Two Canadian students have developed a colour-changing toothpaste designed to make toothbrushing easier for children to understand. Ella Zhang and Gillian Leung, students at Havergal College in Canada, created ‘ToothTint’ as a school project that uses a natural pigment to change colour in response to conditions inside the mouth. The idea is intended to give children a visual signal while brushing, helping them understand whether they have brushed for long enough instead of relying only on a timer.According to the ‘Blue Ocean Student Entrepreneur Competition,’ the project was recognised among its 2026 Top 30 entries. ToothTint addresses a familiar challenge that ‘children may rush through brushing because the activity offers little immediate feedback.’ However, colour-changing toothpaste is not an entirely new concept. ‘Crest’ also produces a toothpaste that changes from blue to pink during brushing, showing how visual cues can encourage children to brush for longer.
Canadian students’ colour-changing toothpaste helps children brush properly
For Ella Zhang and Gillian Leung, the challenge was to make brushing less of a guessing game. According to the Blue Ocean Student Entrepreneur Competition, their ToothTint toothpaste changes colour because of ‘anthocyanins,’ natural pigments that react to different pH environments in the mouth. This provides children with visual feedback as they brush. Blue Ocean describes ToothTint as different from other colour-changing toothpastes because its colouring system uses anthocyanins rather than chemically based pigments. The students’ project therefore combines a practical purpose with the use of a natural colouring ingredient.
A simple school project built around an everyday problem
Their idea appeared among student-developed business concepts aimed at addressing everyday problems. The project focuses on a straightforward challenge that children may struggle to judge how long they have been brushing. Instead of relying on a clock or separate timer, ToothTint makes the toothpaste itself part of the feedback process. The changing colour adds an interactive element to the routine and could help children stay engaged while brushing.
Visual feedback makes toothbrushing more interactive
The ToothTint project shows how an everyday product can be rethought from a child’s perspective. Crest similarly presents colour-changing toothpaste as a way of making the activity more enjoyable and encouraging young children to complete a longer brushing routine. Its children’s toothpaste changes from blue to pink throughout two minutes of brushing and is designed for children aged three and above.For ToothTint’s creators, the same principle has been explored through a natural pigment that responds to conditions inside the mouth. Blue Ocean competition demonstrates that business ideas can begin by identifying problems that are broken, overlooked or difficult in everyday life. In this case, Ella Zhang and Gillian Leung focused on a common challenge in children’s oral care and developed a product-based response. Their project does not rely on a separate device; instead, it aims to turn toothpaste into a source of visual feedback.
