根尖倒充填术微渗漏的研究进展

根尖倒充填术扩大了保留牙齿的适应证的范围,提高了患者的生活质量,但是对决定手术能否成功的关键因素—根尖倒充填微渗漏的研究结果仍然不统一。本文从根尖切除方法、根尖切除斜度、根尖切除后术区处理、根尖倒充填材料等方面加以综述。     

根管充填后根尖微渗漏的评估及预防方法

根管充填的作用在于封闭整个根管系统，封闭不严会造成根尖微渗漏导致治疗失败。根尖微渗漏是评价根管充填材料根尖封闭效能的常用指标，目前评估根尖微渗漏的主要方法包括：染色法、液体滤过(传输)法、电化学法、放射性同位素渗透法和细菌或内毒素渗透法等。Nd：YAG激光和Er：YAG激光照射后可有效预防根尖微渗漏。     

磨牙根尖切除术和倒充填术的临床疗效观察

目的观察根尖切除术和倒充填术在难治性磨牙牙髓病和根尖周病治疗中的临床疗效。方法选择41颗难治性牙髓病和根尖周病的磨牙,经常规根管治疗无效,进行根尖切除术和根尖倒充填术,术后随诊观察。结果本组41颗患牙,其中28颗手术治疗后无自觉症状且完全恢复功能,组织附着紧密。10颗患牙经治疗后咀嚼基本正常,瘘管消失,疼痛消失,根尖阴影缩小。临床成功率为92.68。结论根尖切除术和倒充填术在难治性磨牙牙髓病和根尖周病治疗中,具有满意的疗效。     

连续波热牙胶垂直充填术根尖微渗漏的研究

目的 评价连续波热牙胶垂直充填术在根充后3、7、30d的根尖微渗漏情况,并与根管冷侧压充填做比较.方法 将87颗单根人离体牙,常规根管预备,随机分为2组,S组43颗牙采用连续波热牙胶垂直根管充填术;L组44颗牙选用冷侧压根管充填术.2组根管充填后进行染色,分别在3、7、30d纵向劈开牙后,测量染色线长度并进行统计学分析.结果 S3d组,L3d组,S7d组,L7d组的染色线长度分别为2.13±2.13mm,3.50±2.05mm,5.36±3.58mm,3.58±2.95mm,统计学无显著性差异(P＞0.05).S30d组和L30d组的染色线长度分别为4.73±3.90mm,7.33±5.05mm,S30d比L30d短,但统计学没有差异(P＞0.05).结论 连续波热牙胶垂直充填术在根尖微渗漏方面,短期内与冷牙胶侧压充填术无明显差异.长期(1个月以上)优于冷牙胶侧压充填术,但统计学无差异.     

玷污层和充填技术及材料对根尖微渗漏的影响

临床上根尖微渗漏是一个常见的引起根管治疗失败的原因.影响根尖微渗漏的因素较多,本文就玷污层、充填技术和充填材料对根尖微渗漏的影响进行概述.     

应用螺纹钉对根管充填后根尖微渗漏的影响

目的 探讨用螺纹钉挤压根管充填材料，对根管充填后根尖微渗漏的影响。方法 选用60颗离体前牙，采用碘仿氧化锌丁香油糊剂及牙胶尖作侧压充填，实验组在已充填的根管内旋入螺纹钉，对照组不旋入螺纹钉，对两组做根尖部染液渗漏实验。结果 实验组根尖微渗漏较对照组小，两者存在显著性差异。结论 常规根管充填后，采用螺纹钉挤压加固根管充填物，能有效地减少根充术后根尖微渗漏，提高根充密合度。     

GuttaFlow根管充填系统根尖封闭的微渗漏研究

目的评价GuttaFlow常温流动牙胶根管充填系统的根尖封闭性能。方法实验牙沿釉牙骨质界截冠,逐步后退法根管预备,2.5%次氯酸钠冲洗,分别以GuttaFlow常温流动牙胶和SystemB联合ObturaⅡ热牙胶充填系统充填根管。采用改良葡萄糖定量检测微渗漏模型测定第1、2、4、7、10、15、20、30d从冠方向根方渗漏的葡萄糖量。结果GuttaFlow常温流动牙胶和SystemB联合ObturaⅡ热牙胶充填系统的根尖封闭性能均较好,第7d起,GuttaFlow常温流动牙胶的封闭能力显著优于SystemB联合ObturaⅡ热牙胶充填系统(P<0.05)。结论GuttaFlow常温流动牙胶根管充填系统观察期内具有较好的根尖封闭能力。     

