Dentist Donald Macfarlane allegedly failed to report the ulcer which grew to be at least three centimetres long.
The 54-year-old patient saw the dentist three times in early 2010, as the ulcer got bigger and bigger, it is alleged.
But he died eight months later after an invasive skin cancer was found.
A General Dental Council (GDC) hearing into Dr Macfarlane’s conduct began today (tue), and the dentist could be struck off of it is found he has committed misconduct.
Dr Macfarlane lives in Glasgow and works as a tutor at a “teach and treat” dental clinic in Kilmarnock, East Ayrshire.
The dentist’s patient, referred to only as “Patient A”, smoked up to 15 cigarettes a day and drank 14 units of alcohol a week, the GDC charges say.
Dr Macfarlane first saw the patient on 11 February 2010 and he was “complaining of pain in the lower right [part of his mouth] for approximately a week,” the charges say.
The charges state that an ulcer measuring about 9mm across by 5mm high was diagnosed on the lower right lining of the cheeks and inside of the lips.
They allege the dentist “failed to ensure that Patient A was provided with smoking cessation advice” and “failed to ensure that Patient A was invited to return for a review should the ulcer persist for more than 3 weeks”.
At another appointment a month later, the ulcer was still present but Dr Macfarlane continued to take no action, it is claimed.
The charges say he “failed to ensure that the patient was urgently referred for specialist opinion”.
Patient A returned to Macfarlane’s clinic at the “teach and treat” dental centre in Kilmarnock on 28 April, the GDC says.
They say: “It was noted that the ulcer had increased in size and was now measuring about 15mm across by 7mm in height.”
Again, Dr Macfarlane did not refer the patient for an urgent assessment, the GDC says.
The charges also say the patient eventually went to see another dentist.
“On 15 May 2010 Patient A was seen by another dentist with regards to the ulcer and arrangements were made for a biopsy.”
Patient A returned to Dr Macfarlane on 8 June, and the GDC says the ulcer had now tripled in size.
The charges say: “Patient A informed you that he had sought a second opinion in respect of the ulcer and a biopsy had been performed.
“It was noted that the ulcer had further increased in size now measuring at least 30mm long.”
The GDC goes on to say “On 14 June 2010 an invasive squamous cell carcinoma was confirmed” and “Patient A died on 13 February 2011.”
The hearing, which is held in London and chaired by Kevin Moore, is due to continue until later this week.
Dr Macfarlane was unavailable for comment.