几种根管冲洗剂根管清洁效果的扫描电镜观察

为了比较ＥＤＴＡ、ＲＥＤＴＡ、ＥＤＴＡ加次氯酸钠以及次氯酸钠单独使用时清除玷污层的效果，采用离体牙根管预备配合使用少量冲洗剂根管内封入，并用扫描电镜进行观察。结果显示１５％ＥＤＴＡ与５．２５％ＮａＯＣｌ合用时效果最佳，且封入时间以４８ｈ为宜，５．２５％ＮａＯＣｌ清除玷污层效果最差，差异有显著性。综合分析认为１５％ＥＤＴＡ和５．２５％ＮａＯＣｌ交替冲洗根管并封入根管内是一种具有临床应用价值的新方法。     

不同根管冲洗剂对根管玷污层清洗效果的体外研究

目的 比较不同根管冲洗剂对根管内壁玷污层的清洗效果.方法 将32颗离体牙随机分成4组,每组8颗,A组0.9％生理盐水冲洗,B组3％双氧水冲洗,C组3％次氯酸钠冲洗,D组2％氯亚明冲洗.根管预备完成后,扫描电镜观察根管中1/3的玷污层去除情况,参考玷污层分级标准,对数据进行统计学分析,比较各组根管玷污层清洗效果.结果A、...     

比较不同冲洗技术去除老年人根管玷污层效果

目的：应用60℃NaOCl配合不同的冲洗技术对老年人离体牙根管进行冲洗,评估玷污层的清除效果。方法：将40颗取自老年人(60周岁以上)的完整上颌离体前牙,应用60℃NaOCl进行根管冲洗。按照不同的冲洗技术随机分为4组(n=10)：侧方开口冲洗器组、被动超声组(PUI组)、EndoActivator组、对照组,并评估玷污层清除情况。结果：比较4组不同的冲洗技术对老年人根管玷污层的去除情况：EndoActivator组、PUI组和对照组之间差异无统计学意义,且优于侧方开口冲洗器组(P<0.05)。分别比较4组组内不同的根管水平玷污层的去除情况：各组根上1/3优于根中1/3,根中1/3优于根尖1/3(P<0.05)。结论：60℃3%NaOCl作为基础冲洗液,17%EDTA作为最终冲洗液,不使用任何冲洗设备与辅助被动超声或EndoActivator对老年人根管进行冲洗玷污层清除效果相似,且均优于侧方开口冲洗器。     

根管冲洗剂对玷污层的作用

玷污层可阻碍药物进行深层消毒，降低充填材料与根管壁的密合性，使根尖微漏显著增加．导致根管治疗失败。根管冲洗是根管治疗过程中一个重要环节，能否有效去除玷污层是其关键之一。本文就次氯酸钠，螯合剂及有机酸等常用冲洗剂对玷污层的作用进行概述，可以看出，多种冲洗剂联合使用将更加有效地去除玷污层。     

一种新的根管冲洗剂——MTAD

与器械预备相伴的根管冲洗是根管预备过程的重要环节,冲洗液应当能够溶解坏死组织,有消毒杀菌作用,并且能够去除玷污层.本文将介绍一种新的根管冲洗剂--MTAD.MTAD是强力霉素、柠檬酸和清洁剂的混合物,它能有效去除玷污层,抗微生物作用强,细胞毒性小,临床使用安全.     

根管冲洗剂的研究进展

根管冲洗是根管预备中必需的环节。目前常用的根管冲洗剂的抗菌能力、清洁作用和组织相容性等各有优缺点,只有了解各种根管冲洗剂的特性,合理搭配使用,才能达到理想效果。     

EDTA在根管冲洗中的研究进展

乙二胺四乙酸(EDTA)与次氯酸钠(NaOCl)是临床常用的根管冲洗液.本文通过对EDTA与NaOCl联合使用机理的阐述,就其在不同pH值、不同浓度、不同操作时间及不同种类EDTA的盐溶液,对去除玷污层效果的影响和对牙本质硬度的影响,及其渗漏至根尖孔可能产生的负面影响的研究现状作一介绍.     

