Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C13/00—Dental prostheses; Making same
  • A61C13/10—Fastening of artificial teeth to denture palates or the like
  • A61C13/1003—Fastening of artificial teeth to denture palates or the like by embedding in base material
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C13/00—Dental prostheses; Making same
  • A61C13/0003—Making bridge-work, inlays, implants or the like
  • A61C13/0004—Computer-assisted sizing or machining of dental prostheses
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C13/00—Dental prostheses; Making same
  • A61C13/08—Artificial teeth; Making same
  • A61C13/082—Cosmetic aspects, e.g. inlays; Determination of the colour
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C13/00—Dental prostheses; Making same
  • A61C13/08—Artificial teeth; Making same
  • A61C13/087—Artificial resin teeth
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C13/00—Dental prostheses; Making same
  • A61C13/10—Fastening of artificial teeth to denture palates or the like
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C9/00—Impression cups, i.e. impression trays; Impression methods
  • A61C9/004—Means or methods for taking digitized impressions
  • A61C9/0046—Data acquisition means or methods
  • A61C9/0053—Optical means or methods, e.g. scanning the teeth by a laser or light beam
• • G—PHYSICS
  • G16—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
  • G16H—HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
  • G16H20/00—ICT specially adapted for therapies or health-improving plans, e.g. for handling prescriptions, for steering therapy or for monitoring patient compliance
  • G16H20/40—ICT specially adapted for therapies or health-improving plans, e.g. for handling prescriptions, for steering therapy or for monitoring patient compliance relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture

Definitions

• This invention generally relates to a system and a method for virtually reducing and milling at least one artificial tooth adapted to be inserted in a denture for a patient.
• the process of fabricating a denture usually begins with a dental impression of the maxilla or mandible. This impression is used to create a stone model that represents the arch. A wax rim is fabricated to assist the dentist or denturist with establishing the vertical dimension of occlusion. After this a bite registration is created to marry the position of one arch to the other. Once the relative position of each arch to the other is known, the wax rim can be used as a base to place the selected denture teeth in correct position. This arrangement of teeth is tried in to the mouth so that adjustments can be made to the occlusion. After the occlusion has been verified by the doctor with the patient, and all phonetic requirements are met, the denture is processed.
• Processing a denture is usually performed in a lost- wax process whereby the form of the final denture, including the selected pre-manufactured acrylic denture teeth, is invested in stone. This investment is then heated, and the wax corresponding to the gingival part of the denture is removed through a sprue when it melts. The remaining cavity around the pre-manufactured acrylic denture teeth is then either filled by forced injection or pouring of the un cured denture acrylic providing the gingival part of the denture. After a curing period, the stone investment is removed, the acrylic of the gingival part of the denture is polished, and the denture is complete.
• 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.
• 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.
• US2006040236 discloses a method of creating a dental restoration customized to the clinical needs of a patient comprising the steps of: preparing a patient'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'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's existing dental structures.
• pre-manufactured artificial teeth In particular there is a need to more effectively modify pre-manufactured artificial teeth.
• the advantage of using pre-manufactured artificial teeth is that these are typically cheap and very realistic, whereas milling full custom denture teeth will increase the cost and time as considerable work will have to be done to make them look satisfactory.
• Disclosed is a method of virtually designing a reduced shape of at least one artificial tooth adapted to be inserted in a denture for a patient, where the artificial tooth is configured to be provided as a physical artificial tooth and as a corresponding virtual artificial tooth, where the artificial tooth is configured to have an original shape, and where the denture is configured to comprise physical artificial teeth and an artificial gingival, wherein the method comprises:
• the physical artificial tooth is configured to be placed in a milling fixture, such that the arrangement of the physical artificial tooth relative to the milling fixture is known, whereby the determined part of the physical artificial tooth is configured to be cut away by milling in the milling machine, thereby obtaining a reduced physical artificial tooth.
• a method of virtually reducing and milling at least one artificial tooth adapted to be inserted in a denture for a patient where the artificial tooth is provided as a physical artificial tooth and as a corresponding virtual artificial tooth, where the artificial tooth has an original shape, and where the denture is configured to comprise physical artificial teeth and an artificial gingival, wherein the method comprises:
• the dental technician needs to grind off some of the length of each of the artificial teeth by handicraft.
• the dental technician grind some material off each of the artificial teeth and then try to insert the artificial teeth in the artificial gingival again to see if they fit in now. If some of the artificial teeth still do not fit in the gingival, e.g. they are still too long, then the dental technician need to grind of some more material from the artificial teeth, and then try to insert them again. This can take a long time, as all the artificial teeth probably must be grinded down.
• the artificial teeth may not be too short, because then there will not be enough retention between each artificial tooth and the artificial gingival, as the artificial teeth must be glued to the artificial gingival to fix them in the denture, and if the artificial teeth are not retained good enough, they may fall out of the denture, they may reduce the functionality of the denture, if the patient cannot chew properly with the artificial teeth in the denture etc.
• the artificial teeth should not be too long or too short, they must have a sufficient length to provide optimal retention in the artificial gingival, and if grinding the artificial teeth by handicraft, the process of fabricating can be very long and time- consuming for the dental technician, and the result may not be optimal.
• it can be ensured that each artificial tooth is cut the optimal length for optimal retention in the artificial gingival of the denture.
• the arrangement or position of the physical artificial tooth relative to the milling fixture is known, such as well-defined, given, or predetermined, because then the milling tool or milling cutter in the milling machine can cut off exactly the determined part of the tooth to obtain the reduced artificial tooth.
• the milling machine can be programmed to cut the exact amount of material off the artificial tooth and cut it off in the determined shape to obtain the planned reduced shape of the artificial tooth, because the movement of the milling tool can be programmed to move in an exact way to obtain the reduced shape of the artificial tooth, which was virtually designed.
• the milling machine is programmed or loaded with information, such as with a digital file, of the part of the artificial tooth to be cut off, and this information comes from the virtual design made in a software program.
• the cut through the artificial tooth to obtain the reduced shape is determined.
• the milling machine has information of where the artificial tooth is arranged in its fixture in an x, y, z coordinate system of the milling machine, so the drill of the milling machine can automatically move to the position(s) where the determined cut shall be.
• the software may output the parts of the shape of the reduced artificial tooth, e.g. the surface of the artificial tooth, which does not correspond to the original shape of the artificial tooth in order for the milling machine to make the desired reduced artificial tooth.
• the virtually designed reduced shape of the artificial tooth may be present or saved in a known coordinate system.
• This coordinate system may be transferred into the coordinate system of the milling machine, such that the milling tool in the milling machine can be programmed or controlled to perform the milling on the determined parts of the pre-manufactured artificial tooth.
• the milling fixture is a fixture for holding the artificial tooth, where the fixture is adapted to be placed in the milling machine for milling the artificial tooth. It is an advantage that the artificial tooth is arranged in the fixture such that exactly the correct amount of material is milled off the artificial teeth.
• the milling may be digitally automated via computer numerical control (CNC).
• CNC computer numerical control
• Milling can be of the gingival surface or part of the artificial tooth and/or of the incisal/occlusal surface or part of the artificial tooth.
