Of the 2,726 contracts between primary care trusts and dentists signed in dispute, 396 have yet to be resolved, the figures reveal.
In April 2006 a total of 8,377 new-look dental contracts were signed as the government attempted to improve NHS dentistry.
British Dental Association chief executive Peter Ward said: 'These figures are bad news for dentists and patients alike.
'A full year after the introduction of the new contract, nearly 400 disputed contracts still haven't been resolved. This adds up to continuing uncertainty for NHS dentistry.
'Tony Blair's pledge that everybody who wanted to access an NHS dentist would be able to do so has not been fulfilled.
'It is clear that urgent action is required to address the problems with the government's reforms.'
A Department of Health spokesperson said: 'Around a third of contracts were originally signed in dispute. Around 87 per cent of these have now been resolved and the overwhelming majority, 99.4 per cent, have ended with the contractor staying with the NHS.'