Pharmacology, Anesthesia and Emergency Medicine
This domain tests safe drug use in dentistry: local anaesthetic selection and dose calculation, antimicrobial and analgesic prescribing, drug interactions, and the recognition and immediate management of medical emergencies in the chair.
Local anaesthetics
All are weak bases that block sodium channels in the nerve membrane. Onset and potency depend on pKa and lipid solubility; vasoconstrictor prolongs duration and reduces systemic absorption.
- Lidocaine 2% with 1:100,000 adrenaline: maximum about 4.4 mg/kg (commonly capped at 300 mg). A 2% solution is 20 mg/mL.
- Articaine 4%: maximum about 7 mg/kg; higher reported rates of persistent paraesthesia after inferior alveolar block.
- Mepivacaine 3% plain: about 6.6 mg/kg; useful when adrenaline is best avoided, at the cost of shorter duration.
- Prilocaine: metabolised to ortho-toluidine, so high doses risk methaemoglobinaemia.
- Bupivacaine 0.5%: long-acting, useful for postoperative pain control.
Prescribing
Amoxicillin remains first-line for odontogenic infection; metronidazole or amoxicillin-clavulanate cover failures or anaerobe-dominant infections; erythromycin and azoles inhibit CYP3A4 and can raise INR in warfarin patients. Antibiotic prophylaxis for infective endocarditis is reserved for the highest-risk groups (prosthetic valves, previous endocarditis, specified congenital heart disease) at a single 2 g amoxicillin dose 30–60 minutes preoperatively. NSAIDs are first-line analgesics; codeine is contraindicated in children under 12.
Emergencies
The commonest emergency is vasovagal syncope - supine position, legs raised, oxygen, monitor. Anaphylaxis needs intramuscular adrenaline 0.5 mg (0.5 mL of 1:1000) into the anterolateral thigh, repeated as needed, plus oxygen and fluids. Angina is treated with rest and glyceryl trinitrate; suspected myocardial infarction with 300 mg aspirin and emergency transfer. Hypoglycaemia requires oral glucose if conscious, glucagon or intravenous glucose if not; an adrenal crisis needs hydrocortisone.
Worked example
A 20 kg child needs a mandibular block. Lidocaine 2% with 1:100,000 at 4.4 mg/kg gives a maximum of 88 mg. A 2% solution contains 20 mg/mL, so the ceiling is 4.4 mL (88 mg divided by 20 mg/mL). Reasoning explicitly in mg first, then converting to millilitres, prevents the classic tenfold error.
Traps that cost marks
- Calculating dose in millilitres without converting to milligrams.
- Giving adrenaline to a patient with stable angina before trying rest and nitrates.
- Prescribing antibiotics instead of drainage for a fluctuant abscess.
- Overlooking methaemoglobinaemia risk with prilocaine in children.
Professional Ethics, Legislation and Practice Management
This domain tests the non-clinical framework of practice: consent, confidentiality, record keeping, scope of practice, team delegation, infection control and the governance systems that keep a practice safe and lawful.
Consent
Valid consent requires capacity, adequate and understood information, and voluntariness. It is a process, not a signature, and it must cover material risks, alternatives including doing nothing, and likely costs. Capacity is presumed in adults; assess it functionally (understand, retain, weigh, communicate). Children may be competent to consent to their own treatment depending on maturity and jurisdiction - the Gillick principle in the United Kingdom is the familiar model - but local law governs. Document what was discussed, not merely that a form was signed.
Confidentiality and records
Patient information is confidential and, in Europe, protected by data protection law such as the GDPR. Share only on a need-to-know basis, obtain consent before disclosing to third parties, and secure records against unauthorised access. Clinical records must be contemporaneous, legible, factual, attributable and retained for the period required locally. Corrections should be dated additions, never deletions.
Scope, delegation and governance
Work only within your competence and refer when the case exceeds it. Delegation to hygienists, therapists, nurses and technicians requires appropriate training, supervision and legal authority in your jurisdiction. Verify indemnity cover, registration and continuing professional development for every clinician.
Infection control
Follow a validated decontamination pathway: cleaning, disinfection, inspection, packaging, autoclave cycles with validation, and traceability. Segregate sharps immediately, use single-use items where indicated, and audit compliance.
Worked example
A competent adult declines a radiograph needed to plan a root canal, saying she has read that radiation is dangerous. Reasoning: she has capacity and the right to refuse. Explain the diagnostic purpose and the risks of proceeding without it, offer alternatives such as a smaller field of view, record the discussion and the informed refusal, and if treatment cannot be provided safely, explain this and offer referral rather than proceeding blindly or dismissing her.
Traps that cost marks
- Treating a signed form as proof of valid consent.
- Discussing a patient's care in a corridor or posting identifiable images online without consent.
- Delegating tasks outside the team member's training, or to unregistered staff.
- Recording opinions rather than findings, or backdating entries.