A patients' group says it is concerned over a lack of access to NHS dentists in South Gloucestershire after two surgeries turned private.
Frampton and Flaxpits surgeries say NHS targets can not be reached without putting patients and staff at risk. and they must go private to survive.
Vicky Marriott, of Healthwatch, an independent statutory body representing patients, said not having an option to have NHS care was a "real concern".
In a letter to patients, Dr Dimitri Haddjeri, dentist at Framptom and Flaxpits surgeries, said "target-driven, high-volume dentistry" was "not fit fo