Sir, I write to further the current discussion regarding the use of clinical guidelines in assessing negligence. I was delighted to see that Dr Greene had responded to my previous correspondence (initially in response to Professor Richard's letter outlining a case he had come across) as I believe that often there is a great deal of uncertainty and confusion over how legal claims are assessed for merit. I hope that our letters and the resultant dialogue inform and clarify rather than muddy the waters.

The difference in opinion between Dr Greene and myself is a public example of often what happens behind closed doors in a dental negligence case. Like Dr Greene, I act as an expert in legal cases, but do so in my capacity as a dentist rather than as a specialist. Quite often experts will disagree and they are required to come together and discuss the issues at hand. Whilst I have every respect for Dr Greene, I come at this case from the slightly different viewpoint of a non-specialist GDP. As GDPs we have to balance the pressures of NHS general practice with the desire to provide efficacious and appropriate treatment. This is in line with the spirit of the Bolam test.

In this case of the pertinence of 6 point pocket charting for the assessment of periodontitis, I have no particular issue (although I do not class this to be so myself) with Dr Greene's opinion that failure to carry these out strictly speaking could be classed as a breach of duty. However, as many will be aware, a breach of duty does not automatically lead to a finding of negligence if causation cannot be established. In the case Professor Richards previously described whereby the only deficiency is purported to be a lack of 6 point charting, I still fail to see how, even if this is defined as a breach of duty, this may be responsible for causing a patient's periodontitis to worsen if treated appropriately in every other way.

Dr Greene's approach is of course appropriate, desirable and probably what many would term the 'Gold Standard' with regards to treating periodontitis. However, when faced with the multi-faceted pressures of general practice, one can perhaps be excused for not expecting dentists to always provide 'Gold Standard' treatment that rigidly follows idealised guidelines; after all, patients are not entitled to expect perfect treatment. Providing that any treatment given is found to be acceptable by a reasonable body of professional opinion which has logical basis, no legal claim should succeed.