Endosonics – The ultrasonic synergistic system of endodontics

Abstract Endosonics is an ultrasonic synergistic system of root canal instrumentation and disinfection. Specially made endosonic dies and diamond instruments are energized by means of a Cavitron ultrasound generator (above 20 kHz frequency). An endosonic insert is designed to allow the traditional endodontic irrigant, sodium hypochlorite, to pass through and along the endo-sonic files. The irrigant is activated by the ultrasonic energy imparted from the energized instruments and the root canal becomes an ultrasonic bath. Thus, endosonics is a synergistic system. The ultrasonic energy makes the files vibrate and oscillate, facilitating the instrumentation of the root canal and, in addition, activates the irrigant for canal disinfection.     

被动超声冲洗对弯曲根管的碎屑清理能力和根管形态的影响

目的: 评价被动超声冲洗在弯曲根管内碎屑清理能力和根管偏移量。方法: 选取下颌磨牙近中弯曲根管36个,弯曲度在25°以上,以机用 XP-endo Shaper根管锉预备根管。根据弯曲长度（curved length,CL）和冲洗方式分为A1组（CL>3 mm,注射器冲洗）、B1组（CL>3 mm,超声K锉冲洗）、C1组（CL>3 mm,irrisafe超声锉冲洗）、A2组（CL<3 mm,注射器冲洗）、B2组（CL<3 mm,超声K锉冲洗）和C2组（CL<3 mm,irrisafe超声锉冲洗）,每组6个样本。对所有样本冲洗前、后进行Micro-CT扫描,计算冲洗后根管内体积增加量和根管偏移量。采用SPSS 22.0软件包对数据进行统计学分析。结果: 在CL>3 mm的根管根尖区,PUI+irrisafe组的根管体积增量显著高于PUI+K锉和注射器冲洗（P<0.05）,并且在距离根尖孔5 mm处PUI+irrisafe形成的根管偏移量显著低于PUI+K锉（P<0.05）;与注射器冲洗相比无显著差异（P>0.05）。在CL<3 mm的根管中,PUI+irrisafe组和PUI+K锉组的根管体积增量均显著高于注射器冲洗（P<0.05）,但根管偏移量与注射器冲洗无显著差异（P<0.05）。结论: 在弯曲长度较大的根管中,被动超声冲洗结合预弯锉可获得更好的清理效果;而在弯曲长度较小的根管中,被动超声冲洗结合K锉和预弯锉均安全有效。     

An SEM study of the effects of different irrigation sequences and ultrasonics

The root canals of 30 extracted human teeth with single canals were prepared biomechanically with hand instruments using a flaring technique. Three different irrigation regimes were used, with and without ultrasonic activation of a root canal file. The six irrigation sequences used in this study were as follows: Savlon, Savlon with ultrasound, EDTAC/NaOCl/EDTAC, EDTAC/NaOCl/EDTAC with ultrasound, NaOCl/EDTAC/NaOCl, and NaOCl/EDTAC/NaOCl with ultrasound. Scanning electron microscopic (SEM) examination of the prepared root canal walls showed a complete smear layer when Savlon was used. Ultrasound reduced the amount of smear with Savlon, but did not do so significantly with the other irrigation regimes. The most effective irrigation regime for removing smear layer and other debris was EDTAC/NaOCl/EDTAC. In all groups there was a significant decrease in cleaning efficiency as the apical end of the canal was approached.     

From files to SAF: 3D endodontic treatment is possible at last

3D cleaning, shaping and obturation of root canals has always been the desired goal of endodontic treatment which in many cases is difficult to attain. The introduction of NiTi rotary files made a major change in endodontic practice, making treatment easier, safer and faster. Nevertheless, after 16 years of intensive development, most of these instruments still share several drawbacks, the major one being the inability to three-dimensionally clean and shape oval root canals. The Self-Adjusting File (SAF) System was designed to overcome many of the current drawbacks of rotary file systems. It is based on a hollow, highly compressible file that adapts itself three-dimensionally to the shape of a given root canal, including its cross section. The file is operated with vibratory in-and-out motion, with continuous irrigation delivered by a peristaltic pump through the hollow file. A uniform layer of dentin is removed from the whole circumference of the root canal, thus achieving the main goals of root canal treatment while preserving the remaining root dentin. The 3D scrubbing effect of the file, combined with the always fresh irrigant, result in unprecedentedly clean canals which facilitate in turn better obturation. More effective disinfection of flat-oval root canals is another goal which is simultaneously attained. The safety of the root-canal treatment is also greatly enhanced by the high mechanical stability of the SAF and by using a new concept of no-pressure irrigation. The SAF System gets the operator much closer to the long-desired goal of 3D root-canal treatment.     

