Pediatric Dentistry · patient case question
What is the most likely cause?
Patient case: Child with lower lip swelling the day after a stainless steel crown
Patient: Child, 7 years old
Chief complaint: Brought by his father with swelling of the lower lip.
Background: A stainless steel crown was placed the day before under local anaesthesia.
Current findings: Swelling of the lower lip at the level of the mandibular occlusal plane.
Show answer and explanation
Correct answer: D. Trauma — self-inflicted lip biting while the lip was anaesthetised
- A. Infection appearing within 24 hours of crown placement, localised to the lip rather than the vestibule or face, does not fit.
- B. Nickel allergy from a stainless steel crown is rare and would not present as isolated lip swelling at the occlusal line.
- C. Anaesthetic allergy manifests immediately as urticaria, angio-oedema or anaphylaxis, not as delayed lip swelling the following day.
- D. CORRECT. This is the classic paediatric post-anaesthetic complication. Following an inferior alveolar nerve block the lip is numb, and children chew, bite or suck the insensate tissue, producing a traumatic ulcer and swelling that appears hours later, once sensation returns. The timing and location at the occlusal plane are diagnostic.
Note: Prevention is the exam point: warn the child AND the caregiver before they leave, and consider a cotton roll or a warning sticker.
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