MTAD作为根管冲洗剂的效果评价

目的探讨应用MTAD作为根管冲洗剂去除根管壁玷污层的效果,以及对根管充填后根尖微渗漏的影响。方法采集因正畸或牙周病拔除的前磨牙,截冠后统一工作长度16 mm,按照冲洗液使用的不同,随机分为A、B、C 3组,每组12颗。A:生理盐水;B:MTAD;C:5.25%NaClO+15%EDTA。采用机用Protaper镍钛根管锉进行根管机械预备,分别用相应冲洗液冲洗,根管预备后每组4颗牙齿用于制备扫描电镜标本,观察根管表面玷污层和牙本质小管暴露的情况。每组剩余8颗进行根管充填,1周后,采用液体转移法,测量各样本根管微渗漏。实验数值采用SPSS 19.0软件包进行分析。结果 A组沉积大量玷污层,牙本质小管被遮蔽,B、C组玷污层得到有效的清除,牙本质小管开放。根管充填后,A组和B组之间,A组和C组间的微渗漏值有统计学差异(P<0.05),B组合C组之间无统计学差异(P>0.05),其中A组的微渗漏值最大。结论 MTAD冲洗剂可以替代5.25%NaClO+15%EDTA联用,能有效地去除根管充填过程中产生的玷污层,增强根管充填后的根尖封闭性。     

强酸性电解质水冲洗根管的清洁效果

目的：体外观察比较强酸性电解质水与其他3类冲洗剂及其方法在根管治疗术中的清洁效果。方法：40个新鲜拔除的单根、单根管牙,常规逐步后退法进行根管预备,按照不同的冲洗组合和方法随机分为5组进行根管预备后的冲洗,然后纵向劈开牙齿,扫描电镜观察根管壁的情况。结果：强酸性电解质水、EDTA均能有效去除根管玷污层,冲洗1 min、3 min与150 g/L EDTA冲洗1 min没有显著差别,前者与EDTA加次氯酸钠液配合使用组相比,根管壁的玷污层、细菌均得到有效清除。结论：强酸性电解质水结合超声振荡能有效地清除根管玷污层和细菌。     

Spreading of root canal irrigants on root dentine

The purpose of this study was to evaluate the spreading of root canal irrigants on human root dentine. The spreading of various solutions on dentine surfaces was measured after pre-treatment with various conditional solutions. Seven experimental groups were set based on the combination of conditioning solution-test solution: none-distilled water; none-6% sodium hypochlorite (NaOCl); none-14.3% ethylenediaminetetraacetic acid containing surfactant 0.084% cetrimide (Morhonine); NaOCl-NaOCl; NaOCl-Morhonine; Morhonine-Morhonine and Morhonine-NaOCl. After application of 0.1 mL of conditioning solution for 60 s, 0.5 microL of test solution was placed on dentine surfaces. Spreading of test solution was measured for 480 s to examine the size of the contact area ratio. Those at 300 s were compared among groups using Fisher's Protected Least Significant Difference (P < 0.05). It was concluded that the contact area ratio of Morhonine-NaOCl increased the most significantly among all the experimental groups.     

Highly concentrated EDTA gel improves cleaning efficiency of root canal preparation in vitro

Debris and smear layer, as a product of mechanical root canal instrumentation, reduce the effectiveness of pharmacological substances to prevent post-treatment diseases and impair direct contact of filling materials with a clean dentinal surface. The aim of this in vitro study was to investigate the presence and localization of debris and smear layer via scanning electron microscope analysis after standardized root canal preparation with different chelating agents. Dentin surfaces received treatment with: (1) 15% ethylenediaminetetraacetic acid (EDTA), (2) 18.6% EDTA (3) and 24% EDTA or without any demineralizing chemicals as control. Forty vertically split human premolars were sputtered and divided into coronal, middle, and apical sections, followed by a randomized, blinded score evaluation using five scores. Pairwise comparisons of all treatment groups against a control group have been performed by Mann–Whitney U test and the Kruskal–Wallis test. Debris grades showed no significant difference between the three regions of the root canals, except for 18.6% EDTA in the central third. Smear layer and smear plug removal was concentration-dependent. Removal of the smear layer in the three areas showed that there was a statistically significant difference between all parts when using 18.6% and 24% EDTA concentrations compared with the control. The best smear layer removal in the apical region was observed using a 24% EDTA gel as chelating agent and lubricant. The usage of EDTA gel ≥18.6% presented a better cleaning regime when compared to the control group.     

