The Government insists that its new NHS contract will deal with the problems because dentists' pay will for the first time depend on high quality care and patient satisfaction / getty images
Undercover researchers reveal alarming lack of care in NHS and private practices

An undercover investigation has exposed poor quality assessments, inadequate examinations and treatment plans among NHS and private dentists.

Essential tests and X-rays to diagnose decay, gum disease and infections were not adequately carried out by more than half of the NHS dentists in the snapshot investigation by Which?

Three quarters of all the dentists visited – 10 private and 10 NHS – failed to check soft tissue inside the mouth which can help detect oral cancer which is the sixth most common malignancy in the UK.

Undercover researchers found assessments were kept short – 11minutes on average – which experts say makes it "near impossible" to properly assess a new patient. Eight of the NHS and five of the 10 private dentists gave inappropriate advice and some missed the need for essential treatment. Just three of the visits were rated "good".

The findings are the latest indication of problems which have "tempted dentists to cut corners" with prevention, risk assessment, quality and proper treatment planning, according to Stephen Dunne, professor of primary dental care at King's College London.

NHS dentists are paid one of three rates for every patient, a system that has led to a rapid increase in tooth extractions as an alternative to more time consuming, and therefore expensive, root canal work, according to official NHS statistics. They are currently not paid to carry out oral health checks or give patients advice on how to avoid gum disease or decay, though these are an essential part of good practice guidelines for all dentists.

The Government insists that its new NHS contract, currently being piloted, will deal with the problems because dentists' pay will for the first time depend on high quality care and patient satisfaction. But some experts warn the plans will be undermined unless more resources are found.

Professor Dunne said: "I am reassured by the principles... that underlie the new contract which are already applied by UK dental schools and good practitioners. But, I am not confident that the finances for the new contract will be adequate given the current economic climate."

But Wagner Marcenes, professor of oral epidemiology at Queen Mary, University of London, said: "The new contract will contribute favourably as dentists will be rewarded for prevention, patient satisfaction, quality of treatments and improvements if oral health."

A Department of Health spokesman said: "Poor care of any kind is unacceptable. While this survey only covers a very small number of practices, the findings will be considered by the General Dental Council, who set and monitor professional standards for both NHS and private dentists."