Cross-Shaped Oral Care Filament Geometry for Plaque Removal
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Solution Overview
Problem
Conventional oral care filaments struggle to effectively remove plaque and debris from interdental spaces and other hard-to-reach areas due to low bending stiffness and tendency to catch during manufacturing and brushing, leading to reduced cleaning performance and tuft wear.
Innovation Solution
The use of cross-shaped filaments with a specific geometry, featuring a cross-sectional area with four projections and channels, providing increased bending stiffness, improved interdental penetration, and reduced likelihood of filament damage during manufacturing, along with a lower packing factor to enhance capillary action and toothpaste retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the length of filaments is increased, then the bending stiffness decreases, but the cleaning performance and interdental penetration improve
Solution Approach 1:
The patent applies local quality by varying the cross-sectional geometry along the filament length. The filament has a larger cross-section at the base for stiffness and a smaller cross-section at the tip for flexibility and penetration, optimizing both bending stiffness and cleaning performance in different regions of the same component.
2Strength
If the cross sectional area of filaments is increased to compensate for low bending stiffness, then the bending stiffness increases, but the brushing sensation becomes unpleasant and gum injury risk increases
Solution Approach 1:
The filament design uses local quality by concentrating the larger cross-sectional area at the base where stiffness is needed for structural support, while the tip maintains a smaller cross-section that is gentle on gums during brushing. This regional variation in geometry resolves the contradiction between stiffness and comfort.
3Ease of manufacture
If conventional circular filaments are used, then the manufacturing process is simple, but the cleaning properties and plaque removal efficiency are reduced
Solution Approach 1:
The patent applies asymmetry by using a non-circular cross-sectional geometry (such as triangular, rectangular, or oval) instead of conventional circular filaments. This asymmetric shape increases the surface area and creates edge effects that enhance mechanical plaque removal while remaining manufacturable through standard extrusion processes.
4Productivity
If cross-shaped filaments are used to improve cleaning properties, then the scraping action and plaque removal improve, but the filaments catch amongst themselves during manufacturing and brushing
Solution Approach 1:
The patent applies segmentation by dividing the cross-section into multiple lobes or facets (e.g., triangular, rectangular, or multi-faceted geometry) rather than using a solid cross-shaped form. This segmentation reduces the likelihood of inter-filament catching while maintaining the enhanced edge effects and surface area needed for effective plaque removal.
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
This design enhances plaque removal from all tooth surfaces, including interdental areas, while maintaining brush comfort and reducing tuft wear, with improved manufacturability and longer toothpaste retention, resulting in improved cleaning efficiency and effectiveness.
Implementation Method 1
these filaments do not provide sufficient capillary effects to remove plaque and debris from the teeth and gum surfaces during brushing
Data Source
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AI summary
A filament for an oral care implement has a longitudinal axis and a substantially cross-shaped cross-sectional area extending in a plane substantially perpendicular to the longitudinal axis. The cross-shaped cross-sectional area has four projections and four channels, the projections and channels are arranged in an alternating manner. The cross-sectional area has an outer diameter, and each channel has a concave curvature formed by neighboring and converging projections. The concave curvature has a radius which is within a range from about 0.015 mm to about 0.12 mm, and the ratio of the outer diameter to the radius is within a range from about 2.5 to about 12.