Dental trauma and avulsed teeth — branching viva

Stage 1 — The knocked-out permanent incisor

Examiner: An eight-year-old boy has fallen on the playground and knocked out his upper left permanent central incisor about five minutes ago. The teacher has brought him holding the tooth wrapped in a tissue. What should have been done at the scene, and what do you do now? [1]

Candidate: The first-aid should have been to find the tooth, pick it up by the crown only and never the root, rinse a dirty root gently under running water for about ten seconds, and replant the permanent tooth immediately into its socket the right way up, then have the child bite gently on a clean handkerchief or gauze to hold it in place. If it could not be replanted it should have gone into cold milk or Hank's balanced salt solution. Now that the tooth is sitting dry in a tissue, the clock is running, so I replant it immediately after a brief rinse, or if I cannot I get it into milk at once and call the dentist. I never scrub the root, never store it in plain water, and never let it dry. [1] [9]

Examiner: Why milk, and why not water? [9]

Candidate: Because the survival of the tooth depends entirely on the periodontal-ligament cells clinging to the root. Milk and Hank's balanced salt solution are physiologically balanced media that keep those cells alive far longer than dry air. Plain water is hypotonic, so it drives water into the cells and ruptures them by osmosis, destroying the very cells that must re-form the attachment. That is why water is contraindicated as a storage medium even though it is fine for a brief rinse. [9]

Stage 2 — Prognosis and definitive management

Examiner: What determines whether this tooth will still be there in ten years? [7]

Candidate: The single most important factor is the extra-alveolar dry time, the time the tooth spent out of its socket and dry. The ligament cells begin to die within minutes on a dry surface and are largely non-viable after about sixty minutes. A tooth replanted within twenty minutes has an excellent prognosis; one dry for over an hour is likely to undergo ankylosis and replacement resorption no matter what we do afterwards. Because this tooth has been dry for only a few minutes, its prognosis is good provided we act now. [1] [7]

Examiner: Once it is replanted, what does the dentist do, and what is your role? [8]

Candidate: The dentist cleans the socket if needed, confirms the position, and applies a short flexible splint for about two weeks, because flexible splinting allows the small physiological movement that protects the healing ligament from ankylosis, unlike rigid wiring. Because this is a closed-apex tooth in an eight-year-old its pulp will necrose, so root canal treatment is started at seven to ten days. A systemic antibiotic course is given, tetracycline in older children and adults or phenoxymethylpenicillin or amoxicillin in younger children, and tetanus prophylaxis is assessed for a contaminated playground wound. My role is to replant or store the tooth correctly, give weight-based analgesia, start the antibiotic pathway, and arrange immediate dental referral with a safety-net for infection or loosening. [1] [8]

Examiner: What are the long-term complications? [1]

Candidate: The two enemies are inflammatory resorption, driven by an infected necrotic pulp and limited by timely root canal treatment, and replacement resorption or ankylosis, which follows death of the periodontal ligament after prolonged dry time and in which the bone fuses to the root and then slowly resorbs it. The tooth can also discolour and may eventually be lost, so follow-up over months and years to monitor pulp vitality and resorption is part of the management. [1] [7]

Stage 3 — The toddler with the primary incisor

Examiner: Now a three-year-old girl has knocked out an upper front primary incisor in a fall, and her mother asks whether it should be put back. What do you tell her? [3]

Candidate: A primary tooth is never replanted. Replanting a primary tooth offers no benefit and risks injuring the developing permanent successor that lies directly beneath it, so the tooth stays out. I control the socket bleeding with gentle pressure, examine the lip for an embedded fragment, give weight-based analgesia, reassure the mother that the permanent tooth will still erupt, and arrange dental review. [3]

Examiner: And how would you approach safeguarding in a child with oral injury? [12]

Candidate: Oral injury in a young child warrants a safeguarding assessment when the history is vague or inconsistent with the injury, when presentation is delayed, when injury is repeated, or when a non-mobile infant has an injury that cannot be explained by a fall, such as a torn upper labial frenulum. I examine the whole child for other injuries and welfare concerns, document carefully, and follow local safeguarding procedures, because oral and dental signs are recognised markers of child abuse. [12]