The General Dental Council (GDC) has now put in place measures to tackle the problems identified.
The Professional Standards Authority for Health and Social Care's (PSA's) Performance Review Report 2013/14 was published on 27 June 2014 and can be read in full here.
Overall the PSA found that the GDC is meeting its statutory requirements.
The GDC is pleased that it has met all the Standards of Good Regulation for standards and guidance and education and training but recognises that it is not acceptable to have failed to meet six standards in Fitness to Practise and two in registration.
Chief executive and registrar of the GDC, Evlynne Gilvarry said: 'We regard failure to meet the PSA's standards as entirely unacceptable and all our efforts are focused on tackling the problems.
'We have increased resources to deal with the continuing surge in caseload and made other key changes to improve the performance of our teams.'
The huge increase in complaints that the GDC continues to experience (110% over the last three years) has put additional strains on the GDC's delivery and resources.
Key measures aimed at tackling the problems include considerable extra investment with new casework teams already in place, alongside a clear focus on management of performance.
GDC chair, Bill Moyes said: 'The number one priority of the new council is to ensure our Fitness to Practise function has the resources it needs to deliver an efficient and effective complaints process.
'We are determined to lead the changes that will result in a much improved performance in a reasonable time.
'We continue to be disappointed that new draft legislation aimed at streamlining healthcare regulation was not included in the Queen's speech.
'However, we are pleased that we have been granted a S60 order to enable a key change to our Fitness to Practise processes, the introduction of case examiners, to bring us in line with other regulators.'