WO1991002955A1 - Shade distinguishing device - Google Patents

Shade distinguishing device Download PDF

Info

Publication number
WO1991002955A1
WO1991002955A1 PCT/GB1990/001288 GB9001288W WO9102955A1 WO 1991002955 A1 WO1991002955 A1 WO 1991002955A1 GB 9001288 W GB9001288 W GB 9001288W WO 9102955 A1 WO9102955 A1 WO 9102955A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
shade
distinguishing device
detector
signal
Prior art date
Application number
PCT/GB1990/001288
Other languages
French (fr)
Inventor
Sameul Thomas John Mckeown
Original Assignee
Sameul Thomas John Mckeown
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sameul Thomas John Mckeown filed Critical Sameul Thomas John Mckeown
Publication of WO1991002955A1 publication Critical patent/WO1991002955A1/en

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C19/00—Dental auxiliary appliances
    • A61C19/10—Supports for artificial teeth for transport or for comparison of the colour
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/46—Measurement of colour; Colour measuring devices, e.g. colorimeters
    • G01J3/50—Measurement of colour; Colour measuring devices, e.g. colorimeters using electric radiation detectors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/46—Measurement of colour; Colour measuring devices, e.g. colorimeters
    • G01J3/50—Measurement of colour; Colour measuring devices, e.g. colorimeters using electric radiation detectors
    • G01J3/501—Colorimeters using spectrally-selective light sources, e.g. LEDs
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/46—Measurement of colour; Colour measuring devices, e.g. colorimeters
    • G01J3/50—Measurement of colour; Colour measuring devices, e.g. colorimeters using electric radiation detectors
    • G01J3/508—Measurement of colour; Colour measuring devices, e.g. colorimeters using electric radiation detectors measuring the colour of teeth
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J2001/4242—Modulated light, e.g. for synchronizing source and detector circuit

