Delayed expression of dental trauma-induced external root re
A 10-year-old girl presented for treatment of an upper right central incisor (#11) avulsion. Her tooth was traumatized approximately 30 min prior during a sports activity at school. The oral examination showed a #11 avulsion and a minor gingival laceration wound. The upper right lateral incisor left central incisor and left lateral incisor were examined, but no severe mobility was found. The #11 radiograph showed incomplete root apex formation and no obvious root fracture. Following the IADT guidelines, the patient was placed under local anesthesia; #11 and its socket were cleaned with normal saline, and #11 was placed gently back into its alveolar socket.

Splinting was done with 0.022×0.025 inches of twist wire from the maxillary right canine to the left canine, which was left for two weeks, and the patient was prescribed antibiotics. Root canal treatment #11 was initiated 7 days after replantation with calcium hydroxide used as an intra-canal medicament for apexification. The #11 follow-up radiographs showed nothing specific after four months. Six months later, the patient began orthodontic treatment for the purpose of alignment. Unfortunately, 29 months after the initial trauma, #11 developed a gingival fistula, and the radiograph showed external resorption at the middle root. Orthodontic treatment was immediately stopped. Systemic antibiotics were given for two weeks until the fistula disappeared. Tooth #11 was stabilized and maintained in the mouth up to the present time.

Calcium hydroxide has been shown to arrest and repair external inflammatory root resorptive defects, eliminate the endodontopathic microorganisms from the root canal, and induce hard-tissue barrier formation at the apex of non-vital immature teeth. The traditional application of calcium hydroxide to induce apexification is gradually being replaced by mineral trioxide aggregate (MTA) as a one-step technique.4 The present avulsion tooth case showed that root resorption can occur after a long period of time. Thus, additional dental work should be undertaken with caution in clinical settings.