A Novel Surgical Approach for the Successful Removal of Overextruded Separated Endodontic Instruments

Endodontic procedures can result in various complications. Separation of the endodontic instrument is a common complication of incorrect use or overuse of the instrument. However, a separated endodontic instrument may hinder cleaning and shaping during endodontic treatment procedures, which can potentially impact prognosis. Therefore, it is necessary to manage this complication by removal of the separated instruments from inside the root canal. Although several devices are used, nonsurgical removal for retreatment remains difficult. We report the case of a failed attempt to manage a separated endodontic instrument nonsurgically by a private dentist, which resulted in extrusion of the instrument beyond the root apex and its migration into the mandible. We describe a novel surgical approach involving intentional tooth replantation combined with alveolar osteotomy. There have been few reports on the management of separated endodontic instruments that were pushed out beyond the root apex. Our novel surgical approach suggests a technique for the potential removal of a separated endodontic instrument extruded beyond the root apex.     

Il ruolo della strumentazione meccanica nei ritrattamenti endodontici

Objectives

Endodontic retreatments are performed when endodontic therapy fails and the tooth is considered restorable. They include orthograde, surgical, and combined approaches. The primary objective of orthograde retreatment is the complete removal of the old filling material from the root canal. The purpose of this paper is to describe an orthograde endodontic retreatment technique performed with specific mechanical instruments made of nickel-titanium (NiTi).

Materials and methods

For retreatment, the root canal filling can be removed with traditional methods, such as heat carriers, Largo or Gates burs, and hand-held steel instruments, or newer methods, such as ultrasonic inserts, laser tips, and NiTi files (manual or mechanical). The orthograde retreatment technique presented here uses specific NiTi endodontic rotary instruments (Mtwo R^®). We describe its use in two cases involving retreatment of teeth 4.6 and 2.5, whose root canals had been filled using thermoplastic gutta-percha, plastic carrier and endodontic sealer, and a single gutta-percha point.

Results and conclusions

The success of orthograde endodontic retreatment depends on many factors, including correct and complete removal of old filling material from the root canal. The specific NiTi endodontic rotary instruments (taper .05) we used are very sharp at the level of the blades and the tip, and they allow rapid, safe removal of commonly used endodontic filling materials, even in the presence of a plastic carrier. As illustrated by the two cases presented, we used NiTi endodontic rotary instruments specifically designed for retreatment in the coronal two thirds of the canal, manual instruments in the apical third, and simultaneous technique after the filling material had been removed. This approach allowed acceptable preservation of the original anatomy of the canal and effective sealing by the new filling material.     

5种手持根管器械预备弯曲人工根管的效果

目的 比较５种手持根管器械的成形能力。方法 用光学显微镜观察５种手持根管器械常规法预备弯曲人工根管后的根管形态变化。结果 所有标本未发现根尖拉开、肘部形成和穿孔。Ｋ－Ｆｌｅｘ组有７５％的标本出现台阶，台阶的出现与在部树脂屑栓的形成有很密切的关系。Ｋ－Ｆｌｅｘ组和Ｈ锉的组的根尖偏移较大，与Ｋ针组比较，有显著性差异，其余各组之间无显著性差异，其余各组之间无显著性差异。结论 通过综合评价５和睥持根管器械     

The use of ultrasonic endodontic instrumentation in the re-treatment of a paste-filled endodontic tooth

A technique using ultrasonic endodontic instruments in re-treating hard-paste--filled root canals is presented. The technique is time-consuming but may eliminate the necessity for a surgical approach in the re-treatment of paste-filled teeth.     

A combined post, core, and endodontic endosseous implant. Case report

A hyperextended chrome-cobalt post and core also used as an endodontic endosseous implant served to stabilize a short mobile root and to provide for placement of a porcelain veneer metal crown. The technique is not complicated and does not require instruments other than those for routine endodontic treatment and for the construction of the post and core.     

