HK1164097A - Dental impression cap with engagement feature - Google Patents

Description

Denture impression cap with engagement features

Technical Field

The present invention relates generally to the field of prosthetic tooth components and, more particularly, to components used in a process of taking an impression of a patient's mouth to record the precise location and orientation of the implantation site to enable precise manufacturing of prosthetic components. The components of the present invention include impression caps used in post impression methods and abutments, implants, isomorphs (analogies) and other prosthetic components designed to removably engage the impression caps.

Background

Prosthetic dental implants are widely used to replace dropped or damaged real teeth. Insertion of the implant can be accomplished in multiple steps. First, the implant is positioned within the patient's maxilla or mandible and allowed to recover for a period of time during which bonding of the material of the implant to the bone occurs. During this period, the therapeutic cap may be positioned over the implant. After the treatment period, the treatment cap may be removed and the abutment coupled to the implant. Once the abutment is fixed, an impression can be taken to accurately record the position and orientation of the implantation site and provide the information needed to manufacture the prosthetic component.

One method of taking an impression of the implantation site involves the use of an impression or conversion cap. The impression cap is placed over the abutment or implant. Impression material is applied to the site such that the impression material is squeezed around the impression cap and into the implantation site and then removed from the patient's mouth. When removed, the implant cap remains within the implant material, and thus this facilitates removable engagement of the impression cap with the abutment or implant during the impression making process. The impression material is used to form a mold of the implantation site for manufacturing the desired replacement part.

Disclosure of Invention

The present invention relates to impression caps or other dental crowns for removable engagement with, for example, abutments, implants and/or casts. Impression caps or other crowns are designed with engagement features, external alignment features, and internal alignment features to provide precise assembly of the cap onto the prosthetic part. In addition, the impression cap or other crown is designed not to extend below the gingival margin, compacting the outer surface and minimizing or eliminating interference with the soft tissue surrounding the implant.

More particularly, the present invention relates to impression caps or other dental crowns that include a partial circumferential rib or other engagement feature formed on a coronal portion of an interior surface of the cap to removably engage a groove formed in a corresponding surface of an abutment, implant, replica or other component and enable tactile confirmation that the cap is properly positioned on the component. The cap is optionally provided with an inner alignment surface corresponding to an alignment surface formed on the outer surface of the prosthetic tooth component, with an optional outer alignment feature that is externally visible and that tactilely assists in aligning the inner alignment surface of the cap with the component. The cap may also include one or more chamfered and/or cylindrical surfaces to aid in precise assembly of the cap on the component.

The dental crown according to the present invention may comprise: a body having a frustoconical outer surface, an inner recess, a closed coronal end, and an open apical (apical) end; a frustoconical inner surface disposed within the recess; and an engagement feature formed as a protrusion on the inner surface and extending at least partially circumferentially around the inner recess, wherein the engagement feature is positioned closer to a coronal end of the inner recess than to a root tip of the inner recess. The crown may further include a crown tapered surface and an apex tapered surface, wherein the crown and apex tapered surfaces form a crown edge and an apex edge, respectively, of the engagement feature. The crown and the apical tapered surfaces may have taper angles designed to achieve a snap fit of the engagement feature with the prosthetic tooth component.

Furthermore, a cylindrical engagement surface is optionally provided on the inner surface of the open root tip, wherein the cylindrical engagement surface engages a cylindrical surface portion of the prosthetic tooth component extending from below the gingival marginal tissue. One or more chamfer surfaces may optionally be provided on the coronal adjoining cylindrical engaging surface of the inner surface, wherein the chamfer surfaces are inclined at different angles with respect to the longitudinal axis of the crown and are arranged to receive inclined surface portions of the coronal adjoining cylindrical surface portions of the prosthetic tooth part. The crown may also include a coronal extension alignment structure positioned on the closed coronal end and/or a planar alignment surface extending longitudinally on the interior surface. If provided simultaneously, the planar alignment surface may be aligned with the coronal extension alignment structure.

