(12) United States Patent
`MacDougald et al.
`
`1111111111111111111111111111111/ lllll lllll lllll lllll lllll llllll llll llll llll
`US006568936B2
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 6,568,936 B2
`May 27, 2003
`
`(54) METHOD AND APPARATUS FOR
`PREPARING DENTAL RESTORATIONS
`
`(75)
`
`Inventors: Joseph A. MacDougald, Madison, CT
`(US); Carlino Panzera, Hillsborough,
`NJ (US)
`
`(73) Assignee: Pentron Laboratory Technologies,
`LLC.
`
`( *) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U .S.C. 154(b) by 0 days.
`
`(21) Appl. No.: 09/754,887'
`
`(22) Filed :
`
`Jan. 5, 2001
`
`(65)
`
`Prior Publication Data
`
`US 2001/0034010 Al Oct. 25, 2001
`
`Related U.S. Application Data
`Provisional application No. 60/174,543, filed on Jan. 5,
`2000.
`Int. Cl.7
`..... .• . . ..• ..• •.. . . .. . •. . ...•.. . . . . . ... . .. . . . . . . . A61C 5/10
`.......................... ......... ..... 433/223; 433/214
`U.S. Cl .
`Field of Search ............... .................. 433/226, 214,
`433/215, 223, 213
`
`Rcforcnccs Cited
`
`U.S. PATENT DOCUMENTS
`
`3,861,044 A
`4,182,312 A
`4,575,805 A
`•
`4,837,732 A
`4,935,635 A •
`
`1/1975 Swinson, Jr.
`1/1980 Mushabac
`3/1986 Moermann el al.
`6/1989 Brandeslini el al. ... .... . 433/223
`6/1990 O' Hara ...... ............... .. 433/214
`
`12
`
`(60)
`
`(51)
`(52)
`(58)
`
`(56)
`
`10
`
`5,017,139 A
`5/1991 Mushabac
`5,027,281 A
`6/1991 Rekow et al.
`5,092,022 A
`3/1992 Durel
`5,121,333 A
`6/1992 Riley el al.
`5,121,334 A
`6/1992 Riley et al.
`7/1992 Erdman et al.
`5,128,870 A
`5,184,306 A
`2/1993 Erdman el al.
`5,224,049 A
`6/1993 Mushabac
`5,257,184 A
`10/1993 Mushabac
`5,257,203 A
`10/1993 Riley et al.
`5,266,030 A
`11/1993 Van Der Zel
`5,273,429 A
`12/1993 Rekow et al.
`8/1994 Mushabac
`5,343,391 A
`• 12/1994 Ma~sen cl al. .............. 433/215
`5,372,502 A
`5,382,164 A • 1/1995 Stern ......... ... .............. 433/213
`5,440,496 A
`8/1995 Andersson et al.
`5,545,039 A
`8/1996 Mushabac
`5,569,578 A
`10/1996 Mushabac
`7/1997 Andersson et al.
`5,652,709 A
`5,674,073 A
`10/1997 Ingber et al.
`5,690,490 A
`11/1997 Cannon el al.
`* cited by examiner
`Primary Examiner-Cary E. O'Connor
`(74) Attorney, Agent, or Firm-Ann M . Knab
`
`(57)
`
`ABSTRACT
`
`A method and apparatus for producing dental restorations
`for teeth that need to be restored. In the process, a first set
`of data points is retrieved from a tooth or an image of the
`tooth to be restored. The tooth is prepared by the dentist and
`a second set of data points is retrieved from the tooth or an
`image of the tooth. The second set of points is compared to
`the first set of points lo obtain a third sel of points. The dental
`restoration is milled from dental material based on the image
`resulting from the third set of data points.
`
`9 Claims, 1 Drawing Sheet
`
`exocad GmbH, et. al.
`Exhibit 1009
`
`0001
`
`

`

`May 27, 2003
`May 27, 2003
`
`US 6,568,936 B2
`US 6,568,936 B2
`
`FIG.2
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`a /
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`"¢
`N
`4
`N
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`26
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`N
`N
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`22TO
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`0
`N
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`0002
`0002
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`U.S. Patent
`U.S. Patent
`
`5 I
`
`hele2=
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`+
`
`FIG.1
`
`-o
`
`0
`O
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`

