Abstract:
A dental prosthesis apparatus, comprising at least a pair of implants for selective imbedding in maxillary bone structure and each having an angle-adjusting abutments to which a rail clip assembly attaches, each rail clip assembly holding a portion of a rail between a lower rail clip and an upper rail clip, the rail and clip assemblies connected together, for seating of a denture to the abutments. A method of fabricating a dental prosthesis is disclosed.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to dental prosthesis and fabrication. More particularly, the present invention relates to dental prosthesis readily fabricated chair side of a patient. 
       BACKGROUND OF THE INVENTION 
       [0002]    In recent years, dental implants have become a viable option for both partial and full prosthesis whereby a missing tooth, or multiple missing teeth, are replaced with an artificial fabricated substitute. There are at least several manufacturers providing dental prosthesis devices. The dental prosthesis technology uses implants that seat in bone structure of the jaw, and a variety of secondary connections referred to as abutments attach rigidly to the implants. Bridges attach to the abutments, and restorative teeth attach in spaced-relation to the bridges. 
         [0003]    Generally, a dental surgeon places the implants within bone. The implant location is selected to facilitate acceptance of the implant by bone structure while avoiding weak bone sections, nerves, and sinus cavities. The implants may be disposed at oblique angles in order to seat a longer implant while forming strong implant-to-bone connections. The implants integrate with the bone through bone growth, typically over a several month period. The implants become a foundation that supports the bridges and restorations. An abutment is selected from a variety of abutments having differing characteristics (length, angle, cross-sectional width). The abutment attaches rigidly to the implant for alignment of the bridge. 
         [0004]    The abutments are installed upon satisfactory seating of the implant within the bone. Because implant positions are limited to locations of good bone, the abutments provide a gross adjustment of misaligned or off-axis direction of placement of the implant. Multiple implants may be connected together, or splinted, for cross-arch stabilization during the integration process, such as attaching a temporary prosthesis prior to full integration. 
         [0005]    A temporary prosthesis, or bridge of teeth, is fabricated for use during integration. The temporary prosthesis is typically made of acrylic, for short term use, as such material is subject to fracture. Thus, temporary prosthesis may not allow for full occlusion whereby the patient may chew food properly. 
         [0006]    Upon satisfactory healing of the implant/bone root form, the patient is attended by a prosthodontist for fabrication of a permanent prosthesis. The healing process may be several or more months. With implant/bone integration, an impression is formed of the patient&#39;s maxillary structure. The impression is used by a laboratory for fabrication of a rigid framework to support the denture or bridge of teeth. Traditional casting may be used to form the denture, or more recently, digital scanning and CAD/CAM technology may be used. This latter technology features milling a titanium block to form a unique framework. This is specialized machining and there are a limited number of experienced product providers. The labor is time consuming and materials expensive. Once the temporary bridge is replaced with the permanent bridge, the patient is provided with an excellent prosthesis. 
         [0007]    However, there are drawbacks limiting the desirability of such permanent prosthesis. Should an implant fail, or move, the milled bar must be completely discarded. The fabrication process recommences with the impression/scanning/milling process repeated. The milled parts are not retrievable for re-use. Generally, the process is time consuming. The time required may span from several months to years for the final permanent prosthesis to be installed. Further, the process requires services of multiple professionals working at various locations remote from each other. As an alternative, a technical company has attempted to shorten the time required by housing the three required professional (surgeon, prosthodontist and dental laboratory technician) in a single complex. 
         [0008]    Further, there are drawbacks with these systems for fabrication of prosthesis. The support bars need to be horizontal. Due to positioning variances and angular alignment of the implants, each abutment requires separate height alignment. Further, the abutments require different angular alignment in order to orient the support member vertical for engaging the denture. The present systems further do not readily permit fabrication of the front retaining bar that aligns with the parabolic-shaped dental arch. The rigid assembly of the denture is not removable during fabrication. Also, in the event of moving of the implant, the components used in the denture are lost because of the special design configured for the particular position of the implant. Components are not retrievable and reusable in the event of movement of an implant. Also, the implants provide point-to-point support for the prosthesis and are unsatisfactory for including a cantilever extended portion so as to enlarge the occlusal chewing surface. 