A prosthetic assembly for use with a dental crown may include a prosthetic component including a groove for engaging an engagement feature within an inner recess of the dental crown to enable removable engagement of the impression cap with the prosthetic component. The groove or engagement feature of the prosthetic tooth component may also include a crown tapered surface and an apical tapered surface corresponding to the crown and apical tapered surfaces of the engagement feature on the crown.

If the alignment features are provided on a dental crown as described above, the prosthetic component may also include a flat outer surface portion that aligns with the flat alignment surface and the coronal extension alignment structure of the dental crown. The prosthetic part may also include a cylindrical and/or chamfered surface corresponding to an optional cylindrical and/or chamfered surface of the crown.

These and other features and advantages of the present invention will become more readily apparent to those skilled in the art from the following detailed description, wherein there is shown and described an illustrative embodiment of the invention, including the best mode contemplated for carrying out the invention. As will be realized, the invention is capable of modifications in various obvious aspects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

Drawings

Fig. 1 shows a cross-sectional view of an impression cap, an abutment and an implant according to the present invention.

Figure 2 illustrates a rotated view of a cross-sectional view of the impression cap, abutment and implant of figure 1.

Fig. 3 shows a radial cross-section of the impression cap taken along line a-a of fig. 2.

Fig. 4 is a detailed view of the engagement features of the impression cap of fig. 1 and 2 and the corresponding groove formed in the abutment.

Fig. 5 shows a radial cross-section of the impression cap taken along line B-B of fig. 2.

Figures 6 and 7 show external views of the impression coping of figures 1 and 2.

Fig. 8 is a three-dimensional perspective view of the impression coping of fig. 1 and 2.

Fig. 9 illustrates a cross-sectional view of an exemplary abutment that may be used with the impression cap of fig. 1-8.

Figure 10 illustrates a rotated view of a cross-sectional view of the abutment of figure 9.

Figure 11 is a detailed view of a groove formed in the abutment of figures 9 and 10.

Figure 12 is a top view of the abutment of figures 9-11.

Fig. 13 illustrates three exemplary abutments for use with the impression cap of fig. 1-8.

Figure 14 illustrates three exemplary implant/abutment assemblies for use with the impression coping of figures 1-8.

Figures 15 and 16 illustrate features of an alternative impression cap, abutment and implant according to the present invention.

Fig. 17 illustrates the use of the impression coping of fig. 15 and 16 with the same mold.

Detailed Description

The present invention will now be described with reference to the accompanying drawings. The drawings are intended to provide examples of implementations of the present invention and are not intended to limit the inventive concepts to the structures shown. The inventive engagement and alignment features described herein may be implemented with a variety of crown and denture components that will be apparent to those skilled in the art.

Referring to the drawings, figure 1 shows an impression coping 1 having a coronal end 2, a root tip end 3 and a longitudinal axis L. The impression cap 1 is positioned on an abutment 5, the abutment 5 being coupled to the implant 4.

The impression cap 1 forms an internal recess with a frustoconical shaped inner surface 6 which is closed at the surface 19 of the coronal end 2 of the cap 1 and open at the apical end 3 of the cap 1. The inner concave inner surface 6 of the cap 1 is generally frustoconical in shape, tapering inwardly from the root tip 3 to the coronal end 2 of the cap 1.

The outer surface 7 of the impression cap 1 may be generally frusto-conical in shape, tapering inwardly from the root tip 3 to the coronal end 2 of the cap 1. The cap 1 may be provided with a number of formations on its outer surface, for example to assist in locating the cap 1 on the abutment 5 and/or to facilitate insertion of the cap 1 into the impression material. Specifically, the cap 1 includes a coronal extending alignment structure 10, the structure 10 extending from a generally planar 11 surface 17 of the cap 1 to assist in aligning the cap 1 on the abutment 5. Additionally or alternatively, one or more projections, such as circumferential projections 11, may be provided extending radially from the outer surface of the cap 1. The coronal end 2 of the cap 1 may also have a shoulder 16. The inwardly tapering portion 18 may be provided at the apical base of the cap where the cap 1 surrounds the abutment 5.

