Abstract:
A premanufactured dental model base, and method, for supporting a cast dental model. The dental model base has a dental model support surface adapted such that a user may create apertures in the dental model support surface. The apertures are adapted to receive pins that secure the dental model to the dental model base and for disengagably retaining a dental model segment representing a damaged tooth.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation-in-part of U.S. Ser. No. 09/349,192 filed on Jul. 7, 1999 now abandoned which is herein incorporated by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   This invention relates to dental model bases and methods of forming dental models. 
   2. Related Art 
   A successful repair of damaged teeth either by bridge inlays, replacement by crowns, or other common dental prostheses requires accurate alignment and visual uniformity of the repaired tooth with the patient&#39;s other teeth. Typically a model is made of the patient&#39;s teeth and the prosthesis is fitted to the model and adjusted to achieve proper alignment and visual uniformity. 
   The model is typically formed by having the patient bite into a pliant casting material that cures to create a mold cavity having a negative impression of the patient&#39;s teeth and gums. The mold can be of all or any portion of the patient&#39;s gum line. A castable material is then poured into the negative impression to create a stone replica of dental model of the patient&#39;s teeth and gums. 
   To facilitate prosthesis development, the replica of the damaged tooth or teeth is severed from the remainder of the dental model. Severability is achieved by positioning the tapered end of the dowel pin in an aperture formed in the dental model base that corresponds to the damaged tooth or teeth. Typically, the aperture is formed as part of the dental model base during manufacture or is formed in a cast stone base by allowing the stone to cure around a pin. The knurled end of a tapered dowel pin is placed in the stone material in the negative impression in correspondence with the damaged tooth or teeth. To prevent bonding of the damaged tooth model with the dental model base, wax may be placed between the dental model base and the dental model. 
   Once the dental model has cured, a saw cut on each side of the damaged tooth model is made down to the dental model base that allows removal of the damaged tooth model and attached dowel from the rest of the dental model. After the damaged tooth model is removed, the prosthesis can be fitted and adjusted without the spatial limitations encountered when the damaged tooth model is joined to the full dental model. After the prosthesis is made and attached to the dental model segment, the tapered dowel, dowel pin or pins attached to the dental model segment is guided into the respective premanufactured aperture or apertures, in the dental model base which determines the dental model segment in the dental model. Alignment and visual conformity are then assessed. 
   Alignment is ascertained by evaluating the registration of the repaired tooth with the dental model of the patient&#39;s opposing teeth. This is achieved by connecting the upper and lower dental model with an articulator. In some situations, a disposable articulator such as the Vertex® articulator is preferred. In other situations, a traditional metal articulator is preferred. If the prosthesis is out of alignment or does not visually conform to the rest of the patient&#39;s teeth, the dental model segment containing the damaged tooth can be removed, adjusted and returned to the dental model base. This process is repeated until proper alignment and visual conformity are achieved. Thus, the model of the damaged tooth may be repeatedly engaged and disengaged with the dental model base. 
   SUMMARY OF THE INVENTION 
   A dental model base is provided. The dental model base includes a dental model base body having a dental model support surface. The dental model support surface is adapted for formation of an aperture corresponding to a model of a specific damaged tooth. The dental model base body is also configured to be disengagably connected to an articulator attachment plate. 
   In accordance with another aspect of the invention a dental model base is provided having a dental model support surface. The dental model support surface is adapted for the formation of an aperture corresponding to a model of a specific damaged tooth. The dental model base is also configured to be disengagably connected to a disposable articulator. 
   In accordance with another aspect of the invention a dental model base is provided having a dental model support surface configured for formation of apertures. The dental model base includes a dental model base body having a first end and a second end. The end has a receiver socket adapted to engage a ball. The first end also has a slot adapted to engage a disposable articulator. 
   In accordance with another aspect of the invention, a kit is provided comprising a dental model base body having a support surface configured for the formation of apertures. The dental model base is configured to be disengagably connected to an articulator attachment plate. The kit further includes an articulator attachment plate. 
   In accordance with another aspect of the invention, a method of detachably connecting a model of a damaged tooth to an articulator is provided. The method includes casting a negative impression of at least a portion of a patient&#39;s teeth. The method includes identifying on the support surface the desired location of a pin to support a model of a damaged tooth. An aperture is created in the support surface corresponding to the desired pin location. A pin is placed in the aperture so that a first end extends from the support surface. The method further comprises placing the dental model support surface into the casting material and curing the casting material. The dental model and dental model base are removed from the impression. The method further includes cutting adjacent the model of the damaged tooth so that the damaged tooth may be separated from the dental model. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, wherein like numerals represent like parts throughout several views, in which: 
       FIG. 1  is a perspective view of an embodiment of a dental model base of the present invention; 
       FIG. 2  is a perspective view of an alternative embodiment of a dental model base of the present invention; 
       FIG. 3  is a perspective view of a further alternative embodiment of a dental model base of the present invention; 
       FIG. 4  is a bottom perspective view of an embodiment of a dental model base of the present invention; 
       FIG. 5  is a perspective view of a further alternative embodiment of the present invention; 
       FIG. 6  is a side view of a dental model base and attachment plate according to the present invention; 
       FIG. 7  is a side view of a dental model base and attachment plate according to the present invention; 
       FIG. 8  is a side view of a dental model base and attachment plate according to the present invention; 
       FIG. 9  shows a disposable articulator connected to two dental model bases of the present invention; 
       FIG. 10  is a perspective view showing an attachment plate and a dental model base according to the present invention; 
       FIG. 11  is a perspective view of an impression and a holder. 
