Abstract:
Method for producing a base part of a set of artificial teeth, or a set of artificial teeth having a base part, comprising the step of forming the base part by a rapid prototyping process, e.g. 3D lithography and, in particular, 3D laser lithography. Furthermore, the invention relates to a method of establishing a data set representing the shape of a base part of a set of artificial teeth, wherein a gum area or a model thereof is scanned and/or a model of a base part is scanned and/or the shape of the base part is simulated on a computer.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to the production of sets of artificial teeth including a base part, and to the production of such a base part itself. 
       BACKGROUND 
       [0002]    A set of artificial teeth is also referred to as “dentures”. Such a set of artificial teeth includes a base part which is normally gum-coloured and in which or on which artificial teeth are provided. Such base parts must each be custom made for each individual patient. The base part is fitted onto a gum area in which teeth are missing. It can be provided for an upper jaw or for a lower jaw. 
         [0003]    The sets of artificial teeth dealt with in the present connection are configured as removable sets of teeth. They are held on the gums e.g. by denture fixatives. 
       SUMMARY OF THE INVENTION 
       [0004]    It is the object of the present invention to improve the production of a set of artificial teeth and/or of a base part thereof. 
         [0005]    In accordance with one embodiment of the invention, a method is provided for producing a base part of a set of artificial teeth, or a set of artificial teeth having a base part, comprising the step of:
       forming the base part by a computer-aided production process, such as a rapid prototyping process, e.g. 3D lithography and, in particular, 3D laser lithography, a computer-aided milling process or some other removing or applying computer-aided production process.       
 
         [0007]    In accordance with another embodiment, a method is provided for establishing a data set representing the shape of a base part of a set of artificial teeth, or the shape of a set of artificial teeth including a base part, wherein
       a) a gum area or a model thereof is scanned and/or   b) a model of a base part is scanned and/or   c) the shape of the base part is simulated on a computer.       
 
         [0011]    In accordance with another embodiment, a machine-readable data carrier is provided comprising instructions which will cause a computer to execute a method as previously described. 
         [0012]    In accordance with another embodiment, a computer is provided with a machine-readable data carrier as previously described. 
         [0013]    According to the method for producing a (removable) set of artificial teeth, the base part is produced by a computer-aided production process, such as a rapid prototyping process. A rapid prototyping process is, quite generally, a primary forming method by means of which the workpiece is built (e.g. in layers) from shapeless or shape-neutral materials by utilizing physical and/or chemical effects. Such a rapid prototyping process can be e.g. the 3D lithography and, in particular, the 3D laser lithography. Other examples of rapid prototyping processes are stereolithography, selective laser sintering, laser generation, fused deposition modelling, laminated object modelling, 3D printing, contour crafting, multijet modelling or polyjet processes. 
         [0014]    In the case of 3D laser lithography, e.g. a synthetic resin is locally heated by a laser or a chemical reaction is caused by the laser light irradiation so that the liquid material solidifies. What can also be used here is melting a material in powder form which will then harden in a fused form during cooling. 
         [0015]    Computer-aided removing or applying production processes can be used as well. One example for a removing computer-aided process is computer-aided milling. In the case of applying computer-aided productions processes, layers of material, laminae or parts are applied one after the other so as to produce the workpiece. 
         [0016]    The liquid or powdery material used in a rapid prototyping process or in some other applying process can have e.g. a gum-coloured or a tooth-coloured hue already prior to the forming step. If the (rapid prototyping) process is only used for producing the base part, the desired hue, i.e. especially a gum-coloured hue, can already be achieved by such colouring without any further follow-up treatment. In addition, the hue achieved can also be changed during the rapid prototyping process, e.g. from gum-coloured to tooth-coloured and/or from a first gum colour to one or a plurality of other gum colours and/or from one tooth colour to one or a plurality of other tooth colours. 
         [0017]    On the other hand, it is also possible that a base part produced by a (rapid prototyping) process is fully or partly redyed so as to achieve a desired hue, in particular a gum-coloured hue, or shades of colour, colour gradients etc. 
         [0018]    Furthermore, a method will be of advantage in the case of which also teeth of the set of artificial teeth are produced by the (rapid prototyping) process. These teeth can be formed integrally with the base part (but possibly with at least two different colours according to an advantageous embodiment) or they can also be produced separately of said base part. These teeth produced by the (rapid prototyping) process can have applied thereto one or a plurality of colour coats and/or one or a plurality of other layers increasing e.g. the wear resistance. Colour coats can also be applied to the base part. 
