两种侧方加压器进入弯曲根管深度的实验研究

目的比较国产镍钛(NiTi)和不锈钢(SS)侧方加压器在树脂模拟弯曲根管中的进入深度。方法选择已预备的树脂模拟弯曲根管(35°)20个,随机分成两组,即SS侧方加压器组(SS组)和NiTi侧方加压器组(NiTi组),分别测定在空根管内插入两种侧压器达工作长度时所需压力值;放入主牙胶尖,测定侧压器距工作长度3mm时的压力值;放入主牙胶尖,使用15N的压力,记录两种侧压器进入根管的深度。结果在空根管中,插入NiTi侧压器所需的平均压力为2.72N,明显低于SS侧压器的7.48N(P<0.01)。在有主牙胶尖的根管中,NiTi侧压器所需的平均压力为36.3N,明显低于SS侧压器的48.7N(P<0.01)。15N压力时,NiTi侧压器插入根管的平均深度为13mm;而SS侧压器进入的深度约为12mm(P<0.01)。结论国产NiTi侧压器在弯曲根管中较SS侧压器能获得较好的进入深度和较小的所需压力。     

比较两种锥度牙胶尖侧方加压的充填质量

目的比较0.02和0.04锥度主牙胶尖在不同弯曲度根管中的充填质量。方法选择40颗离体单根管的下颌前磨牙,依据根管弯曲度随机分为两组;机用镍钛ProFile器械预备根管,所有根管使用镍钛侧压器及0.02或0.04锥度主牙胶尖冷牙胶侧方加压技术充填;距根尖2和4mm处片切,记录图像并分析。结果在距根尖2mm处、弯曲度≤20°时,0.04主牙胶尖的PGP明显高于0.02主牙胶尖(P<0.05);但在弯曲度>20°时,两种锥度主牙胶尖的PGP无显著性差异;距根尖4mm处,组间PGP均无显著性差异。结论选用与根管锥度相近的主牙胶尖进行根管充填,能获得较好的充填质量。     

常温流动牙胶Guttaflow充填根管密合性的体外评价

目的 体外评价常温流动牙胶(Guttaflow)充填根管的致密性。方法 选择60个单根管下颌第一前磨牙,使用ProTaper冠向下法预备根管,然后随机分为3组进行根管充填。组1:以Guttaflow(加06锥度单牙胶尖)根管充填;组2:连续波热牙胶根管充填;组3:冷侧压法根管充填。然后在距根尖狭窄2、4、6、8mm处垂直于牙体长轴切开牙体,体视显微镜下观察切片中根管充填的情况,并采集图像,利用图像分析软件计算根管充填物中牙胶面积的百分比(PGP)。结果 在距根尖2mm和4mm处Guttaflow组的PGP明显高于热牙胶组和冷侧压组P<0.05),而热牙胶组和冷侧压组无显著差异(P>0.05)。在距根尖6mm和8mm处,Guttaflow组与热牙胶组无显著差异(P>0.05),但两者都高于冷侧压组P<0.05)。结论 Guttaflow根管充填法充填具有很好的密合性。     

GuttaFlow常温流动牙胶充填下颌第二磨牙C形根管密合性的评价

目的评价GuttaFlow常温流动牙胶用于下颌第二磨牙C形根管充填密合性。方法收集63颗具有C形根管的下颌第二磨牙,Hero shaper镍钛根管预备后,随机分为3组,分别采用GuttaFlow常温流动牙胶、EQ plus热牙胶和冷侧压充填。然后距根尖2、4、6、8 mm处垂直于牙体长轴片切牙齿,体视显微镜下观察剖面,并采集图像,利用图像分析软件计算根管充填物中牙胶面积的百分比(PGP),评价充填牙胶和根管壁密合性。结果 GuttaFlow常温流动牙胶在距根尖2、4 mm处充填密合性优于热牙胶和冷侧压。在6、8 mm处GuttaFlow与热牙胶的充填密合性无明显可见差别,但均好于冷侧压组。结论 GuttaFlow常温流动牙胶在用于充填下颌第二磨牙C形根管时,具有良好的密合性。     

