Patent Publication Number: US-2005142517-A1

Title: System for producing a dental implant and method

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      This application is a continuation-in-part of U.S. patent application Ser. No. 10/749,579 filed Dec. 30, 2003 entitled “Laser Digitizer System for Dental Applications”, and a continuation-in-part of U.S. patent application Ser. No. 10/804,694 filed Mar. 19, 2004 entitled “Laser Digitizer System for Dental Applications”, and a continuation-in-part of U.S. patent application Ser. No. 10/840,480 filed May 5, 2004 entitled “Optical Coherence Tomography Imaging”, and a continuation-in-part of U.S. patent application Ser. No. 10/917,069 filed Aug. 12, 2004 entitled “Improved Milling Machine”, the complete disclosures of which are incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION  
      1. Related Field  
      The invention relates to dental implants and systems and methods for producing and preparing dental implants.  
      2. Description of the Related Art  
      A dental implant may be inserted into the jawbone of a patient to provide a foundation for a dental prosthesis that replaces a missing tooth. Conventional implants are often comprised of titanium or titanium coated material and are generally elongated cylindrical screw-like devices which have outer threads to engage with the jawbone and a hollow inner-portion for receipt of a mating abutment. Dental implants provide a foundation for the dentist to place an artificial tooth or crown in order to restore dental function to the patient.  
      Integration of the bone to the implant is an important aspect of implant securement and positioning. One or more dental burs are used by a dentist (or other surgical specialist) to prepare the site in the jawbone for placement of the implant. The implant is then placed into the prepared site or surgical site formed in the jawbone and a sealing screw may be placed in the implant. After the implant is placed, there is a healing period of approximately three to six months in order for the jawbone to grow around and fuse with the implant by a process known as osseointegration. Once the implant is secured in the jawbone, an abutment member (or post) is attached to the implant. The abutment joins the implant and a dental prosthesis (such as an artificial tooth or crown) and functions as the support for the dental prosthesis. Once the prosthesis is made, after dental impressions are taken, the prosthesis is fitted and attached to the abutment extending from the implant.  
      One early form of dental implantation employed blade implants made of chrome cobalt type metal. To place these blade implants, the dentist prepares a groove into exposed bone in a mesial distal direction. The blades are generally thicker than the formed groove and are tapped into place ensuring a tight fit. The blades also have a projection coming out of the bone into the oral cavity to support the prosthesis. At times, problems occur with such blade implants due to epithelium growing between the blade and the bone as a result of micromotion or overheating of the bone during preparation, incorrect texture of the surface, or placement of the blade in less dense cancellous bone.  
      When conventional implants are placed into a healed extraction site, the healed site is usually shrunken resulting in the healed area having a smaller volume especially in the bucco lingual and occlusal apical dimensions. This often provides a challenge of using an implant of the correct size in length and diameter in order to provide the strength to bear the load. Additionally, when placing an implant into a healed extraction site, the dentist drills a hole into exposed bone under very specific conditions of speed and cooling so as not to overheat the bone. Then, depending on the implant selected, the implant is either tapped or screwed into place. The success of the implant is dependent on the close fit of the implant to the bone and the stability of the implant so that the bone can grow and integrate directly with the implant.  
      When a fresh extraction has taken place, the placement of an implant often poses a challenge. This is due to the socket or void in the bone being much longer than most implants and even when larger or expandable implants are employed, they periodically have difficulty properly integrating with the bone. Additionally, conventional implantation involving fresh extraction often requires preparation that is apical to the extraction site which tends to be a more invasive procedure.  
      One implanting approach that is used after a tooth is removed at a fresh extraction site involves placing freeze-dried bone into the socket and placing a membrane over the socket to stop soft tissue from growing over and into the socket. This prevents the socket space from collapsing and allows healthy bone to accept a conventional implant. Another approach is to prepare a hole for receipt of the implant that is deeper than the socket in order to stabilize the implant. Freeze-dried bone is then placed between the implant and the bone and a membrane is placed over the opening to the socket. This invasive approach requires a high degree of training, involves high cost and requires a lengthy healing time.  
     SUMMARY OF THE INVENTION  
      Embodiments of a system and a method for producing a dental fixture having a dental implant are provided. A laser digitizer imaging system creates a visual three-dimensional image of a dental item such as a tooth or a dental impression. The three-dimensional image may be displayed and the size and shape of the image may be selectively modified by the user of the dental implant production system. Data associated with the three-dimensional image of the dental item is sent from the laser digitizer imaging system to an implant production device. A dental implant is produced in response to receipt of the data associated with the three-dimensional image. The dental implant may mimic the shape of a root portion of the tooth such that the produced implant is insertable into a socket of the jawbone from where the tooth was removed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a block diagram of a dental implant production system.  
       FIG. 2   a  illustrates a top view of one example of a laser digitizer imaging system for dental applications.  
       FIG. 2   b  illustrates a front view of the exemplary laser digitizer imaging system of  FIG. 2   a  for dental applications.  
       FIG. 3  illustrates an image of a light pattern of the laser digitizer imaging system of  FIGS. 2   a  and  2   b,  as viewed on a flat surface.  
       FIG. 4  illustrates the light pattern of  FIG. 3  as projected on a dental tooth to be imaged.  
       FIG. 5  illustrates a reflection of the light pattern of  FIG. 3  as detected by image capture instrument.  
       FIG. 6  illustrates an embodiment of an object positioner of the laser digitizer imaging system of  FIGS. 2   a  and  2   b.    
       FIG. 7  illustrates an example of an intra-oral laser digitizer imaging system for dental applications.  
       FIG. 8  illustrates an example of an intra-oral laser digitizer imaging system configured as an optical coherence tomography (“OCT”) or confocal sensor.  
       FIG. 9  is a perspective view of an example implant production device.  
       FIG. 10  is a perspective view of a carriage of the implant production device of  FIG. 9  that controls x-axis movement of spindles.  
       FIG. 11  is a cut-away view of a spindle showing a collet that engages a cutting tool.  
       FIG. 12  is a perspective view of a sub-assembly that controls the y-axis and z-axis of the implant production device.  
       FIG. 13  illustrates an example of imaging a tooth and producing a dental implant.  
       FIG. 14  illustrates an example imaging a tooth having a curved root portion and producing a dental implant.  
       FIG. 15  is a flow chart illustrating an example of the steps of producing a dental implant from a dental item. 
    
    
     DETAILED DESCRIPTION  
       FIG. 1  illustrates an example of a dental implant production system  100  configured to generate a three-dimensional image  110  of a dental item such as a tooth  120  and for producing a dental implant  130  from the image obtained from the tooth. The dental item may alternatively be a dental impression formed from inserting impression material into a socket at an extraction site from where a tooth was removed. The dental impression formed is imaged and a dental implant is produced from data associated with the image of the dental impression. Other dental items may include bridges, inlays, crowns, onlays, copings, frameworks, veneers and the like. The dental implant production system  100  includes an imaging system  140 , display device  150 , user interface  160 , and implant production device  170 . The dental implant production system  110  may also include an object positioner  180  to hold and position an extracted tooth or other dental item  120  within a field of projection of the imaging system  140 . Alternatively, an intra-oral imaging system may be used to image the dental item such as a tooth  120  (as well as adjacent teeth) from the mouth of the patient (in vivo) before extraction.  