• the gingival surface of the artificial tooth and the incisal/occlusal surface of the artificial tooth can be milled in turns, when the artificial tooth is arranged in the fixture in the milling machine.
• the fixture can be turned 180 degrees in the milling machine, so that the other surface of the tooth can be milled.
• the milling fixture can be a 98 mm blank, which is a standard blank configured to be inserted in a milling machine.
• the standard 98 mm blank may comprise cavities for insertion of the pre-manufactured artificial teeth.
• the cavities of the milling fixture blank may match or be configured to accommodate standard sets of artificial teeth for a denture.
• the blank itself may be a standard blank.
• the cavities in the blank may be custom or specific for a specific set of artificial teeth. Thus if ten different sets of artificial teeth exist, then ten different milling fixture blanks can be made.
• a milling fixture blank comprising pre-manufactured artificial teeth
• a milling fixture blank comprising pre-manufactured artificial teeth
• only certain parts of surfaces of the artificial teeth shall be milled, i.e. the parts or surfaces of the artificial teeth which should be reduced according to the reduced design of the artificial teeth.
• the milling fixture blank itself shall not be milled, as it shall typically be reused for another patient's set of pre-manufactured artificial teeth to be milled.
• the artificial tooth is a pre-manufactured tooth, and it is an advantage that material can milled off the artificial tooth, because typically material should be removed from the artificial tooth before insertion in the artificial gingival of the denture, because the artificial teeth are too big.
• the artificial tooth may typically be pre-manufactured to have a size so big that it will fit to any patient and any denture, and the tooth may therefore be too big for almost any case, and the artificial tooth will therefore in most cases need to be reduced in size to fit into the denture.
• the physical artificial tooth is configured to have an original shape so big that material can be cut off by milling.
• the reduced shape of the artificial tooth will always be smaller than the original shape since material is removed from it in the milling process.
• the dental designer designs the shape of the artificial tooth it will be a reduced shape, since in a milling machine material can only be removed from the pre-manufactured teeth, not added, so the designed artificial teeth will be reduced relative to the original artificial teeth.
• the artificial teeth may for example be Vita FT teeth with shade 2M2.
• the reduced shape of the artificial tooth may correspond to designing or determining a distance between the gingival surface of the at least one artificial tooth and the gum surface of the artificial gingival.
• the gingival surface of the artificial tooth is the surface, part or side pointing towards the artificial gingival and the patient's gum.
• the gum surface of the artificial gingival is the surface, part or side pointing towards the patient's natural gum, when the denture is placed in the patient's mouth.
• the difference between the original shape and the reduced shape of the artificial tooth may correspond in 2-dimensions to the difference between a predetermined length of the artificial tooth and a virtually determined distance between the gingival surface of the artificial tooth and the gum surface of the artificial gingival.
• the different steps of method may be performed by a dental technician in for example a dental lab, or in different physical locations, such as in a dental clinic, in a dental laboratory, in a milling center, in different laboratories, in different rooms in a laboratory etc.
• the different steps of the method may be performed by different persons, such as a dentist, a dental assistant, a dental technician, a milling operator etc.
• a dentist may perform a 3D scanning of the patient's oral cavity, thereby capturing any teeth in the mouth, the gums etc.
• the 3D scanning can be provided as a 3D representation of the oral cavity.
• the 3D representation can be provided to a dental technician, i.e. the 3D representation may be obtained by the dental technician.
• the dental technician may then perform the virtual designing and determination of the reduced shape of the artificial tooth.
• the physical artificial tooth is now configured to be arranged in the milling fixture and the milling in the milling machine can be performed based on the virtual design of the reduced shape of the artificial tooth.
• the milling machine may be arranged in the same location as the dental technician or in a different location, and the milling machine may be operated by the dental technician or by a milling machine operator.
• the steps of the method are worded to comprises steps to be performed in a CAD software program configured to be operated by a dental technician.
• the artificial tooth cited above is one of the artificial teeth adapted to be inserted in the artificial gingival.
• a number of artificial teeth may be inserted in an artificial gingival of a denture.
• Each artificial tooth may be reduced, adjusted, or adapted as described above before being inserted in the denture.
• artificial teeth When the term “artificial teeth” is used without the term “physical” or “virtual” before it, this may mean that the artificial teeth are both the physical artificial teeth and the virtual artificial teeth, or that it is the concept artificial teeth that is meant, whereby neither physical nor virtual is suitable to add before, or that it is clear from the context, whether it is the physical or the virtual artificial teeth that is meant.
• the physical artificial teeth are pre-manufactured, acrylic teeth.
• the method comprises developing a milling strategy based on the virtually determined part of the artificial tooth to be cut away by milling in a milling machine.
• a milling strategy for the milling tool in the milling machine can be developed.
• the milling strategy can be determined by CAD/CAM software, which combines the information of the virtually designed teeth from the CAD software with information of the control, settings, possible movement patterns etc. of the milling tool and milling machine axes etc..
• the milling strategy may comprise determining at which surfaces of the pre- manufactured artificial teeth the milling tool should mill, how many times the milling tool should mill along the different surfaces, in which order the different surfaces should be milled etc. For example the milling tool should first mill along a surface defined from point (x1 , y1 , z1 ) to point (x2, y2, z2), then the milling tool should mill along a surface defined from point (x3, y3, z3) to point (x4, y4, z4) etc. Then when the pre-manufactured artificial teeth are arranged in the milling machine, the milling tool will only mill along the predetermined surfaces.
• the reduced shape of the artificial tooth is at the gingival surface of the artificial tooth, whereby the part of the artificial tooth to be cut away by milling is on the gingival surface of the artificial tooth.
• the reduced shape of the artificial tooth is at the incisal/occlusal surface of the artificial tooth, whereby the part of the artificial tooth to be cut away by milling is on the incisal/occlusal surface of the artificial tooth.
• the artificial teeth may also be too long in the incisal/occlusal direction, so this surface of the artificial teeth may also be cut off by milling.
• the occlusal/incisal surface of the artificial tooth may look too perfect and thus needs to be milled or grinded a bit to look more natural, e.g. relative to the patient's age.
• the teeth typically get more worn over the years, due to chewing food etc, and therefore the teeth will normally not have a perfect "original" shape in an adult person.
• the milling of the incisal/occlusal surface of the artificial teeth may be performed before or after milling the gingival surface of the artificial teeth.
• the method comprises providing a digital library comprising the virtual artificial tooth corresponding to the physical artificial tooth.
• Designing the part of the artificial tooth to be cut off In some embodiments the part of the artificial tooth to be cut away by milling is virtually determined by an offset. In some embodiments the part of the artificial tooth to be cut away by milling on the gingival surface of the artificial tooth is virtually determined by offsetting the gum surface of the artificial gingival.
• the offset is different from zero providing that the gingival surface of the artificial tooth is present with a distance to the gum surface of the artificial gingival. In some embodiments the offset is zero providing that the gingival surface of the artificial tooth is present on the gum surface of the artificial gingival.