Scanning electron microscopy analysis of RinsEndo system and conventional irrigation for debris removal

A new device for irrigation, which presents hydrodynamic activation based on the pressure-suction technology, has recently been introduced to the market: the RinsEndo system. This study compared the efficacy of the RinsEndo system and conventional (manual-dynamic) irrigation in the removal of debris from the root canal walls, using scanning electron microscopy (SEM). Twenty mandibular premolars with completely formed roots were selected and randomly divided into group 1 (irrigation with the RinsEndo system) and group 2 (conventional irrigation). The canals were irrigated with 1 mL of saline at each change of instrument. Instrumentation started with a #15 K file and continued up to a #40 K file, which was standardized as the working length instrument. Then, the teeth were sectioned in buccolingual direction and the halves were sputter-coated with gold and examined by SEM. The apical, middle and cervical root canal thirds were evaluated, and the results were analyzed statistically by the Mann-Whitney test for comparison between methods, Kruskal-Wallis test for comparison among thirds, and Miller test for individual comparisons. A significance level of 5% was set for all analyses. The results did not show significant differences (p>0.05) between methods at each third and among thirds for each technique analyzed individually. In conclusion, there was no difference in the cleaning ability of the RinsEndo system and conventional irrigation.     

Light and scanning electron microscopic evaluation of Glyde File Prep in smear layer removal

AIM: To evaluate the effectiveness of Glyde File Prep used in conjunction with sodium hypochlorite irrigation in the removal of smear layer produced during root canal instrumentation. METHODOLOGY: Thirty-nine extracted human teeth with single root canals were used. Access cavities were prepared and the teeth divided into three groups of 13 teeth each. Each group was treated by one of the three different regimes of irrigation and conditioning during root canal instrumentation. Group A: 0.5 mL of 1% NaOCl irrigation after each file size with an additional final irrigation of 10 mL 1% NaOCl; group B: 0.5 mL of 1% NaOCl irrigation after each file size with an additional final irrigation of 10 mL 17% EDTA; group C: Glyde File Prep coated on each instrumentation file used in conjunction with 0.5 mL 1% NaOCl irrigation after each file size and an additional final irrigation of 10 mL 1% NaOCl. The teeth were then longitudinally grooved and sectioned. Root canal cleanliness was evaluated with the aid of a Nikon light microscope (x40 and x100) and scanning electron microscope (x1000 and x3000). The debris scores obtained at three canal regions were compared statistically within the same group and among different groups using repeated measurements of analysis of variance (anova) with Bonferroni adjustments and anova with posthoc Tukey HSD, respectively. RESULTS: The canals treated with EDTA and Glyde File Prep were significantly cleaner than those treated with NaOCl alone. The apical region of the root canals generally displayed more residual smear layer, but the difference was not significant. CONCLUSIONS: Used in conjunction with NaOCl irrigation, Glyde File Prep was effective in removing smear layer produced during root canal instrumentation.     

Canal Finder System 89!!! Improvements and indications after 4 years of experimentation and use

Actually, the CANAL FINDER SYSTEM is the only entirely automated endodontic device. After four years of existence, many evaluations were able to show the qualities of this system regarding root canal penetration, cleaning and shaping. The earlier concerns such as ergonomical problems were solved: automated extraction of the K-file, automated sodium hypochlorite irrigation. A new file was created, particularly well adapted to the root canal shaping of curved canals. This addition has improved the efficiency of the automated instrumentation. The CANAL FINDER SYSTEM has reached a maturity level permitting an excellent reliability and ease of use.     

