Abstract:
A method for creating a digital model of a denture for a patient, where the denture includes a gingival part and artificial teeth, includes obtaining digital models of artificial teeth representing the artificial teeth; obtaining a 3D scan comprising a digital representation of at least part of the patient&#39;s existing gingiva; digitally modeling a gingival part of the digital model of the denture using the 3D scan and the digital artificial teeth; digitally determining a first offset defining a first thickness of a first portion of the gingival part of the digital model of the denture that extends from the digital representation of the at least part of the patient&#39;s existing gingiva; and digitally determining a second offset defining a second thickness of a second portion of the gingival part of the digital model of the denture that extends from the digital artificial teeth.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of U.S. Ser. No. 13/877,064, which is a national stage application of PCT/DK11/50370, filed on Sep. 30, 2011, and which claims the priority of U.S. 61/388,956, which was filed on Oct. 1, 2010, and DK Application No. PA 2010 00893, which was filed on Oct. 1, 2010. U.S. Ser. No. 13/877,064; PCT/DK11/50370; U.S. 61/388,956; and DK Application No. PA 2010 00893 are all incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention generally relates to a method for modeling and manufacturing a denture for a patient. In particular the invention relates to computer-implemented modeling. 
       BACKGROUND 
       [0003]    US2009287332 discloses a system for fabricating at least a portion of a denture. The system includes a three-dimensional scanning device for scanning a surface of a denture template, and a computer-readable medium including a computer program for receiving data from the scanning device, creating a 3-dimensional model of the surface, and optionally modifying the 3-dimensional model and/or adding features to the 3-dimensional model. The system also includes a fabricator for creating the at least the portion of the denture, from a selected material, based on the 3-dimensional model. The fabricator may be a device including a lathe, or a rapid prototyping machine. There is also provided a method for fabricating at least a portion of a denture. US2007009852 discloses a denture comprising a denture plate comprising a support member having an approximately U-shape base, a labial wall extending from said base and a lingual wall extending from said base; said base, labial wall and lingual wall forming an approximate U-shape cross-section along an imaginary vertical plane to form a channel; and a deformable member extending through the channel to separate the channel into a gum receiving section and a fitting section; and, a false teeth assembly including a plurality of false teeth secured to said base. 
         [0004]    US2006040236 discloses a method of creating a dental restoration customized to the clinical needs of a patient comprising the steps of: preparing a patient&#39;s existing dental structures for digital modeling wherein the existing dental structures may comprise implant anchors, soft tissue, jawbone, existing teeth, and an existing denture; making a first three-dimensional digital model of the dental restoration wherein the first three-dimensional digital model comprises the implant anchors, soft tissue form, any existing teeth, and the planned position of one or more artificial teeth; creating a second three-dimensional digital model of the dental restoration wherein the second three-dimensional digital model comprises a substructure for attaching to the patient&#39;s existing dental structures and for retaining the artificial teeth; producing the substructure from the second three-dimensional digital model; positioning and securing the artificial teeth on the substructure; and securing the substructure to the patient&#39;s existing dental structures. 
         [0005]    It remains a problem to provide an improved method for modeling and manufacturing of dentures. 
       SUMMARY 
       [0006]    Disclosed is a method for modeling and manufacturing a denture for a patient, where the denture comprises a gingival part and artificial teeth, wherein the method comprises the steps of:
       providing a 3D scan comprising at least part of the patient&#39;s oral cavity;   virtually modeling at least part of the denture using the 3D scan;   obtaining virtual teeth to represent the artificial teeth;   virtually modeling at least one of the virtual teeth to obtain a set of modeled virtual teeth;   manufacturing the modeled virtual teeth in a first material;   manufacturing the gingival part in a second material; and   manufacturing at least part of the denture by means of computer aided manufacturing (CAM).       
 
         [0014]    It is an advantage that the virtual teeth representing artificial teeth and/or the gingival may be modeled using a 3D scan comprising at least part of the patient&#39;s oral cavity. Furthermore, the virtual teeth representing the artificial teeth are virtually modeled before manufacturing of the denture. The artificial teeth may be selected from a number of virtual pre-designed teeth, and these pre-designed teeth may then be modeled to fit the patient or meet and satisfy the patient&#39;s requests and wishes. The virtual teeth may correspond to real, physical, pre-manufactured, artificial teeth. Thus the artificial teeth may be selected by the patient at the dentist&#39;s clinic either by seeing the physical artificial teeth in real life or by seeing the virtual pre-designed teeth corresponding to these physical teeth on a computer screen. 
         [0015]    It is a further advantage that the denture can be virtually modeled, since this may provide a denture of higher quality, and the cost as well as the time needed to make the denture may be reduced. By using a 3D scan comprising the patient&#39;s oral cavity the quality of the denture may also be improved. The 3D scan comprising at least part of the patient&#39;s oral cavity comprises any teeth still present in the mouth, and it may be a 3D scan of an impression of the patient&#39;s teeth, it may be a 3D scan of a physical model of the patient&#39;s teeth, and/or it may be a 3D scan made directly in the mouth of the patient, i.e. an intra oral scan. 
         [0016]    Providing the 3D scan may mean acquiring the 3D scan by performing the scanning, or retrieving the 3D scan from a digital file on a computer. The 3D scan may be obtained at the same time and place as the modeling and manufacturing are performed, or the 3D scan may be obtained separately from the modeling. Furthermore, the modeling and manufacturing may be performed at the same physical location, or modeling and manufacturing may be performed at different physical locations. 
         [0017]    Furthermore, the order in which the different steps are performed can be different than the order above. However logically, the modeling steps will be performed before the manufacturing steps. But the step of obtaining virtual teeth to represent the artificial teeth may for example be performed before the step of virtually modeling at least part of the denture using the 3D scan. 
         [0018]    The artificial teeth may be denoted a teeth part of the denture. 
         [0019]    As well as virtual teeth represent the artificial teeth, a virtual gingival part may be defined to represent the gingival part of the denture. 
         [0020]    When manufacturing the modeled virtual teeth, manufactured modeled teeth is obtained. It may also be denoted manufactured modeled virtual teeth. 
         [0021]    The virtual modeling of the denture in general, and the virtual modeling of the virtual teeth and the gingival part in particular, are performed by means of computer aided designing (CAD). 
