Taking a medical history is an important part of the preoperative assessment of dental patients. The history should be updated at each visit and should contain questions about drug allergy.

The most common allergies in dental practice are to antibiotics. Allergies to local anaesthetics and to some materials used in restorative dentistry have also been reported. When dentists suspect the development of an allergic response, however mild, to any substance they have prescribed or administered or used in restorative procedures, the patient's general practitioner should be informed.

The availability of `paraben-free' local anaesthetics appears to have considerably diminished adverse reactions to local anaesthetic solutions. It appears likely that some of these reactions could have been allergic responses.

Some dental patients have allergies to heavy metals used in dental restorations or prostheses. Allergy to mercury, cobalt or chromium salts occurs. Allergic reactions of this nature are usually local and are usually but not always associated with persistent lesions of the adjacent mucosa. When heavy metal allergies are suspected, the patient should be referred for investigation.

All dentists should be prepared and equipped to give emergency treatment for severe allergic reactions.

R.G. Woods

Australian Dental Association