不同冲洗技术去除模拟牙内吸收窝洞中氢氧化钙糊剂效果的体外研究

目的：评估不同冲洗技术去除模拟牙内吸收窝洞内氢氧化钙糊剂的效果。方法：收集110颗单根离体牙, ProTaper预备至F3。将牙根纵向劈成两半,制备标准化的模拟牙内吸收窝洞后将两半牙根复位。5颗牙齿作为阴性对照组,不向根管内导入氢氧化钙糊剂。105颗牙齿导入氢氧化钙糊剂,其中5颗作为阳性对照组不去除根管中的氢氧化钙糊剂,其余100颗牙齿根据使用的不同冲洗技术随机分成5组（n＝20）：常规冲洗针头冲洗组、主尖锉清理组、根管刷刷洗组、超声荡洗组、音波震荡组。体式显微镜下观察使用5种不同冲洗技术去除模拟牙内吸收窝洞后氢氧化钙糊剂剩余的量,使用van der Sluis 4级评分系统进行评分,Kruskal－Wallis检验以及Mann－Whitney检验（P＜0．05）对数据进行统计分析。结果：超声荡洗组、音波震荡组较其他组模拟牙内吸收窝洞内氢氧化钙糊剂剩余的量较少（P＜0．05）。超声荡洗组与音波震荡组间无明显统计学差异（P＞0．05）。常规冲洗针头冲洗组、主尖锉清理组和根管刷刷洗组间无明显统计学差异（P＞0．05）。结论：超声荡洗和音波震荡去除模拟牙内吸收窝洞内氢氧化钙糊剂效果较好。     

A survey of interfacial forces used during endosonic instrumentation of root canals

AIM: The aim of this in-vitro study was to measure interfacial forces acting between root canal dentine and ultrasonic files during endosonic instrumentation. METHODOLOGY: Single-rooted teeth were mounted on a cantilevered aluminium beam to which two pairs of single element strain gauges were joined in a half-bridge configuration mounted at right angles to each other. The strain gauges were connected to an analogue-to-digital converter fitted in a microcomputer via a conditioning amplifier. This enabled strains to be recorded as a function of interfacial forces over a period of time. Twenty operators instrumented root canals using sizes 15, 20 and 25 ultrasonically energized K-type files. The lateral forces generated were calculated. RESULTS: The mean interfacial forces used varied widely between operators and files, ranging from 18 g to 149 g, but there was a consistency in the relative magnitude for each operator. The average force used by the operators increased with file size; the differences between file sizes were significant (P < 0.05). CONCLUSIONS: The range of forces measured is broader than previously reported and may have a bearing on possible uncontrolled dentine removal, even during ultrasonically activated irrigation.     

根管显微镜下上颌第二磨牙根管的再治疗

目的：总结应用根管显微镜和超声器械对上颌第二磨牙根管再治疗的临床疗效。方法：收集上颌第二磨牙初次治疗失败病例80例,显微镜下记录初次治疗失败原因,应用根管显微镜和超声技术疏通根管,机用镍钛锉冠向下法预备根管,侧方加压和垂直加压法充填根管,拍X线牙片记录再治疗成功率。结果：80个患牙再治疗成功71个,成功率88.7%。半年后随访,成功率88.2%。结论：上颌第二磨牙因其根管存在融合、变异、根管过弯等因素,易导致初次治疗时根管遗漏、台阶形成、器械折断、根管侧穿以及根管钙化,造成初次根管治疗失败。应用根管显微镜和超声技术对其进行再治疗能获得满意的疗效,但应正确使用超声器械,避免根管侧穿的发生。     

三维自调节根管预备锉

镍钛旋转器械预备后的根管横切面为圆形,普遍存在近远中壁过度预备,颊舌侧壁和靠近峡区的泪滴状区域及峡区未被清理等问题,而三维自调节锉（SAF）则可解决上述问题。SAF由中空可压缩的薄镍钛网丝制作而成,不仅在纵向上能顺应根管弯曲方向,在横断面上亦能适应根管形态,自动调整为圆形、扁形或椭圆形等对根管壁牙本质进行均匀的往复式切削。SAF连接冲洗系统VATEA后以持续低压传递冲洗液至根管深处,收到机械预备和化学预备同期进行的效果,有利于去除涂层,遗留的未预备面积较旋转器械少,但其去除根管内感染物质的能力尚存争议：SAF较旋转器械更容易清除椭圆形根管中的细菌,但却不能有效地预备根尖段,冲洗液也难以传递至根尖区域,导致其不能有效去除根管壁碎屑、涂层,亦不能有效地清除根尖的感染细菌。SAF的通畅能力较弱,在再治疗中主要起辅助冲洗的作用,可以去除更多的牙胶残留物。SAF不易出现器械完全分离,偶尔网状镍钛丝的一端分离,另一端仍与器械主体相连,不会出现分离端遗留根管内造成根管堵塞。以SAF联合手用锉预备根管,牙本质壁则几乎无任何微裂纹。简而言之,SAF的出现对于进一步研发和改良器械,提高根管预备效率,减少并发症具有重要的意义。     

