Anatomical restoration dental implant system and healing cap

Abstract: A system and method is provided for implanting tooth analogues in the jawbone resulting in aesthetically and functionally desirable gingival tissue contours after restoration. The system permits modification and adaptation of the tooth analogue to meet intraoral demands in a manner similar to that used in the preparation and restoration of natural teeth. The system comprises a standard fixture (12) and cover screw passed through opened gingival tissue and implanted in the jawbone. After the ossointegration of the fixture, the gingiva is reopened, the cover screw removed and a healing cap (30) having a predetermined contour, is attached to the fixture. The reopened gingiva re-heals in a shape determined by the contour of the healing cap. The healing cap is then removed and replaced by an abutment (4,6,9) having an emergence profile matching that of the healing cap. An immediate snug fit between the gingival tissues and the abutment is thereby provided at the time of connection of the abutment to the fixture. A crown (2) is removably attached to the abutment by a screw (90) extending through the side of the crown into the abutment. An improved version of the healing cap is a healing cap created in two portions (138,140) so that one portion (138) around which gingiva tissue regrows remains in the patient and only a second upper portion is removed (140), and an improved abutment (204) which is engagable with the portion of the healing cap left in the patient is used for the abutment about which the crown is removably attached.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to the field of dental implants and in particular to a system providing a tooth analogue and a gingival tissue healing cap which results in a restoration having tissue-implant profiles similar to that of a natural tooth and its surrounding gingiva. The present invention also relates to fitting a tooth with a temporary crown and final prosthesis after the initial implant structure has been inserted and the surrounding tissue has healed. A dental implant system as well as a healing cap as specified in the preamble of Claims 1 and 24, respectively are disclosed in EP-A-0 139 052. 2. Description Of The Prior Art Many systems have been proposed for rigidly fixing metal or ceramic materials to the alveolus of a human mandible or maxilla in an effort to provide a long term replacement for lost teeth. Early systems were successful for only limited periods of time and were eventually rejected as foreign bodies. Later systems, as described by U.S. Patents Nos.3,589,011 to Sneer, 3,797,113 to Brainin, 3,979,828 to Taylor, 4,324,550 to Reuther et al., and 4416629 to Mozsary et al., have proven to offer long term success by providing rigid anchorage in the supporting bone. Intraoral restoration of such ossointegrated devices has been accomplished with many different systems that modified the original attempts. Such modifications have been described in U.S. Patents Nos. 4,780,080 to Harras, 4,713,003 to Symington et al., and 4,657,510 to Gittleman. However, these restorative systems have aesthetic compromises. The interface between an implant and its surrounding gingival tissue is often insufficiently close to prevent food and bacteria from entering this area. Such foreign matter can cause chronic infection and bone loss, resulting in eventual loss of the implant. Implants in current use have a round root form dimensionally different from that of a normal tooth root morphology. This makes aesthetic restoration difficult, impedes the development of a natural soft gingival tissue contour and detracts from the appearance of the user. European Patent Application Number EP-A-0,139,052 discloses a dental implant system including a tooth root and a post for supporting an artificial tooth in a jaw bone. The tooth root is implanted into the jaw bone, and the post is turned into a threaded hollow in the tooth root. German Offenlegungsschrift Number DE-A-3,739,434 discloses a dental implant system including a fixture and an abutment for supporting an artificial tooth in a jaw bone. The abutment is turned into a threaded hollow in the fixture. There exists a need for a dental implant system providing an implant root and gingival tissue interface having an improved resistance to bacterial infection and providing a contour more nearly approximating that of a natural tooth and its surrounding tissue, so that the appearance of a user of the implant is improved. In addition, removal of the transepithelial sleeve and/or healing caps to fit a temporary crown and then a permanent crown requires removal of the entire abutment/or healing cap structure which causes damage to the surrounding tissue including apical migration of the tissue and in turn necessitates additional healing time. There exists a further need for a dental implant system which permits a temporary crown and then a permanent crown to be fitted and implanted without requiring that the temporary abutment and/or healing caps be removed. SUMMARY OF THE PRESENT INVENTION In one aspect, the invention herein may be summarized as: a dental implant system implantable in the gingival tissue and the alveolus of the jaw bone for supporting a tooth analogue, as claimed in claim 1 herein. In another aspect, the invention is a healing cap for use with an implantable fixture having an open end and a threaded hollow, as claimed in claim 12 herein. The invention provides a system such that the emergence profile of the analogue more closely matches that of a natural root and the system provides a tight fit between the analogue and the gingiva upon installation of a crown or other tooth replacement. The system comprises an implantable fixture having proximal and distal end portions, the proximal end portion having means for being implanted through opened gingival tissue