Abstract:
A denture retention system includes a denture and an abutment. The denture has an inner channel with an elastic liner having shaped cavities. The cavities have a shaft, a head at the closed end of the shaft and a concave ring between two convex sections on the shaft. The abutment has a shaft, a head at one end of the shaft, a protruding ring between two concave sections on the shaft and a threaded portion at the other end of the shaft portion. The surface of the cavity overlaps and engages the surface of the abutment to retain the denture in the cavity. The threaded part of the abutment threads into an implant or implants into a jaw. The cavity expands when the abutment is inserted or removed from the cavity, and contracts after insertion.

Description:
[0001]    This application is a continuation-in-part of Ser. No. 12/103,847 filed Apr. 16, 2008. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to dentistry and more particularly to an abutment and system for releasably locating, supporting and retaining a denture. 
       BACKGROUND ART 
       [0003]    Dental implants are used to support one or more artificial teeth. Implants can help support, stabilize and retain full dentures. Suction aids retention of upper full dentures, but suction is generally inadequate for retention of lower full dentures. 
         [0004]    Some prior known implants systems for dentures use a ball shaped abutment that projects from each implant. U.S. Pat. No. 4,787,851 to Kusano, et al. discloses a denture having an inner channel with an elastomeric liner and ball shaped abutments that project into the liner. U.S. Pat. No. 2,112,007 to Adams discloses a denture having an inner channel with snap ring cup sockets and ball shaped abutments that project into the sockets. U.S. Pat. No. 5,049,072 to Lueschen discloses a denture having an inner channel with sockets, O-rings and ball shaped abutments that project into the sockets. 
         [0005]    Other prior known implants systems for dentures use two or more implants with abutments and a bar connecting the abutments. U.S. Pat. No. 5,678,997 to De Buck discloses abutments and a bar connecting the abutments, and a plastic rider connected to a denture that snaps onto the bar. 
       DISCLOSURE OF THE INVENTION 
       [0006]    A denture retention system includes a denture and at least two abutments. The denture has an inner channel with an elastic liner. The abutment has an abutment shaft portion with spaced first and second ends, an abutment head portion at the first end of the abutment shaft portion, a protruding portion between the abutment head portion and the second end of the abutment shaft portion and a threaded portion that projects from the second end of the abutment shaft portion. The abutment shaft portion has first and second concave sections on opposite sides of the abutment protruding portion. A peripheral surface on the abutment head portion has a plurality of flats for engaging a tool to insert the abutment. The abutment head portion has a smooth, convex end surface. The threaded portion can be sized and shaped to thread into an implant or to thread directly into bone as an implant. The liner of the denture has a denture cavity for each abutment. The cavity has a shape complimentary to the shape of the abutment with a cavity shaft portion, a cavity head portion and cavity protruding portion. The cavity surfaces overlap and engage the abutment surfaces to retain the abutment in the cavity. The denture cavity deforms to receive the abutment head portion and the abutment protruding portion. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Details of this invention are described in connection with the accompanying drawings that bear similar reference numerals in which: 
           [0008]      FIG. 1  is a top plan view of a denture retaining system embodying features of the present invention. 
           [0009]      FIG. 2  is a bottom plan view of a denture of the system of  FIG. 1 . 
           [0010]      FIG. 3  is a sectional view of the system of  FIG. 1  taken along line  3 - 3 . 
           [0011]      FIG. 4  is a side elevation view of an abutment of the system of  FIG. 1 . 
           [0012]      FIG. 5  is a top plan view of the abutment of  FIG. 4 . 
           [0013]      FIG. 6  is a bottom plan view of the abutment of  FIG. 4 . 
           [0014]      FIG. 7  is a side elevation view of an implant for the abutment of  FIG. 4 . 
           [0015]      FIG. 8  is a top plan view of the implant of  FIG. 7 . 
           [0016]      FIG. 9  is a side elevation view of another abutment of the system of  FIG. 1 . 
           [0017]      FIG. 10  is a side elevation view of a tool for insertion of the abutment of  FIG. 4  or  9 . 
           [0018]      FIG. 11  is a top plan view of the tool of  FIG. 10 . 
           [0019]      FIG. 12  is a bottom plan view of the tool of  FIG. 10 . 
           [0020]      FIG. 13  is a sectional view of the system of  FIG. 1  taken along line  3 - 3 , with another cavity and another abutment. 
           [0021]      FIG. 14  is a side elevation view of the abutment of  FIG. 13 . 
           [0022]      FIG. 15  is a top plan view of the abutment of  FIG. 14 . 
           [0023]      FIG. 16  is a bottom plan view of the abutment of  FIG. 14 . 
           [0024]      FIG. 17  is a side elevation view of another abutment of the system of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    Referring now to  FIGS. 1 to 3 , a denture retention system  11  includes a denture  14  and abutments  15 . The denture  14  has a body  17  with an outer side  18  and a spaced inner side  19 . The outer side  18  is shaped to simulate the appearance of gums and a plurality of artificial teeth  20  are mounted on the outer side  18 . The inner side  19  has an inner channel  21  that is shaped to receive the gums of a patient. The inner channel  21  includes an elastic liner  23 . The liner is made of an elastomer, a natural or synthetic elastic material. The liner is preferably made of a medical silicone. By way of example, and not as a limitation, the liner  23  can be made of Silastic Type A by Dow-Corning. 