The effect of Morinda Citrifolia juice as an endodontic irrigant on smear layer and microhardness of root canal dentin

PurposeThe purpose of this study was to evaluate the effect of Morinda Citrifolia Juice (MCJ) on smear layer removal and microhardness value of root canal dentin in compared with various endodontic irrigants.Material and methodsEighty-four single-rooted human teeth were prepared to apical size of #35. Since decoronation, samples were divided into seven groups of 12 in each (n = 12). Specimens were finally irrigated by either 1: 2.5% NaOCl, 2: 6% MCJ, followed by a final flush of 17% ethylene diaminetetraacetic acid (EDTA), 3: 6% MCJ, 4: 2.5% NaOCl then17% EDTA, 5: MTAD, 6: 2% chlorhexidine (CHX), and 7: saline. After irrigation, all samples were subjected to Vickers microhardness test at 100 and 500-μm depths and then were examined under scanning electron microscopy (SEM) and ImageJ program was used to calculate open dentinal tubules. One way ANOVA and post hoc Tukey tests were used to reveal any significant differences among and between groups respectively.ResultsThe microhardness values at 100 μm and 500 μm for MTAD were significantly lower than for NaOCl + EDTA and MCJ + EDTA groups (p < 0.05). MCJ + EDTA, NaOCl + EDTA, and MTAD protocol significantly removed smear layer in compared with control group (p < 0.05), with no significant differences among these three groups.ConclusionsIt was concluded that 6% MCJ followed by a final flush of 17% EDTA can be regarded as an effective solution on smear layer removal without any adverse influence on microhardness property of root canal dentin.     

Effects of root canal irrigations on intracanal medication with calcium hydroxide effects in root external resorption models

Objective

The objective of the present in vitro study was to evaluate the influence of endodontic irrigation systems on the removal of smear layer and ion diffusion of calcium hydroxide through dentinal tubules in root external resorption models.

Appearance of the root canal walls after preparation with NiTi rotary instruments: a comparative SEM investigation

The aim of this study was to evaluate, in vitro, with scanning electron microscope (SEM), the appearance of root canal walls shaped by three different rotary NiTi techniques and one conventional manual technique in human extracted teeth. Four different instruments were used: K³, Hero 642, RaCe and K-file. Each sample was irrigated with 5 ml of 5% NaOCl and 5 ml of 3% H₂O₂ and EDTA, Rc-Prep (1 ml). Each sample was prepared for SEM observation and analyzed in the coronal, middle and apical third, comparing its aspect with a predefined scale of four different parameters: presence of smear layer, pulpal debris, inorganic debris and surface profile. The apical third showed significantly more pulpal and inorganic debris, smear layer and a high number of surface profile irregularities. No significant difference was found at the coronal, middle and apical thirds between manual and rotary techniques for inorganic debris, smear layer and surface profile. Much pulpal debris were found in the apical third for K³ and RaCe compared with Hero 642 and K-file. In conclusion, mechanical rotary techniques with NiTi instruments produced quite similar results compared with a conventional manual technique using K-files. The present study demonstrated that dentin and pulpal debris, the morphology of smear layer and surface profile were only partially influenced by the type of endodontic instruments. The apical third was the anatomical area with greater amount of debris and smear layer.     

Comparison of antibacterial and toxic effects of various root canal irrigants

AIM: To compare the antibacterial properties and toxicity of 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine gluconate and 0.2% chlorhexidine gluconate plus 0.2% cetrimide (Cetrexidin); Vebas, San Giuliano, Milan, Italy). METHODOLOGY: The antibacterial effects of the irrigants in vitro were examined after 5 min and 48 h in freshly extracted human teeth with single roots, whose canals were infected by Enterococcus faecalis ATCC 29212. In a separate in vivo study, bacterial culture samples were collected before treatment from the infected root canals of deciduous teeth containing necrotic pulp tissue. Irrigants were used to clean the canals which were then left empty for 48 h. Aerobic/facultative anaerobic and anaerobic bacterial growth were compared before and 48 h after irrigation. Finally, the toxic effects of the irrigants were assessed by injecting them into the subcutaneous tissues of rats. The inflammatory reactions that occurred 2 h, 48 h and 2 weeks after the injections were evaluated. RESULTS: In the laboratory study, the 2% chlorhexidine gluconate and Cetrexidin were significantly more effective on E. faecalis than the 5.25% NaOCl at 5 min (P < 0.05). Similarly, in the in vivo study, 2% chlorhexidine gluconate and Cetrexidin were significantly more effective on anaerobic bacteria than the 5.25% NaOCl at 48 h (P < 0.05). At the end of 2 weeks, the toxicity of the NaOCl solution was greater than that of the other irrigants (P < 0.05). CONCLUSIONS: Cetrexidin and 2% chlorhexidine gluconate were more effective, and had more residual antibacterial effects and lower toxicity than 5.25% NaOCl solution.     