`

`US 6,568,936 B2
`
`1
`METHOD AND APPARATUS FOR
`PREPARING DENTAL RESTORATIONS
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`
`This application claims priority lo U.S. Provisional Appli(cid:173)
`cation No. 60/174,543, filed Jan. 5, 2000, which is incor(cid:173)
`porated herein by reference.
`
`FIELD OF THE INVENTION
`
`The present invention relates generally to a method and
`apparatus for producing dental restorations using CAM/
`CAD procedures.
`
`BACKGROUND OF THE INVENTION
`
`2
`or an image produced from the tooth or teeth in the patient's
`mouth to provide data that represents the scanned teeth. The
`apparatus further includes a mechanism for comparing lwo
`sets of data from the scanning device aad calculating a third
`5 set of data. The apparatus may include a machining device
`or the machining device may be a separate device. The
`machining device reads and interprets the third set of data
`and mills dental material, such as metal or ceramic material,
`into a dental restoration representative of the image provided
`10 from the third set of data points.
`The apparatus produces a three-dimensional body that is
`a dental restoration such as an orthodontic appliance, bridge,
`space maintainer, tooth replacement appliance, splint,
`crown, partial crown, denture, post, tooth, jacket, inlay,
`15 onlay, facing, veneer, facet, implant, abutment, cylinder, or
`connector.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`Features of the present invention are disclosed in the
`accompanying drawings, wherein similar reference charac(cid:173)
`ters denote similar elements throughout the several views,
`and wherein:
`FIG. 1 is a schematic diagram of the representations
`achieved from the various sets of data in the manufacture of
`an iolay in accordance with the process herein; and
`FIG. 2 is a schematic diagram of the representations
`achieved from the various sets of data in the manufacture of
`a crown in accordance with the process hernin.
`
`A number of methods involving the production of dental
`restorations and prosthetic devices are known in the art.
`Generally, a tooth is drilled to remove one or more defects.
`An impression is taken of the tooth and surrounding teeth. 20
`A master model is then created from the impression by
`pouring a gypsum die material in lo the cured impression and
`allowing it to harden. A wax pattern with a sprue is prepared
`on the die, hardened, removed from the die and invested in
`a refractory material. The wax is then "burned out" and a 25
`refractory pattern is created into which a metal or ceramic
`material is then cast to provide the desired dental restorative
`material.
`Alternatively, if the lost wax process is not used, a
`working or duplicate die must be prepared from the original 30
`impression or from a duplicate impression made from the
`master model, both processes involving pouring a refractory
`into the impression to create the die. Metal or ceramic
`material is then built onto the die and the die with the
`material thereon is sintered to provide the dental restoration. 35
`The above procedures are time consuming and often
`costly due to laboratory fees. Computer assisted design and
`milling machines have been introduced in the industry and
`are starting to make an impact. Although many of the
`above-mentioned steps may be reduced with the computer
`assisted tools, there remains a need to further simplify the
`processes. U.S. Pat. No. 5,690,490 is directed to a method
`and apparatus for fabrication of a dental restoration by
`pinhead molding. The method requires that impressions be
`taken and placed in a laser scanning box, wherein laser
`scanning is conducted within a controlled environment. The
`process is time consuming in that it requires two sets of
`impressions to be taken and thereafter scanned.
`It is desirable that dental restorations be formed from 50
`images taken directly from the mouth. It is preferable that
`the restorations duplicate the original shape of the restored
`tooth as closely as possible.
`
`40
`
`DESCRIPTION OF THE INVENTION
`As will be appreciated, the present invention provides a
`method for producing dental restorations that closely
`resemble the original contour and shape of the tooth or teeth
`prior to the occurrence of decay or damage thereto. FIG. 1
`schematically illustrates the steps undertaken to achieve the
`final restoration. In FIG. 1, a tooth 10 is to be fitted for an
`onlay. A scanning device such as a probe is moved along
`tooth 10 to obtain a set of data that represents the three(cid:173)
`dimensional contour and shape of tooth 10. Any currently
`available scanning or data gathering device may be used
`such as those set forth in U.S. Pat. Nos. 4,182,312, 4,575,
`805, 5,257,184, 5,343,391, 5,454,039, and 5,569,578, all of
`which are hereby incorporated by reference. Optionally,
`photographs may be taken or a model may be produced of
`the tooth to be treated. The photographs or model are then
`converted into a set of data that represenl~ the contour and
`shape of the tooth. In all methods, the data is collected on the
`tooth prior to any preparation of the tooth.
`Frequently, the tooth to be treated already bas some
`defects thereon which change the original shape of the tooth .
`FIG. 2 shows a tooth 20 having a defect 22 thereon. In such
`a case, the same tooth in the adjacent quadrant is used as the
`"target" tooth to obtain the data corresponding to the contour
`55 and shape of the tooth. Alternately, the damaged tooth may
`be used as the target tooth, but the data obtained will then be
`modified to correct the defects thereon. This may be per(cid:173)
`formed by using a computer to "build up" that section of the
`tooth which is damaged lo provide a profile that represents
`60 a fully restored or original, unaltered tooth. If there is a
`missing tooth which needs a restoration, data may be
`obtained from the adjacent teeth, the same tooth in the
`adjacent quadrant, and occlusion teeth to provide an image
`most similar to the missing tooth. The tooth in the adjacent
`65 quadrant will provide the overall general shape. The adja(cid:173)
`cent teeth will assist in providing the contour and shape of
`the proximal surfaces of the mis.~ing tooth and the occlusion
`
`45
`
`SUMMARY OF THE INVENTION
`These and other objects and advantages are accomplished
`by a method of producing dental restorations for teeth that
`need to be restored. In the process, a first set of data points
`is retrieved from a tooth or an image of the tooth to be
`restored. The tooth is prepared by the dentist and a second
`set of data points is retrieved from the tooth or an image of
`the tooth. The second set of points is compared to the first
`set of points to obtain a third set of points. The dental
`restoration is milled from dental material based on the image
`resulting from the third set of data points.
`In an apparatus herein, a scanning device such as a probe
`is provided lo scan the tooth or teeth in the patient's mouth
`
`0003
`
`

