Self-aligning multi-unit abutment system for dental prostheses

Abstract

A multi-unit abutment aligning a dental implant and a screw-attached prosthesis with copings is disclosed. The multi-unit abutment has a threaded base post for attachment to the implant and a ball portion. A one-piece swivel shell surrounds the ball and may be fixed in position without a lock screw. A drive feature on the ball allows a tool passing through the lock screw to drive the base post into the implant with the multi-unit assembly in a linear configuration. The swivel shell is then positioned and fixed at a desired tilt and azimuthal angle. The swivel shell has a mating surface for a coping. The multi-unit abutment can be used for full arch dental prosthesis. The multi-unit abutment can provide passive changes in alignment of the swivel shell relative to the ball in response to native forces or changes, over time.

Description

SELF-ALIGNING MULTI-UNIT ABUTMENT SYSTEM FOR DENTAL PROSTHESESREFERENCE TO RELATED APPLICATIONS

[0001] This disclosure claims priority to U.S. Provisional Patent Application Serial Number 63 / 509.529, filed on June 22, 2023, which is incorporated herein by reference in its entirety.FIELD OF THE INVENTION

[0002] The present invention relates to dental implant systems.BACKGROUND

[0003] Different systems have been introduced for attaching dental prostheses to dental implants to replace one or more natural teeth. In order to simplify future modification or replacement needs, it is desirable to have reversable attachment between the implants and prostheses using mechanical systems as opposed to directly bonding these components together. These systems may include features to provide both proper alignment and retention for acceptable use by the patient. Intermediate components such as Ti bases (also called copings) and separable abutments are often employed to provide proper registration between a dental prosthesis, one or more implants embedded in the patient’s jawbone, and the soft- tissue and any remaining natural teeth. These intermediate elements may be mutually attached with screws, ball-and-socket joints, snap-on mounts, cement or other mechanical means.

[0004] The simplicity of screw-attached systems provides some benefits over snap-on systems beyond fabrication cost. The mounting pressure between the coping and abutment is readily controlled through the torque applied to the screw to tighten it. This axial tension control and the self-aligning characteristics of engaged screw threads provides more certainty in the engagement force and relative orientation of the components. Even if a screw breaks, techniques are known for removing the pieces without damage to surrounding components. Screws also have a benefit of independence for removal since each coping can be loosened individually. Tilting the prosthesis after screw removal to disengage one coping cannot cause reengagement of another coping. Potential damage to the prosthesis or the implant from the stresses of attaching and removing snap-on systems are also avoided. Unlike screw-attached systems, snap on systems do not require access holes to engage prosthetic screw heads and may accommodate some misalignment in parts through variable compression forces. As aresult, both ty pes of systems are expected to be used for the foreseeable future. Both systems benefit from having the best alignment between interfacing components.

[0005] In the case of a single-tooth crown attachment, the Ti base and abutment surfaces preferably include features to remove rotational symmetry about the azimuthal axis in the mating of the abutment and coping surfaces. Rotational locking features may also be included in these single mount systems. When the prosthesis contains multiple copings for attachment to multiple abutments as in the current disclosure, this rotational fixation is not generally required. For example, 30-degree tapered mating surfaces for multiple interface locations are sufficient to provide complete registration. This form is illustrated in the drawings of this disclosure for convenience but is not meant to be limiting. While such symmetry simplifies modelling of mechanical stresses, many inventive concepts disclosed in the present document can be applied to axially asymmetric systems. These are considered to be part of the scope of the inventive concepts herein.

[0006] The goal for all implant attached prostheses is to have a passive fit of the prosthesis superstructure to the implants to avoid stress on the prosthesis or on the osseointegration process of the implants. These stresses may cause problems during the initial loading or crop up much later. Misfit can lead to both mechanical and biological problems in single implant and multiple implant treatments. The mechanical problems may include loosening of prosthesis retaining and abutment screws and fracture of components including screws. Biological issues may include discomfort, progressive marginal bone loss, bacterial infection, microbial plaque buildup and implant loosening.

[0007] Having a passive fit initially or being able to readjust or rework components later to adapt to changes are important for successful prosthesis functionality and survival. Due to the build-up of tolerances and introduction of misalignments and distortions in producing a prosthesis, attaining a passive fit remains a challenge. The use of direct pick-up impression procedures is beneficial, but improvements are still needed. A review of passive fit challenges has been provided by Buzayan, M. M., & Yunus, N. B. (2014) / ‘Passive Fit in Screw Retained Multi-unit Implant Prosthesis Understanding and Achieving: A Review of the Literature” Journal of Indian Prosthodontic Society, 14(1), 16-23 and Katsoulis et al. (2017) '‘Misfit of implant prostheses and its impact on clinical outcomes. Definition, assessment and a systematic review of the literature,” European Journal of Oral Implantology , 10 (Suppll), 121-138. The amount of allowable misfit for successful outcomes is still uncertain, but gap limits of 10 to 150 microns have been proposed for mechanical tolerances. In order to exclude periodontally harmful bacteria, gaps would need to be lessthan 2 microns. Although quantitative measures of passive fit are lacking, there is agreement that clinicians should strive to achieve the least degree of misfit possible.

[0008] A treatment option for edentulous patients that is gaining popularity involves the placement of four to eight implants in the edentulous jaw and the mounting of a prothesis arch. A transmucosal abutment is fastened to the implant and intended to remain in place indefinitely. While it would be desirable to have the axes of all of the implants located parallel to one another, underlying bone structure often results in installing implants at an angle from this ideal mutual orientation. ‘’Multi-unit abutment” is a popular descriptor for a specific type of transmucosal abutment used for the restoration of the edentulous jaw with a single prosthesis, that is a full arch prosthesis.

[0009] The multi-unit abutment (commonly referred to as an “MU A”) is a fairly easy way to improve divergent angulations of implants with options of 0 degree, 17 degrees, and 30 degrees angulation corrections. Generally, 0 degree MU As are easier to position because the abutment is positioned in line with the linear axis of the implant. The 17 and 30 degree MU As typically include a “screw access” indicator that is relatively long and difficult to work around in tight spaces, such as the posterior of the jaw where these abutments are commonly positioned to compensate for the disto-angulation of the posterior implants popularized by Dr Paolo Maolo in 2004.

[0010] There have been several alternative abutment designs for the restoration of the edentulous arch. Although most implant companies have settled on the MUA geometry adopted by Nobel Biocare, there have been some attempts to improve on the weaknesses of that geometry. For example, Dentsply Implants Astra EV system uses a “mulTi base” abutment that improves on the lack of coverage of the prosthetic screw in the multi-unit abutment. Neoss uses a version of the MUA that “reduces the height of the abutment” by using a female connection as opposed to the standard male connection of the MUA. Regardless of the benefits of these improved designs, each design requires the clinician to order a specific stock of specific angulation corrections and heights. An example of the complexity of the inventory management is when the implant system offers multiple implant / abutment connections (e.g., narrow platform and regular platform) and multiple heights to the MU As (e.g., 1.5 mm, 2.5 mm, 3.5 mm, 4.5 mm, etc.) as well as different angulations or tilt angles (e.g., 0 degree, 17 degrees, and 30 degrees). To maintain sufficient stock to be well-prepared for a full arch implant fixed immediate load procedure could require having the three tilt angle options multiplied by the number of platform optionsmultiplied by the number of reasonable tissue heights for the amount of implants expected to be placed (a minimum of four according to Paolo Maolo’s protocol).

[0011] The resulting inventory equation follows:3 (degree options) x 2 (platform connections) x 2 (different tissue heights) x 4 (implants) = 48 (multi-unit abutments).

[0012] This inventory problem is increased when multi-unit abutment systems also require unique implants. Ti bases and prosthetic fasteners. This inventory management complexity is further exacerbated when practitioners prefer different vendor systems under different patient circumstances, or when different practitioners in a practice prefer different vendor offerings.

[0013] In addition to the complexity of the inventory management, there is also a limitation to the discrete nature of the “angulation correction" (for example, limited to three specific angles 0, 17 and 30 degrees) and the internal connection of the implant about its longitudinal axis that may be referred to as an azimuthal angle. In many cases an internal hex limits the possibilities to 6 azimuth positions with 60 degrees of variation from one position to the next. In some cases, 0 degrees would be too little tilt angle correction, but 17 degrees is excessive. The same would hold true for 17 to 30. Or 17 degrees may be an appropriate tilt correction, but due to the limitation of the 6 positions in the internal hex, the 17 degrees of correction required cannot be applied in the ideal azimuthal direction of correction needed. The same holds true for 30-degree correction. Novice clinicians to full arch implant treatment struggle with the selection and positioning of multi -unit abutments. Procedure times are extended which can cause increased morbidity for the patient.

[0014] A 2020 paper by Omori et al. titled “Biological and mechanical complications of angulated abutments connected to fixed dental prostheses: A systematic review with metaanalysis” (Journal of Oral Rehabilitation, 47(1): 101-111) finds a statistically significant increase in marginal bone loss with angled abutments but does not claim this is clinically significant. Mechanical problems especially with screw loosening and other mechanical effects are found in both angulated and straight abutments. Although there is uncertainty over whether angled implants are more susceptible to loss of osseointegration than straight abutments, all implants do impart higher mechanical stress and strain on bone structures than natural teeth. Natural teeth can move an order of magnitude more in their sockets than an implant embedded in bone. This natural shock absorber helps cushion the range of force magnitudes and directions applied to the teeth from the bone. Screw loosening has been associated with bending of the screw joint and settling effects in which initial surface microroughness keeps joined parts initially separated, but high spots are gradually worndown. Microgaps from initial mechanical misfit between elements in the prosthesis superstructure may be too small for detecting with an explorer, yet large enough to concentrate mechanical forces coming from different directions at different magnitudes in the process of mastication. These microgaps may still be large compared to bacteria that can penetrate and grow in internal cavities of the overall dental prosthesis superstructure installation.

[0015] Due to the large range of variables, application specifics and difficulty of in situ measurements, there is not an accepted passive fit threshold for long-term success. The quality of fit may be tested in the dental laboratory with analogs and at installation in the patient, but this is not an exacting science. For example, a “one screw test' ’ for fit involves tightening only one screw at one end of the prosthesis and then looking for lift at the opposing end. A “screw resistance test” variant of this involves inserting and seating screws in sequence and then seeing if any needs to be turned more than 180 degrees to achieve say 10 N-cm of torque. Failure of the prescribed go-no go test criterion means that the prosthesis needs to be reworked or replaced. Since the same process will be used to fabricate the replacement, there is no certainty that this replacement will be properly aligned.

[0016] Consider the case of a screw-attached dental prosthesis that is attached with four multi-unit abutments to implants in a patient’s jaw bone. Suppose that three of them are perfectly aligned ith one another perpendicular to the plane of the jaw using 0-degree multiunit abutments, but the fourth implant is not oriented perpendicular to that plane. That is, its linear axis is not parallel to the linear axis of the other three. This is shown schematically in FIG. 1. In this figure, four Ti bases (also known as “copings”) 5 are shown incorporated into a prosthesis 68. These are shown in an idealized configuration in w hich all of the linear axes of the Ti bases are mutually parallel and the distal end seating surfaces 22 of the Ti bases are located in a single horizontal plane perpendicular to the linear axes. Three of the implants 16 in the jaw 70 have 0-degree fixed multi-unit abutments 220 for three corresponding Ti bases located in a common horizontal plane positioned in perfect registry with three of the Ti bases 5. The final implant 216 is shown with its linear axis deviating from the orientation of the remaining implants by an angle a, but in planar registry with the corresponding Ti base and with its vertical midpoint aligned with the other three implants. A 0-degree fixed multi-unit abutment 220 is installed. Suppose that the angle a is 8 degrees. In the case of the fixed angle multi-unit abutments mentioned above, the practitioner will be forced to choose betw een a fldegree and a 17-degree fixed angle abutment, both of which create a similar angular mismatch. This angular deviation is small enough to allow the prosthesis 68 to be placed withits copings 5 engaging the multi-unit abutments 220. FIG. 2 shows a cross-sectional view of the angled implant 216 and one of the remaining implants 16 with its corresponding 0-degree multi-unit abutment 220. In this figure, the prosthetic screws 6 are not completely tightened. As shown in the figure, there is an angular mismatch in the seating of the two Ti bases on the multi-unit abutments resulting from the longitudinal axes of the two implant abutments not being parallel to the axes of the Ti bases. The prosthetic screw threads are free to engage the threads of the 0-degree multi-unit abutments due to the clearance provided by the apertures 23 on the proximal ends of the Ti bases 5. In particular, the misaligned system attached to implant 216 on the left has the prosthetic screw 6 in a position where its threading is just starting to engage the threads of the implant abutment. The misalignment between the Ti base 5 and the abutment 220 is likely to improve as the prosthetic screw 6 is tightened in this example. In particular, the Ti base 5 will respond by pivoting around the contact point at seating surfaces 22 and 222. While the gaps may be reduced between Ti base 5 and implant abutment 220 on implant 216, this will come at the expense of stresses in the entire system due to misalignment. Depending upon the severity of this angular mismatch, further torquing of the prosthetic screws may result in the seating surfaces 22 of the two Ti bases 5 being pulled into aligned contact with seating surfaces 222 of the 0-degree fixed multi-unit abutments. This will depend upon the angular mismatch, material strength and flexibility of everything depicted in the figure.

