Healing Cap System

This invention relates generally to the field of dental implants, more particularly, to apparatus of second stage healing caps for correctly aligning dental implants into the patient's bone and providing accurate crown or bridge insertion into the gingiva.

Having a crown or bridge affixed to a patient is achieved by basically a three stage process.

In the first stage, the dental surgeon removes the dead or cracked natural tooth. The surgeon then cuts down through the gingiva tissue to expose the underlying bone. The surgeon then burrs into the bone to insert a dental implant. The dental implant will act as the permanent anchor for the crown (which will be created during the third stage). The implant basically comprises a threaded bore to receive a retaining screw that is coupled at some portion to the crown. The crown is then secured to the dental implant by that retaining screw. The dental implant itself can be either press-fitted down into a hole drilled in the bone or it can be screwed down into that hole. The dental implant may have a male or female anti-rotational coupling (e.g., an external hex or internal hex, respectively) but in any case the entrance to the screw hole is located in the center of the anti-rotational coupling. A cover is then placed over the screw hole in the center of the anti-rotational coupling and the overlying gingiva tissue is then closed back over the implant. It is extremely important that sufficient time be allotted for osseointegration, i.e., the surrounding bone secures itself around the dental implant. This is achieved by allowing 3-4 months of healing time for dental implants in the lower jaw and 5-6 months of healing time for dental implants in the upper jaw.

Following this first stage healing, second stage healing begins. In particular, the surgeon cuts away the gingiva surrounding the head of the dental implant, removes the cover and then inserts a second stage healing cap which is releasably secured (e.g., screwed down) onto the head of the dental implant. A typical second stage healing cap is either cylindrical in form and/or circular in cross-section. In all cases, the healing cap is designed to maintain a cylindrical chamber, during second stage healing, from the gingiva crest (the top of the gum) down to the opening in the dental implant.

After approximately three weeks, the stitches are removed and the restorative doctor and dental technician then begin the third stage: creating a crown that is permanently secured to the dental implant. In particular, the healing cap is removed and a transfer impression is taken of the jaw containing the implant. The transfer impression basically is a mold that transfers the patient's dental information from the patient to a stone model. To preserve the location of the opening to the dental implant when creating the stone model, an impression post is coupled to the head of the implant. The impression post transfers the position information of the dental implant in the patient's mouth to the stone model. The impression post also prevents the transfer impression mold from entering into the opening to the dental implant.

When the transfer impression is completed and removed from the patient's mouth, the impression post is disengaged from the dental implant and reinserted into the hole preserved in the transfer impression. An implant analog is then attached to the impression post and the stone model is ready to be made.

The healing cap is then reinserted into the dental implant in the patient's mouth to continue to preserve the cavity in the gingiva until either the temporary and, eventually, the permanent crown is in place. A stone model is created from the transfer impression and the stone model becomes the model from which the restorative doctor and the dental technician create the crown/bridge. It is the model of the cavity, preserved in the stone model, that determines the final shape of the crown/bridge.

The following constitute various examples of United States patents disclosing healing cap systems.

For example, U.S. Pat. No. 5,073,111 (Daftary) discloses a healing cap system in the form of a custom dental implant that is embedded in the jawbone and which can receive frusto-conical shaped healing caps and any one of three abutments that have different emergence profiles. Although this patent states that the healing caps are dimensionally similar to the tooth previously removed, the healing caps are all circular in cross-section and do not differentiate among the various possible tooth dimensions. Furthermore, the healing cap in this patent is coupled to the implant by being rotated so that the threaded surface of the healing cap is secured within the implant bore. However, this rotation defeats the purpose of an anti-rotational coupling that is located on the head of conventional dental implants. In addition, the rotation required by this system could mar or score the implant head during securement of the healing cap to the implant.

In U.S. Pat. No. 5,035,619 (Daftary), which is a continuation-in-part of the No. 5,073,111 patent, there is disclosed a two-piece (upper and lower) healing cap similar in design to the healing caps disclosed in the No. 5,073,111 patent. The added feature of having an upper and lower portion of a healing cap permits the lower part of the healing cap (which engages the dental implant) to remain in place while the upper part is removed and the abutment (the stem which the crown will be formed upon in the third stage) is then coupled to the lower part of the healing cap, instead of having to attach the abutment directly to the implant. However, the deficiencies of the healing cap of the No. 5,073,111 patent remain in the healing caps of the No. 5,035,619 patent.

U.S. Pat. No. 5,145,372 (Daftary) is also a continuation-in-part of the No. 5,073,111 patent and discloses a reinforced two-part healing cap. To that end, the lower part houses a threaded shaft rather than a threaded bore while the upper part houses a threaded bore. As in the No. 5,035,619 patent, the upper part can be removed and an improved abutment, i.e., an abutment having a threaded bore, can be engaged to the lower part of the healing cap, instead of having to attach the abutment directly to the implant. However, as with the No. 5,035,619 patent healing cap, this improved two-part healing cap retains the same deficiencies of the healing caps of the No. 5,073,111 patent.

In U.S. Pat. No. 5,246,370 (Coatoam) there are disclosed custom dental implants comprising an open upper portion which has the same general nonuniform shape of a removed tooth bone cavity. The implants have cylindrical prongs that are embedded into the patient's jawbone. The upper portion of the implant is shaped like the removed tooth and has matching inserts that fit within the upper portion. Each insert has a lower portion that is also shaped like the particular tooth removed (in order to seat within the upper portion of the implant) and a upper portion that is circular in cross section.

In U.S. Pat. No. 5,297,963 (Daftary) there is disclosed a healing cap system similar to U.S. Pat. No. 5,035,619 (discussed previously), but teaches the use of a healing cap having an oval or elliptical shaped top surface for providing an elliptical shoulder around an associated abutment so that there can be a perfect match between the elliptical root of a tooth analogue and the abutment shoulder.

In U.S. Pat. No. 5,316,476 (Krauser) there is disclosed a dental implant for holding a dental prosthesis that used in conjunction with an outward expanding truncoconical healing cap.

In U.S. Pat. No. 5,336,090 (Wilson, Jr. et al.) there is disclosed a healing cap with varied bottom surfaces and differently-shaped channels and diverse-shaped lockwashers for obviating loosening of the healing cap when it is secured to a dental implant.