Wettability of root canal sealers on intraradicular dentine treated with different irrigating solutions

Objectives

The aim of this in vitro study was to evaluate the wettability of AH Plus and ThermaSeal Plus sealers on intraradicular dentine treated with different irrigating solutions.

Methods

Fifty anterior teeth were decoronated and split longitudinally. Each root half was divided into 5 groups (n = 10). Group I: 5 mL of 2.5% NaOCl + QMix. Group II: 5 mL of 2.5% NaOCl + 17% EDTA. Group III: 5 mL of 2.5% NaOCl + 7% maleic acid. Group IV: 5 mL of 2.5% NaOCl. Group V: 5 mL of distilled water. Irrigation regimens were performed for 1 min. Each specimen was placed inside a Dynamic Contact Angle Analyser. A controlled-volume droplet of sealer was placed on each specimen and the static contact angle was analysed.

Results

The contact angle made by both sealers with EDTA-irrigated dentine was significantly larger when compared to the other irrigants (P < 0.05). For ThermaSeal Plus, contact angles produced on maleic acid-, NaOCl- and distilled water-irrigated dentine were not significantly different, but were all significantly larger than the contact angle produced on QMix-irrigated dentine (P < 0.05). For AH Plus, contact angles produced on NaOCl- and distilled water-irrigated dentine were not significantly different, but were significantly larger than those made by maleic acid and QMix.

Conclusion

When used as a final irrigant, QMix favours the wetting of root canal dentine by both AH Plus and ThermaSeal Plus sealers. Maleic acid shows a promising result when compared to EDTA and NaOCl. Wettability of both sealers is the worst on EDTA-irrigated dentine.

Clinical significance

The present study highlights the effect of newer endodontic irrigating solutions on the wettability of sealers on to the root canal dentine, which is required for obtaining good obturation seal.     

Improving the effect of NaOCl pretreatment on bonding to caries-affected dentin using self-etch adhesives

Objective

To evaluate the effect of sodium hypochlorite pretreatment on adhesion to normal and caries-affected dentin using self-etch adhesives.

Methods

Forty extracted human molars with coronal carious lesions were used in this experiment. The occlusal dentin surfaces including the caries-affected dentin in each group were treated as follows: group 1, rinsed with water; group 2, treated with 6% NaOCl for 15 s; group 3, treated with 6% NaOCl for 30 s; group 4, application with Accel for 30 s after NaOCl-30 s pretreatment. After rinsing with water and air-drying, the treated dentin surfaces were applied with self-etch systems (Bond Force and Clearfil Protect Bond) according to the manufacturers’ instructions, and built-up with resin composite. After 37 °C water storage for 24 h, the bonded normal or caries-affected dentin areas were isolated to create an hourglass configuration with a cross-sectional area of approximately 1 mm². The specimens were subjected to tensile stress at a cross-head speed of 1.0 mm/min.

Results

NaOCl-15 s pretreatment significantly improved the μTBS of both self-etch adhesives to caries-affected dentin, while the 30 s pretreatment did not affect them. For normal dentin, NaOCl-30 s pretreatment significantly reduced the μTBS of both self-etch adhesives although the 15 s pretreatment did not alter them. Furthermore, the application of Accel with a reducing effect increased the μTBS to normal and caries-affected dentin treated with NaOCl for 30 s.

Conclusions

The effects of NaOCl pretreatment on bonding of both self-etch adhesives were dependent upon type of dentin (normal and caries-affected dentin) and the treatment time.