         [0022]    Many different types of dentures exist, such as:
       full denture;   partial denture;   denture comprises one or more implants;   removable denture;   fixed denture;   fixed partial denture;   removable partial denture;   bridge with or without veneering in the form of porcelain or composite;   bar with or without implants, artificial teeth etc;   dental prosthesis, e.g. on a bar or on teeth;   denture comprising or being attached to an implant bar, which is adapted to be attached to the jaw bone in the mouth of a patient.       
 
         [0034]    Furthermore, bar and bridge types may be standard types such as Dolder, Hader, Hybird, Canada, Wrap-around, Primary etc., and bars and bridges may be free-form design or custom shapes. 
         [0035]    Dentures are different from restorations or prostheses, because a denture replaces missing teeth, and there will thus be artificial teeth and artificial gingival in a denture, whereas a restoration for example in the form of a crown or a bridge will not comprise artificial gingival or artificial teeth, but crowns and in the case of a bridge, one or more pontics. The processes for designing and manufacturing a denture are thus different from when designing and manufacturing restorations and prostheses. 
         [0036]    In some embodiments the method comprises virtually modeling attachment of the artificial teeth in the gingival part. 
         [0037]    Virtual Modeling of the Attachment of Artificial Teeth in the Gingival Part 
         [0038]    According to an aspect, disclosed is a method for modeling and manufacturing a denture for a patient, where the denture comprises a gingival part and artificial teeth, wherein the method comprises the steps of:
       providing a 3D scan comprising at least part of the patient&#39;s oral cavity;   virtually modeling at least part of the denture using the 3D scan;   obtaining virtual teeth to represent the artificial teeth;   virtually modeling at least one of the virtual teeth to obtain a set of modeled virtual teeth;   virtually modeling attachment of the artificial teeth in the gingival part;   manufacturing the modeled virtual teeth in a first material;   manufacturing the gingival part in a second material; and   manufacturing at least part of the denture by means of computer aided manufacturing (CAM).       
 
         [0047]    It is an advantage that the attachment of the artificial teeth in the gingival part is virtually modeled or designed, because when also the attachment of the artificial teeth on the gingival part is virtually designed or modeled, then the whole process of designing a denture can be performed virtually or digitally, and the manufacturing process may then also be performed entirely automatic, for example without requiring any manual manufacturing or any manufacturing performed by persons. 
         [0048]    It is an advantage to virtually design the attachment of the artificial teeth in the gingival part, since this may provide improved aesthetics and functionality of the denture, because the attachment is designed while designing the rest of the denture, and the manufacturing of the attachment may also be manufactured while the rest of the denture is manufactured. 
         [0049]    It is an advantage also to virtually design the attachment of the artificial teeth in the gingival part as well as designing the other parts of the denture, since virtually designing the attachment may provide a better, firmer, stronger, more solid, robust and reliable attachment of the artificial teeth. 
         [0050]    It is an advantage that in the design process it is ensured that the designed teeth actually can also be physically attached in the designed gingival, since the design of the attachment can be visually and computationally checked and verified that it can physically be implemented and executed in the manufactured denture. 
         [0051]    Attachment Means and Structures 
         [0052]    In some embodiments the method comprises virtually modeling means for attachment of the artificial teeth in the gingival part. 
         [0053]    In some embodiments the method comprises virtually modeling physical structures for attaching the artificial teeth in the gingival part. 
         [0054]    In some embodiments the method further comprises selecting predesigned physical structures in a digital library for attaching the artificial teeth in the gingival part. 
         [0055]    Methods for Virtually Modeling the Attachment of Artificial Teeth in the Gingival Part 
         [0056]    In some embodiments the virtual modeling of the attachment of the artificial teeth in the gingival part comprises mathematically subtracting a first shape from a second shape. 
         [0057]    In some embodiments the first shape is the artificial teeth and the second shape is the gingival part. 
         [0058]    In some embodiments the virtual modeling of the attachment of the artificial teeth in the gingival part comprises offsetting at least a part of the artificial teeth and/or at least part of the gingival part. 
         [0059]    In some embodiments the virtual modeling of the attachment of the artificial teeth in the gingival part comprises a cavity operation. 
         [0060]    In some embodiments the cavity operation comprises subtracting the shape of the artificial teeth which is configured for being arranged in the gingival from the gingival part. 
         [0061]    It is an advantage to virtually design the artificial teeth and the gingival part such that the area in the gingival part where the artificial teeth shall be arranged is designed or modeled to match the area on the artificial teeth which shall be arranged in the gingival part. For ensuring an effective and stable attachment the shape of the area in the gingival part where the artificial teeth are configured to be arranged may match, fit, correspond, resemble the shape of the area on the artificial teeth which are configured to be arranged in the gingival part. Thus the adjacent 3D surfaces of the contact area on an artificial tooth and of the contact area in the gingival part may be designed to exactly match or fit each other. 
         [0062]    The contact area on the artificial tooth/teeth may be designed and then the design may be copied or transferred to the contact area in the gingival part. Alternatively, the contact in the gingival part may be designed and then the design may be copied or transferred to the contact area on the artificial tooth/teeth. 
         [0063]    Alternatively and/or additionally, a pre-designed, standard contact area may be selected from a digital library in a computer software program, and the design of this selected contact area may then be applied or transferred to the contact area in the gingival part and/or to the contact area on the artificial teeth. 
         [0064]    Holes in Gingival Part to Receive Teeth 
         [0065]    In some embodiments the method further comprises modeling and manufacturing holes in the gingival part to receive the manufactured teeth. 
         [0066]    The Physical Design of the Attachment 
         [0067]    In some embodiments the attachment of the artificial teeth in the gingival part is obtained by means of performing undercuts in the gingival part and press-fitting the artificial teeth into the holes and undercuts in the gingival part. 
         [0068]    In some embodiments the attachment of the artificial teeth in the gingival part is obtained by means of interlocking features. 
         [0069]    In some embodiments the interlocking features are arranged in the holes in the gingival part and/or in the area of the artificial teeth which is adapted to be arranged in the holes in the gingival part. 
         [0070]    In some embodiments the interlocking features are ball-shaped. 
         [0071]    In some embodiments the interlocking features are adapted to be pushed in such that they align with the surface they are arranged in, and where the interlocking features are then adapted to be pushed out when the artificial teeth are arranged in the holes in the gingival part for locking the artificial teeth in the gingival part. 
         [0072]    In some embodiments the interlocking features are adapted to be pushed in such they align with the surface they are arranged in, when pressure is applied on the interlocking features, and when pressure is relieved from the interlocking features they are adapted to be pushed out. 
