Wavelength Modulated Plaque Detection Harmonics
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Solution Overview
Problem
Existing plaque detection methods struggle to differentiate between young and mature plaque and are hindered by interference from dental hard tissue and fillings, making real-time plaque detection during brushing unreliable.
Innovation Solution
The method employs wavelength modulation of a probing light source to generate harmonics based on the non-linear absorption and fluorescence excitation spectrum of plaque, allowing for synchronous detection of these harmonics to distinguish between different types of plaque and suppress background signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional plaque detection methods are used, then plaque can be detected, but the detection is unreliable due to interference from dental hard tissue and fillings
Solution Approach 1:
The patent applies dynamics by modulating the wavelength of the probing light source over time rather than using a fixed wavelength. This dynamic wavelength modulation allows the system to scan through multiple wavelengths and identify characteristic absorption patterns of plaque versus dental hard tissue and fillings, thereby achieving reliable differentiation despite interference from these materials.
Solution Approach 2:
The patent changes the parameter of light wavelength dynamically during detection. By sweeping through a range of wavelengths and measuring absorption at each point, the system captures the unique spectral fingerprint of plaque. This parameter change enables differentiation between plaque and interfering materials like dental hard tissue and fillings, which have different absorption characteristics across the wavelength spectrum.
2Productivity
If real-time plaque detection during brushing is implemented, then users receive immediate feedback, but the detection must be reliable amidst toothpaste foam and vibrating brush interference
Solution Approach 1:
The system uses dynamic wavelength modulation to continuously scan through wavelengths during brushing. This dynamic approach allows real-time detection by rapidly acquiring spectral data even in the presence of toothpaste foam and brush vibration. The modulation frequency is chosen to be higher than the vibration frequency of the brush, allowing the detection system to distinguish between the intentional wavelength modulation and unwanted mechanical vibrations.
Solution Approach 2:
The patent converts the harmful effect of brush vibration into a beneficial signal by using frequency domain analysis. By modulating the light wavelength at a known frequency higher than the brush vibration frequency, and then analyzing the detected signal in the frequency domain, the system can identify and extract the plaque detection signal from the vibration noise. The vibration that would normally interfere with detection is instead used as a reference to filter out noise.
3Measurement precision
If young and mature plaque are to be distinguished, then more detailed plaque characterization is achieved, but the detection complexity increases
Solution Approach 1:
The patent uses parameter changes in wavelength to differentiate between young and mature plaque. Different plaque types have distinct absorption spectra due to their different compositions and maturation states. By measuring absorption across multiple wavelengths and analyzing the spectral pattern, the system can identify characteristic signatures of young versus mature plaque without requiring complex additional hardware.
Solution Approach 2:
The patent replaces complex mechanical or chemical analysis systems with an optical spectroscopy approach. Instead of using complicated devices to analyze plaque composition, the system uses wavelength-modulated light absorption measurements, which are simpler and more suitable for integration into a portable oral care device. This substitution maintains measurement precision while reducing device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable real-time plaque detection during brushing by effectively distinguishing between young and mature plaque, reducing interference from dental hard tissue and fillings.
Implementation Method 1
the nonlinearity of one or more of the absorption and fluorescence excitation spectrum of plaque allows for the generation of absorption and emission harmonics
Implementation Method 2
the nonlinearity of one or more of the absorption and fluorescence excitation spectrum of plaque allows for the generation of absorption and emission harmonics
Data Source
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AI summary
A plaque detection apparatus (70) and method make use of an excitation source (72), a light detector (74) and a controller (76). The excitation source (72) outputs wavelength modulated light (λex) to an evaluation site (80) that has a periodically changing wavelength centered around a wavelength corresponding to a non-linearity in an absorption and/or a fluorescence excitation spectrum for a chosen plaque. The chosen plaque exhibits spectral characteristics different from non-chosen plaque and/or interfering species. The light detector (74) detects light (λsite) (84) received from the evaluation site (80), including site reflected light (λrefl) and/or site emitted light (λem)- The controller (76) operatively couples to the excitation source (72) and the light detector (74) for controlling the excitation source to output the wavelength modulated light and detecting plaque as a function of the detected light (λsite) and at least one higher harmonic of the wavelength modulation frequency.