Sir, I should also like to thank the authors of the NICE clinical guideline 64 'Prophylaxis against infective endocarditis' for their clarity on such an important issue (Keightley A. Turned on its head. Br Dent J 2008; 204: 544).

Gone is the conundrum of whether or not to give antibiotic cover for that new patient with a history of rheumatic fever who has clearly had extractions in the past without antibiotic cover with no adverse effect.

I remember as a student the obsession everyone had with the prevention of endocarditis in the 'at risk' patient. So much so that it impinges heavily on my memory of the day of my final examinations at Liverpool in 1972.

Some students were allocated a patient who had turned up in the admissions department that day for emergency treatment and we were required to diagnose their problem and if necessary treat them.

My patient had attended with toothache and wanted a tooth extracting. After taking a medical history I discovered that she had had rheumatic fever but she had no knowledge of any heart valve damage. On examination of her mouth it was clear that she had had extractions in the past without antibiotic cover.

When I presented the patient to the examiners the majority of the 'grilling' revolved around the prevention of endocarditis rather than the treatment which the patient needed. The patient at this point was becoming quite agitated listening to the sequelae that could befall her.

Because of the time restraints of the examination I never did get to extract the tooth. The patient had to go to another department for an injection of 'Triplopen' (treatment of choice in 1972 at Liverpool) and wait an hour before the tooth was extracted.

Now I will be able to carry out emergency treatment immediately for the 'at risk' patient, after of course, the necessary counselling!