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*

Bone Morphogenetic Proteins(BMPs)belong to the Transforming Growth Factor beta(TGF-?)family and play pivotal roles in osteogenesis,induction,maintenance and repair of bone.Differentiation of osteoprogenitor mesenchymal cells and up-regulation of osteoblastic features depend on the expressing level of BMPs.Because of their osteogenic potential,BMPs have tremendous potentia l as therapeutic agents in healing fractures of bone,preventing osteoporosis,healing of spinal fusion,treating periodontal defects and enhancing bone formation around alloplastic materials implanted in bone.Some mature products have been invented and available in market.This article reviews available therapeutic preparations of BMPs,involving carriers implanted for slow release,closed local injection and gene therapy,and suggests future applications likely to develop from current investigations.

Objective The purpose of this study was to evaluate the relationship between the initial X-ray display and prognosis of intracapsular fractures of the proximal humerus, and to probe a new criterion which can accurately predict the prognosis of the fracture. Methods Between April 1999 and February 2004, 459 cases of intracapsular fractures of the proximal humerus were treated conservatively, among which 211 cases had completed at least 9 months of follow-up and their complete data were available(mean age, 54.2 years; minimum, 17 years; maximum, 81 years; 82 males, 129 females), all the patients were followed up for 1.7 years on the average (ranging from 9 months to 3 years). According to the original X-ray, the fractures were classified by Neer classification. There were 68 cases of one part fractures, 39 cases of two parts fractures, 59 cases of three parts fractures and 45 cases of four parts fractures. The original X-ray and that of at least 9 months postoperatively of every case were assessed by seven structured standards and studied the relationship between the standards and prognosis. The seven standards are listed as follow: Neer classification; the length of the medial side of proximal humerus; displacement between humeral head and shaft; displacement of greater tuberculosis relative to shaft; displacement of medial cortex in fracture site; glenohumeral dislocation and humeral head split. Results 79% of the cases with a length of the medial side of proximal metaphyseal less than 8 mm, and 84% case with medial cortex displacement over 2 mm and 68% of Neer four-part fractures have a poor prognosis. The prognostic significance of predictors were listed as follow: the medial cortex displacement more than 2 mm (accuracy, 0.85), the length of the medial proximal metaphyseal less than 8 mm (accuracy, 0.83), Neer four-part fractures (accuracy, 0.76), Neer three-part fractures (accuracy, 0.72), glenohumeral dislocation (accuracy, 0.64), head-split components (accuracy, 0.64), displa-cement of the head more than 10 mm (accuracy, 0.54). Conclusion The new criterion provides a precise pr-ognosis prediction for intracapsular fractures of the proximal humerus thus it may be helpful in selecting a proper procedure.