As an example of healing caps in the market, there is the Anatomic Abutments System.TM. sold by Dental Imaging Associates, Inc. of Sunrise, Fla. which includes a cylindrical healing cap that is screwed down into the dental implant.

The problem with using a cylindrical healing cap is that a cylindrical cavity in the gingiva (which the typical healing cap creates during second stage surgery) does not imitate the dental anatomy of a tooth within the gingiva tissue. In other words, the actual periphery of the tooth that is in the gingiva tissue has a cross section that is not circular but rather has something similar to facets. Maintaining the facet structure within the gingiva is necessary to create a crown that has the proper emergence profile with respect to the gingiva. However, by using a cylindrical healing cap, the restorative doctor and dental technician must wax up the crown from a cylindrical opening in the gingiva (left by the cylindrical healing cap) which is not at all representative of the tooth that once resided there. It may be true that a cross section taken at one particular depth within the gingiva may happen to be circular but that is not true for the entire cross section of the tooth that resides in the gingiva.

As one skilled in the art can appreciate, the task of the restorative doctor and dental technician is difficult because the they are trying to create a crown from a somewhat flat gingiva surface, i.e., there is no natural tooth crater that guides them in molding a tooth. In addition, the crown and gingiva interface that the restorative doctor and dental technician are trying to create cannot easily replicate the tightly sealed interface that a natural tooth growing out of the gingiva would have.

Furthermore, once the dental implant is in place, the restorative doctor and dental technician have no room for adjusting the orientation of the tooth, i.e., the crown screw hole must be perfectly aligned with the vertical chamber left by the healing cap or else the crown will not be positioned correctly. Creating a crown which has a portion that must drastically taper to conform to the cylinder head of an implant is improper and thereby does not permit the stimulation of soft tissue.

Moreover, where external hex implants are used (i.e., dental implants having a hexagonal-shaped anti-rotational coupling projecting upwards) the conventional cylindrical healing caps do not engage and seat over the hex but rather must be secured on top of the hex. In particular, on external hex implants the procedure to date is to select a separate spacing abutment to place over this particular type of implant that will allow the emergence procedure to begin at the gingival crest (the top surface of the gum). Because healing caps on these type of implants are also of a circular design, the height of the healing caps are frequently placed too high. The healing caps come in different millimeters of height. When the healing cap is above the height of gingival tissue the circumference of metal will show.

The result of all of this is that the restorative doctor and dental technician are trying to formulate a crown/bridge from criteria that are lost.

Therefore, a need exists for apparatus for creating and then maintaining the natural gingiva cavity throughout second stage healing that allows a restorative doctor and dental technician to easily and accurately create a close replica of the removed tooth that not only looks natural (i.e., being aligned with surrounding teeth and having proper tooth emergence profile from the gingiva) but also avoids soft tissue degeneration and destructive plaque build-up.

Furthermore, there is a need for a second stage healing cap that is compatible with a variety of standard dental implants and whereby the healing cap does not score or damage the anti-rotational coupling of the implant whenever the cap is engaged/disengaged from the implant.

Accordingly, it is the general object of this invention to provide apparatus which address the aforementioned needs.

It is another object of this invention to provide apparatus that the surgeon can place during first stage surgery on top of the implant and fold the surrounding tissue over to ascertain whether there is enough depth of soft tissue and/or compensate for by shaving bone, if necessary.

It is still yet another object of this invention to provide a way to ascertain earlier on in dental surgery whether a graft will be needed to enhance the soft tissue for securing the implant's emergence.

It is yet another object of this invention to provide a healing cap that provides a dental anatomical replica of any natural tooth wherein the replica is inserted in the gingiva, at the proper tooth location, during second stage healing to maintain the proper emergence profile of the natural tooth.

It is yet a further object of this invention to provide a healing cap that can be releasably secured to any dental implant without scoring or damaging the anti-rotational coupling of the dental implant.

It is still a further object of this invention to provide an anatomically designed healing cap of a posterior tooth for use during second stage healing wherein the healing cap compensates for a more lingually or more buccally located dental implant, thereby maintaining the proper arch formation of the crown with respect to surrounding teeth.

It is still another object of this invention to provide a healing cap having an occlusal lip around the top to inhibit the overgrowth of gingiva tissue during second stage healing.

It is still another object of this invention to provide a healing cap that enables a crown to be created having proper tooth contour thereby avoiding soft tissue retardation that usually occurs when crowns having improper tooth contours are used.

It is still another object of this invention to provide a healing cap that enables a crown to be created having proper tooth contour, thereby avoiding soft tissue recession which permits food impaction under the crown that usually occurs when crowns having improper tooth contours are used.

It is still another object of this invention to provide apparatus that enables a crown to be created having proper tooth contour, thereby allowing occlusion function of food to stimulate tissue at the gingival area that does not occur when crowns having improper tooth contours are used.

It is still another object of this invention to provide apparatus that enables a crown or bridge to be created having proper tooth contour thereby avoiding destructive plaque build-up between the crown and gingiva that usually occurs when crowns having improper tooth contours are used.

It is still another object of this invention to provide apparatus for maintaining sufficient embrasure room for cleaning between multiple adjacent crowns by the use of healing cap dowels and alignment indicators during first and second stage surgery.

It is still another object of this invention to provide apparatus for facilitating and increasing the accuracy of creating cementable or screw-down types of crowns for use with any restorative castable cylinder.

It is still yet another object of this invention to provide a surgery kit that provides the dental surgeon with all the necessary healing caps, alignment indicators and related apparatus for locating and verifying dental implant locations, including healing cap positioning and alignment.

It is still yet another object of this invention to provide a laboratory kit that provides the dental technician with healing caps, healing cap dowels, burnout sleeves and hollow cylinders necessary for creating the crown.