Definitions

  • This invention relates to a shade distinguishing device.
  • a shade distinguishing device comprising a light source for projecting light towards an object, light detecting means for receiving light reflected from said object and which produces an output signal the magnitude of said signal being dependent on the intensity of light incident on the detecting means and means for producing an audio or visual display representative of the magnitude of said signal.
  • the light source is a light emitting diode.
  • each producing light at a different wavelength particularly in the ranges including red, yellow, green and blue light.
  • the detecting means is a diode which produces a voltage signal the magnitude of the signal being dependent on the intensity of the incident light.
  • the detector is shielded in order to limit the detection of scattered or spurious light.
  • signals produced by the detection of spurious light are deleted by the modulation of the light source at a known frequency and the use of phase sensitive detection of the reflected light, at the said frequency.
  • phase sensitive detection is provided by the inclusion of a lock-in amplifier system.
  • the light source and detector are relatively positioned so that light emitted by the source will be detected by the detector only if the light is reflected from a surface at a set distance from the light source and detector.
  • the surface is a tooth and the intensity of light on the detector is dependent on the proportion of the light, incident on the tooth, which is reflected by the tooth enamel.
  • the signal is processed by an analogue to digital converter to drive a digital display.
  • the analogue to digital converter is in the form of a pre-programmed micro-chip.
  • the digital display is a seven segment liquid crystal display.
  • Fig. 1 is a side elevation of a shade distinguishing device in accordance with the present invention
  • Fig. 2 is a plan view of the shade distinguishing device if Fig. 1 '
  • Fig. 3 is a block diagram of the shade distinguishing device of Fig. 1.
  • Figs. 1 and 2 show a shade distinguishing device including a plastics housing 6 one end of which is attached to an operating head 7 containing a light source in the form of a light emitting diode 1 and a light detector 2 in the form of a diode which produces a voltage signal the magnitude of the signal being dependent on the intensity of the light incident on the detector 2.
  • the main body of the housing 6 contains a means of processing the signal, in the form of a pre-programmed micro-chip which converts the analogue signal produced by the detector 2 to a digital signal which is displayed on an array of three liquid crystal diodes 3.
  • Fig. 3 is a block diagram showing how the shade distinguishing device will show a unique number on the display corresponding to the colour and shade of the object under test.
  • the sample is illuminated sequentially by various colour light emitting diodes and the light reflected back from the sample is measured using a photodiode.
  • phase sensitive measurement system In any practical measurement the signals will be accompanied by unwanted noise energy that limits the sensitivity that can be obtained.
  • An a.c. phase sensitive measurement system is used in order to improve the signal to noise ratio and provide some immunity to strong light entering the detector.
  • the phase sensitive detector has the ability to resolve a signal from broadband noise many times the amplitude of the signal to be measured.
  • a lock-in amplifier measurement system is used which incorporates a modulation circuit, selective ampli ication, synchronous demodulation and low pass filtering.
  • the light emitting diodes are modulated at a discreet frequency in a region of minimal noise well removed from low frequency flicker noise and interference such as mains pick-up.
  • Logic circuitry sequentially turns on each light emitting diode for a short period in turn.
  • a driver circuit is used to provide sufficient current drive to the light emitting diodes.
  • the signal from the detector first undergoes wideband filtering and amplification.
  • a band pass filter is used to remove any large interference signals which could saturate the output of the phase detector.
  • the modulated signal is synchronously detected using the reference signal to form the product in a multiplier circuit.
  • the reference signal is derived from the same source as the signal and must be phase coherent.
  • the output from the synchronous detector is then converted to a d.c. signal by an integrator and low pass filter. This provides a narrow bandwidth and removes any higher order a.c. components in the signal.
  • the d.c. signal is then converted to a digital code using an analogue to digital convertor. At the end of conversion the output from the A/D convertor is latched into a shift register for storage.
  • a separate shift register is used for each light emitting diode.
  • the outputs from the shift registers are connected to the address lines of then memory device and are used to select a unique address on the chip. The address selected will therefore depend on the level of the measurement signal.
  • the memory device is pre-programmed with a unique number in each location.
  • the memory devices are configured as READ ONLY and therefore the date lines will correspond to the binary code of the location selected by the address lines.
  • the data from the memory device is processed " into a suitable form for the digital display which is updated at the end of each cycle of measurements.
  • the means of actuating the shade distinguishing device is in the form of an operating button 4.
  • a dentist or other user would place the open end 5 of the operating head 7 over a patients' tooth, thus positioning the light emitting diode l and light detector 2 at a set distance from the tooth. In this way the maximum amount of light emitted by the diode 1 and reflected off of the tooth falls incident on the detector 2.
  • the light incident on the tooth is either absorbed, transmitted or reflected.
  • the proportion of the light reflected is dependent on the shade of the tooth; a black tooth reflecting no light and a pure white tooth reflecting all of the incident light. Therefore, the proportion of the light reflected is determined by the shade of the tooth and the voltage signal produced by the detector is determined by the intensity of this light incident on the detector.
  • the voltage signal produced by the detector provides an accurate measure of the shade of a tooth.
  • the voltage signal is converted from an analogue to a digital signal for ease of display, using a three digit liquid crystal diode display 3.
  • the voltage signal provided by the shade distinguishing device can be compared to the signal obtained from each of the 16 shades available from a Vita (TM) shade guide.
  • TM Vita
  • the electronic shade indicator will enable the exact matching of any tooth shade to that of a porcelain, which can be used to produce dentures or crowns or other dental requirements.

Abstract

A shade distinguishing device comprising a casing (6) having a light source (1) and detector (2). The light source and detector being relatively positioned so that a proportion of the light emitted by the detecteur, and falling incident on an object, is reflected onto the detector. The proportion of the light detected being dependent on the colour and shade of the object. The signal from the detector being processed to produce an accurate signal representative of the shade and colour of the object, which is displayed on a liquid crystal display (3).