• the offset may be zero corresponding to no offset, whereby the artificial tooth is flush or level with the gum surface of the artificial gingival.
• the part of the artificial tooth to be cut away by milling on the gingival surface of the artificial tooth is at least partly determined by the material properties of the artificial gingival and/or physical artificial tooth.
• the offset between the gingival surface of artificial tooth and the gum surface of the artificial gingival may typically be about 0.5 mm - 1 mm, which may be suitable for retaining the artificial tooth and for suitable functionality of the denture and for an aesthetic appearance.
• the artificial gingival is virtually designed and manufactured comprising a hole for each of the artificial teeth, where the shape of a hole corresponds to the shape of the gingival surface of the respective reduced artificial tooth.
• each of the reduced artificial teeth are adapted to be fixed in the artificial gingival. The fixation may be e.g. by means of glue or similar attachment means.
• Milling fixture In some embodiments the milling fixture is a standard fixture adapted for receiving different kinds/types of artificial teeth.
• the milling fixture is specific for the artificial tooth.
• the shape of the milling fixture corresponds to the shape of the specific artificial tooth, such that when the artificial tooth is inserted in the milling fixture, the artificial tooth is fixed, such as not being able to move, whereby the position of the artificial tooth is fixed and well-known, whereby the milling cutter can cut the artificial tooth exactly corresponding to the virtual design due to the information of the position of the artificial tooth.
• the artificial tooth is adapted to be arranged in a cavity in the milling fixture.
• the milling fixture may comprise or be a cavity, where the cavity may correspond to the shape of the artificial tooth such that the artificial tooth is steadily arranged in the fixture.
• the artificial tooth is adapted to be retained in the milling fixture by means of retention means.
• the milling fixture may for example comprise two parts, which can be separated when the artificial tooth shall be inserted, and after the artificial tooth has been inserted in the fixture, the fixture should be locked again such that the artificial tooth is held tightly in place.
• the locking of the fixture can be by a retention means extending through both parts of the fixture.
• the retention means is a screw in the milling fixture.
• the milling fixture is adapted to be turned in the milling machine, whereby the gingival surface and the incisal/occlusal surface of the artificial tooth are adapted to be milled in turns.
• the milling fixture is a single-tooth fixture.
• the single-tooth fixture is specific for each artificial tooth, such that the shape of the cavity of the specific single-tooth fixture corresponds to at least part of the shape of the specific artificial tooth.
• the top or crown of the artificial tooth can be placed in the fixture, so the cavity in the fixture corresponds to the shape of the top or crown of the artificial tooth.
• the base part or root part of the artificial tooth can be placed in the fixture, so the cavity in the fixture corresponds to the shape of the base or root part of the artificial tooth.
• the denture is not a full denture, but a partial denture, i.e. there is not an artificial tooth in all teeth positions in the denture, which may be the case when the patient also has one or more real teeth left, one or more implants, one or more crowns, one or more bridges etc.
• the single-tooth fixture may be reusable so that it can be used again and again.
• the single-tooth fixture may be adapted for insertion in a milling machine, such as a 31 ⁇ 2 axis milling machine.
• the fixture is a multiple-teeth fixture.
• the fixture can retain a number of artificial teeth at one time, such as all teeth for the upper or lower jaw.
• the multiple-teeth fixture is specific for a set of artificial teeth, such that the shape of each cavity of the multiple-teeth fixture corresponds to at least part of the shape of each of the artificial teeth in the set of artificial teeth.
• the multiple-teeth fixture comprises a dedicated cavity or hole for each artificial tooth from a set of artificial teeth.
• the multiple-teeth fixture may be reusable, and there may exist a multiple- teeth fixture for each set of the existing artificial teeth.
• a set of artificial teeth may be a set of oval teeth, round teeth, square teeth, long teeth, short teeth etc, for example a set of Vita MTF teeth.
• the denture is a full denture, i.e. if there should be an artificial tooth in all or many, such as the majority, of the teeth positions in the denture, because in a multiple-teeth fixture there may be a cavity or hole for all artificial teeth of an artificial teeth set.
• the multiple-teeth fixture may be 98 mm blank fixture adapted for insertion in a milling machine, such as a 31 ⁇ 2 axis milling machine.
• the milling fixture is a wax fixture which is adapted to encompass at least part of an artificial tooth.
• the artificial teeth may be molded in wax.
• the wax can be present on the middle of the artificial teeth, such that both ends of an artificial tooth are free and available for milling.
• the wax can be attached to a plate which can be inserted in the milling machine for milling the artificial teeth.
• the wax fixture may be arranged in the plate, such as a 98 mm blank, in a way so that both ends of the artificial tooth can be milled by the milling machine, e.g. by turning the wax fixture and/or blank 180 degrees.
• the wax fixture is disposable.
• the disposable wax fixture is configured to be milled together with the artificial tooth.
• the arrangement of the wax fixture and the artificial tooth may provide that both the wax fixture and the artificial tooth are milled.
• the milling blank comprises at least a teeth surface of an artificial gingiva, wherein said teeth surface is adapted to receive one or more artificial teeth.
• the milling blank from which the denture is produced as a mount for teeth where the incisal/occlusal surfaces have to be reduced it is possible to both provide an exact location and positioning of the teeth in the milling machine and also attach the teeth to the denture in the same step.
• the 3D representation of the patient's oral cavity is an intra oral scan of at least part of the patient's set of teeth and/or gums, a scan of at least part of an impression of the patient's set of teeth and/or gums, and/or a scan of at least part of a positive physical model of the patient's set of teeth and/or gums.
• the 3D scan is performed by means of laser light scanning, white light scanning, probe-scanning, X-ray scanning, and/or CT scanning.
• the virtual teeth representing artificial teeth and/or the gingival may be modeled using a 3D scan comprising at least part of the patient'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's requests and wishes.
• the virtual teeth may correspond to real, physical, pre-manufactured, artificial teeth.
• the artificial teeth may be selected by the patient at the dentist'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.
• the artificial teeth can be selected such that they resemble the patient's original teeth, and thereby look natural.
• 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.
• a 3D scan comprising the patient's oral cavity the quality of the denture may also be improved.
• the 3D scan comprising at least part of the patient's oral cavity comprises any teeth still present in the mouth, and it may be a 3D scan of an impression of the patient's teeth, it may be a 3D scan of a physical model of the patient's teeth, and/or it may be a 3D scan made directly in the mouth of the patient, i.e. an intra oral scan.
• Providing or obtaining 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.
• the modeling and manufacturing may be performed at the same physical location, or modeling and manufacturing may be performed at different physical locations.
• the order in which the different steps are performed can be different than the order above.
• the designing or modeling steps should be performed before the milling or manufacturing steps.
• the artificial teeth may be denoted a teeth part of the denture.
• a virtual gingival part may be defined to represent the gingival part of the denture.
• the virtual designing or modeling of the denture in general, and the virtual designing or modeling of the virtual teeth and the gingival part in particular, may be performed by means of computer aided designing (CAD).
• CAD computer aided designing
• - denture comprises one or more implants
• - 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.
• 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.
• 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.
