The Conservatives have claimed that NHS dental patients are being overcharged by up to £109m a year because some dentists are playing the system.
They said that analysis of primary care trust (PCT) data revealed that dentists could be bringing in patients for a second treatment unnecessarily soon to have the opportunity to charge them twice.
In October, the government said it believed dentists could be recalling healthy patients for check-ups and dividing courses of treatment unnecessarily.
Payments are currently divided up for activity so that dentists can gain twice as much by spreading treatments across multiple appointments.
The National Institute for Health and Clinical Excellence (NICE) recommends that it is not necessary to call back a dentist for a check-up within three months.
If NICE advice was adhered, the Conservatives claimed that up to 6.5 million slots could have been freed up for people lacking an NHS dentist and existing patients could have saved £109 million in unnecessary charges.
Shadow health secretary Andrew Lansley told the BBC that the results of their study were "astonishing".
He claimed that across England, 18 per cent of patients are being recalled after two months, which is the point at which they cannot be charged for an additional course of treatment.
Lansley stated: "This is rather astonishing. When we talk to dentists they know exactly why this is happening.
"I blame the government because they imposed the new dental contract which incentivises dentists to do exactly these kinds of things."
The number of people who are accessing NHS dentistry has gone down under the new contract in the last two years, he claimed. But Lansley added that in this last year alone, the amount received in charges to patients has gone up by 50 per cent.
He stated: "Fewer people seeing dentists, paying more, and the price hasn't changed. What has happened of course is that the numbers of treatments being charged for have been artificially inflated."
The shadow health secretary called on the government's system to be scrapped.
He argued: "The government said, when it was introduced, that they would undertake a review. That didn't happen. They are now having to, in a frank admission of failure, say that they are going to review the whole dental contract."
Instead, the Conservatives are suggesting that the contract should be based on the number of people registered with an NHS dentist. Dentists should be given their payment based on good dental care and maintaining good dental health for their patients, Lansley suggested.
"The principle of the National Health Service should be payment by results instead of payment for activity," he said.
"It was a fundamental mistake. We know why the government went down this path. It was because they were frightened that patient charges would go down. And so, of course they have introduced a system where patient charges have gone up."
Lansley added: "Patients are losing out. They are not getting NHS dentistry and they are paying more."
But health secretary Alan Johnson rejected calls for the contract to be scrapped.
He stated: "The question of whether dentists are fiddling the system to the tune of £109m, which is what Andrew Lansley is claiming, I think is wrong."
Johnson is asking Professor Jimmy Steele to look at the dentistry system.
He explained: "There are parts of the country where it is difficult to access NHS dentistry and I want him also to look at many other aspects of this, including this issue of whether there is too much 'gaining' in the system - of dentists actually calling people back just to make money."
Rejecting any suggestion that the new contracts had failed, he said: "I do not accept that at all.
"There is extra money going in; it is a simpler system; the proportion of patients being charged is stable at around 27 per cent."
Health minister Ann Keen called the Conservative Party's suggestion "ludicrous".
She said: "The vast majority of these patients will have been called back for a genuine clinical need such as disease management or emergency treatment.
"As we discovered earlier this year, only a small minority of dentists are recalling patients unnecessarily for treatment."
Keen claimed that the new contract made all NHS dentists accountable to their local primary care trust for quality of care.
"This means that if a dentist recalls patients unnecessarily or charges too much, local health services are able to withhold his or her funding or terminate his or her contract," she explained.
"This is one of the issues that will be investigated by the independent review team we appointed last week to advise how we can best work with the NHS to ensure good access and high quality of NHS dentistry across the country."
Dods Parliamentary Communications Ltd