An Innovative Approach for Retrieval of a Separated Intracanal File Using Guided Endodontics: A Case Report

A separated instrument in a root canal limits accessibility for chemo-mechanical preparation, making its retrieval imperative for a good prognosis. Among the numerous techniques available for instrument retrieval, guided endodontics is arguably the most predictable. This case report describes a stepwise approach for instrument retrieval using a surgical drill guided by a 3D-constructed acrylic template with the aid of cone beam computed tomography (CBCT). A 22-year-old male patient of North Indian origin presented with a chief complaint of discoloration and pain in tooth 21. Radiographic examination revealed poor obturation and fractured instruments in the middle third of the root canal. A diagnosis of a previously treated tooth with symptomatic apical periodontitis was made. After obtaining the patient's consent, CBCT imaging and an intraoral scan were performed to generate Digital Imaging and Communications in Medicine (DICOM) and standard tessellation language (STL) files, respectively. These files were merged using Blue Sky Plan software (Blue Sky Bio, LLC; Grayslake, Illinois) to create a virtual drill path, which was subsequently used to fabricate a 3D acrylic guide, leading to the successful retrieval of the fractured instrument. Guided endodontics offers a predictable method for fractured instrument retrieval.