The adaptation of mechanically softened gutta-percha to the canal walls in the presence or absence of smear layer: a scanning electron microscopic study

The objective of this study was to compare the adaptation of mechanically softened gutta-percha to the root canal wall in the presence and absence of smear layer. The root canals of 20 freshly extracted human maxillary incisors were cleaned and shaped. Prior to obturation, 10 root canals were irrigated with 20 ml of 50% citric acid followed by 20 ml of 5.25% sodium hypochlorite. All canals were obturated with mechanical compaction of gutta-percha and AH-26 sealer. After 72h, each tooth was fractured in half. Scanning electron microscopy demonstrated that the sealer had formed a continuous layer in contact with the canal walls, becoming progressively thinner towards the apex. The sealer pentrated into the dentinal tubules along with projections of gutta-percha only in those teeth without smear layer.     

Florid cemento‐osseous dysplasia mimicking apical periodontitis: A case report

Cemento‐osseous dysplasia may present as a focal, periapical or florid lesion in the mandible or maxilla. The lesion may sometimes appear similar to peri‐radicular lesions on a periapical radiograph. This report presents a case with irreversible pulpitis and root resorption as well as a mixed radiolucent/radiopaque lesion around a mandibular molar tooth root. Root canal treatment was performed and because of the radiographic signs of root resorption and the patient's fear of having a malignant disease, periapical surgery was also performed. The histopathology report confirmed the presence of florid cement‐osseous dysplasia which was mimicking apical periodontitis. Follow‐up radiography 12 months after the surgery illustrated complete healing of the radiolucent area.     

An unusual case of root perforation caused by surgical trephination

AIM: To present the diagnosis and management of an unusual case of root perforation caused by surgical trephination. SUMMARY: A root perforation caused by surgical trephination on a maxillary lateral incisor with diagnosis of symptomatic chronic periradicular periodontitis was managed with standard root canal preparation and filling with thermoplasticized gutta-percha. Recall radiographs up to 1 year revealed healing of the periapical lesion. *During surgical trephination, there is risk of damaging anatomical structures surrounding the tooth as well as the tooth itself. *Root perforation caused by trephination was successfully managed by standard canal preparation and filling with thermoplasticized gutta-percha.     

根管内牙胶充填材料去除方法和效果

根管治疗术是目前牙髓病及根尖周病最为有效的治疗方法,在临床上广为应用。但根管治疗失败仍时有发生,这就需要去除原有充填材料,重新进行根管预备、消毒和充填。牙胶是目前应用最为普遍的充填材料。文章将对根管再治疗过程中原有牙胶充填材料去除的方法、效果及安全性做一概述。     

�����������������ȥ��������Ч��

??The root canal therapy is the most effective treatment for pulpal and periapical disease??but failure occurred occasionally. Root canal retreatment is the best choice to save the teeth at this moment. The success of root canal retreatment depends highly on complete removal of previous root filling material and infection tissue??and formation of tight three-dimensional closure. This paper will discuss the method and effectiveness of intracanal gutta-percha removing.     

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.     

Limitations of previously published systematic reviews evaluating the outcome of endodontic treatment

The aim of this work was to identify the limitations of previously published systematic reviews evaluating the outcome of root canal treatment. Traditionally, periapical radiography has been used to assess the outcome of root canal treatment with the absence of a periapical radiolucency being considered a confirmation of a healthy periapex. However, a high percentage of cases confirmed as healthy by radiographs revealed apical periodontitis on cone beam computed tomography (CBCT) and by histology. In teeth, where reduced size of the existing radiolucency was diagnosed by radiographs and considered to represent periapical healing, enlargement of the lesion was frequently confirmed by CBCT. In clinical studies, two additional factors may have further contributed to the overestimation of successful outcomes after root canal treatment: (i) extractions and re-treatments were rarely recorded as failures; and (ii) the recall rate was often lower than 50%. The periapical index (PAI), frequently used for determination of success, was based on radiographic and histological findings in the periapical region of maxillary incisors. The validity of using PAI for all tooth positions might be questionable, as the thickness of the cortical bone and the position of the root tip in relation with the cortex vary with tooth position. In conclusion, the serious limitations of longitudinal clinical studies restrict the correct interpretation of root canal treatment outcomes. Systematic reviews reporting the success rates of root canal treatment without referring to these limitations may mislead readers. The outcomes of root canal treatment should be re-evaluated in long-term longitudinal studies using CBCT and stricter evaluation criteria.     