into the alveolus of the jaw bone, the distal end portion being accessible from the outer surface of the jaw bone. The fixture contains a hollow interior beginning with an opening in the distal end portion and extending towards the proximal end portion. The hollow has threads along at least a portion of its length. The invention utilizes a cover screw for sealing the hollow portion of the fixture during the time the jaw bone is growing about the fixture. After ossointegration of the fixture, the gingiva is reopened and the cover screw is removed and replaced by a healing cap. Having the same contour permits the abutment to tightly fit the healed opening in the gingival tissue upon engagement of the abutment with the fixture. The abutment is removably affixed to the fixture by a screw having a threaded end portion and a driven end portion. The threaded end portion is passed through the abutment and threaded in the hollow of the fixture. The driven end portion of the screw is co-operable with a driving tool, such as a screwdriver and engages the abutment, holding the abutment in place against the fixture. In a presently preferred embodiment, the abutment comprises a divergent segment and a head segment, the segments both having a frusto-conical shape. The smaller end of the divergent segment engages distal end portion of the fixture, while the larger end of the divergent segment is attached to the smaller end of the head segment. The smaller end of the head segment being smaller than the larger end of the divergent segment creates a shoulder at their juncture. The axis of the divergent and head segments are in alignment with the axis of the fiture. The system additionally comprises a tooth analogue releasably engageable with the abutment. In a presently preferred embodiment the analogue comprises a crown having a hollow interior adapted to fit on the head section of the abutment. The crown additionally has an opening extending laterally through the sidewall thereof. The opening is alignable with the threaded hollow in the side of the abutment. A holding screw secures the crown to the abutment. The screw has a threaded end portion and a driven end portion. The threaded end portion is passed through the opening in the side of the crown and is threaded in the opening in the side of the abutment. The driven end portion cooperable with a driving tool and is engagable within a recess int he sidewall of the crown. With the exception of the crown, all elements of the invention are made of titanium or other rigid substance, compatible with implantation within the body. The present invention also comprises an improved healing cap and an improved abutment for use in conjunction with the improved healing cap. Instead of being made of one piece construction, the improved healing cap is made of two piece construction. A first part includes a divergent or frusto-conical segment having the desired shape for the gingiva to heal around so that the gingival tissue heals in a contour reverse to the contour of the divergent segment. The second part includes a cylindrical portion having a threaded stem which permits removable engagement with the first part through a threaded hollow in the adjoining end of the divergent segment, and a driven part or screw-head in the second part joined to the cylindrical segment. During the healing, the second part is removed from the first part which remains in the patient so that the healing of the gingiva is not disturbed. The improved abutment comprises a frusto-conical shaped head segment with a threaded stem extending form the large end of the head segment and engagable with the threaded hollow in the frusto-conical segment of the sealing cap which remains in the patient. The tooth analogue is releasably engagable with the abutment. The foregoing and other advantageous and distinguishing features of the invention are described in detail below and are recited in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Referring particularly to the drawings for the purpose of illustration only and not limitation, there is illustrated: FIG. 1 is a sectional view of a healing cap and fixture of a presently preferred embodiment of the invention showing a portion of the jawbone and gingiva in a broken away configuration. FIG. 2 is a sectional view of a crown, abutment, fixture and holding screws of the presently preferred embodiment of the invention showing a portion of the jawbone and gingiva in a broken away configuration. FIG. 3-6 are side elevation views of preferred healing caps of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Although specific embodiments of the invention will now be described with reference to the drawings, it should be understood that such embodiments are by way of example only and merely illustrative of but a small number of the many possible specific embodiments which can represent applications of the principles of the invention. Various changes and modifications obvious to one skilled in the art to which the invention pertains are deemed to be within the scope and contemplation of the invention as further defined in the appended claims. Referring now to FIGS. 1 & 2, the present invention is a system of providing a tooth analogue for one or more missing teeth. The tooth analogue may comprise a crown, a fixed or removable partial denture, or a fixed or removable full denture. In a presently preferred embodiment of the invention the analogue comprises a crown 2 removably affixed to an abutment 4. According to the preferred method of installing the analogue in the mouth of a patient, a socket is prepared in the alveolus of the jawbone where a tooth has been extracted or otherwise lost. A conventional fixture 12 is implanted in this area. An exemplary fixture is roughly cylindrical in shape and possesses a threaded surface 14. The fixture 12 includes a hollow portion 18 which extends