      The imaging system  140  may be a laser digitizer imaging system having a scanner which optically scans a portion of the tooth  120 . For instance, the imaging system  140  will optically scan the tooth  120  in order for the dental implant  130 , formed at the implant production device  170 , to be insertable into the socket of a patient&#39;s jawbone that previously held the tooth. As an example only, the description herein discusses imaging and production of an implant from data associated with the image of the tooth. However, it is understood that imaging of a dental impression or other dental items may be performed in producing the dental implant. The imaging system  140  receives reflected light signals upon scanning the tooth  120  and creates a three-dimensional image  110  of the portion of the tooth  120  being scanned. Some portions of the tooth  120  may be obscured due to shadowing effects or areas where the projected light cannot reach. In order to obtain full coverage, multiple three-dimensional images are obtained from suitable vantage points in order to represent the entire surface area of the tooth  120 . The imaging system  140  captures data by imaging reflected light and computes three-dimensional data which describes the surface of the portion of the tooth  120  being imaged. If multiple images are obtained, the images are combined into a single three-dimensional combined image by transforming each image according to known transformation parameters, or transforming each image so that common areas between the images are aligned. A display device  150 , such as a cathode ray tube (CRT) device, computer monitor, computer system and display, display screen, or other suitable display device is coupled with the imaging system  140  and displays the three-dimensional image  110  of the tooth  120  for viewing by the user of the dental implant production device  100 .  
      User interface  160  coupled with the imaging system  140  allows the user (such as a dentist or other dental professional) to modify the shape and size of the image obtained in order for the implant production device  170  to produce a dental implant  130  in accordance with the modifications made. The user interface  160  may be a keyboard, mouse, touch pad, touch screen, track-ball, screen actuation probe, slider, or any other suitable interface to convey information to the imaging system. The implant production device  170  is coupled to the imaging system  140  and receives data associated with the three-dimensional image  110  of the tooth from the imaging system. For example, the implant production device  170  may receive data which may include standard tool-path data as commonly used by commercial CNC milling machines. The tool-path data may instruct cutting tools of a particular size and shape at the implant production device  170  to machine a block of material into a shape which corresponds to the three-dimensional image  110  of the tooth from the imaging system  140 . Alternative forms of analog or digital data may also be employed to produce a dental implant from the imaged tooth.  
      The implant production device  170  produces the dental implant  130  in response to receipt of the data associated with the three-dimensional image  110 . The user may also selectively design a dental prosthesis such as a dental crown to be inserted on the dental implant, preferably at an abutment extending from the implant. In some instances, imaging of neighboring or opposing teeth, or both, may be performed using an intra-oral laser digitizer imaging system ( FIGS. 7, 8 ) for performing in vivo imaging of the teeth when designing a dental crown prosthesis. Once the particular design for the dental crown is made by the user interacting with the imaging system  140 , a temporary crown, formed from a composite block placed at production device  170 , may be milled for placement upon a dental implant.  
      The implant production device  170 ,  FIG. 1 , in one example, may be a milling machine which is programmable to mill a solid piece of material to form the dental implant  130  based on data received from the imaging system  140 . The milled material may be a titanium block; however, other suitable biocompatible materials may be employed. The implant production device  170  forms the dental implant  130  to mimic the shape of the tooth  120  that was imaged. In particular, the implant production device  170  is capable of forming the dental implant to mimic the original shape of the root portion  122  (or a portion thereof) of the tooth  120  such that the implant  130  may be tapped into position and seated in a fresh socket of the jawbone from where the tooth was extracted.  
      In order to optimize the implantation procedure, the size and shape of the images taken from the tooth  120  can be adjusted by the imaging system  140  based on user input. The implant production device  170  produces the dental implant  130  in accordance with such adjustments and modifications to meet the desired specifications of the user (e.g. dentist). For instance, the user interface  160  allows the actual size of the three-dimensional image  110  to be selectively adjusted by the user inputting information related to the size modification into the imaging system  140 . In order to create stability in the bone, and also prevent soft tissue from entering the cavity socket, and to provide a tight fit, the thickness of the occlusal third (the upper portion of the implant) or some other portion can be made larger (relative to the corresponding occlusal third portion of the imaged root which was in the bone), depending on the site, and age group of a patient. If the root portion  122  of the tooth is curved, the curved portion is typically found at the apical third of the root. A tight fit in the fresh socket of the jawbone at the occlusal third of the inserted implant will act to prevent migration of soft tissue into the cavity. Thus, depending on the shape of a tooth having a curved portion at its root  122 , the user may elect to forego reproducing the curved portion of the root, as seen in  FIG. 14 , in the titanium block by making appropriate adjustments via user interface  160  to the three-dimensional data obtained for the imaged tooth  110 . If a curved root portion is not produced for the implant  130 , bone will grow into the void in the socket apical to the root after the implant is inserted into the socket.  
      If the length of the root  122 ,  FIG. 1 , of the imaged tooth  120  is long, such that an inserted implant  130  would be close to a critical nerve or other structure, the length of the implant  130  to be formed may be changed or shortened by adjusting the three-dimensional data associated with the imaged tooth  110  to avoid encroaching on critical anatomical sites such as inferior alveolar nerve or the sinus cavity. Thus, if the tooth has a root that is undesirably long or is curved making insertion of an implant with such a curved shape difficult, the three-dimensional data associated with the root portion of the tooth image may be modified such that a corresponding root portion  136  of the dental implant  130  may be omitted by the implant production device  170 , as seen in  FIG. 14 . The data associated with the three-dimensional image of the root portion of the tooth is truncated. The implant production device  170 ,  FIG. 1 , accordingly will not mill the full length of the root in accordance with the tool-path data that is generated from the modified three- dimensional data. In multi-rooted teeth, one or more of the roots  122  may selectively be imaged and formed in the produced dental implant  130  depending on the situation. Imaging of the roots  122  may selectively be done separately, because the roots may be divergent.  
      If the root  122  of the tooth  120  being imaged is fractured or broken so that it cannot be digitized, an accurate dental impression material may be placed and pressed into the socket to form a dental impression. An impression may also be made of a prepared site, in which the socket has been prepared after a tooth extraction. In this case, the original socket may not be optimal for an implant, and additional modification is made to the socket prior to producing an impression of the socket. In one example, the dental implant may be produced by extracting a tooth from the mouth of a patient and then various dental procedures may be performed at the socket from where the tooth was removed to create a prepared site. Impression material is then inserted into the prepared site to form the dental impression and the dental impression (or a portion thereof) is imaged by imaging system  140 . The dental impression is then digitized and the same procedure is followed as for an intact root of a tooth. Once the data has been captured by the imaging system  140 , it is presented on the display device  150  to the user, who may manipulate the three-dimensional data associated with the displayed image  110  via the user interface  160 .  
      The implant production device  170  will then produce the dental implant  130  that may selectively have a size that is different than the size of the tooth  120  being imaged. The user, for example, may desire the tooth shaped dental implant  130 , or a portion thereof, to be slightly larger (e.g. 2 mm) than the original size of the corresponding tooth portion  120 , in order for the dental implant to fit tightly in the socket created in the mouth of the patient. The dental implant  130 , or portions thereof, may, for example, selectively be formed to be 0%-30% larger than the original size of the corresponding portion of the tooth  120 . For instance, the user may desire to make the occlusal third (or portions thereof) of the implant 10% or more larger than the corresponding portion of the tooth being imaged to optimize a secure fit in the socket. Alternatively, apical portions of the implant such as root portions may be formed to have a size that is the same (or shortened in length) relative to the corresponding apical portion of the tooth. The user inputs the selected size adjustment at the user interface  160  and the imaging system  140  is programmed to make the modification to selected portions of the image  110 . The shape of the socket may be modified by controlled preparation by drilling small holes into the cortical bone (and not overheating the bone), in order to improve blood supply and aid acceptance of the implant produced by the implant production device  170 . It may be necessary to lengthen the socket in order to optimize the implantation.  
