Abstract:
The present invention is a three-dimensional scanner for use in the oral cavity. The scanner of the present invention utilizes three optical scanners in a single-hand wand to create three-dimensional images with a single pass of the wand over the area scanned. Processing of the collected images is then composited into a three-dimensional image for CAD/CAM restoration and diagnostic aid in dentistry. OCT technology may be utilized to generate the images.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to the field of dentistry and more particularly relates to a three-dimensional tomography system for imaging and diagnosing the oral cavity features contained within. 
       BACKGROUND OF THE INVENTION 
       [0002]    Three-dimensional image systems including image scanning, image computer processing, and machining of processed image have been widely used in dentistry and other fields. The key area is the imaging scanning process. Several products like CEREC™ by Sirona, E4D™ for Dentist and E4D™ for Laboratory by D4D Tech, ETREO™ by Cadent, Lava™ by 3M have used a laser scanning method or CCD to catch the image of the surface scanned and use proprietary algorithms to build three-dimensional images. Such systems require multiple scans in different directions in order to build three-dimensional images. The surface conditions are also highly restricted to obtain high quality images. These systems, then, can only generate three-dimensional images and do not have any diagnostic function. 
         [0003]    This invention is to use an optical technology in a three dimensional head to obtain three-dimensional images in the oral environment with one scan. The image will not only display the physical information of three-dimensional surface of the tooth, but also the integrity of tooth surface. This invention can also employ optical coherence tomography (OCT) technology in the system to generate images for diagnostics. 
       SUMMARY OF THE INVENTION 
       [0004]    In view of the foregoing disadvantages inherent in the known types of tomography scanners, this invention provides a three-dimensional tomography scanner. As such, the present invention&#39;s general purpose is to provide a new and improved three-dimensional scanner that provides three dimensional and diagnostic images with a single scan. To accomplish these objectives, the scanner comprises three optical scanning heads, each consisting with a micro electromechanical system (MEMS) like an endoscope probe used in medicine, which are set up at perpendicular directions (or special fixed directions with known relative angles) in order to cover the whole of a tooth. The system can also use OCT technologies to generate images for diagnostics. The system uses stereo matching to establish correspondence between the three images using proprietary methods, and a three dimensional image is thereby formed. 
         [0005]    The system is intended to take dental restoration to a high level of productivity, patient comfort, and convenience with its 3D CAD/CAM restorative system for dental offices and laboratories. The system can produce digital 3D impressions of teeth for a variety of needs including diagnostics and restorations. 
         [0006]    The more important features of the invention have thus been outlined in order that the more detailed description that follows may be better understood and in order that the present contribution to the art may better be appreciated. Additional features of the invention will be described hereinafter and will form the subject matter of the claims that follow. 
         [0007]    Many objects of this invention will appear from the following description and appended claims, reference being made to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views. 
         [0008]    Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. 
         [0009]    As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a schematic of the invented system. 
           [0011]      FIG. 2  is a perspective view in partial section, showing the structure of hand hold probe. 
           [0012]      FIG. 3  is a side plan view showing the structure of scanning head in  FIG. 2 . 
           [0013]      FIG. 4  is a schematic showing the layout of the scanning system. 
           [0014]      FIG. 5  is a flowchart depicting the process to form three dimensional images. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0015]    With reference now to the drawings, the preferred embodiment of the three-dimensional scanner is herein described. It should be noted that the articles “a”, “an”, and “the”, as used in this specification, include plural referents unless the content clearly dictates otherwise. 
