Abstract:
A dental articulator for use in dental education simulates the human mouth and has an adjustable hinge that interconnects upper and lower carrier trays for movement to and from a closed position. Modules of imitation gums and teeth are secured in the carrier trays by neodymium magnets. The hinge structure in the articulator is selectively movable to shift the jaw axis to a position to provide the desired alignment of the upper and lower teeth when the jaw is closed or demonstrate a misaligned condition. A dental training module may be installed which, upon removal from the articulator, has a pair of separable sections encasing a tooth to permit release of the tooth and removal from the module so that a completed treatment may be evaluated.

Description:
[0001]    This application is a continuation-in-part of application Ser. No. 11/784,806, filed Apr. 10, 2007. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to improvements in dental articulators and simulated components of the human mouth utilized as a teaching tool and a demonstrative aid, and to the training of dentists or dental students in dental procedures. 
       BACKGROUND OF THE INVENTION 
       [0003]    As a training aid in dentistry, a replica of the mouth or manikin is utilized so that the student can learn and practice dental procedures and develop a high level of skill before performing a procedure on a patient. The complexity of such procedures and the high level of precision required is set forth, for example, in U.S. Pat. No. 6,988,894, owned by the assignee herein. The manikin or dental articulator is a replica of the human mouth containing gum and tooth modules that may be inserted and removed as needed for a particular procedure. Also, an articulator may be used to show a patient a particular dental condition or facilitate explanation of a particular procedure and the manner in which it is performed. 
         [0004]    Dental articulators, however, are typically provided with a fixed jaw axis which does not facilitate adjustment of the relative positions of the upper and lower jaws to correct misalignment that may occur in the day-to-day use of the articulator. Furthermore, there are instances in which it is desired to demonstrate an intentional misalignment by shifting the jaw axis, or correcting a misaligned manikin by adjusting the axis to a proper location. Gum and tooth modules may not be readily removed from the articulator, and procedures performed on embedded natural or artificial teeth may not be easily evaluated. 
       SUMMARY OF THE INVENTION 
       [0005]    In an embodiment of the present invention an improved dental articulator is provided for use in dental education. The articulator simulates the human mouth and provides an adjustable hinge which permits proper alignment and, therefore, proper occlusion to be maintained, or an intentional misalignment demonstrated, for use in training in dental school and by dentists to demonstrate to patients. 
         [0006]    One aspect of the present invention is the utilization of hinge structure that provides a jaw axis in a dental articulator that is selectively movable transversely to a fixed position where the axis provides the desired alignment of the upper and lower teeth when the jaw is closed. Alignment is further assured in an embodiment of the present invention by the utilization of an adjustable ball and recess connection to the upper jaw which provides both a proper lateral and vertical orientation with respect to the lower jaw. 
         [0007]    Another aspect of the invention is the utilization of a hinge structure in a dental articulator having components that are selectively movable to a fixed position where the jaw axis provides the desired alignment in the closed position of the upper and lower teeth. 
         [0008]    A further aspect of the invention is to provide hinge pins in a dental articulator that establish the desired jaw axis and are selectively movable to positions that provide proper alignment of the upper and lower jaws, and which may be secured in such positions to maintain the aligned condition. Furthermore, each hinge pin is held by a spring and, when desired, may be moved against the bias of the spring to shift the jaw axis to a misaligned condition for demonstration purposes and then released for return to the aligned condition. 
         [0009]    Additionally, the present invention in another aspect thereof provides an endodontic training module adapted to be removably installed in a manikin and which includes an insert having a endodontic tooth therein upon which a student may perform a procedure while the module is in the manikin. The insert has a pair of separable sections encasing the tooth while the insert is in the module, and permitting release of the tooth upon removal of the insert from the module after an endodontic procedure so that the completed treatment may be evaluated. 
         [0010]    An additional aspect of the invention is the provision of a carrier tray for a dental articulator having a base plate recessed at desired module locations and provided with a series of flat, side-by-side permanent magnets in each of the recesses presenting surfaces at each of the module locations substantially flush with the mounting surface, each of the modules having a plate of magnetic material therein overlying the magnets at the corresponding location to thereby releasably hold the modules in the tray. 
         [0011]    Other advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, an embodiment of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a side perspective view of the dental articulator with the mouth closed. 