Description

"Shade Dis inguishing Device"
This invention relates to a shade distinguishing device.
In addition to the primary task of caring for patients' teeth and gums dentists today also have to be aware of the cosmetic side of their work. Patients whether they require fillings, caps, veneers or dentures want them to blend and match.their own teeth. The most important part of this matching process is colour or shade matching.
At present shade matching is achieved by a dentist who visually matches the shade of a patients' teeth with a 16 shade guide. This is both an extremely time consuming and an inadequate process. With only 16 shades to choose from many patients' teeth cannot be matched perfectly. This problem is compounded both by dentists not always having time for an accurate • matching and by the shading on the charts fading with age. These problems added to the fact that many dentists and technicians do not have perfect colour vision results, in many cases in an extremely poor shade match and visually obvious dental work for the patien .
The provision of a device which can provide an accurate measure of teeth shading is therefore extremely desirable.
According to the present invention there is provided a shade distinguishing device comprising a light source for projecting light towards an object, light detecting means for receiving light reflected from said object and which produces an output signal the magnitude of said signal being dependent on the intensity of light incident on the detecting means and means for producing an audio or visual display representative of the magnitude of said signal.
Preferably, the light source is a light emitting diode.
Most preferably, there is a plurality of light sources, each producing light at a different wavelength, particularly in the ranges including red, yellow, green and blue light.
Preferably, the detecting means is a diode which produces a voltage signal the magnitude of the signal being dependent on the intensity of the incident light.
Preferably, the detector is shielded in order to limit the detection of scattered or spurious light.
Preferably, signals produced by the detection of spurious light are deleted by the modulation of the light source at a known frequency and the use of phase sensitive detection of the reflected light, at the said frequency. Most preferably phase sensitive detection is provided by the inclusion of a lock-in amplifier system.
Preferably/ the light source and detector are relatively positioned so that light emitted by the source will be detected by the detector only if the light is reflected from a surface at a set distance from the light source and detector.
Most preferably, the surface is a tooth and the intensity of light on the detector is dependent on the proportion of the light, incident on the tooth, which is reflected by the tooth enamel.
Preferably, the signal is processed by an analogue to digital converter to drive a digital display.
Most preferably, the analogue to digital converter is in the form of a pre-programmed micro-chip.
Preferably, the digital display is a seven segment liquid crystal display.
An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings in which:
Fig. 1 is a side elevation of a shade distinguishing device in accordance with the present invention; Fig. 2 is a plan view of the shade distinguishing device if Fig. 1'; and Fig. 3 is a block diagram of the shade distinguishing device of Fig. 1. Referring to the drawings, Figs. 1 and 2 show a shade distinguishing device including a plastics housing 6 one end of which is attached to an operating head 7 containing a light source in the form of a light emitting diode 1 and a light detector 2 in the form of a diode which produces a voltage signal the magnitude of the signal being dependent on the intensity of the light incident on the detector 2. The main body of the housing 6 contains a means of processing the signal, in the form of a pre-programmed micro-chip which converts the analogue signal produced by the detector 2 to a digital signal which is displayed on an array of three liquid crystal diodes 3.
Fig. 3 is a block diagram showing how the shade distinguishing device will show a unique number on the display corresponding to the colour and shade of the object under test.
The sample is illuminated sequentially by various colour light emitting diodes and the light reflected back from the sample is measured using a photodiode.
In any practical measurement the signals will be accompanied by unwanted noise energy that limits the sensitivity that can be obtained. An a.c. phase sensitive measurement system is used in order to improve the signal to noise ratio and provide some immunity to strong light entering the detector. The phase sensitive detector has the ability to resolve a signal from broadband noise many times the amplitude of the signal to be measured. A lock-in amplifier measurement system is used which incorporates a modulation circuit, selective ampli ication, synchronous demodulation and low pass filtering. The light emitting diodes are modulated at a discreet frequency in a region of minimal noise well removed from low frequency flicker noise and interference such as mains pick-up. Logic circuitry sequentially turns on each light emitting diode for a short period in turn. A driver circuit is used to provide sufficient current drive to the light emitting diodes.
The signal from the detector first undergoes wideband filtering and amplification. A band pass filter is used to remove any large interference signals which could saturate the output of the phase detector.
The modulated signal is synchronously detected using the reference signal to form the product in a multiplier circuit. This enables the system to discriminate against random noise components. The reference signal is derived from the same source as the signal and must be phase coherent. The output from the synchronous detector is then converted to a d.c. signal by an integrator and low pass filter. This provides a narrow bandwidth and removes any higher order a.c. components in the signal. The d.c. signal is then converted to a digital code using an analogue to digital convertor. At the end of conversion the output from the A/D convertor is latched into a shift register for storage.
A separate shift register is used for each light emitting diode. The outputs from the shift registers are connected to the address lines of then memory device and are used to select a unique address on the chip. The address selected will therefore depend on the level of the measurement signal. The memory device is pre-programmed with a unique number in each location. The memory devices are configured as READ ONLY and therefore the date lines will correspond to the binary code of the location selected by the address lines. The data from the memory device is processed " into a suitable form for the digital display which is updated at the end of each cycle of measurements.
The means of actuating the shade distinguishing device is in the form of an operating button 4.
In use a dentist or other user would place the open end 5 of the operating head 7 over a patients' tooth, thus positioning the light emitting diode l and light detector 2 at a set distance from the tooth. In this way the maximum amount of light emitted by the diode 1 and reflected off of the tooth falls incident on the detector 2.
The light incident on the tooth is either absorbed, transmitted or reflected. The proportion of the light reflected is dependent on the shade of the tooth; a black tooth reflecting no light and a pure white tooth reflecting all of the incident light. Therefore, the proportion of the light reflected is determined by the shade of the tooth and the voltage signal produced by the detector is determined by the intensity of this light incident on the detector.
Thus the voltage signal produced by the detector provides an accurate measure of the shade of a tooth. The voltage signal is converted from an analogue to a digital signal for ease of display, using a three digit liquid crystal diode display 3.
The voltage signal provided by the shade distinguishing device can be compared to the signal obtained from each of the 16 shades available from a Vita (TM) shade guide. As the shades of porcelain produced by Vita (TM) and other manufacturers increase the electronic shade indicator will enable the exact matching of any tooth shade to that of a porcelain, which can be used to produce dentures or crowns or other dental requirements.
In this way the introduction of a shade distinguishing device in accordance with the present invention not only enables more accurate use of the presently available shades of porcelain but also facilitates the introduction and use of a much wider range of shades of porcelain.
Modifications and improvements may be incorporated without departing from the scope of the invention.

