Dentists say decay is preventable by regular brushing and check-ups
Nearly 30,000 children a year attend hospital to have teeth pulled or be treated for decay, research has shown.
Researchers who analysed hospital data said it was "worrying" that the number of under-17s hospitalised for dental treatment had been rising since 1997.
They found children from poor areas were twice as likely to need treatment as those from more affluent families.
Experts said the findings, published in the British Dental Journal, highlighted a major public health issue.
It has led to criticism of Labour's policy relating to NHS dentists and calls by some for compulsory water fluoridation.
The data revealed there were 517,885 individual courses of dental treatment in NHS hospitals for children up to the age of 17 between 1997 and 2006.
The total number of children needing treatment was 470,113 and 80% of admissions involved extraction - in two-thirds of cases because of tooth decay.
The peak age for children needing teeth taken out was five.
Prof David Moles, who led the study at Plymouth's Peninsula Dental School, said yearly rises in hospital admissions had come despite rates of tooth decay and infection remaining steady.
The reasons for this would have to be identified "in order to cut the number of admissions, improve dental care for children and ultimately reduce the financial burden to the NHS", he said.
Dr Paul Ashley, head of paediatric dentistry at University College London's Eastman Dental Institute, was the second author of the study.
He said: "Two aspects of the study are particularly worrying - the rise in the number of general anaesthetics being given to children, and the widening gulf in dental health between social classes."
He said general anaesthetics could be fatal to children.
Tooth decay is preventable through regular brushing and check-ups and Peter Bateman, chairman of the British Dental Association's salaried dentists committee, said: "It is a tragedy that social class remains such an accurate predictor of oral health.
"Water fluoridation, as the long-standing scheme in the West Midlands illustrates, has great potential to address this divide."
'Lack of access'
Liberal Democrat health spokesman, Norman Lamb, criticised the "appalling lack of access" to NHS dentists and called for a "radical overhaul" of the system.
He told BBC Radio 5Live: "One of the possible causes [of poor child dental health] is that children are not going to the dentist enough.
"We hear constantly about problems in accessing NHS dentists. It really demonstrates a failure of government policy that the situation is getting worse, not better."
Mr Lamb acknowledge that the research was based on figures pre-dating the 2006 introduction of new contracts for NHS dentists, which aimed to widen access.
But he said: "What we've seen since is the position getting even worse."
A Department of Health spokesman said the study's findings had been influenced by changes in 2001 to ensure anaesthesia was given in hospitals - rather than dental surgeries - for safety reasons.
"There has been no increase in tooth decay in the period covered, which pre-dates the new dental contract," the spokesman said.
"Preventative oral healthcare has actually improved substantially thanks to the new dental contract.
"Recent statistics from the World Health Organisation show that our 12-year olds have the healthiest teeth in Europe."
The government advised the NHS to consider introducing water fluoridation in some areas, where it was supported by communities, to address disparities in oral health, he added.