         [0026]    The liner  23  includes a plurality of spaced, shaped denture cavities  24  that extend inwardly from the inner side  19  toward the outer side  18  of the body  17 . The denture cavities  24  are substantially symmetrically positioned relative to the body  17  of the denture  14  and generally two or four denture cavities  24  are provided. Each denture cavity  24  has a cavity shaft portion  26  with spaced first and second ends  27  and  28 , and a cavity head portion  30  at the first end  27  of the cavity shaft portion  26 . The cavity shaft portion  26  is substantially cylindrical. The second end  28  of the cavity shaft portion  26  opens in the direction away from the outer side  18  of the body  17  of the denture  14 . 
         [0027]    The cavity head portion  30  extends radially outwardly relative to the cavity shaft portion  26 , and has a ledge surface  32 , a peripheral surface  33  and an end surface  34 . The ledge surface  32  extends transversely, radially outwardly from the first end  27  of the cavity shaft portion  26 . The peripheral surface  33  extends transversely from the periphery of the ledge surface  32  to the periphery of the end surface  34 . The end surface  34  is preferably concave with a smooth, uninterrupted, low profile dome shape. 
         [0028]    As shown in  FIGS. 4 to 6 , the abutment  15  includes an abutment shaft portion  37  with spaced first and second ends  38  and  39 , an abutment head portion  41  attached to the first end  38  and a threaded portion  42  attached to the second end  39 . The abutment shaft portion  37  is substantially cylindrical and the abutment head portion  41  projects radially outwardly relative to the abutment shaft portion  37 . The abutment head portion  41  has an undercut surface  44  that extends transversely, radially outwardly from the first end  38  of the abutment shaft portion  37 , a peripheral surface  45  that extends transversely from the periphery of the undercut surface  44 , and an end surface  46 , spaced from the undercut surface  44 , that extends radially inwardly from the peripheral surface  45 . The threaded portion  42  is cylindrical with external threads  48  and projects axially from the second end  39  of the abutment shaft portion  37 . 
         [0029]      FIGS. 7 and 8  show an implant  50  having spaced first and second ends  51  and  52 . The first end  51  is flat. The implant  50  has a smooth, cylindrical surface  54  adjacent to the first end  51  and external threads  55  from the cylindrical surface  54  to the second end  52 . A threaded aperture  56  extends into the implant  50  from the first end  51 . The aperture  56  is sized and shaped to receive the threaded portion  42  of the abutment  15 . 
         [0030]    Referring again to  FIG. 3 , the cavity shaft portion  26  is sized to snugly fit around the abutment shaft portion  37 , and the cavity head portion  30  is sized to snugly fit around the abutment head portion  41 . Preferably the liner  23  of the denture  14  is molded around the abutment shaft portion  37  and the abutment head portion  41  of the abutments  15  so the cavity is of a complementary shape with the shape of the head and shaft portions of the abutment. The ledge surface  32  of the cavity head portion  30  retains the undercut surface  44  of the abutment head portion  41 . The elastic liner  23  of the denture  14  stretches to allow removal of the abutments  15  and returns to the original shape after removal. The convex shape of the end surface  46  of the abutment head portion  41  spreads the second end  28  of the cavity shaft portion  26  and aids insertion of the abutment  15  into the denture cavity  24 . 
         [0031]    The threads  55  of the implant  50  thread into the jaw bone structure  57 . The gums  58  extend above the jaw bone structure  57 . The length of abutment shaft portion  37  varies depending upon the height of the gums  58  above the jaw bone structure  57 . 
         [0032]    As shown in  FIGS. 4 to 6 , the peripheral surface  45  of the abutment head portion  41  includes a plurality of flats  59 , for engagement with an insertion tool, described hereinafter. Preferably the peripheral surface  45  of the abutment head portion  41  includes ten to twelve flats  59  instead of the four or six flats on square or hexagon headed bolts. The larger number of flats  59  more closely approximates a circular shape and reduces the possible misalignment of the denture  14  due to misalignment of the peripheral surface  33  of the cavity head portion  30  relative to the peripheral surface  45  of the abutment head portion  41 . 
         [0033]      FIG. 9  shows a modification to the abutment  15  having a threaded portion  60  with external threads  61 . The threaded portion  60  is sized and shaped to thread directly into bone as an implant, replacing the implant  50  described above. This modification is an integral or a one piece body so the abutment and implant is a single piece. 
         [0034]    Referring to  FIGS. 10 to 12 , an insertion tool  63  has a tool head portion  65  and an engagement portion  66 . The tool head portion  65  has the shape of a disk with a round, convex top surface  68 , a knurled peripheral surface  69  that extends transversely from the periphery of the top surface  68  and a flat bottom surface  70  that is spaced from the top surface  68 . A tool aperture  72 , sized and shaped to receive a torque tool, extends into the tool head portion  65  from the center of the top surface  68 . The tool aperture  72  shown has triangular shape. The tool aperture  72  can have other shapes, such as hexagonal to receive an allen wrench or star shaped to receive a torque wrench. The tool  63  may have a hole to receive a string like dental floss that is tied thereto so the tool is not swallowed. 