These and other objects of the instant invention are achieved by providing a healing cap to be used in a predetermined position in the gingiva tissue of a patient during second stage surgery of a dental implant for mounting a crown replicating a tooth naturally residing at that position. The implant has a head with an anti-rotational coupling. The healing cap forms a cavity in the gingiva tissue when installed in a patient's mouth whose shape replicates a portion of the tooth. The healing cap comprises a unitary member having coupling means. The unitary member has an outer surface including portions having at least two predetermined dimensions, which comprise the mesio-distal dimension of the neck of the tooth and the labio-lingual dimension of the neck of the tooth. These dimensions are representative of the anatomical dimensions of the corresponding portions of the tooth which was located within the gingiva tissue. The coupling means engages and mates with the anti-rotational coupling on the head of the dental implant. This anti-rotational coupling also forms the opening to a threaded bore. The unitary member and the coupling means are adapted to be aligned with the anti-rotational coupling of the dental implant and further comprise a retaining screw passing through the unitary member and the coupling means adapted to engage the dental implant. The retaining screw is releasably adapted to secure the healing cap against the head of the dental implant.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is an occlusal (top) plan view of a Category IV healing cap constructed in accordance with one aspect of this invention and shown inserted in the lower jaw.

FIG. 2 is an enlarged sectional view taken along line 2--2 in FIG. 1;

FIG. 3 is an enlarged sectional view taken along line 3--3 of FIG. 1;

FIG. 4A is a sectional view taken along line 4A-D of FIG. 3;

FIG. 4B is a sectional view taken along line 4A-D of FIG. 3;

FIG. 4C is a sectional view taken along line 4A-D of FIG. 3;

FIG. 4D is a sectional view taken along line 4A-D of FIG. 3;

FIG. 5 is a view like that of FIG. 2 but showing an anterior healing cap inserted in the lower jaw;

FIG. 6 is a top plan view of a Category I healing cap;

FIG. 7 is a top plan view of a Category II healing cap;

FIG. 8 is a top plan view of a Category III healing cap;

FIG. 9 is a top plan view of a Category V healing cap;

FIG. 10 is a top plan view of a Category VI healing cap; and

FIG. 11 is a top plan view of a Category VII healing cap;

FIG. 12 is an isometric view of the mouth of a patient after the healing cap of this invention has been used to create an appropriately shaped anatomical cavity for a crown and showing the initial step in the making of an impression for the crown;

FIG. 13 is an exploded isometric view of various components used to make a dental mold, i.e., stone model, for the crown;

FIG. 14 is an isometric view of the stone model made from the impression mold;

FIG. 15 is a vertical sectional view of a prepped tooth portion of a crown using a burnout sleeve constructed in accordance with one aspect of this invention;

FIG. 16 is a view similar to FIG. 15 but showing another burnout sleeve constructed in accordance with another aspect of this invention;

FIG. 17 is a plan view like that of FIG. 1 but showing an alignment device constructed in accordance with another aspect of this invention.

FIG. 18 is an enlarged sectional view taken along line 2--2 of FIG. 1 but depicting the Morse taper couplings of the present invention and the dental implant;

FIG. 19 is a sectional view taken along line 19-20 of FIG. 18 depicting anti-rotational couplings having a Morse taper; and

FIG. 20 is a sectional view taken along line 19-20 of FIG. 18 depicting circular couplings having a Morse taper.

It must be stated from the outset that because many of the maxillary (upper) and the mandibular (lower) teeth have dental anatomy dimensions that are similar (see Tables A and B), there need be only seven categories (I-VII) of second stage healing caps (occlusal views depicted in FIGS. 1 and 6-11) constructed in accordance with the present invention in order to enable a crown to be made for any tooth. Categories I-III and VII are healing caps for use with anterior (front) teeth, whereas Categories IV-VI are healing caps for use with posterior (back) teeth.

Referring now in greater detail to the various figures of the drawing wherein like reference characters refer to like parts, a "Category IV" second stage healing cap constructed in accordance with the present invention is shown generally at 20 in FIG. 1. A healing cap 20 is used to form a cavity or crater 30 in the gingiva tissue 26 above an implant 28 to receive a crown 170a or 170b (FIGS. 15 and 16) replicating the tooth that had naturally resided there. In the exemplary embodiment shown in FIG. 1, the healing cap 20 is inserted in the patient's lower right jaw where a mandibular first bicuspid tooth 22 once resided (shown by phantom lines). (A Category IV second stage healing cap was selected as an example of a healing cap used with a posterior tooth. Therefore, the following discussion is suitable for all other healing caps 20 that are used with posterior teeth, i.e., Categories V and VI).

As can be seen more clearly in FIG. 2, the healing cap 20 basically comprises a unitary member 24. The member 24 comprises a material, preferably metal or plastic, that is resilient and compatible with gingiva tissue. Examples of compatible metals include stainless steel, titanium, gold, copper or brass; examples of compatible plastic include nylon or carbon glass.

In accordance with one aspect of this invention, the member 24, has the dimensions of the first bicuspid tooth 22 which had resided in the gingiva tissue 26. The member 24 is positioned in the gingiva tissue 26 at the desired site, i.e., where the first bicuspid tooth 22 resided, during second stage healing, thereby establishing a crater 30 in the gingiva tissue 26 that accurately resembles the recess in the gingiva tissue 26 that once surrounded the first bicuspid tooth 22.

In accordance with a preferred embodiment of this invention, each member 24 has predetermined crucial dimensions corresponding to at least the mesio-distal dimension and the labio-lingual dimension which describes the periphery of the tooth, from the bone upward through the gingiva. In fact, the housing may be made using in addition to the mesio-distal dimension and the labio-lingual dimensions other well known tooth dimensions such as those set forth in Tables A and B herein. These tables are based on the two tables found in Tooth Anatomy by Dr. Henry A. Linek, D.D.S., copyright 1948 and 1949. The two crucial dimensions are designated by an asterisk in the Tables A and B.

As can be seen clearly in FIG. 2, an occlusal lip 32 forms the top periphery of the member 24. This lip 32 ensures that the gingival crest 34 (i.e., the top surface of the gingiva tissue) does not resorb during second stage healing, thereby preventing the gingiva tissue 26 from closing up the crater 30. Without the lip 32, the gingiva tissue 26 would grow over the top of the member 24 during second stage healing. In particular, when the gingiva tissue 26 is cut in order to insert the healing cap 20, the incision is made in a mesial-distal orientation. After the healing cap 20 is releasably secured to the dental implant 28, the sliced gingiva tissue 26 is pressed together around the healing cap 20 and under the occlusal lip 32; stitches in the buccal-lingual direction are then made across the sliced gingiva tissue 26 wherein second stage healing begins.

