Custom orthodontic appliance forming apparatus

• US 5,683,243 A
• Filed: 06/02/1995
• Issued: 11/04/1997
• Est. Priority Date: 11/09/1992
• Status: Expired due to Term

• Current Assignee: Ormco Corporation (Envista Holdings Corporation)
• Original Assignee: Ormco Corporation (Envista Holdings Corporation)
• Inventors: Payne, Mark A., Andreiko, Craig A.
• Primary Examiner(s): WEHNER, CARY ELLEN
• Application Number:
  US08/456,666
• Time in Patent Office: 886 Days
• Field of Search: 433/2, 433/3, 433/24
• US Class Current: 433/3
• CPC Class Codes: A61C 13/097 characterised by occlusal profiles , i.e. chewing contact surfaces
• CPC Class Codes: A61C 2007/004 Automatic construction of a set of axes for a tooth or a plurality of teeth
• CPC Class Codes: A61C 3/00 Dental tools or instruments implanting tools A61C8/00; tools for fastening artificial teeth A61C13/12; visual inspection devices, e.g. dental mirrors, A61B1/24
• CPC Class Codes: A61C 7/00 Orthodontics, i.e. obtaining or maintaining the desired position of teeth, e.g. by straightening, evening, regulating, separating, or by correcting malocclusions
• CPC Class Codes: A61C 7/002 Orthodontic computer assisted systems
• CPC Class Codes: A61C 7/12 Brackets; Arch wires; Combinations thereof; Accessories therefor
• CPC Class Codes: A61C 7/145 Lingual brackets
• CPC Class Codes: A61C 7/146 Positioning or placement of brackets; Tools therefor
• CPC Class Codes: A61C 7/16 specially adapted to be cemented to teeth
• CPC Class Codes: A61C 7/20 Arch wires A61C7/28 takes precedence
• CPC Class Codes: A61C 9/0046 Data acquisition means or methods
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: G16H 20/40 relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture

Abstract

An apparatus for automatically designing and manufacturing a custom orthodontic appliance from anatomical shape data preferably of the lower jaw and teeth of a patient includes a scanner to produce images in three dimensions, a computer that constructs archforms and calculates finish tooth positions, then automatically designs an appliance, preferably including archwires and brackets, to move the teeth to the calculated positions and jigs to place the brackets on the teeth of the patient, and program controlled machines for making the brackets, wires and jigs to the appliance design driven by commands derived from digitized tooth and jaw shape data.

Claims

1. An apparatus for manufacturing a custom orthodontic appliance, the apparatus comprising:

a scanner for generating data signals containing information of anatomical shapes from an individual patient'"'"'s mouth;

a computer programmed to automatically derive a dental archform for the individual patient, to calculate finish positions of the teeth of the patient in relation to the archform, to calculate a custom orthodontic appliance design for placement on the teeth of the patient to move the teeth of the patient to the calculated finish positions on the derived dental archform, to produce machine readable records of the calculated appliance design;

an automated fabricating machine controlled to respond to the machine readable records to fabricate a custom orthodontic appliance for the individual patient having the calculated custom orthodontic appliance design.

2. The apparatus of claim 1 wherein:

the scanner is operative to generate the data signals to contain information of shapes of the patient'"'"'s teeth and of the shape of the patient'"'"'s lower jaw;

the computer is programmed to automatically derive the dental archform for the individual patient based on the shape of the patient'"'"'s lower jaw and to calculate the finish positions of the teeth of the patient and the custom orthodontic appliance design based at least in part on the shape of the patient'"'"'s teeth.

3. An apparatus for manufacturing a custom orthodontic bracket including a bracket base having a mounting surface securable to a tooth of a patient and an archwire support fixed to and extending from the bracket base and having an archwire receiving slot therein, the apparatus comprising:

a holder having means thereon for mounting a bracket blank thereon for fabrication;

means for recording digital information related to the individual anatomy of the patient that represents the orthodontic positioning of the teeth of the patient;

means for calculating from the digital information the geometry of orthodontic brackets of an orthodontic appliance for orthodontically positioning the teeth of the patient, including calculating geometric relationships of the slots of the brackets to the mounting surfaces of the bracket bases of the respective brackets;

means for forming at least one surface of a bracket blank mounted on the holder in response to a machine control signal communicated thereto; and

means for generating from the calculated bracket geometry and communicating to the forming means a machine control signal for shaping the bracket blank mounted on the holder to produce a bracket having a slot of the calculated geometric relationship to the mounting surface of the bracket base thereof.

4. The apparatus of claim 3 wherein:

each slot includes generally parallel upper and lower sides defining a slot inclination and includes a slot base at an end thereof nearest the bracket base defining a slot position;

each calculated geometric relationship of a slot to the mounting surface of a bracket includes the slot inclination and a slot position relative to the mounting surface; and

the generated machine control signal carries machine control instructions for causing the forming means to shape the bracket blank to produce a bracket having a slot of the calculated slot inclination and slot position with respect to the mounting surface.