`

`US 6,568,936 B2
`
`10
`
`3
`teeth will assist in providing the contour of the occlusal
`surface of the teeth.
`1be accumulation of the data points corresponding to lhe
`original tooth will provide the information necessary lo form
`the external surface of the restoration. Any sensing or 5
`scanning device may be used to perform this step such as an
`optical scanner, a probe scanner, a laser scanner or a tactile
`scanner.
`After all of the material data regarding the original tooth
`has been collected, the tooth may be prepared by the dentist.
`This may include removing the damaged part of the tooth
`which may involve removing the enamel and dentition from
`the tooth. FIGS. 1 and 2 show prepared teeth 12 and 24.
`Tooth 12 has been prepared by removing material from the
`upper middle area of the tooth and forming a groove 14 15
`therein. Mure area was needed lo be removed from Louth 24
`which represents a small tooth stump. After the dentist has
`prepared the tooth, the prepared tooth is scanned for contour
`and shape to obtain a set of data points which represents the
`three-dimensional contour and shape of the prepared tooth. 20
`This set of data is used to form the internal surface or inside
`of the restoration which attaches to the tooth in the mouth.
`The set of points obtained from the original tooth (first set
`of points) and the set of points obtained from the prepared 25
`tooth (second set of points) are compared to obtain a set of
`points (third set of points) which provides lhe shape of lhe
`restoration to be fabricated . Mathefi:!atically, the data from
`the prepared tooth is subtracted from the data of the original
`tooth to provide data which forms an image which image is 30
`then used lo fabricate the restoration used to restore the
`prepared tooth to the shape of the original tooth, or more
`precisely, the restoration will fit onto the prepared tooth to
`provide a tooth which mimics the original tooth.
`FIGS. 1 and 2 show restorations 16 and 26, respectively, 35
`which are formed from the result obtained by subtracting the
`prepared Louth data from Lhe original tooth data. 1be data
`obtained from this equation is used to create the restoration.
`The restoration may be machined by any suitable technique,
`including electro-erosion, laser cutting, ultrasonic material 40
`removal, milling, grinding and/ or drilling such as those
`techniques set forth in U.S. Pat. Nos. 5,121,333 and 5,184,
`306, which arc hereby incorporated by reference. The mate(cid:173)
`rial used to fabricate the restoration may be any suitable
`dental material including alloys, metals, composites, ceram- 45
`ics and glass-ceramics.
`The interior of the restoration may be reduced in size in
`order to allow for adhesive materials, such as luting and
`bonding materials, to be applied to the interior of the
`restoration prior to insertion on the tooth. This may be 50
`performed prior to fabrication by reducing the size of the
`interior using the computer. The process herein may utilize
`computer assisted design and computer assisted milling
`techniques and equipment which are adapted to perform the
`steps of the invention.
`In the apparatus herein, a scanning device such as a probe
`is provided to scan the tooth or teeth in the patient's mouth
`or to scan an image produced from the tooth or teeth in the
`patient's mouth to provide data that represents the scanned
`teeth. The apparatus further includes a computer for com- 60
`paring two sets of data received from the scanning device
`and calculating an error function between the first and
`second set of data to provide a third set of data. The
`apparatus may include a machining device or the machining
`device may be a separate device. The machining device
`
`55
`
`4
`reads and interprets the third set of data and mills dental
`material, such as metal or ceramic material, into a dental
`restoration representative of the image provided from the
`third set of data points.
`While various descriptions of the present invention are
`described above, it should be umlerslood that the various
`features can be used singly or in any combination thereof.
`Therefore, this invention is not to be limited to only the
`specifically preferred embodiments depicted herein.
`Further, it should be understood that variations and modi(cid:173)
`fications within the spirit and scope of the invention may
`occur to those skilled in the art to which the invention
`pertains. Accordingly, all expedient modifications readily
`attainable by one versed in the art from the disclosure set
`forth herein that arc within the scope and spirit of the present
`invention are to be included as further embodiments of the
`present invention. The scope of the present invention is
`accordingly defined as set forth in the appended claims.
`What is claimed is:
`1. A method for producing a three-dimensional body
`comprising:
`scanning a first tooth to obtain a first set of data;
`preparing a second tooth;
`scanning the prepared tooth to obtain a second set of data;
`calculating the dilTerence between !ht: first set of data and
`the second set of data to obtain a third set of data;
`producing a three-dimensional body from the third set of
`data.
`2. The method of claim 1 wherein the first tooth is a target
`tooth which provides a model of an original shape of the
`second tooth.
`3. The method of claim 2 wherein the preparing step
`comprises reducing the enamel on the tooth.
`4. 1be method of claim 3 wherein the preparing step
`further comprises reducing the dentition on Lhe tooth.
`5. The method of claim 2 wherein the scanning steps
`comprise using a scanner selected form a probe scanner, a
`tactile scanner and an optical scanner.
`6. The method of claim 2 wherein the producing step
`comprises using a technique selected from electro-erosion,
`laser cutting, ultrasonic material removal, milling, grinding
`and drilling to create the three-dimensional body.
`7. The method of claim 2 wherein the three-dimensional
`body is a restoration selected from an orthodontic appliance,
`bridge, space maintainer, tooth replacement appliance,
`splint, crown, partial crown, denture, post, tooth, jacket,
`inlay, onlay, facing, veneer, facet, implant, abutment,
`cylinder, and connector.
`8. A restoration prepared by the method comprising:
`scanning a first tooth to obtain a first set of data;
`preparing a second tooth;
`scanning Lhe prepared tooth lo obtain a second set of data;
`calculating Lbe diJierence between the first set of dala and
`the second set of data to obtain a third set of data;
`producing the restoration from the third set of data.
`9. The restoration of claim 8 selected from an orthodontic
`appliance, bridge, space maintainer, tooth replacement
`appliance, splint, crown, partial crown, denture, post, tooth,
`jacket, inlay, onlay, facing, veneer, facet, implant, abutment,
`cylinder, and connector.
`
`* * • * *
`
`0004
`
`