from the upper surface 20 of the fixture toward the lower surface 22 thereof. The fixture is implanted such that the distal end portion 24 of the fixture extends to the outer surface of the jaw bone 26. The proximal end portion 28 of the fixture extends into the jaw bone 26 as far as is necessary for a satisfactory implantation. In one embodiment, the jawbone is drilled and threaded in preparation for receiving the fixture. During implantation, the threaded surface 14 of the fixture 12 threadingly engages the threaded surface 29 of the jaw bone 26. After implantation of the fixture 12, a cover screw is threaded into the fixture (not shown) to seal it during the period in which bone is growing about the proximal portion 28 of the fixture. The gingival tissue 37 above the fixture is closed according to procedures well known in the art. Upon completion of ossointegration of the fixture 12, the gingival tissue 37 above the fixture is reopened and the cover screw is removed. The healing cap 30 is then threaded into the fixture and held in place by a stem 31. The stem has a distal end portion 32, and a proximal end portion 33, which together have a threaded surface 34. The threaded surface 34 is engaged with a threaded surface 36 within the hollow portion 18 of the fixture to hold the healing cap 30 in place. The fixture 12 has a raised lip 21 around the opening of the hollow 18 in the distal end portion 24 of the fixture. The lip 21 may be circular or hexagonal in shape. The lip fits within an appropriately configured socket 39 of the healing cap 30. The engagement of the lip within the socket provides additional support to the engagement of the healing cap 30 to the fixture 12. The healing cap 30 is additionally configured to allow the gingival tissues 37, surgically displaced during removal of the cover screw to heal around the cap in a shape which is dimensionally similar to the tooth previously removed or lost. The proper contouring of the gingival tissues 37 during their healing is necessary to assure a tight fit between the abutment and the gingiva. This tight fit provides improved esthetics for the completed restoration. Referring additionally now to FIGS. 3-6, preferred healing caps 30 may be configured in differing diameters, heights and emergence profiles to permit the gingival tissues 37 to be guided in healing to a proper form, commensurate with that desired at the completion of the restoration. Details of three section healing caps 30 are shown in FIGS. 3 & 4. The caps have a frusto-conical section 38, the smaller end 35 of which is attached to the distal end 32 of the stem 31. A cylindrical section 40 extends away from the frusto-conical section 38, having a proximal end 42 attached to the larger end 43 of the frusto-conical section. A screw head segment 46 terminates the healing cap 30, having a proximal end 48 which is attached to the distal end 44 of the cylindrical section 40. The screw head segment 46 also has a driven end 49 co-operable with a driving tool. The driven end is preferably a slot 51 transverse to the long axis of the healing cap 30, which may be driven by a blade screwdriver. Four section healing caps 50 are shown in FIGS. 5 & 6. These caps have the same elements as the three section caps 30 with the addition of a cylindrical shaped base 52. The base 52 is used to fill the space between the surface of the jaw bone and the distal portion 24 of the fixture 12 when the surface of the jaw bone, after healing about the fixture, extends above the distal portion of the fixture. The base 52 has a proximal end portion 54 and a distal end portion 56. The proximal end portion 54 is attached to the distal end portion 32 of the stem 31, and the distal end portion 56 is attached to the smaller end 35 of the frusto-conical section. The long axes of the segments 38, 40, 46, 52 and the stem 31 of the healing caps 30, 50 are preferably aligned. At the juncture of the segments 52, 38, 40 & 46, the circumference of each segment is preferably the same as that of each adjoining segment. The healing caps 30 & 50 are preferably made of a one piece construction. After placement of the fixture 12 in the jaw bone 26 and a healing cap 30 or 50 through the gingival tissue 37, the gingiva is sutured about the cap. The fixture and cap are permitted to remain in place until a tooth analogue has been made and is ready for insertion into the fixture. This requires a period of eight weeks or longer. When the tooth analogue is ready for insertion the cap is removed from the fixture 12 and replaced with a tooth analogue including an abutment 4. Referring again to FIG. 2, the abutment 4 is secured to the fixture 12 by a screw 60 having a threaded end portion 61 and a driven end portion 62. The screw is passed through the abutment hollow 10 and engaged with the threaded surface 36 within the fixture 12. The driven end portion 62 of the screw 60 is preferably a slot 66, transverse to the long axis of the screw, which is co-operable with a blade screwdriver. A feature of the use of a screw 60 to secure the abutment 4 to the fixture 12 is that the divergent segment 68 can be prepared in the same manner as a natural tooth, with reduction of the occlusal, and proximal surfaces of the abutment as necessitated by the situation. Additionally, axial reduction of the abutment may be performed to facilitate fabricating anatomically correct restorations. Axial reduction also permits separation from adjacent teeth or implants, and varying cervical contours as required for tissue health and aesthetic appearance. Referring again to FIG. 2, the crown 2 is comprised of elements well known in the dental arts. The crown 2 has a hollow interior 88 adapted to fit on the head 70 of the abutment 4. The crown 2 may be releasably attached to the abutment by a dental crown adhesive or by a screw. When the screw attachment method is used, a screw 90 is passed