Effect of obturation technique on sealer cement thickness and dentinal tubule penetration

AIM: To compare the average sealer cement film thickness and the extent and pattern of sealer penetration into dentinal tubules in association with four obturation techniques in curved root canals. METHODOLOGY: Mesial canals of 44 extracted mandibular molars were randomly divided among the SimpliFill, continuous wave, Thermafil and 0.04 matched taper (master cones) lateral compaction obturation groups (22 canals per group). AH26 sealer cement was coloured blue-black using Sudan Black B dye. Roots were sectioned 1, 3 and 5 mm from the working length. Specimens were photographed under 25x magnification, mounted as 35 mm slides and projected. Average sealer cement thickness (measured at 10 points around the canal wall), depth of dentinal tubule penetration and frequency of voids were determined at the 1, 3 and 5 mm levels. Data were analysed statistically for effect of obturation technique and level of section on sealer thickness and on the depth and distribution of tubule penetration. RESULTS: Thermafil demonstrated superior GP adaptation at all levels with a mean overall sealer cement thickness of 2.2 microm, followed by lateral compaction (11.1 microm), continuous wave (12.2 microm) and SimpliFill (47.6 microm). SimpliFill also demonstrated the highest frequency of voids (P < 0.05). Sealer cement penetrated dentinal tubules as far as the outer one-third of dentine, with greater penetration observed buccally or lingually (P < 0.001). Penetration was not significantly affected by obturation technique, but on average was deeper and more frequent at the 3 and 5 mm levels than at the 1 mm level (P < 0.001). CONCLUSIONS: Sealer thickness was strongly dependent on obturation technique. Assuming that minimal sealer thickness and fewer voids are good measures of long-term sealing ability, Thermafil resulted in the best outcome. Consistent, extensive sealer penetration into dentinal tubules was seen and was unrelated to the obturation technique.     

自固化磷酸钙根管封闭剂的临床疗效初步评价

目的:观察自固化磷酸钙根管封闭剂作为根管充填材料的临床疗效。方法:选择136例慢性根尖周炎患者,常规根管预备后,随机选择72例为实验组,采用牙胶尖和自固化磷酸钙根管封闭剂充填根管;对照组64例,以牙胶尖和碘仿糊剂充填根管。术后1周、3个月、6个月、1a复查,观察术后反应情况,评价临床疗效,对数据进行χ2检验和Wilcoxon等级秩和检验,应用SAS6.2统计软件包。结果:实验组的术后反应较小,3个月的临床成功率高于对照组;而随着观察时间的延长,两者间差异无显著性。结论:自固化磷酸钙根管封闭剂可作为一种根管充填材料使用,远期疗效有待进一步研究。     

老年人部分闭锁根管的预备

目的:总结对老年人部分闭锁的根管进行根管预备的特点.方法:对50例根管闭锁需进行根管治疗的牙齿,经常规手持器械预备辅助以化学预备——乙二胺四乙酸(EDTA)液,双氧水及氯亚明反复冲洗根管,同时相应增加复诊次数,对根管进行多次预备.结果:50例患牙最终获得满意的根管预备.结论:对于老年人部分闭锁的根管,通过手持器械加化学预备多次根管扩大,可以获得满意的根管预备.     

Analysis of the gutta-percha filled area in C-shaped mandibular molars obturated with a modified MicroSeal technique

