Robot-Assisted Endodontic Retreatment: A Case Report with Clinical Considerations

Fiber posts present significant challenges for nonsurgical endodontic retreatment, as improper removal may result in iatrogenic root perforation or even root fracture. Recently, robotic technology has attracted considerable attention in dentistry and active dental robotic (ADR) systems can perform procedures based on preset instructions, minimizing reliance on the dentist's experience. This case report describes the application of an ADR system for fiber post removal through an existing zirconia crown. A 26-year-old female was diagnosed with previously treated, symptomatic apical periodontitis of the mandibular left second premolar. Based on cone-beam computed tomography (CBCT) and intraoral scanning, the ADR system was used to achieve precise fiber post removal through a zirconia crown with minimally invasive coronal access under rubber dam isolation. The robotic arm executed flexible pumping motions to simulate the hand movements of dentists. This was achieved by establishing preset force and distance thresholds tailored to the characteristics of the materials being drilled. Residual gutta-percha was removed, followed by canal preparation and obturation. The tooth was then restored with a fiber post and composite resin. At the 2.5-month follow-up, the patient was completely asymptomatic, and the radiograph displayed evidence of periradicular healing. In this case, robotic technology proved effective and feasible for the endodontic retreatment of a mandibular second premolar, suggesting its potential for similar applications in other teeth where there is adequate inter-arch space. Further research is needed to simplify procedures for robot-assisted endodontic retreatment.