through an aperture 91 in the side of the crown. The abutment 4 has a threaded hollow 92 in its sidewall extending into the hollow 10 of the abutment. The screw 90 comprises a threaded end portion 94 and a driven end portion 96. The screw is passed through the aperture 91 and the threaded end portion 94 is engaged in the threaded hollow 92. The side of the crown additionally has a recess 98 which receives the driven end portion 96. With the exception of the crown 2, all elements of the invention are preferably fabricated of pure titanium, but may be made of other biocompatible materials. The dental implant system of the present invention provides for development of proper gingival tissue form resulting in more aesthetically and functionally desirable tissue contours at the time of and following tooth analogue connection. The system also allows modification and adaptation of the abutment 4 to meet intraoral demands in a manner similar to that used in the preparation and restoration of natural teeth. In view of the foregoing description of the invention in accordance with the requirements of the patent statutes, those skilled in the relevant arts will have no difficulties making changes and modifications in the different described elements of the invention in order to meet their specific requirements or conditions. For example, those elements having a driven end may comprise a socket co-operable with an allen wrench. Multiple as well as single restorations may be accomplished. Fixed full or partial dentures or removable prostheses may constitute the tooth analogues. Such changes and modifications may be made with out departing from the scope of the present invention. In operation, the fixture 12 remains in the jawbone 26 and the healing cap 30 or 50 is threaded into the fixture and held in place by stem 31. As previously described, the threaded surface 34 of stem 31 is engaged with the threaded surface 36 within the hollow portion 18 of fixture 12 to hold the healing cap 30 or 50 in place. The gingival tissues 37 are then given time (usually at least eight weeks) to heel around the healing cap 30 or 50. The proper contouring of the gingival tissues 37 during their healing is necessary to assure a tight fit between the abutment and the gingiva. During this time, ossointegration of the fixture 12 to the jawbone 26 also takes place. When the time is ready to test fit a crown 2, which initially is a temporary crown and subsequently a permanent crown, it is necessary to entirely remove the healing cap 30 or 50 and replace it with the abutment 4 in the manner previously described. By this time, the regrown gingival tissues 37 have conformed to the shape of the frustoconical section 38 of healing cap 30 or 50. Therefore, when the healing cap 30 or 50 is removed, at least some damage such as bruising and possibly some tissue removal is imparted to the regrown portion of gingival tissues 37 adjacent the frusto-conical section 38. Therefore, after the temporary crown is fitted, it is necessary to once again reinsert the healing cap 30 or 50 and the gingival tissues 37 must again be given time to regrow. Due to the bruising or tissue removal, the gingival tissues 37 may not properly regrow in the manner originally formed against the frusto-conical section 38. This results in a delay of several additional weeks. In addition, this procedure must be repeated if it is necessary to refit the temporary crown and further must be repeated when it is time to fit the permanent crown. Therefore, an improvement is required wherein at least the frusto-conical portion 38 of healing cap 30 or 50 remains threaded into the jaw 26 and the frustoconical portion 38 remains in its position within the regrown gingival tissues 37, thereby substantially reducing the trauma caused to the gingival tissues 37 when the temporary crown and later the permanent crown is fitted. An improved healing cap 130 and mating abutment member is illustrated in FIGS. 7 through 10. As with the healing caps illustrated in FIGS. 3 through 6, the improved healing cap 130 may be configured in differing diameters, heights and emergence profiles to permit the gingival tissues 37 to be guided in healing to a proper form, commensurate with that desired at the completion of the restoration. In addition, although the improved healing cap 130 is illustrated as a three section cap comparable to the healing caps illustrated in FIGS. 3 and 4, it can also be composed in the form of the four section healing caps illustrated in FIGS. 5 and 6 with the addition of a cylindrical shaped base beneath the frusto-conical section. The critical feature of novelty in the improved healing cap 130, regardless of whether it is a three section healing cap comparable to those illustrated in FIGS. 3 and 4 or a four section healing cap comparable those illustrated in FIGS. 5 and 6, is that instead of being of one piece construction which is the design of all four healing caps in FIGS. 3 through 6, the improved healing cap is made of two piece construction. Of course the present invention is not intended to be restricted to any particular form or arrangement, or any specific embodiment disclosed herein, or any specific use, since the same may be modified in various particulars or relations without departing from the scope of the claimed invention hereinabove shown and described of which the apparatus is intended only for illustration and or disclosure of an operative embodiment and not to show all of the various forms of modification in which the invention might be embodied or operated. The invention has been described in considerable detail in order to comply with the patent laws by providing full public disclosure of at least one of its forms. However, such detailed description is not intended in any way to limit the broad features or principles of the invention or the scope of patent monopoly to be granted.