Intra-canal cutting ability of MM 1500 files

The aims of this study were to develop a model system capable of monitoring lateral forces during root canal preparation and to measure the cutting ability of files activated by the MM 1500 sonic handpiece. Forces were monitored by a calibrated model system which utilized a combination of spring steel beams fitted with strain gauges, these were interfaced through two strain gauge amplifiers to an x-y recorder. Single rooted canine teeth ( n = 36; 32 experimental, four control) were mounted in a two-part acrylic mould (which was an integral part of the model system) prior to sectioning horizontally 11 mm from the tooth apex. A 2⁴ full factorial experiment with two replications was performed. Four variables were selected for evaluation, load (50 and 100 g), power (air inlet ring half or fully open), file type (Heliosonic or Shaper) and stroke rate (1 or 2 cycles per second). A new file (size 25) was used for 1 min in each canal with water irrigation. The control group was not instrumented. The cross-sectional root canal area was measured before and after instrumentation using image analysis and increase in area was used as an indication of cutting ability. The results showed that the increase in load, power and the Shaper file all produced a significant increase in cutting ability (ANOVA, P < 0.001). However, stroke rate was not found to have a significant effect ( P > 0.05). None of the interactions between the variables were significant and there was no significant difference in the control group ( P > 0.05). In conclusion, this work has developed a model system to monitor lateral forces and has shown that instrument design and operator usage affect dentine removal from a root canal wall.     

根管预备后超声冲洗的临床研究

目的 对不同方法根管预备后超声冲洗进行临床评估。方法 将121例患者144颗患牙，随机分成四组：手用不锈钢K锉组；手用不绣钢K锉＋超声冲洗组；机用不锈钢K锉组；机用不绣钢K锉＋超声冲洗组。手用不绣钢K锉采用逐步深入法预备根管，机用不绣钢K锉采用逐步后退法预备根管。比较四组根管预备后疼痛发生情况率、根管充填质量、根尖偏移和倜枝根管充填情况，以及根管充填一年疗效观察。结果各组根管预备后疼痛无显著性差异（P〉0．05）。超声组侧枝根管充填率高于单纯手用和机用组。术后一年复查98颗，相应各组无显著性盖异（P〉0．05）。结论 根管预备后超声冲洗，对降低术后疼痛及提高临床治疗有效率无明显效果；但可以提高侧枝根管充填率。     

不同根管冲洗方式对根管充填后管壁粘接强度影响研究

目的　采用推力实验检测不同冲洗方式对根管封闭剂AH-Plus及iRoot SP与根管壁粘接性能的影响，同时比较两种根管封闭剂的粘接强度。方法　收集2013年在中国医科大学附属口腔医院就诊患者拔除的56颗上颌单根管前磨牙。根据根管冲洗方式的不同，将所有样本随机均分为A ~ D组，每组14颗。A组为次氯酸钠（NaClO）溶液注射冲洗根管，B组为NaClO配伍乙二胺四乙酸（EDTA）溶液注射冲洗根管；C组为NaClO配伍EDTA溶液注射冲洗后辅以超声冲洗根管；D组为NaClO配伍EDTA溶液注射冲洗和超声冲洗根管后，使用氯己定（CHX）溶液再次冲洗根管。根据根管封闭剂的不同，每组又均分成2个亚组，分别使用AH-Plus和iRoot SP根管封闭剂。待根管充填后，采用推力实验比较各组的粘接强度。结果　不同根管封闭剂对粘接强度无明显影响（P > 0.05），不同的冲洗方式对粘接强度有影响（P < 0.05）。B1、B2组的粘接强度分别高于A1、A2组，差异有统计学意义（均P < 0.05）；C1、C2组的粘接强度分别高于B1、B2组，差异有统计学意义（均P < 0.05）；而D1、D2组的粘接强度分别与C1、C2组比较，差异无统计学意义（P > 0.05）。结论　采用NaClO配伍EDTA溶液作为根管冲洗液并辅以超声冲洗技术能有效增加根管封闭剂与根管壁的粘接强度，而CHX溶液做为最后一步根管冲洗液对根管封闭剂粘接强度的影响不大。iRoot SP及AH-Plus与根管壁的粘接强度无明显差别，均可作为根管封闭剂应用于临床。     

