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
  • A61C13/225—Fastening prostheses in the mouth
• • 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
  • A61C5/00—Filling or capping teeth
  • A61C5/70—Tooth crowns; Making thereof
  • A61C5/73—Composite crowns
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C5/00—Filling or capping teeth
  • A61C5/70—Tooth crowns; Making thereof
  • A61C5/77—Methods or devices for making crowns
• • 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

• the present invention concerns a system for dental restorations, in particular, a system for achieving dental restoration components such as bridges, for example.
• a frame When constructing dental components such as bridges, a frame is usually cast in metal after one has made a model of the frame in wax by means of taking an impression of the damaged and prepared area of the patient.
• the frame includes two caps for the accommodation of and attachment at a prepared tooth as well as a beam to hold the caps together.
• the frame can be tested on the patient and adjusted so that it fits before the frame is coated, e.g. with ceramics or plastic, to re-create a tooth or a group of teeth.
• This bridge is attached firmly at two ground- down teeth flanking the damaged area, between which teeth the bridge extends.
• the attachment is carried out by the cap being firmly cemented over the ground-down tooth. If the caps and the beam that joins them together are produced separately, or if the span needs to be adjusted, the separate parts are soldered together edge to edge.
• Numerically-controlled machine tools are used when producing dental bodies such as inserts, caps and crowns today. These usually employ what is known as CAM technology. A crown of the desired shape is built-up in a software program, and with knowledge of the geometry of a worked piece or a blank, the computer can work out a pattern of movements for a known machine tool, usually a milling or grinding tool, that by cutting away at the blank, produces the desired restoration body.
• a known machine tool usually a milling or grinding tool, that by cutting away at the blank, produces the desired restoration body.
• Several ceramic materials have been found to display the characteristics that are advantageous for this application.
• One ceramic that can be ⁇ sed with advantage is zirconium, Zr0 2 .
• Blanks of zirconium ceramic can be produced in several shades of colour that resemble those of teeth and, like several other candidate ceramics, it is a hard material that is very resistant to being worn down. It is therefore possible to produce a solid crown in one piece of this tooth- coloured material.
• Zirconium and similar ceramic materials are, however, not possible to weld or join together in a similar way, which is why ceramic crowns or caps have not been considered for dental components such as bridges and similar. The same also applies for plastics with ceramic-like characteristics.
• Ceramics such as zirconium are desirable materials to use from a biological point of view, but as a consequence of their material characteristics, are difficult and expensive to machine. Furthermore, joining together ceramic components is a problem when one takes into account both precision and durability.
• fig. 1 shows schematically a side view of a bridging component according to one embodiment of the present invention
• fig. 2 shows schematically a perspective view showing separated parts of the bridging component's connection according to fig. 1
• fig. 3 shows a view of the cap according to fig. 1 from underneath
• fig. 4 shows a partially exposed view of an alternative embodiment of the invention.
• Fig. 1 shows schematically a damaged tooth provided with a bridge component according to one embodiment of the invention. Two teeth are missing from the example shown and the adjacent teeth 1 are ground-down so that they can be used as a foundation for the bridge construction according to known techniques.
• the bridging construction includes two caps 2 each arranged to accommodate a ground-down tooth 1 and via a suitable means to be firmly joined to this. This join can be made using cement, glue or other suitable adhesive material.
• a beam 3 intended to support the re-created teeth 4 extends between the caps.
• the replacement teeth can be arranged as one piece with the beam or, as in the present example, be built-up on the beam.
• the beam is provided with what are known as cores 5 at specified positions.
• the replacement teeth 4 are built-up by the core being coated with layers of plastic material or ceramic to achieve the desired shape.
• a similar coating on the caps 2 can in the same way build up the desired shape of the tooth at the ground-down permanent teeth.
• the caps 2 and beam 3 are made in the same ceramic material, zirconium.
• cap 2 is provided with a recess 6 that when observed in the longitudinal direction of the beam, displays an opening with cut-out edges for accommodating the end piece of the beam.
• the end piece of the beam 7 has a complementary shape that fits exactly in the cavity 6, whereby a relatively stable and durable attachment between the beam and the cap is achieved.
• the cap according to fig. 1 and 2 has an internal cavity 8 that is shown schematically in fig. 3 and that is adjusted to and intended for accommodating a prepared ground - down tooth 1.
• This cavity has an essentially vertical longitudinal axis that is parallel with the longitudinal axis of the ground-down tooth.
• cavity 6 for accommodating the end piece of the beam is executed as a vertical groove in the cap, where the groove has an opening 6a in a horizontal direction towards the damaged area and where the opening 6a has cut-out sides.