   

   While the invention is amenable to various modifications and alternative forms, the specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to particular embodiments described. On the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The present invention is believed to be applicable to dental models and dental model bases for mounting dental models. In particular, the present invention is directed to a dental model base having a base body that is configured to mount a dental model and is further configured to be disengagably connected to an articulator attachment plate. While the present invention may not be so limited, an appreciation of various aspects of the invention will be gained through a discussion of the examples provided below. 
     FIG. 1  depicts a dental model base  10  according to one embodiment of the present invention. The dental model base may be constructed of any material or set of materials sufficiently strong and rigid to support a dental model. The dental model base may be constructed of, for example, a polycarbonate material such as Lexan® brand polycarbonate material by General Electric Company. The dental model base may also be made of other materials such as polymers, ceramics, metals, metal alloys, stone, fiberglass, composites, or the like. As shown in  FIG. 1 , the dental model base  10  has a dental model support surface  12 . The shape of the dental model support surface  12  follows the general contours of normal gums. The dental model base  10  is configured to support a full arch dental model. 
   On the outside of the dental model base  10  there is a positive protrusion  2  that is the location marker for the cuspid and a positive protrusion  4  that is the location marker for the first molar (See FIG.  1 ). While protrusions shown here correspond to the cuspid and first molar locations, it should be understood that the aligning of the impression with the dental model base may be achieved with a marking on any other location of the dental model base. The protrusions are aligned with the marks on the impression during the pouring stage. The dental model base  10  is held in it&#39;s final position over the impression and the teeth locations are marked on the inside of the plastic base in preparation for drilling the hole  50  to receive the metal dowel pin  104  (See FIGS.  1  and  10 ). It is noted that the alignment for the dental model base with the impression can utilize any form of marking. The marking does not have to be a protrusion on the dental model base. The marking may be an indentation or a painted or colored marking or any other form of identifying a location that can be aligned with a marking on the impression. Likewise, the marking on the impression can take any form that allows a location to be identified. 
   In the embodiment dental model base shown in  FIG. 1 , a plurality of tapered pins  14 ,  16  are formed with the dental model base support surface  12 . In this embodiment of the invention, there is a line of indexing pins  16  arranged along the inner periphery of the dental model support surface  12  and a line of indexing pins  14  along the outer periphery of the dental model support surface  12 . The pins  14 ,  16  may be formed of the same material as the dental model base  10  and model support surface  12 . The pins  14 ,  16  may releasably engage a cast dental model. 
   The external wall  18  extends from the dental model support surface  12  on the opposite side of the support surface from the external line of pins  14  (See FIG.  1 ). The external wall  18  generally follows the periphery of the dental model support surface  12 . An internal wall  20  extends from the dental model support surface  12  on the opposite side of the dental model support surface from the internal line of pins  16 . The internal wall  20  generally follows the periphery of the dental model support surface  12 . A rear portion  22  of the dental model base  10  includes an articulator attachment groove  24  and two hemispheric sockets  26 . 
   As shown in  FIG. 4 , the front  28  of the dental model base  10  has a recess  30  forming a notch  32  to which an articulator attachment plate  38  may be disengagably attached, as shown in FIG.  6 . 
     FIG. 5  depicts a base  34  configured to support a quadrant arch dental model. As shown, the quadrant arch base  34  has a socket  72  at the rear  70  of the quadrant arch base  34 . The rear  70  of the quadrant arch base  34  has an articulator attachment groove  36  formed across a hemispheric socket  72 . In other embodiments, the attachment groove  36  is formed at the rear  70  of base  34 , but is not formed across socket  72 . In this embodiment, there is an internal line of pins  74  and an external line of pins  76  on the model support surface  78 . The external line of pins  76  generally following the periphery of the dental model support surface  78 . 
     FIG. 6  is a perspective view of an embodiment of the present invention. An articulator attachment plate  38  has an articulator attachment side  40  and a base engagement side  42 . A hook  44  is at one end of the attachment plate  38 . A hemisphere or ball  46  is connected to the opposite end of the attachment plate  38  by a hemisphere connecting member  48 . The attachment plate  38  is connected to the base  10  by placing the hemisphere or ball  46  in the socket  26  formed in the rear  22  of the base  10 , as shown in FIG.  6 . The attachment plate is then rotated about the ball  46  and socket  26  relative to the base  10 . 
