Successful Regenerative Endodontic Therapy of a Dens Evaginatus Mandibular Second Premolar with an Acute Apical Abscess and Extensive Periapical Bone Loss: A Case Report

Regenerative endodontics is a rapidly growing field within dentistry that aims to replace damaged tooth structures and cells of the pulp-dentin complex. This case report presents the successful management of an immature permanent second mandibular premolar with an acute apical abscess and extensive apical bone loss caused by a dens evaginatus. This tooth was unexpectedly treated with long-term calcium hydroxide (Ca(OH)₂) that was replenished several times over 6 months. During the treatment process, this tooth became reinflamed developing a chronic apical abscess after resolution of the initial acute apical abscess, which resulted in the replacement and prolonged use of Ca(OH)₂. The final regenerative procedures were completed using a bioceramic fast set putty placed directly over the blood clot and an occlusal composite restoration. At the 6-month follow-up, the patient was asymptomatic with a fully healed radiographic lesion, new periodontal ligament, and the apex closed with thickening of the mesial and distal aspects of the root. At the 15-month follow-up, the patient remained asymptomatic with continued evidence of radiographic development of the apical aspect of this tooth, displaying root end closure and thickening. This is a unique case report of the management of a complex infection process in an immature tooth with regenerative techniques with repeated and long-term use of Ca(OH)₂. This novel report provides dental practitioners with a new potential protocol for the management of these immature cases with advanced periapical infections that require extensive disinfection to have successful outcomes.