The unitary member 24 of the healing cap 20 has a coupling means for securing the healing cap 20 to the implant 28. In order to best understand the construction and operation of the coupling means, it is necessary to first discuss the structure of and method of use of conventional dental implants.

To that end, during first stage surgery, the dental implant 28 is permanently secured in the patient's jaw bone 36. Generally, dental implants have a central bore that receives the threaded end of a retaining screw in order to enable a conventional healing cap or crown to be secured to the implant. FIG. 2 shows a conventional dental implant 28 having a central bore 38 that receives the threaded end 40 of a retaining screw 42. The screw 42 secures the healing cap 20 to the implant 28, as will be discussed later. Conventional dental implants typically have an anti-rotational coupling, male or female, located at the top or head of the implant which engages a mating female or male coupling, respectively, of the crown to prevent the crown from rotating on top of the implant during securement. The opening to the central bore 38 is located in this mating female or male coupling. Thus, as can be seen in FIG. 2, the dental implant 28 has a male (external) anti-rotational coupling 44, having an opening 46, located on the head 48 of the implant 28.

The coupling means of the healing cap 20 of this invention has a mating female anti-rotational coupling 50 which seats around the implant coupling 44 during engagement while aligning a central bore 52 with the opening 46. This alignment permits the passage of the threaded end 40 of the retaining screw 42 through the healing cap 20 and down into the implant 28. It is important to understand that the unitary member 24 of the present invention can be manufactured to have a male anti-rotational coupling to engage a dental implant which has a female anti-rotational coupling located at its head 48. The depiction of a female anti-rotational coupling 50 in the unitary member 24 is by way of example, not limitation.

In addition, dental implants in general may have a variety of anti-rotational coupling shapes. These shapes are shown in FIGS. 4A-4D. In particular, FIG. 4A shows a square anti-rotational coupling 44a, whereas FIG. 4B shows a triangular anti-rotational coupling 44b, FIG. 4C shows a hexagonal anti-rotational coupling 44c, and FIG. 4D shows an octagonal anti-rotational coupling 44d. As such, the healing cap 20 that will be selected to engage a particular dental implant secured in the patient's jaw will have a mating anti-rotational coupling 50a, 50b, 50c or 50d, respectively. Therefore, the unitary member 24 which has been designed herein can fit any male or female anti-rotational configuration on the head of a dental implant and can be altered to fit any future design.

To lock the healing cap 20 onto the dental implant 28, the retaining screw 42 is then passed down through the opening 54 and down through the central bore 52 where the threaded end 40 is screwed into the dental implant bore 38.

Furthermore, for dental implants 28 having a female coupling 244 utilizing a "Morse" tapered design 245, the unitary member 24 has a corresponding male coupling 250 to engage and mate with the implant's 28 Morse taper. In particular, if the dental implant anti-rotational coupling 244 (FIG. 18) exhibits a Morse taper 245, a corresponding Morse taper 251 (FIG. 19) can be incorporated into the unitary member 24 coupling 250. Alternatively, as shown in FIG. 20, if the dental implant coupling 244 exhibits a Morse taper 245 but has no anti-rotational characteristic (i.e., coupling 244 has no square shape 44a, no triangular shape 44b, no hexagonal shape 44c, or no octagonal shape 44d as depicted in FIGS. 4A-4D), the unitary member 24 coupling 250 can be configured to have a corresponding Morse taper 251 (FIG. 20) also with no anti-rotational characteristic (i.e., coupling 50 has no square shape 50a, no triangular shape 50b, no hexagonal shape 50c, or no octagonal shape 50d as depicted in FIGS. 4A-4D).

As can be seen in FIGS. 2-3, the unitary member 24 also has an upper chamber 56 that houses the head 58 of the retaining screw 42. The purpose of the chamber 56 is to ensure that head 58 does not project upward beyond the top surface 60 of the unitary member 24 but rather remains recessed within the unitary member 24 during securement of the healing cap 20 to the dental implant 28. A light curable filler 62 is provided within the chamber 56 after the retaining screw 42 has been tightened, as will be described later. As can be seen in the occlusal view of FIG. 1, the chamber 56 has a rectangular shape, having a buccal wall 64a, a lingual wall 64b, a mesial wall 64c and a distal wall 64d. A groove 66a (FIG. 3) is milled along the distal wall 64c and another groove 66b (FIG. 2) is milled along the mesial wall 64d. The purpose of these grooves is to provide recesses into which the light-curable filler 62 can flow and harden, thereby securing the hardened filler within the chamber 56. The filler 62 serves to close off the chamber 56 so that the top surface 60 of the unitary member 24 forms a smooth flat surface precluding penetration of material, e.g., foreign particles, during second stage healing when the healing cap 20 is secured within the patient's mouth. As shown in FIG. 1, the filler 62 even penetrates the slot opening 68 in the retaining screw's head 58 and fills that slot. The slot 68 had previously served to receive the driver device, e.g., screwdriver, (not shown) to lock the retaining screw 42 down into the dental implant 28.

In order to imitate the natural curvature of the cavity 30 in the gingiva 26, the bottom surface 70 of each unitary member 24 is tapered at the edges 72 so that the bottom surface 70 is in contact with either the head 48 of the implant 28 or the gingiva tissue 26 only. No part of the jawbone 36 is to be in contact with the healing cap 20 and as such the edges 72 are tapered. This tapering will be imitated when the crown is being created since the crater 30 reflects this tapering during the second stage healing and a crown mold is made from this crater 30.

The other posterior healing cap 20 categories, i.e., Category V (FIG. 9) and Category VI (FIG. 10) operate in the same fashion.