• the virtual modeling of the attachment of the artificial teeth in the gingival part comprises a cavity operation.
• the cavity operation comprises subtracting the shape of the artificial teeth which is configured for being arranged in the gingival from the gingival part.
• 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.
• 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.
• 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.
• a cement gap may be virtually designed, such that there is space for glue between the artificial tooth and the hole in the artificial gingival, thus each artificial tooth may be designed to be slightly smaller than the respective hole in the artificial gingival.
• 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.
• 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.
• 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.
• the method further comprises modeling and manufacturing holes in the artificial gingival part to receive the manufactured teeth.
• the artificial teeth are manufactured in a synthetic polymer material, such as acrylic.
• Acrylic means a material consisting of or comprising or derived from acrylic.
• the method further comprises selecting the artificial teeth from a library of template teeth.
• the library may be the user's or operator's own library, a library from certain manufacturers of artificial teeth etc.
• the artificial teeth are from a user's own design of teeth for a denture, from an existing restoration etc.
• the method further comprises selecting the artificial teeth based on shape and/or color.
• the artificial teeth is provided as virtual teeth and as pre-manufactured teeth, where the virtual teeth correspond to the pre- manufactured teeth.
• 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.
• the result of the virtual modeling of the artificial teeth will be manufactured by physically modeling the pre-manufactured teeth. This may be performed using a CAD-CAM milling or grinding machine.
• at least the pre-manufactured teeth are made of a material which is adapted to be grinded and/or milled.
• the method further comprises automatic grinding or milling the pre-manufactured teeth according to the virtually designed artificial teeth by means of a CAM machine.
• pre-manufactured artificial teeth such as the acrylic library teeth described above, provides a very cost effective setup which also provides the denture with very good ethetics.
• 3D modeling is the process of developing a mathematical, wireframe representation of any three-dimensional object, called a 3D model, via specialized software. Models may be created automatically, e.g. 3D models may be created using multiple approaches: use of NURBS curves to generate accurate and smooth surface patches, polygonal mesh modeling which is a manipulation of faceted geometry, or polygonal mesh subdivision which is advanced tessellation of polygons, resulting in smooth surfaces similar to NURBS models. Intra oral scanning
• An intra-oral scanner may be configured for utilizing focus scanning, where the digital 3D representation of the scanned teeth is reconstructed from in- focus images acquired at different focus depths.
• the focus scanning technique can be performed by generating a probe light and transmitting this probe light towards the set of teeth such that at least a part of the set of teeth is illuminated.
• Light returning from the set of teeth is transmitted towards a camera and imaged onto an image sensor in the camera by means of an optical system, where the image sensor/camera comprises an array of sensor elements.
• the position of the focus plane on/relative to the set of teeth is varied by means of focusing optics while images are obtained from/by means of said array of sensor elements. Based on the images, the in -focus position(s) of each of a plurality of the sensor elements or each of a plurality of groups of the sensor elements may be determined for a sequence of focus plane positions.
• the in -focus position can e.g. be calculated by determining the light oscillation amplitude for each of a plurality of the sensor elements or each of a plurality of groups of the sensor elements for a range of focus planes. From the in -focus positions, the digital 3D representation of the set of teeth can be derived.
• 3D modeling is the process of developing a mathematical representation of the three- dimensional surface of the object via specialized software.
• the product is called a 3D model.
• a 3D model represents the 3D object using a collection of points in 3D space, connected by various geometric entities such as triangles, lines, curved surfaces, etc.
• the purpose of a 3D scanner is usually to create a point cloud of geometric samples on the surface of the object.
• 3D scanners collect distance information about surfaces within its field of view.
• the "picture” produced by a 3D scanner describes the distance to a surface at each point in the picture.
• a single a scan or sub-scan will not produce a complete model of the object.
• Multiple sub-scans such as 5, 10, 12, 15, 20, 30, 40, 50, 60, 70, 80, 90 or in some cases even hundreds, from many different directions may be required to obtain information about all sides of the object.
• These sub-scans are brought in a common reference system, a process that may be called alignment or registration, and then merged to create a complete model.
• a trianguiation 3D laser scanner uses laser light to probe the environment or object.
• a trianguiation laser shines a laser on the object and exploits a camera to look for the location of the laser dot. Depending on how far away the laser strikes a surface, the laser dot appears at different places in the camera's field of view. This technique is called trianguiation because the laser dot, the camera and the laser emitter form a triangle.
• a laser stripe instead of a single laser dot, may be used and is then swept across the object to speed up the acquisition process.
• Structured-light 3D scanners project a pattern of light on the object and look at the deformation of the pattern on the object.
• the pattern may be one dimensional or two dimensional.
• An example of a one dimensional pattern is a line.
• the line is projected onto the object using e.g. an LCD projector or a sweeping laser.
• a camera offset slightly from the pattern projector, looks at the shape of the line and uses a technique similar to trianguiation to calculate the distance of every point on the line.
• the line is swept across the field of view to gather distance information one strip at a time.
• An example of a two-dimensional pattern is a grid or a line stripe pattern.
• a camera is used to look at the deformation of the pattern, and an algorithm is used to calculate the distance at each point in the pattern.
• Algorithms for multistripe laser triangulation may be used.
• ICP Iterative Closest Point
• ICP Iterative Closest Point
• the algorithm is conceptually simple and is commonly used in real-time. It iteratively revises the transformation, i.e. translation and rotation, needed to minimize the distance between the points of two raw scans or sub-scans.
• the inputs are: points from two raw scans or sub-scans, initial estimation of the transformation, criteria for stopping the iteration.
• the output is a refined transformation. Essentially the algorithm steps are:
• the present invention relates to different aspects including the method described above and in the following, and corresponding methods, devices, apparatuses, systems, uses, kits 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.
• a method of virtually reducing and milling at least one artificial tooth adapted to be inserted in a denture for a patient where the artificial tooth is provided as a physical artificial tooth and as a corresponding virtual artificial tooth, where the artificial tooth has an original shape, and where the denture is configured to comprise physical artificial teeth and an artificial gingival, wherein the method comprises:
• the physical artificial tooth is adapted to be placed in a milling fixture, such that the arrangement of the physical artificial tooth relative to the milling fixture is known, whereby the determined part of the physical artificial tooth is configured to be cut away by milling, thereby obtaining a reduced physical artificial tooth.
• a fixture for retaining at least one artificial tooth where a part of the artificial tooth is adapted to be cut away by milling in a milling machine thereby obtaining a reduced artificial tooth, where the reduced artificial tooth is adapted to be inserted in a denture for a patient, where the fixture is configured to be arranged in the milling machine for milling the artificial tooth, where the fixture comprises: - at least one cavity, where the shape of the cavity corresponds to at least part of the shape of the artificial tooth; and
• a fixture for retaining a plurality of artificial teeth wherein the fixture is configured to be arranged in a milling machine for milling one or more of the artificial teeth thereby obtaining one or more reduced artificial teeth, where the artificial teeth are adapted to be inserted in a denture for a patient after milling, where the fixture comprises a milling blank, where the plurality of artificial teeth are configured to be retained in the milling blank during milling.
