Zsolt Lohinai

The consequences of traumatic injuries are pulp necrosis, periapical inflammation, and possible external cervical resorption (ECR). The concomitant cessation of root maturation and dentinogenesis in premature teeth result in a fragile tooth. Revascularization of the pulp might be an alternative treatment option. A 12-year-old patient was referred for retreatment of chronic apical periodontitis with acute exacerbation after root canal treatment of an upper central incisor. During gutta-percha removal, an ECR was detected. First, it was closed internally with Biodentine, followed by an external composite closure after a cone beam computed tomography evaluation. In the first session, chemomechanical cleaning was aided with sodium hypochlorite and hyperpure chlorine dioxide, and the canal was dressed with Ca(OH)2 until the next session. In the next session, only the low-toxicity, but adequate, bactericide hyperpure chlorine dioxide was applied for irrigation, before the provocation of periapical bleeding into the canal. The blood clots were covered with Biodentine, and the tooth was restored with composite filling. During the 24-month follow-up, clinical signs/symptoms had disappeared, and the periapical lesion was resolved. Increased root thickness in the apical third and decreased size of the apical foramen were detected. In conclusion, regenerative endodontic procedures could potentially be used to retreat immature teeth with persistent apical periodontitis and external cervical resorption.