         [0073]    In some embodiment the attachment of the artificial teeth in the gingival part is performed by means of gluing the artificial teeth into the holes of the gingival part. 
         [0074]    In some embodiments the artificial teeth are attached in the gingival part by means of providing a bore in the area of the artificial teeth which is adapted to be arranged in the hole in the gingival part, and arranging a bar in the bore, where the bar is adapted to extend to the gingival part for retaining the artificial teeth in the gingival part. 
         [0075]    In some embodiments the artificial teeth are attached in the gingival part by fastening means. 
         [0076]    In some embodiments the fastening means are screws. 
         [0077]    Manufacturing the Attachment 
         [0078]    In some embodiments the method further comprises manufacturing attachment means for attaching the artificial teeth in the gingival part. 
         [0079]    According to an aspect of the present invention a method is disclosed for modeling a denture for a patient, where the denture comprises a gingival part and artificial teeth, wherein the method comprises the steps of:
       providing a 3D scan comprising at least part of the patient&#39;s oral cavity;   virtually modeling at least part of the denture using the 3D scan;   obtaining virtual teeth to represent the artificial teeth;   virtually modeling at least one of the virtual teeth to obtain a set of modeled virtual teeth.       
 
         [0084]    Furthermore, according to an aspect of the present invention, a method is disclosed for manufacturing a denture for a patient, where the denture comprises a gingival part and artificial teeth, where a 3D scan comprising at least part of the patient&#39;s oral cavity is provided, where at least part of the denture is virtually modeled using the 3D scan; where virtual teeth are obtained to represent the artificial teeth; where at least one of the virtual teeth is virtually modeled to obtain a set of modeled virtual teeth, where the method comprises the steps of:
       manufacturing the modeled virtual teeth in a first material;   manufacturing the gingival part in a second material; and   manufacturing at least part of the denture by means of computer aided manufacturing (CAM).       
 
         [0088]    In some embodiments the artificial teeth are manufactured in a synthetic polymer material, such as acrylic. 
         [0089]    Acrylic means a material consisting of or comprising or derived from acrylic. 
         [0090]    In some embodiments the first and the second material are the same. 
         [0091]    In some embodiments the first and the second material are different. 
         [0092]    In some embodiments the method further comprises obtaining the virtual teeth by algorithmic shaping. 
         [0093]    It is an advantage since the fitting and aesthetics of the artificial teeth may be improved, when the virtual teeth are obtained by algorithmic shaping. The algorithmic shaping may be based on the existing teeth, gingival etc. in the patient&#39;s mouth. 
         [0094]    In some embodiments the method further comprises obtaining the virtual teeth by selection from among a number of virtual, pre-designed teeth. Thus when virtually modeling at least one of the selected, virtual, pre-designed teeth, a set of adjusted pre-designed teeth will be obtained. 
         [0095]    In some embodiments the method further comprises selecting the pre-designed teeth from a library of template teeth. 
         [0096]    The library may be the user&#39;s or operator&#39;s own library, a library from certain manufacturers of artificial teeth etc. Alternatively and/or additionally the artificial teeth are from a user&#39;s own design of teeth for a denture, from an existing restoration etc. 
         [0097]    In some embodiments the method further comprises selecting the pre-designed teeth based on shape and/or color. 
         [0098]    In some embodiments the virtual teeth correspond to pre-manufactured teeth. 
         [0099]    Thus the virtual teeth exist as or have corresponding pre-manufactured teeth. The virtual teeth and the corresponding physical pre-manufactured artificial teeth may be from a manufacturer of artificial teeth, such as Ivoclar, Heraeus, Dentsply, Merz, Vita etc. 
         [0100]    Thus the result of the virtual modeling of the virtual teeth will be manufactured by physically modeling the pre-manufactured teeth. This may be performed using a CAD-CAM milling or grinding machine. 
         [0101]    Alternatively, if using e.g. a ceramic system such as e.max, all the artificial teeth are manufactured from scratch, and no pre-manufactured teeth are used. The teeth will then be fully customizable teeth based on a design. Thus in some embodiments the artificial teeth are adapted to be manufactured from scratch using no pre-manufactured teeth. 
         [0102]    In some embodiments at least the pre-manufactured teeth are made of a material which is adapted to be grinded and/or milled. 
         [0103]    In some embodiments the method further comprises automatic grinding or milling the pre-manufactured teeth according to the modeled virtual teeth by means of a CAM machine. 
         [0104]    Alternatively, pre-manufactured teeth may be used directly in the denture without modifying them, if the design of the pre-manufactured teeth fit well to the patient. However, normally the virtual teeth will be modeled somehow in order to fit the present case. 
         [0105]    In some embodiments the method further comprises manufacturing the modeled virtual teeth from pre-manufactured teeth corresponding to the virtual teeth. 
         [0106]    In some embodiments the method further comprises manufacturing the modeled virtual teeth from blanks. 
         [0107]    The blanks may be e.max ceramic blanks or other suitable blanks. 
         [0108]    In some embodiments the method further comprises manufacturing the modeled virtual teeth by printing. 
         [0109]    It is an advantage that the teeth of the denture may be manufactured by means of 3D printing, since 3D printing may provide that the artificial teeth are of good quality both aesthetically and functionally. Furthermore, if both the teeth part and the gingival part of the denture are printed, then the manufacturing of the denture may be performed fast and with a good result. Even though both the teeth part and the gingival part are printed, they may be printed in different materials, e.g. a hard material for the teeth part and a soft material for the gingival part, and/or in different colors, such that the teeth part are printed in a white material and the gingival part are printed in a pink/red material resembling the natural color of the gingival. 
         [0110]    In some embodiments the method further comprises providing the virtual teeth to have a size so big, that during manufacturing of the modeled virtual teeth, material is only removed from and not added to the corresponding pre-manufactured teeth. 
         [0111]    It is an advantage since hereby a grinding or milling machine can be used, since material should only be removed from the pre-manufactured teeth, and a milling or grinding machine is adapted to cut away material. 
         [0112]    When modeling the gingival part of the denture, different things are taken into account. When a patient has no or only some teeth in the mouth, the gingival and the underlying bone structure will disintegrate, where there are no teeth. Thus the gingival part of the denture must be bigger in those areas where the patient has been without teeth for a while, since the gums have collapsed in these areas. 
         [0113]    In some embodiments, the method further comprises modeling the gingival part based on a template gingival. 
