Plaque Detection via Fluorescence Ratio and Difference
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Solution Overview
Problem
Existing plaque detecting devices require users to find a tooth surface without biological deposits for calibration, which is difficult and time-consuming, and do not allow for simple determination of plaque presence.
Innovation Solution
A plaque detecting device that uses ultraviolet or blue excitation light to differentiate between plaque and enamel based on specific fluorescent light wavelengths, eliminating the need for calibration by determining the ratio and difference of spectral components, allowing for straightforward identification of plaque presence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a plaque detecting device compares fluorescent light intensity from a tooth surface to a reference value obtained from a tooth surface without biological deposits, then plaque detection can be performed, but the device requires a time-consuming calibration operation to find and save a reference tooth surface
Solution Approach 1:
The device performs self-calibration by automatically identifying enamel regions and using them as reference points without requiring user intervention to find a clean tooth surface. The control unit automatically separates enamel fluorescence from plaque fluorescence signals and establishes reference values during the measurement process itself.
Solution Approach 2:
The device performs preliminary separation and identification of enamel and plaque fluorescent signals before the actual plaque quantification measurement. By pre-identifying enamel regions and establishing reference values in advance, the device eliminates the need for separate calibration operations before use.
2Device complexity
If a plaque detecting device uses a single wavelength measurement to detect plaque, then the device structure is simple, but the device cannot reliably distinguish between plaque and other substances like enamel
Solution Approach 1:
The device segments the fluorescent light signal into different wavelength components, with first light receiving units detecting plaque-specific wavelengths (600-700nm) and second light receiving units detecting enamel-specific wavelengths (450-550nm). This spectral segmentation enables reliable differentiation between plaque and enamel without requiring complex additional sensors.
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 users to determine plaque presence without calibration, improving accuracy and simplifying the operation process, allowing for plaque detection during tooth brushing with a toothbrush integrated with the device.
Implementation Method 1
a plaque detecting device which irradiates light onto the surface of a tooth and determines the presence or absence of plaque based on fluorescent light coming from the tooth surface or plaque
Implementation Method 2
said first light receiving unit extracts, from said radiated light, a spectral component of a first wavelength region having a predetermined lower limit wavelength and including the wavelength range of fluorescent light specific to plaque
Implementation Method 3
said second light receiving unit extracts, from said radiated light, a spectral component of a second wavelength region having a predetermined lower limit wavelength lower than the lower limit wavelength of said first wavelength region and including the wavelength range of fluorescent light specific to enamel
Data Source
AI summary
The plaque detecting device of the present invention comprises a light emitting unit (450) which irradiates ultraviolet or blue excitation light (L) toward the tooth surface (99a), and a first and second light receiving units (402) which receive radiated light (L′) from the tooth surface (99a). The first light receiving unit extracts the spectral component of a first wavelength region including the wavelength range of fluorescent light specific to plaque from the radiated light (L′), and obtains a first output value corresponding to the intensity of that spectral component. The second light receiving unit extracts, from the radiated light (L′), the spectral component of a second wavelength region containing the wavelength range of the fluorescent light specific to enamel and having a predetermined lower limit wavelength below the lower limit wavelength of the first wavelength region, and obtains a second output value corresponding to the intensity of this spectral component. Determination of the relative magnitude of the ratio between the first output value and the second output value as compared to a first threshold value is performed. Determination of the relative magnitude of the difference between the first output value and the second output value as compared to a second threshold value is performed.