A healing cap 20 for an anterior tooth is shown in FIG. 5. Therefore, the structure of Category I (FIG. 6), Category II (FIG. 7), Category III (FIG. 8) and Category VII (FIG. 11) healing caps 20 can be discussed with reference to FIG. 5. Anterior healing caps 20 also comprise a unitary member 74. The unitary member 74 also comprises a material, preferably metal or plastic, that is resilient and compatible with gingiva tissue. Examples of compatible metals include stainless steel, titanium, gold, copper or brass; examples of compatible plastic include nylon or carbon glass. Moreover, the anti-rotational coupling 76 of the member 74 can take the form of a male or female coupling having a square, triangular, hexagonal or octagonal shape depending upon the type of dental implant 28, as discussed earlier regarding posterior healing cap unitary members 24. In addition, all anterior healing caps 20 have an occlusal lip 78 which serves the same purpose as discussed earlier. Furthermore, the central bore 52 and its corresponding opening 54 allow for passage of a retaining screw 42 having an associated head 58 and slot 68, as discussed earlier with respect to the posterior healing caps 20.

Furthermore, for dental implants 28 having a female coupling utilizing a "Moore's" tapered circular design, the unitary member 74 has a corresponding male coupling to engage and mate with the implant's 28 Moore's taper. In particular, if the dental implant anti-rotational coupling 44 exhibits a Moore's taper, a corresponding Moore's taper can be incorporated into the unitary member 74 coupling 76. Alternatively, if the dental implant coupling 44 exhibits a Moore's taper but has no anti-rotational characteristic (i.e., coupling 44 has no square shape 44a, no triangular shape 44b, no hexagonal shape 44c, or no octagonal shape 44d as depicted in FIGS. 4A-4D), the unitary member 74 coupling 76 can be configured to have a corresponding Moore's taper also with no anti-rotational characteristic (i.e., coupling 76 has no square shape 50a, no triangular shape 50b, no hexagonal shape 50c, or no octagonal shape 50d as depicted in FIGS. 4A-4D).

Unlike the posterior healing caps 20, the small size of anterior healing caps 20 requires that the filler grooves (only one, 80, of which is depicted in FIG. 5) run along the lingual 82 and buccal 84 walls (FIGS. 6-8, 11) of the upper chamber 86, rather than along the distal 64c and mesial 64d walls as in the posterior healing caps 20. A light-curable filler 62 is allowed to fill the upper chamber 86, as discussed earlier with respect to the upper chamber 56.

As with the posterior healing caps 20, the unitary members 24 for anterior healing caps 20 also have tapered bottom edges 88 for the same reasons discussed earlier.

In addition, to prevent the top edge of the anterior healing caps 20 from obstructing tongue movement, the top edge of the lingual side is tapered. In particular, lingual edge surfaces 90 (Category I, FIG. 6), 92 (Category II, FIG. 7), 94 (Category III, FIG. 8) and 96 (Category VII, FIG. 11) are tapered, i.e, they are canted downward into the page, away from the plane containing the opening to the upper milled chamber 86.

As discussed earlier with respect to posterior healing caps 20, the unitary members 74 of anterior healing caps 20 have predetermined crucial dimensions corresponding to at least the mesio-distal dimension and the labio-lingual dimension, as set forth in Tables A and B.

It should be understood that the posterior healing caps 20 comprising the unitary members 24 and the anterior healing caps 20 comprising the unitary members 74 for all seven categories can be provided in the surgical kits and the laboratory kits disclosed in application Ser. No. 08/216,908 (now U.S. Pat. No. 5,492,471).

In order to minimize the misalignment of the dental implant 28 before it is permanently implanted in the jawbone 36, the system of the subject invention not only includes the heretofore discussed healing caps 20 but also two pre-surgery devices, namely, plastic dowels and an implant alignment indicator 140.

The plastic dowels are solid plastic replicas of the Category I-VII healing cap unitary members 24 and 74. These dowels are to be used at the outset by the dentist for initially locating where the dental implant 28 will be secured. Because the doctor will want to be able to verify any proposed location of an implant 28, it necessary to make a model of the dowel which the dentist can cut into, mark up, etc. in order to finalize the implant location. The dowel itself is not to be altered.

Initially, an upper and lower study model is taken of the patient's teeth by the dentist. The doctor then sends these models to the laboratory. The technician simply picks a particular dowel (e.g., a bicuspid, molar, or canine dowel), and releasably secures it to the study model by way of an adhesive (e.g., using a "fillet activator", which is a glue that hardens by spraying a liquid to it). The dowel can then be positioned in the proper arch formation in the study model to designate the area where an implant 28 will be placed.

Creating a model of the dowels is as follows: after the dowels are secured to the model, a vacuum pressed plastic stint (not shown) is made. The stint is trimmed and removed as usual and the dowel can be removed from the stone model and returned. The stint will now have dowel impressions. The dowel impressions in the stint will be filled with a clear acrylic which hardens. After the acrylic hardens, the dowel impressions are removed from the stint. These "models of the dowels" can then be placed back on the study model and cured, and sent to the surgeon or periodontist in charge of the surgery. They now have an accurate representation of where the healing cap 20 can be placed. Since the dowel and the healing cap 20 are of the same anatomical dimensions of the natural teeth being replaced, the overall view of the proper anatomy design is increased.

The implant alignment indicator 140 is shown in FIG. 17 and serves to facilitate the alignment of the implant before it is permanently secured. The indicator 140 basically comprises an elongated shaft having a male or female tip at the distal end of the shaft. The tip is constructed to mate with the anti-rotational coupling of the implant. The proximal end of the indicator 140 comprises a pair of cross members 142 and 144 which are disposed perpendicularly to each other and to the longitudinal axis of the shaft. These members provide alignment cues in the buccal-lingual directions and the mesial-distal directions, respectively. In particular, after the site for the dental implant 28 has been selected and the surgeon is preparing to permanently tighten the dental implant 28 into the bone 36, the surgeon preferably engages the implant alignment indicator 140 with the anti-rotational coupling 44 of the implant 28. The surgeon then sights down at the cross members 142 and 144 to ascertain whether the implant 28 needs to be rotated any further down into the bone 36 to ensure that the healing cap 20 will be oriented correctly when it is engaged with the implant head 48. This will, in turn, assure proper alignment in arch-form with surrounding teeth. In addition, the indicator 140 allows the surgeon to visualize the attitude of the healing cap 20 when it resting on the implant 28. The attitude of the healing cap 20 will determine how the surrounding gingiva tissue 26 will heal around the healing cap 20, thereby establishing how the crown will emerge from the crater 30. Therefore, the alignment indicator 140 assures the surgeon whether there is proper arch alignment and proper angulations of the gingiva tissue emergence. Furthermore, the surgeon can at this point, also determine if a soft tissue graft will be necessary to ensure the proper angulations. If there is not enough soft tissue to establish the proper angulation, the surgeon can schedule a graft operation to be at the next stage, thereby avoiding a later surgery just to accomplish the graft.