Aim  To analyse the gutta-percha filled area of C-shaped molar teeth root filled with the modified MicroSeal technique with reference to the radiographic features and the C-shaped canal configuration.
Methodology  Twenty-three mandibular second molar teeth with C-shaped roots were classified according to their radiographic features as: type I – merging, type II – symmetrical and type III – asymmetrical. The canals were root filled using a modified technique of the MicroSeal system. Horizontal sections at intervals of 600 μm were made 1 mm from the apex to the subpulpal floor level. The percentage of gutta-percha area from the apical, middle and coronal levels of the radiographic types was analysed using the Kruskal–Wallis test. Complementary analysis of the C-shaped canal configurations (C1, C2 and C3) determined from cross-sections from the apical third was performed in a similar way.
Results  No significant differences were found between the radiographic types in terms of the percentage of gutta-percha area at any level ( P  > 0.05): apical third, type I: 77.04%, II: 70.48% and III: 77.13%, middle third, type I: 95.72%, II: 93.17%, III: 91.13% and coronal level, type I: 98.30%, II: 98.25%, III: 97.14%. Overall, the percentage of the filling material was lower in the apical third ( P  < 0.05). No significant differences were found between the C-shaped canal configurations apically; C1: 72.64%, C2: 79.62%, C3: 73.51% ( P  > 0.05).
Conclusions  The percentage of area filled with gutta-percha was similar in the three radiographic types and canal configuration categories of C-shaped molars. These results show the difficulty of achieving predictable filling of the root canal system when this anatomical variation exists. In general, the apical third was less completely filled.     

玷污层及封闭剂对Ultrafil-3D系统根尖封闭的影响

目的:观察有无玷污层及不同类型的封闭剂对Ultrafil-3D系统根管充填封闭性的影响。方法:64颗人离体单、直根管前牙预备后,将其中的60颗分为有玷污层与无玷污层组,各组分别采用3种封闭剂(AH-plus、Roekoseal、CRCS)并以Ultrafil-3D牙胶(Firmset)充填根管,其余4颗作为对照。所有标本在2%亚甲蓝中浸染5d,将牙体近远中向纵劈后,测量染料的线性染色长度。采用SAS6.04软件包进行方差分析及t检验。结果:(1)无论玷污层去除与否,CRCS组的微漏均显著大于AH-plus及Roekoseal组(P<0.05);(2)去除玷污层前后,使用3种封闭剂的染料微漏均无显著差异(P>0.05)。结论:AH-plus及Roekoseal与Ultrafil-3D牙胶联合使用,能增加根管充填的密合性,去除玷污层不能明显减少微漏的发生。     

C形根管的形态与识别

根管治疗中根管的机械化学预备是感染控制的关键步骤,但C形根管的形态给根管的清理、成形带来巨大的挑战.在治疗前正确识别、评估根管形态变得尤为重要.随着检查方法的进步及设备、耗材的更新,C形根管的诊断率及治疗成功率均得到了显著提高.因此,了解C形根管的形态及临床意义,掌握C形根管的临床检查和识别方法,对于提高根管治疗成功率...     

Determination of pH and calcium ion release provided by pure and calcium hydroxide-containing AHPlus

AIM: To compare in vitro the pH and calcium ion release provided by pure and calcium hydroxide-containing AHPlus. METHOD: Pure and modified AHPlus, the latter containing 5 and 10% (w/w) calcium hydroxide added during spatulation, were used. The material was spatulated and stored in 10 tubes that were 1 cm long and 1.5 mm in diameter, and then immersed in 20 mL deionized water before the materials had set. Ten tubes with zinc oxide and eugenol were used as controls. Four millilitres of water was removed from the flasks after 24 and 48 h, and after 7, 14 and 30 days, and pH and calcium release were measured with a pH meter and by atomic absorption spectrophotometry, respectively. The results obtained at each time point were compared statistically. RESULTS: A more alkaline pH for AHPlus supplemented with 5 and 10% calcium hydroxide was recorded when compared to pure AHPlus; there were significant differences at 14 and 30 days (P<0.05). The results of calcium ion release showed no significant difference between pure AHPlus and zinc oxide plus eugenol (P>0.05). The comparisons between the AHPlus containing 10% calcium hydroxide with AHPlus containing 5% calcium hydroxide, pure AHPlus, zinc oxide plus eugenol demonstrated significant differences (P<0.05) at all periods. The comparisons between AHPlus containing 5% calcium hydroxide with pure AHPlus and zinc oxide plus eugenol demonstrated significant differences (P<0.05) at all periods of evaluation. CONCLUSIONS: The addition of 5 and 10% calcium hydroxide to AHPlus cement favoured a more alkaline pH and greater calcium ion release.     