[0017] In general, as the four prosthetic screws 6 are tightened, the misalignment of the fourth multi-unit abutment attached to implant 216 will naturally lead to immediate mechanical stresses in the prosthesis 68 between each of the three aligned multi-unit abutments 220 and the angled one 216 and potentially in the prosthetic screws 6 and multiunit abutments 220. Due to the rigid attachment of the Ti bases 5 to the implants, these stresses may also extend into the implants to their attachment interfaces to the jawbone 70. Note that if the angled implant 216 and its associated 0-degree implant abutment 220 were eliminated, the remaining system of three aligned and registered Ti bases and multi-unit implant abutments would be the necessary and sufficient configuration to passively align and retain the prosthesis where desired on the remaining implants. That is, the relative position of the dental prosthesis to the jaw would be constrained to be located exactly where desired at the time of installation. Even if additional elements beyond the three in this example are perfectly aligned and registered with one another from an ideal geometric perspective, the positioning may be considered to be theoretically over-constrained. Of course, as the number of implants increases in actual installations, the difficulty of ideal alignment increases and thepotential for misaligned elements to induce stress on one another increases. As the number of implants increases with their associated angular misalignments, these stresses become more complex. This angular misalignment stress from selecting from a discrete set of fixed angle abutments may be reduced by the use of omni-directional multiunit abutments that can be oriented and then fixed by torquing a locking screw at any angle within a range, for example, as described in co-owned US Patent Application 17 / 832,143 filed on June 3, 2022, which is hereby incorporated by reference as if recited in full herein.

[0018] One benefit of snap-on systems is that the compressible liner that provides the reversible retention capability can accommodate some angular misalignment between implant abutments. The snap-on systems generally include an implant abutment and a snap-on coping that includes a rigid cap and a compressible retention liner or insert. The cap typically will include exterior surface structures to improve bonding to a prosthesis and an interior structure to hold the compressible retention insert inside the cap. The compressible retention insert generally includes some mechanical profile on its interior that engages a complimentary profile on the implant abutment. The compressible retention insert or liner is compressed between the abutment and cap to provide the snap-on coupling. The geometry and material properties of the liner may be chosen to provide different degrees of retention depending upon the degree of angular misalignment between multiple abutments or how often or how easily the prothesis is expected to be removed. More recently, retention liners have become commercially available with higher retention capabilities that are designed to be as permanent as screw-attached prostheses. Like screw-attached prostheses, these systems require dental professionals and specialized tools for attachment and removal. Of course, the greater retention force can make the risk of damage from unbalanced stresses in the prosthesis greater due to the fixed positions and rigidity of the multi-unit abutments attached to the implants.

[0019] Although the retention inserts accommodate some degree of misalignment, misalignment of abutments and resulting asymmetric forces may increase stress on the implant abutment attachment to the implant, the prosthesis and or the patient’s bone containing the implants. As a result, improved passive fit of the prosthesis to the implant abutment system is desirable in these snap-on systems as well. The inventory equation with fixed angle abutments noted above still applies when angled snap-on abutments are used to reduce the potential for damage or difficulty in mounting or removing prostheses. The consumable nature of the additional assortment of relatively inexpensive retention liners adds a minor additional negative impact. .

[0020] Even if all of the multi-unit abutments are perfectly aligned and secured initially with the implants and prosthesis, changes may occur over time. For example, the prothesis may deform, or the bone structure may change, or perhaps more likely a fastener becomes loose or breaks and changes the static stress relationship between anchor points. An updated compilation of reported failures has been provided by Goodacre et al. in “Prosthetic complications with implant prostheses (2001-2017)” (European J Oral Implantology 2018; 11 Suppl LS27-S36.) In many prior art systems, the prosthesis must be completely removed to try to adjust the orientation, retighten a multi -unit abutment fastener, replace a component or perhaps even fabricate and fit a whole new prosthesis. Inefficient trial and error fitting cycles to improve alignment are frustrating to both the patient and dental practitioner. Replacing a single failed multi-unit abutment out of several and properly aligning it with an existing prosthesis may be even more difficult than the initial installation alignment. For example, a recent paper by Hess et al. titled “A technique to guide replacement of multiunit abutments supporting an existing implant-supported fixed complete denture” (J Prosthetic Dentistry, 2020 Sep;124(3):270-273) describes the difficulty in replacing one angulated multi-unit abutment of a system at the proper orientation. The process includes fabricating a specialized tool using a definitive cast with abutment analogs that attaches to an adjacent abutment. It is also reported that the impression techniques used materially affect the accuracy of definitive casts and that deformation forces and resulting distortions increase with implant angulation. For example, see Elshenawy et al., “Cast accuracy obtained from different impression techniques at different implant angulations (in vitro study)” )Intemational J of Implant Dentistry' 4, 9 (2018)) and Lee et al. “Accuracy of five implant impression technique: effect of splinting materials and methods”, (J Advanced Prosthodontics 2011;3:177-85.)

[0021] There is a general need for improved passive fit of implant supported protheses. There is a need for a way to provide adjustments to the orientation of a multi-unit abutment orientation while the prosthesis is in place not just in the repair or readjustment of complications, but also in the initial mounting to help compensate for prostheses fabrication errors. It would be advantageous to provide some self-adjustment capability without requiring intervention by a dental professional removing material to access prosthetic screw heads or trying to determine what adjustments to make to improve passive fit.

[0022] Some commercial systems require the sequential assembly of the multi-unit abutment elements in situ during their installation in the patient’s mouth. Some systems require multiple tools to be employed which can also extend procedure complexity and times.Materials and methods that eliminate chairside assembly steps or adjustments can improve clinician efficiency and patient satisfaction.

[0023] To address one or more of the above challenges and limitations of the current multiunit abutments available on the market, new multi-unit abutment embodiments are disclosed herein. These units are designated as omnidirectional and self-aligning in the sense of being able to be positioned over a continuous range of orientations sufficient for correcting implant angulation differences typically found in general practice during installation and providing re-alignment shifts due to changes over time to improve passive fit without intervention by a dental professional. Embodiments of omnidirectional multi-unit abutments are offered that have advantages in inventory management, placement procedures, options for angulation correction and flexibility, improving passive fit and to remove limitations to angle corrections or other issues with existing multi-unit abutment systems for multiple implant prostheses attachment.SUMMARY

[0024] Some embodiments of the invention include a multi-unit abutment for screw attachment to a dental implant which allows seating of Ti bases at a user-selected rotation and tilt angle relative to the implant. This selected seating orientation is held prior to bonding the Ti base to the prosthesis by the multi-unit abutment during processing. At the time of installation, this capability can correct or reduce misalignments resulting from the accumulation of positioning errors in steps of the fabrication of the prosthesis relative to the initial position of the abutments. After installation, the multi-unit abutment has the capability to adapt to mechanical changes to maintain or improve passive fit by responding to mechanical stresses transferred through the prosthesis. In this manner, the final relative orientation of the adjustable abutment can be directly influenced by the positions of the Ti bases in the prosthesis or the position of the implants during the life of the installation.

[0025] Some embodiments of the invention include a multi-unit abutment that is assembled outside of the patient’s mouth, mounted onto a drive tool in a linear arrangement for attaching it to an implant, and then reoriented to have the abutment portion interface with a Ti base that is not aligned with the axis of the implant for processing. Subsequently a Ti base can be attached to the multi-unit abutment with a prosthetic screw.

[0026] Assembly of the swivel shell to the abutment base with the ball can be carried out at a factory or OEM site and provide a factory preset retention orientation force whereby theswivel shell against the ball is held at a desired orientation with the preset retention orientation force provided entirely by only the ball contact surface(s) with the swivel shell.

[0027] Some embodiments of the invention include a ball portion and a swivel portion that are capable of relative tilt or rotation but are constrained to not separate from one another. Some embodiments allow a desired force threshold for changing orientation of the ball and swivel to be fixed during manufacturing. In some embodiments, the multi-unit abutment can be installed in the implant by passing a drive tool through an aperture of the swivel. In some embodiments of the invention, this aperture includes threads for the prosthetic screw for attaching a Ti base. In some embodiments, the swivel includes features for snap locking to a Ti base.

[0028] One embodiment describes a system for alignment and attachment of a dental prosthesis to an implant with a prosthetic screw. The prosthetic screw has a head and a threaded shaft. The system includes: an abutment base having a longitudinal axis, the abutment base with a proximal end comprising a ball portion and an abutment base drive interface and a distal end having screw threads for attachment to the implant. The system also includes a swivel shell having an inner surface and an outer surface. The swivel shell includes a swivel aperture proximate the distal end and a threaded aperture at the proximal end. The threads are sized to engage the prosthetic screw shaft. The swivel shell is sized and shaped to resist (tilt / rotational) motion relative to the ball portion below a predetermined torque threshold.

[0029] One embodiment describes how the omnidirectional multi-unit abutment can be used in a method comprising: inserting the abutment drive tool tip through the swivel shell aperture to engage the abutment base drive interface; presenting the abutment base drive tool and multi-unit abutment assembly to the implant; rotating the abutment base drive tool to attach the abutment base to the implant to a first torque; disengaging the abutment base drive tool from the abutment base drive interface; moving the swivel shell to a different orientation; presenting a prosthesis comprising a Ti base to the implant abutment system; and attaching the prosthesis to the implant abutment with a prosthetic screw7.

[0030] Some embodiments describe a system for alignment and attachment of a dental prosthesis to an implant using a multi-unit implant abutment, the multi-unit implant abutment comprising:a ball and shell assembly comprising: a base comprising an abutment drive interface for screw attachment to the implant; the base comprising a first end having a ball and a second end with a threaded post with a longitudinal axis; and wherein the threaded post is designed to screw into a dental implant to a predetermined torque; a shell portion having an interior surface and an exterior surface; wherein the shell portion has a first end with an aperture and a second end has a threaded portion for a prosthetic screw; and wherein the ball is captured inside the shell portion with the threaded portion of the base post extending through the aperture; a Ti base comprising an aperture on the proximal end and an interface on the distal end designed to mount on the exterior of the shell portion in a known position; and a drive tool designed to engage the abutment drive interface, wherein the drive tool is capable of being inserted through the threaded portion of the shell.

[0031] One embodiment describes how a portion of a one-piece swivel shell can be deformed onto the ball with rotary swaging to constrain motion of the swivel, provide a higher contact area with the ball and to provide pressure on the ball from opposite sides to hold the swivel in position on the ball below a predetermined slip torque.

[0032] One embodiment describes a fabrication method of an omnidirectional multi-unit abutment comprising: inserting the ball portion of an abutment base inside a swivel shell, applying axial pressure to the ball to force its proximal side into intimate contact with the interior of the swivel shell deforming the wall at the opening of the swivel shell with metal forming, optionally rotary swaging, to capture the swivel shell on the ball portion.

[0033] This metal forming, such as, for example, a rotary swaging process, incorporates inelastic deformation of the swivel shell to reduce the aperture at the distal end of the swivel shell against the ball. Elastic deformation of the swivel shell interface with the ball provides a static frictional force that maintains the relative orientation of the two parts. This frictional force can be overcome with a slip torque above a design threshold determined by material selection, geometry, surface finish and rotary swaging process variables. For example, maintaining a minimum wall thickness at the distal aperture of the swivel shell after reducing the aperture size with rotary swaging is useful in maintaining consistent reorientation resistance. This also improves the sealing of the swivel shell to the ball in this area during installation in a patient’s mouth.

[0034] Some embodiments include adjustment to the alignment of an abutment to the copings of the prosthesis during installation or removal of a prosthesis in response to forces applied by the copings. In the case of screw-attached prostheses, the prosthesis may be manually pushed down on the abutments that are not fully aligned to direct them into sufficient seating to engage the prosthetic screws. Torquing the prosthetic screws is done without any tool holding the multi-unit abutment and results in fine tuning of the passive alignment. In the case of snap-on systems, the prosthesis may be intentionally moved to make attachment or release of one or more elements easier. After all snap connections are made, the localized compressive forces above a desired threshold on each abutment of a system may be designed to naturally redistribute without human intervention.

[0035] Embodiments of the present inventive concept provide a system for alignment and attachment of a dental prosthesis to an implant. The system includes: an abutment base having a longitudinal axis, a proximal end portion with a ball with an abutment base drive interface and a distal end with screw threads for attachment to the implant. The ball has an equator. The system also includes a swivel shell with a proximal end portion and an opposing distal end portion, an inner surface, an outer surface and a longitudinal axis. The swivel shell further includes an open internal channel extending along the longitudinal axis between the proximal end portion and the distal end portion. The swivel shell has an interference fit against the ball and contacts the ball at or above the equator of the ball and below the equator of the ball when the longitudinal axis of the abutment base is aligned with the longitudinal axis of the swivel shell whereby the swivel shell is able to tilt and rotate in response to forces applied to the swivel shell above a defined force. The swivel shell is configured to press against the ball with sufficient force to retain a desired tilt angle.