      The user may also selectively utilize user interface  160  to direct the imaging system  140  to modify the surface of the three-dimensional image  110  obtained. Modifications to the size of the upper portion of the three dimensional image  110  may be made by means of a user interface element in the user interface  160  (such as a slider or other similar control) which allows for the user to selectively and interactively change the size of the three-dimensional root model. If the user desires to truncate the apical portion of the root of the three-dimensional image  110 , for example, due to excessive length or curvature, user interface elements in the user interface  160  are provided to effect this change on the display device  150  interactively. An example of a user interface would be a slider which allows the user to choose a range (such as 0-30%) which instructs software operating at the imaging system  140  the extent to which the size modifications need to be made. Alternatively, user interface  160  interacting with imaging system  140  may provide selection of regions of the three dimensional data (generating displayed image  110 ) using a mouse, cursor or similar interface allowing for interaction with and modification of the displayed image  110 . In this way, regions in the three dimensional data associated with the displayed image  110  may be selected and then modified. The modifications on the selected portions of the image may include truncation, scaling, or other geometric modifications.  
      The user may also utilize the user interface  160  to modify the texture of the surface of the three-dimensional image  110 . In this way, the implant  130  produced by the implant production device  170  may have a surface texture or quality that is optimal for the application. The computer controlled imaging system  140  may modify or eliminate a portion of the tooth imaged or change the particular contour of the tooth image in response to user input at the user interface  160 . One example of a user interaction may include use of a three-dimensional data viewer which allows the user to view the data set associated with the displayed image from all vantage points. The user interface  160  operating with imaging system  140  may also include tools to view the three dimensional data along any predefined axis. The user interface may also include a mechanism interacting with imaging system  140  to identify the principal axis of a tooth root, and to display the principal axis.  
      The computer controlled imaging system  140  may also provide indication to the user, by means of shading or other means displayed on display device  150 , of which portions of the three dimensional data may pose a problem. For example, if the root is very long or curved, so that it would be difficult or not appropriate to insert an identical solid machined metal implant into the socket, then operable software at the computer controlled imaging system  140  may identify which portions of the lower part of the displayed image  110  and corresponding implant should be truncated. The user interface  160  operating with imaging system  140  may include tools to enable cross sectional views of the three dimensional data.  
      Regions on the three-dimensional data may be detected automatically by the software running at imaging system  140 , or chosen by the user. Automatic detection may include the automatic identification of the occlusal portion of the root, so that it may be scaled in size in the correct range so as to effect a tight and stable fit for the final implant. Manual selection may include standard three-dimensional software selection schemes, through the use of direct interaction with the three-dimensional data by means of keyboard commands, mouse or trackball motions by themselves, and in combination with various keyboard combinations. User modification tools may be offered through a toolbar or menu displayed on display device  150 , which provide such utilities as automatic detection of regions, automatic scaling or modification of selected regions (according to parameters defined in another user interface element), and automatic truncation or deletion of portions of the three dimensional data associated with the imaged tooth.  
      Once the desired size and shape are selected and the appropriate modifications are made to the image  110  being displayed, the imaging system  140  transmits data associated with the tooth image to the implant production device  170 . In one example, the computer controlled imaging system  140  calculates and generates tool path data to be received at implant production device  170  based on the three-dimensional data for the modified image. Alternatively, the modified three-dimensional data may be sent from the imaging system  140  to the implant production device  170  that converts the three-dimensional imaging data to tool path data that provides milling instructions at the implant production device. The implant production device, such as a milling machine which mills an inserted titanium block, responsively produces the dental implant  130  having a size and surface contour associated with the modified image  110  of the tooth.  
      Once the user has modified the three-dimensional image  110  to his satisfaction, the data associated with the modified image may be sent to the implant production device  170 . In one example, the implant production device  170  has one or more spindles with attached cutting or grinding tools or burs. Depending on the size, shape and configuration of the cutting tools or burs, the programming at the computer based implant production device  170  calculates or receives a tool path which instructs the implant production device on where to grind or cut away material from the titanium block, based upon the three-dimensional data generated at the imaging system  140 .  
      The imaging system  140 , in response to user operation of the user interface  160 , selectively adjusts the shape of the three-dimensional image  110  such that the dental implant  130  produced at the implant production device  170  is able to be seated directly back into a fresh socket of the jawbone. The user adjusts the three-dimensional data associated with image  110  displayed on the display device  150  in order for the implant production device  170  to form an implant  130  that will be optimal for bone integration in accordance with the implant site. For instance, if the root portion of the extracted tooth is curved, the implant may need to be modified (via adjustment to the image data obtained) such that the implant will be able to be tapped into place in a controlled manner, fitted and seated in the corresponding fresh socket of the jawbone.  
      In another example, the imaging system  140 , in response to user input at the user interface  160 , adjusts the data associated with the shape of the tooth image  110  such that the implant production device  170  forms the dental implant  130  with a wide portion  132  proximate a top end  134  which opposes a root portion  136  of the implant. The wide portion  132  is positioned proximate the opening of the socket upon implant insertion so as to reduce the chance of soft tissue interfering with the healing of the bone below the gingiva. The material (e.g. a titanium blank), inserted into the implant production device  170  for milling, may selectively have the facility to allow an abutment to be screwed into the dental implant. Alternatively, implant production device  170  may be programmed to form an abutment  138  extending from the wide portion  132  at the top end  134  of the implant. The abutment  138  may be automatically generated by the implant production device  170  or based upon user input to modify the image at display device  150  to include the tooth abutment. The abutment  138  may have a width ranging from approximately 50% to 70% of the width of the wide portion  132  of the implant  130 . The height of the abutment  138  may be determined according to the space required to place a crown.  
      The implant production device  170  may produce a dental implant  130 A, Fig., having an abutment portion  137  that is formed as an integral part of the dental implant such that the abutment portion  137  is positioned at an occlusal part  139  of the dental implant atop of the root portion  136 . The occlusal part is generally the portion of the implant which supports a dental prosthesis, such as a dental crown, located proximate to biting or chewing surfaces. The imaging system  140  scans a tooth  120  (or other dental item) and generates a displayed image  110  of the tooth. Data associated with the three-dimensional image  110  is modified to design an abutment portion  115  ( FIG. 13 ) of the three-dimensional image of the tooth or other dental item being imaged. The design of the abutment image  115  may be accomplished by user interaction with interface  160 ,  FIG. 1 , as described above, to modify the three-dimensional data relating to the displayed image  110 . Alternatively, the abutment portion design may be automatically generated based on predetermined parameters set at the imaging system  140  to modify the three-dimensional image data in response to the imaging of the particular dental item  120 . The dental abutment image may selectively have a design which mimics a shape and contour of a corresponding ideal crown preparation of the dental item being imaged. The design of the abutment image, in some instances, may also be selected to have a corresponding size and thickness that is smaller than the size and thickness of an ideal dental crown for the tooth being imaged, without undercuts. The abutment portion  137  of the dental implant  130 A will be produced at implant production device  170  to have a size and shape that corresponds to the design for the abutment portion of the three-dimensional image  110  in accordance with the modified three-dimensional image data. The machined dental implant  130 A, for example, may have an abutment portion  137  that is smaller than a corresponding non-root portion or crown of the imaged tooth  120  in order to permit the placement of a prosthetic dental crown with an optimum thickness according to manufacturer specifications for the crown material.  
      As described herein, a three-dimensional digitizer of the laser digitizer imaging system  140  captures data, by imaging reflected light from the imaged tooth  120 , and the computer controlled imaging system  140  computes three-dimensional data which is associated with the surface of the imaged tooth. The user, via user interface  160  coupled with the computer controlled imaging system  140 , is able to manipulate and modify the three-dimensional data, stored in the imaging system, that is associated with the imaged tooth. A three-dimensional image  110  of the tooth  120 , or portions thereof, is displayed for viewing by the user at display device  150  coupled with the imaging system and the user interface.  