The inner surface 6 of the impression cap 1 is provided with engagement features 12 comprising circumferential or partially circumferential ribs or other protrusions extending from the inner surface 6 towards the longitudinal axis L of the cap 1. The engagement features 12 are positioned to engage with corresponding partial circumferential recesses 20 formed in the inner surface of the abutment 5. The engagement feature 12 is positioned such that a distance D1 between the coronal surface 22 of the implant 4 (where the abutment emerges from the implant 4) and the engagement feature 12 is greater than a distance D2 between the engagement feature 12 and the coronal surface 92 of the abutment 5.

Near the root tip 3 of the cap 1, the inner surface 6 of the cap 1 may also include one or more chamfered surfaces (such as surfaces 13 and 14) and one or more longitudinally extending engagement surfaces, such as surface 15.

In the embodiment of fig. 1, the surface 13 is beveled away from the surface of the abutment 5 to create a space or gap between the inner surface 6 of the cap 1 and the outer surface of the abutment 5. As shown in fig. 1, the space or gap extends from an upper point 24 to a lower point 25. The coronal surface 22 of the implant 4 is contained within this space. The chamfered surface 13 is provided to facilitate insertion of the cap 1 onto the abutment 5 and the implant 4 by receiving the coronal surface 22 of the implant 4, the coronal surface 22 of the implant 4 extending beyond the outer surface of the abutment 5 in a radial direction.

The engagement surface 14 corresponds to an outwardly tapered frustoconical surface 1400 surface of the abutment 5 (see fig. 14). As shown in fig. 14, the surface 15 corresponds to a longitudinally extending cylindrical surface 1401 of the implant 4. Additional and/or alternative beveling and/or longitudinal surfaces may be provided on the inner surface 6 of the cap 1 if precise assembly of the cap 1 onto the implant 4, abutment 5 or other component may be required.

An empty space 23 may be formed inside the cap 1 between the coronal end 92 (see fig. 9-11) of the abutment 5 and the coronal inner surface 19 of the cap 1. The surface portion 21 of the inner surface 6 may abut an outer circumferential portion of the top surface 92 of the abutment 5.

Fig. 2 shows a view of the impression cap 1, the abutment 4 and the implant 5 of fig. 1 rotated 90 degrees about the longitudinal axis L of the cap 1. An alignment feature is provided on the inner surface 6 of the cap 1. In particular, a substantially flat inner surface portion 9 is provided, extending longitudinally and substantially parallel to the longitudinal axis L of the cap 1. The surface portion 9 is aligned with the extension 10 on the coronal end 2 of the cap 1 to assist in the alignment of the cap 1 on the abutment 5. At the root tip of the surface portion 9, a curved surface portion 8 (described below with reference to fig. 10) corresponding to the inner surface of the abutment 5 is provided.

Fig. 3 is a sectional view of the impression coping of fig. 2 along the line a-a. The cross-sectional view shows the circumferential projection 11, the engagement feature 12, the surface portion 21 abutting the top of the abutment 5, and the alignment surface portion 9.

Fig. 4 is a detailed view of the engagement features 12 formed on the inner surface 6 of the impression cap 1 and their alignment with the grooves 20 formed in the surface 400 of the abutment 5.

The engagement feature 12 may be designed to enable tactile confirmation that the impression cap 1 has been properly positioned on the abutment 5 (or other dental item). Tactile confirmation of proper positioning of the cap 1 can provide a snap-in feel, as the engagement feature 12 snaps into the recess 20. To achieve this snap-in feel when the engagement feature 12 engages the recess 20, the engagement feature 12 builds up potential energy before snapping into engagement with the recess. The engagement feature 12 then releases this energy in a rapid motion as it enters the recess 20. The recess 20 then hardstops movement of the engagement feature 12. This result produces a snap-in feel which enables tactile confirmation of the correct positioning of the cap 1 on the abutment 5.

