Ronnie Barogiannis, 44, treated hundreds of people at the clinic he worked at in Cottingham, East Yorkshire, despite not being allowed to practice in the UK.
Among his patients was a woman who had the wrong tooth removed, and another who suffered a severe infection following root canal treatment.
According to a report in the Guardian, a number are now planning to take legal action.
Described as “devious and utterly incompetent”, during 2013 and 2014 Barogiannis had around 600 patients and earned almost £50,000.
Hull Crown Court heard he had previously been prosecuted for working illegally in Aberdeen, but then stole the name and registration details of a Greek colleague to land the job.
He had obtained a degree in dentistry in Sweden in 2003, but had not been registered to practise in the UK, despite several applications.
But his web of lies began to unravel following the sale of the clinic when he accidentally revealed his real name in an email his new employers.
He was arrested and bailed, but fled the country to Sweden where he was caught working in March and extradited back to the UK.
Barogiannis pleaded guilty to fraud and four counts of assault occasioning actual bodily harm when he appeared at court.
Jailing him, Judge Jeremy Richardson QC said: “This sort of case – although an isolated example of serious criminal conduct by a devious, profoundly dishonest and utterly incompetent dentist – inevitably affects the confidence of the public in dental surgeons.
“You have damaged the standing of your profession, but I doubt it will be your profession for much longer. You have caused significant harm to your victims by the crimes you committed. You are a disgrace to your profession.”
Speaking after the sentencing, Detective Chief Inspector, Lucy Khan, said: “I hope that the jail sentence will prevent others from operating as bogus medical professionals.”
A spokesman for the practice, now called Oasis Dental Care, said: “Having identified and dismissed Barogiannis, Oasis wrote to all patients seen by Barogiannis and offered either an examination plus any necessary remedial work at no cost to the patient, or a refund of any fees paid to Barogiannis if patients preferred to seek dental care elsewhere.”