• the milling blank comprises a cavity for each tooth of the plurality of artificial teeth, where the shape of each cavity corresponds to at least part of the shape of the corresponding artificial tooth.
• the fixture can be adapted to releasably retain the artificial tooth or teeth. This advantageously provides a fixture that may be reused.
• the physical artificial tooth is configured to be placed in a milling fixture, such that the arrangement of the physical artificial tooth relative to the milling fixture is known, whereby the determined part of the physical artificial tooth is configured to be cut away by milling in the milling machine, thereby obtaining a reduced physical artificial tooth.
• a system for virtually reducing and milling at least one artificial tooth adapted to be inserted in a denture for a patient where the artificial tooth is provided as a physical artificial tooth and as a corresponding virtual artificial tooth, where the artificial tooth has an original shape, and where the denture is configured to comprise physical artificial teeth and an artificial gingival
• the system comprises: - means for obtaining a 3D digital representation of at least part of the patient's oral cavity;
• the means for obtaining a 3D digital representation may be a processor or circuitry or memmory for transferring or communicating or providing the 3D digital representation, where the digital 3D representation may have been acquired by a 3D scanner, such as an intra oral 3D scanner, a desktop 3D scanner etc.
• a 3D scanner such as an intra oral 3D scanner, a desktop 3D scanner etc.
• the means for virtually designing and virtually determining may be software tools for computer aided design (CAD), including processors etc.
• CAD computer aided design
• the means for providing that the artificial tooth is placed in the milling fixture may be a robot arm arranging the artificial teeth in the fixtures.
• the means for providing that the artificial tooth is cut by milling may be a milling drill, milling cutter etc.
• a system for virtually reducing and milling at least one artificial tooth adapted to be inserted in a denture for a patient where the artificial tooth is provided as a physical artificial tooth and as a corresponding virtual artificial tooth, where the artificial tooth has an original shape, and where the denture is configured to comprise physical artificial teeth and an artificial gingival
• the system comprises: - means for providing that the physical artificial tooth is placed in a milling fixture, such that the arrangement of the physical artificial tooth relative to the milling fixture is known, whereby the determined part of the physical artificial tooth is configured to be cut away by milling; and
• the method(s) and/or system(s) of the present invention may be computer- implemented. Furthermore, the invention relates to a computer program product comprising program code means for causing a data processing system to perform the method according to any of the embodiments, when said program code means are executed on the data processing system, and a computer program product, comprising a computer-readable medium having stored there on the program code means.
• Nontransitory computer readable medium storing thereon a computer program, where said computer program is configured for causing computer-assisted virtual designing of a reduced shape of at least one artificial tooth adapted to be inserted in a denture for a patient, where the artificial tooth is configured to be provided as a physical artificial tooth and as a corresponding virtual artificial tooth, where the artificial tooth is configured to have an original shape, and where the denture is configured to comprise physical artificial teeth and an artificial gingival, wherein: - obtaining a 3D digital representation of at least part of the patient's oral cavity;
• Non-transitory computer readable medium storing thereon a computer program, where said computer program is configured for causing computer-assisted virtual reducing and milling at least one artificial tooth adapted to be inserted in a denture for a patient, where the artificial tooth is provided as a physical artificial tooth and as a corresponding virtual artificial tooth, where the artificial tooth has an original shape, and where the denture is configured to comprise physical artificial teeth and an artificial gingival, wherein: - obtaining a 3D digital representation of at least part of the patient's oral cavity; - virtually designing the denture by virtually designing the artificial gingival and the placement of the artificial teeth in the artificial gingival based on the 3D digital representation of at least part of the patient's oral cavity;
• the system comprises a non-transitory computer readable medium having one or more computer instructions stored thereon, where said computer instructions comprises instructions for carrying out a method of virtually reducing and milling at least one artificial tooth adapted to be inserted in a denture for a patient, where the artificial tooth is provided as a physical artificial tooth and as a corresponding virtual artificial tooth, where the artificial tooth has an original shape, and where the denture is configured to comprise physical artificial teeth and an artificial gingival, wherein the method comprises:
• a method for designing a reduced shape of at least one artificial tooth adapted to be inserted in a denture for a patient where the artificial tooth is configured to be provided as a physical artificial tooth and as a corresponding virtual artificial tooth, where the artificial tooth is configured to have an original shape, and where the denture is configured to comprise physical artificial teeth and an artificial gingival, wherein the method comprises:
• a method for designing a denture comprising an artificial gingiva and at least one reduced physical artificial tooth, wherein the method comprises: - obtaining a 3D digital representation of at least part of the patient's oral cavity;
• the method for designing a denture comprising an artificial gingiva and at least one reduced physical artificial tooth may furthermore comprise that an occlusion is established.
• the occlusion is typically obtained by making a wax rim.
• the oral cavity or two models representing mandible and maxillary of the oral cavity can then be scanned with the wax rim inserted. Based on the virtual model three points may be set and the occlusion plane thus determined by the plane defined by the three points.
• the method for designing a denture comprising an artificial gingiva and at least one reduced physical artificial tooth may furthermore comprise that denture reference points are set.
• Different denture reference points/landmarks can be used. Examples of such point can be specific landmarks such as the central ridge, the canine placement, the retromolar pad and/or tuberosity.
• Fig. 1 shows an example of a flow chart of a method of virtually reducing and milling at least one artificial tooth.
• Fig. 2 shows examples of manufactured dentures.
• Fig. 3 shows examples of virtually designing artificial gingival, a reduced shape of an artificial tooth and the part of an artificial tooth to be cut away to obtain the reduced shape.
• Fig. 4 shows examples of arranging an artificial tooth in a single-tooth fixture for milling a part of the artificial tooth according to a virtual design.
• Fig. 5 shows an example of a multiple-teeth fixture.
• Fig. 6 shows an example of wax fixtures.
• Fig. 7 shows an example of virtually designing a denture.
• Fig. 8 shows an example of a fixture where an inserted artificial tooth can be milled both on the gingival surface and on the incisal/occlusal surface.
• Figs. 9 and 10 shows an example of using the milling blank as feature.
• Fig. 1 1 shows another embodiment of a multiple-teeth fixture.
• Fig. 12 shows an example of a method for designing a denture including the steps of providing reduced artificial teeth as described herein.
• Fig. 1 shows an example of a flow chart of a method of virtually reducing and milling at least one artificial tooth adapted to be inserted in a denture for a patient, where the artificial tooth is provided as a physical artificial tooth and as a corresponding virtual artificial tooth, where the artificial tooth has an original shape, and where the denture is configured to comprise physical artificial teeth and an artificial gingival.
• step 101 a 3D digital representation of at least part of the patient's oral cavity is obtained, for example by means of a 3D scanner.
• step 102 the denture is virtually designed by designing the artificial gingival and the placement of the artificial teeth in the artificial gingival based on the 3D digital representation of at least part of the patient's oral cavity, for example by means of software CAD tools in a software program visualizing the virtual denture on a computer interface.
• step 103 a reduced shape of the artificial tooth is virtually designed, for example also by means of software CAD tools.