Claims

Claims
1. A shade distinguishing device comprising a light source for projecting light towards an object, light detecting means for receiving light reflected from said object and which produces a signal, the magnitude of said signal being dependent on the intensity of light incident on the detecting means and means for producing an audio or visual display representative of the magnitude of said signal.-
2. A shade distinguishing device as claimed in Claim 1, wherein the light source is a light emitting diode.
3. A shade distinguishing device as claimed in Claim 2, wherein the device includes a plurality of light emitting diodes each providing light at a different wavelength, thus allowing the device to distinguish between colours.
4. A shade distinguishing device as claimed in Claim 3, wherein a logic circuit is provided to operate each light emitting diode in sequence.
5. A shade distinguishing device as claimed in any preceeding claim, wherein the detector is shielded in order to limit the detection of scattered or spurious light.
6. A shade distinguishing device as claimed in any preceeding claim, wherein the signals produced by scattered or spurious light are deleted by the modulation of the light source at a known frequency and the use of phase sensitive detection of the reflected light at the said frequency.
7. A shade distinguishing device as claimed in Claim 6, wherein a lock-in amplifier system is used.
8. A shade distinguishing device as claimed in any preceeding claim, wherein the light source and detector are relatively positioned so that light emitted by the light source will be detected by the detector only if the light is reflected from a surface at a set distance from the light source and detector.
9. A shade distinguishing device as claimed in Claim 8, wherein the surface is a tooth and the intensity of light incident on the detector is dependent on the proportion of the light, incident on the tooth, which is reflected by the tooth enamel.
10. A shade distinguishing device as claimed. in any preceeding claim wherein the signal is processed by an analogue to digital convertor in the form of a pre-programmed micro-chip, to drive a digital display.
11. A shade distinguishing device as claimed in any preceeding claim, wherein the device is powered by a power cell such as a battery.
PCT/GB1990/001288 1989-08-15 1990-08-15 Shade distinguishing device WO1991002955A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB898918605A GB8918605D0 (en) 1989-08-15 1989-08-15 Shade distinguishing device
GB8918605.0 1989-08-15

Publications (1)

Publication Number Publication Date
WO1991002955A1 true WO1991002955A1 (en) 1991-03-07

Family

ID=10661658

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1990/001288 WO1991002955A1 (en) 1989-08-15 1990-08-15 Shade distinguishing device

Country Status (2)

