embodiments, the apical end 22 can take on a simple blunt or rounded shape. Figures 12-15 ​ Another alternative embodiment of the implant 20' is shown, wherein the aforementioned valley 54 is eliminated in favor of a chisel-shaped tip 60'. As in the previous example, the cutting edge 44' here is the edge that is angled upward and outward (generally radially) from the apical end 22'. Each cutting edge 44' is formed between the plow face 46' and the support face 48'. A micro-chamfer 50' can be added to the support face 48' near the cutting edge 44'. A feed ramp 52' is located at the bottom of the plow face 46' and extends to the adjacent support face 48'.

[0081] As in the previous example, as the implant 20' is screwed into the prepared hole, the outermost edge of the cutting edge 44' will shave and cut the host material, and the self-tapping teeth will cut the grooves for the threads 32'. The host material particles (e.g., bone debris 56') released by the cutting edge 44' and the self-tapping teeth will accumulate around the apical end 22' as they descend toward the bottom of the hole. The bone debris 56' will collect in the feed ramp 52' and pile up on the plow face 46'. These shed bone fragments 56' act as seeds for bone growth stimulants to promote new bone ingrowth and osseointegration with the implant. Although there can not be a feature corresponding to the bone pillar 58 of the previous embodiment in this case, the multi-faceted shape of the apical end 22' still significantly increases the bone-to-implant contact area, resulting in great stability.

[0082] The foregoing invention has been described in accordance with the relevant legal standards, thus the description is exemplary in nature and is not intended to limit the scope of the invention. Variations and modifications as will be obvious to those skilled in the art are intended to be within the scope of the invention.​

Claims

1. An implant for screwing into a prepared hole, characterized in that The implant comprises: a body extending longitudinally along a central axis between an apical end and a coronal end, the body having an apical region extending from the apical end, the body having a coronal region extending from the coronal end and a central region between the apical region and the coronal region; at least one thread protruding from the body and helically wound along the body from the apical region to the coronal region in successive turns, the thread having crests, the body having roots between adjacent turns of the thread; the central region including a set of flutes, each of the flutes extending longitudinally along the central region, each of the flutes being comprised of a plurality of individual and discrete flute segments, the discrete flute segments being formed in the crests of the thread; the central region including a set of compression ramps, each of the compression ramps being disposed between two circumferentially adjacent flute segments along the crests of the thread, each of the compression ramps having a low leading edge and a high trailing edge in a right hand direction; the apical end having at least one cutting edge, the cutting edge having a generally radially extending edge formed between a plow face and a support face.

2. The implant of claim 1, wherein, further comprising a valley disposed at the apical end, the valley traversing the central axis.

3. The implant of claim 2, wherein, the valley extends generally perpendicular to the plow face.

4. The implant of claim 2, wherein the valley has a generally flat floor.

5. The implant of claim 2, wherein the first and second portions are substantially cylindrical. the valley has a generally axially extending sidewall.

6. The implant of claim 2, wherein the at least one cutting edge includes a pair of cutting edges disposed diametrically opposite one another, the valley separating the cutting edges.

7. The implant of claim 1, wherein the plow face is generally planar and the support face is generally planar.

8. The implant of claim 7, wherein the first and second portions are substantially parallel to each other. the plow face is disposed in a plane generally parallel to the central axis.

9. The implant of claim 1, wherein, further comprising a micro-chamfer disposed at the support face proximate the cutting edge.

10. The implant of claim 1, wherein, further comprising a lead-in ramp at the bottom of the plow face, the lead-in ramp dividing at least one turn of the thread to form a self-tapping tooth on the plow face.

11. The implant of claim 10, wherein the first and second portions are substantially cylindrical. the lead-in ramp extends between a support face and a plow face.

12. The implant of claim 1 wherein, the thread has a thread thickness measured axially at the crest, the thread thickness being variable along the thread.

13. The implant of claim 12, wherein the first and second portions are substantially cylindrical. the thread thickness of the central region is greater than the thread thickness of the apical region and the coronal region.

14. The implant according to claim 1, wherein the crest of the thread is truncated, the thread having an offset measured radially from the root to the crest.

15. The implant of claim 14, wherein the first and second portions are substantially cylindrical. the thread has an anterior flank toward the apical region and a posterior flank toward the coronal region, the offset on the posterior flank of the thread being unequal to the offset on the anterior flank of the thread.

