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。     

用罗丹明B染料比较MTA、GIC和银汞合金的根尖封闭性

目的:用罗丹明B染料比较MTA、GC Fuji Ⅱ(GIC)和银汞合金的根尖封闭性.方法:将离体牙分别用以栽上3种材料进行根尖倒充填后,用0.2%罗丹明B溶液染色,再将牙体纵劈,置于解剖显微镜下测量洞壁染料渗透最大深度并拍照.SPSS10.0统计软件进行分析.结果:MTA组的渗漏深度显著小于银汞合金组(P＜0.05),而银汞合金组的渗漏深度显著小于GC Fuji Ⅱ组(P＜0.05).结论:3种材料中,MTA的根尖封闭效果最好,其次为银汞合金,而Fuji Ⅱ的效果最差.     

新型硅酸钙基生物材料用于根尖倒充填的封闭性能和粘接强度的研究

目的:评价和比较硅酸钙基生物材料iRoot BP Plus和MTA作为根尖倒充填材料的封闭性和粘接强度。方法:收集因正畸或牙周病新鲜拔除的单根离体牙93颗,截去牙冠后行常规根管预备、根管充填,切除根尖3mm后行根尖倒预备,随机分为3组:A组(iRoot BP Plus组)、B组(MTA组)、C组(GIC组),分别行根尖倒充填。扫描电镜下观察并比较不同倒充填材料与牙本质之间粘接界面的微观形态;薄片推出实验体视显微镜下观察各组的断裂形式;测量染料渗透深度结合图像软件分析不同的微渗漏结果。结果:扫描电镜显示:iRoot BP Plus与根管壁牙体组织之间的粘接界面结合具有好的边缘适应性。薄片推出实验发现,iRoot BP Plus和MTA两组间的粘接强度无显著性差异,均明显高于GIC组(P<0.05);三组均以混合型为主要断裂方式,GIC组内粘接型断裂形式所占比例相对最高。微渗透结果显示,iRoot BP Plus和MTA的渗透深度相比无统计学差异,均明显低于GIC组(P<0.05)。结论:iRoot BP Plus与MTA作为根尖倒充填材料都具有较好的根尖封闭性能和粘接强度,均优于传统倒充填材料GIC。     

不同材料及根尖术式对根管封闭性的影响

目的:评价MTA、iRoot BP Plus两种根管充填材料在根管正充填与倒充填两种不同根尖术式下的根管封闭效果。方法::收集因牙周、正畸拔除并符合标准的下颌恒前磨牙40颗,根管预备后随机分为4个实验组(n=8)和2个对照组(n=4):A组(MTA正充填组)、B组(iRoot BP Plus正充填组)、C组(MTA倒充填组)、D组(iRoot BP Plus倒充填组)、M组(阳性对照组)、N组(阴性对照组)。使用印度墨汁染色技术,透明牙技术评价两种材料在根管正充填与倒充填两种不同根尖术式下的根管封闭效果。结果:各实验组根方均有不同深度的墨汁渗入,A、B组较C、D组微渗漏值稍大,但各组间差异无统计学意义(P>0.05)。结论:MTA、iRoot BP Plus在根管正充填与倒充填两种不同充填方式下能取得同样的根尖封闭效果。因此,对于部分特殊部位的根尖病变以及止血困难等行根尖倒预备、倒充填较困难的病例可以选择MTA或iRoot BP Plus正充填后再行根尖切除这一手术方式作为有效的替代方式。     

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     

iRoot BP修复磨牙髓室底穿孔的研究

目的 探讨iRoot BP直接修复髓室底穿孔的效果。方法 收集新鲜拔除的人恒磨牙40颗,其中36颗于髓室底中央制备直径2 mm的穿孔洞型,随机分为A、B组,每组18颗,分别用iRoot BP和矿物三氧化聚合体（MTA）修复髓室底穿孔;另外4颗为对照组,只开髓不制备髓室底穿孔。从A、B组中各随机选择3个样本用扫描电子显微镜观察材料和牙本质的结合界面;其余15个样本用葡萄糖氧化酶-蒽酮法检测微渗漏值。结果 A组中,iRoot BP与牙本质结合较为紧密,而B组中MTA和牙本质之间存在不均匀的微小间隙。在观察期内,B组的微渗漏值高于A组,其差异有统计学意义（P<0.05）。结论 iRoot BP修复髓室底穿孔的封闭效果优于MTA。     

