Abstract:
A method, system and dental prosthesis are provided to facilitate simulation of the natural appearance of teeth. The prosthesis can be formed to include a component to which an aesthetic coating, such as a coloring or tint, can be applied. Further, the prosthesis can include a porcelain coating disposed on the outer surface thereof, and on top of the aesthetic coating, such that the aesthetic coating can be visible through the porcelain coating of the prosthesis. During production, the crown can be coated with a metal and/or ceramic powder by means of a powder printer that can be controlled by computer equipment. A practical and rapid application function can be obtained to produce an extremely natural-looking result.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a U.S. National Phase of International Application No. PCT/SE2005/001406, filed Sep. 23, 2005, which claims priority to Swedish Patent Application No. 0402360-2, filed Sep. 30, 2004, each of which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Inventions 
         [0003]    The present inventions relate to a method, apparatus, and system for obtaining on a dental prosthesis, and more specifically, a dental prosthesis that has, for example, a porcelain-coated crown with a coloring or tint that is visible from the outside of the prosthesis. 
         [0004]    2. Description of the Related Art 
         [0005]    It is known in the art that dental products such as porcelain-coated crowns can be manually colored or painted. It is also known, from other fields outside dentistry, that some components can be spray-coated with metal powder, such as in the Arcam® system, for example. Further, fully automated manufacturing systems for dental components have also been developed. For example, the Applicant of the present application uses the PROCERA® system. Other such systems and components are disclosed in Swedish patent application 0302971-1. 
         [0006]    European Patent Application Publication EP1396237A1, entitled Strengthened Ceramic Restoration, also discloses a system for producing fully ceramic tooth restorations where coloring can be achieved by immersing the tooth restoration in a suitable color. 
       SUMMARY 
       [0007]    An aspect of at least one of the embodiments disclosed herein is the realization that in the coloring and tinting dental products or parts thereof, there is a marked need to improve the techniques used and to speed up the manufacturing procedure. It is also preferable to allow the continued use of the techniques and equipment that are presently employed in the dental field without making too many modifications. In addition, there is a need in the art to substantially reduce production time associated with such manufacturing procedures. Thus, an aspect of at least one of the embodiments disclosed herein is the realization that in order to reduce the production time, time-consuming painting and immersing operations should be avoided. One of the objects of the present inventions is to remedy this problem, among others. 
         [0008]    In coloring and tinting, it is important to be able to optimize the coloring and tinting of a dental prosthesis to the environment within the oral cavity in which the prosthesis is to be used. The teeth of each patient have tints which are dependent both on the individual and on age, and there are considerable variations. It may be expedient to use general knowledge and experience to obtain a correct and natural-looking color. It is important in particular to accurately simulate and maintain the region of the front teeth. This region in particular requires the creation, for example, of a fully colored tooth which will merge with the other teeth in a natural-looking and optimal manner. Unfortunately, earlier work involving application by painting must be transferable to computer equipment environment which is used for natural-looking coloring, decoration, etc. The object of the invention is to remedy this problem too. 
         [0009]    In accordance with an embodiment of the present inventions, it is contemplated that during production, the crown can be coated with metal and/or ceramic powder by means of a powder printer (such as a pistol, nozzle, etc.) that can be controlled by computer equipment. 
         [0010]    In one aspect of a method of producing the crown can begin with an inner shape of the crown being milled out. The crown can then be applied on a die. On its top face, the crown can be coated with said metal and/or powder. The coating is dried thereafter, and molten wax is applied and profiled. The profiled wax is placed, together with the crown, in a cuvette and the wax is removed with heat. A space is thus created in the powder-coated surface, to which space the porcelain material is introduced and allowed to set. 
         [0011]    In an alternative embodiment, the porcelain-coated crown is built up with a number of layers applied on one another by means of spraying of metal(s) and/or ceramic(s) in powder form of each layer. Between or at the spraying operations, a function is initiated or included for coloring or tinting. The overall coloring or tinting can be effected by combination of coloring or tinting constellations applied on top of one another or after one another. 
