Apparatus and method for measuring optical characteristics of teeth

• US 6,573,984 B2
• Filed: 08/02/2001
• Issued: 06/03/2003
• Est. Priority Date: 06/30/1998
• Status: Expired due to Fees

• Current Assignee: RPX Corporation
• Original Assignee: LJ Laboratories L.L.C.
• Inventors: Loudermilk, Alan R., Jung, Wayne D., Jung, Russell W.
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): MERLINO, AMANDA H
• Application Number:
  US09/922,180
• Publication Number:
  US 20020003620A1
• Time in Patent Office: 670 Days
• Field of Search: 356/630, 356/73, 356/317-319, 356/326, 356/328, 356/371, 356/416, 356/417, 356/419, 356/445, 356/446
• US Class Current: 356/73
• CPC Class Codes: A61B 5/0088 for oral or dental tissue
• CPC Class Codes: G01J 2003/1217 Indexed discrete filters or choppers
• CPC Class Codes: G01J 2003/1234 Continuously variable IF [CVIF]; Wedge type
• CPC Class Codes: G01J 2003/468 of objects containing fluorescent agent
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/0264 Electrical interface; User interface
• CPC Class Codes: G01J 3/0272 Handheld
• CPC Class Codes: G01J 3/0278 Control or determination of height or angle information for sensors or receivers
• CPC Class Codes: G01J 3/0283 using a charging unit
• CPC Class Codes: G01J 3/0291 Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
• CPC Class Codes: G01J 3/463 Colour matching
• CPC Class Codes: G01J 3/508 measuring the colour of teeth
• CPC Class Codes: G01J 3/51 using colour filters
• CPC Class Codes: G01J 3/513 having fixed filter-detector pairs
• CPC Class Codes: G01J 3/524 Calibration of colorimeters
• CPC Class Codes: G01N 21/251 Colorimeters; Construction thereof
• CPC Class Codes: G01N 21/474 Details of optical heads therefor, e.g. using optical fibres
• CPC Class Codes: G01N 21/57 : Measuring gloss

Abstract

Optical characteristic measuring systems and methods such as for determining the color or other optical characteristics of teeth are disclosed. Perimeter receiver fiber optics are spaced apart from a source fiber optic and receive light from the surface of the object/tooth being measured. Light from the perimeter fiber optics pass to a variety of filters. The system utilizes the perimeter receiver fiber optics to determine information regarding the height and angle of the probe with respect to the object/tooth being measured. Under processor control, the optical characteristics measurement may be made at a predetermined height and angle. Various color spectral photometer arrangements are disclosed. Translucency, fluorescence, gloss and/or surface texture data also may be obtained. Audio feedback may be provided to guide operator use of the system. The probe may have a removable or shielded tip for contamination prevention. A method of producing dental prostheses based on measured data also is disclosed. Measured data also may be stored and/or organized as part of a patient data base.

Claims

1. A method comprising the steps of:

moving a probe in proximity to a dental object having a surface and including an enamel layer,

wherein the probe provides light to the surface of the object from one or more light sources, and receives light from the object through a plurality of light receivers,

wherein each of the plurality of light receivers comprises a light receiver that has a numerical aperture and a spacing from the one or more light sources that defines a critical height,

wherein, when the probe is a distance from the dental object that is less than the critical height for a particular light receiver, light that is reflected from the surface of the dental object is not received by the particular light receiver,

wherein the plurality of light receivers include one or more first light receivers baying a first critical height and one or more second light receivers having a second critical height different from the first critical height;

determining the intensity of light received by more than one of the light receivers; and

measuring the optical characteristics of the object, wherein the measurement produces data indicative of the optical characteristics of the object and a thickness of the enamel layer of the dental object.

2. The method of claim 1, wherein the optical characteristics of the object comprise color characteristics.

3. The method of claim 1, wherein the optical characteristics of the object comprise translucence characteristics.

4. The method of claim 1, wherein the optical characteristics of the object comprise fluorescence characteristics.

5. The method of claim 1, wherein the optical characteristics of the object comprise surface texture characteristics.

6. The method of claim 1, wherein the optical characteristics of the object comprise gloss characteristics.

7. The method of claim 1, further comprising the step of preparing a second dental object based on the optical characteristics.

