The adaptation of mechanically softened gutta-percha to the canal walls in the presence or absence of smear layer: a scanning electron microscopic study

The objective of this study was to compare the adaptation of mechanically softened gutta-percha to the root canal wall in the presence and absence of smear layer. The root canals of 20 freshly extracted human maxillary incisors were cleaned and shaped. Prior to obturation, 10 root canals were irrigated with 20 ml of 50% citric acid followed by 20 ml of 5.25% sodium hypochlorite. All canals were obturated with mechanical compaction of gutta-percha and AH-26 sealer. After 72h, each tooth was fractured in half. Scanning electron microscopy demonstrated that the sealer had formed a continuous layer in contact with the canal walls, becoming progressively thinner towards the apex. The sealer pentrated into the dentinal tubules along with projections of gutta-percha only in those teeth without smear layer.     

An apical leakage study in the presence and absence of the smear layer

The apical seal produced by low-temperature injection of gutta-percha, with or without root canal sealer, in the presence or absence of the smear layer was evaluated quantitatively using an electrochemical technique. The root canals of 44 teeth were prepared with the smear layer intact following a final flush of NaOCl (group 1), while the root canals of a further 44 teeth were prepared and the smear layer removed with a final flush with EDTA followed by NaOCl (group 2). Subgroups were obturated using Ultrafil System alone or accompanied by Calciobiotic Root Canal Sealer. Microleakage data was expressed as a percentage of apical leakage evident in each group. Statistical analysis of the results revealed that the groups obturated with Ultrafil alone showed no significant differences in leakage compared with the groups where sealer was used, either when the smear layer had been left intact or removed. (P>0.05). However, comparison of the combined two groups with smear layer present versus the combined two groups with smear layer removed showed a highly significant difference (P<0.01), with the incidence of leakage reduced in the absence of the smear layer.     

An in vitro study of the quality of root fillings in teeth obturated by lateral condensation of gutta-percha or Thermafil obturators

The aim of this in vitro study was to assess the quality of root canal obturation and degree of linear apical dye penetration in teeth root filled with either laterally condensed gutta-percha or Thermafil obturators, A total of 150 teeth with single roots were included in the study. All canals were prepared using a standard step-back technique with anticurvature filing. Radiographs taken of the teeth to show the maximum degree of canal curvature were then exposed and the angle, radius and position of curvature determined. This information about the canals, together with their working length and diameter at end-point, was used to divide the teeth into two experimental and two control groups. A total of eight teeth were excluded because of technical difficulties, 65 were filled with Thermafil obturators, 63 were filled with laterally condensed gutta-percha whilst 14 teeth remained unfilled and acted as controls. Following obturation, the teeth were radiographed in two planes and the technical quality of fill assessed on a four-point scale. All access cavities were then sealed and the teeth immersed in dye for 48 h before being split longitudinally. Linear dye penetration via the apical foramen was then assessed. Canal obturation with Thermafil obturators (0.7 min) was significantly quicker (P > 0.001) than lateral condensation (6.4 min). Apical extrusion of sealer and gutta-percha occurred significantly more often with Thermafil obturators but there was little difference in the technical quality of the fillings and no significant difference in dye penetration. Under the conditions of this study, Thermafil obturators proved a satisfactory alternative to lateral condensation of gutta-percha.     

根尖止点阻止根充材料超充的效果研究

目的:研究根管治疗中制备根尖止点对阻止根管充填材料超充的影响。方法:选取80个单根管上、下颌尖牙,其中40个牙采用逐步后退技术,常规制备根尖止点进行根管预备至根尖孔上1mm,另40个牙亦采用逐步后退技术预备至根尖孔,不进行根尖止点的制备;再将以上各组牙随机平分为两组,分别采用冷牙胶侧方加压和热牙胶垂直加压方法充填根管,观察并记录每组中牙胶超出根尖的牙数,收集每个牙超出的充填材料(牙胶和糊剂)并称量,对实验结果进行统计学分析。结果:制备根尖止点的侧方加压组与不制备根尖止点的侧方加压组之间根充材料超出的量、制备根尖止点的垂直加压组与不制备根尖止点的垂直加压组之间根充材料超出的量均无统计学差异(P>0.05)。结论:通过在初尖锉的基础上扩大3#的方法制备根尖止点并不一定能起到减少根充材料超充的作用。     

