Bi-frequency dental examination for early plaque detection

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Solution Overview

Problem

Traditional methods for detecting dental plaque and carious lesions struggle to differentiate between young plaque and clean surfaces due to low contrast, with only older plaque being readily detectable, limiting early detection sensitivity and specificity.

Innovation Solution

A system using lighting elements with peak wavelengths of 405 nm and 450 nm, capturing images through a long-pass filter, and manipulating these images to create a new output based on red and green channel ratios, allowing for enhanced detection of young plaque fluorescence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional QLF technique with 405nm excitation light is used, then older plaque (3-5 days) can be readily detected, but young plaque (less than 3 days) cannot be distinguished due to low contrast

Engineering Contradiction:
Improvedetection sensitivityVSAvoidinformation about young plaque
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The detection process is segmented into multiple excitation wavelengths (405nm and 450nm) with separate image captures. Each wavelength provides complementary information: 405nm detects older plaque while 450nm enhances young plaque visibility. The segmented images are then processed independently before being combined through ratio calculations to achieve comprehensive plaque detection across all ages.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention adds a spectral dimension to the detection system by introducing a second excitation wavelength (450nm) in addition to the traditional 405nm. This spectral dimensionality allows differentiation of plaque at different developmental stages by exploiting the distinct fluorescence responses of young versus mature plaque to different wavelengths, thereby recovering information about young plaque that was previously lost.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If single wavelength (405nm) excitation is used, then device complexity is low, but detection specificity for different plaque types is insufficient

Engineering Contradiction:
Improvedetection specificityVSAvoidlighting and filtering system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention changes the excitation wavelength parameter from a single value (405nm) to multiple discrete values (405nm and 450nm). This parameter change enables specific detection of different plaque types by exploiting their differential fluorescence responses at different wavelengths, thereby improving detection specificity while managing device complexity through the use of discrete LED sources and digital image processing.

Inventive Principle:
Principle #35Parameter changes

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

The system achieves higher sensitivity and specificity in detecting young plaque, enabling earlier and more accurate differentiation between plaque-covered and clean dental surfaces.

Implementation Method 1

the fluorescence of porphyrins produced by active bacteria in the intra-oral environment can be imaged as these appear with a red color compared to sound teeth by a camera or by the eye

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP3442397B1Bi-frequency dental examination
Publication Date: 2021.06.09 INSPEKTOR RES SYST
  • EP3442397B1 patent drawingFigure 1
  • EP3442397B1 patent drawingFigure 2
  • EP3442397B1 patent drawing

AI summary

A system and a method for improving visibility of newly decaying or carious tissue are described. Light having a lower peak wavelength (such as 405 nm) illuminates dental tissue, and an image is captured. Light having a higher peak wavelength (such as 450 nm) then illuminates the same dental tissue, and a second image is captured. The images are aligned, and an output image is created based on at least one of the first image and the second image, modified in certain areas as a function of the relationships between the red values of the first image (R1) and the second image (R2) at that location and the green values of the first image (G1) and the second image (G2) at that location. The function may use the ratios R2:R1 and G1:G2, such as a function of the product of those ratios, to determine the color adjustment that is applied.