In the UK, around a third of British children have tooth decay. Just among the under-fives, it's a quarter - a figure that rises significantly in the most deprived areas. Tooth decay can cause speech development issues, embarrassment for children and in 2023, 15 million school days were missed due to tooth pain or treatment. There’s a financial cost too – in 2023 in England alone tooth extractions under a general anaesthetic cost the NHS £41 million. And it's totally preventable. So, how can we stop teeth rotting in the first place? One way initiative announced by the new Labour government is to expand supervised toothbrushing sessions to more children. We find out how these work with Oral Health Team Lead Helen Bullingham who supports nurseries and schools in East Sussex to deliver these programmes. But what about the evidence to support this intervention? Zoe Marshman, Professor of Dental Public Health at University of Sheffield, explains her findings and dental hygienist and researcher at King's College London Dr Claire McCarthy describes what parents should be doing, in an ideal world, at home. And finally, what role does sugar play and how can we get consumption down? Dr Nina Rogers from the Population Health Innovation Lab at the London School of Hygiene & Tropical Medicine explains her findings into the impact of the Sugar Drinks Industry Levy introduced in 2018. Presenter: James Gallagher Producers: Hannah Robins Content Editor: Holly Squire Inside Health is a BBC Wales & West production for Radio 4, produced in partnership with The Open University.