         [0009]    Accordingly, there is a need in the art for an improved prosthesis apparatus and method of fabrication. It is to such that the present invention is directed. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention meets the need in the art by providing a dental prosthesis apparatus, comprising at least a pair of implants, each implant for selective imbedding in a maxillary bone structure and defining a threaded axial bore, and a pair of abutments, each seated on a respective one of the implants and defining an axial passageway therethrough and defining a second threaded bore therein. A pair of screws, each one extending through the passageway of a respective abutment and engaging the threaded bore of the implant for securing the abutment to the implant. At least a pair of rail assemblies, with each rail assembly attached to a respective one of the abutments. Each rail assembly comprising a spacing member having a threaded first end and defining a longitudinally extending passageway therethrough, a first rail clip disposed at the first end of the spacing member, a second rail clip disposed on a second end of the spacing member, and a fastener connected to the second end of the spacing member for securing the first rail clip and the second rail clip in spaced relation. A threaded member extending through the spacing member and engaging the second threaded bore in the respective abutment for securing the rail assembly to the abutment. A rail extending between the pair of rail assemblies and disposed with a respective portion between the first rail clip and the second rail clip of each of the rail assemblies, whereby the rail assembly, being secured with the threaded member connected to the abutment, rigidly holds the rail between the first rail clip and the second rail clip. 
         [0011]    In another aspect, the present invention provides a dental prosthesis apparatus comprising at least a pair of implant members for selective imbedding of each in a maxillary bone structure of a patient. The implant member defines a seating surface to which a respective one of at least a pair of rail assemblies attaches. Each rail assembly comprises a first rail clip and a second rail clip disposed in opposing spaced relation; and a fastener for engaging the seating surface of the implant member and holding the first and second rail clips in spaced relation. A rail extends between the pair of rail assemblies and is disposed with a respective portion between the first rail clip and the second rail clip of each of the rail assemblies. Each of the rail assemblies, being secured with the fastener to the seating surface, rigidly holds the rail between the respective first rail clip and the second rail clip. 
         [0012]    In another aspect, the present invention comprises a method of securing a dental prosthesis rail to an implant received in bone, the implant having an abutment secured thereto, the abutment defining a threaded bore therein, comprising the steps of: 
         [0013]    (a) providing a lower clip and an opposing upper clip spaced apart by a spacing member and disposing a portion of a rail therebetween; 
         [0014]    (b) securing the lower clip and the upper clip together as an assembly to rigidly hold the rail therebetween; and 
         [0015]    (c) attaching the assembly of the lower clip and the upper clip to the abutment. 
         [0016]    In yet another aspect, the present invention comprises a method of securing a dental prosthesis, comprising the steps of: 
         [0017]    (a) imbedding at least a pair of implant members into a maxillary bone structure of a patient in spaced-apart relation, each of the implant members defining a seating surface; 
         [0018]    (b) attaching a pair of rail assemblies, each rail assembly attached to a respective one of the implant members, each rail assembly comprising:
       a first rail clip and a second rail clip disposed in opposing spaced relation; and   a fastener for engaging the seating surface of the implant member and holding the first and second rail clips in spaced relation;       
 
         [0021]    (c) disposing a rail longitudinally between the pair of rail assemblies with a respective portion between the first rail clip and the second rail clip of each of the rail assemblies, 
         [0022]    whereby each of the rail assemblies, being secured with the fastener to the seating surface, rigidly holds the rail between the respective first rail clip and the second rail clip. 
         [0023]    Objects, advantages, and features of the present invention will become readily apparent upon a reading of the detailed description in reference to the drawings and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  illustrates a full arch assembly of a dental prosthesis in accordance with the present invention. 
           [0025]      FIG. 2  is an exploded view of a prosthesis apparatus used in the dental prosthesis illustrated in  FIG. 1 . 
           [0026]      FIG. 3  is a detailed prospective view of an upper rail clip used in the illustrated embodiment of the dental prosthesis shown in  FIG. 1 . 
           [0027]      FIG. 4  is a detailed respective view of a lower rail clip and spacer column used in the illustrated embodiment of the dental prosthesis shown in  FIG. 1 . 