         [0114]    In some embodiments the method further comprises modeling the gingival part based on a determined occlusal plane. 
         [0115]    The occlusal plane may be determined based on the position of the retromolar space of the mouth and on the position corresponding to a center point between the two lower central teeth. The occlusal plane may furthermore be determined based on other specific points, teeth, distances etc of the patient&#39;s mouth. 
         [0116]    In some embodiments the method further comprises determining where the edge of the gingival part should end at the existing, physiological gingival. This may be determined based on a template gingival or it may be marked manually. The edge of the gingival part should end at a place such that it looks natural. 
         [0117]    In some embodiments the method further comprises determining where the gingival part should end at the teeth. 
         [0118]    This may be determined based on different templates, such as a low-gingival template, a high-gingival template and a normal-gingival template. It may also the marked manually on the teeth. The edge of the gingival part should end at a place such that it looks natural. 
         [0119]    In some embodiment the method further comprises using offsetting, lofting and smooth transitioning to model the gingival part relative to the existing physiological gingival and the virtual teeth. 
         [0120]    Thus points may be marked on the teeth for indicating that the gingival part should end there, a first offset of the gingival part from the existing gingival may be determined, a second offset of the gingival part from the teeth may be determined, a smooth transition connecting the first offset from the existing gingival and the second offset from the teeth may be performed using a lofting operation. 
         [0121]    Offsetting may be defined as that an offset within an array or other data structure object is an integer indicating the distance or displacement from the beginning of the object up until a given element or point. 
         [0122]    Lofting is a drafting technique to draw curved lines. The technique can be used to perform bending of an object, in this case a virtual object, so that it passes over three non-linear points and scribing the resultant curved line, or plotting the line using computers or mathematical tables. 
         [0123]    In some embodiments the method further comprises offsetting the gingival part around the virtual teeth. 
         [0124]    By offsetting the gingival part around the virtual teeth and finally around the manufactured teeth, the gingival part will look more natural since this offsetting corresponds to how the real physiological gingival looks around the teeth. 
         [0125]    In some embodiments the method further comprises applying stipple wax pattern on the gingival part. 
         [0126]    By applying stipple wax pattern the gingival part will look more natural. However it may be more difficult to clean the denture when there are offsets and stipple wax pattern because the gingival part will be more bulky, and therefore only the front part of the gingival part may be applied with the stipple wax pattern, while the part of the gingival hidden by the lips and the mouth may be smooth for easier cleaning. 
         [0127]    In some embodiments the method further comprises arranging the position of the virtual teeth in the gingival part based on predetermined rules or criteria. 
         [0128]    For example the vertical distance between where the real gingival ends in the mouth and where the teeth ends can be a certain distance. 
         [0129]    Furthermore, mirroring and symmetry may be used to model the gingival part as well as the teeth. 
         [0130]    In some embodiments the method further comprises that at least the gingival part of the denture is manufactured by means of 3D printing. 
         [0131]    In some embodiments the method further comprises that at least the gingival part is manufactured by means of milling. 
         [0132]    It is an advantage since milling may be easiest to use when undercuts should be manufactured on the gingival. 
         [0133]    In some embodiments the method further comprises modeling and manufacturing holes in the gingival part to receive the manufactured teeth. 
         [0134]    In some embodiments the method further comprises manufacturing the gingival part and the manufactured teeth separately. 
         [0135]    In some embodiments the method further comprises assembling the manufactured teeth and the gingival part automatically after the manufacturing, whereby the manufactured teeth are arranged into the corresponding holes in the gingival part. 
         [0136]    In some embodiments the method further comprises manufacturing the modeled virtual teeth and the gingival part collectively. 
         [0137]    A collective manufacturing may be performed if both the teeth part and the gingival part of the denture are manufactured by means of for example milling or 3D printing. 
         [0138]    In some embodiments the method further comprises providing the virtual teeth to have a size so big, that during modeling of the virtual teeth, material is only removed from and not added to the virtual teeth. 
         [0139]    It is an advantage because hereby when the teeth are manufactured from pre-manufactured teeth, the pre-manufactured teeth can be adjusted in a milling or grinding machine, because material should only be removed. 
         [0140]    In some embodiments the virtual teeth are a composed set of teeth comprising a number of teeth arranged spatially relative to each other forming a high functional and aesthetic composition. 
         [0141]    A high functional composition or combination may be a composition with a good occlusion, bite etc. A high aesthetic composition may be a composition which is visually pleasing. 
         [0142]    In some embodiments the method further comprises collectively modifying one or more parameters of the teeth in the composed set of teeth. 
         [0143]    In some embodiments the denture is adapted to be attached to dental implants and/or on dental implant bars or bridges. 
         [0144]    The dental implant bars or bridges may be the primary structure, and the denture may be the secondary or tertiary structure. 
         [0145]    Alternatively, the denture is adapted to be supported by existing teeth and/or the real gums in the patient&#39;s mouth. 
         [0146]    In some embodiments the method further comprises modeling the denture and the dental implants and/or dental implant bar or bridge to fit each other. 
         [0147]    In some embodiments the method further comprises modeling the attachment means for attaching the denture and the dental implants and/or dental implant bar or bridge to fit each other. 
         [0148]    In some embodiments the method further comprises modeling pins on the dental implant bridge and corresponding holes in the denture to fit each other. 
         [0149]    The pins may be virtually moved to fit in the virtual teeth of the denture. The pins may be free-form shaped or selected from a library or from default templates. The holes may be generated automatically based on the arrangement of the pins. There may also be a cement space in the hole where the pin does not reach down. Pins may be used in a denture for providing extra strength of the denture. 
         [0150]    In some embodiments the method further comprises obtaining the dental implant pins and automatically generating the corresponding holes in the denture to fit the dental implant pins. 
         [0151]    The pins may be modeled, selected from a library of dental implant pin templates, or selected from among a number of default pin templates. 
         [0152]    In some embodiments the holes in the denture are manufactured according to the corresponding pins in the bridge. 
         [0153]    In some embodiments the method further comprises modeling dental implant pins and holes in the denture based on holes in the pre-manufactured teeth. 
         [0154]    The holes may be standard holes in the pre-manufactured teeth, they may be modeled, selected from a library of holes templates, or selected from among a number of default holes templates. 
         [0155]    In some embodiments the pins in the bridge are manufactured according to the corresponding holes in the gingival. 