The connection of the outer cone (here the impression coping 1) over the inner cone (here the abutment 5) necessitates a limitation of the damping effect of the cone-cone interference. When the engagement feature 12 on the cap 1 extends to the surface 400 of the abutment 5, it adds potential energy. When the engagement feature 12 reaches the recess 20, it snaps out into the recess 20. This quick release causes the cap 1 to move quickly in the apical direction onto the abutment 5. When the engagement feature 12 encounters the apex side of the depression 20, the engagement feature abruptly stops. This abrupt stop provides a snap-in feel that is created by the inertia of the inner surface 6 of the cap 1 slamming against the outer surface 400 of the abutment 5 and forming a hard stop (essentially, causing a micro-impact) causing noise and shock. To ensure that the result of this interaction can occur to produce the desired snap-fit feel (i.e., the cap 1 moves quickly and then stops abruptly when the engagement feature 12 engages the recess 20), a gap is provided between the frustoconical surface of the abutment 5 and the inner surface 6 of the cap 1 to prevent unwanted impact damping. To achieve this gap and to preserve proper assembly between the cap 1 and the abutment 5, the frustoconical coronal surface of the abutment 5 is slightly tapered on both sides (coronal and apical) of the recess 20. The cap 1 is provided with tapered surfaces 401 and 402 forming the coronal and apical edges, respectively, of the engagement feature 12. The root-tip and crown taper angles of the surfaces 403 and 404 of the edge recess 20 of the abutment 5 correspond to the corresponding taper angles of the surfaces 401 and 402 of the cap 1. The taper angles of the surfaces 401, 402, 403 and 404 may preferably be in the range of 1-2 degrees with reference to the inner surface 6 of the cap 1 or the outer surface 400 of the abutment 5, although any desired angle may be used. The root taper angle and crown taper angle may be substantially the same or may be different as desired to produce the desired snap feel.

In the illustrated embodiment, the engagement features 12 are provided as partial circumferential ribs which are manufactured as an integrally molded part of the impression cap 1. The engagement feature 12 extends around the perimeter of the inner surface 6 and does not extend across the alignment surface portion 9 of the inner surface 6. The engagement feature 12 is provided at a point on the inner surface 6 of the cap 1 such that the distance D1 is greater than the distance D2 (see fig. 1). When the impression cap 1 is assembled over the abutment 5 and pressed in the apical direction 3, the ribs engage the grooves 20 in the abutment 5 and secure the impression cap 1 against the top of the implant 4 at the surfaces 14 and 15. The cooperation of the ribs 12 with the grooves 20 may produce a tactile confirmation in the form of a snap, which indicates that the impression cap 1 is correctly positioned on the abutment 4 and the implant 5.

In alternative embodiments (not shown), the engagement features 12 may extend around the entire perimeter of the inner surface 6 of the cap 1, may extend only partially around the perimeter, or may be provided as a plurality of protrusions at different locations if desired to enable removable engagement of the cap 1 and the abutment 5. The engagement feature 12 may also be made of any desired material and may be made as a molded part of the cap 1 or as a separate component that is subsequently attached to the cap 1.

Referring to fig. 5, a sectional view taken along line B-B of fig. 2 shows the internal configuration of the impression cap 1, including the coronal inner surface 19, the surface portion 21, the engagement feature 12, the inner surface 6, the alignment surface portion 9, the surfaces 13, 15 and 14, and the outer protrusion 11.

Fig. 6 and 7 show external views of the impression coping 1, comprising the longitudinally extending portion 10, the top surface 17, and the protrusion 11.

Fig. 8 is a three-dimensional perspective view of the impression coping 1, including the surfaces 13, 14, and 15, the inner surface 6, the engagement feature 12, the alignment surface portion 9, and the curved surface portion 8.

The impression coping 1 can be made from acetal or any other desired material by conventional moulding or other manufacturing methods.