           [0013]      FIG. 2  is a fragmentary view of the articulator showing two of the members that are connected to the upper and lower carriers, as seen looking along the axis of the hinge. 
           [0014]      FIG. 3  is a detail view of one of the axle hinge components partially broken away and shown in cross section, a compression spring being illustrated in broken lines. 
           [0015]      FIG. 4  is an exploded view of the hinge parts. 
           [0016]      FIG. 5  is a detail view of the compression spring and shoulder ring. 
           [0017]      FIG. 6  is a plan view of the lower carrier tray. 
           [0018]      FIG. 7  is a detail view showing one of the magnet assemblies utilized in the tray of  FIG. 6 . 
           [0019]      FIG. 7   a  is a longitudinal cross-sectional view of the magnet assembly of  FIG. 7 . 
           [0020]      FIG. 8  is a perspective view looking at the interior face of modules that are magnetically held within the lower carrier tray. 
           [0021]      FIG. 9  is a perspective view of the endodontic module removed from the carrier tray, a breakaway insert containing a simulated tooth being shown partially withdrawn from the module. 
           [0022]      FIG. 10  is a bottom view of the endodontic module. 
           [0023]      FIG. 11  is an exploded, elevational view showing the insert fully withdrawn from the module, the phantom lines illustrating the teeth of the insert when the latter is fully installed in the endodontic module before removal therefrom. 
           [0024]      FIG. 12  is a bottom view of the insert. 
           [0025]      FIG. 13  is an exploded, elevational view showing the two sections of the insert after they are separated, both sections shown from the interior side. 
           [0026]      FIG. 14  is an exploded view in elevation showing the simulated tooth removed from the insert. 
           [0027]      FIG. 15  is a fragmentary, plan view showing a modified form of upper carrier tray which provides a ball and recess connection to the upper support members. 
           [0028]      FIG. 16  is a view similar to  FIG. 15  illustrating a maximum lateral displacement of the adjustable tray, parts being broken away to reveal the ball and recess connection. 
           [0029]      FIG. 17  is a side elevational view of the carrier tray of  FIGS. 15 and 16  illustrating the ability of the connection to provide up and down adjustability. 
           [0030]      FIG. 18  is an exploded, detail view showing the components of the ball and recess connection. 
       
    
    
     DETAILED DESCRIPTION 
     FIGS.  1 - 14   
       [0031]    Referring initially to  FIGS. 1 and 2 , a dental articulator  20  presents a manikin having an upper carrier tray  22  and a lower carrier tray  24  which receive and hold individual modules of imitation gums and teeth, upper such module  26  and two lower modules  28  and  30  being seen in  FIG. 1 . Also, as will be discussed more fully hereinafter, the upper tray  22  receives and holds an endodontic module  32  having a breakaway insert  34 . The trays  22  and  24  are rotatable about a transverse axis provided by adjustable, left and right hinge components  36  and  38  which establish an axis about which articulated members connected to the trays  22  and  24  rotate; specifically, axially spaced outer, lower members  40  and  42  connected to the rear edge of lower carrier tray  24  in the conventional manner, and spaced inner, upper members  44  and  46  connected to the rear edge of the upper carrier tray  22 . To open and close the articulator (shown in the closed condition), one or both of the carrier trays  22  and  24  are rotated about the axis provided by the hinge components  36  and  38 . A mounting ring  48  is integral with inner members  44  and  46  and centered therebetween to provide a means of supporting the manikin on a post (not shown) and tightening ring  48  thereon by a manually adjustable screw  50 , as is conventional. 
         [0032]    The hinge structure is shown more fully in  FIGS. 3-5  where the hinge component  38  and associated parts are revealed in detail, it being understood that hinge component  36  on the opposite side of ring  48  is constructed in the same manner to provide a continuous axis  52  from outer member  40  to outer member  42 . A hinge component or pin  54  has an enlarged end presenting a knob  55  coaxial with the shaft  56  of the pin  54 , the pin  54  terminating at its opposite end in a threaded portion  58  of smaller diameter. As will be discussed, the hinge pin assembly is completed by a shoulder ring  60 , washer  62  and nut  64 . 