         [0156]    In some embodiments the denture is adapted to be attached to a partial removable framework. 
         [0157]    Thus the denture may be attached at least partly to a partial removable framework, and e.g. partly to existing teeth in the mouth. 
         [0158]    In some embodiments the method further comprises collectively modeling the partial removable framework and the denture comprising the manufactured teeth and the gingival part. 
         [0159]    In some embodiments when the gingival part of the denture is manufactured separately by 3D printing, then the method further comprises separating the gingival part and/or the partial removable framework into at least two pieces, such that the gingival part and the partial removable framework are adapted to be assembled and attached to each other. 
         [0160]    In some embodiments the method further comprises virtually blocking out the space between the partial removable framework and the existing gingival. 
         [0161]    The space may be virtually blocked out such that when manufacturing the gingival part based on the CAD design, the gingival part will not extend between the partial removable framework and the real gingival. 
         [0162]    When manufacturing a denture, traditionally a try-in is made and tested in the patient&#39;s mouth before producing the final denture. The reason for this is that the material which the denture is made of is a hard material for ensuring maintenance of the shape, but when testing and adjusting it is easier to use a soft material, and the try-in is thus made in a deformable material. 
         [0163]    In some embodiments the method further comprises the steps of:
       manufacturing a try-in comprising at least a try-in gingival;   testing the try-in in the patient&#39;s mouth;   if the try-in does not fit, adjusting the try-in to fit in the patient&#39;s mouth.       
 
         [0167]    The try-in may also comprise try-in teeth. Thus the try-in may also be denoted a try-in denture, a try-in gingival, try-in teeth etc. 
         [0168]    In some embodiments the method further comprises printing the try-in gingival in a deformable material, such as wax. 
         [0169]    In some embodiments the method further comprises scanning the try-in after testing in the patient&#39;s mouth and optional adjustment. 
         [0170]    In some embodiments the method further comprises automatically detecting the changes in the scan of the try-in after the adjustments and modifying the denture design based on this. 
         [0171]    This may be performed by overlaying the first unmodified design or scan of the try-in with the second modified scan or design of the try-in, and/or morphing the first unmodified design or scan to the second modified design or scan, segmenting the scan into the teeth and the gingival, and then move the gingival and/or the teeth in the two scans or designs relative to each other for providing a correct overlaying. Then the new denture design can be performed. 
         [0172]    In some embodiments the try-in gingival is made in a material which is subject to hardening. 
         [0173]    In some embodiments after the try-in has been tested in the patient&#39;s mouth and optionally adjusted, the method further comprises hardening the try-in gingival, and providing the try-in gingival to be at least part of the denture. 
         [0174]    In some embodiments the method further comprises hardening the try-in by means of light radiation. 
         [0175]    In some embodiments after the try-in has been tested in the patient&#39;s mouth and optionally adjusted, a gingival part is modeled based on the optionally adjusted try-in and printed in a hard material. 
         [0176]    In some embodiments the try-in comprises the manufactured modeled teeth. 
         [0177]    In some embodiments the manufactured modeled teeth used in the try-in are also inserted in the final denture. 
         [0178]    Thus only one set of manufactured artificial teeth are manufactured since the teeth are used both in the try-in and in the final denture. 
         [0179]    In some embodiments at least one of the manufactured modeled teeth used in the try-in is replaced with a new manufactured modeled tooth, when inserted in the final denture. 
         [0180]    If one or more of the manufactured artificial teeth appears not to fit in the denture after testing them in the try-in, those teeth not fitting will be replaced by manufactured remodel teeth. 
         [0181]    In some embodiments the method further comprises using a dynamic virtual articulator for simulating occlusion of the teeth set comprising the modeled denture and any teeth still present in the patient&#39;s mouth. 
         [0182]    In some embodiments the modeled denture and any teeth still present in the patient&#39;s mount comprise a virtual upper jaw and a virtual lower jaw of the teeth set. 
         [0183]    In some embodiments the method further comprises positioning a virtual alignment plane relative to the virtual upper jaw and the virtual lower jaw. 
         [0184]    In some embodiments the virtual alignment plane is fixed relative to the virtual articulator. 
         [0185]    In some embodiments the virtual alignment plane is a default occlusal plane. 
         [0186]    In some embodiments the virtual alignment plane is plane or curved. 
         [0187]    In some embodiments the method further comprises automatic movement of the virtual alignment plane relative to the movement of the virtual teeth in the denture, when the virtual teeth are being modeled. 
         [0188]    In some embodiments one or more of the steps of the method is computer-implemented. 
         [0189]    Furthermore, the present invention relates to a computer program product comprising program code means for causing a data processing system to perform the method above when said program code means are executed on the data processing system, and a computer program product comprising a computer-readable medium having stored thereon the program code means. 
         [0190]    The present invention relates to different aspects including the method described above and in the following, and corresponding methods, devices, systems, uses, and/or product means, each yielding one or more of the benefits and advantages described in connection with the first mentioned aspect, and each having one or more embodiments corresponding to the embodiments described in connection with the first mentioned aspect and/or disclosed in the appended claims. 
         [0191]    In particular, disclosed herein is a system for modeling and/or manufacturing a denture for a patient, where the denture comprises a gingival part and artificial teeth, wherein the system comprises:
       means for providing a 3D scan comprising at least part of the patient&#39;s oral cavity;   means for virtually modeling at least part of the denture using the 3D scan;   means for obtaining virtual teeth to represent the artificial teeth;   means for virtually modeling at least one of the virtual teeth to obtain a set of modeled virtual teeth;   means for manufacturing the modeled virtual teeth in a first material;   means for manufacturing the gingival part in a second material; and   means for manufacturing at least part of the denture by means of computer aided manufacturing (CAM).       
 
         [0199]    In particular, disclosed herein is a system for modeling and manufacturing a denture for a patient, where the denture comprises a gingival part and artificial teeth, wherein the system comprises:
       means for providing a 3D scan comprising at least part of the patient&#39;s oral cavity;   means for virtually modeling at least part of the denture using the 3D scan;   means for obtaining virtual teeth to represent the artificial teeth;   means for virtually modeling at least one of the virtual teeth to obtain a set of modeled virtual teeth;   means for virtually modeling attachment of the artificial teeth in the gingival part;   means for manufacturing the modeled virtual teeth in a first material;   means for manufacturing the gingival part in a second material; and   means for manufacturing at least part of the denture by means of computer aided manufacturing (CAM).       