• step 104 the part of the artificial tooth to be cut away by milling is virtually determined based on the difference between the original shape of the artificial tooth and the virtually designed reduced shape of the artificial tooth, for example by means of software CAD tools and processor means.
• step 105 the physical artificial tooth is placed in a milling fixture, such that the arrangement of the physical artificial tooth relative to the milling fixture is known, whereby the determined part of the physical artificial tooth is configured to be cut away by milling.
• a person or a robot may for example place the artificial tooth in the fixture.
• step 106 the determined part of the physical artificial tooth is cut away by milling, thereby obtaining a reduced physical artificial tooth. This may be performed by the milling cutter of milling drill in the milling machine.
• the method may be performed at the same physical location or at different physical locations.
• the 3D scanning for obtaining the 3D digital representation of the patient's oral cavity may be performed in a dental clinic by a dentist or a dental assistant.
• the virtual designing and determining may be performed in a dental laboratory by a dental technician.
• the placement of the artificial tooth in the fixture and the cutting of the artificial tooth may be performed in a milling center by a milling machine and/or a milling machine operator.
• Fig. 2 shows examples of manufactured dentures.
• Fig. 2a 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.
• the partial denture is arranged next to a model of the patient's present teeth, and the denture is seen from below, i.e. from the side pointing towards the palate and gums.
• the partial denture is arranged on the model of the patient's teeth, and the denture is seen from above, i.e. from the side pointing towards the surroundings and the antagonist teeth, when the denture is arranged in the mouth of the patient.
• Fig. 2b 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.
• the partial dentures are arranged on the models of the patient's present teeth, and the dentures are seen from above, from the antagonist teeth, or from the frontside.
• the partial dentures are arranged next to the models of the patient's teeth, and the dentures are seen from below, from the gums, or from the backside.
• the dentures are shown without the artificial teeth or the veneering of the metal framework.
• Fig. 2c 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.
• the partial denture is arranged on the model of the patient's present teeth, and the denture is seen from above, from the antagonist teeth, or from the frontside.
• the partial denture is arranged next to the model of the patient's teeth, and the denture is seen from below, from the gums, or from the backside.
• the denture 201 shown in fig. 2c) 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. 2c) is held in place in the patient's mouth by means of friction, suction, negative pressure etc.
• the dentures 201 of fig. 2a) and fig. 2b) 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.
• Fig. 3 shows examples of virtually designing artificial gingival and the part of an artificial tooth to be cut away.
• Fig. 3a shows an example where the artificial tooth 305 is placed in a suitable position in the artificial gingival 303.
• the surface or side of the artificial gingival pointing towards the top of the artificial teeth is called the teeth surface 303a of the artificial gingival 303
• the surface or side of the gingival pointing towards the gums of the patient is called the gum surface 303b of the artificial gingival 303.
• the artificial tooth 305 is so long that it extends through the artificial gingival 303.
• Fig. 3b) shows an example where the gum surface of the artificial gingival 303b is virtually designed to be curved instead of straight as in fig. 3a).
• the curved gum surface 303b of the artificial gingival 303 will follow the gum of the patient, which can be derived from or seen in the 3D representation of the patient's oral cavity (not shown).
• Fig. 3c shows an example where a reduced shape of the artificial tooth 305 is virtually designed and whereby the part of the artificial tooth 305 to be cut away by milling is virtually determined based on the difference between the original shape of the artificial tooth 305 and the virtually designed reduced shape of the artificial tooth 305.
• the reduced shape of the artificial tooth 305 may be virtually designed by manipulating or designing the distance 307, space or gap between the gingival surface 305b of the artificial tooth 305 and the gum surface 303b of the artificial gingival 303.
• the gingival surface 305b of the artificial tooth 305 is the surface or side pointing towards the artificial gingival 303 and the patient's gum when arranged in the mouth of the patient.
• the original, predetermined or default gingival surface 305b of the artificial tooth 305 is the full line 305b, and the modified or virtually designed gingival surface 305b of the artificial tooth 305 is the dotted line.
• the predetermined gingival surface 305b of the artificial tooth 305 is the predetermined shape of the artificial tooth 305.
• the distance 307 between the gingival surface 305b of the artificial tooth 305 and the gum surface 303b of the artificial gingival 303 can be virtually designed by modeling the gingival surface 305b of the tooth 305 and/or by modeling the gum surface 303b of the gingival 303.
• Fig. 3d shows an example of the artificial tooth 305 with the reduced shape, thus the gingival surface 305b of the artificial tooth 305 is shown in the virtually designed position.
• the part of the artificial tooth 305 to be cut away by milling is determining or calculated.
• the reduced shape of the artificial tooth 305 is seen by the different position of the gingival surface 305b of the artificial tooth 305 relative to the gum surface 303b of the artificial gingival 303
• Fig. 4 shows examples of arranging an artificial tooth in a single-tooth fixture for milling a part of the artificial tooth according to a virtual design.
• Fig. 4a shows an example of a single-tooth fixture 408 comprising a cavity 409 for receiving the artificial tooth to be milled.
• the single-tooth fixture 408 can be divided or separated in two parts at the line 410, such that the artificial tooth can be inserted in the cavity 409 irrespective of its shape and any undercuts etc.
• the single-tooth fixture 408 comprises a bore 41 1 configured for receiving a screw to screw the two parts of the single-tooth fixture 409 together when they have been separated at the line 410 and to ensure that the single-tooth fixture 408 retains the artificial tooth in a fixed position.
• Fig. 4b shows an example where the artificial tooth 405 is inserted in the cavity 409 in the single-tooth fixture 408.
• the artificial tooth fits exactly in the cavity 409, because the cavity 409 is specific for that specific model of artificial tooth, i.e. there may exist a single-tooth fixture for each specific model of artificial tooth, where the single-tooth fixture for a specific artificial tooth comprises a specific cavity exactly matching the shape of the artificial tooth.
• a screw 412 is screwed in the bore 41 1 to keep the single-tooth fixture 408 together for retaining the artificial tooth 405.
• Fig. 4c shows an example where the virtually determined part of the artificial tooth 405 to be cut off by milling is indicted by a dotted line 413.
• the cut off line 413 corresponds to the virtually determined gingival surface 405b of the artificial tooth 405 from fig. 3c)
• Fig. 4d shows an example where the part of the artificial tooth 405 has been cut off by milling in a milling machine (not shown), and where the gingival surface 405b of the artificial tooth 405 is now like the virtually designed gingival surface from fig. 3c).
• the physical artificial tooth 405 may now be denoted the adjusted or reduced physical artificial tooth.
• the single-tooth fixture 405 can now be disassembled by unscrewing the screw 412 from the bore 41 1 , and the adjusted artificial tooth can be removed from the single-tooth fixture and be fixed in the artificial gingival of the denture, see fig. 2.
• Fig. 5 shows an example of a multiple-teeth fixture.
• Fig. 5a shows an example of a multiple-teeth fixture 514 from a top-view.
• the multiple-teeth fixture 514 can be a round plate with a cavity 509 for each of the teeth of a complete set of artificial teeth.