   As shown in  FIG. 7  the hook  44  slidingly engages the recess  30  in the base  10 . As pressure is applied to join the base  10  and the attachment plate  38 , the hook  44  slides along an inclined plane of the recess  30 . When the attachment plate  38  is properly engaged with the base  10 , as shown in  FIG. 8 , the hook  44  engages the recess  30  and secures the attachment plate  38  to the base  10 . 
   The model is typically formed by having a patient bite into a pliant casting material that cures to create a mold cavity having a negative impression of the patient&#39;s teeth and gums. An example of a negative impression  54  of the patient&#39;s teeth and gums maintained in a holder  56  is shown in FIG.  11 . The mold can be of all or any portion of the patient&#39;s gum line. Any excess impression material or any material that would interfere with the proper positioning of the model base may be removed, while being careful not to remove any material that is needed to maintain the integrity of the impression. The cuspid and first molar locations are marked on the impression as a reference for positioning the dental model base. 
   A dental model support surface  12  may include any type of pin construction or alternatively no pins at all. For example, an alternative embodiment of the present invention is shown in  FIG. 2  showing an alternative configuration of pins  17  protruding from the dental model support surface  13 . Thus if desired, the dental model base support surface  13  of the dental model base  11  can have a single row of pins  17 . In this embodiment a hole  51  may be drilled or otherwise formed in the dental model support surface  13  is required by the technician to receive the dowel pin  104  (See FIGS.  2  and  10 ). 
     FIG. 3  is a further alternative embodiment showing a dental model base  31  with a dental model support surface  15  with no preformed pins. In this embodiment, a hole  53  can be drilled or otherwise formed in the dental model base support surface  15  by the technician to receive the metal dowel pin. 
   A dental model base  10  according to the present invention may be used with the mold cavity such that a technician can drill or form at least one aperture  50  in the dental model base support surface  12  corresponding to the location of a damaged tooth or teeth. The apertures may have a taper, such as for example, a two-degree taper (See FIG.  1 ). 
     FIG. 10  shows a dental model base  80  that is held in its final position over the impression and the teeth locations are marked on the inside of the dental model base  80  in preparation for drilling or otherwise forming a hole  82  to receive the metal dowel pin  104 . If desired, the hole  82  is drilled into the dental model base  80  at each marked location. A metal pin is not needed for every tooth and only the teeth that will be needed in the fabrication of the dental prosthesis are pinned. 
   A tapered metal dowel pin  104  is inserted into each drilled aperture  82  or apertures, in the dental model support surface  84  with enough pressure to insure that it will not become dislodged during the pouring process (See FIG.  10 ). The dowels typically have a two-degree taper on one end and knurling on the opposite end. The tapered end slidingly engages the apertures drilled in the dental model support surface and the knurled end is aligned with the negative impression of a tooth or teeth. 
   A castable material is then poured into the negative impression to create a stone replica or dental model of the patient&#39;s teeth and gums. First, the model stone is vacuum mixed with water to a thick, creamy mix. Next, the impression is held on a vibrator while the stone mix is teased into each tooth cavity. Further, the impression is filled to a level of ¼ to ⅜ of an inch above the margin or shoulder line of the teeth. A small amount of mix is teased around the knurled portion of the metal pins and also the plastic index pins that are sticking up from the surface of the base. The knurled end of a tapered dowel pin or pins protrudes from the dental model support surface and is positioned in the uncured stone material in correspondence with the damaged tooth or teeth by positioning the base and pin assembly adjacent the uncured dental model. Pins may be placed under other parts of the model at the discretion of the dental technician. 
   The dental model base  10  is then lowered into the impression while making sure to maintain proper alignment and position via the marks made prior to pouring. Any excess stone that is displaced may be very carefully removed. This will reduce the amount of stone that will need to be ground or trimmed after the stone has hardened. After the impression stone has hardened enough (usually about 20 to 30 minutes) then a mix of base stone  58  is poured into the plastic model base around the tapered portion of the pins and allowed to harden (See FIG.  10 ). Hardened stone model with plastic base attached is removed from the impression. Unneeded stone is trimmed away up to the model support surface  84 . Necessary teeth are sectioned and removed by carefully tapping the small end of the metal pin. Then each tooth preparation is trimmed to expose the margins at gum line in preparation for waxing. 
   Once the dental model is cured the mold may be removed. In one embodiment, shown in  FIG. 10 , the dental model segment of a damaged tooth  55  is disengagably connected to the dental model base. If desired, the dental model base may then be connected to a disposable articulator as depicted in FIG.  9 . As shown, a tongue of the disposable articulator engages the rear portion of the dental model base. Alternatively, a ball at each end of the disposable articulator could engage a socket at the ends of the dental model base. The same dental model base may also be connected to a traditional metal articulator. 
   The foregoing describes various embodiments of the claimed invention. The claimed invention is not limited to the embodiments described above. For example, it is contemplated that the principles of the invention described above can be applied to full arch dental model bases and quadrant model bases. It is also contemplated that this invention can be adapted for use with a variety of upper and lower gum sizes. Thus, numerous alternative constructions exist that would fall within the scope of the claimed invention.