连续波热牙胶在后牙弯曲根管治疗中的作用

目的：评价连续波热牙胶根管充填技术（continuous wave of condensation technique,CW）充填后牙弯曲根管的效果。方法：选取2008年6月～2010年1月确诊为牙髓根尖周病的后牙弯曲根管60例,随机分为三组（每组各20例）,实验组分别采用连续波热牙胶、ObturaⅡ、冷牙胶侧压三种方法充填根管,记录单个根管的根管充填时间,根充后即刻拍X线牙片评价根充效果,术后半年定期复查评价疗效。比较三种充填方法的根充时间、充填效果以及疗效。结果：连续波热牙胶组根管充填时间少于ObturaⅡ与冷牙胶侧压组,充填效果优于冷牙胶侧压组,疗效优于ObturaⅡ组与冷牙胶侧压组。结论：连续波热牙胶根管充填适用于后牙弯曲根管,操作快速有效,是一种值得在临床推荐使用的根管充填方法。     

ObturaⅡ&System B与Thermafil在扁根管内断离器械旁路充填的实验研究

目的:比较热塑牙胶充填(ObturaⅡ&System B和Thermafil)与冷牙胶侧方加压充填在扁根管内器械断离行旁路根管充填的效果。方法:将60颗扁根管离体下颌第一前磨牙随机分为3组,每组20颗牙。将新的15#不锈钢K锉(25 mm)断离在距根尖4 mm处,断离长度3 mm;从断离器械旁用Mtwo镍钛锉配合vdw.silver机用马达行根管旁路预备。在手术显微镜下分别采用ObturaⅡ&System B、Thermafil与冷牙胶侧方加压旁路充填。在距根尖2、5、8 mm处横断牙根,电子显微镜下记录在距根尖5 mm处断离器械与根充材料之间的缝隙,充填后根管内残余的空隙;分别记录在距根尖2 mm与8 mm处牙胶、空隙与糊剂占根管横断面的比例,分析不同充填方式的效果。结果:在离体的条件下,热牙胶充填在扁根管内器械断离后行旁路根管充填的效果优于冷侧压充填(P<0.05),ObturaⅡ&System B优于Thermafil,但无统计学差异(P>0.05)。结论:当器械断离在扁根管内,从断离器械旁建立通路进行根管预备,ObturaⅡ&System B充填,可达到严密封闭根管的目的。     

三种热牙胶根管充填技术牙胶充填面积百分数的比较研究

目的:比较3种热牙胶根管充填术后牙胶密度即牙胶充填而积百分数(percentage of gutta-percha-filled area,PGFA),评价3种热牙胶充填技术的充填效果.方法:采用人完整单根管离体牙40颗随机分成4组,根管预备后分别采用冷牙胶侧向加压法、热牙胶垂直加压法、热塑牙胶注射加压法(Obtura Ⅱ)和超声振动侧向加压法进行根管充填.每个根管分别在距离解剖根尖3、6和9 mm处横断,通过图像分析软件记录根管横断面积和牙胶充填的面积,计箅出牙胶充填面积百分数.结果:热牙胶垂直加压组和Obtura Ⅱ组的PGFA显著高于冷牙胶侧压组和超声侧压组(P＜0.05),热牙胶垂直加压组和Obtura Ⅱ组的PGFA之间无显著性差异(P＞0.05),且与根管充填的深度也无明显相关性(P＞0.05).热牙胶垂直加压组和Obtura Ⅱ组的PGFA在9 him和3 mm处明显大于冷牙胶侧压和超声侧压组(P＜0.05);在6 mm处,3种热牙胶的PGFA无显著性差异(P＞0.05).超声侧压组的PGFA与根管深度明显相关(P＜0.05).结论:热牙胶垂直加压法和Obtura Ⅱ允填后牙胶密度高,在9 mm和3mm处效果优于超声振动侧向加压法.超声振动侧向加压法充填效果受到根管深度影响.     

BeeFill~（TM） 2in1热牙胶根管充填系统根管封闭性的体外研究

目的：研究BeeFill TM2in1热牙胶根管充填系统对扁形根管的充填效果。方法：将20颗根管的近远中径与颊舌径之比小于0.5的单根管前磨牙,根管预备后,随机分别采用冷牙胶侧方加压充填术和BeeFill TM2in1热牙胶根管充填系统行根管充填。充填后的样本自根尖向冠方垂直于牙体长轴每间隔1mm制备横切片。体视显微镜下观测各横截面中是否存在空隙并计算空隙面积。结果：BeeFill TM2in1组空隙发生率、空隙面积的百分比均低于冷牙胶侧压组并存在统计学差异性;BeeFill TM2in1组在各层次横截面的空隙面积百分比平均值均低于冷牙胶侧压组并存在统计学差异性。结论：和冷牙胶侧方加压充填术相比,BeeFill TM2in1热牙胶根管充填系统在封闭扁形根管方面具有明显优势。     

