恒牙根尖区解剖结构对根管治疗的影响

根管治疗的目的是彻底清除根管内感染物质,并严密充填根管,从而预防或治愈根尖周病变.恒牙根尖区解剖结构复杂,形态多样的根尖孔、弯曲根管、侧副根管等会对根管治疗各步骤产生影响,增加治疗难度,影响治疗效果.本文就恒牙根尖区解剖结构对根管治疗影响的研究进展进行综述.     

根管数目和形态的识别

根管治疗是通过机械和化学的方法彻底清除根管内的牙髓组织、细菌及其代谢产物并严密充填根管，达到预防根尖周病发生和促进根尖周病愈合的目的。根管预备和根管充填是根管治疗中的两个关键步骤。根管预备和充填的效果受许多因素特别是根管解剖因素的影响。治疗时可以通过多种诊断方法确定根管的数目并判断根管形态，再根据不同的根管形态制定相应的预备和充填策略，以使患牙获得良好的治疗效果。[第一段]     

现代根管预备技术

根管预备是决定根管治疗质量的关键步骤．其目的是彻底清除根管系统内的有机残渣、微生物和感染牙本质．成形根管至根尖部的牙本质一牙骨质界处．预备成遵循原有根管形态的流畅锥形以利于根管冲洗、消毒和严密的三维充填。     

根管治疗技术规范与疗效评价标准

根管治疗术是牙髓病和根尖周病治疗的基本方法和最佳选择。根管治疗术通过彻底清除根管内的炎性牙髓和感染坏死物质,成形根管,严密充填根管,以去除根管内容物对根尖周围组织的不良刺激,防止根尖周病变发生,促进根尖周病变愈合。     

根管治疗工作长度确定之惑及解决之道

牙髓根尖周疾病是一类细菌感染性疾病,疾病晚期细菌常定植于整个根管系统。临床治疗该类疾病的主要方法是根管治疗术,彻底清除根管内感染是该技术的核心,也是取得治疗成功的关键,其中准确的根管工作长度是彻底清除根管内感染的前提和保证。但如何准确地确定根管工作长度,尤其是确定根尖止点的位置一直是牙髓专科医生讨论的热点话题,并常常给许多临床医生造成疑惑。本文就牙齿根尖解剖结构的复杂性、根尖止点确定存在的疑惑以及根管工作长度确定方法作简要介绍。     

根管系统封闭性的影响因素及其检测方法

根管治疗术是牙髓病和根尖周病常见的治疗方法,术后严密封闭根管系统可以切断根尖周组织再感染途径,确保根管治疗的远期疗效。如果根管封闭性欠佳则容易引起病原微生物及其代谢产物经过封闭材料与根管壁之间的微渗漏(包括冠方和根尖区)使根尖周组织再感染导致根管治疗失败。可见严密封闭根管系统至关重要。目前检测根管封闭性的方法较多,但关于根管系统封闭性的影响因素和检测根管封闭性的方法尚缺乏较系统的阐述。本文将影响根管封闭性的因素及检测和评价根管封闭性的方法进行综述,为检测根管充填质量和评估远期疗效提供借鉴和参考。     

感染根管的治疗难点和对策

微生物感染是牙髓根尖周疾病发生和发展的根本原因,也是根管治疗失败的罪魁祸首.因此彻底清除根管系统内的感染物质,预防根管系统再感染,是保证根管治疗成功与否的关键.在临床根管治疗过程中,口腔环境定植细菌种类的多样性、牙髓组织环境的特殊性、根管系统解剖的复杂性以及治疗方法 的局限性,使得预防口腔微生物对根管系统的污染以及感染...     

根管充填技术的研究进展

根管治疗术是牙髓病和根尖周病最有效、最根本的治疗方法。根管治疗的最终步骤是严密充填根管系统,以防止根尖周组织再感染。牙胶是目前较理想的根管充填材料。本文对目前临床应用的不同根管充填方法进行综述,并对其临床应用效果作一评价。     

侧支根管充填

根管充填是根管治疗中的重点及难点,要求在彻底去除病原刺激物的基础上进行严密的充填。侧支根管为发自主根管通向牙周膜的细小分支,多发生于根尖1/3。由于其高发生率及预备清理的困难性,侧支根管及其他侧副管对于根管治疗疗效的影响一直是临床医生及研究者关注的核心问题。热牙胶充填技术在侧支根管充填的多项研究中均表现出突出优势,但尚未获得充分的临床证据来证实其疗效。文章将就侧支根管的解剖、充填必要性及充填方法等做一简介。     

顽固感染根管内粪肠球菌的致病机制及其控制方法进展

根管治疗是治疗牙髓感染的常用方法。成功的根管治疗依赖于良好的根管预备、冲洗消毒以及对三维根管系统的严密充填,其中通过清除根管系统内感染生物膜、细菌毒素以防止高度复杂的根管系统再次感染是根管治疗成功的关键。本文从根管内严苛环境下粪肠球菌的致病机制、根管顽固感染的根尖周组织炎症与局部免疫、感染根管控制方法进展等方面,对这一主题进行阐述。     

Deposition of calcified tissue around an overextended gutta-percha cone: case report

CASE REPORT: Root canal treatment was performed in a mandibular right second premolar with a periapical lesion and apical resorption. The root canal was prepared with K-files using the step-back technique and 3% NaOCl as an irrigant; during obturation gross overfilling of gutta-percha occurred. The tooth was permanently restored with a post and core along with a crown. Although healing of the periapical lesion occurred and the patient reported that he was symptom-free, the tooth was extracted after 4 years because of a subgingival root fracture. Following extraction the tooth was examined with SEM. The examination revealed the presence of newly formed calcified tissue at resorption sites on the root apex. This newly formed tissue extended from the surface of the root around the apex to the extruded gutta-percha cone to which it was well adapted, forming a bridge between the cone and the root.     