It is contemplated that therapeutic caps, fired crowns, and other types of braces may be provided with engagement features such as features 12 described herein to enable removable mating of the cap with temporary or permanent abutments, casts or duplications, and/or other prosthetic components.

Fig. 9 shows an abutment usable with the above-described impression cap 1. The abutment 5 includes means for coupling the abutment 5 to the implant 4 (e.g., as shown in fig. 1 and 2). For example, the abutment 5 may be provided with a screw thread that can be screwed into a thread receiving hole of the implant 4. Alternative coupling mechanisms may also be utilized.

In fig. 9, the portion Y of the abutment 5 comprises a threaded portion 91 for engagement with a screw thread (not shown) in the internal bore of the implant 4 and a substantially frustoconical portion extending from the point 90 towards the root tip of the threaded portion 91 and tapering inwardly towards the longitudinal axis L. Part Y is inserted into implant 4. The portion X of the abutment 5 is a generally frustoconical portion extending coronally from the point 90 and tapering inwardly toward the longitudinal axis L to a coronal end 92 of the abutment 5. When portion Y is inserted into implant 4, portion X extends out of implant 4 in the coronal direction.

In the embodiment of the present invention, the partial circumferential groove 20 is formed at a position above the center of the portion X in the surface of the abutment 5. The groove 20 extends around the perimeter of the abutment 5 and does not extend over the flat alignment surface portion 1010 of the abutment outer surface. The channel 20 is configured to receive the engagement feature 12 of the impression cap 1. The position of the groove 20 is such that the distance P (from the coronal end of the abutment to the groove 20) is less than the distance Q (from the groove to the point 90, when the abutment 5 is inserted into the implant 4, the coronal end of the implant 4 is located at the point 90). The channels 20 are formed for engagement with the engagement features 12 on the impression cap 1 as described above to enable removable mating of the cap 1 with the abutment 5 and the implant 4.

Figure 10 is an illustration of the abutment 5 of figure 9 having been rotated 90 degrees about the longitudinal axis L of the abutment 5. Fig. 10 shows a flat alignment surface portion 1010 and a curved surface portion 1000 formed on the abutment 5 to facilitate alignment of the abutment 5 and the impression cap 1 by aligning the flat surface 1010 of the abutment 5 with the flat alignment surface portion 9 of the cap 1 and aligning the full surface portion 1000 of the abutment 5 with the curved surface portion 8 of the cap 1 (as shown in fig. 2).

Fig. 11 is a detailed illustration of the groove 20 formed in the surface of the abutment 5.

Fig. 12 is an illustration of the coronal plane of the abutment 5, including the coronal end 92 of the abutment 5, the trough 20, the point 90, the flat surface portion 1010, and the curved surface portion 1000.

Fig. 13 shows three exemplary geometries of the abutment 5, all of which are designed to engage with the impression cap 1. Fig. 13(a) shows the abutment 5 having the X portion with a length of 7.0 mm. Fig. 13(b) shows the abutment 5 having the X portion of 5.5mm in length. Fig. 13(C) shows the abutment 5 having the X portion of 4.0mm in length. Other abutment lengths may be used if desired.

In each of the three embodiments shown in fig. 13, the groove 20 is positioned above the midpoint of the portion X of the abutment to engage with the engagement feature 12 of the impression cap 1 described above with reference to fig. 1 and 2.

Fig. 14 shows an exemplary assembly of an implant 4 and an abutment 5, which may be used with the impression coping 1. The abutment 5 extends coronally from the implant 4 from a point 90 to a coronal surface 92 of the abutment 5. The coronal surface 22 of the implant 4 is also shown. In addition, implant 4 includes an outer surface portion 1400 extending from an outer peripheral apex of coronal surface 22 that tapers outwardly, a cylindrical surface portion 1401 having a surface that is generally parallel to the longitudinal axis of implant 4 and extends from the apex of surface 1400, and an inwardly tapered portion 1402 extending from the apex of cylindrical surface portion 1401. As shown in fig. 14, a threaded portion 1403 is provided on the outer surface of the implant 4, and an inner bore is provided in the implant 4 to receive the abutment 5. One or more spaces, such as 1410, 1411, 1412, and 1413, may be formed by the implant 4 and abutment 5 assembly.