The alignment tool 140 can be used differently depending on the type of dental implant 28 used. For example, if the dental implant 28 to be used is a press fit, then as the dental implant 28 is being inserted into the bone 36, the surgeon will stop at least half way down (i.e., before the dental implant is finally seated) and engage the alignment tool 140 into the dental implant head 48. The surgeon will then check the buccal-lingual-mesial-distal alignment with respect to surrounding teeth and thereby make any necessary rotation of the dental implant 28 to correct the alignment. Once this is accomplished, the surgeon will then press down and thereby fully insert the dental implant 28 down into the bone 36.

If the dental implant 28 is a screw-down type, the nominal depth of a bore that is burred, i.e., drilled, in the bone 36 for dental implant 28 insertion is approximately 11 mm. The dental implant 28 is then screwed down into the bore until the 10.125 mm depth point is reached. At that point, the alignment indicator 140 is engaged into the head of the implant 28. The surgeon will then check the buccal-lingual-mesial-distal alignment and, if there is any need to rotate the implant 28 to correct for alignment, the remaining 0.875 mm will permit further rotation of the implant 28. The reason for not bottoming out the implant 28 to the bore bottom is that once a dental implant 28 is tightened down into the bone, the surgeon can not back out the implant 28 or else the implant 28 securement will be compromised.

If more than one dental implant 28 is to be implanted, an alignment indicator 140 should be provided for each implant 28 to verify the alignment thereof.

As should be appreciated by those skilled in the art, after the three weeks of healing has been completed with any type of healing cap in place, the patient has his/her stitches removed and is ready for the restorative doctor. When an anatomically correctly shaped healing cap 20 of this invention is used and has been in place for the three weeks, the proper emergence diameter of a naturally formed tooth will remain in the gingiva tissue when the healing cap 20 is removed at this time. What remains in the patient's jaw is a natural tooth cavity 30 (FIG. 12) in the gingiva tissue 26 with the head 48 of the implant 28 visible at the bottom of this cavity 30.

In accordance with standard practice, the restorative doctor takes a transfer impression 146 of the jaw which contained the healing cap 20. The transfer impression 146 basically comprises a holder with an unset mold material 150 therein that is press-fit over the teeth. This unset mold material enables an impression to be made of the teeth in the appropriate jaw. In order to preserve the opening and position of the head 48 of the implant 28, a cylindrical impression post 148 is engaged with the implant 28 in the patient's mouth as shown in FIG. 12. The transfer impression 146 is then made. Because the cavity 30 established in the patient's gingiva 26 has the natural shape of the tooth, with the subject invention there is no need to use a convention retraction cord which is typically used to substantiate the depth of the head 48 of the implant 28, i.e., a conventional cylindrical healing cap would establish a narrow cylindrical passageway through the gingiva tissue 26 leading to the head 48 of the implant 28. In particular, using the prior art the dentist would have to insert a retraction cord to force open the passageway to enable access to the head 48 of the implant 28 during securement of the crown to the implant 28, as will be discussed later.

When the transfer impression 146 is removed and inverted (as shown in FIG. 13), the now set mold material transfer impression 150 will have teeth impressions 152 and a healing cap impression therein. The healing cap impression 154 has an entrance (top) hole 156 being the diameter of the cylindrical impression post 148 that was engaged with the implant 28. Therefore, this healing cap impression 154 is an anatomically correct representation of the cavity 30, from the head 48 of the implant 28 to the gingiva crest 34. Once the impression is completed, the impression post 148 is disengaged from the implant 28. The healing cap 20 is then reinserted and secured to the implant 28 in the cavity 30 in the patient's gingiva 26.

The dentist then sends the transfer impression 146, the impression post 148 and other related items (e.g., the patient's wax bite and counter model) to the dental laboratory to make the stone model so that the crown can be made. To that end, the laboratory takes the impression post 148, inverts it and then re-inserts it into the healing cap impression 154. An implant analog 158 is then engaged on the free end 160 of the impression post 148. The implant analog 158 is replica of the implant 30, including a head 162 and an anti-rotational coupling 164 that is identical to the respective head 48 and anti-rotational coupling 44 of the implant 28 and is ordered from the manufacturer of the dental implant 28.

The laboratory uses the transfer impression and the impression post to prepare the stone model 166, which is shown in FIG. 14. This model precisely replicates the anatomically correct cavity 30, the head 48 and anti-rotational coupling 44 of the implant 28 (which is permanently secured in the patient's jaw). The stone model 166, therefore, includes an anatomically correct cavity 168 at the location of the tooth to be replicated. The cavity 168 has the dental implant analog 158 embedded in it. The analog 158 has a head 162 and anti-rotational coupling 164 which are located at the bottom of the cavity 168.

In addition, the inwardly tapered healing cap impression 154 helps to stabilize the inverted impression post 148 in the transfer impression mold 150, unlike the typical narrow cylindrical "tube" shape that is left in the transfer impression mold 150 by conventional cylindrical healing caps. By stabilizing the inverted impression post 148, the healing cap impression 154 prevents the post 148 from shifting slightly or disengaging from the impression mold 150 altogether during the transfer action. As can be appreciated by one skilled in the art, any slight movement of the impression post 148 within the transfer impression mold material 150 during transfer will degrade the replication of the cavity 30. Hence, when the stone model 166 is eventually made from the transfer impression 146, the model 166 will not be accurate, so that the crown created therefrom, will not align correctly when it is inserted into the cavity 30 in the patient's jaw.

