It carried out a study of NHS and private dentistry in the UK.
The OFT found that about 500,000 people a year were given the wrong information about their treatment options.
Overall, however, the OFT found that most patients were satisfied with their dentists' services.
In response to the report Health Minister Lord Howe said: "We welcome this study, which has found that the vast majority of patients are happy with their dental treatment - and that the vast majority of dentists behave ethically.
"However, denying patients care on the basis of misinformation is a very serious matter - any dentist that does this risks breaching their contract and we would expect the local NHS to take action."
The OFT discovered several important problems with the availability of dentists' services and the choices for patients.
The regulator concluded that the supply of dentistry in the UK was in need of urgent reform.
"Our study has raised significant concerns about the UK dentistry market which need to be tackled quickly in the interest of patients," said John Fingleton, the OFT's chief executive.
"All too often patients lack access to the information they need, for example when choosing a dentist or when getting dental treatment.
"We also unearthed evidence that some patients may be receiving deliberately inaccurate information about their entitlement to NHS dental treatment, and we expect to see robust action taken against such potential misconduct by dentists," he added.
Source : bbc.co.uk