5. The apparatus of claim 4 wherein:

the slot of each bracket is adapted to receive an archwire having a custom curvature adjacent the tooth on which the bracket is to be secured; and

each calculated geometric relationship of a slot to the mounting surface of a bracket includes a slot bottom curvature conforming to the custom curvature of the archwire adjacent thereto; and

the generated machine control signal carries machine control instructions for causing the forming means to shape the bracket blank to produce a bracket having a slot of the calculated slot bottom curvature.

6. The apparatus of claim 5 wherein:

the forming means includes means for cutting a slot in the support in response to the control signal;

the calculating means includes means for defining an archwire plane that intersects a bracket when mounted on a tooth; and

the apparatus further comprises means for angularly orienting and translating the holder with respect to the forming means so that the cutting means will operate in response to the control signal to cut a slot in the support of a blank mounted on the holder and lying along the intersection of the archwire plane with the bracket with a slot bottom having the slot bottom curvature.

7. The apparatus of claim 4 wherein:

the calculating means includes means for defining an archwire plane that intersects a bracket when mounted on a tooth; and

the apparatus further comprises means for angularly orienting and translating the holder with respect to the forming means so that the forming means will operate in response to the control signal to cut a slot in the blank mounted on the holder that lies along the intersection of the archwire plane with the bracket with the sides of the slot parallel to the archwire plane at the slot inclination to the mounting surface of the bracket base and to the depth of the slot position with respect to the mounting surface of the bracket base.

8. The apparatus of claim 3 wherein:

the forming means includes means for cutting a slot in the bracket base in response to the control signal.

9. The apparatus of claim 8 wherein:

the forming means includes means for cutting a slot in the bracket blank in response to the control signal; and

the cutting means includes a mechanical slot cutting element moveable with respect to the holder to cut in the bracket blank a slot of the slot inclination and slot position with respect to the mounting surface of the bracket base.

10. The apparatus of claim 8 wherein:

the calculating means includes means for defining an archwire plane that intersects a bracket when mounted on a tooth; and

the apparatus further comprises means for angularly orienting and translating the holder with respect to the forming means so that the cutting means will operate in response to the control signal to cut a slot in the support of a blank mounted on the holder and lying along the intersection of the archwire plane with the bracket with the sides of the slot parallel to the archwire plane at the slot inclination to the mounting surface of the bracket base and to the depth of the slot position with respect to the mounting surface of the bracket base.

11. The apparatus of claim 3 wherein:

the holder and the forming means are mounted on a stand; and

the apparatus further comprises means for angularly orienting the holder with respect to the stand and to the forming means, and means for translating the forming means with respect to the stand and to the holder, in response to the control signal.

12. The apparatus of claim 3 wherein:

means for comparing the geometry of each of the brackets to bracket blank criteria and for selecting therefrom an optimum one of a plurality of bracket blanks for the fabrication of the bracket.

13. A custom orthodontic archwire manufacturing apparatus comprising:

an archwire former including means for forming a length of orthodontic archwire material into a controlled shape in response to a wire shape control signal communicated thereto;

means for producing a digitized record of anatomical shapes of an individual patient'"'"'s mouth; and

a digital computer including program means responsive to the digitized record for deriving digital archwire shape data based on the digitized record, the computer further including means for generating a wire shape control signal in response to the digital archwire shape data, such that, when the signal is communicated to the archwire former, the former will produce a custom orthodontic archwire conforming to the anatomical shape of the individual patient'"'"'s mouth.

14. The apparatus of claim 13 wherein:

the derived digital archwire shape data includes wire length data correlated to a length component of the derived digital archwire shape data and wire curvature data correlated to a curvature component of the derived digital archwire shape data that is a function of the length component;

the wire shape control signal includes a wire feed control signal carrying the wire length data and a wire bending control signal carrying the wire curvature data;

means for generating the wire feed control signal and means for generating a wire bending control signal and communicating the control signals to the archwire former; and

the archwire former includes means for longitudinally feeding the orthodontic archwire material in response to the wire feed control signal and means for transversely bending the archwire material fed by the wire feeding means in response to the wire bending control signal and in synchronism with the feeding of the archwire material.

15. The apparatus of claim 13 wherein:

the digital archwire shape data is a digital representation of a connected series of wire segments, each having a length component and a curvature component; and

the archwire former includes means for longitudinally feeding a series of lengths of the orthodontic archwire material corresponding to the respective wire length components in accordance with the wire length data and means for bending each fed length of archwire material to a curvature corresponding to the respective wire curvature component in accordance with the wire curvature data.

16. The apparatus of claim 15 wherein:

each wire segment is in the form of a circle segment with the length component thereof representing a tangential length of archwire material and with the curvature component thereof representing a constant radius of curvature of the material over the tangential length of the segment; and

the feeding means includes means for longitudinally feeding a series of tangential lengths of the orthodontic archwire material and the bending means includes means for bending each fed length of archwire segment to a constant radius in accordance with the wire curvature data.