System-B充填技术对模拟侧支根管充填效果的体外评价

目的:研究System-B连续波垂直加压充填技术对不同部位、不同直径侧支根管的充填情况.方法:选取人类单根管离体牙40颗,随机分为2组.根管预备后,在距根尖3mm、6mm、9mm处制备8#及15#K锉直径的人工侧支根管,分别用System-B连续波垂直加压充填技术和传统冷牙胶侧压充填法进行充填.制备成透明牙后,在体视显微镜下观察侧支根管的充填情况,采用SPSS13.0软件包对2组的充填效果进行比较.结果:System-B连续波垂直加压充填技术组和冷牙胶侧方加压充填技术组对侧支根管的充填率分别是85.00%和49.17%(P<0.05).System-B连续波垂直加压充填技术组对距根尖孔6mm、9mm处的侧支根管充填率及进入侧支根管充填物长度均优于3mm处(P<0.05),而6mm与9mm处的侧支充填,无论充填率或是充填长度,两者均无显著性差异(P>0.05);侧支根管充填的充填长度显示,直径较大的15#K锉组优于直径较小的8#K锉组(P<0.05).结论:System-B连续波垂直加压充填技术对侧支根管的充填效果优于冷牙胶侧压充填技术,其对不同部位及不同直径的侧支根管的充填效果也有差别.     

C型先锋锉和乙二胺四乙酸分次疏通磨牙弯曲钙化根管的临床研究

目的探讨疏通磨牙弯曲钙化根管的治疗方法。方法实验组选取70例患者72颗磨牙根管中、重度弯曲且下段钙化堵塞的根管136个．采用c型先锋锉结合乙二胺四乙酸（EDTA）制剂分次疏通弯曲钙化根管，机动镍钛根管器械扩大并行冷牙胶侧压充填根管。对照组选取70例患者74颗磨牙中根管中、重度弯曲且下段钙化堵塞的根管139个．采用K锉结合EDTA制剂分次疏通弯曲钙化根管．机动镍钛根管器械扩大并行冷牙胶侧压根管充填。结果实验组136根管中有114根管疏通成功并完成根管治疗。弯曲钙化根管疏通成功率为83．8％，无根管偏移、台阶形成、根管壁侧穿及器械折断发生。对照组139根管中有70根管疏通成功并完成根管治疗．弯曲钙化根管疏通成功率为50．4％，8个根管发生根管偏移及台阶形成，未发生根管壁侧穿及器械分离。结论C型先锋锉与EDTA相结合．采用分次疏通技术．可作为临床上治疗磨牙弯曲钙化根管的有效方法。     

Comparison of spreader penetration during lateral compaction of .04 and .02 tapered gutta-percha

The purpose of this study was to compare the initial penetration depth of fine-fine nickel-titanium (NiTi) and fine-fine stainless-steel (SS) spreaders during lateral compaction of .02 or .04 tapered master gutta-percha cones and to evaluate the effect of increasing canal curvature on penetration depth. Fifty-one root canals were instrumented to a standardized size and grouped by degree of curvature for comparison. Our results showed that NiTi spreaders penetrated to a significantly greater depth than SS spreaders using .02 tapered gutta-percha in canal curvatures greater than 20 degrees and when using .04 tapered gutta-percha regardless of canal curvature. No significant difference occurred between NiTi and SS-spreader penetration using .02 tapered gutta-percha in canal curvatures of 0 to 20 degrees (p > 0.05). Both NiTi and SS spreaders penetrated to a greater depth as canal curvatures increased to greater than 20 degrees (p < 0.05). Both NiTi and SS spreaders penetrated to a shallower depth with .04 tapered gutta-percha compared with .02 tapered gutta-percha (p < 0.0001).     