After the stone model 166 is made, the technician removes the impression post 148 from the embedded implant analog 158 in the stone model 166 leaving the stone model as shown in FIG. 14. The stone model 166, now becomes the guidance platform from which the crown 170 or 170b (FIGS. 15 and 16) is made.

As should be appreciated by those skilled in the art, the use of the healing cap 20 during second stage surgery provides the following advantages over the prior art in creating the stone model 166. Firstly, if a conventional cylindrical healing cap was used during second stage healing, the resulting stone model 166 does not have an anatomically correct cavity 164 around the opening to the implant analog 158; therefore, the technician will have to actually cut away some of the stone to assist in re-inserting the impression post 148, thereby defeating the whole purpose of creating the stone model 166 in the first place. Secondly, as will be discussed later in the creation of a cementable crown, a soft tissue model must be created to anticipate the crown being pressed tightly down against the gingiva crest 34. Because the cementable crown developed under conventional methods will abut the gingival crest 34 rather than being seated deep into the gingiva tissue 26 (because there is no anatomically correct cavity 164 in the stone model 166) the soft tissue model gives the technician only an image of the opening to the gingiva tissue. The technician must still guess at the depth and width of the channel preserved in the gingiva. Use of the healing cap 20, on the other hand, preserves an anatomical crater inside the gingiva tissue so that the cementable crown seats properly therein. Thus, the technician does not have to guess as to how wide or deep the cementable crown must be created because the soft tissue model depicts the correct shape. Thirdly, use of the healing cap 20 preserves an anatomical cavity that permits sufficient room for the dentist to work within when creating the crown. Thus, there is no need to force retraction cord into the cavity preserved in the gingiva (which cord not only may damage the gingiva, but can be painful enough to the patient as to require anesthesia to be administered to patient before the retraction cord is used) to enable the dentist to ascertain crown depth and width.

Using the stone model 166, the technician can begin to form the crown. There are basically two types of crowns that can be created: a screw-down type and a cementable type. In most cases, the type of crown to be made is determined by the type of implant 28 used in with the patient. The different processes used in creating these crowns will be discussed briefly later. Suffice it to say for now that a screw-down type comprises one piece having a hole in the top that allows a retaining screw to be passed down through it to engage the implant 28. A cementable crown comprises two parts, a base and a cementable shell. The base of the cementable crown is secured to the implant 28 and then later the cementable shell is secured to the base. Both types of crowns require that a crown substructure, known as a "prepped tooth", be created initially.

As is known, a prepped tooth has a restorative castable cylinder (sometimes referred to as "RCC" or an "abutment") 172. The abutment or RCC provides the securement means of the crown to the dental implant.

In FIGS. 15 and 16 two exemplary crowns 170a (a molar crown) and 170b (a bicuspid crown), respectively, are shown being constructed using the teachings of this invention. Each crown includes an abutment 172 which, as is conventional, can vary in shape and size. However, the RCC 172 comprises a bore 174 to allow for the passage of a retaining screw 176. The RCC 172 also has a mating male or female coupling 178 that engages the anti-rotational coupling 44 of the implant 28. The RCC 172 is the platform about which the crown 170a or 170b will be built, i.e., the stump to which the crown is attached. Typically, the dental technician then begins to "wax" the RCC and then to sculpt a prepped tooth from the surface of the RCC 172.

In accordance with another aspect of this invention, the system of this invention includes means to facilitate the fabrication of a perfectly prepped tooth. That means comprises in one instance a plastic burn-out sleeve 180 (FIG. 15). This sleeve is arranged to slide over the RCC 172. The burn-out sleeve 180 basically comprises an outside surface 182, a tapered cavity collar 184, an inner bore 186. The bore includes a top opening 188 and a bottom opening 190. The outer surface 182 of the plastic burn-out sleeve 180 is designed to correspond to the dimensions of a naturally prepped tooth. The cavity collar 184 includes a side surface which extends about the entire periphery of the outer surface 182 and forms the lower portion of the cavity 30. This ensures that the crown is created with the same anatomical dimensions that the particular tooth exhibited in the gingiva tissue at that particular location.

The burn-out sleeve 180 is placed on the RCC 172 so that the RCC resides within the bore 186. The technician then secures ("loots") these two pieces together with hot wax.

The tapered cavity collar 184 is selected to be of a sufficient thickness 192 necessary to support the crown 170a or 170b thereon. The collar also should exhibit the proper cusp formation 194 to ensure proper tooth emergence profile with the surrounding gingiva 26. To that end, the collar 184 is in the form of an annular flange extending around the entire periphery of the burn-out sleeve 180. The cavity collar 184 includes a planar top surface which acts as the stop surface or support for both the acrylic temporary crown (cementable type crowns only) and the final metal construction. Among other benefits of proper emergence profile, because the crown bottom 196 fits tightly to the collar 184 with no gaps, the lack of any spaces between the crown 170a (or 170b) and the collar 184 prevents plaque from developing therebetween and eventually destroying the implant 28. On conventional crowns where the bottom surface of the crown 170a (or 170b) does not make a flush interface, any such overhangs will develop plaque, leading to degradation of the implant 28 and gingiva degeneration. Furthermore, the collar 184 is tapered 191 to match the taper 72 or 88 of the unitary members 24 and 74, respectively. Thus, the prepped tooth seats squarely in the cavity 30.

The system of this invention includes another burn-out sleeve for facilitating the prepping of a tooth. This other burn-out sleeve is shown in FIG. 16 and is referred to as a hollow burn-out sleeve 198. In some circumstances where the RCC 172 being used is not compatible with the plastic burn-out sleeve 180 for a particular tooth shape, the hollow burn-out sleeve 198 is used. The hollow burn-out sleeve 198 is constructed so that its outer surface 182 and cavity collar 184 are the same as in the burn-out sleeve 180. However, the inside of the hollow burn-out sleeve 198 is just that, hollow. That is, the burn-out sleeve 198 does not have an inner bore 186. Instead, the burn-out sleeve 198 is a hollow, thin-walled member which is filled with wax. In particular, the sleeve comprises a thin-wall 200 (e.g., 0.5 mm) which is slipped over the top of the RCC 172 so that a gap 202 remains between the RCC 172 and the hollow burn-out sleeve 198. This gap 202 is filled with wax 204 to make the RCC 172 and the hollow burn-out sleeve 198 a solid entity. The hollow burn-out sleeve includes a central hole 188a which serves as the entry port for the wax.

