NHS dentistry was reformed two years ago
Almost 900,000 fewer people are now seeing an NHS dentist than before government reforms, figures show.
In the two years up to December 2007, 53.7% of the English population saw a dentist compared with 55.8% in the 24 months before the new dental contract.
Dentists warned the NHS Information Centre statistics show the 2006 reforms have failed to improve access.
But the government said new services were in place that were not yet reflected in the figures.
The NHS Information Centre report also found there is wide variation in access to dental services across England.
Among adults, the proportion who had seen a dentist in the 24 months up to December 2007, ranged from 38.9% in the South Central Strategic Health Authority area to 58.3% in the North East.
There was also a wide variation in the number of children who have access to dental services with 73.4% seeing a dentist over the same period in the north east compared with 64.8% in London.
The new dental contract, introduced in April 2006, was intended to allow dentists to spend more time with NHS patients in a bid to make the profession more attractive.
Peter Ward, chief executive of the British Dental Association, said: "These figures offer fresh evidence that the reforms have failed to achieve their stated aims.
"They've failed to improve access to care for patients and failed to allow dentists to provide the modern, preventive care they want to deliver.
"Instead, this contract encourages sporadic, episodic treatment, rather than the long-term, continuing relationships that dentists and their patients value."
Shadow health minister Mike Penning said: "These figures are yet another damning indictment of Labour's appalling management of NHS dentistry.
"The fact that over 300,000 people lost their dentist in three months alone shows just how bad things are getting."
But the government's chief dental officer, Barry Cockcroft, said expanding NHS dentistry was a priority with an extra £200 million invested this year to help strengthen existing services and open more practices.
"The Information Centre access figures released today do not reflect the new services that are opening all the time.
"Rather, the figures are retrospective and include the temporary decrease in access which occurred following the transition to the new system in 2006.
"It will take time before the current access situation is reflected in such figures."