8. The method of claim 1, further comprising the step of transmitting data indicative of the measured optical characteristics to a remote location, and preparing a second dental object based on the measured optical characteristics at the remote location.

9. The method of claim 1, further comprising the steps of;

generating first data corresponding to characteristics of a type of object being measured;

comparing the first data with the measured optical characteristics; and

assessing a condition of the abject based on the comparison.

10. The method of claim 9, wherein the condition comprises a condition relating to a subsurface feature of the object.

11. The method of claim 1, wherein color spectrum data is adjusted based on gloss data.

12. The method of claim 1, wherein color spectrum data is adjusted based on translucency data.

13. The method of claim 1, wherein color spectrum data is adjusted based on gloss and translucency data.

14. The method of claim 1, further comprising the steps of:

capturing an image of the object with a camera; and

storing the captured image.

15. The method of claim 14, further comprising the step of correlating the data indicative of the measured optical characteristics with the captured image, wherein the captured image includes indicia of the location at which the optical characteristics were measured.

16. The method of claim 14, further comprising the steps of;

postureizing the object into at least first and second regions;

measuring optical characteristics of the object in the first and second regions;

correlating data indicative of the optical characteristics in the first and second regions with the captured image, wherein the captured image includes indicia of the first and second regions.

17. The method of claim 16, further comprising the step of preparing a second dental object based on the optical characteristics.

18. The method of claim 16, further comprising the step of transmitting data indicative of the optical characteristics to a remote location, and preparing a second dental object based on the measured optical characteristics at the remote location.

19. The method of claim 14, further comprising the step of displaying an image on a display, wherein the displayed image includes an image of the object and information indicative of optical characteristics of the object.

20. The method of claim 19, wherein the information indicative of the optical characteristics of the object is displayed at least in part in an overlaid manner over the image of the object.

21. The method of claim 1, wherein the probe is coupled to a dental chair adapted to hold the probe during a time when the probe is not taking measurements.

22. The method of claim 1, wherein the probe includes a removable tip.

23. The method of claim 1 wherein the probe is covered by a removable shield.

24. The method of claim 21, wherein the shield is disposable.

25. The method of claim 1, wherein data indicative of the determined optical characteristics is coupled to a material preparation device, wherein the material preparation device prepares materials based on the measured optical characteristics.

26. The method of claim 1, wherein the data indicative of optical characteristics include a specular-included spectrum and a specular-excluded spectrum, wherein the specular-included spectrum substantially includes light specularly reflected from the object, and wherein the specular-excluded substantially excludes light specularly reflected from the object.

27. The method of claim 1, wherein light from one or more of the light receivers is coupled to one or more sensors, wherein the one or more sensors generate at least one signal having a frequency proportional to the light intensity received by the one or more sensors.

28. The method of claim 27, wherein the at least one signal comprises a digital signal.

29. The method of claim 28, wherein the digital signal comprises a TTL or CMOS digital signal.

30. The method of claim 27, wherein the light passes through a filter prior to being coupled to one or more of the sensors, wherein the optical characteristics are measured based on measuring a period of a plurality of digital signals produced by a plurality of sensors.

31. The method of claim 27, wherein the signal comprises an asynchronous signal of a frequency dependent upon the intensity of the received light.

32. The method of claim 27, wherein the one or more sensors comprise a plurality of light to frequency converter sensing elements.

33. The method of claim 27, wherein the light passes through a filter prior to being coupled to one or more of the sensors, wherein the filter comprises a plurality of filter portions having a wavelength dependent optical transmission property.

34. The method of claim 27, wherein the optical characteristics comprise a spectral analysis based on light received from the object.

35. Thc method of claim 27, wherein the light passes through a filter prior to being coupled to one or more of the sensors, wherein the filter comprises a plurality of cut-off filter elements.

36. The method of claim 27, wherein the light passes through a filter prior to being coupled to one or more of the sensors, wherein the filter comprises a color gradient filter.

37. The method claim 27, wherein the light passes through a filter prior to being coupled to one or more of the sensors, wherein the filter comprises a filter grid.

38. The method of claim 27, wherein the light passes through a filter prior to being coupled to one or more of the sensors, wherein the received light is spectrally analyzed without using a diffraction grating.