THE Ministry of Health has prepared to extract about 120,000 teeth from the population this year and will use at least 150,000 (a hundred and fifty thousand) carpules of dental anaesthetic in the process. The use of this drug is relatively safe with few complications resulting.

However, the use of local anaesthetics, commonly referred to as “cocaine,” is not without hazard, and we must all be aware of the possibility of untoward reactions.

Patients need to inform their dentists of any history of anaesthetic experiences and whether they have shown any unusual reactions to drugs or allergies. The dentist should know any specific physical condition which may require support or treatment, and any disease for which the patient is or has been under the care of a physician, and the type of treatment, particularly drugs, currently being prescribed.

Most reactions occurring after the injection are potentiated by the anxiety that accompanies the dental appointment, and stress is the major problem to be avoided. Other conditions that may precipitate reactions to local anaesthetics are the following: (1) Low blood sugar levels resulting from fasting before the dental appointment.

This is probably the foremost factor in fainting, so the patient must have had his/her regular meal. People who skip breakfast are prime candidates for fainting (2) Extremes in temperature. Heat exhaustion will exacerbate reactions (3) Any debilitating disease. Disease is a prime agent in reducing the ability to respond to stress (4) Pregnancy. This patient is sensitised much like the allergic type. She has an increased blood level of steroids and needs careful handling.

Studies show that two to three out of every 100 members of the public will fall into the category of problem-management cases. Most of these individuals have special requirements and I will examine some of them.

Patients with cardiovascular (heart and blood vessels) diseases will probably be on special medications such as Reserpinr or Serpasil, digitalis derivatives (Digoxin), diuretics (Lasix), and tranquilisers (Valium). All these drugs may interact with the anaesthetic used when an extraction is done.

Respiratory diseases, which include emphysema and asthma, cause limitations of the oxygenation mechanism. Since fear results in
increased respiration, the dental-chair apprehension may cause a deficit.

Patients with allergic diseases often manifest with a history of hay fever, asthma, angioedema, contact dermatitis (“ mad blood”), etc. There will often be a familial history of sensitivity. Atopic types in extreme cases show a reaction to the offending antigen ( the anaesthetic) and may develop severe anaphylaxis and die from the injection of small amounts of the injection.

Many persons take anti-coagulant therapy for stroke prevention and do not know. When it takes more than 10 minutes for a wound to stop bleeding, or if a woman menstruates over six days, there is the probability of that person having a blood clotting problem.

Finally, individuals receiving steroid therapy do not respond well to stress. Those being treated for hyperthyroidism may have to be sedated. Uncontrolled diabetics should never have dental treatment or healing and post-operative infection will be a problem.