`

`UNITED STATES PATENT AND TRADEMARK OFFICE
`CERTIFICATE OF CORRECTION
`
`PATENT NO.
`DATED
`INVENTOR(S)
`
`: 6,568,936 B2
`: June 13, 2003
`: Joseph A MacDougald and Carlino Panzera
`
`Page 1 of 1
`
`It is certified that error appears in the above-identified patent and that said Letters Patent is
`hereby corrected as shown below:
`
`Title page,
`Item [73], Assignee, delete the Assignee "Pentron Laboratory Technologies, LLC"
`and replace with -- Jeneric/Pentron Incorporated--.
`
`Signed and Sealed this
`
`Ninth Day of September, 2003
`
`JAMES E. ROGAN
`Director ofthr. United Stares Patent and Trademark Office
`
`0005
`
`

`

`UNITED STATES PATENT AND TRADEMARK OFFICE
`CERTIFICATE OF CORRECTION
`
`PATENT NO.
`DATED
`INVENTOR(S)
`
`: 6,568,936 B2
`: December 9, 2003
`: Joseph A. MacDougald and Carlino Panzera
`
`Page 1 of 1
`
`It is certified that error appears in the above-identified patent and that said Letters Patent is
`hereby corrected as shown below:
`
`Column 1,
`Lines 13 and 14, delete "CAM/CAD" and replace with -- CAD/CAM--.
`
`Signed and Sealed this
`
`Third Day of February, 2004
`
`JONW.DUDAS
`Acting Director of the United States Patenc and Trademark Office
`
`0006
`
`

`

`UNITED STATES PATENT AND TRADEMARK OFFICE
`CERTIFICATE OF CORRECTION
`
`PATENT NO.
`DATED
`INVENTOR(S)
`
`: 6,568,936 B2
`: May27, 2003
`: Joseph A MacDougald and Carlino Panzera
`
`Page 1 of 1
`
`It is certified that error appears in the above-identified patent and that said Letters Patent is
`hereby corrected as shown below:
`
`Column l,
`Lines 13 and 14, delete "CAM/CAD" and replace with -- CAD/CAM--.
`
`Signed and Sealed this
`
`Twenty-fourth Day of February, 2004
`
`JONW.DUDAS
`Acting Director of the United States Pacem and Trademark Office
`
`0007
`
`