Comparison of cold lateral condensation and a warm multiphase gutta-percha technique for obturating curved root canals

AIM: The aim of this project was to evaluate and compare the radiographic quality and sealability of root fillings in extracted human teeth using lateral condensation of gutta-percha or multiphase gutta-percha obturation (Alphaseal). METHODOLOGY: A total of 108 freshly extracted human, mature single-rooted teeth were divided into two identical groups of 54 teeth on the basis of root canal shape. The canals were prepared to a minimum 0.055 taper and enlarged to size 35 at the apex. All root canals were flushed with 17% EDTA solution and 2.5% NaOCl to remove the dentinal smear layer. The canals of one group were obturated using cold lateral condensation of gutta-percha and the canals of the other group were filled using a warm multiphase gutta-percha obturation technique. The extrusion of sealer and/or gutta-percha through the apex of the teeth was recorded using a simple yes/no scheme. The sealability of each technique was assessed by a dye penetration method. The radiographic quality of obturation was determined for each canal using a four-point scale. RESULTS: Root canals filled by multiphase obturation had significantly more extrusion of sealer (P < 0.001) and gutta-percha (P < 0.001) than canals filled by lateral condensation. Canals filled by multiphase gutta-percha obturation had significantly less apical dye leakage than those obturated by lateral condensation (P < 0.05). Lateral condensation achieved significantly better scores for radiographic quality than multiphase obturation from the bucco-lingual view (P < 0.01). CONCLUSIONS: Under laboratory conditions multiphase gutta-percha had better sealability but poorer radiographic quality than lateral condensation.     

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目的评价根管封闭剂iRootSP的根尖封闭效果。方法选择2012年9—12月中国医科大学口腔医学院口腔外科拔除的单根管前牙50颗,随机分为2个实验组（A、B组,每组20颗）和2个对照组（c组为阳性对照组,D组为阴性对照组,每组5颗）。所有牙均常规开髓、拔髓,采用机用ProTaper设备根管至F2。A、B组分别采用根管封闭剂iRootSP加单尖充填技术和根管封闭剂AHPlus加单尖充填技术充填根管,c、D组均不做任何根管充填;4组牙齿均用光固化复合树脂充填髓腔及开髓孔。A、B、c组在除根尖孔2mm外的整个牙根表面均匀涂布指甲油2遍,D组在牙根表面及根尖孔全部涂布指甲油2遍。采用染料渗透法检测根尖微渗漏情况,对各组染料渗透长度进行比较分析。结果A、B组均有不同程度的根尖微渗漏,A组染料渗透长度为（1．62±0．20）mm,B组为（1．80±0．20）mm,两组间差异无统计学意义（P〉0．05）。作为阳性对照的c组,染料渗透长度为（10．75±1．28）mm,几乎渗入牙根全长;作为阴性对照的D组,则无染料渗入牙根。结论根管封闭剂iRootSP的根尖封闭性能与AHPlus相似。由于单尖充填技术操作简便,副损伤小,省时省力,具有良好的临床应用前景。     

Evaluation of calcium hydroxide-containing root canal sealers with an improved rabbit ear chamber

Abstract An improved rabbit ear chamber was used to evaluate calcium hydroxide-containing root canal sealers on their potential in induce dystrophic calcification in connective tissue. Four sealers and two control materials were introduced into the chambers and the effects of these materials on the living vascular tissue were observed continuously under a biomicroscope up to 9 weeks. Conventional histopathological investigation and examinations with a scanning electron microscope and an X-ray microanalyzer were done to supplement the results. Sealapex and Calvital (Ca(OH)₂+ iodoform) revealed almost the same tissue reaction as calcium hydroxide-saline paste; they rapidly made a precipitate-barrier of calcium phosphate in the connective tissue, inducing calcification. However, Dentalis KEZ(ZnO-ca(OH)₂+ eugenol) caused mild disorders of microcirculation without calcification, as well as Canals(ZnO + eugenol). New A (Ca(OH)₂+ fatty acid) had good compatibility with micro-vessels as well as New B(ZnO + fatty acid), however they induced no calcification and disintegrated rapidly in the tissue. These sealers were reclassified according to what they actually bring about in the tissue, not according to what they include.     