         [0012]    In yet another embodiment, a dental prosthesis is provided, preferably in the form of a porcelain-coated crown. The prosthesis can comprise an inner coloring or tinting consisting of applied and dried metal and/or ceramic powder. In a preferred embodiment, the inner coloring or tinting can consist of layers of powder placed on top of one another. The coloring or tint can be chosen as a function of the coloring adjoining the prosthesis and/or teeth or can be chosen for decorative purposes. 
         [0013]    According to another embodiment, a system is provided in which a color printer (such as a pistol, nozzle, etc.) can be configured, as a function of activation, to emit powder jets directed toward the prosthesis or prosthesis part in question. The activations can be controlled or initiated by means of information from computer equipment which interacts with a user and, by actuations of the computer equipment, controls the coloring or tinting. 
         [0014]    In other embodiments of the system, information from the computer equipment can be transmitted to a production unit which can consist of an essentially fully automated manufacturing system, for example, in the form of Procera®, where the coloring or tinting functions can be input as a module unit in the other processing functions of the manufacturing system. An example of such a manufacturing system is described in abovementioned Swedish Patent Application 0302971-7. The color printer or the like can work essentially at approximately a 45 degree angle with respect to the actual surface to be coated in or on the dental prosthesis or the prosthesis part. 
         [0015]    By means of what has been proposed above, it is possible to obtain much more rapid and, generally speaking, more generalized coloring and tinting. The colors or tints can be built up from the inside, and the porcelain is transparent and, as a function of its configuration, can, together with the configuration of the crown, produce different refractions and appearances which in an excellent way simulate the natural appearance. The new advantages are especially marked in the region of the front teeth. 
         [0016]    The time factor is less critical, when using the invention, compared to previously used painting operations. Charts and library information can be organized based on the experience which is gradually gained in the field, and the fully automated manufacturing systems can be provided with CAD modules which can be adapted to already existing modules. The colors can be sprayed on and dried before, for example, pressing of the porcelain. The coloring can be diffuse and natural-looking and can be produced inside the prosthesis. The result can also be advantageous from the point of view of strength, and reflections in the porcelain part can be used and accentuated as a function of its thickness and its actual extent and the extent in relation to the crown. In the computer equipment, the coloring can be simulated with different color constellations placed on top of one another. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The abovementioned and other features of the inventions disclosed herein are described below with reference to the drawings of the preferred embodiments. The illustrated embodiments are intended to illustrate, but not to limit the inventions. The drawings contain the following figures: 
           [0018]      FIG. 1  shows a side cross-sectional view of parts of a jaw bone, gum, a ground tooth remnant, and, arranged on the remnant, a dental prosthesis in the form of a porcelain-coated crown, according to an embodiment of the present invention. 
           [0019]      FIG. 2  is a block diagram illustrating the connection of novel equipment to an existing and essentially fully automated manufacturing system of the PROCERA® type, according to another embodiment. 
           [0020]      FIG. 3  is an oblique top perspective view of a system for application of powder to a crown by means of a computer-controlled coloring device, and where upper parts of the crown are additionally shown enlarged, according to yet another embodiment. 
           [0021]      FIG. 4  is a top view of powder applied to a top face of the crown by the color printer according to  FIG. 3 . 
           [0022]      FIG. 5  is a side cross-sectional view illustrating build-up of layers on the crown and layered application of powder/color thereto, according to yet another embodiment. 
           [0023]      FIG. 6  is a flow chart of a manufacturing method for production of a porcelain-coated crown, according to yet another embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    With reference to  FIG. 1 , there is illustrated a human oral cavity  1  and a jaw bone  2 . The jaw bone  2  includes a gum  3 . A ground-down tooth or tooth remnant  4  and an embodiment of a dental prosthesis  5  are also shown. In the embodiment shown, the prosthesis  5  has the form of a crown  6  and a porcelain part or porcelain lining  7  on its outside. The inner surface  6   a  of the crown  6  can adjoin the outer surface  4   a  of the tooth  4  with great precision. 
