Patients seeking help for tooth problems on the NHS are being "failed", leading dentists have said.
The British Dental Association (BDA) said dentists are bound by trying to achieve "senseless targets" which means they are forced to provide more curative treatments than preventive care.
Part of the way NHS dentists get paid depends on them hitting targets for a number of measures, but the BDA said the payment system is "failing patients in the most need".
A poll conducted by the BDA found that 93% of dentists said the targets were standing in the way of treating patients in most need.
Of the 1,245 NHS dentists in England and Wales surveyed, 83% said the current system is holding them back from performing preventive work on patients.
The BDA is calling on the Prime Minister to ensure that a new contract is reformed and not "wedded to models based on discredited activity targets".
Henrik Overgaard-Nielsen, chairman of the BDA's General Dental Practice Committee, said: "The survey shows that those in most need have become the least welcome in NHS dentistry, thanks to a system that puts Government targets before patient care.
"We are seeing the results of a conveyor belt model of provision that has left dentists without the time or the freedom to deliver the treatment their patients require.
"NHS dentists are still being forced to chase targets for curative treatment, rather than provide vital preventive care.
"This topsy-turvy system means dentists are paid the same for doing one filling or 14, and are routinely subsidising care for high-needs patients out of their own pockets.
"We receive financial penalties when we don't hit targets, receive no compensation when we exceed them, and have no scope to take on new NHS patients, even when we have capacity.
"Sadly, government has yet to show it's willing to let go of these senseless targets. A watered down version of this failed contract isn't progress. We call on ministers to live up to their rhetoric and put prevention first."
A Department of Health spokeswoman said: "We agree with the BDA that the dental contract needs an update - that is why we are radically changing NHS dentistry, so that dentists will be paid for keeping the nation's teeth healthy, as well as treating problems as they arise.
"We are working with the BDA to make sure that the new contract allows dentists to give patients the best possible care."