[0036] The swivel shell can have a deformable wall at a distal end portion thereof so that the deformable wall is configured to have a first configuration for assembly to the ball that deforms to a second configuration to capture the ball in the swivel shell whereby the swivel shell contacts the ball above and below the equator of the ball w hen the longitudinal axis of the abutment base is aligned with the longitudinal axis of the swivel shell.

[0037] The swivel shell can have a single piece monolithic metal body providing all ball contact surfaces. In the second configuration, the swivel shell can have a minimum wall thickness at the distal end portion that is in a range of about 0. 1 mm to about 0.25 mm.

[0038] A force above a defined value and applied in a distal direction to the dental prosthesis containing dental coping can result in a force applied to an interface with the swivel shell sufficient to change an orientation of the swivel shell relative to the ball.

[0039] The swivel shell can be configured to passively tilt and / or rotate relative to the ball when an applied torque of at or above 1 N-cm is applied thereto.

[0040] The inner surface of the swivel shell can define a contact surface with the ball above the equator when the longitudinal axes are aligned that is in a range of about 3 mm2and about 6 mm2, optionally in a range of about 4 mm2to about 6 mm2.

[0041] The system can further include a prosthetic screw. The open channel of the swivel shell can have threads sized and configured to engage the prosthetic screw. The prosthetic screw threadably engages the threads of the open channel of the swivel shell.

[0042] The open channel of the swivel shell can be devoid of screw' threads.

[0043] The system can further include a snap-on cap that is sized and configured to engage the proximal end portion of the swivel shell to attach the dental prosthesis to the abutment base. The snap on cap can be affixed to a Ti base coupled to an internal side of the dental prosthesis.

[0044] The system may include a snap-on cap that is sized and configured to engage the proximal end portion of the swivel shell. At least some of the proximal end portion of the swivel shell can reside inside the snap-on cap.

[0045] The swivel shell can be configured to be used without a lock screw to couple to the ball. The prosthetic screw is rotatable in the swivel shell to tighten to a prescribed torque and can cooperate with the swivel shell whereby the swivel shell alone provides a holding force against the ball to be at a desired angle relative to the ball. The swivel shell can hold the ball with sufficient force to allow' the prosthetic screw to be tightened in the swivel shell when the abutment base is attached to the implant.

[0046] The distal end portion of the swivel shell can be rotary swaged to capture the ball while applying an axial load to the swivel shell with the ball held in the swivel shell to form the second configuration whereby the swivel shell captures the ball by deforming the distal end of the swivel shell.

[0047] The system can further include a Ti base. The Ti base can have an aperture on the proximal end that is larger than a shaft of a prosthetic screw and smaller than a head of the prosthetic screw and a distal end that can be shaped to reside against a seating surface in the outer surface of the swivel shell.

[0048] The system can further include an orientation tool with an orientation post that extends into the open channel of the swivel shell to engage the swivel shell using threads of the swivel shell in the open channel that are configured to threadably engage a prostheticscrew and apply a force / torque sufficient to slidably move the swivel shell into a selected orientation with the ball.

[0049] The system can further include a resilient member residing between the proximal end of the ball and the distal end portion of the swivel shell thereby facilitating slip resistance and / or maintain a seal between the ball and swivel shell.

[0050] The swivel shell and ball can be sized and configured to provide attachment to the implant and dental prosthesis without a lock screw.

[0051] The open channel of the swivel shell can have threads sized and configured to directly engage a prosthetic screw or the open channel of the swivel shell is devoid of threads.

[0052] The swivel shell can be provided as a single piece monolithic metal body that provides a shaped inner surface extending about an internal cavity that holds and captures the ball and that can provide the contact surface against the ball above and below the equator of the ball when the longitudinal axis of the abutment base is aligned with the longitudinal axis of the swivel shell.

[0053] The swivel shell and ball are configured to slidably cooperate to allow a passive internal in situ change in alignment between the implant and / or the dental prosthesis postinstallation without direct external intentional manipulation of the swivel shell.

[0054] Other embodiments of the present invention are directed to a dental system for alignment and attachment of a full arch dental prosthesis to a plurality of dental implants. The system includes: a plurality of abutment bases, each abutment base having a longitudinal axis, the abutment base with a proximal end portion comprising a ball with an abutment base drive interface and a distal end with screw threads for attachment to the implant. The ball has an equator. The system also include a plurality of swivel shells, each swivel shell with a proximal end portion and an opposing distal end portion, an inner surface, an outer surface and a longitudinal axis. The swivel shell further includes an open channel extending along the longitudinal axis between the proximal end portion and the distal end portion. The open channel of the swivel shell has threads sized and configured to engage a prosthetic screw or the open channel of the swivel shell is devoid of threads. The swivel shell has a single piece monolithic metal body that provides a shaped inner surface extending about an internal cavity that holds and captures the ball and provides a contact surface against the ball above and below the equator of the ball when the longitudinal axis of the abutment base is aligned with the longitudinal axis of the swivel shell. At least some of the swivel shells cooperate to rotate relative to each other and relative to coupled abutment bases target implants define proper alignment at installation.

[0055] The system can be configured to allow passive in situ change in alignment between the implants and / or the full arch dental prosthesis post-installation without direct external intentional manipulation of the swivel shell.

[0056] The swivel shells can have deformable distal end portions that deform to capture the ball post assembly to the corresponding swivel shell and allow a factory' preset orientation retention force to be set for a desired orientation.

[0057] Still other embodiments are directed to a system for alignment and attachment of a dental prosthesis to a dental implant. The system includes: an abutment base having a longitudinal axis and a proximal end portion with a ball with an abutment base drive interface and a distal end with screw threads for attachment to the implant. The ball has an equator. The system also includes a swivel shell with a proximal end portion and an opposing distal end portion, an inner surface, an outer surface and a longitudinal axis. The swivel shell further includes an open internal channel extending along the longitudinal axis between the proximal end portion and the distal end portion. The swivel shell is configured to capture the ball to prevent axial movement relative to the longitudinal axis of the abutment base and provide a desired tilt orientation in a range of about 0 degrees to about 30 degrees. Wherein, at assembly, the swivel shell captures the ball as a result of upper and lower hemisphere forces on the ball from contact with the ball above and below the equator of the ball when the longitudinal axis of the abutment base is aligned with the longitudinal axis of the swivel shell providing a frictional engagement therebetween whereby a swivel shell minimum orientation retention force is factory preset.

[0058] The swivel shell can have a distal end wall segment that inelastically deforms to contact the ball thereat.

[0059] The distal end wall segment can seal against the ball.

[0060] The swivel shell can be a single piece monolithic body providing all surface contact with the ball whereby the swivel shell has an interference fit against the ball and contacts the ball at or above the equator of the ball and below the equator of the ball when the longitudinal axis of the abutment base is aligned with the longitudinal axis of the swivel shell whereby the swivel shell is able to tilt and rotate in response to forces applied to the swivel shell above a defined force, and the swivel shell can be configured to press against the ball with sufficient force to retain a desired (preset) tilt angle.

[0061] The swivel shell can have a deformable wall at a distal end portion thereof so that the deformable wall is configured to have a first configuration for assembly to the ball that deforms to a second configuration to capture the ball in the swivel shell, and the swivel shellcan provide contact forces against the ball above and below an equator of the ball when the longitudinal axis of the swivel shell and the longitudinal axis of the post are aligned.

[0062] The swivel shell can have a single piece monolithic metal body and, in the second configuration, the swivel shell can have a minimum wall thickness at the distal end portion that is at least about 0.1 mm.

[0063] The system can further include a dental coping. The dental coping can be sized and configured to enclose part of the swivel shell. The dental coping can have a mounting interface a distal end thereof configured to mount on a seating surface on the exterior surface of the swivel shell. The one or more drive tools is / are capable of being inserted through an aperture in the dental coping to engage the abutment drive interface or threading in an open channel of the swivel shell.

[0064] The swivel shell can have a proximal end portion configured to engage a snap-on coping, and the snap-on coping can include a compressible structure.

[0065] A force applied in a distal direction to the dental prosthesis containing an embedded coping can result in a force applied to an interface with the swivel shell sufficient to change an orientation of the swivel shell relative to the ball.

[0066] The system can further include a coping with a tapered outer surface. The force applied in the distal direction can be applied to the tapered outer surface, which then applies the force to the swivel shell to change the orientation of the swivel shell relative to the ball.

[0067] Yet other embodiments are directed to a system for alignment and attachment of a dental prosthesis to a dental implant that includes: an abutment base having a longitudinal axis, the abutment base including a proximal end portion with a ball with an abutment base drive interface and a distal end with screw threads for attachment to the implant. The ball can have or define an equator. The system also includes a swivel shell with a proximal end portion and an opposing distal end portion, an inner surface, an outer surface and a longitudinal axis. The swivel shell can also have an open internal channel extending along the longitudinal axis between the proximal end portion and the distal end portion. The open internal channel has threads sized and configured to engage external threads of a prosthetic screw. The swivel shell slidably holds the ball and contacts the ball above and below the equator of the ball when the longitudinal axis of the abutment base is aligned with the longitudinal axis of the swivel shell. The swivel shell is configured to capture the ball to prevent axial movement relative to the longitudinal axis of the abutment base and provide a desired tilt orientation in a range of about 0 degrees to about 30 degrees.

[0068] The swivel shell captures the ball prior to assembly as a result of upper and lower hemisphere forces on the ball whereby a swivel shell minimum orientation retention force can be factory preset independent of (without) any lock screw.

[0069] The swivel shell can have a distal end wall segment that inelastically deforms to contact the ball thereat thereby forming a seal.

[0070] The distal end wall segment can seal against the ball.

[0071] Some embodiments of the invention include a multi-unit abutment for screw attachment to a dental implant which allows seating of Ti bases at a user-selected rotation and tilt angle relative to the implant. This seating orientation can be fixed prior to bonding the Ti base to the prosthesis, and in some embodiments can be adjusted while the Ti base is otherwise held onto the abutment. In this manner, the final relative orientation of the adjustable abutment can be directly influenced by the fixed position of the Ti bases in the prosthesis. This can correct or reduce misalignments resulting from the accumulation of positioning errors in steps of the fabrication of the prosthesis relative to the initial position of the abutments.

[0072] Some embodiments of the invention include a multi-unit abutment that is assembled outside of the patient’s mouth, mounted onto a drive tool in a linear arrangement for attaching it to an implant, reorienting the abutment portion that interfaces with a Ti base that is not aligned with the axis of the implant. Subsequently a Ti base can be attached to the multi-unit abutment with a prosthetic screw.

[0073] Some embodiments of the invention include a ball portion and a sw ivel portion that are capable of relative tilt or rotation but are constrained to not separate from one another. Some embodiments allow the relative orientation of the ball and swivel to be fixed by applying pressure on opposite sides of the ball portion equator in the absence of a lock screw. Some embodiments maintain pressure on opposite sides of the ball in the absence of a locking screw. In some embodiments, the multi-unit abutment can be installed in the implant by passing a drive tool through an aperture of the swivel shell.

[0074] Although screw attachment of the prosthesis is preferred, some embodiments of the invention provide a multi-unit abutment with angular adjustment capability that uses a snap- on coupling as an alternative to a prosthetic screw7.

[0075] One embodiment describes a system for alignment and attachment of a dental prosthesis to an implant with a prosthetic screw, wherein the prosthetic screw7comprises a head and a threaded shaft, the system including: an abutment base having a longitudinal axis, the abutment base having a proximal end comprising a ball portion and an abutment basedrive interface and a distal end with screw threads for attachment to the implant; and a swivel shell having an inner surface and an outer surface. The swivel shell includes a swivel aperture proximate the distal end and a threaded aperture at the proximal end.

[0076] Embodiments of the present disclosure provide a swivel shell that has a portion that is deformable onto the ball, optionally with rotary swaging, to capture the swivel shell, provide a higher contact area with the ball and to provide pressure on the ball from both sides of the equator provided by the swivel shell to hold the swivel shell in position without tightening a lock screw to limit axial movement and / or hold a relative tilt angle.

[0077] One embodiment describes a fabrication method of an omnidirectional multi-unit abutment that includes: inserting the ball portion of an abutment base inside a swivel shell, applying axial pressure to the ball to force its proximal side into intimate contact with the interior of the swivel shell; and deforming the opening of the swivel shell to capture the swivel shell on the ball portion.

[0078] The deforming can be performed using a rotary7sw aging process that can incorporate inelastic deformation of the swivel shell to reduce the aperture at the distal end of the swivel shell and force the swivel shell against the ball. The interference fit of the swivel shell with the ball provides a static frictional force that maintains the relative orientation of the two parts without tightening any locking screw7. This frictional force can be overcome with a slip torque above a design threshold determined by material selection, geometry, surface finish and rotary swaging process variables. For example, maintaining a minimum wall thickness at the distal aperture of the swivel shell after reducing the aperture with rotary7swaging is necessary7to maintain consistent reorientation resistance. This also improves the sealing of the swivel shell to the ball in this area during installation in a patient’s mouth.