      The occlusal third or some portion of the dental implant  130 , for example, may be made slightly larger than the corresponding portion of the imaged tooth  120  to provide enhanced stability of the implant inserted into the tooth socket at the extraction site. Any excessive length or curve at the bottom portion of the tooth may also be truncated when forming the dental implant  130 . The surface texture for the dental implant may also be specified by the user. The user may select a surface quality, for example, through interaction with a slider which offers the choice of a range from “smooth” to “rough”, or a numerical range which is representative of a final finish quality on the final milled implant. The choice of cutting tool and the tool-path parameters that may be selected by the user may also result in different surface textures. The user may also design a prosthesis such as a dental crown to be attached to the dental implant preferably via an abutment integral to the occlusal portion of the implant. Once the particular shape and size of the dental crown are designed by the user through interaction at user interface  160 , a temporary crown formed from a composite block or similar suitable material (inserted at production device  170 ) may be milled for engagement with a formed dental implant.  
      Tool path programming at the implant production device  170  (e.g. a computer controlled milling machine) computes a tool path which is dependent on the particular configuration of the implant production device. Tool path data may alternatively be computed at the computer controlled imaging system  140  upon generation or modification of the three-dimensional image data. The tool path will depend, for example, on the relative position of the single or multiple spindles with respect to motion axes (e.g. translation or rotational axes) of the implant production device. The tool path will also depend on the size and shape of the tooth (corresponding to the implant to be produced) as well as the geometry of the three-dimensional designed implant to be milled.  
      Referring to  FIG. 13 , the steps of imaging an extracted tooth or dental impression, modifying the image obtained, producing a dental implant, and inserting the implant into a fresh socket created upon removal of the tooth are illustrated. Initially the tooth  120  (or impression) is scanned by the lazer digitizer imaging system  140  which creates a three-dimensional image  110  of the tooth for display at the display device  150 . Through selective input at the user interface  160 , the user may modify data associated with the size or shape of the displayed three-dimensional image  110  to design a dental implant in an effort to optimize the implant procedure based on the characteristics of the implant site. For example, the user may modify the image to remove the crown portion  112  (or other non-root portion) of the tooth imaged  110  and to form a relatively flat and wide portion  114  proximate the occlusal end of the root portion  116  imaged to establish a generally “T-shaped” lid of the dental implant to be produced. Alternatively, a separate disc shaped lid may be attached on the occlusal portion of the implant to prevent the epithelium from growing into the extraction site and the lid is removed when placement of an abutment or final crown is made.  
      Once image modifications are made, if any, the imaging system  140  transmits information, such as three-dimensional image data or tool-path data, associated with the selected image to the implant production device  170  which prepares a dental implant  130  based on the information received from the imaging system. After the dental implant  130  is produced it may be inserted into the mouth of the patient by controlled tapping or screwing the implant into the socket  172  of the jawbone  174  previously housing the tooth  120 . The dental implant  130  formed has a size and shape that mimics portions of the extracted tooth so that it may immediately be firmly inserted into a fresh socket  172  and allow the bone  174  to grow into and integrate with the implant.  
       FIG. 14  provides an illustrated example of imaging a dental item such as a tooth or dental impression having a curved root portion and producing a dental implant. As seen in  FIG. 14 , root  122  of tooth  120  has a curved portion  123 . The tooth  120  is scanned by imaging system  140  to create a three-dimensional image of the tooth displayed at display device  150 . Initially, the image  110  displayed at display device  150  may include image display of a corresponding crown portion  112  and curved root portion image  125 . The user interacts with user interface  160  (and imaging system  140 ) to modify the three-dimensional data associated with the displayed image to create a modified image  117 . The modified image  117  may have the imaged crown portion  112  and the imaged curved root portion removed to design an implant meeting user desired specifications. The modified image  117  may selectively include an abutment portion  115  extending proximate an end of the root portion image. The imaging system  140  transmits three-dimensional data, or alternatively tool-path data, associated with the modified image  117  to the implant production device  170  which prepares a dental implant  130  based on the received data associated with the modified image. Once produced, the implant  130  is inserted into the socket  172  that previously held the tooth and the bone  174  will grow into the void  175  located proximate a root end of the implant that is placed into the socket.  
      In some instances the root portion  122  of the tooth  120 ,  FIG. 14 , is at an angle relative to the non-root portion  119  (e.g. crown portion or occlusal part) of the tooth. In such cases, the angle between the root portion  119  and the non-root portion  122  of the tooth  120  is determined by the imaging system  140  or alternatively, through manual observation by the user. The tooth  120  (or other dental item) is imaged by imaging system  140  and the three-dimensional image of the dental item is displayed at display device  160 . The shape of the three-dimensional image  110  is selectively modified to create an abutment portion  115  extending from a root portion  117  of the modified three-dimensional image. Through interaction with user interface  160  coupled with imaging system  140 , the user is able to selectively position the abutment portion  115  of the displayed three-dimensional image at an angle relative to the root portion  117  of the three-dimensional image such that the positioned angle will mimic the angle between the root portion  122  and the non-root portion  119  of the tooth  120  that is being imaged. The implant production device  170  will produce an implant having an abutment positioned at an angle relative to a root portion of the implant in accordance with the modified three-dimensional image. Thus, when the dental implant  130  is placed into the socket  172  previously retaining the tooth  120 , the abutment  138  of the implant will be positioned at a desirable angle to accept a dental crown prosthesis. The produced dental implant  130  may also have markings on its surface to assist the user in orienting the dental implant for insertion into the socket. In some instances, employment of an intra-oral laser digitizer imaging system ( FIGS. 7, 8 ) may be used to image the tooth  120  (in vivo) as well as neighboring and opposing teeth to determine a desirable angle to be established between the abutment and root portion of the modified image and the corresponding dental implant.  
       FIGS. 2   a  and  2   b  illustrate an example of the imaging system which in this example is a laser digitizer imaging system  140 A configured to generate a three-dimensional (3D) image of a tooth  220 , dental impression or other dental items. The laser digitizer imaging system  140 A includes a laser light source  202 , an optical scanner  222 , a flat-field lens  228 , that may be known as an F-Theta lens, an image capture instrument  230 , and a processor  236 . The processor  236 , for example, may include programming to display the imaged tooth  110  and modify the data used to generate the three-dimensional image. In one example, processor  236  of computer controlled imaging system  140  may also be programmed to generate tool-path data converted from the three-dimensional image data and to transmit the tool-path parameters to the implant production device  170 . The laser digitizer imaging system  140 A may also include a positioner (not shown) for securing and positioning the tooth to be imaged. The laser digitizer imaging system  140  may also include a variable beam expander  242  optically positioned between the laser source and the scanner  222 . For further details on the laser digitizer imaging system, reference can be made to U.S. patent application Ser. No. 10/749,579 filed Dec. 30, 2003 for “Laser Digitizer System for Dental Applications” of Quadling et al. which is incorporated in its entirety herein by reference.  
      The laser light source  202  generates a laser beam that is projected and scanned across a tooth to be imaged by the scanner  222  and the F-Theta lens  228 . The scanned light is reflected from the tooth  220  and detected by the image capture instrument  230 , which generates a signal representative of the detected light.  
      The laser light source  202  may include collimating optics (not shown) that produce a collimated light beam  238  having parallel rays of laser light. This collimated light beam  238  is projected towards a two-axis optical scanner  222 .  