根管治疗技术在浙江省临床应用的现状调查

目的：调查浙江省多家医院口腔内科医师,分析根管治疗术在浙江省的应用现状。方法：随机抽查浙江省各级医院口腔内科医师。进行问卷调查,内容包括牙髓病首选治疗方法和考虑因素,根管充填术所采用的具体器械、材料等。采用SPSS12．0统计软件包进行描述性分析以及Mann—Whiteney U检验。结果：共有76家单位的410名医师接受调查,回复率为91．1％。其中93．5％的口腔医师首选根管治疗术治疗牙髓病,认为其对牙髓病治疗的远期疗效最佳;90．2％使用手用器械进行根管预备,在前牙主要采用常规法,在后牙主要采用逐步后退法;88．3％选择H202作为根管冲洗液;超过一半的调查者选择樟脑酚作为根管消毒剂;77．6％的口腔医师选择冷侧压法进行根管充填,使用频率最高的充填材料是牙胶尖辅以碘仿糊剂：74．6％的口腔医师曾做过一次性根管治疗术。其中部分医师在术后使用了抗生素或激素。结论：浙江省口腔内科医师已广泛应用根管治疗术治疗牙髓病,但在具体的技术方法和材料器械的应用方面,需要不断学习提高和发展更新。     

镍钛根管器械机械性能的理解与评价

各种根管预备器械的机械性能差异与其化学成分、镍钛金属的晶相组成及镍钛预备器械的制造过程有关。掌握镍钛根管预备器械的机械性能和相关的金属性能将有助于临床医师了解根管预备器械的特性．以便于选择合适的器械进行根管预备。本视频讲座将总结各种镍钛根管预备器械的机械性能,包括传统超弹性镍钛器械和最新推出的马氏体和R相镍钛器械的弹性、抗扭力和抗疲劳等特性,同时也将讨论金属特性和热机械处理对器械机械性能的影响。     

Accidental ingestion and aspiration of root canal instruments and other dental foreign bodies in a French population

AIM: To determine the incidence of aspiration and ingestion of endodontic instruments in France during root canal treatment without using rubber dam. METHODOLOGY: Data was provided by two insurance companies representing 24,651 French general dentists over 11 years. The type and number of accidents per year, the number of dental items involved and the percentage of occurrence of either aspiration or ingestion were reported. The incidence of accidental aspiration or ingestion was calculated. The need for hospitalization to remove the endodontic instruments and other dental items was reported and compared using chi square tests. RESULTS: One endodontic instrument was aspirated and 57 were ingested. Forty-three other dental items were aspirated and 409 were ingested. For the endodontic instruments: the incidence of aspiration was 0.001 per 100,000 root canal treatments and the incidence of ingestion was 0.12 per 100,000 root canal treatments. The aspirated endodontic instruments and dental items required statistically more frequent hospitalization than the ingested items (P < 0.0001). The endodontic instruments did not require more frequent hospitalization than other dental items when aspirated (ns) and when ingested (ns). No fatal outcome was reported. CONCLUSION: The incidence of ingestion or aspiration of endodontic instruments was low even thought most general practitioners do not routinely use rubber dam. Use of rubber dam by general practitioners for endodontic procedures should be encouraged by stressing its advantages rather than the fear factor of accidents.     

Comparison of the Canal Master endodontic instrument and K-type files for enlargement of curved root canals

Twenty mandibular molars with 40 mesial curved root canals were instrumented with a circumferential technique using K files and the Canal Master instrumentation technique by junior dental students whose only endodontic experience had been completion of a preclinical endodontic course. Preoperative and postoperative radiographs were taken facially and mesially with instruments in place. The canals were evaluated radiographically for transportation 1 mm and 4 mm from the apex. The mesial roots were cross-sectioned at the same level. The sections were evaluated for roundness of the canal preparation. It was concluded that the Canal Master instrumentation technique transported the root canal less and produced rounder preparations than the K file circumferential technique. There appears to be a greater tendency for breakage with the Canal Master.     

