Infection Control · patient case question
Which bloodborne pathogen poses the GREATEST occupational infection risk in the dental office?
Patient case: HIV, and a Platelet Count of 18,000
Patient: 42-year-old male
Chief Complaint: Sore mouth and a broken tooth requiring extraction.
Background: HIV positive for eleven years. Recently changed antiretroviral regimen. Brings recent laboratory results.
Medications: Antiretroviral therapy
Vital Signs: BP 122/76 mmHg · HR 78 bpm · RR 16 · T 98.6°F
Findings: Laboratory: CD4 410 cells/µL, viral load undetectable, haemoglobin 13.1 g/dL, PLATELETS 18,000/µL, INR 1.0. Intraorally, removable white plaques on the buccal mucosa and palate that leave an erythematous base when scraped.
Show answer and explanation
Correct answer: B. Hepatitis B
- A. HIV carries a transmission risk of roughly 0.3% after percutaneous exposure — real, but roughly a hundredfold lower than hepatitis B.
- B. CORRECT. HEPATITIS B is by far the greatest occupational bloodborne risk. Transmission after a percutaneous exposure from an HBeAg-positive source is roughly 22–31% — orders of magnitude higher than the others. HBV also survives on environmental surfaces in dried blood for at least seven days, so indirect transmission is possible. This is precisely why the hepatitis B vaccine is mandated and why OSHA requires employers to offer it free of charge.
- C. Hepatitis C carries a risk of roughly 1.8%. Higher than HIV, far lower than HBV, and there is no vaccine — but the occupational risk in dentistry remains well below HBV.
- D. Tuberculosis is a genuine occupational concern in dentistry but it is AIRBORNE, not bloodborne, and is not the answer to a bloodborne-pathogen question.
Note: Post-exposure priorities: wash immediately, report, source testing, and evaluate for prophylaxis. HIV PEP should begin as soon as possible, ideally within hours and no later than 72 hours.
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