Passive ultrasonic irrigation of the root canal: a review of the literature

Ultrasonic irrigation of the root canal can be performed with or without simultaneous ultrasonic instrumentation. When canal shaping is not undertaken the term passive ultrasonic irrigation (PUI) can be used to describe the technique. In this paper the relevant literature on PUI is reviewed from a MEDLINE database search. Passive ultrasonic irrigation can be performed with a small file or smooth wire (size 10-20) oscillating freely in the root canal to induce powerful acoustic microstreaming. PUI can be an important supplement for cleaning the root canal system and, compared with traditional syringe irrigation, it removes more organic tissue, planktonic bacteria and dentine debris from the root canal. PUI is more efficient in cleaning canals than ultrasonic irrigation with simultaneous ultrasonic instrumentation. PUI can be effective in curved canals and a smooth wire can be as effective as a cutting K-file. The taper and the diameter of the root canal were found to be important parameters in determining the efficacies of dentine debris removal. Irrigation with sodium hypochlorite is more effective than with water and ultrasonic irrigation is more effective than sonic irrigation in the removal of dentine debris from the root canal. The role of cavitation during PUI remains inconclusive. No detailed information is available on the influence of the irrigation time, the volume of the irrigant, the penetration depth of the instrument and the shape and material properties of the instrument. The influence of irrigation frequency and intensity on the streaming pattern as well as the complicated interaction of acoustic streaming with the adherent biofilm needs to be clarified to reveal the underlying physical mechanisms of PUI.     

The role of mechanical instrumentation in the cleaning of root canals

The cleaning and shaping of the root canal is a key procedure in root canal treatment. The aim of cleaning is the removal of tissue remnants and bacterial biofilms in order to allow close adaptation of the root filling to the canal walls. In simple straight canals with a round cross‐section, this aim is easily attained by mechanical instrumentation and irrigation. The task of cleaning presents a greater challenge in oval canals, curved canals, and in canal systems that contain an isthmus. In areas that are inaccessible to mechanical instrumentation, the cleaning greatly depends on the action of sodium hypochlorite, which is used to dissolve and remove all of the remaining tissues and bacterial biofilms. Traditional irrigation with syringe and needle is often ineffective in cleaning such inaccessible areas. Newer irrigation methods allow for better cleaning by facilitating a more effective flow of irrigants; nevertheless, adequate, larger, mechanical preparations are required for the effective use of these methods. An alternative approach is to use a hollow file that adapts itself to the cross‐section of the canal, without excessive enlargement of the canal, thus allowing mechanical scrubbing of the walls with a continuous flow of the irrigant through the file. All cleaning methods reach their limit in cases of long narrow isthmuses that are often inaccessible to mechanical instrumentation; adequate instrumentation is, however, a prerequisite for all cleaning methods.     

A review of the prognostic value of irrigation on root canal treatment success

The aim of this review is to discuss the requirements for effective irrigation of the root canal system and its role in treatment outcome. A review of the literature regarding irrigants, methods of irrigation and regimens was undertaken. It indicates that irrigation is comprised of a multitude of factors, and that effective irrigant delivery and agitation achieves mechanical, chemical and microbiological functions, which are prerequisites for obtaining a clean canal system. However, most studies are ex vivo and assess intermediate outcome values rather than treatment success. Additionally, there is an absence of high‐level evidence evaluating the effect of irrigation on the outcome of root canal treatment. Therefore, citing irrigation as a significant factor that affects root canal treatment success cannot be done. This highlights the need to further investigate the prognostic value of irrigation on root canal treatment success.     