• each cavity 509 of the multiple-teeth fixture 514 matches exactly the shape of the specific artificial tooth configured to be inserted in that cavity.
• the cavities 509 are arranged in an arch resembling the position of teeth in the mouth.
• Each cavity is marked with a number on the multiple-teeth fixture corresponding to the tooth number to be inserted in the cavity.
• FIG. 5b shows an example of the multiple-teeth fixture 514 in a cross-section side view.
• a cavity 509 for receiving an artificial tooth to be milled is shown, and the fixture 514 can be disassembled in one or more parts to insert the artificial tooth or teeth by means of separation lines 410.
• one or more screws 512 can be screwed into bores in the fixture 514.
• Fig. 6 shows an example where the artificial teeth are retained in wax fixtures.
• the artificial teeth 605 can be retained in wax fixtures 615, such that each artificial tooth 605 is retained in one wax fixture 615.
• the wax fixtures 615 may be fixed in a plate 616 to be inserted in a milling machine for milling. The milling may be performed such that both the artificial teeth 605 and the surrounding wax fixtures 615 are milled.
• a wax fixture 615 may encompass more or less of the entire artificial tooth 605 and in this case the wax fixture may be disposable, since the wax is adapted to be milled away together with milling the artificial tooth 605.
• a wax fixture 615 may only retain the artificial tooth 605 in a smaller area and in this case the wax fixture may be reusable, since the wax is not milled off together with the artificial tooth.
• Each wax fixture 615 on the plate 616 is marked with a number on the plate such that track can be kept of the different artificial teeth.
• the wax fixture may be fixed in the plate, which may be a milling blank, in cavities in the plate, or the wax fixtures may be attached on the plate by means of glue, adhesion between the wax and the plate etc.
• the cavities may be big enough for accommodating an artificial tooth surrounded by wax.
• Fig. 7 shows an example of virtually designing a denture.
• Fig. 7a shows an example of a digital 3D representation 717 of a patient's oral cavity comprising the gums 718 and the palate 719.
• the patient has no teeth left in this dental arch.
• a set of virtual artificial teeth 705 are arranged relative to the gums 718 and palate 719.
• the boundary of the artificial gingival of the denture is virtually designed by providing or drawing a spline 720 on the digital 3D representation 717.
• Fig. 7b shows an example of a virtually designed denture comprising a virtually designed artificial gingival 703 and the set of virtual artificial teeth 705.
• the arrangement or position of the set of teeth 705 may be further adjusted relative to the artificial gingival 703.
• Fig. 8 shows an example of a fixture where an inserted artificial tooth can be milled both on the gingival surface and on the incisal/occlusal surface.
• the fixture is shown in a cross section side view.
• the fixture can be a multiple-teeth fixture, such as the multiple-teeth fixture shown in fig. 1 1 .
• a cavity 809 for receiving an artificial tooth to be milled is shown, and the cavity is open in both ends such that both the gingival surface of the artificial tooth and the incisal/occlusal surface of the artificial tooth are exposed and can thus be milled in the milling machine.
• the fixture 814 can be disassembled in one or more parts to insert the artificial tooth or teeth by means of separation lines 810. For assembling the fixture 814 and ensuring that it fixedly retains the artificial tooth or teeth, one or more screws 812 can be screwed into bores in the fixture 814.
• Figures 9a - 9c and 10a - 10e describes how to use a milling blank to manufacture a denture base, such as the artificial gingiva as described herein and also use the denture base as a fixture for holding the artificial teeth during milling.
• a milling blank 901 is shown in fig.9a.
• the milling blank is in the shape of a cylinder and is made from a material suitable to use as artificial gingiva.
• a material suitable to use as artificial gingiva can for example be a polymethylmethacrylate ( PSV1MA).
• the milling process is then initiated and the tooth surface 902 of the artificial gingiva is milled.
• the tooth surface 902 of the artificial gingiva is the surface on which the teeth are placed.
• the tooth surface is the surface which during use of the denture faces the opposite jaw.
• the tooth surface 902 has a number of teeth recesses 903 adapted to receive the reduced physical artificial tooth 1010.
• the artificial gingiva 904 may be partially milled as shown in fig.9b or fully milled as shown in fig. 9c in order to proceed to the process as shown in described with respect to figures 10a - 10e.
• the teeth recesses 903 of the tooth surface 902 has been provided it is possible to proceed with the process.
• the entire virtual gingiva 904 will typically be milled as shown in fig. 9c only leaving the sprues 905 which connect it to the remainder of the milling blank. In order to ensure positioning and placement of the artificial gingiva it is kept in the milling blank through the steps which will be discussed with respect to figures 10a - 10e.
• Figures 10a show a virtual setup in a virtual design environment.
• the setup is shown in 2D, but is typically also shown or provided in a 3D workspace.
• a virtual artificial gingiva 1001 has been designed having a tooth recess 1002.
• a CAD-file of a pre-manufactured artificial tooth 1003 is loaded into the design environment and placed by the user so that it fits into the tooth recesses while fulfilling different design rules. Such rules may for example be different estheticai or functional rules.
• a virtual representation of an antagonist tooth 1004 is also shown in the virtual setup and is placed by the user in a preferred position which for example may be determined by similar rules as those used for placing the pre-manufactured artificial tooth 1003. As can be seen, when the user has placed the pre-manufactured artificial tooth 1003 correctly overlaps 1005, 1006 occur between the virtual artificial gingiva 1001 and the antagonist tooth 1004 respectively.
• the user may tell the virtual design environment to section the pre-manufactured artificial tooth 1003 at the gingival surface.
• the user also provides a design modification so that the overlap 1006 with the antagonist tooth 1004 is removed.
• the design modification is a reduction of the pre-manufactured artificial tooth 1003 along a surface represented by the line 1007.
• the design information is then sent to a production facility where the artificial gingiva may be produced as described with respect to figures 9a, 9b and 9c and the pre-manufactured artificial tooth is milled to a reduced size.
• the overlap 1005 is removed as shown in 10b and 10c. This reduction may be done as described previously, for example with respect to figures 4, 5 or 6.
• the reduced pre-manufactured artificial tooth 1010 is placed in the tooth recess 903 in the artificial gingiva 904 as shown in fig. 10d. Since the artificial gingiva is still maintained in the milling blank as previously described its position may easily be determined and the milling machine can remove the overlap 1006 and material down to the surface 101 1 which was defined by the line 1007 in the design step. This results in the final reduced tooth 1012 as shown in fig. 10e. Post-processing finishing may subsequently be applied as necessary, such as polishing shading etc.
• a multiple teeth fixture 1 100 is shown in fig. 1 1 .
• the teeth fixture is specifically designed to hold one type of pre-manufactured library teeth, which in this case is a library totaling sixteen standard artificial teeth.
• the outer dimensions and shape of the teeth fixture corresponds to that of a standard 98mm blank. This allows the teeth fixture to be placed in the corresponding blank holder of a milling machine. After use teeth fixture may be removed and used again later.
• the fixture 1 100 is formed with sixteen through going cavities 1 101 .
