New contracts for NHS dentists were introduced in 2006
Dentists in England are playing the system to maximise their profits, the government believes.
An analysis of NHS paperwork suggests dentists are recalling healthy patients for check-ups and dividing courses of treatment unnecessarily.
Chief dental officer Barry Cockroft is talking to local health bosses, believing a tenth of appointments could be freed up if the problem was solved.
But dentists said there was no evidence it was happening.
The Department of Health believes the tactic has become widespread since the introduction of a new contract in 2006.
The deal was drawn up to reform the so-called "drill and fill" culture by letting dentists spend more time with their patients.
The changes also saw NHS treatments divided into four bands to streamline the charging system - NHS work is heavily subsidised but most adults still pay something towards their care.
It means that dentists can claim twice as much by spreading treatments across different appointments or calling patients back for unnecessary check-ups.
Officials have compared NHS returns by dentists, which give each individual patient a code, to see how many people are attending repeat appointments.
The analysis suggested that as many as 800,000 appointments - a tenth of the regular dental workload - could be freed up if the practice was stopped.
It comes as earnings have risen under the new contract.
Average earnings stood at just over £96,000 in the first year of the deal - a rise from £87,000 from the year before.
For the top-earning dentists who own their own practice income rose by a third to £172,494.
A Department of Health spokesman said dentists had to change the way they worked.
"Many patients have been seeing their dentist at six month intervals for years as a matter of routine, but there is no evidence to support this as clinically necessary."
But Peter Ward, chief executive of the British Dental Association, the trade union for dentists, said the organisation had seen no evidence this had been happening.
"The interval between patients being recalled by their NHS dentist is, according to guidelines, a matter for the practitioner's clinical judgement in consultation with the patient."