      The laser light source  202  may include a laser diode or LED configured to generate a laser light beam that may have an elliptical-shaped beam. The collimating optics may be configured to circularize the elliptical beam and to generate a circular spot. The circular spot may be used to scan a uniform line across the surface of the tooth  220 . The laser diode may be any commercially available laser diode configured to emit a laser light beam, such as a 10 mW laser diode from Blue Sky Research having a 4 mm beam size at a 635 nm wavelength (part number MNI-0635-1 01C40W).  
      The laser light source  202  also may be configured to modulate laser light. The laser light source  202  also may be coupled to a modulator that adjusts or interrupts light flow from the source at high modulation or switching rate such as 20 MHz rate. By switching the laser light source  202 , the coherence of the laser light emitted from the laser light source  202  may be reduced, thereby reducing speckle.  
      The scanner  222  redirects or scans the collimated light beam  238  to form a scanned light beam  240  having a position that may vary over time. The scanned beam  240  is directed by the scanner  222  to the F-theta lens  228 . The scanner  222  redirects the collimated light beam across two axes where each axis is substantially perpendicular to the axis of the collimated light beam  238 . The scanned light beam  240  may be scanned in at least two or more axes.  
      The scanner  222  includes a first reflector  224  and a second reflector  226 . The first and second reflectors  224 ,  226  may comprise optical mirrors or surfaces capable of reflecting undiffused light to form an image. Each reflector  224 ,  226  may be rotatably coupled with a respective motor  244 ,  246 . Each motor  244 ,  246  may comprise a galvo drive motor, or the like, that controls a rotational movement of the respective reflector  244 ,  226  to effect the scanning of the collimated light beam  238 .  
      The first and second reflectors  224 ,  226  may have essentially perpendicular axes, and may be essentially orthogonal with respect to each other. The reflectors  224 ,  226  also may be positioned at an arbitrary angle relative to each other. Additional reflectors may also be included. The reflectors  224 ,  226  may be positioned orthogonally so that the collimated laser beam  238  incident on the reflectors may be scanned or redirected in at least two axes. The first reflector  224  scans the beam along one axis, such as an x-axis. The second reflector  226  may be positioned so that the beam along the x-axis incident upon the second reflector  226  may be scanned along an orthogonal direction to the x-axis, such as a y-axis. For example, the first and second reflectors  224 ,  226  may be positioned orthogonal with respect to each other so that the first reflector scans the beam along the x-axis and the second reflector  226  scans the beam along an orthogonal direction to the x-axis, such as a y-axis.  
      The first reflector  224  also may comprise a spinning polygon mirror such that the rotatable second reflector  226  and the spinning polygon reflector  224  together also are configured to scan the laser beam in two axes. The spinning polygon mirror  224  may scan the collimated light beam  238  along an x-axis and the rotatable mirror  226  may scan the collimated light beam along a y-axis. Each axis, the x-axis and y-axis, may be substantially orthogonal with one another, thereby generating a scanned light beam  240  from the collimated beam  238  where the scanned light beam  240  is scanned along two substantially orthogonal axes.  
      The scanner  222  also may include a programmable position controller. The position controller may be a component of the scanner  222  or may be incorporated with the processor  236 . By incorporating the position controller with the scanner  232 , computing resources of the processor  236  are available for other functions such as processing the image data or for more advanced processing. The position controller may comprise a commercially available controller such as the GSI Lumonics SC2000 Scanner Motion Controller which controls the scanning of the two reflectors. The controller may be configured to control the movement of the reflectors  224 ,  226  by controlling the motors  244 ,  246 . The controller controls the movement of the reflectors  224 ,  226  so that the collimated laser beam  238  is redirected to provide to a desired scan sequence. A coordinate system for the scanner  222  is referred to as X′Y′Z′.  
      The scanned beam  240  is incident to the F-Theta lens  228 . The F-theta lens  228  focuses the scanned beam  240  to a point or dot. The tooth  220  to be imaged is positioned within a field of view of F-Theta lens and the image capture instrument  230 . The F-theta lens  228  has an optical axis at an angle  0  with respect to an optical axis of the image capture instrument  230  so that when the focused dot is scanned across the surface of the tooth  220  the light is reflected towards the image capture instrument at angle θ. The scanner  222  moves the scanned beam  240  so that the focus point of the laser dot from the F-Theta leans  228  traverses through a pattern across the surface of the tooth  220 . The F-Theta lens  228  may be any commercially available lens such as part number 4401-206-000-20 from Linos, having a 160 mm focal length, a 140 mm diagonal scanning length, ±25 degree scanning angle and 633 nm working wavelength.  
      The image capture instrument  230  may be configured and/or positioned to have a field of view that includes the focused laser dot projected on the tooth  220 . The image capture instrument  230  detects the laser dot as it is scanned across the surface of the tooth  220 . The image capture instrument  230  may be sensitive to the light reflected from the tooth  220 . Based on a light detected from the tooth  220 , the image capture instrument generates an electrical signal representative of the surface characteristics (e.g., the contours, shape, arrangement, composition, etc.) of the tooth  220 .  
      The image capture instrument  230  may include an imaging lens  232  and an image sensor  234 . The imaging lens  232  is configured to focus the light reflected from the tooth  220  towards the image sensor  234 . The imaging lens  232  may be a telecentric lens configured to minimize perspective errors. The imaging lens  232  may have an internal stop configured to image mostly parallel rays incident at a lens aperture to reduce or eliminate an effect of magnification and perspective correction. The imaging lens  232  may be any commercially available lens configured to minimize perspective distortions such that a lateral measurement on the image of a tooth does not depend on the distance of the tooth from the lens such as the China Daheng Corp. combination with front lens number GCO-2305 (50 mm diameter) and the back lens number GCO-2305 (8 mm diameter) where the back lens corresponds to the imaging capture instrument sensor size.  
      The image sensor  234  captures an image of the scanned surface of the object. The image sensor  234  may be a photo-sensitive or light sensitive device or electronic circuit capable of generating signal representative of intensity of a light detected. The image sensor  234  may include an array of photodetectors. The array of photodetectors may be a charge coupled device (“CCD”) or a CMOS imaging device, or other array of light sensitive sensors capable of generating an electronic signal representative of a detected intensity of the light. The image sensor  234  may comprise a commercially available CCD or CMOS high resolution video camera having imaging optics, with exposure, gain and shutter control, such as Model SI-3170-CL from Silicon Imaging of Troy, N.Y. The image sensor  234  also may include a high bandwidth link to a framegrabber device, such as the PIXCI CL1 capture and control computer board from Epix, Inc.  
      Each photodetector of the array generates an electric signal based on an intensity of the light incident or detected by the photodetector. In particular, when light is incident to the photodetector, the photodetector generates an electrical signal corresponding to the intensity of the light. The array of photodetectors includes multiple photodetectors arranged so that each photodetector represents a picture element, or pixel of a captured image. Each pixel may have a discrete position within the array. The image capture instrument  230  may have a local coordinate system, XY such that each pixel of the scanned pattern corresponds to a unique coordinate (x,y). The array may be arranged according to columns and rows of pixels or any other known arrangement. By virtue of position of the pixel in the array, a position in the image plane may be determined. The image capturing instrument  230  thereby converts the intensity sensed by each pixel in the image plane into electric signals that represent the image intensity and distribution in an image plane.  
      The CMOS image sensor may be configured to have an array of light sensitive pixels. Each pixel minimizes any blooming effect such that a signal received by a pixel does not bleed into adjacent pixels when the intensity of the light is too high.  
