3种根充糊剂根尖封闭性能的实验研究

目的评价3种根充糊剂的根尖封闭能力。方法30颗离体单根管前牙随机分为国产根充糊剂、Vitapex糊剂和AHPlus糊剂3组,每组10颗,分别用加牙胶尖以冷侧压法充填根管,用染料渗透法和透明标本法在立体显微镜下测量根尖微渗漏。结果3组根尖微渗漏的均值分别为:国产根充糊剂组(2.555±1.129)mm,Vitapex糊剂组(1.212±0.625)mm,AH Plus糊剂组(0.919±0.427)mm,3组间差异有显著性(P<0.01),Vitapex组和AH Plus组的微渗漏无明显差异(P>0.05)。结论Vi-tapex糊剂和AH Plus糊剂的根尖封闭性能均优于国产根充糊剂。     

MTA根尖倒封闭边缘微渗漏的比较研究

目的：比较MTA与银汞合金,Super—EBA根尖倒封闭的性能。方法：用染料渗透法分析离体牙根尖倒封闭术后不同时间的边缘微渗漏情况。结果：染料渗透30d时MTA组边缘微渗漏情况明显优于银汞合金组（P〈0．001）与Super—EBA组相当。60d时,MTA组明显优于Super—EBA组（P〈0．05）和银汞合金组（P〈0．001）。结论：MTA比银汞合金、Super—EBA具有更好的根尖倒封闭性能。     

根管充填材料根尖微渗漏的评估方法研究进展

该文介绍了根尖微渗漏的几种评估方法,包括:染色法、电化学法、放射性同位素渗透法、液体滤过(传输)法和细菌或内毒素渗透法、CT扫描和计算法等。这些方法没有统一的标准,在比较使用这些方法而获得的结果时就较困难。?     

ProTaper简化预备法的根尖微渗漏实验研究

目的观察ProTaper简化预备法的根尖微渗漏,评价其根尖的封闭性能。方法 60颗离体成人患牙,分成2组。实验组30颗牙标本采用ProTaper机动系统简化预备和0.06锥度牙胶尖垂直加压充填根管,对照组30颗牙标本采用逐步后退法0.02锥度不锈钢锉预备和0.02锥度牙胶尖冷侧方加压充填根管,经透明标本染料渗透技术后,测量根尖部染料渗透的距离。结果实验组根尖染料的渗透距离均值0.60 mm,标准差0.29 mm,对照组根尖染料的渗透距离均值1.18 mm,标准差0.83 mm,2组根尖染料的渗透距离差异有统计学意义(P<0.05)。结论 ProTaper简化法预备根管配合相应锥度牙胶尖充填其根尖的封闭性能良好。     

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。     

根尖倒充填术后根尖微渗漏的影响因素

根尖倒充填术后根尖发生微渗漏是导致根尖手术失败常见的原因之一。根尖倒充填术后根尖微渗漏的影响因素有很多,包括根尖切除方法及根尖窝洞预备,对根尖牙本质表面的处理,不同的根尖倒充填材料,以及根管是否充填和pH值等。本文对此作一综述。     

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。     

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。     

四种根尖倒封闭材料边缘微渗漏的定量比较研究

目的　比较研究四种牙体修复材料的根尖倒封闭性能。方法　用标准纸尖法和染料渗透法相结合 ,定量分析离体牙根尖倒封闭术后不同时间的边缘微渗漏情况。结果　染料浸透 7d、14d、2 8d时 ,各试验组间边缘微渗漏差异有极显著性 (P <0 .0 0 0 1) ,玻璃离子组边缘微渗漏情况明显优于合金组 (P <0 .0 5 ) ;2 8d时 ,各试验组根管内纸尖吸液体积均值的大小顺序为 :银汞合金组 >镓合金组 >自凝型GIC组 >光固化型GIC组 (P <0 .0 5 )。结论　光固化型玻璃离子粘固剂比其它三种材料具有更好的根尖倒封闭性能     

Three-dimensional reconstruction: a new method for the evaluation of apical microleakage

The purpose of this study was the evaluation of a new method for studying apical microleakage by using a three-dimensional (3-D) reconstruction method. Fourteen human single-rooted mandibular teeth were used for this work. The canals were prepared with hand instruments by using the step-back technique. To supply a focus to the study of the method, the teeth were divided into two groups that were obturated using two different sealers. India ink was used for passive stain. Serial cross-sections 0.75 mm thick were taken from each specimen by using a special microtome. Each section was photographed under a stereoscopic microscope. Each photograph was digitized and processed to obtain a 3-D reconstruction of the external surface of the teeth, their corresponding prepared root canals, and their apical microleakage. Sample size and experimental methods were not designed to make valid groups; however, apical microleakage was observed in both groups ranging between 2.25 to 8.25 mm height. The 3-D reconstruction method has proved to be a useful tool in the study of apical microleakage.     