         [0019]    Since the demands on the material of the base part and on the material of the artificial teeth are normally markedly different and since in particular the teeth must fulfil very high requirements as regards breaking and wear resistance, it will also be of advantage when prefabricated artificial teeth are provided for the set of artificial teeth. These prefabricated teeth can be connected to the base part in an appropriate manner. They can, for example, also be inserted. For the purpose of connection, an adhesive can be provided and/or mechanical connection means, such as a screw, a thread, a pin, a bayonet joint or other mechanical connection means. 
         [0020]    Possible connection means on the base part for fastening the artificial teeth or tooth veneers can preferably be formed integrally with the base part. It will be of advantage to produce them by one and the same rapid prototyping process which is also used for producing the base part itself. 
         [0021]    According to an advantageous embodiment, the shape of the base part is modelled by a computer. For this purpose, e.g. the shape of the gum area to which the set of artificial teeth is to be fitted can be scanned directly, or a model of this gum area can be scanned. The shape of the gum area can then be used for modelling the shape of the base part. 
         [0022]    On the other hand, it is also possible that the shape of the base part is determined through a model of the base part. In this case, e.g. a model of the base part is built onto a model of the gum area (e.g. with wax) and is then recorded e.g. by scanning so that a data set will be provided, which represents the shape of the model of the base part. 
         [0023]    In this connection, it will especially be advantageous to use a method in the case of which the inner shape of the base part is determined on the basis of the shape of the gum area (or of a model thereof) and the outer shape is either simulated by a computer or determined by scanning a model of a base part. 
         [0024]    The shape of the base part and/or the shape of the set of artificial teeth and/or one or more data sets corresponding to these shapes, are permanently archived according to an advantageous embodiment. It will thus e.g. be possible to produce later on, when the set of artificial teeth is worn-out, a new, but identical set of artificial teeth. This can be done e.g. on demand of a patient (or of the patient&#39;s dentist). The demand can e.g. be received by Internet, i.e. the new set of artificial teeth can be ordered via the Internet. 
         [0025]    The invention also relates to a method of establishing a data set representing the shape of a base part of a set of artificial teeth. 
         [0026]    In this respect, each of the above-mentioned method steps can be used. For example, a gum area and/or a model thereof can be scanned. Furthermore, a model of a base part can be scanned or the shape of the base part can be simulated on a computer. 
         [0027]    A data set for producing a base part can either be transmitted locally to a rapid prototyping device or to some other computer-aided production device or it can be sent through remote data transmission to a production centre, which will then use said data set for executing a rapid prototyping process or some other computer-aided production process so as to produce the base part. 
         [0028]    In addition, machine-readable data carriers and computers for executing the methods referred to hereinbefore or hereinbelow are provided. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    Preferred embodiments of the invention will be explained making reference to the figures enclosed, in which: 
           [0030]      FIG. 1  shows a set of artificial teeth; 
           [0031]      FIG. 2  shows various variants of base parts; 
           [0032]      FIG. 3  shows various sectional views of sets of artificial teeth; 
           [0033]      FIG. 4  shows a schematic representation of components for executing methods or method steps. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]      FIG. 1  shows a set of artificial teeth  1  comprising a base part  2  and artificial teeth  3 . The base part  2  should preferably be gum-coloured and the teeth  3  should preferably be tooth-coloured, i.e. they should essentially be held in a shade of white. 
         [0035]    Such a set of artificial teeth can be provided for the upper jaw or the lower jaw. Whereas  FIG. 1  shows a full denture, in the case of which all the teeth of one jaw are replaced, the denture provided may also only be a partial denture, which covers only part of the jaw and replaces thus only part of the teeth. 
         [0036]    The teeth  3  can be formed integrally with the base part  2 . They may, however, also be implemented such that they are not integral with the base part  2 . The base part  2  itself is preferably a one-piece component, it may, however, also be implemented as a two-, three- or multi-piece component. 
         [0037]      FIG. 2   a  shows a base part  2   a  having provided therein openings or recesses  4  into which the artificial teeth are inserted. Furthermore, a fastening means  5  is shown in the area of the molars, said fastening means  5  being preferably formed integrally with the base part  2   a . More detailed explanations to the fastening means are contained in the description relating to  FIG. 3 . 
         [0038]    In  FIG. 2   b  a base part  2   b  is shown, in which recesses  4  for receiving therein the respective artificial teeth are provided. Special additional fastening means  5  are here not provided. 
         [0039]    In  FIG. 3  various sections are shown, said sections being made at the location indicated in  FIG. 2   a  under III.  FIG. 3   a  shows a sectional view of a base part  2   c  whose lower surface (inner side) is formed irregularly depending on the gum area to which the set of artificial teeth is to be fitted. The lateral outer surface is designed according to aesthetical and stability aspects. The upper side of the base part  2   c  has arranged thereon an artificial tooth  3   c  whose lower end is provided with a recess into which the fastening means  5  can be inserted. The artificial tooth  3   c  can e.g. be glued on. By means of the cubic fastening means  5 , a rotational displacement of the artificial tooth  3  can be prevented effectively and the position of the artificial tooth  3   c  can be defined precisely, when said tooth is glued on. 