Comparison of nickel-titanium and stainless-steel spreader penetration and accessory cone fit in curved canals

The purpose of this study was to compare nickel-titanium and stainless-steel spreader penetration in curved canals. Twenty prepared plastic blocks with a 30 degrees curvature were used for each part of the study. In part 1, the force required to insert each spreader to within 1 mm of working length in an empty canal was measured. In part 2, the force required to insert each spreader to within 3 mm of working length was measured in a canal containing a master cone. In part 3, the depth of penetration of each spreader with a master cone in place using a 1.5 kg force was measured. Additionally, in part 3, the depth of penetration of the first accessory cone was measured. The results from part 1 showed that a nickel-titanium spreader required significantly less force than a stainless-steel spreader (0.30 kg vs. 0.59 kg). In part 2, a nickel-titanium spreader required significantly less force than a stainless-steel spreader (1.56 kg vs. 2.42 kg). In part 3, a nickel-titanium spreader penetrated significantly deeper than a stainless-steel spreader (15.0 mm vs. 14.0 mm). There was no significant difference in the depth of penetration of the first accessory cone used after either spreader (0.8 mm vs. 0.7 mm). Therefore, the potential for vertical root fracture in curved canals during lateral condensation may be minimized by using nickel-titanium spreaders.     

Comparison of some physical properties of finger spreaders made of stainless steel or nickel-titanium alloys

The purpose of this study was to evaluate the flexibility, shape, and surface finishing of stainless steel (SS) and nickel-titanium (NiTi) finger spreaders as well as to compare the load required to insert these spreaders along a gutta-percha point adapted to the apical segment of curved or straight artificial canals. Instrument flexibility was investigated by using a universal testing machine in the cantilever-flexibility test. Scanning electron microscopy (SEM) was used to examine the shape and surface finishing of different sizes of SS and NiTi finger spreaders. Penetration load was evaluated only for spreaders size C by using the universal testing machine in a compressive test. As for flexibility, the load needed to bend the SS finger spreader sizes A, B, C, and D was approximately 167%, 146%, 102%, and 64% greater than the respective sizes of NiTi finger spreaders. SEM analysis revealed that the instrument tips were always tapered, but with different vertices. NiTi spreaders showed tips with circumferential grooves; whereas, those from SS spreaders exhibited longitudinal grooves. NiTi finger spreaders required a significantly higher penetration load than SS spreaders. This difference was probably related to the different shapes and surface finishing of the instrument tips. Different characteristics of finger spreaders may result in different clinical performance during the lateral compaction technique.     

The percentage of gutta-percha-filled area in simulated curved canals when filled using Endo Twinn, a new heat device source

AIM: To compare the percentage of gutta-percha-filled area (PGP) in simulated root canals when varying the penetration depth and function of the pluggers (heat versus heat plus vibration) using Endo Twinn. METHODOLOGY: Sixty-four resin blocks with simulated 34-35 degrees curved canals were randomly divided into two groups in order to obtain two canal shapes: group A with 0.8 taper and group B with 0.4 taper. The apical portion of each canal was prepared to a size 20 K-file. The canals were filled with gutta-percha in combination with a root canal sealer. In each group 16 canals were filled using the Endo Twinn heat function and 16 canals by means of both the heat and the vibration function. All samples were sectioned horizontally at three levels (1.25, 2.5 and 4.0 mm from the working length) and the PGP was measured. Data were analysed using ANOVA test. RESULTS: At the 1.25 mm level PGP was significantly greater using the vibration function (P = 0.0329) and in 0.8 taper canals (P < 0.0001). At the 2.5 mm level the PGP was greater in the canals with 0.8 taper compared with a 0.4 taper with or without vibration (vibration, P = 0.0056; interaction taper-vibration, P = 0.0020). In 0.4 taper canals the PGP was greater when the vibration function was activated. At the 4 mm level in 0.8 taper canals there was no significant difference in PGP with or without the vibration (P = 0.6742). CONCLUSIONS: 0.8 taper canals had significantly greater PGP than 0.4 taper canals. At the 1.25 mm level there was significantly greater PGP when the vibration function was activated.     