In vitro evaluation of two microleakage detection tests.

Two microleakage detection tests were evaluated to compare their capabilities for revealing the extent of leakage at the interface between amalgam restorations and tooth structure. Class V cavities were prepared in the buccal surfaces of extracted human canine and premolar teeth and were treated in one of the following ways: no liner or varnish, a copal varnish, or an adhesive resin liner. The cavities were restored with a high-copper single composition spherical amalgam alloy and the specimens thermally cycled. Following storage for 6 months, the teeth were exposed to separate solutions of 45Ca and an ultraviolet fluorescing dye. The teeth were hemisected longitudinally and leakage was evaluated by determining the degree of penetration of the two tracers at the occlusal and gingival margins. Statistical analysis revealed a significant difference between the two leakage techniques (P less than 0.05). The radioisotope test generally indicated a greater degree of leakage than did the ultraviolet dye test.     

玷污层对根尖微渗漏的影响

目的:利用扫描电镜和葡萄糖定量法评价玷污层对离体牙根管充填后根尖微渗漏的影响.方法:选取51颗单直根管离体牙,随机分为5组进行根管预备,并按分组进行根管冲洗.A组(11颗)--17%乙二胺四乙酸和1%次氯酸钠,B组(11颗)--1%盐酸四环素和1%次氯酸钠,C组(11颗)--10%枸橼酸和1%次氯酸钠,D组(9颗)--1%次氯酸钠.E组(9颗)--生理盐水.每组各选取1个样本进行扫描电镜观察,其余样本进行根管侧压充填.于第1、2、4、7、10、15、20、30天用葡萄糖氧化酶法测定从冠方向根方渗漏的葡萄糖量.实验数据采用SPSS16.0软件包进行重复测量数据的方差分析和SNK-q检验.结果:A、B、C组根管无玷污层结构,微渗漏量较D、E组小(P<0.05);D、E组根管玷污层多,微渗漏量大,E组微渗漏量大于D组(P<0.05).结论:去除玷污层可有效减少微渗漏的发生.     

2种充填系统根尖封闭能力的比较

目的:评价并比较2种充填系统Resilon/Epiphany Self-Etch和牙胶/AH plus的根尖封闭能力。方法 :选取34颗新鲜拔除的单直根管下颌前磨牙。6颗作为阴性和阳性对照组,28颗随机分为2组(每组14颗),预备至同一标准。分别采用2种充填系统Resilon/Epiphany Self-Etch和牙胶/AH plus充填根管,通过印度墨汁渗透试验比较各组的根尖微渗漏。采用SPSS13.0软件包对数据进行统计学分析。结果:2种充填系统的根尖微渗漏有显著性差异,Resilon/Epiphany SE组的渗漏较低(P<0.05)。Resilon/Epiphany SE中封闭剂Epiphany SE通过形成树脂突与牙本质及核心充填材料Resilon紧密黏结,形成一体化结构(mono-block)。结论:Resilon/Epiphany SE充填系统的根尖封闭性能优于传统牙胶充填材料,且封闭剂Epiphany SE与核心充填材料Resilon及根管内结构产生化学性黏结,形成一体化结构。     

Root-end filling materials: apical microleakage and marginal adaptation

The purpose of this study was to evaluate the root-end sealing ability through dye leakage evaluation and the marginal adaptation through scanning electron microscopy (SEM) of some root-end filling materials. Thirty human uniradicular teeth were used. Teeth were divided into three groups: (1) retrofilled with MTA-Angelus, (2) with SuperEBA, and (3) with Vitremer. The root surfaces were isolated with nail polish and teeth were immersed in silver nitrate. Roots were sectioned transversally at each millimeter, in three sections and evaluated at a stereomicroscope to observe dye penetration. Using SEM the distance between the tested root-end filling materials and the surrounding dentin was measured at four points. The statistical analysis showed significant differences among the three materials in relation to the sealing ability (p < 0.05). Concerning marginal adaptation, MTA-Angelus presented the best results (p < 0.01). Absence of correlation between the two methodologies was clearly observed.     