 
         [0208]    Disclosed is also a device for modeling and/manufacturing a denture for a patient, where the denture comprises a gingival part and artificial teeth, wherein the device comprises:
       means for providing a 3D scan comprising at least part of the patient&#39;s oral cavity;   means for virtually modeling at least part of the denture using the 3D scan;   means for obtaining virtual teeth to represent the artificial teeth;   means for virtually modeling at least one of the virtual teeth to obtain a set of modeled virtual teeth;   means for manufacturing the modeled virtual teeth in a first material;   means for manufacturing the gingival part in a second material; and   means for manufacturing at least part of the denture by means of computer aided manufacturing (CAM).       
 
         [0216]    According to another aspect of the invention a fixture apparatus is disclosed for retaining a blank from which at least manufactured teeth of a denture are adapted to be manufactured according to any of the preceding claims. 
         [0217]    It is an advantage since hereby the blank is arranged in the fixture in a known position relative to the grinding/milling machinery. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0218]    The above and/or additional objects, features and advantages of the present invention, will be further elucidated by the following illustrative and non-limiting detailed description of embodiments of the present invention, with reference to the appended drawings, wherein: 
           [0219]      FIG. 1  shows an example of a flow chart of the method. 
           [0220]      FIGS. 2 a   ) to  2   c ) show examples of manufactured dentures. 
           [0221]      FIGS. 3 a   ) and  3   b ) show examples of virtual modeling of dentures. 
           [0222]      FIGS. 4 a   ) to  4   c ) show examples of different implant bars. 
           [0223]      FIGS. 5 a   ) to  5   c ) show examples of different attachment types. 
           [0224]      FIGS. 6 a   ) and  6   b ) show examples of implant bridges. 
           [0225]      FIG. 7  shows an example of combination of different CAD modeling for a set of teeth. 
           [0226]      FIGS. 8 a   ) and  8   b ) show an example of a how a denture and a partial removable framework are attached to each other. 
           [0227]      FIGS. 9 a   ) and  9   b ) show examples of modeling the gingival part. 
           [0228]      FIGS. 10 a   ) to  10   f ) show examples of attachment of the artificial teeth in the gingival part. 
           [0229]      FIG. 11  shows an example of a flow chart of an aspect of the method. 
       
    
    
     DETAILED DESCRIPTION 
       [0230]    In the following description, reference is made to the accompanying figures, which show by way of illustration how the invention may be practiced. 
         [0231]      FIG. 1  shows an example of a flow chart of the method for computer-aided modeling and computer-aided manufacturing of a denture comprising a gingival part and artificial teeth. 
         [0232]    In step  101  a 3D scan comprising at least part of the patient&#39;s oral cavity os provided. 
         [0233]    In step  102  at least part of the denture is virtually modeled using the 3D scan. 
         [0234]    In step  103  virtual teeth is obtained to represent the artificial teeth. 
         [0235]    In step  104  at least one of the virtual teeth is virtually modeled to obtain a set of modeled virtual teeth. 
         [0236]    In step  105  the modeled virtual teeth is manufactured in a first material. 
         [0237]    In step  106  the gingival part is manufactured in a second material. 
         [0238]    In step  107  at least part of the denture is manufactured by means of computer aided manufacturing (CAM). 
         [0239]      FIG. 2  shows examples of manufactured dentures. 
         [0240]      FIG. 2 a   ) shows pictures of a denture  201  which is, or is a part of, or comprises a partial denture. The partial denture  201  comprises a framework  206  and a gingival part  203  and a teeth part comprising artificial acrylic teeth  205 . 
         [0241]    In the top image, the partial denture is arranged next to a model of the patient&#39;s present teeth, and the denture is seen from below, i.e. from the side pointing towards the palate. 
         [0242]    In the bottom image, the partial denture is arranged on the model of the patient&#39;s teeth, and the denture is seen from above, i.e. from the side pointing towards the surroundings when the denture is arranged in the mouth of the patient. 
         [0243]      FIG. 2 b   ) shows pictures of an upper denture  201  and a lower denture, which are both partial dentures. The partial dentures  201  comprise a framework  206  and a gingival part  203  and the top image also shows a teeth part comprising artificial acrylic teeth  205 . 
         [0244]    In the top image, the partial dentures are arranged on the models of the patient&#39;s present teeth, and the dentures are seen from above or from the frontside. 
         [0245]    In the bottom image, the partial dentures are arranged next to the models of the patient&#39;s teeth, and the dentures are seen from below or from the backside. In the bottom image the dentures are shown without the artificial teeth or the veneering of the metal framework. 
         [0246]      FIG. 2 c   ) shows pictures of a denture  201  which is a full maxillary denture, i.e. a denture for the upper arch. The denture  201  comprises a gingival part  203  and a teeth part comprising artificial teeth  205  made of acrylics. 
         [0247]    In the top image, the partial denture is arranged on the model of the patient&#39;s present teeth, and the denture is seen from above or from the frontside. 
         [0248]    In the bottom image, the partial denture is arranged next to the model of the patient&#39;s teeth, and the denture is seen from below or from the backside. 
         [0249]    The denture  201  shown in  FIG. 2 c   ) is a removable denture, and it is not attached to the mouth by any attachment means when in use, so the patient can at any time remove the denture. The denture  201  of  FIG. 2 c   ) is held in place in the patient&#39;s mouth by means of friction, suction, negative pressure etc. 
         [0250]    The dentures  201  of  FIG. 2 a   ) and  FIG. 2 b   ) may be removable for the patient, however alternatively the dentures may be attached to the existing teeth by some attachment means, which only the dentist should manage. 
         [0251]    InteraDent Zahntechnik GmbH in Lübeck, Germany has provided the images of the different dentures shown in  FIG. 2 . 
         [0252]      FIG. 3  shows examples of virtual modeling of dentures. 
         [0253]      FIG. 3 a   ) shows an example of virtual modeling of an implant bar for implants and denture. 
         [0254]    The virtual denture  301  comprises a virtual teeth part  304  comprising virtual teeth  305 , and a virtual gingival part  303 . Inside the virtual denture  301  which is transparent, a virtual implant bar  307  is seen and marked with dots above it. A number of virtual implant screws  308  are also seen sticking out underneath the denture  301 . The implant screws  308  are attached to the implant bar  307 . A part of a scan  302  of the patient&#39;s jaw is also seen inside the denture  301 . 