[0079] Some embodiments describe a system for alignment and attachment of a dental prosthesis to an implant using a multi-unit implant abutment, the multi-unit implant abutment including: a ball and shell assembly w ith a base comprising an abutment drive interface for screw7attachment to the implant. The base has a first end having a ball and a second end w ith a threaded post with a longitudinal axis. The threaded post is designed to screw into a dental implant to a predetermined torque. The ball and shell assembly also has a shell portion having an interior surface and an exterior surface. The shell portion has a first end with an aperture and a second end has threading for a prosthetic screw7. The ball is captured inside the shell portion using metal forming, optionally rotary swaging, proximate the aperture of the shell portion with the threaded portion of the base post extending through the aperture. The system also includes a Ti base with an aperture on the proximal end and an interface on thedistal end designed to mount on the exterior of the shell portion in a known position; and one or more drive tools designed to engage the abutment drive interface and the prosthetic screw.

[0080] Some embodiments of the invention describe a multi-unit implant abutment system for alignment and attachment of a dental coping to a dental implant, the multi-unit implant abutment including: a ball and shell assembly having a base with a proximal end comprising a ball portion and an abutment drive interface for rotating the base for screw attachment to the implant, and a distal end comprising a threaded portion for mating with threads of the implant, and having a shell with a distal portion including a distal shell aperture. The distal shell aperture is sized and shaped around the ball portion to prevent passage of the ball portion of the base through the distal shell aperture. The abutment drive interface is accessible to a drive tool inserted through the aperture of the shell.

[0081] Some embodiments include fine tuning of the alignment of an abutment to the copings of the prosthesis. In the case of screw-attached prostheses, the prosthesis may be manually pushed down on the abutments that are not fully fixed in position to direct them into more passive seating before inserting a prosthetic screw. In the case of snap-on systems, the prosthesis may be used without compressive fixing to reorient the abutments using a coping with either a zero-retention processing insert or without any retention insert applied for initial alignment before attachment with final retention inserts. In this case, the localized compressive forces on each abutment of a system will naturally redistribute without extemal / intentional human intervention above a predetermined force threshold. That is, after the final coping is snapped into position, the force-redistributed multi-unit abutment orientations will redistribute unbalanced forces above the slip torque.

[0082] For the purposes of this disclosure, a “dental prosthesis” is defined broadly to be anything that incorporates multiple dental copings or Ti bases that can be mounted and removed from at least three implant abutments. Different Ti base designs are known in the dental industry, and the systems and methods disclosed here can be adapted to work with many commercially available types of Ti bases including pick-up copings, temporary cylinders, inserts and impression copings. Implant abutments are known in the dental industry having compatible interfaces to these Ti bases. Since the mechanical interface is the same, for the purposes of this disclosure, implant abutment is considered a generic term that includes abutment analogs. Description of abutment alignment systems and process methods with Ti bases and implants that are installed in a patient’s jaw should be considered to also describe equivalent inventive concepts that may be used with Ti bases and implant analogs in a dental lab. A common geometry' comprises a conical Ti base seated to a conical implantabutment. Although this form of system is used in the figures and discussion below, the inventive concepts may also be applied to other types of Ti bases and abutments. The inventive concepts are not limited to Ti bases or copings that are attached to abutments with prosthetic screws. Features may also be applied to various snap-on systems, including those that include a coping with a deformable retention insert that is reversibly retained by compressive forces on a multi-unit abutment. This type will be discussed, but the inventive concepts can be adapted to other snap-on systems that do not include discrete retention inserts. For the purposes of this disclosure, the terms '‘coping” and “Ti base” are used generally and interchangeably for all of these structures that are used to align and seat prostheses with implant abutments.

[0083] The inventive concepts disclosed herein can be used with different types of dental prostheses. The dental prosthesis can be any form of impression used in a dental lab to assist in creating and testing dental prostheses. A dental prosthesis can also be one fabricated in the dental lab using a physical model made from the impression, a dental prosthesis newly fabricated, or an existing prosthesis being converted for screw attachment. A dental prosthesis is defined to include any multiple-tooth bridge or denture. These prostheses may incorporate Ti bases to provide a separable interface to provide orientation with an appropriate abutment attached to a patient’s jaw or gingiva. The multi-unit abutments for use with the inventive concepts disclosed herein include screw threads to mount the prosthesis with Ti bases onto the abutments and the abutments into the implants. While the concepts describe the typical male threads in the multi-unit abutment mating with female threads on the implant, this is for convenience in disclosure. Unless explicitly stated or restricted by functional necessity, some inventive concepts may be applied with systems having female threads in the multi-unit abutment engaging a screw with male threads in an implant. These are considered to be straightforward variations of the inventive concepts. One benefit of preferring the typical female threading of the implant for abutment attachment is standardization and implementation flexibility. For the same reasons, prosthetic screws with male threads and commercially available Ti bases are preferred but may not be required to gain some benefit from inventive concepts disclosed. These types of variations are considered to be within the scope of this disclosure.

[0084] The systems and methods disclosed herein can be used wi th prostheses for attachment to implants in both the upper and lower jaw. As a result, portions of the system that are oriented downward for the lower jaw will be oriented upward for the upper jaw and vice versa. For convenience, a disclosure of an embodiment of inventive concepts that is limitedto a single jaw orientation, is considered to disclose an embodiment for the opposite jaw orientation. When referring to the perspective of a clinician, proximal portions are nearer to the clinician than distal portions. While a term such as top is the opposite of the term bottom, and proximal is the opposite of distal, their actual relative orientation will be determined by the context of their use. The term tissue-side is used interchangeably with intaglio to indicate the side of a prosthesis that is opposite the occlusal or cameo surface.

[0085] The inventive systems disclosed are beneficially applicable to screw-attached prostheses and abutments. Key benefits of screw-attachment are variable tightening torques and reversibility. The terms permanent, semi-permanent, definitive and final when referring to screw-attachment are used interchangeably in this disclosure. A conventional screw that is definitively attached can still be removed by accessing the screw and rotating it in the opposite direction that was used for attachment. For the purposes of screw-attached prostheses for this disclosure, the attachment is semi-permanent, permanent or definitive in the sense that frequent attachment and removal is not anticipated for normal use. In contrast, a temporary screw attachment is applied for a planned process duration or other anticipated interval. The positioning of the Ti bases in the dental prosthesis may be effectively performed with a lift-off process using the temporary screws disclosed in co-owned US Patent 11,311,354, which is herein incorporated by reference in its entirety7. However, the utility of inventive concepts in this disclosure are not dependent upon using the system or methods disclosed in the referenced patent.

[0086] Screw attachment of an abutment to an implant is also described in the embodiments. However, some of the disclosed concepts may readily be adapted to other systems that do not utilize screw attachment of dental components to other elements such as implants including snap-on, magnetic attachment, or even adhesive attachment systems. Although less flexible, the implant and abutment may be assembled prior to presentation to the patient or features of the abutment may be directly incorporated into the implant while still benefiting from angular adjustability concepts disclosed with separate abutments and implants. These modifications are considered to be obvious variations of the inventive concepts described in the current disclosure.

[0087] Removal of a semi-permanent or definitive screw is generally motivated by a problem or an opportunity7for an improvement. Access to the screw to apply a tool for removal may require removal of material covering the screw that was added for aesthetic reasons. Some embodiments provide for re-alignment of the orientation of the multi-unit abutment when the prosthesis is positioned on the multi-unit abutment with a semi-permanent or definitive screwin place. This may improve passive fit of the prosthesis to implants when initially installed or after the system has been used for an extended period of time. While the implant abutments are generally used initially to position the Ti bases in the prosthesis, individual alignment errors will necessarily accumulate during subsequent processing or over time. The apparatus and methods disclosed below allow7the set of Ti bases in the prosthesis to be aligned to the set of the multi-unit abutments to improve and maintain the overall passive fit without intervention by a dental professional.

[0088] Elements disclosed herein may be characterized as having an axis or a longitudinal axis. In the case of a long cylindrical object like a pencil, the longitudinal axis is unambiguously through the center of the cylinder from the writing end to the eraser end of the pencil. The longitudinal axis is traditionally considered to be along the length or longest dimension of an object characterized by length, width and thickness in descending dimensional magnitude. If instead of a pencil, a threaded bolt is considered, the axis or even longitudinal axis may be considered to be through the center from the engaging end of the threads through the center of the head of the bolt. The rotational axis in this case and the longitudinal axis are the same even for stubby bolts. In this disclosure, the axis or longitudinal axis of an object with screw threads will be the same as the rotational axis of the threading. Widths will be measured perpendicular to this rotational axis. Thus, a traditional nut with interior threads would be considered to have a longitudinal axis through the middle of the central aperture, i.e., where the matching bolf s axis would be located when engaged. By extension, a washer without threads captured betw een a bolt and a nut would also be considered to have a longitudinal axis or simply an axis centered in the aperture and perpendicular to the plane of the w asher. For the purposes of this disclosure, a linear assembly of components results from having the component axes of the assembly in a roughly colinear arrangement. Thus, an assembly comprising a bolt with a w asher and nut would be a linear assembly even if the axis of the w asher can move around the shared axes of the bolt and nut due to the washer aperture being larger than the w idth of the threaded section of the bolt. External threading is generally characterized as having a minor diameter measured at the root of the threads and a major diameter measured at the crest of the threads. Internal threading is generally characterized as having a minor diameter at the crests and a major diameter at the roots. Unless otherwise specified, the width of the external threads on a bolt stem is defined to be the major diameter or maximum deviation from the bolt’s axis, that is, what would be measured with calipers. The width of the internal threads of a nut isdefined to be the minor diameter of the internal threads or minimum deviation from axis of the nut. that is, what could be measured with a pin or plug gauge.

[0089] In this disclosure some threaded elements that tighten by relative rotation may have some characteristics that could be considered nut-like and others that are screw-like, such as elements having both female and male threading. The term screw will be used generically in this disclosure for these threaded elements in discussing the inventive concepts. However, external threading on a screw will be considered to be male and internal threading will be considered to be female. The phrases screwing into and threading into are used for male and female parts. That is, screwing a first piece into a second piece does not require the first piece to have male threads. A conventional bolt may be generally described as being threaded into or onto a conventional nut when their threads are engaged in this disclosure unless clearly restricted

[0090] For the purposes of this disclosure, the term “ball” means a mechanical structure that includes some geometric attributes of a sphere. It is a more generic term that allows for only- some portions of the surface of the ball having essentially spherical surfaces while other portions can deviate significantly from having spherical surfaces. Spherical surfaces are preferred for some of the orientational flexibility and sealing of the contact surfaces between a ball and a structure that can be repositioned and locked in position relative to the ball perhaps by swiveling. The term “shell” (used interchangeably with “swivel” and “swivel shell”) is something that at least partially surrounds a ball. Contacting surfaces between the exterior of a ball and the interior of a shell are preferably spherical surface segments of about the same diameter for increased frictional grip w hen starting the fixing process or for providing a sealing surface to block the interior of the assembly from biological contamination. Including structures or deviations ty pically having a smaller size than the spherical radius may be included to improve sealing or tailor resistance to movement between a ball and a shell compared to smooth spherical mating surfaces. While having the flexibility to position the axis of a prosthetic screw and Ti base without restriction up to an angle of 30 degrees with respect to the axis of an implant and at any rotation angle around either axis may be preferred, mating elements of the implant, ball, shell or Ti base may be designed to restrict this omnidirectional angular flexibility-. Such restrictive modifications are known in the art and may be used with some inventive concepts disclosed here. The structures with spherical surface portions in this disclosure are generally characterized by a linear axis due to their threaded interfaces. In analogy to the planet earth, ball structures may be considered to have a northern and a southern hemisphere separated by an equator perpendicular to thelinear axis at the center of the ball. In this disclosure, hemispheres are not required to be ideal geometric structures that are exactly half of an ideal geometric sphere; a hemisphere may refer to only a smaller portion of a theoretical sphere. In the drawings, the northern or upper hemisphere is generally illustrated as the proximal hemisphere and the southern or lower hemisphere as the distal hemisphere. Shell structures with spherical interior surface portions surrounding a ball may be described as having proximal and distal hemispheres similar to how the earth’s atmosphere surrounding the earth’s crust can be separated into northern and southern atmospheric hemispherical layers. The equator of the shell would be located between the hemispheres in a plane perpendicular to the longitudinal axis of the shell. Some shell structures in this disclosure have interior spaces that include a hemispherical surface hollow section merged proximate the equator with a cylindrical void of at least the same diameter. The cylindrical void allows this type of shell to be moved axially over the ball portion of an abutment base to have a portion of the hemisphere of the ball contact the hemispherical hollow of the shell.

[0091] For the purposes of this disclosure, the term “one-piece” applied to a component should be interpreted as having no parts that form the functional feature(s) that are not integrally formed. That is, a one-piece component has no mechanical joints or seams in any portion for a specific function identified for the component that benefits from being one- piece. In this disclosure, a one-piece shell provides a one-piece integral monolithic body with spherical clamping potions and without any seam (devoid of any seam) between parts in the contact area on both sides of a ball equator or that forms all ball contact surfaces to form continuous sealing as the term is used in this disclosure. Thus, to be clear, the term “one- piece” with reference to the shell does not exclude a monolithic structure that has an addition of another component that is not essential for the interface characteristics of the spherical clamping interface. There may be interfaces on a one-piece part for joining to other parts in a higher assembly, but that higher assembly would not represent a one-piece part when assembled. One-piece parts are monolithically constructed of a single piece of continuous material, but the shape may change without modifying its one-piece character. This disclosure includes descriptions of a one-piece shell comprising spherical clamping surface portions on both sides of a ball equator to form continuous ring seals in both spherical surfaces above and below the equator of the ball. Although the one-piece shell is necessarily modified in shape to create these interface portions with the ball, it remains a single piece of continuous material throughout this process. The shell remains one-piece but is part of a multiple-piece assembly with the ball. In contrast, if a shell is formed around a ball bymechanically bonding or welding two shell portions together, their assembly does not result in a one-piece shell providing one-piece spherical clamping potions on both sides of a ball equator to form continuous ring seals as the term is used in this disclosure.

