Medical emergencies in the dental chair

What it is

Dental treatment combines anxiety, pain, injected drugs, an upright or supine position and sometimes sedation, so medical emergencies happen in dental settings. Vasovagal syncope is the most frequent: pallor, sweating, nausea, slow pulse and brief loss of consciousness, recovering quickly when lying flat with the legs raised. Other emergencies are hypoglycaemia in people with diabetes who skipped a meal, asthma attacks, angina and myocardial infarction, seizures, anaphylaxis (to latex, antibiotics or, very rarely, local anaesthetics), local anaesthetic systemic toxicity, oversedation and aspiration of a dental instrument or tooth. Every practice needs trained staff, oxygen and a basic emergency drug kit.

How to recognise it

• Syncope: lie flat, raise legs, loosen clothes, oxygen; recovery within a minute or two.
• Anaphylaxis: urticaria, angioedema, wheeze, hypotension; intramuscular adrenaline is first line.
• Hypoglycaemia: oral glucose if awake; glucagon or intravenous glucose if not.
• Chest pain: stop treatment, sit up, glyceryl trinitrate, aspirin if no contraindication, call emergency services.
• Oversedation with benzodiazepines or opioids: airway support, then flumazenil or naloxone.

What to do at once

1. Stop the procedure, remove instruments from the mouth and call for help.
2. Assess airway, breathing and circulation; check responsiveness, pulse, oxygen saturation and glucose.
3. Position: flat with legs raised for syncope; sitting up for breathing difficulty or chest pain.
4. Give oxygen and the specific first-line treatment for the emergency recognised.
5. Start basic life support if there is no normal breathing, and use a defibrillator if available.
6. Call emergency services for anything other than a fully recovered faint.

Costly mistakes

• Hypoglycaemia can look like a faint or anxiety; always check glucose in a person with diabetes.
• Treating anaphylaxis with antihistamines alone and delaying adrenaline is a classic fatal error.
• A patient who does not recover from a «faint» within a few minutes has another diagnosis.

Next step / Initial management

• Every emergency: document the event and drugs given, and refer the patient to medical care unless it was a simple faint with full recovery.
• After anaphylaxis: observe in hospital, refer to allergy services to identify the trigger, and record the allergy.
• Prevent: take a medical history and drug list before treatment, schedule anxious patients early, ensure people with diabetes have eaten.

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Educational content; it does not replace assessment by a dentist or doctor and is not a clinical instruction. For facial or neck swelling with difficulty swallowing or breathing, a knocked-out tooth or bleeding that will not stop, go to an emergency department at once.

Sources: Anaphylaxis (StatPearls Publishing (NCBI Bookshelf), 2023); Local Anesthetic Toxicity (StatPearls Publishing (NCBI Bookshelf), 2026); Conscious Sedation in Dentistry (StatPearls Publishing (NCBI Bookshelf), 2023).

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