The abutment 5 and the implant 4 may be manufactured from titanium alloy or other desired materials by conventional manufacturing methods.

Figures 15-17 show alternative embodiments of an impression coping and a dental prosthesis part for use with the impression coping according to the invention. Fig. 15 shows an impression cap 1501 having a coronal end 1502, a root tip end 1503, and a longitudinal axial direction L. The impression cap 1501 is positioned over an abutment 1505 and an abutment 5 may be coupled to the implant 1504.

The impression cap 1501 forms an internal recess with a frustoconical inner surface 1506 that is closed at the coronal end 1502 of the cap 1501 and open at the root-apical end 1503 of the cap 1501. The inner concave inner surface 1506 of the cap 1501 is generally frustoconical in shape, tapering inwardly from the root tip 1503 to the coronal end 1502 of the cap 1501.

The outer surface 1507 of the impression cap 1501 may be contoured as shown in fig. 15-17. The outer surface of cap 1501 may be provided with a number of features, for example, to assist in positioning cap 1501 over abutment 1505 and/or to facilitate embedding cap 1501 within impression material. Specifically, the cap 1501 includes a coronal extending alignment structure 1510, the structure 1510 extending from a generally planar top surface 1517 of the cap 1501 to assist in aligning the cap 1501 on the abutment 1505. Additionally or alternatively, one or more protrusions of different designs and sizes, such as circumferential protrusion 1511, may be provided extending radially from the outer surface and/or the coronal surface of the cap 1501. An inwardly tapered portion 1518 of the surface 1507 may be provided towards the apex of the cap 1501.

As with the impression coping described above with reference to fig. 1-14, the inner surface 1506 of the impression coping 1501 is provided with an engagement feature 1512, the engagement feature 1512 comprising a circumferential or partially circumferential rib or other protrusion extending from the inner surface 1506 towards the longitudinal axis L of the coping 1501. The engagement features 1512 are positioned to engage with corresponding partial circumferential recesses 1520 formed within the inner surface of the abutments 1505. Engagement feature 1512 is positioned such that a distance D1 between a coronal surface of implant 1504 (where abutment 1505 emerges from implant 1504) and engagement feature 1512 is greater than a distance D2 between engagement feature 1512 and a coronal surface 1592 of abutment 1505. The engagement features 1512 may also include tapered crown and root tip surfaces as described above with reference to FIG. 4.

Near the root tip 1503 of the cap 1501, the inner surface 1506 of the cap 1501 may also include one or more chamfered surfaces, such as surface 1513, and one or more longitudinally extending generally cylindrical engagement surfaces, such as surface 1515.

In the fig. 15 embodiment, surface 1513 is chamfered outwardly to correspond to the angled surface of implant 1504. As shown in fig. 15-16, surface 1515 corresponds to a longitudinally extending cylindrical surface of implant 1504. Additional and/or alternative chamfered and/or longitudinal surfaces may be provided on the inner surface 1506 of the cap 1501 if precise assembly of the cap 1501 to the implant 1504, abutment 1505, or other component is desired. An additional tapered surface 1530 may be provided on the inner surface 1506 at the root apex base of the cap 1501, for example, to assist in positioning the cap 1501 on the implant 1504. A vent 1523 may be formed in the interior of the cap 1501 between the coronal end 1592 of the abutment 1505. The vent may be reached through a baffle or flexible flap 1519 formed to allow air to flow through the vent 1523 while blocking impression material from entering the cap 1501 through the vent. The flexible flap 1519 may be positioned within a recess 1525 formed within the crowned surface 1517 of the cap 1501. One or more structures, such as structure 1527, may be provided to position the flexible cover sheet 1519 in a position over the vent 1523 (see fig. 16). In the illustrated embodiment, structure 1527 is adjacent to space 1526. The coronal surface portion 1521 of the inner surface 1506 may also abut an outer circumferential portion of the top surface 1592 of the abutment 1505.

