Dentist Desmond D'Mello: Patient hygiene recall widens
Thousands of letters are to be sent to homes to try and track down patients of a dentist being investigated for poor hygiene.
Tests have already been carried out on 4,000 people as part of its inquiry into Nottinghamshire dentist Desmond D'Mello, at a cost of £500,000.
He was filmed failing to change gloves or instruments between patients.
NHS England medical director Doug Black said this was a "further push" for more people to come forward.
The former patients were said to be at a low risk of infection from blood-borne diseases, such as hepatitis and HIV.
Last month, NHS England said it was not sending letters because it would have had to write to all houses in the county because of an incomplete and inaccurate database at an estimated cost of £300,000.
It decided an announcement through the media was a more effective way of contacting patients.
But earlier, Dr Black said a general letter would be sent to addresses in the Arnold and Daybrook area where a patient had previously been registered.
He said 4,000 responses so far was "good".
"The local and national profile this has had means there's no doubt the message has got out there," he said.
"This additional exercise is a further push to see if we can improve on that figure."
Patients' data is not owned by the NHS, Dr Black said, but by the data provider - in this case Southern Dental, which now runs the Daybrook Dental Practice.
As a result the NHS can only write to addresses held on the former practice's database, which he said was "inaccurate".
"Of course it's frustrating. Had we been able to say we have a verified, accurate list of the patients involved, we may have taken a different course," Dr Black added.
Mr D'Mello, who ran the practice, was suspended after he was covertly filmed appearing to fail to wash his hands and sterilise equipment between appointments.