      The scanner  222  may be configured to scan the laser beam  240  across the surface of the object  220  via the F-Theta lens  228  in many desired patterns. The pattern may be selected to cover a sufficient portion of the surface of the tooth  220  during a single exposure period. The pattern may also comprise one or more curves or any known pattern from which the characteristics, elevations and configurations of the surface of the tooth  220  may be obtained.  
      During an exposure period, an image of a portion of the surface of the object is captured. The beam  240  scan the tooth  220  via the scanner  222  and the F-Theta lens  228  in a selected pattern, allowing the imaging sensor  230  to detect the light reflected from tooth  220 . The image sensor  230  generates data representative of the surface characteristics, contours, elevations and configurations of the scanned portion or captured image. The data representation may be stored in an internal or external device such as a memory.  
      During a subsequent scan period, the beam  240  is scanned in a pattern across an adjacent portion of the tooth  220  and an image of the adjacent portion is captured. The scanned beam  240  may scan a different area of the surface of the tooth  220  during subsequent exposure periods. After a several exposure periods in which the beam  240  is scanned across the various portions of the tooth  220  and images of those scanned portions captured, a substantial portion of the tooth may be captured.  
      The processor  236  is coupled to the image capture instrument  230  and configured to receive the signals generated by the image capture instrument  236  that represent images of the scanned pattern on the tooth  220 .  
      The processor  236  also may be coupled to the laser light source and control selected or programmed applications of the laser light. The processor  236  also  10  may be coupled with the scanner  222  and programmed to control the scanning of the collimated light  238 .  
       FIG. 3  illustrates an example of a scanned pattern of light  348  as viewed from a substantially flat surface. The scanned pattern  348  may include multiple curves  350 - 355  that are generated by the scanner  222 . A portion of the curves  350 - 351  may be essentially parallel to each other. The curves  350 - 355  also may represent or include a connected series of points or curvilinear segments where a tangent vector n at any single point or segment obeys the following rule: 
 | n·R|≠ 0   (1)  
 where R is a triangulation axis that is substantially parallel to Y and Y′ and passes through an intersection of an axial ray from the image capture instrument  230  and an axial ray from the optical scanner  222 . Accordingly, the angle between the tangent n at any point or segment of the curve and the triangulation axis R is not 90 degrees. Each curve  350 - 355  also may have a cross-sectional intensity characterized by a function that may have a sinusoidal variation, a Gaussian profile, or any other known function for cross-sectional intensity. In an embodiment, a minimum angle between a valid ray between the scanner  222  relative to a valid axial ray of the image sensor  234  is non-zero. 
 
      The image capture instrument  230  may be characterized by a local coordinate system XYZ, where the X and Y coordinates may be defined by the image capture instrument  230 . A value for the Z coordinate may be based on the distance d 1  and d 2  so that d 1 ≦z≦d 2 . A point from a projected curve incident to a plane perpendicular to Z will appear to be displaced in the X direction by Δx. Based on a triangulation angle, the following condition may exist:  
               Δ   ⁢           ⁢   z     =       Δ   ⁢           ⁢   x       Tan   ⁢           ⁢   θ               (   2   )             
 
      For a given curve (e.g. curve  350 ) in the projection pattern there may be unique relations θ(y), z base (y) and X base (Y). The relations θ(y), z base (Y) and X base (y) relations may be determined through calibration. The calibration may be performed for example by observing the curve  350  as projected on a plane surface. The plane surface may be perpendicular to the image capture instrument  230  at two or more distances d along the Z axis from the image capture instrument  230 . For each y value along the curve  350 , using at least two such curves with known z values of z 1 , and z 2 , where z 1 &lt;z 2 , Δz may be computed as Δz=z 2 −z 1 . A value Δx may be observed using the image capture instrument  230 . Using equation (2), θ(y) may be computed. The corresponding value z base (Y) may be set equal to z 1 . The corresponding value x base (y) may be equal to an x value at the point y on the curve corresponding to z 1 . Additional curves may be used to improve accuracy of through averaging or interpolation.  
       FIG. 4  illustrates the scanned pattern of light  448  incident to the object  420  to be imaged.  FIG. 5  illustrates the light pattern reflected from the object  420  as incident to the image sensor  534 . For the observed projected curves  550 - 555  on the tooth, each curve corresponds to one of the curves  450 - 455  shown in  FIG. 4  and a corresponding one of the curves  350 - 355  shown  FIG. 3 . Accordingly, for each curve  550 - 555 , the corresponding relations θ(y), z base (y) and x base (y) may be selected that were precomputed during a calibration. For each point (X observed ,Y observed ) on each curve  550 - 555 , 
 Δ x=   observed   −x   base ( y   observed )   (3)  
 Equation (2) may be used to determine Δz using θ(y observed ), and consequently 
   z   observed   =Δz+z   base ( y   observed )   (4)  
 The collection of points (x observed , y observed , z observed ) obtained, form a 3D image of the tooth  420 . 
 
      A maximum displacement for a curve may be determined by: 
 
Δ x =( d   1   −d   2 )Tan θ  (5) 
 
 A maximum number of n max  of simultaneously distinguishable curves  350  may be determined according to n max =X max /Δx or equivalently  
               n   max     =       X   max         (       d   1     -     d   2       )     ⁢   Tan   ⁢           ⁢     θ   max                 (   6   )             
 
 The number n max  increases with a decreasing depth of field d 1 -d 2  and increases with a smaller θ max . The accuracy of the determination also may decrease with a smaller θ max  values. 
 
       FIG. 6  illustrates an example of an object positioner  660 . The positioner  660  is configured to secure and position a tooth  620 , impression or other dental item to be imaged in the field of view of the scanned laser beam  240  and the image capture instrument  230 . The positioner  660  may include two or more rotary axes to provide for rotation of the tooth  620 . The tooth  620  may be rotated with respect to the coordinate system XYZ of the image capture instrument  230 . The positioner  660  also may include a linear axis to linearly adjust the tooth  620  to a focal point for the scanning system and image capture unit  230  system.  
      The positioner  660  also may include a platform  664  and a spring loaded clamp  662 . The spring-loaded  662  clamp may be configured to securely hold an extracted tooth  620 . The clamp  662  also may have magnets (not shown) so that it may be rigidly secured through magnetic attraction to the positioning platform  664 . This tooth  620  may be quickly positioned with the laser imaging system by securing it into the clamp  662  and placing the clamp onto the platform  664 . The tooth  620  may be moved or adjusted with respect to the platform  664  to a desired the position appropriate for digitizing the region of interest.  
      Referring now to  FIG. 7 , an alternative embodiment of a laser digitizer imaging system  140 B is shown.  FIG. 7  illustrates an example of an intra-oral laser digitizer imaging system  140 B. The intra-oral digitizer imaging system  140 B generates a three-dimensional image of an object  720  such as a tooth, dental impression or other dental item. The intra-oral laser digitizer imaging system  140 B generates a laser pattern that may be projected on or towards tooth, a dental item, dentition, or prepared dentition in an oral cavity (in vivo). The intra-oral digitizer system  140 B may remotely generate the laser pattern and relay the pattern towards the dental item or items in vivo. The laser pattern may be relayed through relay optics such as prisms, lenses, relay rods, fiber optic cable, fiber optic bundles, or the like. The intra-oral laser digitizer system  140 B also may detect or capture light reflected from the tooth or other dental item in vivo. The intra-oral laser digitizer imaging system  140 B, or a portion thereof, may be inserted in the oral cavity to project the laser pattern and to detect the reflected laser pattern from the tooth, dental item or items in the oral cavity. The captured light may be used to generate data representative of the three-dimensional image of the dentition. The data is used to display the three-dimensional image  110 ,  FIG. 1 . The data associated with the three-dimensional image is used to form a model of the tooth for use as a dental implant using known techniques such as milling techniques. For further details on the intra-oral laser digitizer or imaging system, reference can be made to U.S. patent application Ser. No. 10/804,694 filed Mar. 19, 2004 for “Laser Digitizer System for Dental Applications” of Quadling et al. which is incorporated in its entirety herein by reference.  