4种根管充填技术的根尖微渗漏评价

目的采用葡萄糖定量微渗漏模型,评价不同根管充填技术封闭根尖的能力。方法选取72颗直的单根管牙,沿釉牙骨质界截冠,镍钛旋转器械进行冠向下法根管预备。随机分为4个实验组,每组15例,阳性和阴性对照组各6例。实验A组采用热牙胶垂直加压充填法,B组用固体核心载体充填法,C组用常温流动牙胶充填法,D组用冷牙胶侧压充填法进行根管充填。对照组只用牙胶尖充填,不用封闭剂。实验组和阳性对照组除根尖孔外均涂布2层指甲油,阴性对照组所有牙面均涂布2层指甲油。将牙齿连接于葡萄糖定量检测微渗漏模型,检测1、2、7、14、21、30d从冠方向根方渗漏的葡萄糖含量。通过渗漏葡萄糖的浓度（体积）推算微渗漏的大小。结果阴性对照组l～30d的渗漏值为0,阳性对照组则于ld即检测到较高浓度的葡萄糖。实验A、B、C组最大渗漏量均小于0.18μl/24h即无微渗漏发生,经秩和检验A、B、C3组间无显著差异（P〉0.05）。D组2d开始出现微渗漏,微渗漏量明显多于其它3组（P〈0.05）。结论 GuttaFlow常温流动牙胶法、热牙胶垂直加压充填法和固体核心载体充填法在观察期内,具有较好的根尖封闭能力。     

根管糊剂在ObturaⅡ充填技术中对根尖微渗漏的影响

目的:探讨在Obtura Ⅱ注射式热熔牙胶充填中,不同根管糊剂对根尖微渗漏的影响。方法:40颗单根管牙随机分为4组,采用Obtura Ⅱ注射式热熔牙胶进行根管充填,A、B、C组分别以ZOE、Vitapex、AHplus作为根管糊剂,D组未用糊剂。充填后行墨汁渗透实验,制作透明标本,使用体视显微镜和显微照相系统观测染料渗透的长度。结果:染料自根尖孔渗入根管的长度,D组最长,为4.56±2.72mm,与A、B、C组间差异均有显著性(P<0.05)。在使用糊剂的实验组中,染色线的长度由小到大依次是AHplus1.70±0.82mm、Vitapex1.87±0.56mm和ZOE2.02±0.40mm,但3组之间没有统计学差异(P>0.05)。结论:根管糊剂的使用能显著降低Obtura Ⅱ根管充填后根尖的微渗漏。     

根尖倒充填材料的研究进展

根尖倒充填术的目的是严密封闭根尖孔与根尖周组织的交通，预防根尖微渗漏，常用于非手术治疗失败，不能用常规方法进行根管治疔术且要尽量保留患牙的病例。由于大量材料已应用于根尖倒充填，本文对各种以往在临床和动物实验中常用的根尖倒充填材料作一简要综述。     

Apical leakage following root canal dressing with calcium hydroxide

Abstract The purpose of this study was to analyse the apical leakage in teeth filled by the lateral condensation technique following medication with calcium hydroxide. One hundred and twenty extracted human teeth were biomechanically prepared by using exclusively reaming motion with files up to #40. Half of the teeth received a calcium hydroxide dressing for 3 days. The medication was removed by irrigation and reaming motion with files #40 up to #70. The teeth were divided in 6 experimental groups, according to the dimension of the utilized instrument. The root canals were filled and posteriorly the teeth were placed into a 2% methylene blue dye solution inside a flask, which was attached to a vacuum pump. Leakage was measured linearly, and the results showed significantly (p<0.01) less leakage in the experimental groups that received calcium hydroxide dressings than in the control groups. The results persisted even after the removal of 300 of dentin from the root canal dentinal walls.     

Apical microleakage after lateral condensation, hybrid gutta-percha condensation and Soft-Core obturation: an in vitro evaluation

Abstract— The purpose of the present study was to evaluate the apical seal of root canals filled with a cold lateral condensation, a hybrid gutta-percha condensation technique and with Soft-Core obturators. Three groups of 35 maxillary anterior teeth and four control anterior teeth were treated with a crown-down/step-back technique. All roots were submerged in India ink for 1 week. The roots were cleared and the degree of linear dye penetration was measured. The mean apical leakage for the Soft-Core technique was at least twice as extensive as for the two other gutta-percha obturation techniques. No statistically significant differences were found between the two other condensation techniques.     