Figure 16 shows a view of the impression cap 1501, abutment 1504 and implant 1505 of figure 15 rotated 90 degrees about the longitudinal axis L of the cap 1501. An alignment feature is provided on an inner surface 1506 of the cap 1501. Specifically, a substantially flat inner surface portion 1509 is provided that extends longitudinally and substantially parallel to the longitudinal axis L of the cap 1501. Surface portion 1509 aligns with extension 1510 on coronal end 1502 of cap 1501 to assist in alignment of cap 1501 on abutment 1505. A curved surface portion 1508 is provided at the root tip of the surface portion 1509 to correspond to the geometry of the inner surface of the abutment 1505 (similar to the abutment 5 described above with reference to figure 10).

Fig. 17 shows an impression coping 1501 for use with a isomorph 1700. When the cap 1501 is positioned on the isomorph 1700, the surfaces 1513, 1515, and 1530 may form a gap between the surface of the isomorph 1700 and the inner surface 1506 of the cap 1501, as shown in FIG. 17. The isomorph 1700 is provided with a groove or concave surface portion 1720 that receives an engagement feature 1512 of the cap 1501 to enable the cap 1501 to engage with the isomorph 1700.

The impression cap 1501 may be fabricated from acetal or any other desired material by conventional molding or other fabrication methods.

It is contemplated that therapeutic caps, depleted crowns, and other types of crowns may be provided with engagement features such as features 1512 described herein to enable removable engagement of the cap with temporary or permanent abutments, analogues or replicas, and or other prosthetic components.

In alternative embodiments (not shown), various shapes and configurations of the engagement features functionally comparable to the grooves or recesses 20, 1520, or 1720 may be provided on an abutment such as abutment 5 or abutment 1505, on a replica such as replica 1700, or on other prosthetic tooth components. Such engagement features may, for example, extend around the entire perimeter of the component, may extend only partially around the perimeter of the component, or may be provided as a plurality of grooves, recesses or other engagement features at various locations as required to enable removable engagement of the cap 1 or 1501 with the component.

It will be apparent that the above-described alignment features including the alignment surfaces 8, 9, 1508 and 1509 and the coronal extending alignment surfaces 10 and 1510 are optional and may be omitted without departing from the scope of the invention. Thus, the impression cap 1 or 1501 can be designed to have a generally frustoconical inner surface 6 or 1506 with an engagement feature 12 or 1512.

Further, in accordance with the present invention, single piece implants (where a single piece is used as both an implant and an abutment), multi-piece implants, analogs, and other prosthetic components can be manufactured with engagement features such as grooves 20 or 1520 to enable removable engagement with the engagement features of impression cap 1 (or 1512 of cap 1501) and alignment surfaces such as surfaces 1000 and 1010.

From the foregoing description and drawings, it will be appreciated by those of ordinary skill in the art that the specific embodiments shown and described are for purposes of illustration only and are not intended to limit the scope of the present disclosure. One of ordinary skill in the art will recognize that the invention may be embodied in other specific forms without departing from its spirit or essential characteristics. Reference to details of particular embodiments is not intended to limit the scope of the invention. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description of the preferred embodiments.

Claims (20)

1. A dental crown for removable engagement with a prosthetic component extending from gingival margin tissue, comprising:

a body having a frustoconical outer surface, an inner recess, a closed coronal end, and an open apical end;

a frustoconical inner surface disposed within the inner recess; and

an engagement feature formed as a protrusion on the inner surface and extending at least partially circumferentially around the inner recess, wherein the engagement feature is positioned closer to the coronal end of the inner recess than to the apical end of the inner recess.

2. The apparatus of claim 1, further comprising a crown tapered surface and an apex tapered surface, wherein the crown and apex tapered surfaces form a crown edge and an apex edge, respectively, of the engagement feature.