      The laser digitizer imaging system  140 B,  FIG. 7 , includes a laser light source  701 , a first scanner  702  (x scanner), a second scanner  703  (y scanner), a lens assembly  704 , a first reflecting prism  713 , a first optics relay  705 , a second reflecting prism  707 , a third reflecting prism  706 , a second optics relay  709 , imaging optics assembly  710 , imaging sensor  711 , and an electronic circuit  712 . The intra-oral laser digitizer imaging system  140 B is also coupled to processor  719  which is selectively programmed to display and modify three-dimensional image data and may also be programmed to generate tool-path parameter data for use at implant production device as previously described.  
      The laser light source  701  may include collimating optics (not shown) that generate a laser beam of light  722  from the light source  701 . The collimated light beam  722  is characterized by parallel rays of laser light. The laser beam  722  is projected to the first scanner  102 .  
      The laser light source  701  may include a laser diode or LED that generates a laser light beam having an elliptical-shaped cross-section. The collimating optics may be configured to circularize the elliptical beam and to generate a circular spot. The circular spot may be used to scan a uniform line across the surface of the object  720  (e.g. tooth in vivo). The laser diode may be any commercially available laser diode configured to emit a laser light beam, such as the Blue Sky Research Mini-Laser 30 MWatt laser with 0.6 mm collimated beam, model number Mini-635D3D01-0.  
      The laser light source  701  also may modulate the laser light beam. The laser light source  701  may be coupled to a modulator that adjusts or interrupts light flow from the source at high modulation or switching rate. The modulation may be in the range of substantially 1 kHz to substantially 20 MHz. A scan pattern may be generated on the object, by modulating the laser light source  701 .  
      The first scanner  702  includes an x-scanner mirror having a substantially flat reflecting surface. The reflecting surface of the x-scanner mirror, may be rectangular-shaped having dimensions approximately 1.5 mm by approximately 0.75 mm. The laser beam  722  from the light source  701  may have a width no greater than the smallest dimension of the first scanner  702 . For example, the width of the laser beam may be approximately 0.6 mm. The beam of light  722  from the laser light source  701  is incident upon the reflecting surface of the first scanner  702 .  
      The second scanner  703  includes a y-scanner mirror having a substantially flat reflecting surface. The reflecting surface of the y-scanner mirror, may be rectangular-shaped having dimensions approximately 1.5 mm by approximately 0.75 mm. The reflecting surfaces of the x-scanner and the y-scanner may be mirrors or the like.  
       FIG. 8  illustrates an alternative embodiment of an intra-oral laser digitizer imaging system configured as an optical coherence tomography (“OCT”) or confocal sensor. Optical coherence tomography may be used for performing in vivo imaging of dental items such as a root portion of a tooth or dental impression. The laser digitizer system of  FIG. 8  includes a fiber-coupled laser  811 . The laser source  811  may be a low coherence light source coupled to a fiber optic cable  810 , coupler  809  and detector  801 . The coupler, an optical delay line  805  and reflector  804  return delayed light to the coupler  809 . The coupler  809  splits the light from the light source into two paths. The first path leads to the imaging optics  806 , which focuses the beam onto a scanner  807 , which steers the light to the surface of the object. The second path of light from the light source  811  via the coupler  809  is coupled to the optical delay line  805  and to the reflector  804 . This second path of light is of a controlled and known path length, as configured by the parameters of the optical delay line  805 . This second path of light is the reference path.  
      Light is reflected from the surface of the object (e.g. tooth) and returned via the scanner  807  and combined by the coupler  809  with the reference path light from the optical delay line  805 . This combined light is coupled to an imaging detector system  801  and imaging optics  802  via a fiber optic cable  803 . By utilizing a low coherence light source and varying the reference path by a known variation, the laser digitizer provides an Optical Coherence Tomography (“OCT”) sensor or a Low Coherence Reflectometry sensor. The focusing optics  806  may be placed on a positioning device  808  in order to alter the focusing position of the laser beam and to operate as a confocal senor. For further details on the laser digitizer imaging system utilizing optical coherence tomography, reference can be made to U.S. patent application Ser. No. 10/840,480 filed May 5, 2004 for “Optical Coherence Tomography Imaging” of Quadling et al. which is incorporated in its entirety herein by reference.  
      Referring now to  FIG. 9 , one example of an implant production device  170  is shown characterized as a milling machine having a sturdy frame  902  to minimize vibration. The implant production device  170  has spindles that rotate milling bits located on a common rail, giving the device the ability to move cutting tools attached to the spindles in the x-axis. A blank  905 , such as a titanium block, is positioned within and is releasably attached to a mandrel  960 . The mandrel  960  is secured to a subassembly  940  ( FIG. 12 ) having a y-axis carriage  942  and a z-axis carriage  943  that allows motion in the y-axis and the z-axis. The block  905  to be milled is held by the mandrel that engages a frame within a work area that is easily accessible to the user (such as a dentist or other dental technician). The implant production device  170 ,  FIG. 9 , includes a central processing unit (CPU) and memory for storing data received from the imaging system  140  on the contour of the implant or other dental item to be produced. The central processing unit at implant production device  170  may receive tool-path parameter data received from the imaging system  140  (formed from the three-dimensional image data also generated at imaging system). The tool-path parameter data provides instructions to the implant production device  170  on how to perform to produce a dental implant. Alternatively, the CPU at implant production device  170  may receive three-dimensional image data from the imaging system  140  and generate the tool-path parameter data associated with the displayed image itself at the production device.  
      As described above, a laser digitizer imaging system such as an intra-oral laser digitizer system  140 B,  FIG. 7 , may be used to measure the dimensions of the tooth  120 ,  FIG. 1 , as well as the adjacent and opposed teeth. Software within the laser digitizer system constructs an outer contour that meshes with the adjacent and opposing teeth. The design may be modified and is approved by the user and then conveyed to the implant production device  170 .  
       FIG. 9  provides a perspective view of the implant production device  170 . A blank  905 , (comprised of titanium or other biocompatible material) is held within a work area that is accessible through door  904 . The blank  905 , of titanium or other biocompatible material, that is inserted into the implant production device  170  may, for example, have a shape that is similar to the shape of the dental implant  130  to be produced. By selecting a blank  905  to be machined that is similar in shape and size (but preferably slightly larger) to the final design of the dental implant to be produced, machining time will be reduced as less material will be needed to be removed from the similarly shaped blank. The x-axis carriage  910  is used to move tools back and forth into engagement with the blank  905 . The x-axis carriage  910  includes a first and second frame that both slide on rails on subframe  912 . Subassembly  940  ( FIG. 12 ) having y-axis carriage  942  and z-axis carriage  943  is used to control the y-axis and z-axis movement of the mandrel  960  and blank  905 . The CPU, memory and other electronics for implant production device  170  are located in compartment  907 ,  FIG. 9 . These can selectively be controlled, or activity displayed on display  906  of implant production device  170 . For further details on the implant production device, reference can be made to U.S. patent application Ser. No. 10/917,069 filed Aug. 12, 2004 for “Improved Milling Machine” which is incorporated in its entirety by reference.  