         [0025]    The porcelain-coated crown  4  can be manufactured in an essentially fully automated manufacturing system  8 , according to the embodiment illustrated in  FIG. 2 . In accordance with an embodiment, information concerning the crown  6  and the porcelain part  7 , as shown in  FIG. 1 , is simulated, initiated, and/or transmitted to the system  8  with equipment  9 , which can be customer-based equipment. For example, the transmission can be via a public telephone network  10  and/or computer network (Internet). 
         [0026]    As shown in  FIG. 2 , the initiation and the transmission of information are symbolized by i 1 . The information can be received in the system  8  with information signals i 1 ′ which can be input to receiving equipment  11 . The receiving equipment  11  can convey the information onward to a unit  12  via transmission signals i 2 . 
         [0027]    According to another embodiment, the system  8  can confirm receipt with the customer location  9  and can be configured to transmit further information in this regard. Signals i 3  can therefore be transmitted from the system  8  to the customer  9  from the unit  11 . 
         [0028]    The system  8  is provided with a module unit  13  which is controlled by the control unit  12 . The control unit  12  can include a color selection  14  which can be passed to a unit  15  in the module unit  13 . The module unit  13  can also receive information regarding the crown  6  and the porcelain part  7 , such as the number of layers and the layer thicknesses, as has been symbolized by arrow  16  and part unit  17 . In some embodiments, parameters such as drying times, etc., can be affected by means of control information  18  and part unit  19 , etc. 
         [0029]    The final production in the system  8  can result in the prosthesis or prosthesis part  5 ′ which is returned to the customer location  9  in a known manner, such as by mail or recorded delivery, courier, etc. The customer location  9  can be included in the information provided to the computer equipment in a known manner. 
         [0030]      FIG. 3  is an oblique top perspective view of a system for application of powder to a crown by means of a computer-controlled coloring device, according to yet another embodiment. As shown in  FIG. 3 , the system can include computer equipment  20 , including a computer screen  21 , which can be used by a user (dental technician)  22  to initiate, simulate, and/or illustrate a crown  23  which is applied on a die  24 . The coloring device can be shown on the screen  21 , for example, by element number  25 . 
         [0031]    The computer equipment  20  can be interactive to allow the user  22  to prepare the crown  23 . The interaction between the computer equipment  20  and the user  22  can be wireless, for example by voice, as has been indicated by  26 . Alternatively, the interactive use can be via a keyboard (not shown) in a known manner. The information from the computer equipment  20  concerning the coloring can be sent digitally, as has been symbolized by  27 . The system can utilize operate with a number of base colors, and connection lines for these are shown by  28 . In this regard, the coloring device can be a color printer  29 , and can have directions of movement as illustrated by the arrows  30 . The color printer  29  can comprise a mixing unit  31  for mixing the colors to obtain the desired colouring or tint defined by the computer and has been illustrated by an arrow  32 . 
         [0032]    As shown in  FIG. 3 , a real die  24 ′ can be provided which corresponds to the die  24  illustrated on the screen  21 . In a corresponding manner, the crown  23  on the screen  21  is also shown as a real crown  23 ′. The die  24 ′ can be mounted on a tool  33  which can be rotatable about its longitudinal axis  34 , for example, in a counterclockwise direction  35 . The tool  33  and the color printer  29  can be moved relative to one another in the vertical direction, and the longitudinal axis  36  of the color printer  29  can adopt an inclination which is essentially approximately 45 degrees with respect to an outer surface  23   a  of the real crown  23 ′ during application of powder  37 ′ with the colors, optionally in (glycerol-based) liquid form. 