• the end piece of the beam 7 which is shaped to complement the profile of the groove, is inserted vertically into the groove through the opening inlet 6b of the groove.
• the beam 3 is locked in the direction of insertion when it reaches the bottom of the groove 6.
• the beam is further stabilised in the horizontal direction of oscillation around the cap by it resting against the edges 6c of the opening.
• the turning of the beam around its own axis is limited by the extension of the end piece in the longitudinal direction of the groove.
• the cut-out groove 6 can have a profile that is T-shaped, dove-tailed, circular or some other cut-out shape. Even though a circular shape has shown itself to be sufficiently stable in the present embodiment, a non-circular cross-sectional shape has a greater area in the joint to accommodate the forces from the beam that are active in a perpendicular plane to the longitudinal direction of the groove, the direction of oscillation.
• the end piece of the beam 7 is fixed in the recess or groove, preferably by gluing, cement or similar, or by the connection being coated with ceramic that is then baked.
• the area that is to be restored is first prepared.
• the geometry of the area is described in a manner suitable for a computer, which is also given information about how the restoration body is to look.
• the computer compares the geometrical dimensions of the components with information known about available blanks of known dimensions.
• the blanks can be pre-formed to a larger or lesser extent for individual completion by machining to caps, crowns, beams or other component parts included in the construction.
• the computer then passes instructions to a numerically-controlled machine tool that completes the machining of the chosen blank to the finished component in question.
• the bridge is assembled, fixed in place, reassembled if so required with ceramic or plastic, and thereafter arranged in position in the mouth of the patient.
• the beam blank is pre-formed to include a voluminous part 9 (a part with an extended cross-section), intended for final machining to a replacement tooth 10 directly by the numerically-controlled machining tool.
• a voluminous part 9 a part with an extended cross-section
• the step of building up the shape of the tooth by means of ceramics or similar around a core or direct from a straight beam is avoided.
• the cap can as such, and according to individual wishes, be given an outer shape in the whole range from it just exceeding the prepared tooth to it forming a crown that completely reproduces a tooth.
• the cut-out cavity for the end piece of the beam is executed as a cut-out groove 6 in the area on the side of the crown.
• the groove is executed with an inlet opening 6b that, following the assembly of the end piece of the beam, is sealed with a complementary formed plug 12 in ceramic material, plastic or preferably the same ceramic material in which the crown is made.
• the plug which is partly intended to fill the groove and partly to fill out the crown adjacent to the groove, can be fixed in place by a suitable manner, e.g. by means such as glue, cement, etc.
• the blank for producing a cap or a crown preferably has a pre-formed cavity on its underside where the machining to a shape complementary in relation to the individual prepared tooth for which the cap or crown is intended takes place. Furthermore, the blank for producing a cap or a crown preferably has a pre-formed cut-out cavity or groove for accommodating the end piece of the beam.
• These pre-formed cavities avoid difficulties of making holes or cavities in the surface of the material, which is time-consuming, causes a high degree of wear on the tool and risks forming cracks. Only the final machining, which requires a lesser volume of material to be cut-away, remains in such parts.
• the beam and its end piece can be completed.
• the exact position and shape of the end piece can be determined by the computer and the machining instructions transferred to the machine tool that completes the machining of the chosen blank. If it is wished that the beam should even include whole replacement teeth, a blank available in suitable numbers and sizes is chosen.
• the machine tool produces the beam from the blank and the bridge can be assembled. The building up of the restoration component thus takes place in the computer program. Caps, cores, plugs, tooth shapes, connections, etc. are built-up and adjusted to one another and to the blank available.
• the plug for the groove is preferably made from a pre-formed blank and given its final shape when the shapes of the crown and the end piece of the beam have been fixed.
• the shape of the plug is calculated by the computer using knowledge of the geometry of the adjacent components.

Landscapes

• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Epidemiology (AREA)
• Veterinary Medicine (AREA)
• Animal Behavior & Ethology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Dentistry (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Surgery (AREA)
• Urology & Nephrology (AREA)
• Engineering & Computer Science (AREA)
• Medical Informatics (AREA)
• Primary Health Care (AREA)
• Dental Prosthetics (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20408279

Family Applications (1)

Country Status (3)

Cited By (3)

Citations (2)

• 1997
  • 1997-09-17 SE SE9703354A patent/SE511174C2/sv not_active IP Right Cessation
• 1998
  • 1998-09-17 AU AU92879/98A patent/AU9287998A/en not_active Abandoned
  • 1998-09-17 WO PCT/SE1998/001667 patent/WO1999013797A1/en active Application Filing

Patent Citations (2)

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