         [0255]    The implant bar  307  is modeled for optimal fit to the denture  301  and implants  308  using virtual tools in the computer aided drawing (CAD) software. Virtual measurements can be performed to validate space and distances of the denture  301 , the scan  302 , the implant bar  307 , the implants screws  308  etc. The connection from the implant bar  307  to the implants  308  can be shaped as a cylindrical extension, as a freeform emergence profile etc. 
         [0256]      FIG. 3 b   ) shows an example of virtual modeling of a removable denture. 
         [0257]    A virtually modeled tooth  305  in a partial removable framework is arranged with a distance to the existing gingival  316 , and the space  319  between the tooth and the existing gingival is virtually blocked out for avoiding having the denture material between the teeth and the existing gingival when the manufactured denture is worn by the patient. The gingival part  303  is modeled such that the tooth  305  is attached in the gingival part  303 . 
         [0258]      FIG. 4  shows examples of different implant bars. 
         [0259]      FIG. 4 a   ) shows an example of an implant bar  407  for a full denture (not shown). The denture may be a removable denture, i.e. it may be removably attached to the implant bar  407  by means of attachments in the form of e.g. clips (not shown) which can be snapped on and off the implant bar  407 . The implant bar  407  comprises holes  411  for receiving implants. 
         [0260]      FIG. 4 b   ) shows an example of an implant bar  407  for a full denture (not shown). The denture may be a removable denture, i.e. it may be removably attached to the implant bar  407  by means of attachments  409  in the form of locators present on both the denture and on the implant bar  407 , where the locators  409  provides that the denture can be clicked on and off the implant bar  407 . 
         [0261]    The implant bar  407  comprises holes  411  for receiving implants. 
         [0262]      FIG. 4 c   ) shows an example of an implant bar  407  for a full denture (not shown). The denture may be a fixed denture, i.e. it may be fixedly attached to the implant bar  407  e.g. by gluing part of the denture into the retention holes  410  in the implant bar  407 . This may be performed by using acrylics in the denture, and the soft acrylics from the denture will then run into the retention holes  410  of the implant bar  407  and thereby attaching the denture to the implant bar  407 . 
         [0263]    The implant bar  407  comprises holes  411  for receiving implants. 
         [0264]      FIG. 5  shows examples of different attachment types. 
         [0265]      FIG. 5 a   ) shows an attachment in the form of a locator  509 . The locator  509  may comprise a male part on e.g. the implant bar and a female part on e.g. the denture or vice versa, and the male part and the female part may work as a button. 
         [0266]      FIG. 5 b   ) shows an attachment in the form of a ball attachment  509 . 
         [0267]      FIG. 5 c   ) shows an attachment in the form of retention holes  510 . 
         [0268]    Another type of attachment may be a slide attachment, however any kind of attachment from a CAD library may be used. 
         [0269]    When modeling the denture and implant, the different kinds of attachments can be added anywhere on the implant bar, and the attachments can then be rotated and translated for fine-adjustment of their position and angles. 
         [0270]      FIG. 6  shows examples of implant bridges. 
         [0271]      FIG. 6 a   ) shows an example of an implant bridge  607  onto which a full denture is adapted to be arranged. On the side opposite to where the denture should be attached, the implant bridge  607  comprises protrusions  612  from holes for receiving implants (not shown). 
         [0272]      FIG. 6 b   ) shows an example of an implant bridge  607  comprising pins  613  where each pin is adapted to receive an artificial tooth having a hole in it for fitting over the pin, or where the pin is adapted to be covered by veneering in the form of e.g. ceramics or composite material for resembling teeth. Thus in this case the denture may be defined as comprising the artificial teeth attached onto the pins, or the denture may be defined as the veneering resembling teeth. On the side opposite to the pins  613 , the implant bridge  607  comprises protrusions  612  from holes for receiving implants (not shown). 
         [0273]    An original wax-up bar design may be scanned for remodeling the implant bar in a new material to create a digitized file that is suitable for e.g. copy milling. Adjustments to the digitized model can be applied to achieve the optimal copy milling result. 
         [0274]      FIG. 7  shows an example of combination of different CAD modeling for a set of teeth. 
         [0275]    All restorations may be designed in the same modeling session using embodiments of the present method. When all restorations are modeled in the same session the efficiency and clinical result will be improved. 
         [0276]      FIG. 7  shows a standard bridge  714 , full anatomical crowns  715 , an implant bridge  707  and implants  708 . A denture should also be modeled using CAD and after manufacturing be attached to the implant bridge  707  and e.g. on the standard bridge  714 . Alternatively, veneering can be applied to the standard bridge to make it an anatomical bridge, e.g. veneering in the form of porcelain. 
         [0277]      FIG. 8  shows an example of a how a denture and a partial removable framework are attached to each other. 
         [0278]      FIG. 8 a   ) shows a partial removable framework  806  with retention grid and holes  817  but without artificial teeth or gingival attached. 
         [0279]      FIG. 8 b   ) shows a cross section of a denture with a partial removable framework, for example as those seen in  FIGS. 2 a   ) and  2   b ). The partial removable framework  806  is embedded in the gingival part  803 , since the gingival part  803  is both present above and below the framework  806 . An artificial tooth  805  is arranged in the gingival part, and the gingival part  803  rests on the patient&#39;s real physiological gingival  816 . 
         [0280]    If the gingival part  803  is poured in silicone, then the liquid silicone can flow into the holes of the retention grid  817  in the framework  806 . But if the gingival part  803  is printed, then there is no liquid silicone to flow into the holes of the retention grid  817 . For the framework  806  and the gingival part  803  to be attached to each other, the gingival part  803  may then be separated as indicated by the separation line  818  into two or more pieces which can then be assembled around the framework  806 . The separation line(s)  818  can be at other places in the gingival part  803 , e.g. vertical instead of horizontal etc. Alternatively and/or additionally, the framework  806  including the retention grid  817  can be separated into two or more pieces. 
         [0281]      FIG. 9  shows examples of modeling the gingival part. 
         [0282]      FIG. 9 a   ) shows points  920  marked on the teeth  905  for indicating that the gingival part  903  should end there. A first offset  921 , marked by arrows, of the gingival part  903  from the existing gingival  916  may be determined, an second offset, marked by arrows,  922  of the gingival part  903  from the teeth  905  may be determined, a smooth transition  923  connecting the first offset  921  from the existing gingival  916  and the second offset  922  from the teeth may be performed using a lofting operation. 