17. The apparatus of claim 16 wherein:

the derived digital archwire shape data includes wire length data correlated to a length component of the derived digital archwire shape data and wire curvature data correlated to a curvature component of the derived digital archwire shape data that is a function of the length component;

the wire shape control signal includes a wire feed control signal carrying the wire length data and a wire bending control signal carrying the wire curvature data;

means for generating the wire feed control signal and means for generating a wire bending control signal and communicating the control signals to the forming means;

the feeding means is operative to sequentially feed a series of lengths of the archwire material equal to the length components of the circle segments, in response to the wire feed signal, along a longitudinal path;

the bending means includes a bending element moveable in response to the wire bending control signal transverse to the path to impart a transverse bending deflection to the segment and a transverse position sensor for producing a feedback signal responsive to the deflection; and

the computer includes means for modifying the wire bending control signal in response to the feedback signal to provide closed loop control of the bending element.

18. The apparatus of claim 17 wherein:

the program means includes means in communication with the wire bending control signal generating means for receiving material property data of the archwire material and for modifying the wiring bending control signal in accordance with the property data to compensate for elastic properties of the material.

19. The apparatus of claim 18 further comprising:

means for measuring an archwire span between points on first and last segments of the series of the produced custom orthodontic archwire;

the program means including means for calculating a design archwire span from the derived archwire shape data;

means for comparing the measured archwire span with the design archwire span and for storing the results of the comparison; and

the program means being operative to generate the wire bending control signal in response to a stored result of the comparison.

20. The apparatus of claim 13 wherein:

the program means comprises means for calculating preferred finish positions of the patient'"'"'s teeth from the digitized record and means for deriving the archwire shape data in response to the calculated finish positions; and

the wire shape control signal generating means is operative to generate the wire shape control signal which will produce a custom orthodontic archwire that will urge the teeth toward the calculated finish positions.

21. The apparatus of claim 20 wherein:

the program means includes means for deriving digital orthodontic bracket configuration data that is related to the archwire shape data, to the calculated tooth positions and to the digitized record, for use in the fabrication of orthodontic brackets for connection of the custom archwire in the patient'"'"'s mouth.

22. The apparatus of claim 21 wherein:

the program means includes means for deriving the digital orthodontic bracket configuration data so as to optimize the shape of the archwire to a minimum of curvature inflection points.

23. The apparatus of claim 22 wherein:

the digital archwire shape data is a digital representation of a connected series of wire segments, each having a length component and a curvature component;

each wire segment is in the form of a circle segment the length component thereof representing a tangential length of archwire material and the curvature component thereof representing a constant radius of curvature of the material over the tangential length of the segment; and

the program means includes means for deriving the digital orthodontic bracket configuration data so as to optimize the shape of the archwire to minimize the number of changes in radius from length to length.

24. An apparatus for forming a jig for positioning a bracket of a custom orthodontic appliance on a tooth of a patient comprising:

a jig former including means for shaping the contours of a surface of blank of jig forming material in response to a control signal communicated thereto;

means for providing a digitized record of the shapes of the teeth of a patient and of the locations relative to the tooth shape record of appliance connection points on surfaces of the teeth;

means for calculating, from the digitized tooth shape and connection point record, jig geometry defining a jig locating surface that conforms to a unique portion of the external surface of the crown of a tooth, and defining an appliance engaging surface having the same location relative to the jig locating surface as the unique portion of the external surface has to the connection point on the tooth;

means for generating a machine control signal carrying machine control instructions for producing a jig in accordance with the calculated jig geometry; and

control means for operating jig former in response to the control signal.

25. The apparatus of claim 24 wherein:

the appliance includes a plurality of brackets, one for connection at each connection point to a tooth;

the apparatus further comprises means for providing digitized bracket shape data of an external surface of each bracket to be connected to a connection point; and

wherein the jig geometry calculating means includes means for defining the appliance engaging surface of the jig to conform, in response to the digitized bracket shape data, to the established appliance geometry.

26. The apparatus of claim 25 wherein:

each bracket has an archwire receiving slot therein;

the bracket shape data includes a digital representation of the position and inclination of the slot in the bracket; and

the jig geometry calculating means includes means for defining the appliance engaging surface to include a part thereof that will align with the slot of the bracket when the bracket is engaged thereby.

27. The apparatus of claim 26 wherein:

the appliance engaging surface includes a separate guide member dimensioned to fit in the slot of the bracket and to engage the part of the appliance engaging surface to hold slot of the bracket relative to the jig at a desired position and inclination.

28. The apparatus of claim 24 further comprising:

means for supporting a blank of jig forming material;

the machine includes a cutting tool operative in response to the control signal to cut the defined surfaces of the jig into the blank in accordance with the machine control instructions.