Decision Support for Removing Fractured Endodontic Instruments: A Patient-Specific Approach

Aim: instrumental fracture is a common endodontic complication that is treated by surgical or non-surgical removal approaches. However, no tool exists to help the clinician to choose between available strategies, and decision-making is mostly based on clinical judgment. Digital solutions, such as Finite Element Analysis (FEA) and Virtual Treatment Planning (VTP), were recently proposed in maxillofacial surgery to help in this regard. The aim of the present paper is to present a digital tool to choose between non-surgical and surgical strategies in a clinical situation of fractured instrument (FI). Material and methods: patient tooth data were recorded using cone beam computed tomography (CBCT). VTP was conducted using an application suited for medical images to segment and plan the procedure. FEA has been carried out using the Abaqus software according to published material properties. Five models have been created: the initial state of the patient, two non-surgical removal strategies using a low or high root canal enlargement, and two surgical removal strategies using a 3-or 6-mm apicoectomy. Resuls: Results of the VTP found a risk of perforation for the non-surgical strategies and a sinus proximity for surgical ones. FEA identified the lowest mechanical risk for the 3-mm apicoectomy strategy. A 3-mm apicoectomy approach was finally chosen and performed. Conclusion: this digital approach could offer a decision tool for the instrument removal by planning the treatment and predicting the mechanical impact of each strategy.