不同根尖倒充填材料的微渗漏研究

目的 评价MTA、玻璃离子水门汀、复合树脂3种根尖倒充填材料根尖封闭性能.方法 60颗实验牙沿釉牙骨质界截冠,冷侧压法充填根管后,切除根尖3 mm.实验组超声倒预备3 mm,分别以MTA、玻璃离子水门汀、复合树脂做倒充填,固化后上段取出牙胶.对照组保留根尖3 mm牙胶.连接于改良葡萄糖定量检测微渗漏模型,分别在1、2、4、7、10、15、20、30 d测定从冠方向根方渗漏的葡萄糖的量.结果 MTA、玻璃离子水门汀、复合树脂3种材料葡萄糖渗漏量均小于0.60 μl/24 h,从第4 d起,MTA的渗漏量显著低于玻璃离子水门汀和复合树脂(P＜0.05).结论 MTA、玻璃离子水门汀、复合树脂3种材料短期内的根尖封闭性均较好,MTA优于其它两种材料.     

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。     

Er,Cr:YSGG激光切割对牙根尖封闭效果影响的微渗漏研究

目的 :探讨Er,Cr:YSGG激光进行根尖切除、预备后对倒充填材料密合性的影响 ,为此激光在临床上的应用提供重要的理论及实验依据。方法 :将 32个新拔除的单根离体牙随机分成 4组。去除牙冠 ,常规根管充填。第 1组 ,不做任何处理 ,作为阳性对照组 ;第 2组 ,手机切割组 ,手机进行根尖切除、预备后 ,银汞合金倒充填 ;第 3组 ,激光照射组 ,2WEr,Cr:YSGG激光于无水条件下照射根尖区 6s;第 4组 ,激光切割组 ,4WEr,Cr:YSGG激光于喷水条件下进行根尖切除、预备后 ,银汞合金倒充填。采用微渗漏实验对此激光切割后的牙根尖封闭效果进行评估。结果 :与阳性对照组相比 ,激光照射组的染料微渗漏深度无显著改善 (P >0 .0 5 ) ;与手机切割组相比 ,激光切割组的染料微渗漏深度有所减少 ,但并无显著性差异 (P >0 .0 5 )。结论 :Er,Cr:YSGG激光进行根尖切除、预备与常规手机预备具有同样的根尖封闭效果 ,因此有望在根尖倒充填术中取代手机 ,应用于口腔临床。     

根管冠部预处理和不同锥度牙胶尖对根管充填后根尖部封闭性能的影响

目的:比较根管冠部预处理和不同锥度牙胶尖根管充填后的根尖封闭能力。方法:离体单根管恒牙42个,随机分为4组,用染料渗透法和透明标本法,测量根尖微渗漏距离,评价各组根尖封闭能力。结果:GG钻预处理和0.02锥度牙胶尖组根尖封闭能力最好;不用GG钻预处理和0.04锥度牙胶尖组根尖封闭能力最差。结论:根管预备时进行中上段的预处理,有利于增强根管充填后根尖段的封闭能力;用大锥度牙胶根管充填时应充分敞开根管中上段,否则易影响根尖段的充填效果,造成微渗漏;根管预备时进行冠方预处理,侧方加压法根充时选用合适的小锥度牙胶尖能取得较好的根管充填效果,提高根尖封闭能力。     

Comparative study of sealing ability of two root-end-filling materials with and without the use of dentin-bonding agents

The purpose of this study was to examine microleakage of two root-end-filling materials with and without the use of bonding agents. For microleakage measurement a fluid transport model was used. Sixty single-rooted teeth were used in this study. They were prepared with step-back technique and then an apicoectomy was performed. Then the teeth were divided into four groups. Group A were filled with Fuji II LC glass-ionomer cement, group B were filled with Fuji II LC and a new bonding agent, Fuji Bond, group C were filled with Admira composite resin, and group D were filled with Admira and Admira Bond, a new bonding agent. At 24 h, 1 month, and 2 months after filling the leakage along these filling materials was determined under a low pressure of 0.1 atm. At all experimental times, glass-ionomer groups showed significantly less microleakage than resins groups. Between Admira and Admira Bond groups, significantly less leakage was observed in the root sections with Admira Bond at 24 h.     