A comparison of spreader penetration depth and load required during lateral condensation in teeth prepared using various root canal preparation techniques

AIM: To compare the influence of various root canal preparation techniques on spreader penetration depth and load required during lateral condensation with gutta-percha and sealer. METHODOLOGY: Eighty extracted human teeth with single and straight canals were used. Twenty teeth were instrumented using one of four root canal preparation techniques. The four preparation techniques were: step-back technique without Gates-Glidden drills, step-back technique with Gates-Glidden drills, crown-down pressureless technique and hybrid technique (step-down/step-back). After root canal preparation had been completed a simulated periodontal ligament was fabricated from a uniform layer of silicone impression material. The roots were then mounted in an acrylic resin to simulate the physical condition found in tooth socket. A standardized stainless steel hand spreader of the same size as the master apical file was mounted in an Instron testing machine and lateral compaction with gutta-percha and sealer was performed. The load value was recorded from the Instron testing machine. The spreader penetration depths were measured with an endodontic ruler. The data obtained were analysed statistically using anova and Student's t-tests. RESULTS: No significant difference in initial spreader load needed to condense the master cone was found amongst the four canal preparation techniques (P > 0.05). The step-back technique with Gates-Glidden drills and the hybrid technique demonstrated the least difference between the initial spreader penetration and the working length (mean 1.925 and 2.25 mm, respectively). The step-back technique without Gates-Glidden drills and the crown-down pressureless technique had the greatest difference between initial spreader penetration and the working length (mean 4.425 and 4.75 mm, respectively). CONCLUSION: The flare created by canal preparation affected spreader penetration depth, but had no effect on the spreader load.     

Effect of different temperatures and penetration depths of a System B plugger in the filling of artificially created oval canals

OBJECTIVES: The purpose of this study was to compare the gutta-percha-filled area in oval canals while varying the temperature and penetration depth of the System B plugger. STUDY DESIGN: Seventy-five resin blocks, with artificially created oval canals, were obturated by using a continuous wave technique. In groups 1, 2, and 3, the plugger was introduced to a depth of 4 mm from the apex at set temperatures of 100, 200, and 350 degrees C, respectively. In group 4, the plugger was inserted to a depth of 2 mm from the apex at a set temperature of 200 degrees C. Group 5 was obturated in the same way as group 2, and then an additional cold plugging was performed to a depth of 3 mm from the apex. The cross sections of the obturated canals were photographed, and the percentage of the gutta-percha-filled area (PGP) was measured. RESULTS: No significant differences were found between the 3 different temperature settings (P >.05). At 1 mm from the apex, group 4 showed the highest PGP (95.57% +/- 6.86), followed by group 5 (84.72% +/- 12.19), and group 2 (67.33 +/- 13.03) (P <.05). CONCLUSION: In artificially created oval canals, plugger temperature within the range used in this study did not affect the PGP. However, the penetration depth of the plugger was significantly related to PGP.     

A comparison of instrument-centering ability within the root canal for three contemporary instrumentation techniques

AIM: To study and compare Great Taper (GT) hand files using a reversed balanced force technique, nickel-titanium (NiTi)flex files with a balanced force technique and stainless steel (SS) K-type files using a step-back technique. METHODOLOGY: Forty-eight extracted mandibular premolar teeth with single root canals having curvatures between 15 and 45 degrees were prepared using a modified Bramante model and randomly divided into three groups. The teeth were cross-sectioned at 2, 6 and 10 mm from the working length. Preoperative images of canals at three levels were captured at 20x magnification using a stereomicroscope. Canals in each group were, respectively, prepared to an apical size.10 GT file with 0.2 mm tip diameter, size 30 NiTiflex file and size 30 SS K-file. The GT file was used in a reversed balanced force technique, the NiTiflex file was used in a balanced force technique, and the SS K-file was used in a step-back technique. Postoperative canals were imaged under the conditions same as those for the preoperative canals. The postoperative images were superimposed over the preoperative images using software photoshop 6.0. The ability to maintain the instrument in the central axis of the canal and the deviation from the central canal axis were determined and compared by statistical analysis, along with the assessment of the amount of dentine removed. RESULTS: At apical level, the centering ratio, the distance of transportation and the dentine removed in GT and NiTiflex groups were significantly less than those in SS group (P < 0.01), but no statistical differences were found between the two NiTi groups. At other levels, there were no substantial differences amongst the groups. CONCLUSIONS: Compared with SS K-files, GT hand files and NiTiflex files remain better centered and produce significantly less transportation in curved canals.     