Country Link
GB (1) GB8918605D0 (en)
WO (1) WO1991002955A1 (en)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5690486A (en) * 1995-07-28 1997-11-25 Dentalase Corporation Dental tooth color detector apparatus and method
WO1998012985A1 (en) * 1996-09-26 1998-04-02 Brien William J O Tooth color matching system
ES2113826A1 (en) * 1996-06-11 1998-05-01 Rodriguez Salgado Santiago Portable colorimeter for dental prostheses.
US5766006A (en) * 1995-06-26 1998-06-16 Murljacic; Maryann Lehmann Tooth shade analyzer system and methods
US6210159B1 (en) 1998-05-20 2001-04-03 Shade Analyzing Technologies, Inc. System and methods for analyzing tooth shades
US6575751B1 (en) 1998-11-03 2003-06-10 Shade Analyzing Technologies, Inc. Interactive dental restorative network
US7118374B2 (en) 2003-06-09 2006-10-10 Ivoclar Vivadent Ag Enhanced tooth shade guide
US7341450B2 (en) 2003-10-03 2008-03-11 Shade Analyzing Technologies, Inc. Tooth shade scan system and method
US8386061B2 (en) 2008-06-02 2013-02-26 Dentsply International Inc. Methods for designing a customized dental prosthesis using digital images of a patient
US8790118B2 (en) 1998-11-03 2014-07-29 Shade Analyzing Technologies, Inc. Interactive dental restorative network

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2188157A1 (en) * 1972-06-01 1974-01-18 Swinson William E
US3910701A (en) * 1973-07-30 1975-10-07 George R Henderson Method and apparatus for measuring light reflectance absorption and or transmission
EP0109686A2 (en) * 1982-11-22 1984-05-30 Hitachi Maxell Ltd. Color sensor
EP0114515A2 (en) * 1982-12-22 1984-08-01 Development Finance Corporation Of New Zealand Method and apparatus for colour recognition
WO1987003470A1 (en) * 1985-12-13 1987-06-18 Bertin & Cie Method and device for determining the colour, particularly of a dental prosthesis
EP0256970A2 (en) * 1986-08-05 1988-02-24 Fritz Kurandt Device for the fast colour measuring of different samples
JPH01164361A (en) * 1987-12-21 1989-06-28 Shigeru Onozuka Dental hue measuring apparatus
EP0360657A1 (en) * 1988-09-09 1990-03-28 Bertin & Cie Method for determining the colour of an object, particularly of a dental prosthesis
EP0375317A2 (en) * 1988-12-20 1990-06-27 E.I. Du Pont De Nemours And Company Portable colorimeter and method for characterization of a colored surface

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2188157A1 (en) * 1972-06-01 1974-01-18 Swinson William E
US3910701A (en) * 1973-07-30 1975-10-07 George R Henderson Method and apparatus for measuring light reflectance absorption and or transmission
EP0109686A2 (en) * 1982-11-22 1984-05-30 Hitachi Maxell Ltd. Color sensor
EP0114515A2 (en) * 1982-12-22 1984-08-01 Development Finance Corporation Of New Zealand Method and apparatus for colour recognition
WO1987003470A1 (en) * 1985-12-13 1987-06-18 Bertin & Cie Method and device for determining the colour, particularly of a dental prosthesis
EP0256970A2 (en) * 1986-08-05 1988-02-24 Fritz Kurandt Device for the fast colour measuring of different samples
JPH01164361A (en) * 1987-12-21 1989-06-28 Shigeru Onozuka Dental hue measuring apparatus
EP0360657A1 (en) * 1988-09-09 1990-03-28 Bertin & Cie Method for determining the colour of an object, particularly of a dental prosthesis
EP0375317A2 (en) * 1988-12-20 1990-06-27 E.I. Du Pont De Nemours And Company Portable colorimeter and method for characterization of a colored surface

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, Volume 13, No. 427 (C-639), 22 September 1989, & JP, A, 01164361 (Shigeru Onozuka) 28 June 1989 see Abstract *