The marginal seal of Class II restorations: flowable composite resin compared to injectable glass ionomer

The objective of this study was to investigate the effect of a flowable composite resin (Tetric Flow) versus an injectable glass ionomer (Fuji II LC) on microleakage at the cavosurface margin of the proximal box of Class II restorations in permanent teeth in-vitro. Thirty caries and restoration-free human bicuspids were prepared with mesial and distal slot preparations and were filled either with a bonding agent (Optibond) plus a flowable composite resin (Tetric Flow), Group I; bonding agent (Optibond) plus a flowable glass ionomer (Fuji II LC), Group II; or a flowable glass ionomer (Fuji II LC) with no bonding agent, Group III. All specimens were then immersed in a 2% solution of basic fuschin dye for 24 hours to allow for dye penetration into possible existing gaps. These teeth were then carefully sectioned mesially/distally into two pieces using an Isomet saw. The teeth were then studied under a binocular microscope to measure depths of dye penetrations as an indication of marginal microleakage at the gingival cavosurface margin and scored as follows: 0 = no dye penetration, 1 = dye penetration into enamel only, 2 = dye penetration into enamel and dentin, 3 = dye penetration into the pulp. The specimens were also evaluated using a SEM. The results showed that there were statistically significant differences between Groups I (Tetric Flow) and (Fuji II LC plus bonding agent), II in favor of Group I; between Groups I and (Fuji II LC with no bonding agent), III in favor of Group I; as well as Groups II and III in favor of Group II (Fuji II LC plus bonding agent). Group I (bonding agent plus flowable composite resin) showed significantly less microleakage. Group II (bonding agent plus flowable glass ionomer) demonstrated a bond that existed between the bonding agent and the glass ionomer but microleakage within microgaps of the glass ionomer itself Group III (flowable glass ionomer plus no bonding agent) demonstrated significant microleakage between the glass ionomer and tooth structure, microgaps within the glass ionomer, and lack of retention of the restoration. It appears that the use of a flowable composite resin (Tetric Flow) plus a bonding agent (Optibond) in the proximal box of a Class II restoration in permanent teeth will significantly reduce the microleakage at the cavosurface margin when compared with an injectable glass ionomer (Fuji II LC) with or without a bonding agent (Optibond).     

Microleakage study of flowable composite resin systems

The purpose of this in vitro microleakage study was to evaluate four low-viscosity composite resin systems. Each resin system included the corresponding bonding agent for each respective flowable composite. A hybrid material was used as a control. A total of 75 noncarious, freshly extracted human teeth were prepared with a Class 5 occlusal preparation and a gingival preparation at the cementoenamel junction. The materials were inserted according to the manufacturers' recommendations using the single-component bonding agent for each system. Teeth were thermocycled 800 times between 5 degrees C and 55 degrees C with 30-second dwell times. The teeth were then coated with nail polish 1 mm short of the restoration, placed in a basic fuchsin dye for 24 hours, and sectioned with a diamond wheel. Enamel and dentin/cementum margins were analyzed for microleakage on a scale of 0 (no leakage) to 3 (axial wall). Results were evaluated with the Fisher's exact test. The results of the study indicate that there was no leakage at the enamel margin of any restorations. No statistically significant differences in microleakage were found in dentin/cementum margins among the samples in the experimental group or between the experimental group and control group. The results indicate flowable composites demonstrate resistance to microleakage in both enamel and cementum/dentin margins similar to TPH hybrid composite.     

Effects of Nd: YAG laser irradiation on the adaptation of composite resins to root dentin

One of the most important goals of the restoration of endodontically treated teeth with a composite resin post system is to achieve good adaptation of the composite material to dentin walls to prevent microleakage apically and coronally. In post core systems, to avoid microleakage between the dentin wall and resin material, laser irradiation may seem to be an alternative therapy for increasing adaptation quality. The aim of this study was to investigate the adaptation of a packable composite resin to lased root canal dentin when it was used as post material. Forty-five freshly extracted human teeth were selected and post spaces were prepared. The teeth were divided into three groups. In group 1 the dentin of the post spaces were etched with 35% phosphoric acid, in group 2 the dentin surfaces were irradiated with an Nd: YAG laser, and in group 3 the dentin surfaces were initially treated with the laser and then etched. The teeth of all groups were obturated with a bonding agent and composite. The groups were divided into two subgroups: a group for the scanning electron microscope (SEM) study and a group for the microleakage study. The lased group showed poor adaptation and more microleakage was detected (p<0.05; variance analysis). The laser beam and acid-etching showed no advantage compared to the acid-etching alone (p>0.05). The Nd: YAG laser irradiation adversely affects adhesion to dentin for using composite resin as a post material and does not constitute an alternative to acid-etching.     