           [0028]      FIG. 5  is a prospective view of a rail member for being received by the lower rail clip and the upper rail clip shown in  FIGS. 3 and 4  for the dental prosthesis shown in  FIG. 1 . 
           [0029]      FIG. 6  is a prospective exploded view of an alternate embodiment of a rail for use in a dental prosthesis in accordance with the present invention. 
           [0030]      FIG. 7  illustrates a denture molded of a conventional material with a plurality of teeth for containing the prosthesis apparatus illustrated in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    With reference to the drawings, in which like parts have like identifiers,  FIG. 1  illustrates a full arch assembly of a dental prosthesis  10  in accordance with the present invention. The prosthesis  10  in the illustrated embodiment includes four implant assemblies  12  and a rail  14  that defines a parabolic-shaped dental arch portion  16  and opposing extending posterior arch portions  17 ,  18 . In the illustrated embodiment, a portion  19  of the rail  14  extends as a cantilever longitudinally posterior of a posterior implant assembly  12   b.    
         [0032]    With reference to  FIGS. 1 and 2 , each implant assembly  12  includes a dental implant  20 , an abutment  22 , and a clip assembly  24  (shown in detailed exploded view in  FIG. 2 ). The clip assembly  24  secures the rail  14  to the abutment  22  of the implant  20 . The implant  20  and the abutment  22  are conventional members provided by dental prosthesis providers. The implant  20  seats in a bone structure of a patient for the dental prosthesis  10 . The implant  20  defines an internal threaded bore  21 . The abutment  22  defines a first passageway  23 . The abutment  22  seats on the upper end of the implant  20 . An abutment screw  26  extends through the passageway  23  and threadably engages the threaded bore  21  of the implant  20 . The screw  26  thereby secures the abutment  22  to the implant  20 . 
         [0033]    The abutment  22  further defines a second threaded bore  28 . The bore  28  is oriented at an angle within the abutment, so that upon connection of the abutment  22  to the implant, the bore  28  is disposed at a substantially vertical orientation (±5°). 
         [0034]    Accordingly, implementation of the present invention provides a plurality of angled abutments  22  (see  FIG. 1  and abutments  22   a - d ) with bores  28  at differing angles, for selective installation. In an alternate embodiment, the abutment  22  defines opposing base surface and seating surface with a threaded bore through the seating surface into the abutment. The base surface is defined at various angles to offset the angle of the installed implant member, so that the seating surface is substantially horizontal for receiving a fastener into the bore at a substantially vertical orientation. 
         [0035]    The rail  14  secures with the clip assembly  24  to the abutment  22 . The clip assembly  24  includes a lower clip  30 , an opposing upper clip  34  and an assembly locking member  36 . The rail  14  is held between the lower clip  30  and the upper clip  34 , as discussed below. In the illustrated embodiment shown in  FIG. 2 , each clip assembly  24  further includes a spacer column  32 . The spacer column  32  defines an axial passageway  37 . In the illustrated embodiment, the spacer column  32  defines a threaded distal end  38 . The securing member  36  is a nut threadably received on a threaded distal end  38  of the spacer column  32 . A clip assembly screw  40  extends through the nut  36 , the open end of the spacer column  32 , and through the passageway  37 , and engages the threaded bore  28  in the abutment  22 . The clip assembly screw  40  attaches the clip assembly  24  to the abutment  22 . The angled bore  28  in the abutment  22  provides for gross correction to vertical from the angulation of the implant  20  for receiving the clip assembly  24  that holds the rail  14 . The rail  14  is secured between the opposing lower clip  30  and the upper clip  34 . 
         [0036]      FIG. 3  is a detailed prospective view of an embodiment of the upper clip  34 . The upper clip  34  comprises a member  42  having an arcuate wall portion  44  and opposing planar sides  46 ,  48 . A lip  50  extends laterally. The lip  50  is configured for receiving an edge of the rail  14 . In the illustrated embodiment, the lip  50  projects laterally from the member  42  and defines a beveled face  52  facing an abutment wall  54 . The member  42  defines a through passage  55 . The lower clip  30  in one embodiment has the same structure as the upper clip  34 . In this embodiment of the clip assembly  34 , the spacer column  32  is a separate member received in the passageway of the lower clip  30 . 
