Dental surgeons are calling for the government in England to encourage all schools to go sugar-free in a bid to combat tooth decay.
They say it is essential to cut sugar in school meals to tackle a condition affecting a quarter of five-year-olds.
Dentists also want more supervised teeth-brushing in schools and guidelines on healthy packed lunches.
Before leaving Downing Street, Prime Minister Theresa May announced plans to improve children's oral health.
Her government produced a green paper on tackling the causes of preventable ill health.
But the Faculty of Dental Surgery says that while progress has been made, more needs to be done.
Tooth decay is the leading cause of hospital admissions among five-to-nine-year-olds over the last three years, its report says.
Yet figures show that 41% of under-18s didn't visit an NHS dentist last year.
And the figure is 77% among children aged between one and two, despite guidance that all children should see a dentist at least once a year.
The faculty has produced a report containing 12 recommendations to try to cut down on cases of tooth decay.
- all schools in England to introduce supervised teeth-brushing schemes, as exist in Scotland and Wales, before 2022
- all schools to become "sugar-free"
- extending the soft-drinks levy to include sugary dairy drinks
- limiting advertising and promotions for high-sugar products
- reducing the sugar content of commercial baby foods
Prof Michael Escudier, dean of the Faculty of Dental Surgery at the Royal College of Surgeons of England, said: "It is incredibly worrying that levels of tooth decay among children in England remain so high - especially when you consider that it is almost entirely preventable through simple steps, such as brushing twice a day with appropriate-strength fluoride toothpaste, visiting the dentist regularly and reducing sugar consumption."
He added: "The scourge of child dental decay cannot be allowed to continue.
"Everyone needs to play their part in ensuring our children have healthy, happy teeth."
The Faculty of Dental Surgery said a campaign to remind people how often to take their children to a dentist, and the availability of free NHS dental care, was needed.
The British Dental Association said many parents were not aware that dental check-ups and treatment for under-18s were free.
And it called for investment in a national oral health programme for children in England, matching those already set up in Scotland and Wales, to help children develop good habits from an early age.
BDA chairman Mick Armstrong said: "It's a scandal that tooth decay remains the number one reason for child hospital admissions.
"We will not see real progress until ministers start going further and faster on prevention."
The Department for Education said schools in England had to provide pupils with a nutritious school meal and restrict foods high in sugar from lunch options.
A spokesperson said: "This includes a ban on drinks with added sugar, chocolate or sweets in school meals and vending machines.
"Additionally, we are in the process of updating these standards to further reduce the sugar content of school meals."