ProFile ProTaper镍钛根管器械与不锈钢K锉预备弯曲根管的比较研究

目的：比较ProFile镍钛机用根管器械，ProTaper镍钛手用根管器械和不锈钢K锉用于弯曲根管预备时的根管拉直和根尖偏移，为ProFile和ProTaper的临床应用提供实验依据。方法：将正畸前减数拔除的30个下颌第一前磨牙随机分为3组，分别用不锈钢K锉、ProTaper镍钛手用根管器械、ProFile镍钛机用根管器械做根管预备，分析评价其根管拉直和根尖偏移情况。结果：不锈钢K锉组的根管拉直、根尖偏移显著大于ProTaper和ProFile预备组。结论：ProFile和ProTaper镍钛根管预备器械与传统的不锈钢器械相比更适合弯曲根管的根管预备。     

Shaping ability of ProFile and K3 rotary Ni-Ti instruments when used in a variable tip sequence in simulated curved root canals

AIM: To compare the shaping ability of ProFile and K3 rotary Ni-Ti instruments when used in a variable tip sequence in simulated curved root canals with different curvature and radius. METHODOLOGY: ProFile or K3.06 taper instruments were used to prepare simulated canals of 20 degrees curvature and 5 mm radius (n = 10) and 30 degrees curvature and 3 mm radius canals (n = 10) in resin blocks. All canals were prepared to an apical size 40 at 0.5 mm from the canal terminus using a variable tip crown-down sequence. Pre- and postinstrumentation digital images were recorded, and an assessment of the canal shape was determined using a computer image analysis program. The material removal from the inner and outer wall of the canal was measured at 28 measuring points, beginning 0.5 mm from the end-point of the canal and the data compared using the Mann-Whitney U-test. RESULTS: In 20 degrees and 30 degrees canals both instruments significantly removed more (P < 0.05) material on the outer wall than the inner wall in the apical half of the canal. For ProFile files there was no significant difference in the amount of material removed on the outer canal wall between the 20 degrees and 30 degrees canals. However, in the K3 groups significantly more (P < 0.05) outer canal wall was removed in the apical area in 20 degrees canals. When comparing both instruments the results showed that in 20 degrees canals K3 instruments removed more outer and inner canal wall than ProFile instruments (P < 0.05) but that there was no significant difference (P > 0.05) between the instruments in 30 degrees canals. CONCLUSION: Within the limitation of this study, both rotary nickel-titanium instruments prepared a well-shaped root canal with minimal canal transportation.     

Efficacy of various concentrations of NaOCl and instrumentation techniques in reducing Enterococcus faecalis within root canals and dentinal tubules

AIM: To evaluate the efficacy of 0.5%, 2.5% and 5.25% sodium hypochlorite (NaOCl) as intracanal irrigants associated with hand and rotary instrumentation techniques against Enterococcus faecalis within root canals and dentinal tubules. METHODOLOGY: A total of 180 extracted human premolar teeth were infected for 21 days with E. faecalis. The specimens were divided into 12 groups, as follows: group 1: 5.25% NaOCl + Hybrid technique (Valdrighi et al. 1998); group 2: 5.25% NaOCl + nickel-titanium (NiTi) rotary technique 4 mm shorter than the apex (by FOP-UNICAMP); group 3: 5, 25% NaOCl + NiTi rotary technique (Hero 642); group 4: 2.5% NaOCl +Hybrid technique; group 5: 2.5% NaOCl + NiTi rotary technique 4 mm shorter than the apex; group 6: 2.5% NaOCl + NiTi rotary technique (Hero 642); group 7: 0.5% NaOCl + Hybrid technique; group 8: 0.5% NaOCl + NiTi rotary technique 4 mm shorter than the apex; group 9: 0.5% NaOCl + NiTi rotary technique (Hero 642); group 10: sterile saline solution + Hybrid technique; group 11: sterile saline solution + NiTi rotary technique 4 mm shorter than the apex; group 12: sterile saline solution + NiTi rotary technique (Hero 642). Canals were sampled before and after preparation. After serial dilution, samples were plated onto brain heart infusion (BHI) agar, and the colony forming units (CFU) that were grown were counted. The teeth were sectioned into three thirds and dentine chips were removed from the canals with conical burs. The samples obtained with each bur were immediately collected into test tubes containing BHI broth, and were incubated at 37 degrees C and plated onto BHI agar. The CFU were counted and analysed. RESULTS: At all depths and thirds of the root canals and for all techniques used, 5.25% NaOCl was shown to be the most effective irrigant solution tested when dentinal tubules were analysed, followed by 2.5% NaOCl. No differences among concentrations in cleaning the canals were found. CONCLUSIONS: Especially at higher concentrations, NaOCl, was able to disinfect the dentinal tubules, independent of the canal preparation technique used.