[0092] For the purposes of this disclosure, the term “to fix one part in position” means to maintain the relative position of that part with respect to another part sufficiently for a purpose. That is, the degree of fixing is variable depending on the desired resistance to movement for processing or use. Fixing should not necessarily be interpreted as a permanent state of relative position unless the fixing is described as being explicitly done with a typically permanent process such as welding. In many parts of this disclosure, orientational fixing results from mechanical forces and frictional resistance to movement. Parts that are fixed for one step in a process may be reoriented with the application of sufficient force for a subsequent step. The context of the discussion should be considered in interpreting the degree of fixing desired. Note that parts may be constrained to not allow relative translation or separation from one another without having their relative angular orientations permanently fixed in position.

[0093] It is common in prosthodontics to secure threaded elements to a desired torque or to have some elements fastened to a higher or lower torque than some other combination of elements. For example, if three elements are screw ed together in sequence, it is common to prefer that the first two are assembled with a higher torque so that the third element can be attached or removed without affecting the attachment of the first two. In some cases, torques are quantified with torque wrenches and sometimes the experience of the practitioner is used to determine w hen the torque is sufficient for functioning as desired. For the purposes of this disclosure, these torques will be considered to be predefined whether assessed in a quantitative or a qualitative manner. If a quantitative minimum torque value or acceptable range is specified to be essential, measurement with a tool or with some indication structure built into the parts is expected. In some embodiments, it may be desirable to prevent excessive torquing that could cause structural or biological stress on the implant seating or prosthesis through controlled failure of sacrificial elements. This controlled mechanical failure may result from both intentionally weakened structures or characterization of inherent failure characteristics of uniform structures. In other cases, practical minimum torques may be obtained by limiting thread lengths so that relative rotation is stopped by threads bottoming out. Different desired or predetermined torque levels may be used in a quantitative or qualitative sense to provide different levels of relative orientational fixing between parts. For example, the desired torque may represent any torque in a range between the minimumamount of torque such that parts will not reorient due to gravity and the maximum amount of torque that still allows parts to move relative under an applied force from contact with another part, such as a seating force applied to a prosthesis coping in contact with a multi-unit abutment. The actual magnitude of the desired torque will depend upon physical characteristics and the application environment. The resulting desired level of holding or fixing will naturally follow from the context of why and how the torque is being applied.

[0094] For the purposes of this disclosure, “surface contact area” should be interpreted from a macroscopic perspective unless explicitly otherwise specified. An example may be useful in understanding this term. If a small metal plate is placed on top and in the middle of a much larger plate, the surface contact area of these two elements as used herein will simply be the bottom face area of the smaller plate. Due to small variations in planarity, machining tolerances or surface roughness, it is appreciated that there will be some places between the plates that are filled with air where there is not intimate contact between the plates. Some of this air could be removed by applying sufficient pressure with a hydraulic press, but from a macroscopic perspective, the surface area would not increase as the term is generally construed in this disclosure.

[0095] Other terms in the specification and claims of this application should be interpreted using generally accepted, common meanings qualified by any contextual language where they are used. The terms "a" or "an", as used herein, are defined as one or as more than one. The term "plurality", as used herein, is defined as two or as more than two. The term "another", as used herein, is defined as at least a second or more. The terms "including" and / or "having", as used herein, are defined as comprising (i. e. , open language). The term "coupled", as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. The terms “about” and “essentially” mean ±10 percent. As used herein, phrases such as "between X and Y" and "between about X and Y" should be interpreted to include X and Y. As used herein, phrases such as "between about X and Y" mean "between about X and about Y." As used herein, phrases such as "from about X to Y" mean "from about X to about Y." Reference throughout this document to "one embodiment", "certain embodiments", and “an embodiment" or similar terms means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of such phrases or in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments without limitation. The term "or" as used hereinis to be interpreted as an inclusive or meaning any one or any combination. Therefore, "A, B or C" means any of the following: "A; B; C: A and B; A and C: B and C: A, B and C". An exception to this definition will occur only when a combination of elements, functions, steps or acts are in some way inherently mutually exclusive.

[0096] The drawings featured in the figures are for the purpose of illustrating certain convenient embodiments of the present invention and are not to be considered as limitation thereto. The term ‘'means’7preceding a present participle of an operation indicates a desired function for which there is one or more embodiments, i.e., one or more methods, devices, or apparatuses for achieving the desired function and that one skilled in the art could select from these or their equivalent in view of the disclosure herein and use of the term “means’’ is not intended to be limiting. Other objects, features, embodiments and / or advantages of the invention will be apparent from the following specification taken in conjunction with the following drawings.BRIEF DESCRIPTION OF THE FIGURES

[0097] FIG. 1 is a schematic perspective view of the application environment of a prior art dental prosthesis incorporating four aligned Ti bases and a jaw with three aligned implants and one misaligned implant.

[0098] FIG. 2 is a side cross-sectional view of a portion of FIG. 1 containing one aligned and one misaligned Ti base implant abutment pair including prior art fixed angle multi-unit implant abutments.

[0099] FIG. 3 is a side cross-sectional view oof an embodiment of the self-adjusting omnidirectional multi-unit abutments according to inventive concepts of the present disclosure.

[0100] FIG. 4 is a top exploded isometric view of a self-adjusting omnidirectional multi-unit abutment assembly for prosthetic screw coping attachment according to embodiments of the invention.

[0101] FIG. 5 is a bottom exploded isometric view of an embodiment of the self-adjusting omnidirectional multi-unit abutment assembly for prosthetic screw coping attachment shown in FIG. 4.

[0102] FIG. 6 is a top isometric assembled view of the self-adjusting omnidirectional multiunit abutment assembly for prosthetic screw coping attachment shown in FIG. 4.

[0103] FIG. 7 is a bottom isometric assembled view' of the embodiment of a self-adjusting omnidirectional multi-unit abutment assembly for prosthetic screw coping attachment shown in FIG. 4.

[0104] FIG. 8 A is a cross-sectional view of the self-adjusting omnidirectional multi -unit abutment assembly of FIG. 4 prior to ball capture forming / assembly. .

[0105] FIG. 8B is a cross-sectional view of the self-adjusting omnidirectional multi-unit abutment assembly of FIG. 4 after ball capture forming / assembly.

[0106] FIG. 9 is an enlarged view of the lower portion of the self-adjusting omnidirectional multi-unit abutment assembly of FIG. 8 A prior to assembly.

[0107] FIG. 10 is an enlarged view of the lower portion of the self-adjusting omnidirectional multi-unit abutment assembly of FIG. 8B after ball capture forming / assembly.

[0108] FIG. 11 is a cross-sectional view of the of the self-adjusting omnidirectional multiunit abutment assembly for prosthetic screw coping attachment of FIG. 4 shown in a linear arrangement mounted on an implant drive tool for attachment to an implant according to embodiments of the present invention.

[0109] FIG. 12 is a cross-sectional view of the of the self-adjusting omnidirectional multiunit abutment assembly for prosthetic screw coping attachment shown in FIG. 11 but illustrating the assembly with attachment of a Ti base with a prosthetic screw.

[0110] FIG. 13A is a first in a sequence of cross-sectional views illustrating redirection of swivels in response to attachment of a prosthesis with embedded Ti bases.[OHl] FIG. 13B is the second in a sequence of cross-sectional view s illustrating redirection of swivels in response to attachment of a prosthesis with embedded Ti bases.

[0112] FIG. 13C is the third in a sequence of cross-sectional views illustrating redirection of swivels in response to attachment of a prosthesis with embedded Ti bases.

[0113] FIG. 13D is the fourth in a sequence of cross-sectional views illustrating redirection of swivels in response to attachment of a prosthesis with embedded Ti bases.

[0114] FIG. 14 is a cross-sectional view of an of a self-adjusting omnidirectional multi-unit abutment assembly for prosthetic screw coping attachment incorporating a spring washer according to embodiments of the present invention.

[0115] FIG. 15 is a top exploded isometric view' of an example self-adjusting omnidirectional multi-unit abutment using a snap-on coping according to embodiments of the present invention.

[0116] FIG. 16 is top isometric assembled view of the self-adjusting omnidirectional multiunit abutment using a snap-on coping shown in FIG. 15.

[0117] FIG. 17 is a bottom isometric assembled view of the self-adjusting omnidirectional multi-unit abutment using a snap-on coping shown in FIG. 16.

[0118] FIG. 18 is a side plan view of the self-adjusting omnidirectional multi-unit abutment using a snap-on coping shown in FIG. 16.

[0119] FIG. 19 is a cross-sectional view of the self-adjusting omnidirectional multi-unit abutment using a snap-on coping of FIG. 17 taken along line A-A through the longitudinal axis.

[0120] FIG. 20 is a cross-sectional view of the application environment of a representative embodiment of the self-adjusting omnidirectional multi-unit abutment with snap-on coping including prosthesis shown in FIG. 16 and coupled to a dental implant according to embodiments of the present invention.

[0121] FIG. 21 is a cross-sectional view of an orientation post attached to a swivel shell of the self-adjusting omnidirectional multi-unit abutment according to embodiments of the present invention.DETAILED DESCRIPTION

[0122] There are multiple embodiments included in this disclosure to illustrate options for providing the benefits of a self-adjusting omni-directional multi-unit abutment. FIG. 3 shows the application environment of a first embodiment of a self-aligning omni-directional multiunit abutment 100 (“SA-MUA”). FIG. 3 shows the SA-MUA system as comprising at least two SA-MUAs, similar to the orientation of FIG. 2 for the fixed 0-degree multi-unit abutment 220 at the location of the angled implant 216. In use, , the alignment of the seating surface 22 of the Ti base 5 may not align with the seating surface 122 of the self-aligning omnidirectional multi -unit abutment 100. However, as shown in FIG. 3, further tightening of the prosthetic screw 6 provides a torque on the self-aligning omni-directional multi -unit abutment 100 that results in a pivoting action to align conical surface 94 with the matching taper of the Ti base 5. This angular adjustment results from the self-aligning omnidirectional multi -unit abutment 100 responding to the orientation of the Ti base 5 embedded in the dental prosthesis 68. The construction of the self-aligning omni-directional multi-unit abutment 100 providing the pivoting and swiveling that provide this controlled response will be described in detail below. While possible to use both fixed and self-aligning multi-unit abutments, replacing all conventional fixed angle multi-unit abutments with the self-aligning omni-directional multi-unit abutments 100 is preferred since FIGS. 1 and 2 assumed the unrealistic assumption of perfect alignment of all but one of the multi-unit abutments with all of the Ti bases in the dental prosthesis aligned perfectly.

[0123] FIGS. 4 and 5 show the self-aligning multi-unit abutment 100 prior to assembly of the two components. It comprises a swivel shell 190 having a prosthetic screw thread 8 on the proximal end and an aperture 193 at the distal end and an abutment base 81. The abutment base 81 has a ball (also interchangeably referred to as a “ball portion) 82 on the proximal end and a distal end with threading 14 for attachment to an implant 16. The ball 82 also includes a drive feature 60 to engage a tool to drive the abutment base 81 into the implant threads. As shown in FIGS. 6 and 7. aperture 193 is sized to allow the ball portion 82 of the abutment base 81 to be inserted inside the swivel shell 190. The internal structure and interfaces between the swivel shell 190 and abutment base 81 is more clearly seen in FIGS. 8 A and 8B than the perspective views of FIGS. 6 and 7.

[0124] Referring now to FIGS. 8A, 8B, 9 and 10, the swivel shell 190 in FIG. 8A is illustrated pre-assembly and includes a distal wall end 190D and an initial distal aperture shape 193 and an interior curvature portion 96 which is sized and shaped to essentially match the curvature 89 of the ball portion 82 of the abutment base 81. The swivel 190 illustrated includes internal threading 8 for attaching to the external threads 87 of the prosthetic screw 6. It also includes a Ti base seating feature 122 for supporting and orienting the Ti base 5 when it is mounted with the prosthetic screw 6 to the omnidirectional multi-unit abutment 100 (the combination assembly of the abutment base 81 with ball 82 captured in shell 190). The average outer diameter of the seating feature 122 is typically in a range of about 4 mm to about 6 mm.

[0125] FIG. 8A includes a dotted line labeled as “eq” which represents the equator of the ball 82 and the equator of a matching spherical surface towards a proximal end of the swivel shell 190. The equator is located in a plane perpendicular to the longitudinal axis of the parts at the center of the spherical surfaces. Note that the illustrated ball portion 82 is spherical above the equator up to the location of the edges of the drive feature 60. The illustrated ball 82 is spherical in its lower hemisphere below the equator until the waist 95. The waist 95 connects the ball 82 to the low er portion of the abutment base 81. The waist 95 can limit motion of the swivel shell 190 relative to the longitudinal axis of the abutment base 81.

