Patients of a dentist diagnosed with HIV are contacted in Paisley and Dumfries
Two NHS boards have contacted thousands of patients as a precaution after a dentist who treated them was found to have the HIV infection.
The former dentist practised at Kelburne Dental Surgery in Paisley until March of this year.
The dentist also provided locum Sunday emergency cover at Nithbank Hospital in Dumfries between April 2004 and 2007.
The health boards said patients had been advised of the "very slight risk" they had been exposed to the virus.
Approximately 3,000 NHS and private patients registered with the Paisley surgery had been treated by the dentist - who is no longer practising - between January 2004 and March 2013.
The majority have been contacted by letter by NHS Greater Glasgow and Clyde, but there are about 250 NHS patients and 230 private patients who have not been traced.
NHS Dumfries and Galloway has written to most of the 247 patients concerned but 14 of them no longer live in the region and have not been contacted.
A statement from the two boards said there had been 30 similar patient notification exercises in the UK in the last 25 years.
It said some 10,000 people have been tested as a result and not a single person was found to have contracted HIV as a result of medical or dental treatment.
Dr Syed Ahmed, NHSGGC consultant in public health medicine, said: "It is very rare for HIV to be passed from a health care practitioner to a patient because all work follows strict 'infection control' measures.
"These measures are designed to prevent infections like HIV being passed between people and through our investigations into this case we are confident that all appropriate infection control measures were followed by the dentist.
"Whilst we therefore think the risk is extremely low we cannot guarantee that there is no risk, so we have set up a freephone help-line where patients can ask questions and then decide if they want to have an HIV test."
Anyone who has been treated at the Kelburne Dental Surgery and has not received a letter but has concerns has been asked to contact that number.
Dr Derek Cox, director of public health for NHS Dumfries and Galloway, said: "We have identified that 247 patients were treated by this dentist.
"Of these we are unable to find addresses for 14, almost certainly because they no longer live in Dumfries and Galloway.
"If you were seen at a Sunday Emergency Dental clinic at Nithbank between April 2004 and April 2007 and have not yet received a letter, it is unlikely that you were treated by the dentist in question.
"Nevertheless, if you are concerned that you may have been missed off the list please contact the helpline."
The confidential free phone helpline is on 0800 028 2816 and will be open daily from 08:00 to 22:00 until Sunday 1 September.
HIV Scotland chief executive George Valiotis said: "No one has ever caught HIV from a healthcare worker in the UK.
"In fact the risk is so low that both the UK and Scottish governments have announced that people with HIV will soon be permitted to practice fully as dentists, midwives and surgeons.
"This new policy will reflect a fair, balanced assessment of reality: both keeping patients safe and ensuring that people living with HIV can have equal opportunity to work."