As also shown in FIG. 16, should the RCC 172 selected should be shorter than the hollow burn-out sleeve 198 (or a plastic burn-out sleeve 180) such that the top surface of the RCC 172 does not coincide with the top opening 188 in the hollow burn-out sleeve 198 (or a plastic burn-out sleeve 180), a hollow cylinder 206 is inserted in the central hole 188a. The open central passageway 208 in the hollow cylinder 206 preserves a pathway during the casting procedure (to be described hereinafter) for the passage of the retaining screw 176 at a later time when the crown is secured to the implant.

With the plastic burn-out sleeve 180 or hollow burnout sleeve 198 (and the hollow cylinder 206, if used) secured together, the resulting unit can then be subjected to a casting procedure to create a single metal unit, known as the prepped tooth. The contour of the outer surface 182 and angulations of the burn-out sleeve act to maintain the proper tooth contour during casting. In particular, during the casting procedure the burn-out sleeve 180 burns away and is replaced with metal (i.e., gold, titanium) which takes on the same shape of the burn-out sleeve's outer surface 182.

At this stage, the crown creation varies depending on whether a screw-down type crown or a cementable-type crown is to be created.

If a screw-down type crown is to be made, the technician engages the metal prepped tooth with the implant analog 158 in the anatomical cavity 168 in the stone model 166. Porcelain is then applied directly to the metal prepped tooth to form the crown. The applied porcelain conforms to the anatomical cavity 168 and will have a flat, horizontal bottom surface 196. Because the porcelain conforms to the cavity 168, the crown 170a or 170b will have the proper cusp formation 194. The upper portion, i.e., the portion above the top of the burn-out sleeve of the crown 170a or 170b, is then formed in the natural shape of the tooth. This natural shape is depicted by the broken line in FIGS. 15 and 16. A vertical bore 210 is maintained through the porcelain which aligns with the RCC bore 174. After the porcelain hardens, the entire screw-down type crown is removed from the model 166. The healing cap 20 is then removed from the cavity 30 in the patient's mouth and the screw-down type crown is permanently secured to the implant 28 in the patient's mouth. To that end, the retaining screw 176 is passed down through the bores 210 and 174 and secured into the implant 28. A light curable filler material (not shown) is then poured into the bores 210 and 174 to close off those channels and then cured to set.

If a cementable-type crown is to be made, a plastic temporary crown (not shown) is first made to secure positioning of the emergence tissue 30 created by the healing cap 20 for the loading period (e.g., three to four months) suggested by the dentist before a permanent cementable crown is inserted. This "temporary" crown is necessary for soft-loading the implant 28 in the bone 36. The temporary crown is created by engaging the metal prepped tooth into the anatomical cavity 168 and then pouring an acrylic around the metal prepped tooth and in the cavity 168. The acrylic temporary crown, therefore, has an appropriately shaped outer surface (shown by the broken lines in FIGS. 15 and 16). The inside surface of the temporary crown has a shape corresponding to the prepped tooth that is in the patient's mouth.

The temporary crown is then removed from the prepped tooth and the prepped tooth is removed from the model 166. Next, the metal prepped tooth is secured to the implant 28 in the patient after the healing cap 20 is removed. In particular, the retaining screw 176 is passed down through the bore 174 (and passageway 208, if a hollow cylinder 206 was used in the prepped tooth) to be permanently secured in the central bore 38 of the implant 28. Therefore, there is no need for a bore 210 through the porcelain cementable crown. Cement is then applied to the inside surface of the temporary crown and the temporary crown is then cemented to the metal prepped tooth. The patient is released for the loading period.

After that time has elapsed, the doctor recalls the patient and prepares the permanent cementable crown. To that end, the temporary crown is removed to expose the metal prepped tooth. Another impression (not shown) is then taken of the cavity 30 with the metal prepped tooth in the center of the cavity 30. This is accomplished by syringing impression material around the metal prepped tooth and in the cavity 30. No retraction cord is needed because the cavity has been preserved. The temporary crown is again cemented back to the metal prepped tooth in the patient's mouth until the permanent crown is created. Another stone model, known as a soft tissue model is created. This model has the shape of the anatomical cavity 30 with the metal prepped tooth in the center, and is used to create the permanent cementable crown. The permanent crown has a metal substructure which corresponds to the metal prepped tooth. Porcelain is then applied to the metal substructure in the crown shape. The temporary crown is then removed from the metal prepped tooth and the permanent crown is then permanently cemented on the top of the metal prepped tooth.

It should be noted at this point that the above discussion concerned the creation of a single crown. However, this discussion is by way of example and not limitation and applies to the creation of a bridge (more than a single crown).

To assist the dental laboratory in creating either the cementable or screw-down type of crown using the plastic burn-out sleeves 180/hollow burn-out sleeves 198 and hollow cylinders 206, a laboratory kit (not shown), embodying at least a portion of the system of this invention, can be provided to the dental technicians. This kit may contain plastic burn-out sleeves 180, hollow burn-out sleeves 198, hollow cylinders 206 and healing cap dowels or any other future configurations.

To assist the dental surgeon in preparing the implantation of the dental implant and the insertion of the healing caps 20, a surgery kit (not shown) embodying at least a portion of the system of this invention can be provided for the surgeon. The surgery kit may comprise an entire set of Category I-VII healing caps 20, i.e., unitary members 24 and 74 having either male or female, square, triangular, hexagonal or octagonal anti-rotational couplings, or any other future configuration. There will also be an adequate supply of alignment indicators 140.

It will be important that the surgeon requests a kit corresponding to the type of implants his/her office uses, due to the fact that these kits will need to be stocked with an adequate supply of healing caps 20 and alignment indicators 140. These kits will most likely be made with parts to engage only two different types of implants 28. Because these parts will adequately fit any present or future implant 28 designs, a refill order or purchase order will not be limited to two standard types.

Without further elaboration, the foregoing will so fully illustrate my invention that others may, by applying current or future knowledge, readily adopt the same for use under various conditions of service.