         [0283]      FIG. 9 b   ) shows an example of offsetting  922 , marked by arrows, the gingival part  903  around the virtual teeth  905 . By offsetting the gingival part  903  around the virtual teeth  903  and finally around the manufactured teeth, the gingival part  903  will look more natural since this is how the physiological gingival looks. 
         [0284]      FIG. 10  shows examples of attachment of the artificial teeth in the gingival part. 
         [0285]      FIG. 10 a   ) shows an example where holes  1024  are modeled and manufactured in the gingival part  1003  to receive the manufactured teeth. In the  FIG. 14  holes  1024  are provided, and thus this denture is configured for receiving  14  artificial teeth, which may be all the teeth of the lower or upper jaw of a patient. Thus this is a full denture for the upper or lower jaw. Fewer holes  1024  may be manufactured in the gingival part  1003 , if the denture is not a full denture, but a partial denture. 
         [0286]      FIG. 10 b   ) shows an example where the hole  1024  in the gingival part comprises undercuts  1025 , whereby the artificial tooth  1006  can be attached in the hole  1024  by press-fitting. 
         [0287]      FIG. 10 c   ) shows an example where the artificial tooth  1005  is attached in the hole  1024  of the gingival part by means of a fastening means in the form of a screw  1026  in the bottom of the hole  1024 . A screw hole  1027  is manufactured in the bottom of the hole  1024 , and a screw hole  1028  is manufactured in the bottom of the artificial tooth  1005 . 
         [0288]      FIG. 10 d   ) shows an example where the artificial tooth  1005  is attached in the hole  1024  in the gingival part by means of ball-shaped interlocking features  1029 ,  1030 . The part of the interlocking feature in the hole  1024  may be denoted the hole interlocking feature  1029 , and the part of the interlocking feature in the artificial tooth  1005  may be denoted the tooth interlocking feature  1030 . The hole interlocking feature  1029  and the tooth interlocking feature  1030  match each other such that the tooth  1005  is fixed in the hole  1024  in the gingival part by means of the interlocking features  1029  and  1030 . 
         [0289]    There may be one or more, such as one, two, three, four or five sets of interlocking features for each artificial tooth. 
         [0290]    The tooth interlocking feature  1030  may be configured to be pushed in to align with the plane surface of the tooth where it is arranged, for example when pressure is applied to the interlocking feature  1030 , e.g. when a machine or a dental technician presses the interlocking feature  1030  in for pushing the artificial tooth  1005  in the hole  1024  in the gingival. When the artificial tooth  1005  has been pushed down into the hole  1024 , the tooth interlocking feature  1030  is configured to push out again and file the space in the side wall of the hole  1024  provided by the corresponding hole interlocking feature  1029 . 
         [0291]      FIG. 10 e   ) shows an example where the artificial tooth  1005  is attached in the hole  1024  in the gingival part by means of ball-shaped interlocking features  1029 ,  1030 . The part of the interlocking feature in the hole  1024  may be denoted the hole interlocking feature  1029 , and the part of the interlocking feature in the artificial tooth  1005  may be denoted the tooth interlocking feature  1030 . The hole interlocking feature  1029  and the tooth interlocking feature  1030  match each other such that the tooth  1005  is fixed in the hole  1024  in the gingival part by means of the interlocking features  1029  and  1030 . 
         [0292]    There may be one or more, such as one, two, three, four or five sets of interlocking features for each artificial tooth. 
         [0293]    The hole interlocking feature  1029  may be configured to be pushed in to align with the plane surface of the wall of the hole  1024  where it is arranged, for example when pressure is applied to the interlocking feature  1029 , e.g. when a machine or a dental technician pushes the artificial tooth  1005  into the hole  1024  in the gingival. When the artificial tooth  1005  has been pushed down into the hole  1024 , the hole interlocking feature  1029  is configured to push out again and file the space in the side wall of the tooth  1005  provided by the corresponding tooth interlocking feature  1030 . 
         [0294]      FIG. 10 f   ) shows an example where the artificial tooth  1005  is attached in the gingival part by means of providing a bore  1031  in the area of the artificial teeth which is adapted to be arranged in the hole  1024  in the gingival part, and arranging a bar  1032  in the bore  1031 , where the bar  1032  is adapted to extend outside the hole  1024  of the gingival part  1003  for retaining the artificial tooth  1005  in the gingival part  1003 . The hole  1024  in the gingival part  1003  may comprises holes  1033  in the side walls of the hole  1024  such that the bar  1032  can fit in the hole  1024 . 
         [0295]    Alternatively and/or additionally the artificial teeth may be attached, e.g. in holes, in the gingival part by means of glue, cement, tape, vacuum or negative pressure created by means of moisture in the patient&#39;s mouth etc. 
         [0296]      FIG. 11  shows an example of a flow chart of the method for computer-aided modeling and computer-aided manufacturing of a denture comprising a gingival part and artificial teeth. 
         [0297]    In step  101  a 3D scan comprising at least part of the patient&#39;s oral cavity os provided. 
         [0298]    In step  102  at least part of the denture is virtually modeled using the 3D scan. 
         [0299]    In step  103  virtual teeth is obtained to represent the artificial teeth. 
         [0300]    In step  104  at least one of the virtual teeth is virtually modeled to obtain a set of modeled virtual teeth. 
         [0301]    In step  105  attachment of the artificial teeth in the gingival part is virtually modeling for securing an fixing the artificial teeth in the gingival part. 
         [0302]    In step  106  the modeled virtual teeth is manufactured in a first material. 
         [0303]    In step  107  the gingival part is manufactured in a second material. 
         [0304]    At least part of the denture is manufactured by means of computer aided manufacturing (CAM). 
         [0305]    Although some embodiments have been described and shown in detail, the invention is not restricted to them, but may also be embodied in other ways within the scope of the subject matter defined in the following claims. In particular, it is to be understood that other embodiments may be utilised and structural and functional modifications may be made without departing from the scope of the present invention. 
         [0306]    In device claims enumerating several means, several of these means can be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims or described in different embodiments does not indicate that a combination of these measures cannot be used to advantage. 
         [0307]    It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. 
         [0308]    The features of the method described above and in the following may be implemented in software and carried out on a data processing system or other processing means caused by the execution of computer-executable instructions. The instructions may be program code means loaded in a memory, such as a RAM, from a storage medium or from another computer via a computer network. Alternatively, the described features may be implemented by hardwired circuitry instead of software or in combination with software.