       FIG. 10  is an isolated view of the x-axis carriage  910 . It includes a first frame  914  and a second frame  916 . In one embodiment, these frames are formed from a single block of metal. A first and second spindle  918 ,  920  are coupled to these frames  914 ,  916 . The frames  914 ,  916  move on a single pair of rails  922  to ensure alignment. Each frame is coupled to a first and second spindle, wherein each spindle has a central axis. The central axis of each spindle is aligned. Tools  928  and  930  are accepted into the spindles along this axis. The spindles  918 ,  920  rotate the tools  928 ,  930  so that a cutting surface on the tool can carve away material from the blank as desired. Air streams emit from the spindle ports  926 ,  FIG. 11 , to cool the spindles and motors during milling. Motors  924 ,  FIG. 10 , are used to supply the power to move the frames along the rails and to rotate the tools within the spindles. Tools  928  and  930  held by first and second spindles  918 ,  920 , respectively, are manipulated on the x-axis carriage to mill titanium blank  905 . The x-axis carriage  910  advances spindles  918 ,  920  such that the grinding tools  928 ,  930  engage and make contact with the titanium blank  905 . The titanium blank  905  seated at the mandrel  960  ( FIG. 12 ) is positioned in the y-axis and z-axis by use of the y-axis carriage  942  and z-axis carriage  943 .  
      The outer contour of the imaged tooth  120 ,  FIG. 1 , is reproduced at the implant production device  170 . This requires an accurate understanding of the location of the tip of the tools and the x, y, z coordinates of the blank  905 . Thus the shape and length of the mandrel  960 ,  FIG. 12 , holding the blank  905  must be precise. Motors  924  are used to move the x-axis carriage  910  shown in  FIG. 10 . This same level of precision is reproduced for the y and z axes. However, rather than move spindles, the mandrel  960  holding blank  905  is moved in the y and z axes by the subassembly  940  having y-axis carriage  942  and z-axis carriage  943  shown in  FIG. 12 . In  FIG. 12 , the y-axis  942  is controlled by moving y-axis carriage along rails oriented in the “y” direction. Movement along the z-axis is accomplished by z-axis carriage  943  powered for movement by motor  945 . The y-axis carriage  942  includes the frame for engaging the mandrel  960  and automatic tool changer  950 . This view also illustrates the location of the mandrel  960  and blank  905  to be milled on the y-axis carriage  942 . Movement of the y-axis carriage  942  is powered by a y-axis motor (not shown). A cam  962  is used to secure the mandrel in place. The tool changer  950  can carry several additional tools  928 ,  930  for placement into the spindles. The tool changer  950  also includes at least one open port  954  for accepting the tool in the spindle.  
       FIG. 11  provides a more detailed view of the spindle  920  and the tool  930 . The tool  930 , shown in  FIG. 11 , includes a distal end that is engaged within the spindle. Flanges  931 ,  FIG. 11 , serve the purpose of assisting with the registration of the tool and the blank. In other words, even though the exact length of the tool  930  is known, the x, y, z coordinates of its tip  932  is also known. When the tool  930  is engaged into the spindle  920 , the flange  931  acts as a travel limit and thus defines the distance between the tip and the spindle. Thus, when the spindle  920  moves along the x-axis, the position of the tip  932  of the tool  930  will be known. In addition to knowing the exact x, y, and z coordinates of the tool tips, the position of the blank  905  is also known. This requires that the mandrel  960  and blank  905  be consistently placed into the implant production device. The mandrel  960  and blank  905  engage a mandrel socket that in turn engages the y-axis carriage  942 ,  FIG. 12 , to consistently position the mandrel for milling operation.  
      Each tool  928 ,  930  is indirectly rigidly attached to the x-axis carriage  910  aligned to move along the x-plane, which are moved by a motors  924  as shown in  10 . In addition, the mandrel  960 ,  FIG. 12 , is rigidly attached to subassembly  940  which is moved in the y and z directions via separate motors on each of the y and z assemblies. In this example, a total of four motors move a total of four carriages. These four separate motion directions may be referred to as “X-left”, “X-right”, “Y” and “Z”. The origin of the coordinate system in the milling machine may be defined in any way. One choice for the origin of the coordinate system for each of the “X-left”, “X-right”, “Y” and “Z” axes may be located at the end of the mandrel, in the center of the mandrel. Exact motions along each of the axes may be chosen in a coordinated motion by sending coordinated information to each of the motors simultaneously. Such coordinated motion may include position, speed, acceleration, jerk and time information, which instructs each motor to be at a given location with a given speed and/or acceleration and/or jerk value at a particular point in time. This may be done, for example, by an electronic motion control board (located at compartment  907 ), which is attached via cables or wires to each of the motors. The motion control board is attached in compartment  907 ,  FIG. 9 , to the central processing unit in the milling machine, which instructs the motors via the motion control board to implement a coordinated motion profile. In this way, the tool tips  932  may be instructed to trace a specified and precise contour in a coordinated fashion, while the mandrel  960  traces a specified and precise contour coordinated with the tips  932  of tools  928 ,  930 .  
      The relative motion between the tool tips  932  and the block of material  905  attached to the mandrel  960  is then controlled very precisely, and may correspond to the three-dimensional shape of the implant to be machined. The computed trajectory of the tool tips  932  relative to the blank  905  on the mandrel  960  will take into account the shape of the tools  928 ,  930 , the wear or condition of the tools, the size of the tools, and other aspects such as the level of accuracy required in the final machined implant, or the surface quality or texture of the final machined implant.  
      Referring now to  FIG. 15 , one example of the steps of producing a dental implant from a dental item such as a tooth or dental impression at the dental implant production system  100  is provided. In step  1000 , a dental item such as an intact tooth, extracted tooth or a dental impression of the socket previously retaining an extracted tooth is scanned and digitized using the lazer digitizer imaging system  140 . In step  1002 , the imaging system  140  acquires multiple three-dimensional data patches of the portions of the tooth (e.g. root portions) or the dental impression being scanned. The raw data obtained by the imaging system  140  digitizing the dental item is transferred to a processor of the imaging system coupled to the display device  150  to be processed in step  1004 . The processing may be accomplished at the imaging system  140  or alternatively performed at a display device  150  having processing capabilities. In step  1006 , the processor processes the raw data from each scan performed by the imaging system  140  and separates the raw data from each scan into three-dimensional patches.  
      In step  1008 , alignment and merging of the multiple three-dimensional data patches into a single point cloud is performed by the processor of imaging system  140  coupled with the display device  150 . In step  1010 , a closed polygon mesh is formed from the point cloud and is displayed at the display device  150 . Production of polygon meshes from point cloud data into three-dimensional models is performed by the processor. In response to user interaction, via the user interface  160 , the processor coupled with the display device  150  receives instructions relating to the modification of the displayed image and manipulates and modifies three-dimensional image model in accordance with the interactive instructions provided by the user in step  1012 .  
      In step  1014 , the user may selectively design an abutment or crown for the dental implant by modifying the displayed image at display device  160  through interaction with the user interface  160  coupled to the processor. Alternatively, the processor may be pre-programmed to automatically generate an abutment or dental crown design extending from a root portion of the imaged dental item based on preselected parameters relating to the images of the dental item.  
      In step  1016 , the processor at the imaging system  140  coupled to the display device  150  computes CNC tool-paths from the modified three-dimensional image model that may be displayed at the display device. In step  1018 , the CNC tool-path data is transferred from the processor coupled with display device  150 , at imaging system  140 , to the implant production device  170 . Alternatively, the modified three-dimensional image data may be transferred to the implant production device and the computation of the CNC tool-path data is performed at the implant production device. In step  1020 , the implant production device  170  machines the dental implant based on the tool-path data. In step  1022 , the produced dental implant is placed into the socket that previously retained an extracted tooth.  
      Although embodiments of the invention are described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the invention as described by the appended claims. While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.