Toothbrush Head Filament Color Change for Replacement Timing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Toothbrushes are often not replaced regularly, despite recommendations for replacement after about three months of use, leading to diminished effectiveness in maintaining oral hygiene due to wear of the filaments.

Innovation Solution

Incorporation of colored filaments with time-controlled color changing properties in the toothbrush head, which change color from an initial to a second color within a predefined time period, providing a visual signal for replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If users continue using toothbrushes beyond the recommended replacement period, then the toothbrush structure remains intact and can continue cleaning, but the filament wear increases dramatically reducing cleaning effectiveness and potentially damaging teeth and gums

Engineering Contradiction:
Improvetoothbrush usage durationVSAvoidcleaning effectiveness
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent applies color-changing filaments that transition from an initial color to a second color after a predetermined period of use (e.g., 8-12 weeks). This visual color change provides a clear signal to users that the toothbrush filaments have worn out and the toothbrush should be replaced, thereby maintaining cleaning effectiveness and preventing oral health damage.

Inventive Principle:
Principle #32Color changes

2Loss of time

If users are educated to monitor and assess toothbrush wear condition, then replacement timing can be optimized, but user compliance remains low due to the burden of continuous monitoring and memory requirements

Engineering Contradiction:
Improvetime for monitoring toothbrush conditionVSAvoiduser compliance with replacement schedule
Core Design Contradiction:
Loss of timeVSEase of operation

Solution Approach 1:

The toothbrush performs self-monitoring through the color-changing filaments that automatically indicate wear status without requiring user intervention. The filaments change color based on their own wear progression, eliminating the need for users to actively monitor or remember replacement schedules, thereby significantly improving compliance.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The color-changing filaments provide continuous visual feedback to users about the actual wear condition of the toothbrush. This immediate feedback mechanism replaces the need for users to rely on memory or manual tracking, making the replacement decision objective and easy to understand.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If the toothbrush provides clear wear indication signals, then user compliance with replacement schedules increases, but the device complexity increases due to incorporation of special filaments with time-controlled color changing properties

Engineering Contradiction:
Improveuser compliance with replacement scheduleVSAvoidtoothbrush structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent incorporates filaments with time-controlled color changing properties that automatically indicate wear status. While this adds some complexity to the toothbrush structure, the solution is integrated into the existing filament framework, using the filaments themselves as both cleaning elements and indicators, rather than adding separate monitoring systems.

Inventive Principle:
Principle #32Color 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 color change effectively signals the need for replacement, significantly increasing user compliance with recommended replacement schedules, thereby maintaining oral hygiene.

Implementation Method 1

both types having time-controlled color changing properties so that each of the first and second type of filament changes its color from an initial color to a second color within a pre-defined time period

Methodology Applied
Scientific EffectTime-controlled color changing properties: Thermochromism

Data Source

PatentEP4652895A1Head for an oral care implement and oral care implement
Publication Date: 2025.11.26 PROCTER & GAMBLE CO
  • EP4652895A1 patent drawingFigure 1~2
  • EP4652895A1 patent drawingFigure 3~4
  • EP4652895A1 patent drawingFigure 5~6

AI summary

A head for an oral care implement comprises a number of colored filaments of different types. The filaments extend from a mounting surface of the head and are grouped together to define an initial color pattern. The number of colored filaments comprise at least a first type of filament having time-controlled color changing properties and a second type of filament having time-controlled color changing properties, so that each of the first and second type of filament changes its color from an initial color to a second color within a pre-defined time period. The initial color of the first type of filament is different from the initial color of the second type of filament. The second color of the first type of filament and the second color of the second type of filament are substantially the same, preferably substantially white, grey and/or translucent. The second color of the first and second type of filament define a second color pattern. The initial color pattern changes to the second color pattern after the head is used over about 240 minutes to about 360 minutes, by applying a brushing force from about 0.5 N to about 2.5 N.