TWELVE patients suffered botched treatment at a school set up to train new dentists.

One patient was left with damage to an adjacent tooth after work was carried out and another suffered tissue damage caused by dental bleach.

And some endodontic patients - mainly people booked in for root canal treatment - ended up with perforations, the over preparation of teeth and the wrong tooth being worked on.

Inspectors from an industry watchdog have raised concerns about a visit to the Aberdeen Dental School in April 2014.

The General Dental Council report comes as Aberdeen University searches for a new director of dentistry following the departure of Professor Helen Craddock, who retired last autumn after a year in the job.

The report said: "Inspectors were concerned that a number of patients had been harmed and disappointed that the significant threats to the programme were not identified earlier by the school.

"While it was accepted that the graduating cohort's exposure to the full range of procedures had been negatively impacted by the situation with patient supply, what was seen on occasions were examples of the lowest level of care expected of a safe beginner."

A third of the 22 dental students failed to graduate last year.

An Aberdeen University spokeswoman said: "We welcome these inspections as an opportunity for benchmarking our performance, and providing areas for learning, so that we continually improve in training student dentists for clinical practice.

"Feedback from postgraduate trainers details the very positive contribution and safe practice of previous Aberdeen graduates as they begin their careers as practising dentists."

The university stated that students had been working on patients under the supervision of an experienced senior dental clinician when the "adverse events" had happened.

The spokeswoman added: "The patients involved were made immediately aware of any concern with their treatment and the problems were promptly addressed. There were no complaints from the patients, and all processes within the school were reviewed and further improved."

Jane Pierce, head of education and quality assurance at the General Dental Council, said: "Ensuring patient safety is the core function of the GDC and we are working closely with Aberdeen Dental School to ensure that the issues identified by our inspectors are addressed urgently.

"A further re-inspection will take place in the current academic year."