Dentists are overcharging their patients by up to £109 million a year, according to the new data from the Conservatives.
The Conservatives claim dentists are exploiting an incentive loophole that lets them call patients back too often and splitting courses of treatment unnecessarily, allowing them to charge for the same treatment more than once.
NHS guidance states that no patient should be called back to their dentist for a check-up within three months and necessary treatment should not be divided over this period.
The findings are based on figures provided by every primary care trust in England and reveal that had the guidelines been followed up to 6.5 million slots could have been freed up for people lacking an NHS dentist .
The Tories said the extra capacity could have been used to provide one course of treatment for most of the 7.4 million patients who have been unable to find an NHS dentist since the new contract was introduced in April 2006.
Furthermore, existing patients could have saved a combined £109 million in unnecessary charges - equal to 23 per cent of the £475 million dental patients in England pay in charges every year.
Shadow health secretary Andrew Lansley said: "The blame here lies with Labour's botched dental contract, which incentivises dentists to increase the number of charges to patients and has led to such drastic cuts in the number of people being able to find an NHS dentist ."
"At the moment we're all losing out - those who do have a dentist are paying wrongful charges, and those who don't are being blocked from finding one because there aren't enough appointments left."
"The Government urgently needs to admit that the dental contract has been a monumental failure, get a grip and put an end to these practices immediately," he added.
