Drive noise tolerant plaque detection

Patent metadata

Field	Value
Publication number	US-2015305626-A1
Application number	US-201314442813-A
Country	US
Kind code	A1
Filing date	Dec 19, 2013
Priority date	Dec 19, 2012
Publication date	Oct 29, 2015
Grant date	—

Abstract

A dental implement ( 4 ) is presented that includes, in one embodiment, a light source ( 331 ) configured to emit an excitation light, and at least one optical unit for removing reflected excitation light and receiving a fluorescence light beam from the teeth. The dental implement further includes a detector ( 333 ) configured to receive the fluorescence light beam for detecting plaque and communicating a plaque identification signal of the teeth based on frequency domain lifetime measurements via a plaque detection circuit configured to reduce noise generated by a drive train at a drive train frequency (f dt ). The plaque identification signal is demodulated to an intermediate frequency (f IF ) such that the drive train frequency and the intermediate frequency are derived from a same master clock.

First claim

1 . A dental implement, comprising:
a drive train having a drive train frequency (f dt ); a light source configured to emit an excitation light; and a plaque detector configured to receive a return light beam from the teeth for generating a plaque identification signal; wherein the plaque detector demodulates identification signal to an intermediate frequency (f IF ) such that the drive train frequency (f dt ) and the intermediate frequency (f IF ) are derived from a same master clock (f 0 ).

2 . The dental implement according to claim 1 , further comprising an oscillator for modulating the light source.

3 . The dental implement according to claim 1 or the method, wherein the return light is fluorescence light.

4 . The dental implement according to claim 3 , further comprising at least one optical unit for removing reflected excitation light and receiving a fluorescence light beam from the teeth,
wherein the plaque detector is configured to receive the fluorescence light beam for detecting plaque and communicating a plaque identification signal of the teeth based on frequency domain lifetime measurements via a plaque detection circuit configured to reduce noise generated by a frequency drive train.

5 . The dental implement according to claim 1 , wherein the intermediate frequency (f IF ) is equal to the drive train frequency (f dt ) multiplied by (n+j/k), where “n” is an integer, “j” is a positive integer, and “k” is an even positive integer such that 0<j<k.

6 . The dental implement according to claim 5 , wherein “k” is chosen such that a bandwidth of the plaque identification signal is less than a frequency of the drive train divided by “k.”

7 . The dental implement according to claim 1 , wherein the plaque detector digitizes the demodulated intermediate frequency signal at a frequency that is an integer multiplier at least twice its frequency.

8 . The dental implement according to claim 1 , wherein the drive train varies the drive train frequency (f dt ) for a plurality of cleaning modes.

9 . The dental implement according to claim 1 , wherein an oscillator is the source used to generate the excitation light.

10 . The dental implement according to claim 1 , wherein the plaque detector demodulates the plaque identification signal to the intermediate frequency (f IF ) to prevent harmonic interference with the plaque identification signal.

11 . A method of detecting plaque on teeth via a dental implement having a drive train having a drive train frequency (f dt ), the method comprising:
providing an excitation light; receiving a return light beam from the teeth; generating a plaque identification signal from the return light beam; and demodulating the plaque identification signal to an intermediate frequency (f IF ) such that the drive train frequency (f dt ) and the intermediate frequency (f IF ) are derived from a same master clock.

12 . The method according to claim 11 , wherein the intermediate frequency (f IF ) is equal to the drive train frequency (f dt ) multiplied by (n+j/k), where “n” is an integer, “j” is a positive integer, and “k” is an even positive integer such that 0<j<k.

13 . The method according to claim 12 , wherein “k” is chosen such that a bandwidth of the plaque identification signal is less than a frequency of the drive train divided by “k.”

14 . The method according to claim 11 , further comprising digitizing the demodulated intermediate frequency signal at a frequency that is an integer multiplier at least twice its frequency.

15 . The method according to claim 11 , further comprising varying the drive train frequency (f dt ) based on a plurality of cleaning modes.

Assignees

• Koninkl Philips Nv

Inventors

• Deane Steven Charles
• Davie Alan James

Classifications

• A61B5/7228

  Signal modulation applied to the input signal sent to patient or subject; Demodulation to recover the physiological signal · CPC title

• G01N21/645

  Specially adapted constructive features of fluorimeters · CPC title

• A61B5/7282

  Event detection, e.g. detecting unique waveforms indicative of a medical condition (cough events A61B5/0823; seizures A61B5/4094; sleep apnoea A61B5/4818) · CPC title

• G01N21/6486

  Measuring fluorescence of biological material, e.g. DNA, RNA, cells (G01N21/6428 takes precedence) · CPC title

• A61B5/0088 Primary

  for oral or dental tissue · CPC title