[0126] The figures and cross-sections shown illustrate an embodiment where the swivel shell 190 may be positioned and rotated anywhere within a + / - 30-degree cone. The tilt magnitude and orientations of adjustment allow ed are a design choice, although 30 degrees of tilt is generally sufficient for most clinical applications. In FIG. 8A, the interior of the swivel shell has a hemispherical surface 96 corresponding to / matching the curvature 89 of the ball 82 and extending above the equator until it reaches the internal threading 8 for the prosthetic screw.Although the threading 8 is show n as extending throughout the swivel shell 190 in the aperture region proximal to the ball 82, the threading may be restricted to a portion of this distance. Of course, the thread length 8 must be longer than the maximum engagement of the threads of the prosthetic screw- 6 necessary to affix the Ti base 5. The distal end of the shaft of the prosthetic screw 6, where used, must not extend to interfere with the swivel 190 motion relative to the ball 82.

[0127] Referring to FIG. 8A and 9, the initial distal aperture shape 193 of the swivel shell 190 has a diameter sufficient to allow the ball portion 82 of the abutment base 81 to be inserted into the initial distal aperture shape 193 of the swivel shell 190 until contact is made with the spherical interior surface 96 of the swivel shell proximate the distal end of threads 8 as shown in the cross-sectional view of FIG. 8 A. In this case, there is no restriction on the width of the abutment base below the ball 82 or on the minor diameter of the internal threading 8 of the swivel 190 as in some prior art multi-unit abutments. As shown in FIG. 8B, after insertion, the initial distal aperture 193 is reduced in size to capture the ball 82 inside the swivel shell 190 and form multi-unit abutment 100.

[0128] FIGS. 9 and 10 illustrate how the initial distal end wall segment 90W (FIG. 9) of the swivel shell 190 is inelastically deformed to produce a reduced final distal aperture shape with deformed distal end w all segment 91 W (FIG. 10).

[0129] FIG. 12 is a cross-sectional view that illustrates the final assembly of parts in this embodiment including coping 5 and prosthetic screw 6. The interior surface profile 96 of the shell 190 has a curvature matching curvature 89 of the ball portion 82 of the base 81 . Note that this example configuration provides spherical contact surface portions that are diametrically opposed. The swivel shell 190 contacts the ball 82 above and below the equator (shown as the dotted line in FIG. 8A, 8B) of the ball 82. Referring to FIG. 8B, when longitudinal axes are aligned, the swivel shell 190 presses against the ball portion 82 in both the upper and lower hemispheres. As a result, the swivel shell 190 is free to tilt or rotate through a range of angles but is constrained to not move along the longitudinal axis of the implant abutment base 81. This curvature profile 96 of the swivel shell 190 can also provide greater surface contact area to tailor frictional properties of the swivel shell 190 on the ball 82.

[0130] Controlling the slip torque of the swivel shell 190 on the ball 82 independently of any locking screw' provides several benefits in using the multi-unit abutment. The threshold force for movement, or minimum slip torque, of the swivel shell 190 on the ball 82 can be predetermined in the design and manufacturing of the SA-MUA (assembly) 100. Slip torquesin the range of 1 to 10 N-cm provide consistent holding of the relative position of the swivel shell 190 to the ball 82 during further assembly and processing steps. These steps may include helping to seal the interface of the ball 82 and the shell 190 at its distal end 190D of the shell to help avoid bacterial contamination during installation into a patient, individually aligning a plurality of swivels 190 in ajaw 70 to engage a plurality of Ti bases 5 in a fixed arrangement in a prosthesis 68, holding swivel shells 190 in position for lift-off processing as detailed in referenced US Patent 11.311.354, and engaging and torquing the prosthetic screw 6 without holding the swivel 190. This inherent swivel shell 190 orientation holding ability (retention force) coming entirely / only from the forces from the swivel shell 190, e.g., the frictional fit / interference fit of the swivel shell 190 gripping the ball 82 above and below its equator are thus seen to assist not only in the assembly step of adding the prosthetic screw 6 (or temporary screw from US Patent 1 1,311,354 for lift-off processing) and Ti base 5, but also provide predictable slip torques for other process steps. The prosthetic screw 6 can be torqued to a higher desired permanent fixing value after final alignment with the coping without holding the swivel shell 190 facilitating ease of final assembly.

[0131] The swivel shell 190 can be a single-piece / one-piece metal swivel shell body and can be used alone with the ball 82 without requiring a lock screw as in conventional devices. The compressive forces necessary to provide deformation to capture the ball by the smaller final distal aperture wall 91 W may be applied with any of the techniques known in metal working. The aperture reduction through inelastic deformation may be done with a cold, w arm or hot metal working and / or forging process. Cold (metal) working is preferred due to better mechanical tolerance control and increased tensile strength through work hardening of the swivel shell 190 in the vicinity of the deformation. Cold working may also be beneficial in maintaining the exterior surface profile of the swivel shell 190 that interfaces with the interior of the coping 97 such as guiding surface 94 and seat 122. The mechanical properties of the ball portion 82 may also be selected to make it suitable for use as a backing support in the forging process.

[0132] An advantage with this approach is that the frictional clamping characteristics of the swivel shell 190 and ball portion 82 can be controlled in the process of manufacturing the multi-unit abutment assembly without any dependence on a locking screw. The threshold force magnitude in this swiveling constrained state required to change the relative angle of the assembly and the initial linear configuration for installation can be provided by the OEM or supplier independently of any dental practitioner’s on-site effort. In addition, the proximal and distal contact surfaces at 96P and 96D along and against ball curvature 89 shown inFIGS. 9 and 10 will help prevent the introduction of bacteria or other pathogens into the interior of the assembly during installation. By using the ball portion 82 as a backing support in this manner, spherical ring contact surfaces are formed at both the proximal and distal portions of the swivel shell 190 separated by its equator.

[0133] A preferred cold metal working process for forming the reduced aperture at 91 W is rotary’ swaging. For assembling multi-unit abutment 100. rotary swaging may be done by holding the abutment base 81 while rotating the swivel shell 190 with longitudinal axes aligned and forcing a tool against the distal end wall 90W of the swivel shell 190 at point 98 to sequentially move material near distal end 190D towards the axis of rotation to reform distal end wall 90W into distal end wall 91W. However, other metal forming processes, preferably cold working processes, may be used in deformation area as long as the process can consistently generate the desired shape / deformation and retain minimum wall thickness Tm without inducing material weakness. Although process specifics will depend upon material characteristics and specific geometries, several process parameters have been determined to be significant on the performance of rotary swaging of the swivel shell. Testing has shown that applying an axial pre-load force Fp (FIG. 9) to push the spherical surface 89 of ball 82 against the swivel shell 190 along the spherical interface 96 identified in FIG. 9 before deforming the wall 90W (FIG. 9) to create wall 91W to effectively change the shape of the initial aperture 193 (FIG. 9) to the final aperture shape 193 (FIG. 10) is useful in providing consistent fixing of the swivel shell 190 to the ball 82. This axial pre-load force Fp may range from around 4 to H O N, which is smaller than the maximum forces that might exceed 300 N in clenching teeth. Relative rotary’ motion between the swivel shell 190 and ball during the rotary swaging process may be used to polish contact surfaces. The swaging tool will make contact at point 98 with the swivel shell near distal end 190D and push against the distal end wall 90W to create distal end wall 91 W using a force F directed towards the longitudinal axis. As illustrated in FIG. 10, the swaging tool path and force F is not directed strictly perpendicular to the axis of rotation. It includes an axial component (that is, in a direction angled more towards the center of the ball) that may be used to increase the radial clamping force of the swivel shell 190 to the ball 82. Although the inelastic deformation of the w all 90W to form reduced aperture wall 91W is the predominate deformation, some elastic deformation directed radially at the spherical contact surfaces may contribute to the force for friction to resist relative angular movement. Depending upon the forces applied and tool design and swivel shell 190 geometry, there may be material displacement that causes a reduction of wall thickness of 90W from its original wall thickness T in FIG. 9 to thicknessTm of wall 91 W as shown in FIG. 10 accompanied with a slight elongation from material displacement.

[0134] Although FIG. 10 shows the swivel shell 190 being held on the ball 82 with contact above and below' the equator (eq) to hold the ball 82 at any angle w ithin the range of relative motion, the requirements on the extent of contact are asymmetrical under use in a patient. This asymmetry results in part from the large directional differences in forces applied by muscles in a jaw. While teeth can be clenched to provide forces in the range of 300 to 350 N pushing the swivel shell 190 down on the ball 82, the maximum separating forces that can be used to separate teeth stuck together, for example, wdth taffy to tty and pull the swivel shell 190 up off the ball 82 are considerably less in magnitude and exposure frequency. In the cross-sectional illustration of FIG. 12. the strength in the downward direction is more critical in use of the multi -unit abutment 100 over time than the upper direction. Resistance to movement of the swivel shell 190 w ill depend upon the surface area interfacing with the ball portion 82 mainly on the proximal surface. For proximally directed forces, the extent of the inelastic deformation that is done by moving the distal end 190D of the swivel shell 190 tow ards the axis and the thickness Tm of the distal wall 91W (FIG. 10) w ill determine the pull-out resistance for forces in the proximal direction. These characteristic distances will also influence the static torque values to allow positioning of the sw ivel shell and the ability to torque the prosthetic screw 6 without holding the swivel shell 190.

[0135] Consider the swivel shell 190 contact with the ball 82 in the enlarged view of FIG. 9. Due to the applied force in the axial proximal direction, the ball 82 will make contact with the internal curvature 96 of the swivel shell 190. The most proximal point of contact 96P w ill necessarily be located above the equator “eq” and at a radial distance R1 from the longitudinal axis of the abutment base 81. In FIG. 9, this contact point 96P is associated w ith the threading 8 for the prosthetic screw 6. From this point, the surface contact extends radially outw ard and downw ard tow ards the equator eq until it reaches a maximum outer radial distance of R2 at point 96E. For ideal parts, R2 is equal to the radius RB of the ball portion 82. Due to tolerancing of parts to ensure that the ball 82 can be slipped inside the swivel shell 190. R2 may be slightly less than RB for a particular design and manufacturing process precision capability. A difference of a few percent in these dimensions is not critical for the present discussion. The difference in radial distance R2 and Rl, or X, influences the mechanical strength of the assembly of the swivel shell 190 and ball 82 resisting forces in the distal direction. It also determines the surface contact area in the upper hemisphere which influences the static torque resisting swivel movement. The threading size for the prostheticscrew 6 and the shape of the Ti base 5 seating limit how large X can be. There are design tradeoffs in the capability of the swivel shell 190 alone to resist downward forces the overall height of the abutment 100 and the mating characteristics of the Ti base 5 along surface 94. A minimum X distance of about 0.04 mm has been found to be sufficient to handle the compressive forces directed distally with titanium parts. For the configuration illustrated in FIG. 10, X is about 0.5mm for standard size systems. Multi-unit abutments sized to be compatible with widely used Ti bases with the basic design illustrated in FIGS. 10 and 12 shown have a surface contact area of the ball to the swivel shell above the equator of about 6. 1 mm2.

[0136] In some embodiments, the contact surface area of the ball 82 to swivel shell 190 above the equator can be in a range of about 3 mm2to about 6 mm2. In some embodiments, this can be in a range of about 4 mm2to about 6 mm2.

[0137] The inelastic deformation of the distal portion of the swivel shell 190 provides resistance to separation of the swivel shell 190 from the ball 82 under proximally directed applied forces, seals the swivel shell 190 to the ball 98 at reduced aperture wall 91W and influences the slip torque resisting swivel movement. As shown in FIG. 10, the distal wall 91W of the swivel shell near distal end 190D after deformation contacts the ball over a distance along the ball surface profile terminating at the most distal point of contact 96D. This most distal point of contact 96D determines a radial distance from the longitudinal axis of R3. The difference between R3 and RB is designated XI. This dimension XI and the minimum wall thickness Tm of wall 91 W are important parameters in the functioning of the swivel 190. This distance XI with a particular material helps determine the uniformity and reliability of the swiveling, and holding characteristics of the shell during processing both in allowing relative motion to align with the prosthesis Ti bases 5 when desired, but not moving when torquing the prosthetic screw 6. Maintaining a minimum shell thickness Tm (FIG. 10) in the inelastic deformation region after the rotary swaging process is also an important consideration for maintaining consistent slip torque characteristics. In the case of titanium, a representative minimum thickness Tm of the distal wall 91 W of about 0. 1 millimeters (mm) is sufficient but starting with an initial w all thickness T at distal wall segment 90W (FIG. 9) of about 0.25 mm and reducing by less than about 5% to a thickness Tm as shown for distal w all segment 91 W in FIG. 10 as a result of the deformation process in the deformation region has yielded consistent results. Thus, an example minimum wall thickness Tm can be in a range of about 0. 1 mm to about 0.25mm, including 0.2 mm, 0. 3 mm. 0.4 mm, 0. 5 mm, 0. 6 mm, 0. 7 mm, 0.8 mm, 0.9 mm, 0.10 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm,0. 16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.20 mm, 0.21 mm, 0.22 mm, 0.23 mm, 0.24 mm and 0.25 mm. Other minimum wall thicknesses may be appropriate depending on the metal or metal alloy used. Although work hardening from cold metal working is often seen as a negative result that may be alleviated by annealing, that is not the case for the omnidirectional multi-unit abutments based on prototy pe testing. The additional tensile strength benefit does not appear to come with any negative consequences when a minimum thickness of 91 W is maintained in the inelastic deformation region. XI and the wall thickness Tm in the deformation region also influence the sealing of the reduced aperture of 91W at 190D to help prevent bacterial contamination ingress. These two parameters also determine the force necessary to pull the ball 82 out of the swivel shell 190. There are less constraints on these dimensions, mostly associated with the range of tilting of the swivel 190 without interference with the neck 95 of the abutment base 81. A distance XI of about 0. 13 mm provides consistent performance in titanium parts. The axial force required to separate the ball 82 from the swivel shell 190 by reversing the inelastic deformation from rotary swaging in actual parts has been measured to be in a range from 400 to 650 N, which is much higher than needed.