Nd:YAG laser irradiation effect on apical intracanal dentin - a microleakage and SEM evaluation

The purpose of this in vitro study was to evaluate the effect of neodymium:yttrium-aluminum-garnet (Nd:YAG) laser irradiation on intracanal dentin surface by SEM analysis and its interference in the apical seal of filled canals. After endodontic treatment procedures, 34 maxillary human incisors were randomly assigned to 2 groups. In the negative control group (n=17), no additional treatment was performed and teeth were filled with vertically condensed gutta-percha; in the laser-treated group (n=17), the root canals were irradiated with Nd:YAG laser (1.5 W, 100 mJ, 15 Hz) before filling as described for the control group. Two specimens of each group were prepared for SEM analysis to evaluate the presence and extent of morphological changes and removal of debris; the other specimens were immersed in 0.5% methylene blue dye (pH 7.2) for 24 h for evaluation of the linear dye leakage at the apical third. SEM analysis of the laser-treated group showed dentin fusion and resolidification without smear layer or debris. The Student's t-test showed that the laser-treated group had significantly less leakage in apical third than the control group. Within the limitations of this study, it may be concluded that the morphological changes on the apical intraradicular dentin surface caused by Nd:YAG laser resulted in less linear dye apical leakage.     

Comparison of two methods of measuring dye penetration in restoration microleakage studies

This study compared the slice method of measuring microleakage to the whole-wall method. Forty-eight Class V direct metal restorations were placed in the buccal and lingual surfaces of 24 human molars. Following thermocycling and storage in 2% methylene blue stain for 12 hours, the teeth were sectioned and the restorations removed to expose the intact occlusal and gingival cavity walls. Maximum dye penetration axially was determined along either one or two imaginary slices or over the whole wall. Data were statistically evaluated by ANOVA and Tukey's test. Non-uniform staining occurred with 38 of the 96 walls available for evaluation. The average maximum dye penetration depth of the 38 walls was 0.61 mm and 0.70 mm for the slice method using one slice or two, respectively, and 1.29 mm for the whole-wall method. About half of these walls had leakage depths that were more than twice as great as when measured by the slice methods. All 12 of the 38 walls with no leakage when measured by the slice method, showed leakage at least somewhere along the margin when measured by the whole-wall method. This study shows that the whole-wall method detects significantly more leakage than does the slice method (p < 0.0001) and that using two rather than one slice does not improve the detection of leakage (p < 0.1534). Slicing the tooth restoration interface into only two or three sections may seriously underestimate the degree of leakage.     

Effect of removal of the smear layer on apical microleakage

It has been shown previously that the smear layer created during instrumentation of the root canal promotes apical microleakage. The purpose of the present study was to investigate the effect of removal of the smear layer on apical microleakage, using the fluid filtration method. Thirty-six single-rooted human premolar teeth were used. Six of the teeth were selected randomly as controls, and the remaining 30 teeth were randomly divided into two groups of 15 teeth each. For the first group (group 1) teeth were irrigated with NaOCl only (smear layer not removed). In the second group (group 2) the teeth were irrigated with 15% EDTA, followed by NaOCl to remove the smear layer. Both groups were filled with thermoplasticized gutta-percha (Obtura II) using glass-ionomer cement as sealer. All teeth were stored at 37 degrees C and 100% humidity for 2 days. Apical microleakage of the filled root canal was measured by the fluid filtration technique. Hydraulic conductance was measured by the movement of an air bubble in a capillary tube after a pressure of 200 mm Hg was applied to the system. The mean microleakage rate of group 1 and group 2 were 13.0 (SD +/- 5.1) and 16.9 (SD +/- 15.3) nl/s, respectively. Removal of the smear layer caused significantly more apical microleakage (p < 0.05, Student's t test) than when the smear layer was left intact.     

Comparison of generated forces and apical microleakage using nickel-titanium and stainless steel finger spreaders in curved canals

The purpose of this study was to compare (a) forces generated during lateral compaction and (b) apical microleakage for nickel-titanium (NiTi) and stainless steel (SS) finger spreaders. Twenty-eight extracted human teeth were instrumented using a standardized rotary instrumentation technique. NiTi and SS #30 spreaders were used to obturate molar roots while the forces generated during obturation were measured on a Universal testing machine. Apical microleakage was determined using a fluid filtration method. There was no significant difference in microleakage between spreaders. NiTi spreaders produced significantly less force than SS spreaders in all specimens (p < 0.001).