         [0037]      FIG. 4  illustrates an alternate embodiment of the lower clip  30  and the spacer column  32  as a unitary member  58 . The spacer column  32  extends from the lower rail clip  30  and defines the through passageway  37 . The distal end  38  of the spacer column  32  is threaded. The spacer column  32  is manufactured in selected lengths, so as to position an upper end thereof proximate, or slightly above, the surface of the gum tissue of a patient. 
         [0038]      FIG. 5  is a prospective view of the rail  14  for the full arch assembly  10 . The rail  14  is an elongated metal band having opposing edges  64 ,  66 . The edges  64 ,  66  in the illustrated embodiment are beveled for mating contact with the respective beveled surface  52  of the opposing lower and upper clips  30 ,  34 . 
         [0039]    With reference to  FIG. 2 , the securing member  36  or nut threads on the upper end of the spacer column  32 . Tightening the nut  36  secures the rail  14  rigidly between the lower clip  30  and the upper clip  34 . In an alternate embodiment, a portion of the rail  14  seats on the lower clip  30  and the clip assembly screw  40  secures the upper clip  34 , the rail, and the lower clip to the abutment  22 . 
         [0040]      FIG. 6  is a prospective exploded view of a dental prosthesis using the rail  14  for the anterior dental arch and a posterior rail  70  along the pre-molar and molar region of the arch. The rail  70  extends between an anterior implant assembly  12   a  and a posterior implant assembly  12   b . The rail  14  extends arcuately anterior of the incisors and terminates with a cantilever portion  71  longitudinally beyond the anterior implant assembly  12   a . In this embodiment, one end of the rail  70  includes a ring  72 . The ring  72  seats on the upper rail clip  34  concentric with the passageway  37  of the clip assembly  34  for the anterior implant assembly  12   a . The rail  70  extends to the posterior implant assembly  12   b  and may also include a posterior cantilever portion  90  thereof. 
         [0041]      FIG. 7  illustrates a denture  80  molded of a conventional material to which a plurality of teeth  82  attach. The denture  80  defines a U-shape in cross-section for arching over a maxillary or mandibular ridge of a patient. A shown in partial cut-away view, the rail  14  seats within the arch of the denture  80 . 
         [0042]    With reference to  FIG. 1 , the dental prosthesis  10  is assembled and installed chair side for a patient. Briefly and in summary, the implant assemblies  12  are selectively positioned in selected locations of the maxillary bone structure of the patient. The denture (pre-configured) is placed in the patient&#39;s mouth on the abutments  22  on the respective distil end of the implants  20 . Each of the screws  26  extends through a respective abutment  22  and threadedly engages the dental implant  20  to fixedly secure the abutment  22  to the dental implant. The lower clip  30  and spacer column  32  (separate members or unitary) are positioned on the abutment  22 . The hollowed out denture  80  is seated over the assemblies  24  and the rail  14 . The upper clip  34  is positioned on the threaded end of the clip member  32  so that the beveled surfaces  52  of the lower and upper clips  30 ,  34  are in opposing facing relation. The nut  36  is loosely threaded on the threaded end  38  of the spacer column  32 . The rail  14  seats so that the beveled edges  64 ,  66  contact the beveled surfaces  52  of the opposing lower clip  30  and upper clip  34 . The screws  40  are tightened to secure the clip assemblies to the abutments and hold the rail  14 . 
         [0043]    In greater detail, the assembly and installation of the dental prosthesis  10  is described below. First, prior to chair side assembly of the dental prosthesis  10  in accordance with the present invention, a conventional denture is made. This involves taking an impression or casting of the patient&#39;s maxillary or mandibular ridge that will receive the dental prosthesis  10  as a bridge or replacement denture. As shown in  FIG. 1 , this may involve a full denture, while an alternate embodiment may use implant assemblies  12  with the rail  14  mounted there between as a bridge along a portion of the dental arch where several teeth may be missing, for example, the incisors portion of mandibular jaw. The denture is fabricated conventionally with porcelain or acrylic teeth embedded in denture material. Further, x-ray, photographic, or digital images are made of the patient&#39;s alveolar structure. The oral surgeon analyzes the images of the alveolar bone structure and determines a suitable location and angular orientation of the implant assemblies  12 . For example, the upper jaw has a sinus cavity that should be avoided while the lower jaw has nerves that likewise need to be avoided. 