Effect of composite resin placement and use of an unfilled resin on the microleakage of two dentin bonding agents

The purpose of this study was to assess, in vitro, the microleakage of Class V restorations using two third generations dentin bonding agents, with a hybrid light polymerized composite resin. One of the bonding agents was of the NPG-PMDM type and the other was a polyhexanide. Restorations were placed in cavities prepared in extracted human premolars using either a bulk or incremental packing technique. The NPG-PMDM-based agent was used with and without an intermediary unfilled resin. The teeth were stored for 1 week at 37 degrees C, thermocycled for 1500 cycles between 55 degrees C, 37 degrees C and 5 degrees C and the restorations examined for leakage using methylene blue dye. The teeth were sectioned through the restorations and the degree of microleakage assessed visually. All groups of restorations showed some degree of leakage at the gingival margin. Statistical analysis showed that there were significant differences in the amounts of leakage (P less than 0.001). There was no difference in leakage between any of the groups that had been restored using the NPG-PMDM system (P greater than 0.05). There was, however, less leakage of the incrementally filled group compared with the bulk-packed group with the polyhexanide agent (P less than 0.05). When the two bonding agents were compared, there was no significant difference in leakage (P greater than 0.05) except for the incrementally-packed polyhexanide and the incrementally-packed NPG-PMDM with unfilled resin (P less than 0.05). Only one specimen in any of the groups leaked at the enamel margin.     

Microleakage in MOD resin composite with three dentin bonding agents

The extent of microleakage under MOD composites was studied when an aluminum oxalate dentin bonding agent (Tenure), a phosphonated resin bonding agent (Bondlite), and a glass-ionomer cement (Ketac Silver) were used. Three groups of 10 extracted molars were prepared with MOD cavities; one box ended on enamel, the other on cementum. In Group 1, Bondlite was applied to dentin and etched enamel before the sample was restored with a light-cured hybrid composite. In Group 2, a 2-mm increment of Ketac Silver was placed in each box before Bondlite and composite. In Group 3, Tenure was applied to dentin before being restored. Teeth were thermal-cycled, stained in silver nitrate, sectioned, and scored for microleakage. Microleakage along the gingival floor was significantly less at enamel margins than at cementum margins in all three groups. All groups showed severe marginal microleakage on cementum.     

In vitro bacterial penetration of endodontically treated teeth coronally sealed with a dentin bonding agent

This study evaluated the effectiveness of a dentin bonding agent as a barrier to prevent coronal microleakage and examined the effect of a eugenol-based sealer on the sealing ability of this resin adhesive. Fifty-one extracted human mandibular molars were incorporated in a model system using an oral streptococci as a microbial marker. Group 1 consisted of 15 teeth that were obturated with only gutta-percha and received a coronal barrier of Clearfil Liner Bond 2V. Group 2 was identical to group 1, but included the use of a eugenol-based sealer in the obturation. Group 3 consisted of 15 teeth that were obturated with gutta-percha and sealer, but did not receive a coronal barrier. Six teeth served as controls. Bacterial penetration was monitored for 90 days. Results were analyzed after 30, 60, and 90 days with Fisher's exact test (p < 0.05). All controls behaved as expected. Neither group 1 nor group 2 exhibited any bacterial leakage. Eleven of the 15 specimens in group 3 leaked between 15 and 76 days. The coronal barriers in group 1 and group 2 were significantly better in preventing coronal microleakage at 60 days (p = 0.002) and 90 days (p = 0.00005). The presence of eugenol in the sealer had no significant effect on the sealing ability of Clearfil Liner Bond 2V (p = 1).     