Efficacy and retrievability of root canal filling using calcium silicate‐based and epoxy resin‐based root canal sealers with matched obturation techniques

This study aimed to compare the efficiency of root canal filling procedures and the retrievability of the filling material with various sealers. Forty‐three patients assigned to endodontic treatment with (i) continuous wave of condensation technique (CTW) with AH‐plus (ii) single‐cone technique (SCT) with EndoSeal MTA. The spent time, voids entrapping and postoperative symptoms were evaluated. To evaluate the retrievability, mandibular premolar (n = 60) were divided into four groups: AH‐plus/CTW, EndoSeal MTA/SCT, MTA Fillapex/SCT and EndoSequence BC Sealer/SCT. The time required removing the filled materials and remnant score were examined. EndoSeal MTA/SCT showed significantly shorter time of filling procedure. The number of void did not show significant differences between two techniques. No patients showed clinical signs during the follow‐up periods. There were no significant differences between group AH‐plus and EndoSeal MTA for remnant score. A certain calcium silicate‐based sealer with SCT may give similar clinical efficiencies as much as continuous‐wave technique using AH‐plus sealer.     

Tissue response to an experimental calcium hydroxide-based endodontic sealer: a quantitative study in subcutaneous connective tissue of the rat

Abstract Silicone tubes containing a freshly mixed experimental Sealapex, in which titanium dioxide was removed from the original formula, were implanted in the dorsal subcutaneous connective tissue of the rat. Solid silicone rods of the same size as the tubes were also implanted and used as inert controls. The tissue reaction to both these materials was histometrically and quantitatively studied under light microscopy and by elemental electron microprobe analysis. After 7, 30 and 90 d of implantation, different grades of tissue reaction to the tested materials were recorded. A granulomatous tissue containing numerous foreign-body giant cells and macrophages with engulfed particles in their cytoplasms was initially detected in contact with the test material. In addition, many fibroblasts and newly formed vessels were also observed at these areas. The results of this study revealed that these reactions increased progressively at the 30-and 90-d observations. The electron microprobe analysis of the granulomatous tissues showed the presence of heavy components of the experimental material.     

Obturation of root canals with different sealers using non-instrumentation technology

AIM: To evaluate and compare the sealing quality of hand- or vacuum-obturated root canals after hand preparation or hydrodynamic cleansing of root canals, respectively. METHODOLOGY: After assessing root curvature, 96 single-rooted deep-frozen teeth were divided into eight comparable groups. The root canals of four groups were instrumented with the balanced force technique. The remaining uninstrumented teeth were connected to a reduced-pressure device (NIT) and the root-canal system perfused with 2.5% NaOCl under alternating pressure fields. This dissolved the pulpal tissues and removed debris from the root-canal system. The canals of the hand-instrumented groups were obturated using the cold lateral condensation method with guttapercha and one of four different sealers (AH26, AH Plus, Apexit and Pulp Canal Sealer EWT). The teeth treated with the alternating pressure device (NIT) were obturated by a vacuum obturation method (NIT) with the same four sealers. The quality of the coronal seal was assessed using a dye penetration method. In order to minimize errors the roots were perfused with water before exposure to the dye, under vacuum. The teeth were then rendered transparent and the depth of penetration of the dye between the wall of the canal and the obturating material was measured with a stereomicroscope. RESULTS: The canals cleaned and filled by NIT showed statistically significantly less dye penetration than those obturated by lateral condensation (P < 0.05). Within the NIT group, Pulp Canal Sealer EWT exhibited significantly more dye penetration than Apexit. Amongst the control lateral condensation groups no significant differences were found between the various sealers. CONCLUSIONS: The present investigation demonstrated the validity of the NIT obturation method in combination with commonly used root-canal sealers.     