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提要：根管治疗术后根尖发生微渗漏是导致根管治疗失败常见的原因之一。根管治疗术后根尖微渗漏的影响因素有很多, 包括根管预备及充填方法、玷污层的处理、根充材料等。本文对此做一综述。     

Leakage of five root canal sealers

AIM: The aim of this study was to examine the apical sealing ability of five root canal sealers using a fluid transport model. METHODOLOGY: A comparison of root canal scalers AH26, AH Plus, Diaket, Apexit, and Ketac-Endo were tested on 60 single-rooted teeth. The coronal part of each tooth was removed at the amelo-cemento junction, and also 3 mm of the root tip. Root canals were instrumented using the 'step-back' technique with Gates Glidden drills and irrigated with 2.5% NaOCl. The specimens were divided into five groups of 10 samples each and filled with test materials and gutta-percha points by the cold lateral condensation technique. Ten teeth were used as a control group, out of which five served as negative and five as positive controls. The leakage was measured by the movement of an air bubble in a capillary glass tube connected to the experimental root section. RESULTS: The differences in leakage amongst Ketac-Endo (0.318 microL: SD 0.084), AH26 (0.319 microL; SD 0.075), AH Plus (0.330L; SD 0.085) Apexit (0.360 microL; SD 0.127) and Diaket (0.387 microL; SD 0.140) were not statistically significant (P > 0.05). CONCLUSIONS: Under the conditions of this study, all five sealers produced a satisfactory seal.     

Comparison of apical leakage shown by four different dyes with two evaluating methods

A study was conducted in vitro to assess and compare the extent of apical leakage of four dyes by two commonly-used evaluation methods. For the study, 120 single-rooted extracted teeth were prepared by the step-back technique and obturated by lateral condensation with gutta-percha and Roth 801 sealer. After randomly allocating the roots into six groups, they were immediately immersed in dye for 72 h, using vacuum for 30 min at 40°C. Teeth were immersed in Eosin, Methylene Blue, Black India Ink and Procion Brilliant Blue and cross-sectioned in 0.7 mm thick slices. Those immersed in Black India Ink and Procion Brilliant Blue were also evaluated by the clearing process. Dye penetration was assessed using a stereomicroscope. A statistically significant greater dye penetration was measured in the cross-sectioned group compared to the clearing group using the same dyes (Black India Ink, P = 0.020, Procion Brilliant Blue, P = 0.040). In the cross-section groups, no statistical significant difference was observed in the amount of leakage comparing the four dyes. No statistically significant difference was found in the leakage pattern of Procion Brilliant Blue and Black India Ink using the clearing technique ( P = 0.797). The evaluating method (cross-sections versus clearing) rather than the dye properties was the main difference between results. More research is needed to standardize dye leakage studies.     

Recurrent Apical Periodontitis and Late Endodontic Treatment Failure Related to Coronal Leakage: A Case Report

Introduction

This article describes a case of late failure after endodontic retreatment as characterized by recurrent post-treatment apical periodontitis.

Methods

At the time of the initial treatment, the patient presented with acute apical abscess associated with a tooth with pulp necrosis caused by trauma. Four years later, the tooth was retreated because of persistent disease. The follow-up examination 28 months after retreatment showed complete healing.

Results

The patient returned 11 years and 7 months later for bleaching of the discolored tooth, and although the periodontal tissues were clinically and radiographically normal, a fracture line was observed on the mesial aspect of the pulp chamber. Extraction was indicated, but the patient only returned 5 years and 9 months later. Then a radiograph showed recurrent post-treatment apical periodontitis. The tooth was extracted, and histopathologic and histobacteriologic analyses revealed bacterial colonies along the fracture line and colonizing ramifications and accessory canals at the apical root canal system.

Conclusions

Coronal leakage can be regarded as the most reasonable explanation for resurgence of the disease. However, a predisposing overlapping condition in the form of root fracture conceivably favored the penetration of bacteria from saliva and plaque biofilm along the filled root canal.     