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6832913B2 (en) 1995-06-26 2004-12-21 Shade Analyzing Technologies, Inc. Tooth shade analyzer system and methods
US7946845B2 (en) 1995-06-26 2011-05-24 Shade Analyzing Technologies, Inc. Tooth shade analyzer system and methods
US5766006A (en) * 1995-06-26 1998-06-16 Murljacic; Maryann Lehmann Tooth shade analyzer system and methods
US5961324A (en) * 1995-06-26 1999-10-05 Shade Analyzing Technologies, Inc. Tooth shade analyzer system and methods
US7393209B2 (en) 1995-06-26 2008-07-01 Shade Analyzing Technologies, Inc. Tooth shade analyzer system and methods
US6358047B2 (en) 1995-06-26 2002-03-19 Shade Analyzing Technologies, Inc. Tooth shade analyzer system and methods
US5690486A (en) * 1995-07-28 1997-11-25 Dentalase Corporation Dental tooth color detector apparatus and method
ES2113826A1 (en) * 1996-06-11 1998-05-01 Rodriguez Salgado Santiago Portable colorimeter for dental prostheses.
US6007332A (en) * 1996-09-26 1999-12-28 O'brien; William J. Tooth color matching system
WO1998012985A1 (en) * 1996-09-26 1998-04-02 Brien William J O Tooth color matching system
US6210159B1 (en) 1998-05-20 2001-04-03 Shade Analyzing Technologies, Inc. System and methods for analyzing tooth shades
US6786726B2 (en) 1998-11-03 2004-09-07 Shade Analyzing Technologies, Inc. Interactive dental restorative network
US6575751B1 (en) 1998-11-03 2003-06-10 Shade Analyzing Technologies, Inc. Interactive dental restorative network
US7581953B2 (en) 1998-11-03 2009-09-01 Shade Analyzing Technologies, Inc. Interactive dental restorative network
EP2133820A2 (en) 1998-11-03 2009-12-16 Shade Analyzing Technologies, Inc. System and methods for analyzing tooth shades
US8105084B2 (en) 1998-11-03 2012-01-31 Shade Analyzing Technologies, Inc. Interactive dental restorative network
US8790118B2 (en) 1998-11-03 2014-07-29 Shade Analyzing Technologies, Inc. Interactive dental restorative network
US8851893B2 (en) 1998-11-03 2014-10-07 Shade Analyzing Technologies, Inc. Interactive dental restorative network
US7118374B2 (en) 2003-06-09 2006-10-10 Ivoclar Vivadent Ag Enhanced tooth shade guide
US7341450B2 (en) 2003-10-03 2008-03-11 Shade Analyzing Technologies, Inc. Tooth shade scan system and method
US8386061B2 (en) 2008-06-02 2013-02-26 Dentsply International Inc. Methods for designing a customized dental prosthesis using digital images of a patient

Also Published As

Publication number Publication date
GB8918605D0 (en) 1989-09-27

Similar Documents

Publication Publication Date Title
US4773422A (en) Single channel pulse oximeter
US7244122B2 (en) Methods for determining optical characteristics of dental objects
US7062307B2 (en) Oversampling pulse oximeter
EP0104772B1 (en) Calibrated optical oximeter probe
USRE33643E (en) Pulse oximeter with circuit leakage and ambient light compensation
Zenthöfer et al. Comparison of the Easyshade Compact and Advance in vitro and in vivo
JPS63501930A (en) In particular, methods and devices for determining the color of dentures.
US20050181333A1 (en) System and method for detecting dental caries
WO1991002955A1 (en) Shade distinguishing device
US20150297089A1 (en) Dental apparatus and method of utilizing the same
Kim Evaluation of the repeatability and matching accuracy between two identical intraoral spectrophotometers: an in vivo and in vitro study
Rueggeberg Precision of hand-held dental radiometers.
US4537573A (en) Detector for diagnosing dental caries
EP0329196B1 (en) Oximeter for cooperation with an oximeter probe
YILMAZ et al. Comparison of visual shade determination and an intra‐oral dental colourimeter
US3802783A (en) Color shade analyzer
US4624572A (en) Non-invasive reflectance spectrophotometric apparatus
Hassel et al. Intraexaminer reliability of measurement of tooth color by spectrophotometry.
JPS5991326A (en) Method and device for measuring color luminance brightness
RU2054884C1 (en) Photoplethysmograph
SU1377605A1 (en) Spectrophotometer
SU795190A1 (en) Radiometric device
JPH0344531B2 (en)
JPS60114727A (en) Flicker meter
JPS62286435A (en) Brain wave detector

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CA JP US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB IT LU NL SE

NENP Non-entry into the national phase

Ref country code: CA