Pediatric Dentistry · patient case with 4 questions
Avulsed Central Incisor on the Soccer Field
Patient: 8-year-old male
Chief Complaint: “His tooth got knocked out at soccer practice.”
Background: Healthy, immunizations current, no allergies. Tooth #8 was avulsed 35 minutes ago. The coach placed it directly into a container of Hank’s Balanced Salt Solution from the sideline kit. No loss of consciousness, no other injuries.
Medications: None
Vital Signs: BP 100/64 mmHg · HR 98 bpm · RR 20 · T 98.6°F
Findings: Empty socket at #8 with no alveolar fracture. The avulsed tooth is intact with a wide open apex and short root (approximately two-thirds formed). Adjacent teeth #7 and #9 are firm and respond within normal limits.
Question 1
If Hank’s Balanced Salt Solution had not been available, which of the following would have been the best alternative storage medium?
Show answer and explanation
Correct answer: D. Cold milk
- A. Incorrect. Tap water is hypotonic. Osmotic influx causes PDL cells to swell and lyse rapidly, and it is the single worst common storage medium — markedly worse than dry storage for short intervals.
- B. Incorrect. Dry storage kills PDL cells quickly. After 60 minutes dry, the ligament is considered non-viable and the tooth is managed as a delayed replantation with an expected ankylotic outcome.
- C. Incorrect. Chlorhexidine is cytotoxic to periodontal ligament cells. It has no role as a storage medium.
- D. Correct. Milk is the best widely available medium. It is roughly isotonic, has a physiologic pH, contains growth factors, and is relatively free of bacteria, so it preserves periodontal ligament cell viability for several hours. Saliva and saline are acceptable but inferior.
Question 2
After the tooth is replanted, how long should it be stabilized, and with what type of splint?
Show answer and explanation
Correct answer: B. Two weeks with a passive, flexible splint
- A. Incorrect. Four weeks with a more rigid splint is indicated only when there is an associated alveolar or jawbone fracture, which this patient does not have.
- B. Correct. The 2020 IADT guidelines direct that the replanted tooth be stabilized for 2 weeks with a passive, flexible wire up to 0.016 inch or 0.4 mm in diameter. Flexibility permits physiologic movement, which encourages periodontal ligament healing rather than ankylosis.
- C. Incorrect. Rigid splinting restricts physiologic mobility and increases the risk of replacement resorption and ankylosis. It is reserved for bony injuries.
- D. Incorrect. Eight weeks far exceeds any recommended interval and would substantially increase the risk of ankylosis and plaque-related complications.
Note: Correction to source. The recall recorded “one week.” The 2020 IADT guideline is 2 weeks flexible for avulsion, extended to 4 weeks only with an associated alveolar fracture. The older 7–10 day figure comes from the previous guideline generation and still circulates in study material.
Question 3
Given the wide open apex, how should the pulp be managed after replantation?
Show answer and explanation
Correct answer: A. Withhold root canal treatment and monitor closely for revascularization
- A. Correct. In an immature tooth, spontaneous revascularization of the pulp space is possible and is the goal, since it permits continued root development and thicker dentinal walls. Endodontic treatment is withheld and started only if pulp necrosis or infection-related resorption is later confirmed clinically or radiographically.
- B. Incorrect. Apexification presupposes a necrotic pulp. It is not performed prophylactically at the time of replantation.
- C. Incorrect. That protocol applies to a closed apex, where revascularization will not occur and treatment is begun before splint removal to prevent inflammatory resorption. Applying it here forfeits the chance of continued root maturation.
- D. Incorrect. Extraoral pulp extirpation prolongs extra-alveolar time and further damages the periodontal ligament. Replantation speed is the priority.
Note: Flagged — the source recorded “after 2 weeks.” That figure applies to a closed apex, where endodontic treatment is initiated before the splint comes off. This patient has an open apex, which reverses the recommendation. Watch closely: inflammatory root resorption progresses very rapidly in children, so short-interval recall is essential.
Question 4
Two years later the replanted tooth has developed a persistent gray-brown discoloration. What is the underlying cause?
Show answer and explanation
Correct answer: B. Breakdown products of red blood cells within the dentinal tubules
- A. Incorrect. Endotoxins are inflammatory mediators, not pigments. They contribute to periapical pathosis but do not themselves color dentin.
- B. Correct. Trauma ruptures pulpal vessels and blood enters the dentinal tubules. Hemoglobin is degraded to hemosiderin and related iron-containing pigments, which stain dentin gray-brown and are visible through the translucent enamel.
- C. Incorrect. Leukocyte breakdown does not generate a chromogenic pigment in meaningful quantity, and it is not a recognized cause of intrinsic tooth discoloration.
- D. Incorrect. Excess fluoride during tooth development causes fluorosis — diffuse white opacities or, when severe, brown mottling with pitting. It would have been present since eruption and would affect multiple teeth.
Note: Post-traumatic discoloration does not by itself confirm necrosis. Some discolored teeth remain vital, and a proportion of gray teeth lighten over time. Base the endodontic decision on the full picture: sensibility testing, percussion, and radiographic follow-up.