         [0035]    The engagement portion  66  is a wall that projects from the center of the bottom surface  70  of the tool head portion  65 , and has a circular outer surface  74  and a radially inwardly spaced inner surface  75 . The inner surface  75  has a plurality of flats  76 . The inner surface  75  is sized and shaped to receive and engage the flats  59  of the peripheral surface  45  of the abutment head portion  41  of the abutment  15 . The insertion tool  63  facilitates tightening of the abutment  15 . 
         [0036]    The system  11  provides improved retention over prior known systems without the use of a rigid cup in the denture. Although the system  11  described is directed towards retention of dentures, the abutment  15  can also be used for retention of facial prostheses such as a nose or ear. 
         [0037]      FIG. 13  shows another cavity  79  and another abutment  80  for the denture retention system  11 . The cavity  79  has a cavity shaft portion  82  with a first end  83 , a spaced, open second end  84 , a cavity head portion  86  at the first end  83  of the cavity shaft portion  82 , and a cavity protruding portion  87  on the cavity shaft portion  82  intermediate the cavity head portion  86  and the second end  84 . The cavity head portion  86  and the cavity protruding portion  87  extend radially outwardly relative to the cavity shaft portion  82 . 
         [0038]    The cavity shaft portion  82  has a first convex section  89  between the cavity protruding portion  87  and the second end  84 , and a second convex section  90  between the cavity head portion  86  and cavity protruding portion  87 . The cavity head portion  86  has a peripheral surface  92  and an end surface  93  that connects to the peripheral surface  92  opposite the cavity shaft portion  82 . The end surface  93  is preferably concave with a smooth, uninterrupted, low profile dome shape. The cavity protruding portion  87  has a peripheral surface  94 . 
         [0039]    Referring to  FIGS. 13 to 16 , the abutment  80  includes an abutment shaft portion  97  with spaced first and second ends  98  and  99 , an abutment head portion  101  attached to the first end  98 , an abutment protruding portion  102  intermediate the abutment head portion  101  and the second end  99 , and a threaded portion  103  attached to the second end  99 . The abutment head portion  101  and the abutment protruding portion  102  project radially outwardly relative to the abutment shaft portion  97 . The threaded portion  103  is cylindrical with external threads  104  and projects axially from the second end  99  of the abutment shaft portion  97 . 
         [0040]    The abutment shaft portion  97  has a cylindrical section  105 , first convex section  106  and a second convex section  107 . The cylindrical section  105  extends from the second end  99 . The first convex section  106  curves radially inwardly from the cylindrical section  105  and from the abutment protruding portion  102 , and connects the abutment protruding portion  102  to the cylindrical section  105 . The second convex section  107  curves radially inwardly from the abutment protruding portion  102  and from the abutment head portion  101 , and connects the abutment protruding portion  102  and the abutment head portion  101 . The length of the cylindrical section  105  of the abutment shaft portion  97  varies depending upon the height of the gums  58  above the jaw bone structure  57 . 
         [0041]    The abutment head portion  101  has a peripheral surface  109  and a smooth, convex end surface  110  that extends radially inwardly from the peripheral surface  109 . The peripheral surface  109  of the abutment head portion  101  includes a plurality of flats  111  for engagement by the tool  63 . The peripheral surface  109  of the abutment head portion  101  shown has eight flats. The abutment protruding portion  102  has a substantially cylindrical peripheral surface  112 . 
         [0042]    The cavity head portion  86  is sized to snugly fit around the abutment head portion  101 , and the cavity protruding portion  87  is sized to snugly fit around the abutment protruding portion  102 . The first and second convex sections  89  and  90  of the cavity shaft portion  82  are sized to snugly fit into the first and second concave sections  106  and  107  of the abutment shaft portion  97 . The cavity head portion  86 , cavity protruding portion  87 , the first convex section  89  and the second convex section  90  engage the abutment  80  to retain the abutment  80  in the cavity  79 . The elastic liner  23  of the denture  14  stretches to allow removal of the abutments  80  and returns to the original shape after removal. The convex shape of the end surface  110  of the abutment head portion  101  spreads the second end  84  of the cavity shaft portion  82  and aids insertion of the abutment  80  into the denture cavity  79 . 
         [0043]    The threaded portion  103  of the abutment  80  shown in  FIGS. 13 to 16  is sized to thread into the implant  50  shown in  FIGS. 7 and 8 .  FIG. 17  shows a modification to the abutment  80  having a threaded portion  114  with external threads  115 . The threaded portion  114  is sized and shaped to thread directly into bone as an implant, replacing the implant  50  described above. This modification is an integral or a one piece body so the abutment and implant is a single piece. 
         [0044]    Although the present invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made by way of example and that changes in details of structure may be made without departing from the spirit thereof.