Dental Pulp Regeneration Induced by Allogenic Mesenchymal Stromal Cell Transplantation in a Mature Tooth: A Case Report

IntroductionCellular therapy constitutes a new therapeutic alternative in regenerative endodontics. In this case report, we evaluated the capacity of allogeneic mesenchymal stromal cells (MSCs) to induce dental pulp and apical bone regeneration in a tooth previously endodontically treated.MethodsA healthy 55-year-old female patient consulting for swelling and a sinus tract associated with tooth #8 was referred for an endodontic evaluation. Previously, tooth #8 had undergone root canal treatment and apical resection and had no response to thermal or electric pulp testing. Radiographically, tooth #8 showed root canal treatment, a cut apex angle, and periapical radiolucency. The root canal was recleaned and shaped, and calcium hydroxide was used as an interappointment medication. Cryopreserved allogeneic bone marrow MSCs were thawed, expanded, incorporated into preclotted platelet-rich plasma, and implanted into the pulp cavity of tooth #8. The cervical part of the canal was sealed with bioceramic cement and a composite.ResultsAfter 14 months of MSC transplantation, tooth #8 showed sensitivity to cold and electric pulp tests. Radiographic and cone-beam computed tomographic imaging showed signs of increased periapical bone density, healing of the periapical lesion, and almost complete apical remodeling.ConclusionsThis case report shows periodontal bone formation, apex remodeling, and dental pulp regeneration induced by allogeneic MSC transplantation in a mature nonvital tooth. Allogeneic MSCs may constitute a first-line therapy in regenerative endodontics.     

老年患者根管充填GuttaFlow的临床观察

目的：评价常温流动牙胶GuttaFlow根管充填的疗效。方法：65名老年牙髓病患者,83颗患牙,165根根管。镍钛旋转器械根管预备成0．06锥度根管,采用常温流动牙胶GuttaFlow配合主牙胶尖技术根管充填。根管充填后即刻根尖片按照评价标准评分,并随访术后反应。结果：A级97根;B级52根;C级16根;术后胀痛15例。结论：常温流动牙胶GuttaFlow配合主牙胶尖技术根管充填具有充填效果好、不良反应小、操作省时的特点,是一种非常适合老年牙髓病患者的充填方法。     

Repair of Extensive Apical Root Resorption Associated with Apical Periodontitis: Radiographic and Histologic Observations after 25 Years

Introduction

Root resorption is a frequent finding in teeth with apical periodontitis. In cases of severe apical periodontitis, root resorption may involve not only cementum but also dentin. Resorbed tooth structures can only be repaired with cementum because stem cells in the periradicular tissues are not capable of differentiating into odontoblasts. This article reports the repair of extensive apical root resorption associated with apical periodontitis 25 years after treatment.

Methods

A 51-year-old man presented with pulp necrosis and symptomatic apical periodontitis in tooth #7. The periapical radiograph showed a large radiolucent periradicular lesion and severe root resorption. Nonsurgical root canal therapy was performed. Twenty-five years after treatment, a crown fracture developed, and the tooth could not be restored. The periapical radiograph revealed complete healing of the previous apical periodontitis lesion and restoration of the resorbed root structure. The tooth was removed and examined histologically.

Results

The apical canal was almost completely filled with a cementumlike tissue with some strands of entrapped vital uninflamed connective tissue. Areas of cementum and dentin resorption in the apical third were repaired by a combination of cellular and acellular cementum to which periodontal ligament fibers were attached.

Conclusions

Root resorption caused by apical periodontitis can be restored almost to its normal structure after adequate nonsurgical root canal treatment that succeeded in controlling infection. The mechanisms behind this process are not clear but probably involve signaling pathways regulating root development, cell-cell and cell-matrix interaction, and morphogens.     

23例27个粗大根管的根管治疗及修复临床观察

目的 :观察 2 3例 2 7个粗大根管的根管治疗及修复效果并总结治疗经验。方法 :对 2 7个根管未完全发育成形的残根、残冠进行根管治疗及修复 ,随访 2年观察治疗效果。结果 :2 7个粗大根管在根管治疗过程中 ,2 3个牙经化学根管预备后即产生良好的根充效果 ,3个牙仅作机械根管预备而未作化学预备的患牙首次根管治疗失败 ,采用化学预备重新根充效果良好 ,1个牙反复出现瘘管而拔除。自制牙胶尖未发生超充情况。修复后有 7个牙出现根折 ,其余均修复效果良好。结论 :利用化学方法对粗大根管进行预备是必须的 ,采用自制牙胶尖进行根管充填能形成良好的根尖封闭。修复的关键在于尽量保留牙体组织。牙颈部需形成“颈箍” ,肩台必须位于正常牙体组织上。     