Bacterial leakage in obturated root canals following the use of different intracanal medicaments

Abstract – The aim of this study was to examine whether intracanal medication prior to root canal obturation has an inhibitory effect on corono-apical penetration of bacteria. 93 single rooted teeth were instrumented and sterilized with ethylene oxide. They were assigned to three control groups and four test groups with n =20 each. For one week, they were dressed with different medicaments: The first group with a 5% chlorhexidine gel, the second with Ledermix, the third with a fresh mix of calcium hydroxide and water and the fourth without any medication. After obturation (lateral condensation, AH26) the roots were fixed between a top and a bottom chamber. The top chamber contained 3 mL trypticase soy broth with 10⁸ Staphylococcus epidermidis CFU's/mL, whereas the bottom chamber contained sterile trypticase soy broth. For one year, the mounts were incubated at 37°C. They were checked on a regular basis for turbidity in their bottom chambers indicating bacterial growth. None of the test samples leaked for three months. After one year, the calcium hydroxide group had only 6 leaking samples whereas the chlorhexidine group had 14, the Ledermix group 15, and the unmedicated group had 13 leaking samples. It may be concluded that under the conditions of this study, calcium hydroxide was the medicament of choice to avoid bacterial penetration of the root canal. Ledermix did not perform better than no pre-medication. Chlorhexidine was superior to Ledermix in the second third of the observation period.     

玷污层及不同根管封闭剂对根管充填后根尖微渗漏的影响

目的:评估玷污层、根管封闭剂对根管充填后微渗漏的影响。方法:选择新鲜拔除的根尖发育完成的单根管人前牙,常规预备根管,随机分4组:A(AH-plus),B(Apexit),C(氧化锌丁香油糊剂),D(根管糊剂),各组内再分为1、2组,1组在充填前用170g/LEDTA和52.5g/L次氯酸钠溶液交替冲洗以去除玷污层,2组仅用52.5g/L次氯酸钠溶液冲洗,所有牙采用侧方加压法充填根管后,在冠方插入铜丝使其与牙胶接触,浸入生理盐水溶液中,在每牙与一不锈钢电极间加12V的直流电,观察40d,用单因素方差分析和LSD-t检验比较10、20、30、40d时的数据。结果:AH-plus、Apexit产生的微渗漏低于氧化锌丁香油糊剂、根管充填糊剂,而AH-plus又低于Apexit,去除玷污层使AH-plus产生低的微渗漏值。结论:AH-plus、Apexit的封闭能力优于氧化锌丁香油糊剂、根管充填糊剂,去除玷污层能增加AH-plus的封闭能力。     

A clinical evaluation of one and two-appointment root canal therapy using calcium hydroxide

A clinical study using vital maxillary central incisors was performed to evaluate the incidence of postoperative pain after root canal treatment in one- or two-appointments using a calcium hydroxide-containing root canal sealer. No differences were observed between the two groups.     

不同根管预备方法对直根管即刻桩腔预备根尖封闭性影响的研究

目的观察直根管不同根管预备方法根管充填后即刻桩腔预备对根尖封闭性的影响。方法离体直单根管上前牙84个,其中80个按根管预备方法随机平均分为2组(n=40),A组:不锈钢根管锉常规法;B组:G型钻根管冠部预处理+不锈钢根管锉常规法,其余4个随机平均分配为阴性对照组和阳性对照组。所有根管均用侧方加压法充填,即刻垂直加压器去除部分充填材料,然后P型钻桩腔预备。用染料渗透法评价各组根尖封闭能力。结果B组的根管进行即刻桩腔预备后,其根尖微渗漏较A组轻(P<0.05)。结论大锥度根管预备,根管充填后即刻桩腔预备根尖封闭性较好。