Sodium Hypochlorite Accident — ORE Part 1 MCQ
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Correct answer: B — Sodium hypochlorite accident (extrusion beyond the apex)
The correct answer is B: sodium hypochlorite accident. Inadvertent periradicular extrusion of sodium hypochlorite during root canal irrigation is characterised by immediate, severe, localised pain coupled with rapid facial swelling, ecchymosis, and hemorrhage—the classic triad described in this case. This iatrogenic complication results from mechanical extrusion beyond the apical constriction, through lateral canals, or via root perforations. Option A (anaphylaxis) is extremely rare and would present with systemic signs; true IgE-mediated hypersensitivity to sodium hypochlorite is not the primary local mechanism here. Option E (surgical emphysema) may occur secondary to aggressive air spray but presents with crepitus and does not explain the acute pain and swelling pattern. Option D (nerve block failure) is unrelated to sodium hypochlorite. Option C (acute periapical abscess) develops over hours to days, not immediately upon irrigation. The temporal relationship to irrigation and the immediate severity of pain and facial swelling make sodium hypochlorite accident the definitive diagnosis.
Reference: Adverse Reaction of Sodium Hypochlorite during Endodontic Treatment of Primary Teeth. PMID: 25883812. International Journal of Clinical Pediatric Dentistry. 2015. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4562052/ AND Bone necrosis as a complication of sodium hypochlorite extrusion. PMID: 39192994. 2022. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9617265/ AND Sodium Hypochlorite Accidents: A Retrospective Case-series Analysis of CBCT Imaging and Clinician Surveys. PLoS One. 2024. https://pubmed.ncbi.nlm.nih.gov/40482705/