Neither more nor less. Just right!

Brushing the teeth is the first step towards dental care and prevention of certain oral diseases. It is especially important among children to start getting autonomy in cleaning the teeth as early as possible. In this project, a toothbrush for children is designed. The concept supports the dynamic movements of children's hands when they brush their teeth. The toothbrush was shaped in such a way that sort of guides the hand’s positions while the child is brushing. This way, the hand gets more comfortable and the brushing action becomes more efficient. The toothbrush also has a container that stores tartar disclosure so that the children can check after clean their teeth how clean they are.

'Client' - ±0

In this project, the brand plus minus zero (±0) known for the products designed by the renowned designer Naoto Fukasawa acts as a fictitious client. The goal is to understand the brand philosophy and design a product that can fit into the company’s catalog.


±0 is a Japanese brand of household electrical appliances and sundries. The brand’s philosophy ‘Just right’ its very well represented in the designs of the brand’s products, which follow a clear influence by the minimalistic Nipponese culture. ±0 products have an intuitive language in its use, an image that is aesthetically clean and timeless, and a level of performance that convinces any person who uses ±0 products.

±0 Products

±0 design opportunities - Ideation

During two weeks period, roughly 60 concepts were sketched around the topic of household items that went from bread toaster to hairdryers or from air purifier to a stereo system. In addition, each idea needed to show a known existing problem and how it would be solved. The concepts were documented and briefly presented to the classmates were each person could select the three best concepts by giving it a star. The concept with more stars at the end would be the one further developed in the project.

Selected concept

The selected project was a toothbrush that could enable children to gain better cleaning tooth brushing habits. The main idea at this stage consisted of a product that could create awareness to the child and then motivate him/her to improve his/her oral hygiene.


Market research

Children toothbrushes tend to present vivid colors, or cartoon images. The brush is often described as soft and the head is not flexible as some toothbrush for other age groups. The body shape is often more robust which contrast with toothbrushes for adults which are slimmer. The materials used usually  are plastics (PP, TPE), rubber, and nylon, with some companies betting on more sustainable approaches by using bamboo as an alternative to plastic.

Toothbrush - concept phase

The concept chosen was the number 9 (prototypes figure). The selection of this concept combined the insights from 4 users as been the best concept to hold in different positions, hence suiting different users hands needs (i.e best ergonomics), the best concept form-function, and the best concept on look and feel.

 ±0 toothbrush set details.

 ±0 toothbrush comes in different colors. It was chosen to combine some vivid colors that references to kids preferences with the characteristic off-white color used by ±0 in many of its products.

User's journey

The user starts by pressing the timer button in the cup holder, which is preset to 2 min. After the time has passed and the teeth are brushed, the user passes the liquid in the tongue and mixes it with the saliva. If stains appears in the teeth, the user should brush the teeth again until they vanish. Finally, the user cleans the tongue, by using the tongue cleaner placed in the toothbrush head.

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