         [0016]    With reference to  FIG. 1 ,  100  is the system itself while  101  is a hand probe with a three-dimensional scanning head. Cable  102  contains both optical fiber and electrical cables inside. Processing consol  103  includes controls for scanning heads, light sources, CCD cameras, and process CPU. Processing consol  103  is connected to computer  105  by cable  104 . Computer  105  is provided with customized software for imaging processing. U8i 
         [0017]      FIG. 2  depicts the hand probe ( FIG. 1 ,  101 ) used in the present invention, where  200  is the hand probe. Housing  201  provides open space  202  surrounded by three walls  203 ,  204 , and  205 , respectively. The open space  202  is sufficient to allow the probe  200  to encompass the objects to be scanned, teeth as illustrated in the figures, though other scanner sizes could be used to scan other objects and use the same structures, configurations and methods as described herein to generate three-dimensional images. The walls are made of transparent materials like quartz, glass, or plastic. Inside housing  201 , proximate each wall, there are three scanning heads. Scanning head  206  with a conduction cable  207  are proximate the facet of  203 . Scanning head  208  with a conduction cable  209  are proximate facet  204 . Scanning head  210  with a conduction cable  211  are proximate facet  205 . The conduction cables  207 ,  209 , and  211  include both optical and electrical cables and are generally contained in cable  102  in  FIG. 1 . 
         [0018]      FIG. 3  depicts a scanning head  300  ( 206 ,  208  and  210  in  FIG. 2 ). Housing  301  is made of transparent materials like quarts, glass, or plastic. Cable jacket  302  covers and protects optical fiber  307 , and power cable  309 . Micro-motor  303  is powered thorough power cable  309  and has a shaft  304  that can move along horizontal axis when rotating. A prism  305  is attached to the shaft so that prism can be rotated  360  degrees. A Graded index (“GRIN”) lens  306  is in front of prism  305 . Optical fiber  307  is attached to GRIN lens using epoxy  308 . The fiber  307  is used to transport the light source to prism  305  and transport the reflection light back to process center  103  ( FIG. 1 ). With a prism  305  moving in horizontal direction while rotating, the prism can transfer the light from fiber to an object surface  310 . The area that from which light can be collected depends on the reflection angle of prism and moving distance of prism. The light is reflected by the object surface  310 , back to prism  305 , collected by GRIN lens  306  and is transported through fiber  307  back to the process center  103 . Thus the image on the object can be formed. 
         [0019]    Three scanning probes, each in a different facet, can work independently to collect the surface image in different views. By using construction software, the images from different directions can be constructed to form a three-dimensional image. 
         [0020]      FIG. 4  illustrates to overall system  400 . The three-dimensional probe  401  as illustrated in  FIG. 3  is connected to cable  402 , containing both electrical and optical fiber cable. Electrical cable  403  branches from cable  402  and connects to control logic circuit  405  to control the micro-motor in the probe  401 . Electrical cable  406  connects control logic circuit  405  to computer  407 . Fiber cable  404  also branches from cable  402  and is connected to another fiber cable  409  through coupler  408 . Light source  410  is connected to fiber  409  and electrical cable  411 , which connects it to its control  412 . The light source can be a laser or LED, or other light sources that can be used for OCT. Electrical cable  413  connects light control  412  to computer  407 . Optical fiber cable  414  extends from coupler  408  and connects to detector  415 , which is used to detect return signals from the probe  401 . Electrical cable  416  connects detector  415  to computer  407  for data exchange. Spectrometer  418 , which is used to aid in the matching and integration of the images, is connected to computer  407  through electrical cable  41   9  and to the fiber coupler  408  through fiber cable  417 . The processing console  420  ( 103  in  FIG. 1 ) physically contains all of the above referenced components (at least partially) except the computer  407 , and the probe  401 . The electrical cables  405 ,  413 ,  416 , and  419  may connect individually to the computer  407  or may be combined into one multi-cable ( 104  in  FIG. 1 ). 
         [0021]    The working principle for scanning system is depicted in  FIG. 5 . The three images from the scanner are combined with calibration images (previously, later or contemporaneously obtained with the scanner images) and matched to yield three individual range images, each one including three-dimensional information for a surface. The range images are then integrated to form a three-dimensional model, from which three-dimensional shapes may be extracted for diagnosis. 
         [0022]    Although the present invention has been described with reference to preferred embodiments, numerous modifications and variations can be made and still the result will come within the scope of the invention. No limitation with respect to the specific embodiments disclosed herein is intended or should be inferred.