         [0033]    Outer member  40  has a tubular upper end portion  40   a  through which shaft  56  extends at a right angle.  FIG. 3  shows the hinge pin  54  in place with shaft  56  extending through an elongated opening  68  near the upper end of outer member  40 , across end portion  40   a  and inward into an axial opening  70  in the outer end of inner member  44  aligned with axis  52 . The hinge is assembled by inserting shaft  56  with shoulder ring  60  thereon through opening  68  and on into axial opening  70  with washer  62  disposed between members  40  and  44 . An opening  72  in the member  44  communicates with axial opening  70  to permit insertion of nut  64  in the assembly of the hinge. It should be noted that the axial opening  70  in the outer end portion of inner member  44  is oversized with respect to the diameter of the shaft  56  of the hinge pin  54  to permit adjustment of the axis  52  as will be discussed. 
         [0034]    Referring to  FIGS. 3 and 5 , a compression spring in the hollow outer end of member  40  operates between a removable end plug  76  and a cut  78  that mates with shoulder ring  60  on the shaft  56  of hinge pin  54 . The spring  74 , therefore, maintains shaft  56  at the bottom end of elongated opening  68  as seen in  FIGS. 2 and 3 . 
         [0035]    The adjustable hinge component  36  associated with tubular end portion  42   a  of member  42  is constructed in the same manner as described above for hinge component  38  and completes the axis  52  about which the upper carrier tray  22  may be rotated to simulate the opening and closing of the jaw. As will be discussed more fully hereinbelow, adjustment of the axis  52  is provided by the oversize opening  70  and cooperating parts in each of the two hinge assemblies. 
         [0036]    Referring to  FIGS. 6-8 , the lower carrier tray  24  is shown in detail. In  FIG. 6  the modules  28  and  30  are removed and, additionally, a module  29  ( FIG. 8 ) not visible in  FIG. 1 . The tray  24  is composed of a nonmagnetic material such as aluminum and has three magnetic assemblies  80  therein, each of which is secured in a corresponding rectangular recess  82  and creates a closed magnetic field. Each of the magnet assemblies  80  comprises three neodymium magnets side-by-side presenting upwardly facing, alternating poles as shown in  FIG. 7  (south, north and south). Each of the three magnet assemblies  80  is held in a non-magnetic, e.g. plastic, frame  84  as seen in  FIGS. 7 and 7   a . Preferably, the total thickness of the magnet and frame assembly is approximately three millimeters with the magnets themselves having a thickness of less than two millimeters, and thus the assembly is accommodated without increasing the thickness of the tray. The rectangular recesses  80  in tray  24  are complimental to the frame  84  and provide a flush fit with the upper surfaces of the magnets  80  co-planar with the interior surface  85  of the tray  24 . Upper tray  22  is of identical construction. 
         [0037]      FIG. 8  shows the two gum modules  28  and  30  (teeth are not shown) seen in  FIG. 1  and a module  29  hidden from view in  FIG. 1  which, as a group, are insertable into lower tray  24 , a tab  86  at the anterior tip thereof being received in a corresponding slot  88  in the tray  24 . Each of the modules  28 ,  29  and  30  has a rectangular plate  90  of magnetic material (such as steel) embedded therein with its outer surface flush with the bottom surface of each of the modules. These plates  90  register with corresponding magnet assemblies  80  upon insertion of the modules into the tray, thereby securing the modules within the tray until forceably released therefrom by a quick manual pull on the module. Though illustrated herein in the lower tray  24 , it is to be understood that the magnetic assemblies  80  may also be used to secure modules in the upper tray  22  of the articulator  20 . 
         [0038]    Use of the articulator of the present invention in connection with an endodontic procedure is illustrated in  FIGS. 9-14 . The module  32  comprises a simulated plastic gum  92 , a pre-formed socket  94  in the module, a dummy tooth  96 , and the breakaway insert  34  (partially withdrawn) having a dummy tooth  100  and a simulated tooth  102  (either upper or lower) upon which an endodontic procedure may be practiced. 