单尖法和热牙胶法根管充填根尖封闭性能的比较研究

目的 比较3种封闭剂AH-Plus, iRoot SP和GuttaFlow2分别配合单尖法充填和热牙胶充填的根尖封闭性能。方法 选取近期拔除的70颗单根管前磨牙,截冠后采用Waveone gold系统预备至P#,随机分为6个实验组(每组10颗)和2个对照组(每组5颗)。分别行单尖法充填和热牙胶充填,即AH-Plus单尖法组(A1组),AH-Plus热牙胶组(A2组),iRoot SP单尖法组(B1组),iRoot SP热牙胶组(B2组),GuttaFlow2单尖法组(C1组),GuttaFlow2热牙胶组(C2组),阳性对照组(D组)和阴性对照组(E组)。将充填完成的牙齿进行染料渗透实验后,通过纵切片法检测根尖的微渗漏情况。结果 A1组微渗漏值最大,B2组微渗漏值最小,同种封闭剂下单尖法充填和热牙胶充填根尖封闭性差异无统计学意义(P>0.05),同种充填技术下3种封闭剂的封闭性差异无统计学意义(P>0.05)。结论 3种根管封闭剂均不能完全封闭根管,单尖法充填和热牙胶充填在根尖封闭效果上无显著差异。     

Regenerative Endodontic Procedures for Traumatized Immature Permanent Teeth with Severe External Root Resorption and Root Perforation

External root resorption (ERR) is often a complication of traumatic injury to the teeth. Traditionally, external inflammatory root resorption is treated with calcium hydroxide. The outcome of ERR, especially replacement resorption, is unpredictable. The purpose of the present case report was to describe regenerative endodontic procedures (REPs) for 1 replanted avulsed tooth with severe external root resorption and root perforation (tooth #9) and 1 extruded tooth (tooth #8). A 9-year-old girl was referred for the treatment of teeth #8 and #9 4 months after the initial trauma. Clinical examination showed that tooth #9 had a sinus tract present near the periapical area, was tender to percussion and palpation, and did not respond to pulp sensibility tests. Tooth #8 responded to pulp sensibility tests. Periapical radiographic and cone-beam computed tomographic examination showed that tooth #9 had a periapical radiolucent lesion and severe ERRs with a root perforation. Tooth #9 was diagnosed with a necrotic pulp and symptomatic apical periodontitis. Regenerative endodontic procedures (REPs) were initiated. Tooth #8 became nonresponsive to pulp sensibility tests and developed a periapical lesion 12 months after REPs of tooth #9 and was also treated with REPs. The clinical symptoms and apical lesions resolved for both teeth after REPs. The severe ERRs were arrested, and root perforation was repaired for tooth #9. Teeth #8 and #9 underwent canal obliteration by hard tissue formation after REPs and were in function at 18 months and 30 months, respectively. REPs may be used to manage traumatized immature permanent teeth with a necrotic pulp and apical periodontitis associated with severe ERR and root perforation.     

Calcium hydroxide barrier over the apical root-end of a type III dens invaginatus after endodontic and surgical treatment

AIM: To report the simultaneous endodontic and surgical treatment of a tooth associated with Oehlers type III dens invaginatus and a persistent periapical lesion, which comprised root-end resection, root-end filling and application of a calcium hydroxide barrier placed on the resected dentine surface. SUMMARY: Three root canals were identified in a tooth with a type III dens invaginatus, which presented with a necrotic pulp, wide foraminal opening and extensive periapical lesion, and with a previous history of acute abscess, intracanal exudate and fistula. After root canal preparation followed by intracanal application of calcium hydroxide pastes, the clinical-pathological status persisted. After periapical curettage and root-end resection, the root canals were filled, followed by root-end filling with Sealer 26 mixed with zinc oxide powder to a clay-like consistency. Calcium hydroxide paste was then applied over the exposed dentinal surface forming a covering over the root apex. At the 20-month follow-up examination the patient had no symptoms and no fistula; advanced periapical bone repair was obvious on the radiograph. KEY LEARNING POINTS: Because of the variable morphology and extent of invagination, type III dens invaginatus represents a challenge for conventional treatment, often leading to the need for a surgical approach. Sealer 26 thickened with zinc oxide powder provided satisfactory clinical properties for use as a root-end filling material. Application of a calcium hydroxide barrier over the resected root-end is a potential treatment option to encourage tissue repair.     