3. The apparatus according to claim 2, wherein said crown and apical tapered surfaces have taper angles designed to effect snap-fit engagement of said engagement feature with said prosthetic tooth component.

4. The apparatus according to claim 1, further comprising a generally cylindrical engagement surface disposed on said inner surface at an open apical end of said dental crown, said cylindrical engagement surface extending generally parallel to a longitudinal axis of said dental crown and being disposed to receive a cylindrical surface portion of said prosthetic tooth component extending from said gingival margin tissue; and

a first chamfer surface disposed on the inner surface coronal adjacent the cylindrical engagement surface, the first chamfer surface forming a first angle with respect to the longitudinal axis of the crown and disposed coronal adjacent a first surface portion of the cylindrical surface portion to accommodate the prosthetic tooth component.

5. The apparatus according to claim 1, further comprising a coronal extension alignment structure positioned at said closed coronal end.

6. The apparatus according to claim 5, further comprising a flat alignment surface extending longitudinally on said inner surface, wherein said flat surface is aligned with said coronal extension alignment structure.

7. A prosthetic tooth component for use with the dental crown of claim 1, comprising a groove for engaging the engagement feature within the inner recess of the dental crown to enable removable engagement of the dental crown with the prosthetic tooth component.

8. The prosthetic tooth component of claim 7 wherein the groove further comprises a crown tapered surface and an apical tapered surface corresponding to the crown and apical tapered surfaces of the engagement feature on the crown.

9. The prosthetic tooth component of claim 7 wherein the component comprises an abutment.

10. The prosthetic tooth component of claim 7 wherein the component comprises an implant.

11. A dental prosthesis part according to claim 7, characterised in that the part is a isomorph.

12. A dental implant assembly comprising:

an impression coping for removable engagement with a prosthetic tooth component extending from gingival margin tissue, having:

a body having a frustoconical outer surface, an inner recess, a closed coronal end, and an open apical end;

a frustoconical inner surface disposed within the inner recess; and

an engagement feature formed as a protrusion on the inner surface and extending at least partially circumferentially around the inner recess, wherein the engagement feature is positioned closer to the coronal end of the inner recess than to the apical end of the inner recess; and

a prosthetic tooth component comprising a groove for engaging the engagement feature within the inner recess of the impression cap to enable removable engagement of the dental crown with the prosthetic tooth component.

13. The dental prosthesis assembly of claim 12, wherein the impression cap further comprises a crown tapered surface and an apex tapered surface, wherein the crown and apex tapered surfaces form a crown edge and an apex edge, respectively, of the engagement feature.

14. The dental implant assembly of claim 13, wherein the crown and apical tapered surfaces of the impression cap have a taper angle designed to effect a snap-fit of the engagement feature with the groove of the dental implant component.

15. The dental implant assembly of claim 12, wherein said impression cap further comprises a generally cylindrical engagement surface disposed on said inner surface at said open root tip, said cylindrical engagement surface for engaging a cylindrical surface portion of said dental implant component extending from said gingival margin tissue; and

a first chamfered surface disposed on the inner surface coronal adjacent the cylindrical engagement surface, the first inclined engagement surface inclined at a first angle with respect to a longitudinal axis of the impression cap and arranged to receive a first surface portion of the coronal adjacent the cylindrical surface portion of the prosthetic tooth component.

16. The dental implant assembly of claim 12, wherein the impression coping further comprises a coronal extension alignment structure positioned on the closed coronal end.

17. The dental prosthesis assembly of claim 12, wherein the impression cap further comprises a flat alignment surface extending longitudinally on the inner surface, wherein the flat alignment surface is aligned with the coronal extension alignment structure, and the dental prosthesis component comprises a flat outer surface portion aligned with the flat alignment surface and the coronal extension alignment structure of the impression cap.

18. The dental implant assembly of claim 12, wherein the dental implant component comprises an abutment.

19. The prosthetic tooth assembly of claim 12 wherein the prosthetic tooth component comprises an implant.

20. The dental implant assembly of claim 12, wherein the dental implant component is a replica.