New Approach Using Ultrasonic Irrigant Activation and Propolis in Regenerative Endodontics: A Case Report

This study is aimed at describing a clinical case of a regenerative endodontic procedure (REP) in an immature permanent maxillary central incisor with pulp necrosis and apical periodontitis, using a modified protocol that included ultrasonic activation of 1.5% sodium hypochlorite (NaOCl) and 17% EDTA as irrigating solutions, along with an intracanal medicament (ICM) composed of propolis extract and calcium hydroxide (CH) powder, with a 7-year follow-up. An 8-year-old patient underwent an REP on Tooth 11 following trauma to the anterior teeth. Two weeks after procedure, a buccal sinus tract was observed. Cone-beam computed tomography (CBCT) revealed a wide root canal, thin dentinal walls, a periapical osteolytic lesion, and an atypical apical formation resembling an "apical cap", with no evidence of root development on the buccal aspect. With the aim of improving root canal disinfection, ultrasonic activation of the irrigating solutions was performed in cycles, first using 1.5% NaOCl, followed by 17% EDTA, and a final cycle with 1.5% NaOCl. A final rinse with saline was conducted before placement of the ICM, which consisted of propolis extract and CH powder. After 4 weeks, the patient remained asymptomatic, allowing a second REP to be performed. Seven years later, radiographic and tomographic examinations revealed continued root development, increased dentinal wall thickness, and new bone formation. This case report suggests that a second REP incorporating a modified disinfection strategy with ultrasonic activation of irrigating solutions and an ICM based on propolis and CH may be a feasible approach in selected immature permanent teeth with persistent infection following an initial regenerative procedure.