         [0039]      FIG. 10  shows the bottom of the module  32  where a plate of magnetic material  104  is recessed into the base of the module for releasably securing the module in the upper carrier tray  22  of the articulator ( FIG. 1 ). After a dental procedure is performed on the tooth  102  (which may be a lower tooth as well as an upper tooth procedure), the module  32  is released from the manikin so that the tooth  102  may be inspected and the quality of the student&#39;s work determined. The insert  34  is withdrawn as illustrated in  FIG. 11 , facilitated by a release hole  105  in the base of the module  32 . A slot  106  in the base of the insert  34  ( FIG. 12 ) permits the breakaway action by insertion of a small coin or similar object (not shown) into the slot  106  and, by a twisting action, separating the insert into its two mating sections  34   a  and  34   b .  FIGS. 13 and 14  reveal a small tab  108  on section  34   b  which is tightly received within an opening  110  in section  34   a  to hold the mating sections together in properly aligned relationship until separation. 
         [0040]    As may be appreciated from  FIGS. 13 and 14 , the simulated tooth  102  is received within aligned recesses  112  in section  34   a  and  114  in section  34   b  when the insert  34  is in its closed condition as seen in  FIGS. 11 and 12 . Accordingly, when the sections  34   a  and  34   b  are released, the endodontic tooth  102  previously held in the recesses  112 ,  114  may be removed as illustrated in  FIG. 14  and the work of the student evaluated by the instructor. For example, for a root canal procedure, the instructor can visualize complete treatment of the canals as well as check for perforations that may have been made through the canal or pulp floor during the procedure. This is accomplished by simple visual inspection without the necessity of radiographic analysis, for example, that would be required in order to evaluate an encased tooth. Furthermore, the endodontic module  32  may be reused repeatedly by replacing the insert  34 . 
       FIGS.  15 - 18   
       [0041]    A modified form of carrier tray  122  is shown in  FIGS. 15-18  and provides additional adjustability to assure proper alignment in the closed condition of the articulator  20 . Spaced upper arm members  144  and  146  are interconnected at their distal ends by a crossbar  200  shown in  FIG. 15  engaging the rear edge  202  of tray  122 . This is the normal position of the crossbar  200  when the adjustable, left and right hinge components  36  and  38  described hereinabove provide adequate adjustability to properly align the upper and lower carrier trays  22  and  24  as shown in  FIG. 1 . However, if additional adjustment is required to provide the proper alignment, the upper carrier tray  122  may be shifted to the left or right as illustrated in  FIG. 16  or pivoted upwardly or downwardly as illustrated in  FIG. 17 , by a ball and recess connection shown in detail in the exploded view of  FIG. 18 . 
         [0042]    More particularly, the crossbar  200  has a shank or stem  206  at its longitudinal center projecting forwardly and presenting a ball  208  which is received within a corresponding recess  210  in the rear edge  202  of tray  122  to provide a ball-and-socket connection ( FIGS. 15 ,  16  and  17 ). The ball  208  is held in socket  210  by a cover plate  212  received in an opening  213  and secured by a pair of screws  214 . The plate  212  is removed in  FIG. 16  to reveal the shank  206  and ball  208 , and is shown in place in opening  213  in  FIG. 15  secured by screws  214  to thereby clamp the ball  208  and lock it in the selected position. In  FIG. 15  the ball  208  is essentially fully inserted in the slot  210  and the bar  200  is in engagement with surface  202 , whereas in  FIG. 16  an extreme adjustment is illustrated and shows rotation of the tray  122  to the right. Accordingly, left to right adjustability is provided by the ball and recess connection upon loosening the screws  214 , shifting the tray  122  to the desired position that will provide proper alignment of the teeth, and then tightening the screws  214 . 
         [0043]    Furthermore, up and down adjustability about the ball  208  is also provided by the ball-and-socket connection upon loosening the screws  214  and swinging the tray  122  to the desired position. Comparison of the full and broken lines in  FIG. 17  illustrates the capability of providing a range of adjustability that assures accurate positioning of the simulated upper teeth relative to the lower teeth at the proper alignment or demonstration of an intentional misalignment. Also, it should be appreciated that the lower carrier tray  24  ( FIGS. 1 and 6 ) may be modified in the same manner as described above for upper carrier tray  122 , thereby providing either or both trays with full adjustability. 
         [0044]    It is to be understood that while certain forms of embodiments of this invention have been illustrated and described, it is not limited thereto, except insofar as such limitations are included in the following claims and allowable equivalents thereof.