16. An implant for screwing into a prepared hole in a living bone, characterized in that The implant comprises: a body extending longitudinally along a central axis between an apical end and a coronal end, the body having an apical region extending from the apical end, the body having a coronal region extending from the coronal end and a central region between the apical region and the coronal region; at least one thread protruding from the body and spirally winding along the body from the apical region to the coronal region in a continuous winding manner, the thread having a crest, the thread having an anterior side facing the apical region and a posterior side facing the coronal region, a portion of the body located between adjacent turns of the thread constituting a root bottom, the root bottom spiraling along the body; The body has an apical taper throughout the apical region, the apical taper being between about 2° and 30° relative to the central axis; the body has a coronal taper throughout the coronal region, the coronal taper being between about 5° and 35° relative to the central axis; and the body has a central taper throughout the central region, the central taper being between about -5° and +15° relative to the central axis; The central region includes a plurality of chip flutes, each of the chip flutes extending longitudinally along the central region, and each of the chip flutes is composed of a plurality of independent and discrete chip flute segments, the discrete chip flute segments being formed on the crests of the threads, the discrete chip flute segments within each chip flute being circumferentially offset from the next adjacent discrete chip flute segments to form a helical twist, the helical twist being in a left-handed direction; The central region includes a set of compression bevels, each of which is disposed between two circumferentially adjacent flute segments along the crest of the thread, each of which has a low leading edge and a high trailing edge in a right-handed direction; and The root tip has a pair of cutting edges, each of the cutting edges having an edge extending substantially in the radial direction and formed between the plowing surface and the support surface, the pair of cutting edges being radially opposed to each other.

17. The implant of claim 16, wherein the first and second portions are substantially cylindrical. The invention also includes a valley disposed at the root tip, the valley separating the cutting edges and crossing the central axis, the valley extending substantially perpendicular to the plowing face.

18. The implant of claim 16, wherein, The thread has a thread thickness measured in the axial direction at the crest, the thread thickness being variable along the thread, and the thread thickness in the central region being greater than the thread thickness in the apical region and the coronal region.

19. The implant of claim 16, wherein The crest of the thread is truncated, the thread has an offset measured radially from the root to the crest, the offset on the rear flank of the thread being unequal to the offset on the front flank of the thread.

20. An implant for screwing into a prepared hole in a living bone, characterized in that The implant comprises: a body extending longitudinally along a central axis between an apical end and a coronal end, the body having an apical region extending from the apical end, the body having an apical taper throughout the apical region; the body having a coronal region extending from the coronal end, the body having a coronal taper throughout the coronal region; and a central region located between the apical region and the coronal region, the body having a central taper throughout the central region; at least one thread protruding from the body and helically winding along the body from the apical region to the coronal region in a continuous winding, the thread having a pitch that is variable along the length of the body; the thread having an anterior flank facing the apical region and a posterior flank facing the coronal region; the portions of the body between adjacent windings of the thread forming a root, the root having a substantially planar surface that spirally coils along the body and is substantially parallel to the central axis; the thread having a truncated crest, the thread having an offset measured radially from the root to the crest, the offset on the posterior flank of the thread being unequal to the offset on the anterior flank of the thread; the thread having a thread thickness measured axially at the crest, the thread thickness being variable along the thread, and the thread thickness of the central region being greater than the thread thickness of the apical region and the coronal region; the central region including a set of flutes, each of the flutes extending longitudinally along the central region, and each of the flutes being comprised of a plurality of independent and discrete flute segments, the discrete flute segments being formed at the crest of the thread, the discrete flute segments within each of the flutes being circumferentially offset from the next adjacent discrete flute segment to form a helical twist, the helical twist being in a left-hand direction; the central region including a set of compression ramps, each of the compression ramps being disposed between two circumferentially adjacent flute segments at the crest of the thread, each of the compression ramps having a low leading edge and a high trailing edge in a right-hand direction; the apical end having a pair of cutting edges that are diametrically opposed to each other, each of the cutting edges having a substantially radially extending edge formed between a plow face and a support face, the plow face being substantially parallel to the central axis, the support face having a micro-chamfer proximate to the edge; a valley disposed at the apical end, the valley being transverse to the central axis, the valley extending substantially perpendicular to the plow face, the valley separating the cutting edges.

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