[0138] Representative prosthetic screw sizes include ml.4x0.3 threads, ml.6x0.35, UNF 1- 72, etc. Drive feature 60 may be a socket accommodating common dental drivers including Torx T5 or T6, 0.035"’ to 0.050"’ hex or square drivers, or similarly sized straight and star drivers with different numbers of lobes and geometries with an approximately 3.25 mm diameter ball. The tightening of the abutment base 81 to the implant may proceed until the desired seating pressure at the abutment seat 21 is obtained. A representative torque value is about 30 N-cm, although the value will depend upon the implant system employed and maybe higher or lower than this. For immediate loading of a prosthesis, the torque value should be less than the torque value used to install the implant 16 into the jawbone.

[0139] Sample parts demonstrate excellent sealing in the vicinity of wall 91W on FIG. 10 with anti-swivel threshold torques of several N-cm.

[0140] FIG. 11 show s tool 17 extending through the prosthetic screw threading 8 of the swivel shell 190 to drive the multi-unit abutment 190 into the implant 16. Note that the drive feature 60 of the ball illustrated has a width that is less than the minor diameter of prosthetic screyv matching threading 8, yvhich alloyvs a tool to be inserted through the threading 8 to engage the drive feature when longitudinal axes are aligned.

[0141] FIG. 12 shows the mounting of the coping 5 with prosthetic screw 6. Note that the distal end of the prosthetic screw 6 does not have sufficient length to contact the ball portion82 when fully engaged to hold the Ti base 5 into position. Torquing the prosthetic screw provides a seating force of the Ti base 5 on the swivel shell 190 but does not restrict the motion of the swivel around the ball 82. Fabricated parts verify that tool 17 is the only tool necessary to torque the prosthetic screw 6. Of course, an access hole through the prosthesis for the prosthetic screw 6 and tool 17 must be provided common with standard screw attached prosthesis processes.

[0142] Reference was made to the Goodacre et al. paper in the background section above about how trial and error alignment problems could make repairing an implant abutment assembly more difficult than the initial installation. As previously mentioned, Hess et al. proposed a process to overcome the difficulty in replacing one angulated multi-unit abutment of a system at the proper orientation. The process proposed in that paper includes fabricating a specialized tool using a definitive cast with abutment analogs that attaches to an adjacent abutment. One significant advantage of the current inventive concepts is that this orientation problem in replacing a damaged angulated multi-unit abutment to match a group of copings in a prosthesis is completely avoided.

[0143] FIGS. 13A-13D illustrates a sequence of steps showing how a pair of embedded Ti bases 5 in a prosthesis 68 can direct the self-aligning multi-unit abutments 100 during the prosthesis attachment process. These figures are cross-sectional views to show the changes in orientation of the swivel shell in response to contact with the embedded Ti bases. In FIG. 13 A, a prosthesis 68 with a pair of embedded Ti bases 5 is shown separated from a pair of target self-aligning multi-unit abutments 100. The longitudinal axes of the pair of Ti bases 5 lie in the plane of the figure. Similarly, the longitudinal axes of the pair of swivel shells 190 also he in the same plane and converge at a point outside the illustration. The angles are near the limit of the tilt range of the swivel shell 190 on the ball 82. Some initial alignment may be needed to have the proximal ends of the swivel shells 190 positioned where they can enter the distal ends of the embedded Ti bases 5 as shown. This orientation can be accomplished by a dental professional simply by moving the swivel shells with the fingers or a tool. The orientation will be maintained when the fingers are removed. This alignment is not critical.

[0144] In FIG. I3B, the longitudinal axes of the swivel shells 190 of the present embodiment have been directed tow ard the vertical direction by overcoming the frictional torque threshold provided entirely by the swivel interference fit of the swivel 190 with the ball 82 and as a result of downward motion of the prosthesis 68.

[0145] As the dental professional applies a downward force on the prosthesis 68. the conical surfaces inside the copings will apply a sideways force on the swivel shells along surface 94causing them to move towards the converging longitudinal axes of the Ti bases as shown in FIG. 13C. Here contact is made along cone profile 94 until contact is also made with one point of the seating surfaces 122. Further pressure will align the swivel shells 190 with the embedded Ti bases 5 as seen in FIG. 13D. When prosthetic screws 6 are inserted and torqued to the specified torque, the swivel shells 190 will be firmly held in final alignment.

[0146] In this sequence, there is no need for the extensive trial-and-error fittings of Goodacre et al. or the construction of any alignment jig as detailed by Hess et al. for replacing a fixed angular multi-unit abutment to an existing prosthesis. The sequence of steps shown is reversible, so it is possible to remove the prosthetic screws 6 after mounting subsequent to FIG. 13D and then pull the prosthesis 68 up and away from the self-aligning multi-unit abutments 190 to return to the separated configuration of FIG. 13 A. After removing the prosthesis completely, it is apparent that either of the self-aligning multi -unit abutments 100 shown could be removed from its implant 16, and a new self-aligning multi -unit abutment 100 attached to the implant 16. By simply redirecting the orientation of the swivel shell 190 as shown in FIG. 13 A, the prosthesis can be reattached by repeating the sequence of FIGS. 13B-13D. The fixed implant position provides the reference for the replacement multi-unit abutment sufficient to have the Ti base 5 realign the replacement multi-unit abutment angle.

[0147] The sequence above demonstrates the accommodation of misaligned components. It is instructive in show ing how replacement of broken elements can be accomplished with the inventive concepts disclosed. Another benefit from this angle adaptability of the self- adjusting multi-unit abutment during processing over fixed angle abutments is the ease of removing an impression tray from misaligned implant abutments. As discussed in the Buzayan et al. and Hanif et al. references, improved passive fit will reduce delayed mechanical failures of parts in the overall prosthesis superstructure by reducing static loads and strains, thereby reducing the need for replacement in the first place. This sequence shows the gross movement possible during installation. After the prosthetic screws are torqued to pull the swivel shells in alignment with the coping, smaller movements of the swivel shells is possible in response to movement due to osseointegration of the implants or changes in mechanical properties of the non-biological elements. Visual examination of FIG. 13D shows that the assembly is somewhat constrained already with two self-aligning multiunit abutments; as the number increases, positive positional fixing of the prosthesis is provided. Since natural teeth may move an order of magnitude more than the passive fit tolerance proposals, small tweaks during installation or over time for reducing mechanical stress and strain are not expected to have any practical impact on occlusion. Differentprosthetic screw tightening sequences may be used for finding the best fit analogous to other multiple threading patterns common in machinery maintenance.

[0148] FIG. 14 includes a resilient member 191 positioned between the swivel shell 190 and the proximal end of the ball 82. Including a resilient member 191 can be used to alter anti swivel forces or provide additional sealing. The resilient member 191 changes the frictional force of the swivel shell 190 against the ball 82 and may help pull the distal end of the swivel 190 towards the prosthetic screw for sealing particularly when a different slip torque is desired in a particular application. Modifying the motion threshold may be appropriate for different prostheses construction and mechanical strain properties. The resilient member 191 can be one or a combination of a hemispherical ring spring washer, elastically deformably hydrogel, polymer or copolymer, dome washer, Belleville washer and the like.

[0149] Referring to FIGS. 15-19, as an alternative to the screw attachment of the prosthesis, many of the features above that are not specific to prosthetic screws and screw attached copings may be adapted. FIG. 15 is an exploded view of a self-aligning omni-directional multi-unit abutment system 180 that incorporates snap-on coupling of a coping or Ti base embedded in a prosthesis. The specific differences will be described for this modification.

[0150] One embodiment of a snap-on self-aligning omni-directional abutment comprises an abutment base 81 as previously described, a swivel shell 83 for snap attachment, a retention liner 106, and coping in the form of a cap 105. The swivel shell 83 is modified to provide the snap connection, but its connection to the ball portion 82 of the abutment base is the same as previously described. That is, the ball 82 is captured by inelastically deforming the distal portion of the swivel shell 83 as described above for swivel shell 190. The exterior profile of the swivel shell 83 is adapted to provide a snap fit when cap 105 and retention liner 106 are forced down onto the proximal side of the multi-unit abutment. Without a prosthetic screw, the previous threading 8 is not required or needed. However, an aperture 108 sized to allow drive tool 17 to engage the implant base drive feature 60 is needed in the proximal end of the swivel shell 83. The cap 105 and retention insert 106 may be considered to provide the same orientation and attachment functionality as the copings 5 and prosthetic screws 6 described above. Cap 105 is generally metallic but can be made from a wide array of engineering materials used in dentistry. Although a cap or swivel shell with integral snap capability (not shown) may be used as an alternative to the two-piece system shown, commercially available snap abutment systems generally package and provide a single metal cap with a variety of different elastomeric retention inserts for processing, and temporary or semi-permanent attachment. In general, lower retention inserts are selected when a prosthesis is being snapatached to multiple abutments, particularly if the axes of the abutments are not all parallel. Since this disclosure provides a way to provide flexible orientation of multi-unit abutments, a smaller range of retention insert forces may be used in an individual patient. The cap 105 and retention insert 106 do not include an aperture since no tool is needed to extend through these elements. These will not be in place when drive feature 60 is used.

[0151] FIG. 19 provides a cross-sectional view of these four elements in a linear assembly. As was the case with the first embodiment, the distal end wall of swivel shell 83 may be inelastically deformed using the ball portion 82 as a backing to create a reduced aperture at wall segment 192. The swivel shell and ball interaction when the coping atachment is prosthetic screw torquing can be applied when the means of coping atachment is a snap fit, a shape memory material shift or other mechanical attachment means known in dentistry. Since the one-piece swivel deformation processing and benefits are not dependent upon what means are used to atach the coping to the implant abutment, it is not necessary to repeat those shared details here. As in the previous embodiment, rotary swaging is a preferred method to produce radially inward forces for frictional holding of the swivel shell 83 on the ball portion 82. FIG. 19 shows intimate contact along surface 196 of the one-piece swivel shell 83 with the ball 82 both axially above and extending below the doted line of the equator after forming. Comparison to earlier cross-section in FIG. 11 of the implant base 81 and distal portion of the swivel shell 83 with distal portion of swivel shell 190 shows an identical profile of the contact surfaces of these mating parts from the lower wall portion to a point well above the equator of the ball portion 82. The characteristics and benefits of rotary swaging of this one-piece swivel shell configuration follow directly from the previous discussion. As a result, all of the options for cold working to reduce the lower aperture after ball insertion, swiveling action, slip torque performance, radial force components above and below the equator, and compressive washer option 191 apply here and will not be repeated. It is evident that the cross-section in FIG. 19 represents a swivel shell 83 that only has freedom to rotate and tilt due to the cold forming processing, preferentially from rotary swaging, of a one-piece swivel. Since there is no prosthetic screw threading, the surface contact area between the ball and swivel spherical surfaces is potentially larger with the snap fit if desired to increase slip torque thresholds through this parameter. The exterior surface of the swivel shell 83 has been modified to provide a snap interface instead of the conical interface / connection surface 94 in the first embodiment.

[0152] Although the retention insert 106 is shown as lining the distal surface of the cap 105. it could also be of the form of a flat or domed profile ring or even an O-ring (not illustrated).Particularly in ring form, it may be desirable to attach the ring to the swivel shell 83 before snapping on the cap 105. Unlike previous embodiments, the proximal surface of swivel shell 83 has a larger diameter than the proximal surface of the swivel shell 190. A surface profile 187 on the swivel shell 83 with a protuberance similar to an indentation profile 188 on the cap 105 is not required but may be useful in providing a secure snap retention action. An O- ring or other shape as an alternative to the retention member 106 following the profile of the cap 105 is an obvious modification of the system shown. Regardless of the actual shape, it is desirable to have the retention member provide a seal that prevents bacteria from passing between the cap 105 and swivel shell 83 to enter the aperture 108. Two-piece swivel shells or two-piece ball base assemblies are also possible with snap systems, but are not preferred.