Claims: A dental implant system implantable in the gingival tissue (37) and the alveolus of the jaw bone (26) for supporting a tooth analogue (2), the system having: (a) an implantable fixture (12) having a proximal end portion (28) and a distal end portion (24), the proximal end portion (28) having means for being embedded in opened gingival tissue (37) and the alveolus of the jaw bone (26), the distal end portion (24) being accessible from the outer surface of the jaw bone (26), the fixture (12) being made of a substance permitting healing of the opened gingival tissue (37) and growth of the jaw bone (26) about the fixture (12), the fixture (12) further including a hollow (18) extending from an opening in the distal end portion (24) towards the proximal end portion (28), the hollow (18) having threads (36) along at least a portion of its length; (b) means for sealing the hollow (18) of the fixture (12) during a period after implantation in which the jaw bone (26) is growing about the proximal end portion (28) of the fixture (12); (c) means (30) for providing a predetermined contour to the gingival tissue (37) adjacent the distal end portion (24) of the fixture (12), such that the gingival tissue (37) reheals in a contour reverse to that of the contour of the means (30); (d) said contour means (30) being a healing cap having: (e) a stem (31) having a proximal end portion (33) and a distal end (32), the proximal portion (33) being threadable within the hollow (18) of the implantable fixture (12); (f) a segment (38), one end (35) of the segment (38) being attached to the distal end (32) of the stem (31), with the axis of the segment (38) being in alignment with the axis of the stem (31); (g) a cylindrical segment (40) having a proximal end (42) and a distal end (44), the proximal end (42) being attached to the other end (43) of the segment (38), with the axis of the cylindrical segment (40) being in alignment with the axis of the segment (38); and (h) a screw head segment (46) having a proximal end (48) and a driven end (49), the driven end (49) co-operable with a driving tool, the proximal end (48) being attached to the distal end (44) of the cylindrical segment (40), with the axis of the screw head segment (46) being in alignment with the axis of the segment (38); (i) abutment means (4) for supporting the tooth analogue (2) engagable with the implantable fixture (12), said abutment means (4) having the same contour as the fixture sealing and gingival tissue contouring means (30) in the area to be placed in contact with the gingival tissue (37) such that the abutment means (4) makes a tight fit with the healed gingival tissue (37) adjacent the distal end portion (28) of the fixture (12); and (j) means (90) for releasably attaching the tooth analogue (2) to the abutment means (4); characterized in that (i) said segment (38) is a frusto-conical segment, said one end of said segment is a smaller end (35) of the segment (38), and (ii) said other end of the segment (38) is a larger end (43) of the frusto-conical segment (38). The dental implant system of Claim 1 further characterized in that the tooth analogue (2) has a crown (2) having a hollow interior adapted to fit on a portion of the abutment means (4). The dental implant system of Claim 1 or 2 further characterized in that said healing cap additionally has a base (52), the base (52) having a cylindrical shape with a proximal end (54) and a distal end (56), the proximal end (54) of the base (52) being attached to the distal end (32) of the stem (31), and the distal end (56) of the base (52) being attached to the smaller end (35) of said frusto-conical segment (38), with the axis of the base (52) being in alignment with the axes of said stem (31) and said frustoconical segment (38). The dental implant system of any preceding Claim further characterized in that the exterior of the sidewall (84) of said frusto-conical segment (38) of said healing cap extends outward from the smaller end (35) of the segment (38) at an angle of between 45 degrees and 65 degrees to the axis of the segment (38). The dental implant system of any preceding Claim further characterized in that at the juncture between said screw head segment (46) and said cylindrical segment (40) of said healing cap, the circumference of said cylindrical segment (40) is the same as the circumference of said screw head segment (46). The dental implant system of any preceding Claim further characterized in that at the juncture between said cylindrical segment (40) and said frusto-conical segment (38) of said healing cap, the circumference of said cylindrical segment (40) is the same as the circumference of said frusto-conical segment (38). The dental implant system of Claim 1 further characterized in that the abutment means (4) comprises a hollow abutment device and a screw (60), the