A woman who posed as a dentist in Basildon and Thurrock Hospital has admitted carrying out work on hospital patients despite not being qualified.
Vinisha Sharia, 37, of Willenhall, West Midlands, admitted forging qualifications and earning £230,000 by deception reports the BBC.
She wrongly claimed to have a degree from the Sri Guru Ram Das institute in India, Wolverhampton Crown Court heard.
The case was adjourned for pre-sentence reports but the judge warned her there was a high chance of a prison sentence.
Sharma admitted one count of using a forged degree and four counts of obtaining a pecuniary advantage.
She also admitted a charge of fraud by false representation.
The court heard she had studied dentistry during the early 1990s but failed her exams.
In 2000, she applied for membership of the General Dental Council using the degree she claimed to have got in India.
The court head she had worked for nine years at six NHS trusts carrying out a wide range of duties, including minor surgery.
She was charged after an investigation by the NHS Counter Fraud Service.
Sentencing will take place during the week beginning 18 October.