More than 160,000 children starting primary school in England have decayed teeth, according to a new report.
Figures from Public Health England show that 23.3% of five-year-olds have dental decay.
PHE's National Dental Epidemiology Programme for England shows that, while there have been marked improvements in the proportion of youngsters who show signs of dental decay, there are still 164,000 children starting their school career with rotten teeth.
Around 17,000 of these youngsters have been forced to have decayed teeth removed.
Tooth extraction often requires a hospital stay and a child being put under general anaesthetic.
Figures from the 2017 report show that in one corner of England - Tower Hamlets in London - 7.2% of five-year-olds have undergone tooth extraction.
Across the country the average is 2.4%.
But there are wide regional variations - in Yorkshire and the Humber 4.1% of children have had a tooth extraction due to dental decay, while in the East of England this figure is 1.3%.
But there have been improvements in the proportion of youngsters suffering dental decay in the last decade - in 2008, 69.1% of five-year-olds showed no obvious signs of dental decay. This rose to 76.7% in 2017.
However, among the 23.3% of children with some experience of obvious decay, the average number of teeth that were decayed, missing or filled was 3.4.
The PHE report reveals "wide variation" between regions - with children from more deprived backgrounds more likely to experience decay.
"Analysis shows that, while dental decay levels are reducing, and there are signs that inequalities are beginning to reduce, the inequalities gap remains unacceptably high," the authors wrote.
Commenting on the figures, Izzi Seccombe, chairwoman of the Local Government Association's Community Wellbeing Board, said: "Tooth decay is largely preventable, yet is the most common oral disease affecting children and young people.
"The findings of this survey highlight the need for urgent investment in oral health education so that parents and children understand the impact of sugar on teeth and the importance of good oral hygiene.
"Untreated dental care remains one of the most prevalent diseases affecting children and young people's ability to speak, eat, play and socialise.
"This study underlines how regular check-ups at a dentist can help prevent tooth decay and the need for hospital treatment."
NHS dental care for children is free. NHS Choices advises that youngsters should begin visiting the dentist when their first milk teeth appear. They are advised to go for regular check-ups.