Evaluation of apical sealing of three endodontic sealers

AIM: The apical sealing ability of three different endodontic sealers was evaluated in extracted teeth using dye penetration. METHODOLOGY: The root canals of 99 extracted human maxillary central incisors were prepared sequentially 2 mm beyond the apical foramen with a size 55 Nitiflex file. The teeth were divided into three experimental groups and obturated by lateral condensation of cold gutta-percha and one of the following sealers: group 1, zinc oxide and eugenol sealer (Fill Canal); group 2, glass ionomer sealer (Ketac-Endo) and group 3, epoxy resin sealer (AH Plus). The teeth were covered with nail varnish to within 1 mm of the apical foramen and immersed in 2% methylene blue in a reduced pressure environment for 24 h. After this period, the teeth were washed and cut longitudinally for apical leakage analysis. The values were obtained from the maximum depth of leakage as well as the average between the maximum and minimum values observed for each group. RESULTS: Statistical evaluation of the results showed no significant difference in the leakage between Fill Canal and Ketac-Endo (P > 0.05). Leakage with AH Plus was significantly less (P < 0.01) than with the other sealers. CONCLUSIONS: All three sealers allowed some leakage to occur. Leakage with AH Plus was significantly different than with Fill Canal or Ketac-Endo.     

慢性根尖周炎一次性根管治疗的临床疗效观察

目的：评价慢性根尖周炎一次性根管治疗的临床效果和可靠性。方法：选择患有慢性根尖周炎的直根管患牙200例,采用改良双敞技术和平衡力法预备根管,0．5％次氯酸钠及17％EDTA冲洗,随机均分为两组：一次性根管治疗组在上述操作完成后立即行牙胶尖加树脂类封闭剂AHplus侧方加压术充填根管;多次性根管治疗组根管内封入氢氧化钙糊剂复诊,待无症状后再行根充。治疗结束后1d、7d、30d随访记录患者的疼痛反应。1年后进行临床及X线复查,计算每组根管治疗的成功及失败率,并进行统计学检验。结果：有94例患者回访,一次性根管治疗组43例,多次根管治疗51例。根管治疗术后1d疼痛发生率一次性治疗组高于多次性组,且有统计学差异,7d、30d的疼痛发生率两组间无明显差异。1年后复查两组的成功率无统计学差异。一次性根管治疗组的前牙与后牙治疗成功率间无统计学差异。结论：慢性根尖周炎一次性根管治疗术后疼痛发生率较多次法高,但远期疗效等同于多次法者。     

Retrograde approaches in endodontic therapy

Abstract The routine use of retrograde fillings during apical surgery, as well as the material of choice for that purpose, have been debated. A retrograde filling is placed so as to seal an infected root canal causing periapical pathosis. Therefore, retrograde root canal fillings should be performed routinely during apical surgery regardless of the apparent technical quality of the root canal obturation, unless orthograde endodontic treatment is performed in conjunction with surgery. When orthograde treatment is not performed in conjunction with surgery. When orthograde treatment is not performed, retrograde root canal filling enhances the prognosis of apical surgery. An array of potential retrograde filling materials have been extensively investigated in vitro and in vivo. Once that the biocompatibility of the materials is confirmed a clinical comparison, rather than in vitro sealability studies, is the most valid evaluation method. Some of the difficulties encountered in long term clinical studies in patients may be avoided in animal studies. The review of the relevant literature of the past decade suggests that amalgam used in conjunction with cavity varnish is the retrograde filling material of choice. It must be stressed, however, that retrograde filling is not comparable to debridement and obturation of the entire root canal. Therefore, when the only way to approach the root canal is from the apical direction, rather than placing an apical retrograde filling, a retrograde endodontic treatment of the entire canal should be preferred, if it is feasible.     

The apical seal of root canal sealing cements using a radionuclide detection technique

The aim of this study was to evaluate the apical seal obtained with various root canal sealing cements using a new method based on the use of a radionuclide and an external detection technique. A total of 150 maxillary incisors and canines, which had been kept in saline solution, were used. The root canals were instrumented with a stepback technique and circumferential filing. Six experimental groups and two control groups were randomly formed. Each experimental group was obturated by a lateral condensation technique with gutta-percha points and a different sealing cement (two based on zinc oxide-eugenol cement, two based on resins and two on calcium hydroxide); the positive control used gutta-percha without sealing cement, while in the negative control the apex was covered with nail varnish, leaving the root canal empty. The apical leakage was measured using an external detection technique after submerging the root apices in a solution containing the radioisotope metastable 99Tc. No leakage was observed in the negative control group. There was a large difference between the leakage observed in the positive control group and the experimental groups. The best seal was obtained using Sealapex cement, which differed significantly from AH26, Tubli-Seal and Diaket; there was no significant difference between the latter. The poorest results were obtained with Endomethasone and CRCS; there was a significant difference between these and the previous three sealing cements.