Effect of various surface treatments on the microleakage and ultrastructure of resin-tooth interface

This study evaluated the effect of collagen removal and sodium ascorbate treatment of acid-etched dentin on the microleakage and ultrastructure of resin-tooth interface under moist and dry conditions using an acetone-based 1 bottle adhesive system. Class V cavities were made on the buccal surfaces of 90 premolars scheduled for orthodontic extraction. The cavities were etched with 37% phosphoric acid (DPI tooth conditioning gel/India) for 15 seconds. The teeth were divided into six groups with 15 teeth each. In Group 1, the etched surface was blot dried with a dry cotton pellet, leaving it visibly moist, and Prime & Bond NT (Dentsply Detrey/ Germany) was applied. In Group 2, after acid conditioning, the cavity surface was air dried for five seconds, followed by application of Prime & Bond NT. In Group 3, 3% NaOCl (Hyposol, Prevest Denpro Ltd/India) was applied to the acid-conditioned cavity surface for two minutes. The surface was blot dried before bonding. In Group 4, after NaOCl treatment, the surface was air dried for five seconds, followed by application of the bonding agent. In Group 5, 10% sodium ascorbate (chemically pure) was applied to the NaOCl-treated acid conditioned tooth surface for one minute. The surface was blot dried before bonding. In Group 6, after sodium ascorbate treatment as in Group 5, the cavity surface was air dried for five seconds before bonding. The cavities were restored with the hybrid composite Spectrum TPH (Dentsply Detrey, Konstanz, Germany). The teeth were extracted immediately after restoration, and the specimens were prepared for microleakage testing using 2% methylene blue dye and for scanning electron microscopic evaluation. The results of the dye penetration were analyzed with Kruskal-Wallis non-parametric analysis followed by the Mann-Whitney U test at a significance level of p = 0.05. After acid etching, the conventional acid etched groups and groups with NaOCl treatment demonstrated extensive leakage. Sodium ascorbate treatment of the NaOCl-treated dentin significantly reduced microleakage. No statistically significant difference between moist and dry bonding was observed in all groups. Although resin tag penetration improved in both the NaOCl-treated and NaOCl/ascorbate-treated groups, an absence of gap at the resin dentin interface was observed only for the NaOCl/ascorbate-treated groups.     

In vitro evaluation of microleakage of a flowable composite in Class V restorations

The aim of this study was to evaluate microleakage around class V restorations using a flowable composite compared to a hybrid composite. Forty class V cavities were prepared on buccal and lingual surfaces of 20 human teeth, with occlusal and cervical margins at the enamel and cementum/dentin levels, respectively. Specimens were divided into 2 groups with 10 samples each. Group 1: buccal cavities received Paama 2 (conventional bonding agent) + Wave (flowable composite); lingual cavities were restored with Paama 2 + Glacier (hybrid composite). Group 2: buccal cavities received Optibond Solo (self-priming bonding agent) + Wave; lingual cavities were restored with Optibond Solo + Glacier. After being stored in distilled water and finished, the teeth were thermocycled, immersed in a 50% silver nitrate solution and embedded in resin. They were sectioned and the depth of tracer penetration was scored. The results were analyzed using Kruskal-Wallis and Wilcoxon tests. The restorations with flowable composite and those with hybrid composite from the same group showed similar results of microleakage for both occlusal and cervical margins. Optibond Solo improved the sealing of the restorations when compared with Paama 2 (p < 0.01). None of the restorative materials completely sealed the tooth/restoration interface at the cervical margins.     

Shear bond strength, microleakage, and confocal studies of 4 amalgam alloy bonding agents.

OBJECTIVE: This study was undertaken to determine the relative shear bond strengths and microleakage of 4 bonding agents to dentin and amalgam and to investigate the bonding to dentin through confocal laser scanning microscopy. METHOD AND MATERIALS: Sixty noncarious molars were restored with 1 of 4 different systems, and the shear bond strengths were determined. For the microleakage study, Class V amalgam restorations were placed in 60 noncarious teeth. The specimens were thermocycled, the teeth were sectioned, and dye penetration was assessed. For confocal examinations, the first component of the bonding adhesives was labeled with rhodamine B. Each of the adhesives was applied to 3 dentin specimens, which were examined under a confocal laser scanning microscope RESULTS: Of the 4 restorative systems tested, AmalgamBond Plus + HPA and Prime & Bond 2.1/base-catalyst showed significantly higher shear bond strengths. Prime & Bond 2.1/base-catalyst had the lowest microleakage value, which was significantly lower than that of AmalgamBond Plus + HPA and AmalgamBond Plus. AmalgamBond Plus + HPA had the highest variation in both the bond strength and microleakage values. Confocal laser scanning microscopy revealed tag formation, penetration of the bonding agents deep into the tubules, and hybrid layer formation for all 4 bonding systems. CONCLUSION: The 2 best systems, Prime & Bond 2.1/base-catalyst and, to a lesser extent, AmalgamBond Plus + HPA, utilized a supplemental bonding agent.