[0153] As in previous embodiments, implant drive tool 17 may be inserted through the aperture 108 in the top of the swivel shell 83 to engage the drive feature 60 of the base 81 and tighten it to a desired torque in an implant 16. After repositioning to a desired angle in alignment with a cap 105 already embedded in a prosthesis, potentially through a lift-off process, retention liner 106 would typically be attached to the cap 105 in the prosthesis. Downward pressure on the prosthesis causes the cap 105 and retention liner 106 to compress and relax partially to hold elements together as shown in FIG. 20.

[0154] Generally, lower force retentive inserts with wider angular mismatch capability' must be used to compensate for a greater angular divergence in snap-on abutment axes. Any improvement in relative parallelism of multiple snap-on abutments is a desirable result since forces on retentive inserts will be more uniform. This redistribution of forces can make the processes of snapping the prosthesis on and off abutments easier and reduce stress on both the prosthesis and implants.

[0155] A variation of the process described above for screw-attached prostheses can also be used with the snap-on system 180.

[0156] As noted, deformation of the retention insert 106 helps take up some of the angular misalignment between multiple multi-unit abutments 180 associated with a single prosthesis 68. Even if all multi-unit abutments are perfectly aligned initially, over time the prosthesis or the patient’s jaw may change shape decreasing the passive fit. An overly rigid system does not mimic the movement of natural teeth, so with this embodiment, forces can be redistributed in the snap system without dental professional action to maintain or improve passive fit by allowing unbalanced forces in the retention inserts to move the swivel shells to equilibrate the stresses to provide a more passive fit. If the prosthesis or jaw geometry changes over time, the swivel shells would readjust orientation to redistribute forces to obtaina more passive fit in this new geometry'. The force required to reorient the swivel shells for self-adjustment would depend upon geometries and mechanical properties of the parts.

[0157] The discussion above described how the swivel shells of different embodiments will hold themselves in a particular orientation until an applied force is applied to shift them to another angular orientation. While this redirection can be done with fingers, considering the small size of the assemblies it may be useful to have a tool to move the swivels in a patient’s mouth more easily and also to have an indicator of what angle they are set at. FIG. 21 shows an orientation post 300 for prosthetic screw attachment embodiments. One-piece orientation post 300 may be economically fabricated from plasticsuch as thermoplastics or other polymers but could be made of any material sufficiently stiff to be useful. It comprises a proximal shaft portion 306, threaded portion 301 to engage the threading 8 of the swivel shell 190 used by the prosthetic screw 6, distal seating surface 322, and interior profile 394 complementary' to profile 94. The orientation post is rotated to engage threading 301 and torqued until seating is achieved at surface 322. This aligns the linear axis of the orientation post with the linear axis of the swivel shell 190 to provide an axial indicator. The length of the shaft provides mechanical leverage to overcome the slip torque threshold. The axial indicator function is useful in aligning multiple swivels in some processing functions. Of course, a snap-on version providing similar functionality' with the snap-on swivel shell 83 could provide similar benefits by simply replacing the attachment threads and seating surface geometries in FIG. 21 with their counterparts from FIG. 19. Other tools for moving swivel shells can be as simple as a rod with an aperture perpendicular to its axis to slip over a swivel shell, but do not have the dual benefit of visual indication and mechanical advantage.

[0158] Various embodiments have been described to illustrate the disclosed inventive concepts, not to limit the invention. Whether prosthetic screws or a snap system securely holds the prosthesis to the multi-unit abutments, the orientation of the swivel shells of the multi-unit abutments are not individually fixed in position. They may be positioned as desired for prosthesis attachment or removal. During initial installation and during the life of the dental restoration, the swivel shells are free to respond to unbalanced forces. The prosthesis generally constrains the initial orientation of the set of omni-directional multi-unit abutments, but the swivel shells may reorient to maintain the most passive fit possible with changes over time.

[0159] It is preferred that the omnidirectional multi-unit abutment 100 embodiments above be adapted to be compatible with Ti bases 5 and threaded implants 16 that have already been qualified and commercially successful. The threading and seating to widely availableimplants improves the inventory equation since the same implants may be used with conventional straight abutments as well as the embodiments above in the same patient. While less critical, the compatibility with widely available screw-attached Ti bases 5 is also seen as an advantage However, inventive features of the described embodiments can be integrated into or adapted to work with newly designed implants that adopt inventive concepts for passive fit improvement or installation efficiency and repair described above. As described above for the snap retention system, these inventive concepts can also be adapted to work with prostheses that are not attached with screws. These adaptations are not excluded and are considered to be disclosed herein and within the scope of claims that may be broadly interpreted to apply to them. US Patent 11,311,354 includes different approaches for aligning Ti bases with abutments for incorporation into a prosthesis using a temporary fastener in a lift-off process. The basic design of the temporary fasteners illustrated in that co-owned patent can be employed with the omnidirectional multi-unit abutments and Ti bases described above.

Claims

THAT WHICH IS CLAIMED:

1. A system for alignment and attachment of a dental prosthesis to an implant, the system comprising: an abutment base having a longitudinal axis, the abutment base comprising a proximal end portion comprising a ball with an abutment base drive interface and a distal end comprising screw threads for attachment to the implant, wherein the ball comprises an equator; and a swivel shell comprising a proximal end portion and an opposing distal end portion, an inner surface, an outer surface and a longitudinal axis, wherein the swivel shell further comprises an open internal channel extending along the longitudinal axis between the proximal end portion and the distal end portion, wherein the swivel shell has an interference fit against the ball and contacts the ball at or above the equator of the ball and below' the equator of the ball when the longitudinal axis of the abutment base is aligned with the longitudinal axis of the sw ivel shell w hereby the swivel shell is able to tilt and rotate in response to forces applied to the swivel shell above a defined force, and wherein the swivel shell is configured to press against the ball with sufficient force to retain a desired tilt angle.

2. The system of Claim 1, wherein the swivel shell has a deformable wall at a distal end portion thereof so that the deformable wall is configured to have a first configuration for assembly to the ball that deforms to a second configuration to capture the ball in the swivel shell wfiereby the sw ivel shell contacts the ball above and below the equator of the ball when the longitudinal axis of the abutment base is aligned w ith the longitudinal axis of the swivel shell.

3. The system of Claim 2, wherein the swivel shell has a single piece monolithic metal body providing all ball contact surfaces, and wherein, in the second configuration, the swivel shell has a minimum wall thickness at the distal end portion that is in a range of about 0.1 mm to about 0.25 mm.

4. The system of Claim 1, further comprising a dental coping, wherein the dental coping is sized and configured to on an upper exterior portion of the swivel shell, wherein a forceabove a defined value and applied in a distal direction to the dental prosthesis containing the dental coping results in a force applied to an interface with the swivel shell sufficient to change an orientation of the swivel shell relative to the ball.

5. The system of Claim 1, wherein the swivel shell is configured to tilt and / or rotate relative to the ball when an applied torque of above 1 N-cm is applied thereto.

6. The system of Claim 1, wherein the inner surface of the swivel shell defines a contact surface with the ball above the equator when the longitudinal axes are aligned that is in a range of about 3 mm2and about 6 mm2, optionally in a range of about 4 mm2and about 6 mm 2.

7. The system of Claim 1, the system further comprising a prosthetic screw, wherein the open channel of the swivel shell comprises threads sized and configured to engage the prosthetic screw, and wherein the prosthetic screw threadably engages the threads of the open channel of the swivel shell.

8. The system of Claim 1, wherein the system further comprises a snap-on cap that is sized and configured to engage the proximal end portion of the swivel shell to attach the dental prosthesis to the abutment base, and wherein the snap on cap is affixed to a Ti base coupled to an internal side of the dental prosthesis.

9. The system of Claim 1, further comprising a snap-on cap that is sized and configured to engage the proximal end portion of the swivel shell, wherein at least some of the proximal end portion of the swivel shell resides inside the snap-on cap.

10. The system of Claim 1, wherein the swivel shell is configured to be used without a lock screw to couple to the ball, wherein the prosthetic screw is rotatable in the swivel shell to tighten to a prescribed torque and cooperates with the swivel shell whereby the swivel shellalone provides a holding force against the ball to be at a desired angle relative to the ball, and wherein the swivel shell holds the ball with sufficient force to allow the prosthetic screw to be tightened in the swivel shell when the abutment base is attached to the implant.

11. The system of Claim 2, wherein the distal end portion of the swivel shell is rotary swaged to capture the ball while applying an axial load to the swivel shell with the ball held in the swivel shell to form the second configuration whereby the swivel shell captures the ball by deforming the distal end of the swivel shell.

12. The system of Claim 1, further comprising a Ti base, wherein the Ti base has an aperture on the proximal end that is larger than a shaft of a prosthetic screw and smaller than a head of the prosthetic screw7and a distal end that is shaped to reside against a seating surface in the outer surface of the swivel shell.

13. The system of Claim 1, further comprising an orientation tool comprising an orientation post that extends into the open channel of the swivel shell to engage the swivel shell using threads of the sw ivel shell in the open channel that are configured to threadably engage a prosthetic screw and apply a force / torque sufficient to slidably move the sw ivel shell into a selected orientation with the ball.

14. The system of Claim 1, further comprising a resilient member residing between the proximal end of the ball and the distal end portion of the swivel shell thereby facilitating slip resistance and / or maintain a seal between the ball and swivel shell.

15. The system of Claim 1, wherein the swivel shell and ball are sized and configured to provide attachment to the implant and dental prosthesis without a lock screw.

16. The system of any of Claims 1-15, wherein the open channel of the swivel shell comprises threads sized and configured to directly engage a prosthetic screw or the open channel of the swivel shell is devoid of threads.

17. The system of any of Claims 1-15, wherein the swivel shell comprises a single piece monolithic metal body that provides a shaped inner surface extending about an internal cavity that holds and captures the ball and provides a contact surface against the ball above and below the equator of the ball when the longitudinal axis of the abutment base is aligned with the longitudinal axis of the swivel shell.

18. The system of any of Claims 1-15, wherein the swivel shell and ball are configured to slidably cooperate to allow a passive internal in situ change in alignment between the implant and / or the dental prosthesis post-installation without external intentional manipulation of the swivel shell.

19. A dental system for alignment and attachment of a full arch dental prosthesis to a plurality of dental implants, the system comprising: a plurality of abutment bases, each abutment base having a longitudinal axis, the abutment base comprising a proximal end portion comprising a ball with an abutment base drive interface and a distal end comprising screw threads for attachment to the implant, wherein the ball comprises an equator; and a plurality of swivel shells, each swivel shell comprising a proximal end portion and an opposing distal end portion, an inner surface, an outer surface and a longitudinal axis. wherein each swivel shell further comprises an open channel extending along the longitudinal axis between the proximal end portion and the distal end portion, wherein the swivel shell comprises a single piece monolithic metal body that provides a shaped inner surface extending about an internal cavity that holds and captures the ball and provides a contact surface against the ball above and below the equator of the ball when the longitudinal axis of the abutment base is aligned with the longitudinal axis of the swivel shell, and wherein at least some of the swivel shells cooperate to rotate relative to each other and relative to coupled abutment bases target implants define proper alignment at installation.

20. The system of Claim 19, wherein the system is configured to allow passive in situ change in alignment between the implants and / or the full arch dental prosthesis post-installation without direct external intentional manipulation of the swivel shell.

21. The system of Claims 19-20. wherein the swivel shells have deformable second end portions that deform to capture the ball to form an assembly to the corresponding swivel shell and provide a factory preset orientation retention force to hold the swivel shell in a desired orientation using only the swivel shell and ball.

22. A system for alignment and attachment of a dental prosthesis to a dental implant, comprising: an abutment base having a longitudinal axis, the abutment base comprising a proximal end portion comprising a ball with an abutment base drive interface and a distal end comprising screw threads for attachment to the implant, wherein the ball comprises an equator; and a swivel shell comprising a proximal end portion and an opposing distal end portion, an inner surface, an outer surface and a longitudinal axis, wherein the swivel shell further comprises an open internal channel extending along the longitudinal axis between the proximal end portion and the distal end portion; and wherein the swivel shell is configured to capture the ball to prevent axial movement relative to the longitudinal axis of the abutment base and provide a desired tilt orientation in a range of about 0 degrees to about 30 degrees, and wherein, at assembly, the swivel shell captures the ball as a result of upper and lower hemisphere forces on the ball from contact with the ball above and below the equator of the ball when the longitudinal axis of the abutment base is aligned with the longitudinal axis of the swivel shell providing a frictional engagement therebetween w ereby a swivel shell minimum orientation retention force is factory7preset.

23. The system of Claim 22, wherein the swivel shell has a distal end w all segment that inelastically deforms to contact the ball thereat.

24. The system of Claim 23, wherein the distal end wall segment seals against the ball.

25. The system of any of Claims 22-24, wherein the swivel shell is a single piece monolithic body providing all surface contact with the ball whereby the swivel shell has an interference fit against the ball and contacts the ball at or above the equator of the ball and below the equator of the ball w hen the longitudinal axis of the abutment base is aligned with thelongitudinal axis of the swivel shell whereby the swivel shell is able to tilt and rotate in response to forces applied to the swivel shell above a defined force, and wherein the swivel shell is configured to press against the ball with sufficient force to retain a desired tilt angle.

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