MJDF Human Disease

Question 1

A patient with rheumatic heart disease and a prosthetic mitral valve presents for dental treatment. What is the primary cardiac concern during dental procedures?

Accepted Answer

Risk of infective endocarditis from transient bacteraemia caused by invasive dental procedures, though NICE guidelines no longer recommend routine antibiotic prophylaxis in the UK

Answer

Patients with prosthetic heart valves are at the highest risk of infective endocarditis (IE), which can be caused by bacteraemia from invasive dental procedures (extractions, scaling, root canal treatment). Oral streptococci (especially Streptococcus mutans and S. sanguinis) can colonise damaged or prosthetic valves. However, NICE CG64 in the UK recommends AGAINST routine antibiotic prophylaxis for dental procedures, differing from AHA/ESC guidelines. Emphasis is placed on maintaining good oral health to reduce chronic bacteraemia. The dentist should document the discussion of risks with the patient and their cardiologist.

Question 2

What is the significance of a patient's ASA (American Society of Anesthesiologists) classification in dental practice?

Accepted Answer

It classifies patients by their physical health status to assess fitness for treatment under sedation or general anaesthesia, ranging from ASA I (healthy) to ASA V (moribund); it guides the level of monitoring, setting, and modifications needed for safe dental care

Answer

The ASA classification is widely used in dentistry to assess patient fitness: ASA I — normal healthy patient; ASA II — mild systemic disease (well-controlled hypertension, mild asthma, pregnancy); ASA III — severe systemic disease limiting activity (poorly controlled diabetes, stable angina, COPD); ASA IV — severe systemic disease that is a constant threat to life (recent MI, severe heart failure); ASA V — moribund patient. Most general dental practice treats ASA I-II patients. ASA III patients may require modifications (shorter appointments, stress reduction, medical liaison). ASA IV patients typically require hospital-based dental care.

Question 3

A patient presents with a history of adrenal insufficiency (Addison's disease) and takes daily prednisolone 10mg. What is the risk during a stressful dental procedure and how should it be managed?

Accepted Answer

The patient may develop an adrenal crisis (acute adrenal insufficiency) if the hypothalamic-pituitary-adrenal axis cannot mount an adequate cortisol response to stress; management depends on the procedure complexity — for minor procedures under LA, the usual dose is adequate; for more stressful procedures, supplementary corticosteroid cover may be needed

Answer

Patients with adrenal insufficiency on replacement corticosteroids may be unable to produce additional cortisol in response to physiological stress (surgical procedures, infections, trauma), risking adrenal crisis (hypotension, tachycardia, collapse). Current guidelines suggest: for minor procedures under LA with good anxiety management, the usual daily dose is typically sufficient; for surgical procedures or where significant stress is anticipated, doubling the usual dose on the day of the procedure is recommended. IV hydrocortisone 100mg should be available for emergencies. Never abruptly stop corticosteroid therapy.

Question 4

What are the dental implications of a patient undergoing head and neck radiotherapy?

Accepted Answer

Complications include mucositis, xerostomia (permanent if salivary glands are in the radiation field), radiation caries, osteoradionecrosis of the jaws, trismus from fibrosis of muscles of mastication, altered taste, and candidiasis; pre-radiotherapy dental assessment and extractions of poor-prognosis teeth are essential

Answer

Head and neck radiotherapy (typically 50-70 Gy) causes multiple oral complications: acute mucositis (within 1-2 weeks), xerostomia (may be permanent if major salivary glands receive >30 Gy), radiation caries (rampant cervical caries due to xerostomia and altered flora), osteoradionecrosis (ORN — avascular necrosis of irradiated bone, risk highest in mandible), trismus (from fibrosis of masticatory muscles), dysgeusia, and candidiasis. Pre-radiotherapy dental management includes extracting teeth with poor prognosis at least 2-3 weeks before radiotherapy, fluoride tray fabrication, and oral hygiene optimization. Post-radiotherapy extractions must be avoided if possible or performed with hyperbaric oxygen/pentoxifylline-tocopherol protocols to reduce ORN risk.

Question 5

A patient with liver cirrhosis presents for dental treatment. What are the key medical considerations?

Accepted Answer

Impaired coagulation (reduced clotting factor synthesis), altered drug metabolism (prolonged action of hepatically-metabolised drugs), increased infection risk, and potential for excessive bleeding requiring pre-treatment coagulation screen (INR, platelet count) and possible liaison with hepatologist

Answer

Liver cirrhosis has multiple dental implications: impaired synthesis of clotting factors (II, V, VII, IX, X) causing coagulopathy (check INR, platelet count, bleeding time); altered metabolism of drugs cleared by the liver (avoid or reduce doses of paracetamol, diazepam, lidocaine); thrombocytopenia from portal hypertension/splenism; increased infection susceptibility; potential hepatitis B/C co-infection requiring infection control measures; and alcohol-related cirrhosis may indicate oral cancer risk. Pre-treatment assessment should include recent blood tests, medical liaison, and consideration of local haemostatic measures for surgical procedures.

MJDF Part 1 Practice Test

MJDF Part 1 Practice Test

MJDF Human Disease