根管治疗中75例器械折断的临床分析

目的：分析器械折断的原因,提出处理方法和预防措施。方法：对根管治疗中器械折断的病例进行归纳、总结、分析。结果：器械折断的发生率为２．６１％。断械以扩孔钻、根管锉和电动扩孔钻为主,占９０．７％。器械折断于上磨牙近颊根管和下磨牙近中根管者居多,占７０．７％。器械折断在根管中下段多见,占７０％。结论：发生断械的患牙经过适当处理,大多数因无临床症状而得以保存。     

Disposable carrier constructed with a fluoride tray and a mixing pad: an endodontic aid.

An endodontic file carrier is fabricated from disposable foam fluoride trays glued to a mixing pad. The carrier allows convenient retention and transfer of root canal instruments and is particularly useful when the clinician is utilizing a rotary handpiece canal-shaping technique with hand files and reamers.     

Apical crown technique to model canal roots. A review of the literature

The goals of endodontic therapy are to shape and clean the root canal system in order to receive a three-dimensional and hermetic filling of the entire endodontic space. The aim of this review is to analyze the development of the different canal shaping techniques from the manual stainless-steel instruments to the recently developed rotary Ni-Ti systems. The need to provide instruments of a suitable size to reach the apex of curved root canals drove the development of preparation techniques with a greater focus on the apical part. The Crown-Down technique involves the widening of the canal orifices with Gates-Glidden drills followed by the incremental removal of organic canal contents proceeding from the canal orifice to the apical portion using manual files. Files are used from larger to smaller with no apical pressure. Nevertheless, the term 'Crown-Down' does not define the technique in the strictest sense, nor does it provide a specific sequence for the use of instruments, but rather defines a way to use the instruments. The preparation of root canals has been revolutionised by the development of Ni-Ti alloys. The features of this alloy give instruments profound flexibility and allow the manufacture of more tapered instruments compared with traditional stainless-steel instruments. In the second part of this review, numerous examples are provided concerning the comparison between different Ni-Ti systems and their techniques for use. A Crown-Down approach provides certain advantages including early organic debris removal, the creation of a large reservoir for irrigating solutions, a straighter access to the apical region of curved canals, and greater precision with regard to the exact working length and apical size.     

镍钛根管器械切削性能研究进展

镍钛根管器械具有超弹性、柔韧性及形状记忆效应，是根管预备的首选器械，而镍钛器械的切削能力也一直是临床医生关注的重点。镍钛根管器械的切削性能受多种因素影响，国内外学者们也研究出一系列改进措施来提高镍钛根管器械的切削能力。文章从镍钛器械切削性能的自身影响因素、外界影响因素、检测方法及改进措施等方面做一简要综述。     

Endodontic retreatment: a rational approach to root canal reinstrumentation.

During nonsurgical endodontic retreatment, endodontic instruments are forced apically to remove the root canal filling material and regain canal patency. Undiscriminating burrowing down the canal in the apical direction may be fruitless and harmful. To avoid complications, the dentin overhanging the canal orifice must be removed and an unobstructed access established to the root filling material, so as to facilitate its removal. Reinstrumentation of the filled canal must take into consideration the nature of the filling material and the physical properties of endodontic instruments, as well as the dynamic aspects of canal preparation. This article discusses the mechanical considerations pertaining to root canal retreatment and outlines a step by step rationale approach to retreatment.     

An overview of the mechanical properties of nickel–titanium endodontic instruments

Differences in mechanical properties between endodontic instruments might be related to the chemical composition, phase constitution, or fabrication process of nickel–titanium (NiTi) endodontic instruments. An awareness and knowledge of the mechanical properties of NiTi endodontic files and their association with the metallurgical properties is useful for clinicians to understand the behavior of NiTi instruments in root canals and help them to make decisions regarding which instruments are appropriate for root canal therapy under certain clinical conditions. This review article summarizes the mechanical properties of NiTi endodontic instruments including the flexibility, torsional resistance, flexural resistance, and cyclic fatigue of the conventional superelastic NiTi instruments and the most recently developed novel NiTi instruments with martensite and R‐phase. The influence of the metallurgical properties and the thermomechanical processing on the mechanical properties are discussed.     