• Each cavity is marked with a roman numeral between I - XVI. Although the cavities are shown as circular this should only be representative of their placement.
• Each cavity will have a shape that fits a specific tooth of the teeth library for which the teeth fixture is designed for.
• the fixture is furthermore divided into three parts, a center part 1 102 and a first and second retainer part 1 103, 1 104.
• the cavities lies along the dividing line 1 105 between the center part and the first and second retainer part.
• the artificial teeth When used the artificial teeth are placed in the respective cavities and the first and second retainer part is tightened by screws 1 106,1 107. When tightened the artificial teeth are placed secure and tightly and the fixture may be placed in the milling machine.
• the screws may preferably be unbrako fasteners which is lowered such that the shape of the fixture is not altered.
• the teeth can be milled on both sides, such as previously explained with respect to figure 8.
• a design cycle 1200 for designing and manufacturing is shown in figure 12.
• the occlusion is established to start with in step 1201 .
• This is typically done by manually building a wax rim 1210 which is fitted with gums of the patient, either directly in the oral cavity or in a model of the mandible 121 1 and maxillary 1212.
• the wax rim functions as a spacer keeping the two jaws apart in a distance and positions that provides a good occlusion which is considered esthetic and functional by the dental practitioner.
• the wax rim setup is then scanned and imported into a virtual workspace where the occlusion plane may be determined by placing an intersecting plane between the jaws. The exact placement is provided by the practitioner who places it based on anatomic considerations and experience. The occlusion plane may also be provided otherwise, e.g. by placing three points in different areas which together defines a plane.
• denture reference points are places. These reference points indicate different landmarks that are particularly relevant when designing the denture and determine some basic characteristics of the denture.
• the reference points may for example be a central ridge point 1213 indicating the central ridge, two canine points 1214 showing the optimal placement of the canines and tuberosity points 1215 which indicates particular areas where concern has to be taken to the condition of the bone. However, other types of points may also be provided.
• the virtual gingiva 1216 is designed by drawing the outer boundary of the gingiva 1217.
• a virtual copy of the artificial teeth1218 are in the following step 1204 fitted with the virtual gingiva.
• the reduced shape of the artificial teeth are determined as described herein as it becomes clear which part of the artificial teeth needs to be removed in order for the teeth to fit the gingiva in order to obtain the reduced artificial teeth.
• Final touches may then be applied to the denture in step 1205, such as rugae patterns and similar on the artificial denture.
• step 1206 The artificial gingiva is milled or printed and the reduced artificial teeth are milled from the artificial teeth as described herein.
• the teeth are fitted and attached in the artificial gingiva and the denture is complete.
• 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.
• the described features may be implemented by hardwired circuitry instead of software or in combination with software.
• the offset is zero providing that the gingival surface of the artificial tooth is present on the gum surface of the artificial gingival. 1 1 .
• the part of the artificial tooth to be cut away by milling on the gingival surface of the artificial tooth is at least partly determined by the material properties of the artificial gingival and/or physical artificial tooth.
• the artificial gingival is virtually designed and manufactured comprising a hole for each of the artificial teeth, where the shape of a hole corresponds to the shape of the gingival surface of the respective reduced artificial tooth.
• each of the reduced artificial teeth is adapted to be fixed in the artificial gingival.
• the milling fixture is a standard fixture adapted for receiving different kinds/types of artificial teeth.
• the milling fixture is specific for the artificial tooth.
• the artificial tooth is adapted to be arranged in a cavity in the milling fixture.
• the artificial tooth is adapted to be retained in the milling fixture by means of retention means.
• the milling fixture is a single-tooth fixture.
• the single-tooth fixture is specific for each artificial tooth, such that the shape of the cavity of the specific single-tooth fixture corresponds to at least part of the shape of the specific artificial tooth. 22. The method according to any one or more of the preceding embodiments, wherein the fixture is a multiple-teeth fixture.
• the milling fixture is a wax fixture which is adapted to encompass at least part of an artificial tooth.
• the disposable wax fixture is configured to be milled together with the artificial tooth.
• the 3D representation of the patient's oral cavity is an intra oral scan of at least part of the patient's set of teeth and/or gums, a scan of at least part of an impression of the patient's set of teeth and/or gums, and/or a scan of at least part of a positive physical model of the patient's set of teeth and/or gums.
• the milling blank comprises at least a teeth surface of the artificial gingiva of the denture, wherein said teeth surface is adapted to receive one or more artificial teeth.
• the milling blank is formed of polymethylmethacrylate.
• a computer program product comprising program code means for causing a data processing system to perform the method of any one of the preceding embodiments, when said program code means are executed on the data processing system.
• a computer program product comprising a computer-readable medium having stored there on the program code means.
• a nontransitory computer readable medium storing thereon a computer program, where said computer program is configured for causing computer- assisted virtual designing of a reduced shape of at least one artificial tooth by performing the method of any one or more of the preceding embodiments.
• a nontransitory computer readable medium storing thereon a computer program, where said computer program is configured for causing computer- assisted virtual designing of a reduced shape of at least one artificial tooth adapted to be inserted in a denture for a patient, where the artificial tooth is configured to be provided as a physical artificial tooth and as a corresponding virtual artificial tooth, where the artificial tooth is configured to have an original shape, and where the denture is configured to comprise physical artificial teeth and an artificial gingival, wherein the method comprises:
• the physical artificial tooth is configured to be placed in a milling fixture, such that the arrangement of the physical artificial tooth relative to the milling fixture is known, whereby the determined part of the physical artificial tooth is configured to be cut away by milling in the milling machine, thereby obtaining a reduced physical artificial tooth.
• a non-transitory computer readable medium storing thereon a computer program, where said computer program is configured for causing a computer-assisted method of virtually reducing and milling at least one artificial tooth adapted to be inserted in a denture for a patient, where the artificial tooth is provided as a physical artificial tooth and as a corresponding virtual artificial tooth, where the artificial tooth has an original shape, and where the denture is configured to comprise physical artificial teeth and an artificial gingival, wherein the method comprises:
• a fixture for retaining a plurality of artificial teeth wherein the fixture is configured to be arranged in a milling machine for milling one or more of the artificial teeth thereby obtaining one or more reduced artificial teeth, where the artificial teeth are adapted to be inserted in a denture for a patient after milling, where the fixture comprises a milling blank, where the plurality of artificial teeth are configured to be retained in the milling blank during milling.
• the milling blank comprises at least a teeth surface of an artificial gingiva, wherein said teeth surface is adapted to receive one or more artificial teeth.
• the milling blank is formed of polymethylmethacrylate.
• the milling blank comprises a cavity for each tooth of the plurality of artificial teeth, where the shape of each cavity corresponds to at least part of the shape of the corresponding artificial tooth.
• a method according to embodiment 46 further comprising any of the embodiments 1 - 31 .
• a method for designing a denture comprising an artificial gingiva and at least one reduced physical artificial tooth comprising:

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Cited By (46)

Citations (8)

• 2013
  • 2013-02-22 WO PCT/EP2013/053619 patent/WO2013124452A1/fr not_active Ceased

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