机用镍钛器械根管预备过程中加入连续根管外冲洗对根管内液体置换的影响

目的: 评估机械预备过程中加入连续根管外冲洗对根管内液体置换的影响。方法: 根据根管预备过程中是否加入连续根管外冲洗,将60个标准化树脂模块分为5个实验组。在标准化树脂模块中注入纯黑墨水,完成各实验组的预备和冲洗方案后,测量每个实验组标化根管模块内剩余液体的吸光度（A）值,判断根管内液体置换情况;同时计算流体力学模型模拟根管锉在根管内做上下运动时根管内液体的流场。采用SPSS 19.0软件包对数据进行统计学分析。结果: 机动预备过程中加入连续根管外冲洗的3个实验组,根管内剩余液体的A值显著低于不加入根管外冲洗的实验组（P<0.05）,但3个实验组组间无显著差异（P>0.05）。计算流体力学模型显示,加入连续根管外冲洗后,在根管中部存在液体的“有效返流区”,部分置换根管内液体;并且外冲洗进入根管内的液体通过锉的上下运动可以被输送至根尖区。结论: 机动预备过程中连续根管外冲洗进入根管内的液体,可部分替换原根管内溶液,稀释、改善根管内环境,对后续常规根管冲洗起到辅助作用。     

Dynamic recording of irrigating fluid distribution in root canals using thermal image analysis

AIM: To investigate the influence of the size and the depth of insertion of irrigating needles, and the diameter of the master apical file on flow distribution during fluid irrigation in root canals. METHODOLOGY: Stepback canal instrumentation was employed on seven extracted human single canal teeth. The size of the master apical files ranged from sizes 25, 30, 35, 40, 45, 50 to size 80 within the seven teeth, respectively. A thermal imaging system (ThermaCAM; National Instruments Co., Austin, TX, USA) was used to record the dynamic fluid distribution following root canal preparation. The dynamic fluid distribution was analysed during irrigation by insertion of different irrigating needle tips (23, 25 and 27 gauge) at various depths (3, 6 and 9 mm) from the root apex. The whole process of irrigation was recorded by a video camera and analysed by two observers separately. The success of the irrigation process was defined when the irrigant was able to flow into to the apical region immediately after injection. RESULTS: The aqueous irrigant was flushed into the apical region when a size 27 gauge irrigating needle was placed into a size 30 canal at a point 3 mm from the apical stop. When the same needle tip was placed 6 mm from the root canal apex, successful irrigation was achieved only in the canals prepared to size 50 or larger. When a size 25 gauge irrigating needle was placed 3 mm from the working length, the canal size had to be no <45 to allow for successful irrigation. When a size 23 gauge needle was placed at the same position, the canal needed to be prepared to size 50 to allow thorough irrigation of the apex. At 9 mm from the apical stop, none of the irrigating needles could achieve successful irrigation of any canal size. CONCLUSION: The flow distribution of root canal irrigation can be affected adversely by large diameter irrigating needles, by greater distances between the needle tip and the apical stop, and by narrow root canals.     

Histological analysis of the cleaning capacity of nickel-titanium rotary instrumentation with ultrasonic irrigation in root canals

This study evaluated, histologically and morphometrically, the cleaning capacity of rotary instrumentation in root canals using the Profile system with ultrasonic irrigation. Twelve single-rooted mandibular incisors were divided randomly into three groups according to the irrigation method tested. The canals in the teeth were instrumented using Orifice Shapers, taper 0.6 and 0.4 in the cervical third, and up to a #35 file in the apical third. One per cent sodium hypochlorite was used as the irrigating solution. Group I: canals were irrigated with 5 ml of solution, using a Luer-Lok syringe, between each file. Group 2: canals were irrigated with the solution and instrumented using ultrasound for I min between each file. Group 3: canals were irrigated with 5 ml of solution with Luer-Lok syringe, between each file, and final irrigation using ultrasound for 3 min. After chemo-mechanical preparation, the apical thirds of the teeth were submitted for histological processing. Morphometric analysis was performed using an optical microscope with 40x magnification and a grid. The results showed statistical difference at the 5% level between the methods used for irrigation. Rotary instrumentation with Profile system NiTi files and ultrasonic irrigation for 3 min was more effective in cleaning root canals when the different methods were compared.