Improvements to the quality of care at the Royal Dental Hospital in Belfast have not yet been fully implemented, a health watchdog has said.
Significant work has been carried by the Belfast Trust and Health and Social Care Board to address "serious deficiencies" according to the Regulation and Quality Improvement Authority (RQIA) review team.
However, seven out of 22 recommended actions were not considered to have been fully introduced.
The action plan was launched after a report identified problems with the care provided by the hospital and followed concerns over the work of Professor Philip Lamey.
In September, Prof Lamey - the former consultant at Belfast's Royal Victoria Hospital's School of Dentistry - was struck off the dental register and placed under immediate suspension.
In 2011, 135 of Prof Lamey's patients had been recalled after 35 developed cancer.
Four of the patients subsequently died.
A disciplinary panel found Prof Lamey guilty of more than 100 charges of malpractice.
The RQIA will conduct a further assessment of progress against the action plan in 2015-16.