         [0044]    The implant assemblies  12  are placed conventionally. This involves drilling pilot holes in the selected location and angle. The process of drilling the pilot holes provides the surgeon with information as to bone density. Angled installation of implants provides longer engagement of the implant with the bone and provides better mechanical stability. Pilot holes may be drilled with successively larger diameters. The implant  20  screws into the drilled hole in the bone structure. The length of the implant  20  is selected so that an upper end of the implant  29  is disposed proximate, at or just below, the soft tissue gingival line of the patient. The abutments  22  are then attached. The abutments  22  correct gross angulation error of the implants  20  in order to provide the substantially vertical orientation of the threaded bore  28  of the abutment. The abutment  22  is selected so as to have an end disposed projecting above the surface of the soft tissue. 
         [0045]    The denture is prepared for fitting. An impression material is placed within the open bottom of the denture. The denture is seated on the jaw. The patient then bites down firmly. Each of the abutments  22  makes an indention in the impression material. The denture is removed. The point of contacts of the abutments  22  are drilled through the denture. This creates an opening for access to the abutment. An opening in the denture is made for each implant. 
         [0046]    The rail  14  is then adapted to the denture  80 . It may be necessary to grind the denture from below to define a channel for the rail  14  within the interior arch of the denture as shown in  FIG. 8 . With continuing reference to  FIGS. 1 and 2 , the lower clip  30  with the spacer column  32  is positioned on the abutment  22 . The denture is positioned on the alveolar ridge of the patient. This seats the lower edge  64  of the rail  14  on the lower rail clip  30 . The beveled edge  64  matingly contacts the beveled face  52  and a side of the rail abuts the wall  54 . (It is to be appreciated that in a first embodiment, the lower rail clip  30  and the spacer column  32  are separate members, or as illustrated in  FIG. 4  may be an integrated member.) 
         [0047]    With access through the opening in the denture, the upper clip  34  seats on the distal end of the spacer column  32 . The upper edge  66  similarly matingly engages the beveled face  52  of the upper rail clip  34  and the side of the rail  14  abuts the wall  54 . The nut  36  threads on the threaded end  38  of the spacer column  32 . The rail  14  is thereby held between the lower clip  30  and the upper clip  34 . The assembled clips  30 ,  34  are loosely held clamping the rail  14  between them. The clip assembly screw  40  extends through the opening formed in the denture and through the nut  36  received on the threaded end of the spacer column  32 . The screw  40  extends through the passageway  37  and threadably engages the threaded bore  28  in the abutment  22 , to thereby secure the clip assembly  24  to the abutment  22 . This step is repeated for each of the at least one other dental implant  20  as would be the case for a bridge having two implants or additional three or more implants for a full arch reconstruction. 
         [0048]    A liquid acrylic is poured around the opening in the denture including around the lower clip  30 , the upper clip  34  and assembly locking member  36 . The liquid acrylic is cured. This holds the rail  14  with the clips  30 ,  34 . The fastener  40  is unthreaded. The assembly of the denture with the rail  14  and the clip assemblies  24  may then be removed as unitary piece. The edges of the denture may then be smoothed to abut the soft tissue of the gingiva over the alveolar ridge. The denture or bridge assembly is replaced in the patient&#39;s mouth, and the assembly is secured in place with the clip assembly screws  40 . The structure of the rail  14  secured by the clip assemblies  24  to the abutments  22  provides a passive fit for the denture. The rail  14  secured by the clip assemblies does not apply force to the implants  20 . The openings in the denture are closed with a curable denture material. 
         [0049]    The apparatus and method disclosed herein can be made and executed without undue experimentation in light of the present disclosure. While the apparatus and methods of this invention have been described in terms of illustrative embodiments, it will be apparent to those of skill in the art that variations may be applied to the apparatus and in the method steps or in the sequence of steps thereof described herein without departing from the concept, spirit and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims.