(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`(19) World Intellectual Property Organization
`International Bureau
`
`(43) International Publication Date
`1 November 2001 (01.11.2001)
`
`• 1111111111111111 IIIIII 111111111111111 IIIII 111111111111111 IIII IIIIIII IIII IIII IIII
`
`(10) International Publication Number
`WO 01/80761 A2
`
`PCT
`
`(51) International Patent Classification 7:
`
`A61C
`
`(21) International Application Number: PCT/US0l/11969
`
`(22) International Filing Date:
`
`13 April 2001 (13.04.2001)
`
`(25) Filing Language:
`
`(26) Publication Language:
`
`English
`
`English
`
`(30) Priority Data:
`09/552,189
`09/552,190
`09/560,127
`09/560,128
`09/560,129
`09/560,130
`09/560,131
`09/560,132
`09/560,133
`
`19 April 2000 (19.04.2000) us
`19 April 2000 (19.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`
`09/560,134
`09/560,583
`09/560,584
`09/560,640
`09/560,641
`09/560,642
`09/560,643
`09/560,644
`09/560,645
`09/560,646
`09/560,647
`09/613,093
`09/616,093
`09/616,093
`
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`28 April 2000 (28.04.2000) us
`13 July 2000 (13.07.2000) us
`
`(71) Applicant: ORAMETRIX, INC. [US/US]; 12740 Hill(cid:173)
`crest Road, Suite 100, Dallas, TX 75230 (US).
`
`(72) Inventors: ROBBERT, Riidger; Leonhardyweg 41,
`12101 Berlin (DE). WEISE, Thomas; Mehringdamm
`
`[Continued on next page]
`----------------------------------------------
`
`-
`= (54) Title: INTERACTIVE ORTHODONTIC CARE SYSTEM BASED ON INTRA-ORAL SCANNING OF TEETH
`iiiiiiii -iiiiiiii -iiiiiiii
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`I
`I
`I
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`
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`OF'F:Ll\c
`{.e,..,,r
`w,o,Usf,,t•••
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`
`iiiiiiii ----
`
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`
`(57) Abstract: Interactive, computer based orthodontist
`treatment planning, appliance design and appliance
`manufacturing is described. A scanner is described which
`acquires images of the dentition which are converted to
`three-dimensional frames of data. The data from the
`several frames are registered to each other to provide a
`complete three-dimensional virtual model of the dentition.
`Individual tooth objects are obtained from the virtual
`model. A computer-interactive software program provides
`for treatment planning, diagnosis and appliance from the
`virtual tooth models. A desired occlusion for the patient is
`obtained from the treatment planning software. The virtual
`model of the desired occlusion and the virtual model of the
`original dentition provide a base of information for custom
`manufacture of an orthodontic appliance. A variety of
`possible appliance and appliance manufacturing systems
`are contemplated, including customized archwires and
`customized devices for placement of off-the shelf brackets
`on the archwires, and removable orthodontic appliances.
`
`3SHAPE EXHIBIT 1031
`3Shape v. Align
`
`

`

`WO 01/80761 A2
`
`1111111111111111 IIIIII 111111111111111 IIIII 111111111111111 IIII IIIIIII IIII IIII IIII
`
`91, 10965 Berlin (DE). RIEMEIER, Friedrich; Thoma(cid:173)
`siusstrasse 5, 10557 Berlin (DE). SACHDEVA, Ro(cid:173)
`hit; 2605 Courtside Lane, Plano, TX 75093 (US).
`BUTSCHER, Werner; Westfalenring 16b, 12207 Berlin
`(DE). GEERDES, Hans-Florian; Alt-Moabit 73, 10555
`Berlin (DE). IMGRUND, Hans; Wilhelmshavenerstrasse
`25, 10551 Berlin (DE). PFEIL, Lutz; Ander Kolonnade 4,
`10117 Berlin (DE). SPORBERT, Peer; Immanuelkirch(cid:173)
`strasse 29, 10405 Berlin (DE). KOUZIAN, Dimitrij;
`Schlossstrasse 70, 12165 Berlin (DE). LEICHNER,
`Mario; Puschkinallee 95, 16540 Hohen Neuendorf (DE).
`MAETZEL, Stephan; Mittenwalder Strasse 7, 10961
`Berlin (DE). SEE, Peter; Wonnichstrasse 111, 10317
`Berlin (DE). TROEGER, Jens; Ebertystrasse 6, 10249
`Berlin (DE).
`
`(74) Agent: FAIRHALL, Thomas, A.; McDonnell Boehnen
`Hulbert & Berghoff, 300 South Wacker, Suite 3200,
`Chicago, IL 60606 (US).
`
`(81) Designated States (national): AE, AG, AL, AM, AT, AU,
`AZ, BA, BB, BG, BR, BY, BZ, CA, CH, CN, CR, CU, CZ,
`
`DE, DK, DM, DZ, EE, ES, Fl, GB, GD, GE, GH, GM, HR,
`HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR,
`LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ,
`NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM,
`TR, TT, TZ, UA, UG, UZ, VN, YU, ZA, ZW.
`
`(84) Designated States (regional): ARIPO patent (GH, GM,
`KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZW), Eurasian
`patent (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), European
`patent (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE,
`IT, LU, MC, NL, PT, SE, TR), OAPI patent (BF, BJ, CF,
`CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG).
`
`Published:
`without international search report and to be republished
`upon receipt of that report
`
`For two-letter codes and other abbreviations, refer to the "Guid(cid:173)
`ance Notes on Codes and Abbreviations" appearing at the begin(cid:173)
`ning of each regular issue of the PCT Gazette.
`
`

`

`WO 01/80761
`
`PCT/US0l/11969
`
`INTERACTIVE ORTHODONTIC CARE SYSTEM BASED ON INTRA-ORAL
`SCANNING OF TEETH
`
`5
`
`IO
`
`Table of Contents
`
`Background of the Invention ............................. ,_.: .... 2
`
`Summary of the invention ............................. : ....... 8.
`
`Brief Description of the Drawings .............................. 15
`,,
`15 Detailed Description of the Preferred Embodiment .: ........ ,, .. i ..... 27
`
`'
`
`Part 1. System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
`
`Part 2. Three-Dimensional Image Capture ................. 34
`
`Scanner Manufacture and Calibration . . . . . . . . . . . . . . 36
`
`Pattern Recognition. . . . . . . . . . . . . . . . . . .. . . . . . . . . 46
`
`20
`
`Decoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
`
`Derivation of 3-D Point Cloud per Image . . . . . . . . . . . 52
`
`Part 3. Generation of Digital Impression . . . . . . . . . . . . . . . . 54
`
`Entry Point into Registration . . . . . . . . . . . . . . . . . . . . 57
`
`Frame to Frame Registration . . . . . . . . . . . . . . . . . . .
`
`5 8
`
`25
`
`Cumulative Registration of Entire Jaw............ 64
`
`Segment registration . . . . . . . . . . . . . . . . . . . . . . . . .
`
`69
`
`Landmarking................................ 70
`
`Separation of Teeth into Individual Tooth Objects ... 72
`
`Part 4. Treatment Planning . . . . . . . . . . . . . . . . . . . . . . . . . . 82
`
`30
`
`Part 5. Appliance Manufacturing . . . . . . . . . . . . . . . . . . . . 101
`
`Robot Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
`
`Archwire manufacture . . . . . . . . . . . . . . . . . . . . . . . 112
`
`Claims........... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
`
`Abstract............... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
`
`I
`
`

`

`WO 01/80761
`
`PCT/US0l/11969
`
`BACKGROUND OF THE INVENTION
`
`A. Field of the Invention
`
`5
`
`This invention relates generally to the field of orthodontics. More particularly, the
`
`invention relates to a computerized, interactive method and associated system for
`
`orthodontic treatment. The system includes a hand-held optical scanner capturing 3-
`
`dimensional information of objects, interactive computer-based treatment planning using
`
`three-dimensional tooth objects and user. specified simulation of tooth movement, and
`
`10
`
`appliance manufacturing apparatus, including bending machines.
`
`B. Description of Related-Art
`
`In orthodontics, a patient suffering from a malocclusion is typically treated by
`
`bonding brackets to the surface of the patient's teeth. The brackets have slots for receiving
`
`15
`
`an archwire. The bracket-archwire interaction governs forces applied to the teeth and
`
`defines the desired_ direction of tooth movement. _Typically, the bends in the wire are made
`
`manually by the orthodontist. During the course of treatment, the movement of the teeth is
`
`monitored. Corrections to the br,_acket position and/or wire shape are made manually by the
`
`orthodontist.
`
`2
`
`

`

`WO 01/80761
`
`PCT/US0l/11969
`
`The key to efficiency in treatment and maximum quality in results is a realistic •
`
`' ,.
`
`~
`
`'
`
`simulation of the treatment process. Today's orthodontists have the possibility of talcing-
`
`plaster models of the upper and lower jaw, cutting the model into single tooth models and
`
`sticking these tooth models into a wax bed, lining them up in the desired position, the so-
`
`5
`
`called set-up. This approach allows for reaching a perfect occlusion without any guessing.
`
`The next step is to bond a bracket at every tooth model. This would tell the orthodontist the
`
`geometry of the wire to run through the bracket slots to receive exactly this result. The next
`
`step involves the transfer of the bracket position to the original malocclusion model. To
`
`make sure that the brackets will be bonded at exactly this position at the real patient's teeth,
`
`10
`
`small templates for every tooth would have to be fabricated that fit over the bracket and a
`
`relevant part of the tooth and allow for reliable placement of the bracket on the patient's
`
`teeth. To increase efficiency of the bonding process, another option would be to place each
`
`single bracket onto a model of the malocclusion and then fabricate one single transfer tray
`
`per jaw that covers all brackets and relevant portions of every tooth. Using such a transfer
`
`15
`
`tray guarantees a very quick and yet precise bonding using indirect bonding.
`
`However, it is obvious that such an approach requires an extreme amount of time
`
`and labor and thus is too costly, and this is the reason why it is not practiced widely. The
`
`normal orthodontist does not fabricate set-ups; he places the brackets dir~ctly on the
`
`patient's teeth to the best of his knowledge, uses an off-the-shelf wire and hopes for the
`
`20
`
`best. There is no way to confirm whether the brackets are placed correctly; and
`
`misplacement of the bracket will change the direction and/or magnitude of the forces
`
`imparted on the teeth. While at the beginning of treatment things generally run well as all
`
`teeth start to move at least into the right direction, at the end of treatment a lot of time is lost
`
`by adaptations and corrections required due to the fact that the end result has not been
`
`25
`
`properly planned at any point of time. For the orthodontist this is still preferable over the
`
`lab process described above, as the efforts for the lab process would still exceed the efforts
`
`that he has to put in during treatment. And the patient has no choice and does not know that
`
`treatment time could be significantly reduced if proper planning was done.
`
`3
`
`

`

`WO 01/80761
`
`PCT/US0l/11969
`
`U.S. Patent 5,431,562 to Andreiko et al. describes a computerized, appliance-driven
`
`approach to orthodontics.
`
`In this method, first certain shape information of teeth is
`
`acquired. A uniplanar target archfonn is calculated from the shape information. The shape
`
`of customized bracket slots, the bracket base, and the shape of an orthodontic archwire, are
`
`5
`
`calculated in accordance with a mathematically-derived target archfonn. The goal of the
`
`Andreiko et al. method is to give more predictability, standardization, and certainty to
`
`orthodontics. by replacing the human element in orthodontic appliance design with a
`
`deterministic, mathematical computation of a target archfonn and appliance design. Hence
`
`the '562 patent teaches away from an interactive, computer-based system in which the
`
`10
`
`orthodontist remains fully involved in patient diagnosis, appliance design, and treatment
`
`planning and monitoring.
`
`More recently, in the late 1990's Align Technologies began offering transparent,
`
`removable aligning _devices as a new treatment modality in orthodontics.
`
`In this system, a
`
`plaster model of the dentition of the patent is obtained by the orthodontist and shipped to a
`
`15
`
`remote appliance manufacturing center, where it is scanned with a laser. A computer
`
`model of the dentition in a target situation is generated at the appliance manufacturing
`
`center and made available for viewing to the orthodontist over the Internet. The
`
`orthodontist indicates changes they wish to make to individual tooth positions. Later,
`
`another virtual model is provided over the Internet and the orthodontist reviews the revised
`
`20 model, and indicates any further changes. After several such iterations, the target situation
`
`is agreed upon. A series of removable aligning devices or shells are manufactured and
`
`delivered to the orthodontist. The shells, in theory, will move the patient's teeth to the
`
`desired or target position.
`
`4
`
`

`

`WO 01/80761
`
`PCT/US0l/11969
`
`The art has lacked an effective, computer-based interactive orthodontic treatment
`
`planning system that provides the necessary tools to allow the orthodontist to quickly and
`
`efficiently design a treatment plan for a patient. The art has also lacked a treatment
`
`planning system in which the orthodontist-derived parameters for the treatment can be
`
`5
`
`translated into a design of an orthodontic appliance in real time, while the patient is in the
`
`chair. Real-time appliance design as described herein also allows for real-time
`
`communication of the treatment plan or appliance design to occur with the patient, or
`transmitted over a communications link and shared with a colleague or remote appliance
`
`manufacturing facility. Alternatively, the treatment planning can be performed remotely
`
`10
`
`and a digital treatment plan sent to the orthodontist for review, interactive modification, or
`
`approval.
`
`Scanners are devices for capturing and recording information from a surface of an
`
`object. Scanners for obtaining information from a two-dimensional surface, such as reading
`
`bar codes or characters printed on a piece of paper, are widely known. Several scanners
`
`15
`
`have been proposed for recording three-dimensional information as well, including the field
`
`of dentistry.
`
`U.S. Patent 4,837,732 and U.S. Patent 4,575,805 to Brandestini and Moermann
`
`propose a scanning system for in vivo, non-contact scanning of teeth. The patents describe a
`
`procedure for optically mapping a prepared tooth with a non-contact scan-head. The scan-
`
`20
`
`head delivers the contour data, converted to electrical format, to be stored in a memory. A
`
`computer reads the memory following a line scan pattern. A milling device is slaved to
`
`follow this pattern by means of position control signals and mills an implant for the
`
`prepared tooth cavity.
`
`The scan-head of the '732 and '805 patents includes a light emitting diode, with
`
`25
`
`integral lens that radiates light onto the cavity. Before reaching the object, the rays of light
`
`are reflected by a mirror and pass through a ruling consisting of a plurality of parallel slits,
`
`or an alternating pattern of parallel opaque and transparent stripes. The reflected light is
`
`focused by a lens onto a charge-coupled device (CCD) sensor. Depth information is
`
`30
`
`determined in accordance with a principle known as "active triangulation," using parameters
`shown in Figure 9 of this document and described subsequently. Basically, the object is
`viewed under an angle different from the incident rays due to a parallax effect. Each light
`
`stripe will have an apparent positional shift and the amount of the shift at each point along
`
`5
`
`

`

`WO 01/80761
`
`PCT/US0l/11969
`
`each light stripe is proportional to the vertical height of the corresponding portion of the
`
`surface on the object.
`
`U.S. Patent No. 5,372,502 to Massenet al. describes an optical probe for measuring
`
`teeth that works on a similar principle. As noted in the Massen et al. patent, the Brandestini
`
`5
`
`et al.
`
`tecwJJ_qu,e is difficult to use when there are large variations in surface topography
`
`since such large jumps displace the pattern by an amount larger than the phase constant of
`
`the pattern, making it difficult to reconstruct the pattern of lines. Furthermore, precise
`
`knowledge of the angle: of incidence and angle of reflection; and the separation distance
`
`between the light source and the detector, are needed to make accurate determinations of
`
`10
`
`depth. , Furthermore, the scanner has to be rather c,arefully positioned with respect to the
`
`tooth,and would be;} unable to make a complete model o~the dentition.
`
`U.S. Patent Nos. 5,027,281 to Rekow et al. describes a scanning method using a
`
`three axis positioning head with a laser source and detector, a rotational stage and a
`
`computer controller. The computer controller positions both the rotational stage and the
`
`15
`
`positioning head. An object is placed on the rotational stage and the laser beam reflects
`
`from it. The reflected laser b~am is used to measure the distance between the object and the
`
`laser source. X and Y coordinates are obtained by movement of the rotational stage or the
`
`positioning head. A three-dimensional virtual model of the object is created from the laser
`
`scanning. The '281 patent describes using this scanning method for scanning a plaster
`
`20
`
`. model of teeth for purposes of acquiring shape of the teeth to form a dental prosthesis. The
`
`system of the '281 patent is not particularly flexible, since it requires the object to be placed
`
`on the rotational stage and precise control of the relative position of the object and the
`
`positioning head is required at all times. It is unsuited for in vivo scanning of the teeth.
`
`U.S. Patent 5,431,562 to Andreiko et al. describes a method of acquiring certain
`
`25
`
`shape information of teeth from a plaster model of the teeth. The plaster model is placed
`
`on a table and a picture is taken of the teeth using a video camera positioned a known
`
`distance away from the model, looking directly down on the model.
`
`The image is
`
`displayed on an input computer and a positioning grid is placed over the image of_ the teeth.
`
`The operator manually inputs X and Y coordinate information of selected points on the
`
`30
`
`teeth, such as the mesial and distal contact points of the teeth. An alternative embodiment is
`
`described in which a laser directs a laser beam OJ.J.to a model of the teeth and the reflected
`
`beatn is detected by a sensor. The patent asserts; that three-dimensional infonnation as to
`
`teeth can be_ acquired from this techmque but does not explain how it would be done.
`
`

`

`WO 01/80761
`
`PCT/US0l/11969
`
`Neither of the techniques of Andreiko have met with widespread commercial success or
`
`acceptance in orthodontics.
`
`Neither technique achieves in vivo scanning of teeth.
`
`Moreover, the video technique does not produce complete three-dimensional information as
`
`to the teeth, but rather a limited amount of two-dimensional information, requiring
`
`5
`
`significant manual operator input. Even using this technique, additional equipment is
`
`required even to describe the labial surface of a tooth along a single plane.
`
`The art has also lacked a reliable, accurate, low-cost, and easily used scanning
`
`system that can quickly and automatically acquire three-dimensional information of an
`
`object, without requiring substantial operator input, and in particular one that can be held in
`
`10
`
`the hand and used for in vivo scanning or scanning a model. The present invention meets
`
`this need.
`
`7
`
`

`

`WO 01/80761
`
`PCT/US0l/11969
`
`SUMMARY OF THE INVENTION
`An interactive, orthodontic care system is provided based on scanning of teeth. The
`
`system includes a hand-held scanner and associated processing system for capturing images
`
`of the dentition of the patient and processing the images to generate a full, virtual, three-
`
`s
`
`dimensional model of the dentition. A data conditioning system processes the virtual, three(cid:173)
`
`dimensional model and responsively generates a set of individual, virtual three-dimensional
`
`tooth objects representing teeth in the dentition of the patient A workstation is provided
`
`having a user interface for display of the set of individual, virtual three-dimensional tooth
`
`objects. Interactive treatment planning software is provided on the workstation permitting a
`
`10
`
`user to manipulate the virtual three-dimensional tooth objects to thereby design a target
`
`situation for the patient in three dimensions and parameters for a customized orthodontic
`
`appliance for the teeth.
`
`The hand-held scanner and associated processing system, data conditioning system,
`
`and workstation may all ·be installed in an orthodontic clinic. Alternatively, the hand-held
`
`15
`
`scanner and workstation are installed in an orthodontic clinic, and wherein the data
`
`conditioning system is installed in a general purpose computer at a remote location from
`
`orthodontic clinic. Further, the treatment planning software can be either installed at the
`
`clinic, and/or at a remote location, and/or at a precision appliance manufacturing center that .
`
`manufactures a custom orthodontic appliance.
`
`The type of appliance may vary
`
`20
`
`considerably.
`
`The treatment planning apparatus can be considered an interactive, computer-based
`
`computer aided design and computer aided manufacturing (CAD/CAM) system for
`
`orthodontics. The apparatus is highly interactive, in that it provides the orthodontist with
`
`the opportunity to _both observe and analyze the current stage of the patient's condition and
`
`25
`
`develop and specify a target or desired stage. A shortest direct path of tooth movement to
`
`the target stage can also be determined. Further, the apparatus provides for simulation of
`
`tooth movement between current and target stages .
`
`. In its broader aspects, the apparatus comprises a workstation having a processing
`
`unit and a display, and a memory storing a virtual, complete three-dimensional model
`
`30
`
`representing the dentition of a patient. The virtual three-dimensional model can be obtained
`
`from one of several possible sources; in the preferred embodiment it is arrived at from a
`
`scanning of the dentition.
`
`The apparatus further includes software executable by the
`
`processing unit that accesses the model and displays the model on the display of the
`
`8
`
`

`

`WO 01/80761
`
`PCT/US0l/11969
`
`workstation. The software further includes navigation tools,· e.g., typed commands, icons
`
`and/or graphical devices superimposed on the displayed model, that enables a user to
`
`manipulate the model on the display and simulate the movement of at least one tooth in the
`
`model relative to other teeth in the model in three-dimensional space, and quantify the
`
`5
`
`amount of movement precisely. This simulation can be used, for example, to design a
`
`particular target situation for the patient.
`
`The development of a unique target situation for the patient has utility in a variety of
`
`different orthodontic appliances, including an approach based on off-the-shelf or generic
`
`brackets and a custom orthodontic archwire. The scope of the invention is sufficient to
`
`10
`
`encompass other types of appliances, such as an approach based on customized brackets,
`In a bracket embodiment, the memory contains a
`library of virtual, three-dimensional orthodontic brackets. The software permits a user to
`
`retainers, or removable aligning devices.
`
`access the virtual brackets through a suitable screen display, and place the virtual brackets
`
`on the virtual model of the dentition of the patient. This bracket bonding position can be
`
`15
`
`customized on a tooth by tooth basis to suit individual patient anatomy. Because the tooth
`
`models, brackets and archwire are individual objects, and stored as such in memory, the
`
`treatment planning apparatus can simultaneously display the virtual brackets, the archwire
`
`and the virtual model of the dentition, or some lesser combination, such as just the brackets,
`
`just the dentition, or the brackets and the archwire but not the teeth.
`
`The same holds
`
`20
`
`true with other appliance systems.
`In a preferred embodiment, the virtual model of teeth comprises a set of virtual,
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`individual three-dimensional tooth objects. A method of obtaining the tooth objects from a
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`scan of teeth, and obtaining other virtual objects of associated anatomical structures, e.g.,
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`gums, roots and bone is described. When 'the teeth are separated from each other and from
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`the gums, they can be individually manipulated. Thus, the individual tooth objects can be
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`individually selected and moved relativ~ to other teeth in the set of virtual tooth objects.
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`This feature permits individual, customized tooth positioning on a tooth by tooth basis.
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`These positioning can be in terms or angular rotation about three axis, or translation in
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`transverse, sagittal or coronal planes. Additionally, various measurement features are
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`30
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`provided for quantifying the amount of movement.
`
`One of the primary tools in the treatment planning apparatus is the selection and
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`customization or a desired or target archform. Again, because the teeth are individual tooth
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`· objects, they can be moved independently of each other to define an ideal arch. This
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`development pf the target archform could be calculated using interpolation or cubic spline
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`algorithms. Alternatively, it can be customized by the user specifying a type of archform
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`(e.g, Roth), and the tooth are moved onto that archform or some modification of that
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`archform. The arcpf orm can be shaped to meet the anatomical constraints of the patient.
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`5 After the initial archform is designed, the user can again position the teeth on the archform
`
`as they deem appropriate on a tooth by tooth basis. The treatment planning software thus
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`enables the movement of the virtual tooth objects onto an archform which may represent, at
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`least in part, a proposed treatment objective for the patient.
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`Numerous other features are possible with the treatment planning software,
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`10
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`including movement of the teeth with respect to the other teeth in the archform, changing
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`the position of the virtual brackets and the teeth with respect to each other, or opposing teeth
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`with respect ot the selected archform. Custom archwire bends can be simulated to provide
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`additional corrections. Bonding corrections at the bracket-tooth interface are also possible.
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`In another aspect of the invention, a method is provided for digital treatment
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`15
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`planning for an orthodontic patient on a workstation having a processing unit, a user
`
`interface including a display and software executable by the processing unit. The method
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`comprises the steps of obtaining and storing a three-dimensional virtual model of teeth
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`representing the dentition of the patient in a current or observed situation. The virtual model
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`is displayed on the display. The method further includes the step of moving the position of
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`teeth in the virtual model relative to each other so as to place the teeth of the virtual model
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`into a target situation and displaying the virtual model with the teeth moved to the target
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`situation to the user. Parameters for an orthodontic appliance to move the patient's teeth
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`from the current situation to the target situation can be derived from the virtual model and
`''
`the targ~t situation. For example, if virtual brackets are.placed on the teeth, their location
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`in the target situafioJ:?. can dictate the design of an archwire to move the teeth to the target
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`situ1;1,tion.
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`The scanner system is provided for capturing three-dimensional information of an
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`object. The object can be virtually any object under scrutiny, however the present document
`
`will describe an application in which the object is the dentition of a patient suffering from a
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`30 malocclusion.
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`The scanning system enables threea.dimensional surface information to be obtained
`
`with a very high decree of precision. Moreover, the scanning system can be used without
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`requiring precise movement of the scanner, or requiring the object under scrutiny to be fixed
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`in space.
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`Surprisingly, the scanner is able to generate precise three dimensional surface
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`information by simply moving the scanner over the surface of the object, such as by hand, in
`
`any manner that is convenient for the user, even if the object moves in any random direction
`
`during the scanning within reasonable limits. Thus, the scanner can be used to capture the
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`5
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`surface of a patient's dentition in a minute or two, even if the patient moves their head or
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`jaw while the scanning is occurring. Precise knowledge of the spatial relationship between
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`the scanner and the object is not required.
`
`The scanner obtains a set of images, which are processed in a computer to calculate
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`the surface configuration of the object in three dimensions of space automatically, quickly,
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`10 with high precision, and with essentially no human involvement other than the act of
`
`scanning. The precision or accuracy will be dictated largely by the extent to which the
`.
`object under scrutiny tends to h~ve undercut or shadowed features which are difficult to
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`.
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`. detect, necessitating a narrow angle between the projection and imaging axes. For teeth, an
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`accuracy of under 20 or 30 microns .is possible. This accuracy can be further improved
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`15
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`depending on the nature of the surface, such as if the surface does not have a lot of undercut
`
`or shadowed features, by increasing the angular separation of the projection axis and the
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`imaging axis.
`
`Each image captured by the scanner is converted· to a virtual, three-dimensional
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`point cloud or "frame.'' The illustrated embodiment has a relatively coarse resolution for
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`20
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`any single frame, due to a coarse projection pattern, but a fine resolution is obtained by
`
`obtaining multiple images and performing a registration procedure on the frames, as
`
`described below. Since each point on the surface of the object is captured in a plurality of
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`images ( such as five or six in a typical example of scanning), the registration of frames
`
`results in a fine resolution. An even finer resolution can be obtained by scanning slower and
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`25
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`capturing more images of the surface of the object from different perspectives and
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`registering the resulting frames to each other.
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`This surface configuration of the object in three dimensions of space can be
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`represented as a mathematical model, i.e., a virtual model of the object, which can be
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`displayed on any workstation or computer using available software tools.
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`The
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`30 mathematical model can be viewed in any orientation in space, permitting detailed analysis
`of the surface. The model can be compared to template objects stored in a computer.
`
`Deviations in the object from the template can be quantified and analyzed. Further, the
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`virtual model can be transported from one computer and another computer anywhere in the
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`world essentially instantaneously over communications links such as the Internet. The
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`model can be replicated in a computer and thus shared and used by multiple users
`
`simultaneously.
`
`The scanner system is useful for a wide variety of industrial, medical, archeological,
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`5
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`forensic, archival, or other purposes. Furthermore, the scanner can be scaled down in size
`
`such that it can be hand-held and used to scan small objects, e.g., teeth or small machined
`
`parts, or scaled up in size so that it can be used to make mathematical models of larger scale
`objects such as works of art, sculptures, -archeological sites { e.g., the caves at Lascaux,
`
`France or the dwellings or kivas in Mesa Verde National Park), rooms or building facades.
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`10
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`In accordance with a preferred embodiment, the scanner system includes a projection
`
`system that projects a pattern onto the object along a first optical axis. The pattern may
`
`consist of parallel lines, parallel lines separated by shapes or colors, such as colored dots, or
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`other suitabl~ pattern. The projected pattern is used to gather information as to the surface
`
`characteristics of the object in accordance with the methods and procedures described in
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`15 more detail below: . ··
`
`The scanner further in