Comparison of cold lateral condensation and a warm multiphase gutta-percha technique for obturating curved root canals

AIM: The aim of this project was to evaluate and compare the radiographic quality and sealability of root fillings in extracted human teeth using lateral condensation of gutta-percha or multiphase gutta-percha obturation (Alphaseal). METHODOLOGY: A total of 108 freshly extracted human, mature single-rooted teeth were divided into two identical groups of 54 teeth on the basis of root canal shape. The canals were prepared to a minimum 0.055 taper and enlarged to size 35 at the apex. All root canals were flushed with 17% EDTA solution and 2.5% NaOCl to remove the dentinal smear layer. The canals of one group were obturated using cold lateral condensation of gutta-percha and the canals of the other group were filled using a warm multiphase gutta-percha obturation technique. The extrusion of sealer and/or gutta-percha through the apex of the teeth was recorded using a simple yes/no scheme. The sealability of each technique was assessed by a dye penetration method. The radiographic quality of obturation was determined for each canal using a four-point scale. RESULTS: Root canals filled by multiphase obturation had significantly more extrusion of sealer (P < 0.001) and gutta-percha (P < 0.001) than canals filled by lateral condensation. Canals filled by multiphase gutta-percha obturation had significantly less apical dye leakage than those obturated by lateral condensation (P < 0.05). Lateral condensation achieved significantly better scores for radiographic quality than multiphase obturation from the bucco-lingual view (P < 0.01). CONCLUSIONS: Under laboratory conditions multiphase gutta-percha had better sealability but poorer radiographic quality than lateral condensation.     

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目的对比评价三种根管充填技术的根尖封闭能力。方法收集2011年10月至2012年5月中国医科大学附属口腔医院口腔颌面外科门诊因正畸或牙周病拔除的新鲜离体单根管牙34颗,根管清理后用机用ProTaDer镍钛锉经Crown—Down技术预备,然后随机分为A、B、C三组。A组（11颗）采用冷牙胶侧方加压充填技术充填根管,B组（10颗）采用超声侧方加压充填技术充填根管,c组（13颗）采用连续波热牙胶垂直充填技术充填根管。所有实验牙均使用AHPlus根充糊剂。根管充填后的各组实验牙采用染料渗透法检测根尖微渗漏的发生情况,体式显微镜下测量自根尖孔向冠方的染料渗透长度,采用SPSS11．5统计软件包对测量数据进行分析。结果A组与B、c组的根尖微渗漏数值间差异有统计学意义（P〈0．05）,B组与c组的根尖微渗漏数值间差异无统计学意义（P〉0．05）。结论超声侧方加压充填技术和连续波热牙胶垂直充填技术的根管封闭能力优于冷牙胶侧方加压技术,而前两种充填技术的根管封闭能力无明显差别。     

The sealing ability of an epoxy resin root canal sealer used with five gutta-percha obturation techniques

Abstract – The purpose of the present study was to evaluate the apical sealing ability of an epoxy resin root canal sealer (AH-26) when used with different gutta-percha obturation techniques (i.e. cold lateral condensation, warm vertical condensation, hybrid condensation) and with Thermafil and Soft-Core obturators. Straight single-rooted teeth with mature apices were prepared according to the crown-down/step-back technique and divided in five groups of 45 teeth and one group of 12 control teeth. After root canal filling 15 teeth of each group were kept for 1 day, another 15 teeth for 1 week, and another 15 teeth for 4 months at 37 °C in vacutainers in 80% relative humidity. The 237 teeth were immersed in india ink for 90 hours, each root was split and sectioned longitudinally, and the maximum extent of leakage was measured using a stereomicroscope at ×6 magnification. It became clear that leakage occurred whatever technique was combined with AH26 and that leakage increased with time. The amount of apical leakage and the number of leaking teeth in the Soft-Core obturator groups was significantly higher than all other 4 gutta-percha obturation techniques combined with AH26. In this respect, the hybrid gutta-percha condensation technique turned out to be superior to the four other condensation techniques.     