The Study of Calcium Phosphate Cement Filling Root Canal for Promoting Apical Closure

目的探索磷酸钙水门汀用作根充材料，促进根尖孔闭合的可行性。方法以三只犬为实验对象，人为造成根端开放后，采用磷酸钙水门汀充填根管，以氢氧化钙、羟基磷灰石糊剂作对照，于术后4、12、20周处死动物，组织学观察根尖孔闭合及根尖周修复过程。结果磷酸钙水门汀充填根管12周，根尖即有均质的钙化组织形成；20周时，根尖孔完全被钙化组织封闭，且根尖周组织炎症反应逐渐减弱至消失。对照组未能完全封闭根尖孔。结论磷酸钙水门汀与软硬组织有良好的相容性，具有促进根尖孔闭合的生物学作用。     

Apical limit of root canal instrumentation and obturation, part 1. Literature review

One of the major controversies in root canal therapy concerns the apical limit of instrumentation and obturation. The results of longitudinal prognostic studies, basic anatomical knowledge of the apical third of the root canal, and the histological pulp reaction to caries progression demonstrated the presence of a vital apical pulp remnant, even in the presence of a periapical lesion. Finally necrosis and bacteria establish themselves in the periapical lesion. All valid prognosis studies confirm the practice of staying short of the apex with a homogeneous obturation to obtain the highest success rate of 90-94% (when done by or under supervision of specialists; results in the general population had a failure rate greater than 50%). The location of the apical foramen(ina) related to root canal treatment most frequently ends short of the apex, often by several millimetres.     

关于根管系统严密封闭的研究现状

根管治疗术完成后根管系统冠根方的严密封闭可清除根管内绝大部分感染源，彻底切断感染途径，确保根管治疗术的远期疗效；而冠方和（或）根方封闭不良，病原微生物及其代谢产物可通过封闭材料与根管壁之间的微隙渗漏进入根尖周组织导致根管治疗术失败。本文就冠根方封闭效果与根管治疗术远期疗效的相关性，冠方与根方封闭的关系及其影响因素，根管封闭的研究方法等方面的研究现状作一综述。     

Electrical impedance measurements of root canal length

Abstract Electronic methods are now widely used during endodontic treatment for the assessment of root canal length. These commonly measure the electrical resistance or impedance between the root canal and the buccal mucosa. A number of studies have been undertaken to determine the accuracy of commercially available instruments. The aims of this investigation were to determine the electrical impedance characteristics of the root canal and periapical tissues in vivo, measure the changes relative to the distance of an endodontic instrument from the apical constriction and propose an equivalent circuit modelling the periapical tissues. The length of the root canals of 20 previously untreated teeth were determined using radiographic and electronic methods. Minimal canal preparation was carried out and measurements were made with a size 10 K-Flex file. A microprocessor-controlled LCR analyser was used to measure the electrical impedance characteristics of each root canal. The instrument measured the series and parallel resistive (Rs, Rp) and capacitance (C$, CP) component of the tissues at two test frequencies, 100 Hz and 1 kHz. Measurements were made for each root canal when the diagnostic file was placed at the apical constriction and repeated when the file was withdrawn to -0.5, - 1.0, - 1.5, -2.0 and -5.0 mm from the foramen. Readings were taken for each canal after the canal had been dried with paper points, and flooded first with deionisecl water and then with sodium hypo-chlorite. The root canals were then prepared, cleaned and obturated using standard endodontic procedures. The LCR analyser selected the series resistance component as the major measurement parameter. There was a clear increase in series resistance (Rs) with increasing distance from the radiographic apex for dry canals and those containing deionised water and sodium hypochlorite. The mean resistance for dry canals was markedly higher than for those containing fluid, ranging from 22.19 kd to 92.07 kω in comparison with 9.32 kω to 12.10 kω for deionised water and from 7.46 kω to 8.92 kω for canals containing sodium hypochlorite. There was a marked change in the series and parallel resistive component with distance from the apex, suggesting a complex relationship between the impedance of the smear layer and bulk dentine. The impedance characteristics of a root canal were a complex electrical network comprising resistive and capacitive series and parallel elements.     

Continued root formation of a pulpless permanent incisor following root canal treatment: a case report

AIM: To present a case of a pulpless permanent incisor that continued root formation following root canal treatment. SUMMARY: A healthy 8-year-old girl with a history of dental trauma resulting in a coronal fracture involving enamel, dentine and pulp was referred by her general dental practitioner for treatment and evaluation of tooth 21. The tooth had a necrotic pulp and periapical rarefaction was evident radiographically. The canal was prepared, dressed with Ca(OH)2 and then filled with a rolled gutta percha cone and Roth's root canal sealer. A radiograph exposed eight years post-treatment, showed evidence of continued apical formation. KEY LEARNING POINTS: *Teeth with necrotic pulps and periapical rarefaction may show evidence of continued apical formation after root canal treatment. *Hertwig's epithelial root sheath may be more resistant than expected to trauma and infection.     

A histobacteriological assessment of nonvital teeth after ultrasonic root canal instrumentation

Abstract The purpose of this study was to evaluate and discuss the bactericidal effect of ultrasound when applied in the root canal of teeth with necrotic pulp and periapical lesions. Twenty newly extracted teeth were instrumented with an ultrasonic unit and K-files using 0.5% sodium hypochlorite as irrigating solution. Compacted debris and micro-organisms were frequently observed in the apical region and in dentinal tubules of the root canal wall. Overinstrumentation that sometimes occurred led to contamination of the periapical lesions with micro-organisms and debris from the root canal.