         [0040]    In  FIG. 3   b  an alternative embodiment is shown, in the case of which an artificial tooth  3   d  is provided with a female thread  8  which is engaged by a screw  7 . The base part  2   d  has provided therein a recess  6  accommodating the head of the screw  7  in the fixed condition. The opening  6  can also be filled, when the screw  7  has been inserted and tightened. 
         [0041]      FIG. 3   c  shows a variant in the case of which a base  9  is provided on the upper surface of the base part  2   e , said base  9  having only attached thereto a tooth veneer  3   e . This artificial tooth veneer  3   e  exhibits an appropriate hue for teeth and guarantees high wear resistance. Materials that can be used here are e.g. porcelain materials, ceramic materials or the like. The base used for a tooth veneer has a volume of at least 30%, 50%, 70%, 80% or 90% of the volume occupied and/or enclosed by the veneer. 
         [0042]      FIG. 3   d  shows a further variant according to which a round recess  10 , into which an artificial tooth  3   f  can be glued, is provided on the upper side of the base part  2   f.    
         [0043]    The variant according to  FIG. 3   d  corresponds approximately to the base part shape according to  FIG. 2   b.    
         [0044]    The respective shapes of the recess  4  and/or of the fastening means  5 ,  6 ,  9 ,  10  can be determined on the basis of data that are known in advance. In the case of prefabricated teeth, the shape of the tooth is known so that the required shape of the base part is known as well. This shape is preferably stored in an electronic library or file or database and can be retrieved for modelling the base part. 
         [0045]    The shape required for the respective teeth can be incorporated in a data set describing the base part; this data set can have been created (e.g.) by scanning a model or by modelling a base part on the computer. 
         [0046]      FIG. 4  shows a scanner  13  (which is here, by way of example, an optical scanner) that can be used for scanning a shape of a model or of a gum area. In  FIG. 4 , a model  12  is provided, which has on the upper side thereof a region  15  representative of the shape of a gum area. This region can be scanned with the scanner  13  (cf. exemplarily the light beam  14 ). The data of the scanner  13  can be transmitted to a computer  16 . For this purpose, a data connection  20  (cable-bound or wireless data connection) is provided. On the monitor of the computer  16  a data set  17  is shown, which represents the shape of the gum region  15 . Furthermore, a data set  18  which represents the shape of a base part is shown on the monitor. Taking as a basis the data set  17 , this data set  18  can be created on the computer by simulation. The inner or lower side  21  of the data set  18  (i.e. the region which will face the gum area or come into contact therewith) is preferably formed on the basis of the acquired data  17 . This will lead to an optimum fitting accuracy. The thickness of the base part and, consequently, its stability is determined by the outer side  22 . In the case of the model  12 , a base part can, however, also be modelled onto the region  15 . Said model  12  can be scanned by the scanner  13  and the shape for the outer side  18  of the base part can be developed in this way. Such data acquired by scanning can be reworked by means of a computer (e.g. modification of the inner or outer side, insertion of shaped elements for artificial teeth, such as recesses or fastening means, etc.). 
         [0047]    A particularly advantageous method is so conceived that the region  15  is first scanned for acquiring the data for the inner side  21  of the base part and that the outer side  22  is then either simulated on the computer  16  or a model is modelled onto the region  15  and scanned so as to obtain the data for the outer side  22 . Also combinations of these last two method variants are possible by scanning e.g. a model of the base part, said model being, however, subsequently reworked on the computer. Such reworking can especially be used for adding e.g. the fastening means for the artificial teeth. 
         [0048]    A data set  18 , which represents the shape of a base part, can be transmitted with data transmission means  19 , e.g. an Internet connection, through remote data transmission to a production centre for base parts. The data set  18  may, however, also be transmitted locally to a rapid prototyping system which will then produce an appropriate base part. 
         [0049]    The data describing the parts produced (base part, teeth, set of artificial teeth, etc.), or other data that can be used for producing said parts, can be archived for a long time (one, two, three, four, five or more years). This allows the use of said data for the production of a second or further set of artificial teeth. The archiving does preferably not take place on the computer  16 , but on a mass data storage device, such as a recordable CD, DVD, a magnetic tape, a data store or the like. 
         [0050]    A base part of the type shown in  FIG. 2   b  can have applied thereto one or a plurality of colour coats. Desired colour gradients, hues and shades of colour can be accomplished in this way, as can e.g. be done by a dental technician. 
         [0051]    Colour coats or layers increasing the wear resistance can also be applied to the artificial teeth or the base (cf.  FIG. 3   c ) by a dental technician.