         [0033]    In one, the real crown  23 ′ can be produced as described below. The crown  23 ′ located inside the porcelain part  37  can be coated, in accordance with the lower part of  FIG. 3 , with color powder in different strips  38 ,  39  and quantities such that a natural-looking reproduction is obtained for the porcelain-coated crown when it is placed in the patient&#39;s mouth. Potential upward and downward movements of the tool  33  are indicated by the arrows  41 , and transfer of the position of the crown  23 ′ in cooperation with the color printer  29  to the position inside the porcelain part has been shown by the arrow  42 . 
         [0034]    With reference now to the embodiment shown in  FIG. 4 , a top surface  23   b  of a porcelain coated part  37  can be coated with different strips  38 ′,  39 ′ and  40 ′ of coloring. Likewise, different accumulations of colors  43 ,  44 ,  45  and  46  can be applied. The patterns can reproduce, together with the colors and the position of the strips, the overall coloring or tinting which is desired. The overall coloring can be based on tests and on experience which can be set out in charts or tables to be used in the different circumstances that arise. The extent of the top surface  23   b  which corresponds to the extent of the porcelain part  37  can be included in the coloring pattern. A further parameter is the height H which is shown in  FIG. 1  between the tops of the crown  23 ′ and of the porcelain part  37 , and is an important consideration for the final result. 
         [0035]      FIG. 5  is intended to show an embodiment wherein the crown  23 ′ has been built up with different layers  47 ,  48  and  49  with the aid of a color printer  29  (see  FIG. 3 ) or corresponding equipment. The color powder illustrated in  FIG. 4  can also be applied in different layers, of which two have been shown by  50  and  51  in  FIG. 5 . These layers  50 ,  51  can be applied through use of a so-called internal stain modifier. By combining the layers  50 ,  51  and placing these on top of one another, the result of the final coloring or tinting can be influenced. 
         [0036]    In an embodiment, the color printer  29  shown in  FIG. 3  can thus be used, on the one hand, for building up the crown  23 ′ and, on the other hand, for coloring the crown  23 ′. Alternatively, two different appliances can be used. The same technique can be used in the production or simulation of the crown  23 ′ on the computer screen  21 , and the simulation function can be program-controlled. 
         [0037]    With reference now to  FIG. 6 , there is illustrated a flow chart of a manufacturing method for production of a porcelain-coated crown, according to yet another embodiment In one embodiment of the method, in a first step  52  of the method, an order is placed at the production unit  8  (shown in  FIG. 2 ). The production unit  8  runs data which is forwarded to a production system. In a manufacturing step  53 , a crown is produced according to a previously known method, for example made of aluminium oxide or zirconium oxide. In a subsequent step  54 , an inner shape of the crown is milled out. Impression compound can then be introduced into the crown in a step  55 , and the impression is used to secure the crown on the die. 
         [0038]    In addition, as represented by step  56 , the crown can be mounted on the die. Thereafter, painting can be carried out in accordance with the above in a step  57 , and drying and/or hardening of the particular color in a step  58 . As in the previously known production procedure, this is followed by application of molten wax, milling of the outer shape in the hardened wax, and application of casting channels in the wax according to steps  59 ,  60  and  61 . In accordance with the above, the dental technician/person placing the order paints or colors the crown in a CAD environment. Color data can thereafter be coupled to the crown, and the information on this is transmitted digitally to the production unit  8  via the order in a manner known per se. The color printer at the production unit can apply the colors to the crown according to a pattern, as has been specified by the dental technician. The color printer is thus located at the production unit  8 . 
         [0039]    In accordance with the invention, a number of basic colors are used, for example five to fifteen, preferably nine or ten, and these can be dental base colors known to the dental technician, such as dark, brown, peach, caramel, white, violet, stain orange, etc. 
         [0040]    Although these inventions have been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present inventions extend beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the inventions and obvious modifications and equivalents thereof. In addition, while several variations of the inventions have been shown and described in detail, other modifications, which are within the scope of these inventions, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combination or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the inventions. It should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed inventions. Thus, it is intended that the scope of at least some of the present inventions herein disclosed should not be limited by the particular disclosed embodiments described above.