Oral Surgery · patient case with 5 questions
Face-First Fall on Concrete
Patient: 34-year-old male
Chief Complaint: “I tripped and landed on my face on the sidewalk.”
Background: Healthy. No loss of consciousness, no nausea, no visual disturbance. Tetanus status current. Injury occurred approximately 5 hours ago.
Medications: None
Vital Signs: BP 128/78 mmHg · HR 84 bpm · RR 16 · T 98.4°F
Findings: Chin shows a broad, raw, superficially scraped area with punctate bleeding and embedded grit. The inner surface of the lower lip has a full-thickness tear with irregular edges. Teeth #7 and #8 are fractured with frank pulp exposure, tender to percussion, mature apices. Tooth #6 is intact, non-mobile, responds normally to cold, with no radiographic changes.
Question 1
The broad, raw, scraped area on the chin is best classified as which type of soft tissue injury?
Show answer and explanation
Correct answer: A. Abrasion
- A. Correct. An abrasion is a superficial wound produced by frictional rubbing away of the epithelium, leaving a raw bleeding surface. Foreign debris embedded in the wound is characteristic and must be scrubbed out to prevent traumatic tattooing.
- B. Incorrect. A contusion is a bruise — subcutaneous bleeding with the surface epithelium intact. There is no open surface, and no debris can enter.
- C. Incorrect. A laceration is a tear through tissue produced by a sharp or shearing force. It is a discrete cut with depth, not a broad superficial scrape.
- D. Incorrect. An avulsion is the complete tearing away of a segment of tissue, leaving a defect. Nothing has been removed from the chin.
Question 2
The full-thickness tear with irregular edges on the inner surface of the lower lip is best classified as which type of injury?
Show answer and explanation
Correct answer: D. Laceration
- A. Incorrect. Ecchymosis is a flat area of submucosal or subcutaneous hemorrhage with an intact surface — a bruise, not a tear.
- B. Incorrect. An abrasion is superficial epithelial loss without a full-thickness breach, which is what is present on the chin rather than the lip.
- C. Incorrect. An aphthous ulcer is a recurrent immune-mediated ulceration with a yellow-gray pseudomembrane and an erythematous halo. It is unrelated to trauma and would not appear acutely after a fall.
- D. Correct. A laceration is a tear extending through the full thickness of the tissue, produced when soft tissue is crushed against the teeth. Ragged edges are typical, and the wound must be explored for tooth fragments before closure.
Note: Always radiograph the lip when a tooth fragment is unaccounted for. A soft tissue view with reduced exposure will reveal embedded enamel or dentin fragments that would otherwise cause chronic infection.
Question 3
Teeth #7 and #8 have frank pulp exposures with mature apices, and 5 hours have elapsed. What is the appropriate definitive management?
Show answer and explanation
Correct answer: C. Root canal treatment
- A. Incorrect. Direct pulp capping is reasonable for a small, fresh exposure treated within hours in a tooth with an immature apex, where preserving vitality supports continued root development. In a mature tooth exposed for 5 hours, its prognosis is poor. A partial pulpotomy would be the more defensible vital option in that window.
- B. Incorrect. Both teeth are restorable. Crown fracture with pulp exposure is not an indication for extraction when adequate tooth structure remains.
- C. Correct. With a mature apex, a frank exposure, and a delay of several hours, the pulp is contaminated well beyond the superficial layer. Root canal treatment provides the predictable outcome and permits definitive restoration of the fractured crowns.
- D. Incorrect. An exposed pulp left untreated will become necrotic and infected. Observation is not an option once the pulp is exposed to the oral environment.
Question 4
Tooth #6 is intact, non-mobile, responds normally to cold, and shows no radiographic change. What is the appropriate management?
Show answer and explanation
Correct answer: D. Monitoring with periodic clinical and radiographic reevaluation
- A. Incorrect. There is no indication to treat a vital, asymptomatic tooth. Prophylactic endodontics is never appropriate on this basis.
- B. Incorrect. Nothing about this tooth suggests it cannot be retained.
- C. Incorrect. There is no structural loss to restore. A crown would remove sound tooth structure for no benefit.
- D. Correct. A tooth adjacent to a traumatic injury may develop delayed pulpal necrosis months later even when it initially tests within normal limits. Serial follow-up at roughly 6–8 weeks, 6 months, and 1 year is the standard.
Question 5
Three weeks later a persistent nodule at the lip laceration site requires an incisional biopsy. Which structures are at greatest risk during this procedure?
Show answer and explanation
Correct answer: C. Inferior labial artery and branches of the mental nerve
- A. Incorrect. The superior labial artery and infraorbital nerve supply the upper lip. They are not encountered during a lower lip procedure.
- B. Incorrect. The lingual artery and lingual nerve are floor-of-mouth and tongue structures with no relationship to the labial mucosa.
- C. Correct. The inferior labial artery, a branch of the facial artery, runs between the orbicularis oris and the labial mucosa of the lower lip and is readily palpable. Terminal branches of the mental nerve supply sensation to the lower lip and vermilion; injury produces persistent numbness.
- D. Incorrect. The facial artery courses at the anteroinferior border of the mandible before ascending, well away from the lip. The long buccal nerve supplies the buccal mucosa and gingiva of the mandibular molars.
Note: Practical technique for lower lip biopsy: orient the incision parallel to the vermilion border, remain superficial to the orbicularis oris, and stabilize the lip with digital pressure or a chalazion clamp to control the labial vessels.