Guided Endodontic Access in Maxillary Molars Using Cone-beam Computed Tomography and Computer-aided Design/Computer-aided Manufacturing System: A Case Report

The aim of this study was to describe a guided endodontic technique that facilitates access to root canals of molars presenting with pulp calcifications. A 61-year-old woman presented to our service with pain in the upper left molar region. The second and third left molars showed signs of apical periodontitis confirmed by the cone-beam computed tomographic (CBCT) scans brought to us by the patient at the initial appointment. Conventional endodontic treatment was discontinued given the difficulty in locating the root canals. Intraoral scanning and the CBCT scans were used to plan the access to the calcified canals by means of implant planning software. Guides were fabricated through rapid prototyping and allowed for the correct orientation of a cylindrical drill used to provide access through the calcifications. Second to that, the root canals were prepared with reciprocating endodontic instruments and rested for 2 weeks with intracanal medication. Subsequently, canals were packed with gutta-percha cones using the hydraulic compression technique. Permanent restorations of the access cavities were performed. By comparing the tomographic images, the authors observed a drastic reduction of the periapical lesions as well as the absence of pain symptoms after 3 months. This condition was maintained at the 1-year follow-up. The guided endodontic technique in maxillary molars was shown to be a fast, safe, and predictable therapy and can be regarded as an excellent option for the location of calcified root canals, avoiding failures in complex cases.     

Hemisection of the mandibular molars and their use for orthodontic purposes

The results of a combined treatment of 41 patients with chronic periodontitis of lower molars are described. The four-stage technique of hemisection is presented in detail: (1), endodontic treatment of a preserved root; (2), crown reconstruction beneath the root in the form of the premolar; (3), separation of the afflicted root from intact ones using an improved set of minute instruments; (4), diseased root extraction. The recommendations are given to improve the orthopedic treatment.     

Mechanical preparation of root canals: shaping goals,techniques and means

Preparation of root canal systems includes both enlargement and shaping of the complex endodontic space together with its disinfection. A variety of instruments and techniques have been developed and described for this critical stage of root canal treatment. Although many reports on root canal preparation can be found in the literature, definitive scientific evidence on the quality and clinical appropriateness of different instruments and techniques remains elusive. To a large extent this is because of methodological problems, making comparisons among different investigations difficult if not impossible. The first section of this paper discusses the main problems with the methodology of research relating to root canal preparation while the remaining section critically reviews current endodontic instruments and shaping techniques.     

Evaluation of an ultrasonic technique to remove fractured rotary nickel-titanium endodontic instruments from root canals: an experimental study

The use of nickel-titanium rotary instruments in endodontic practice is increasing. One frequently mentioned problem is fracture of an instrument within the root canal. To date, there is no consistently safe and successful technique for removing these fractured instruments. This study evaluates the use of an ultrasonic technique to remove fractured rotary nickel-titanium instruments from narrow, curved canals in both simulated (resin blocks) and mesiolingual canals of extracted mandibular first molars. A technique using ultrasonic tips, combined with the creation of a "staging platform" and the use of the dental operating microscope, was consistently successful and safe at removing fractured rotary nickel-titanium instruments from curved root canals, when some part of the fractured instrument segment was located in the straight portion of the canal. When the fractured instrument segment was located entirely around the curve, the success rate was significantly decreased and major canal damage often occurred.     

The effect of ultrasonic root canal preparation on inflammatory root resorption

Abstract In recent years, ultrasonic endodontic instruments have been used for the cleansing and disinfecting of root canals. In the present study, inflammatory root resorption, itself an indication of the presence of bacteria in the dental root, was experimentally induced in monkey teeth. Root canals were subjected to ultrasonic endodontic preparation in order to investigate the antibacterial effects of this treatment method on the pulpal and periodontal tissues in vivo. Results were histologically evaluated using a morphometric technique, and revealed that ultra-sonication eliminated bacteria and inflammatory root resorption. Furthermore, it had no damaging effects on a healthy periodontal membrane. It is suggested that this mode of treatment may be of value in the elimination of bacteria inside those dentinal tubules otherwise inaccessible to conventional therapy.