Ex vivo evaluation of the accuracy of two electronic apex locators during root canal length determination in primary teeth

Aim To evaluate ex vivo the accuracy of two electronic apex locators during root canal length determination in primary incisor and molar teeth with different stages of physiological root resorption. Methodology One calibrated examiner determined the root canal length in 17 primary incisors and 16 primary molars (total of 57 root canals) with different stages of root resorption based on the actual canal length and using two electronic apex locators. Root canal length was measured both visually, with the placement of a K‐file 1 mm short of the apical foramen or the apical resorption bevel, and electronically using two electronic apex locators (Root ZX II – J. Morita Corp. and Mini Apex Locator – SybronEndo) according to the manufacturers’ instructions. Data were analysed statistically using the intraclass correlation (ICC) test. Results Comparison of the actual root canal length and the electronic root canal length measurements revealed high correlation (ICC = 0.99), regardless of the tooth type (single‐rooted and multi‐rooted teeth) or the presence/absence of physiological root resorption. Conclusions Root ZX II and Mini Apex Locator proved useful and accurate for apex foramen location during root canal length measurement in primary incisors and molars.     

Differences in the confluence of mesial canals in mandibular molar teeth with three or four root canals

Aim  To investigate the correlation between number of root canals and their confluence in mandibular molar teeth.
Methodology  A total of 553 first and 383 second mandibular molars were root filled between the beginning of 1997 and the end of 2006. Access cavities were prepared and the pulp chamber floors were carefully inspected with an endodontic explorer under magnification of 4×. After negotiating the root canal system, the 'straightest' canal of each root was instrumented. A gutta-percha cone was placed in the canal and a small file (08 or 10) was inserted to working length and then removed in all other canals. The gutta-percha cone was removed and inspected for notches indicating the presence of confluences. If it was not possible to probe completely one or more canals, the canal confluences were classified as 'not determined' (ND) if there was no sign of confluence; if a notch was present canals were considered confluent. For each tooth, the number of root canals and the presence of confluences were recorded. To test whether there was a difference in frequency of confluences between teeth with three and four root canals the chi-squared analysis with Yates' continuity correction was performed.
Results  The frequency of a confluence in mesial canals of first molars was 56% in teeth with three root canals and 34% in teeth with four canals. In second molars, it was 67 and 41%, respectively. Differences in the frequency of confluences in teeth with three and four root canals were statistically significant both in first and in second molars.
Conclusions  A greater incidence of confluent canals occurred in teeth with three rather than with four root canals both in first and second mandibular molars.     

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.     

Tissue response to an epoxy resin-based root canal sealer

Abstract— Thc objective of the present study was to evaluate two different types of root canal sealers: AH Plus (an epoxy resin-based sealer) and Fill Canal (a zinc oxide-eugenol based sealer). A total of 34 root canals with vital pulp from dogs' premolars were used. After instrumentation, the root canals were filled with gutta-percha and AH Plus or gutta-percha and Fill Canal sealers using a classical technique of lateral condensation. After histological processing, the sections were stained with hematosylincosin or Mallory's trichrome stain. Inflammatory cells or areas of necrosis were not associated with AH Plus. Hard tissue formation apically to the material was observed in 14 specimens. The Fill Canal sealer presented an inflammatory response of moderate intensity in the periapical region, mainly adjacent to the material.     

根管超充引发急性根尖周炎的临床研究

目的探讨根管超充与引发急性根尖周炎的关系。方法收集根管充填后1周内出现急性根尖周炎的患者60例,拍摄X线牙片确定为根管糊剂或牙胶尖超充。根据临床症状将患者分为轻症和重症,测量超充部分的牙胶尖长度或糊剂面积。治疗时完全去除根管内充填物,必要时予以调牙合,每日换药直至症状完全消失,记录所需时间。结果轻症和重症患者的牙胶尖平均超充长度分别为1.01 mm和1.79 mm,糊剂平均超充面积分别为2.45 mm2和8.26 mm2;牙胶尖超充组轻症和重症分别有13例和21例,糊剂超充组轻症和重症分别有18例和8例;牙胶尖超充组和糊剂超充组临床症状完全消失所需时间分别为3.56 d和6.19 d。以上数值组间均有统计学差异（P<0.05）。结论超充量较大则患者临床症状较重;牙胶尖超充患者的临床症状较重但症状完全消失所需的时间较短。     

根尖感染的控制技术

根管治疗术是治疗牙髓病、根尖周病的首选方法,其目标是彻底清除根管系统内的感染,并严密充填以防止再感染。由于根管系统解剖复杂性和感染多样化的存在,使得常规化的根管治疗常常难以彻底清除感染,尤其是根尖部（包括根管内根部1/3和根尖外组织）。根尖部的位置隐蔽,根尖分歧、根管侧支等解剖结构多,治疗器械难以达到,感染控制难度大。本文就根尖部感染的特点和难点进行总结,并对根尖内和根尖外的感染控制策略进行简要介绍,包括根尖部的预备方法,根管消毒和严密根管充填的方法等。