screw having a threaded end portion (61) and a driven end portion (62), the threaded end portion (61) passable through the abutment device and threaded in the hollow (18) of the implantable fixture (12), the driven end portion co-operable with a driving tool and engagable with the abutment device. The dental implant system of Claim 7 further characterized in that said abutment device of said abutment means (4) has: a. a divergent segment (68) having a hollow frusto-conical shape, the smaller end of the segment being engagable with the distal end portion (24) of the implantable fixture (12), with the axis of the segment (68) being in alignment with the axis of the fixture (12); and b. a head segment (70) having a hollow frusto-conical shape, the larger end of the head segment (70) being attached to the larger end of the divergent segment (68), with the axis of the head segment (70) being in alignment with the axis of the divergent segment (68), and the larger end of the divergent segment (68) being larger than the larger end of the head segment (70), thereby creating a shoulder at their juncture. The dental implant system of Claim 8 further characterized in that the exterior of the sidewall of said divergent segment (68) extends outward from the smaller end of the segment (68) at an angle of between 45 degrees and 65 degrees to the axis of the segment (68). The dental implant system of Claim 1 further characterized in that the means for releasably attaching said tooth analogue (2) to the abutment (4) include an adhesive. The dental implant system of Claim 2 further characterized in that the means for releasably attaching the crown (2) to the abutment (4) has: a. a threaded hollow (92) in the side of the abutment means (4); b. an opening (91) extending laterally through the side of the crown (2), the crown (2) opening (91) alignable with the threaded hollow (92) in the side of the abutment means (4); and c. a holding screw (90) having a threaded end portion (94) and a driven end portion (96), the threaded end portion (94) passing through the opening (91) in the side of the crown (2) and threaded in the opening (92) in the side of the abutment (4), the driven end portion (96) co-operable with a driving tool and engagable with the crown (2). A healing cap for use with an implantable fixture (12) having an open end (24) and a threaded hollow (18), the healing cap having: a screw head segment (46) having a proximal end (48) and a driven end (49), the driven end (49) being cooperable with a driving tool; a stem (31) having a proximal end portion (33) and a distal end (32), the proximal end portion (33) being threadable within the hollow (18) of the implantable fixture (12), said cap being characterized by: a divergent segment (38) having a frusto-conical shape, the smaller end (35) of the segment (38) being attached to the distal end (32) of the stem (31) with the axis of the segment (38) being in alignment with the axis of the stem (31), wherein the stem (31) seals said fixture (12); and a cylindrical segment (40) having a proximal end (42) and a distal end (44), the proximal end (42) of said cylindrical segment (40) is attached to the larger end (43) of the frusto-conical segment (38) with the axis of the cylindrical segment (40) being in alignment with the axis of the divergent segment (38), and the axis of the screw head segment (46) is in alignment with the axis of the divergent segment (38). The healing cap of Claim 12 further characterized by a base (52), the base (52) having a cylindrical shape with a proximal end (54) and a distal end (56), the proximal end (54) of the base (52) being attached to the distal end (32) of the stem (31), and the distal end (56) of the base (52) being attached to the smaller end (35) of said divergent segment (38), with the axis of the base (52) being in alignment with the axes of said stem (31) and said divergent segment (38). The healing cap of Claim 12 or 13 further characterized in that the exterior of the sidewall (84) of said divergent segment (38) of said healing cap extends outward from the smaller end (35) of the segment (38) at an angle of between 45 degrees and 65 degrees to the axis of the segment (38). The healing cap of Claim 12 or 13 further characterized in that at the juncture between said screw head segment (46) and said cylindrical segment (40) of said healing cap, the circumference of said cylindrical segment (40) is the same as the circumference of said screw head segment (46). The healing cap of Claim 12 or 13 further characterized in that at the juncture of the elements, the circumference of each element, excepting the stem (31), is the same as that of each adjoining element.

Inventors: DAFTARY FEREIDOUN, DAFTARY, FEREIDOUN
Applicants: DAFTARY FEREIDOUN, DAFTARY, FEREIDOUN
Application year: 1990
Main classification: A61C8
IPC codes: A61C8