Instrument separation is a critical complication during root canal therapy, impacting treatment success and long-term tooth preservation. The etiology of instrument separation is multifactorial, involving the intricate anatomy of the root canal system, instrument-related factors, and instrumentation techniques. Instrument separation can hinder thorough cleaning, shaping, and obturation of the root canal, posing challenges to successful treatment outcomes. Although retrieval of separated instrument is often feasible, it carries risks including perforation, excessive removal of tooth structure and root fractures. Effective management of separated instruments requires a comprehensive understanding of the contributing factors, meticulous preoperative assessment, and precise evaluation of the retrieval difficulty. The application of appropriate retrieval techniques is essential to minimize complications and optimize clinical outcomes. The current manuscript provides a framework for understanding the causes, risk factors, and clinical management principles of instrument separation. By integrating effective strategies, endodontists can enhance decision-making, improve endodontic treatment success and ensure the preservation of natural dentition.
Humans ; Root Canal Therapy/adverse effects* ; Consensus ; Root Canal Preparation/adverse effects*

AIM: The aim of this work is to investigate the protective effects of Ginsenoside Rb 1(Rb 1) on apoptosis induced by hypoxia /hypoglycemia and reoxygenation in cultured rat hippocampal neurons. METHODS: Apoptosis were measured by flow cytometry; Morphological changes and neuronal necrosis were examined under microscope; The leakage of lactic dehydrogenase(LDH) and the product of nitric oxide(NO) were measured. RESULTS: hypoxia /hypoglycemia cultures for 5 h and reoxygenation induced neuronal apoptosis and necrosis,and significantly increased the leakage of LDH and the product of NO. The effects were enhanced with the extending time of reoxygenation. Rb 1 could significantly decrease the percentage of neuronal apoptosis and necrosis, and reduce the leakage of LDH and the product of NO. CONCLUSION: Rb 1 had an effect of anti-neuronal apoptosis. This effect might be related to the inhibition of the activity of NO synthase and NO production.