Ultrasonic Toothbrush Head with Asymmetric Bristle Rows for Braces

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Solution Overview

Problem

Conventional sonic and ultrasonic toothbrushes fail to effectively clean the areas around the base of dental braces, particularly the mesiodistal areas below the arch and lateral tooth sections due to the rotating movement and shape of the brush head, which prevents bristles from making contact with the bracket or tooth surfaces.

Innovation Solution

A brush head design with a reduced inner row of bristle tufts that can easily slip over archwires and brackets, combined with longer, inclined outer tufts that reach the tooth surface, ensuring thorough cleaning around the bracket base, utilizing a piezoelectric ultrasonic generator for vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the brush head has a conventional shape with uniformly long bristles arranged in parallel rows, then the brush head structure is simple and easy to manufacture, but the bristles cannot make contact with the bracket or tooth surfaces in the mesiodistal areas below the arch and lateral tooth sections, resulting in insufficient cleaning power

Engineering Contradiction:
Improvebrush head structure simplicityVSAvoidcleaning effectiveness around bracket base
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by creating different bristle configurations in different regions of the brush head. The inner rows have shorter bristles that can slip under the archwire to clean the bracket base, while outer rows have longer bristles for cleaning accessible tooth surfaces. This regional differentiation ensures that each area of the brush head is optimized for its specific cleaning task, resolving the contradiction between manufacturing simplicity and cleaning effectiveness.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs asymmetry by arranging bristle rows at different lengths and orientations rather than using a symmetric, uniform configuration. The inner bristle rows are shorter and positioned to access the bracket base area, while outer rows are longer and angled to reach lateral tooth surfaces. This asymmetric design allows the brush head to effectively clean previously inaccessible areas without significantly complicating the manufacturing process.

Inventive Principle:
Principle #4Asymmetry

2Adaptability or versatility

If the brush head rotates during cleaning, then the brush head can cover multiple tooth surfaces, but the bristles fail to reach the bracket corners and mesiodistal areas below the arch, leaving plaque-free areas incomplete

Engineering Contradiction:
Improvebrush head coverage areaVSAvoidcontact with bracket corners
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies dimensionality change by adding a vertical component to the bristle arrangement. The inner rows of shorter bristles are positioned to extend vertically underneath the archwire, creating a three-dimensional cleaning capability that complements the horizontal rotation of the brush head. This multi-dimensional bristle configuration ensures that rotating the brush head brings different angled surfaces into contact with various tooth and bracket areas, achieving complete coverage of previously inaccessible regions.

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

3Reliability

If longer bristles are used to reach the tooth surface, then cleaning of lateral tooth sections improves, but the bristles may interlock and prevent efficient ultrasound transmission

Engineering Contradiction:
Improvecleaning of lateral tooth sectionsVSAvoidultrasound transmission efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent resolves this contradiction by applying local quality through spatially differentiated bristle lengths. Longer bristles are positioned only in outer rows where they can reach lateral tooth surfaces without interfering with the ultrasonic transmission path. The inner rows maintain shorter bristles that allow efficient ultrasound transmission while still providing cleaning action through their vibration. This localized optimization ensures that longer bristles provide extended reach where needed without causing bristle interlocking that would impede ultrasound energy transmission.

Inventive Principle:
Principle #3Local quality

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 design allows for effective cleaning of dental braces by ensuring direct contact with the bracket corners and tooth surfaces, improving hygiene by preventing bristle interlocking and maintaining efficient ultrasound transmission.

Implementation Method 1

a piezoelectric ultrasonic generator (14) integrated into the base body (4) causing the bristle tufts (10) to vibrate

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

an ultrasonic transducer integrated into the brush head causes the flexible bristles, which are usually combined into bristle tufts, to oscillate at high frequencies

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentEP2782477B1Brush head for a sonic or ultrasonic toothbrush and toothbrush
Publication Date: 2020.05.06 EMAG AG
  • EP2782477B1 patent drawingFigure 1
  • EP2782477B1 patent drawingFigure 2
  • EP2782477B1 patent drawingFigure 3

AI summary

The invention relates to a brush head with an integrated ultrasonic transducer and with a plurality of bristle tufts that are arranged on a baseplate and can be caused to vibrate by the ultrasonic transducer during operation, wherein the bristle tufts are arranged in a plurality of substantially parallel rows aligned symmetrically relative to a central longitudinal axis or central plane of the baseplate, wherein a first row and at least one second row are provided in the transverse direction as viewed from the central longitudinal axis or central plane, and wherein all bristle tufts of a row are the same length. Such a brush head is to be improved so that a particularly thorough and reliable cleaning of the teeth is possible when a fixedly installed brace is present. For this purpose, the bristle tufts of the second row are designed according to the invention to be longer than the bristle tufts of the first row.