Bacterial penetration along different root canal filling materials in the presence or absence of smear layer

AIM: To study the effect of the smear layer on the penetration of bacteria along different root canal filling materials and to examine the dentine/sealer and sealer/core material interfaces for the presence of bacteria. METHODOLOGY: A total of 110 human root segments were instrumented to size 80 under irrigation with 1% sodium hypochlorite. Half of the roots were irrigated with a 5-mL rinse of 17% EDTA. Roots with and without smear layer were filled with gutta-percha (GP) and AH Plus sealer (AH), GP and Apexit sealer (AP), or RealSeal cones and sealer (RS). Following storage in humid conditions at 37 degrees C for 7 days, the specimens were mounted into a bacterial leakage test model for 135 days. Survival analyses were performed to calculate the median time of leakage and log-rank test was used for pairwise comparisons of groups. The level of significance was set at P = 0.05. Selected specimens were longitudinally sectioned and inspected by scanning electron microscopy for the presence of bacteria at the interfaces. RESULTS: In the presence of the smear layer, RS and AP leaked significantly more slowly than in its absence. In the absence of the smear layer, AH leaked significantly more slowly than RS. SEM results indicated a differential pattern of bacterial penetration among the sealers. CONCLUSIONS: Removal of the smear layer did not impair bacterial penetration along root canal fillings. A comparison of the sealers revealed no difference except that AH performed better than RS in the absence of the smear layer.     

Endodontic leakage studies reconsidered. Part II. Statistical aspects

The aim of many endodontic studies is to compare two or more treatment methods, techniques or materials, for example, to detect differences in mean leakage scores. As it is not feasible to study large populations, samples are taken. The important question then arises as to how large the sample sizes have to be in order to establish the‘true’(= populations') mean scores. First, it must be determined which magnitude of the difference (= v) between the mean scores is of endodontic interest. Based upon v and a few related statistical parameters, one may calculate how large the samples must be in order that a statistical test yields a significant result for a difference that is of endodontic importance. In other words, the‘power’of a test, depending on the sample size among other factors, must be large enough to detect the‘true’a priori determined difference between the populations. The use of small sample sizes may imply that a rather large difference between two mean leakage scores is not found to be significant, thereby leading to incorrect conclusions. This article describes the power and the statisti-cal related factors that determine the adequate size of samples. Examples of power calculation are presented. Next, the power of publicized endodontic leakage studies was evaluated. Almost two-thirds of the sample sizes were 10 or less, and about 90% were 20 or less. Less than one-half of the tests had an adequate power (conventionally ≤ 0.80). It is necessary to be cautious when extrapo-lating the results of such studies, because of the limited power of the statistical tests. The power may be increased by using larger sample sizes or, alternatively, by enlarging the‘effect size', by either taking an interest in a larger difference between the mean scores, or by minimizing the variability of the data.     

A laboratory study of root fillings in teeth obturated by lateral condensation of gutta-percha or Thermafil obturators

The aim of this in vitro study was to assess the quality of root canal obturation and degree of apical dye penetration in teeth root-filled with either laterally condensed cold gutta-percha or Thermafil obturators. A total of 144 extracted teeth with single roots were included in the study. All canals were prepared with a standard technique using a sonic handpiece with copious irrigation. Radiographs taken of the teeth to show the maximum degree of canal curvature were then exposed and the angle, radius and position of curvature determined. This information about the canals, together with their working length and diameter at end-point was used to divide the teeth into two experimental and two control groups. A total of 71 teeth were filled with Thermafil obturators, 69 with lateral condensation while four teeth remained unfilled and acted as controls. Following obturation, the teeth were radiographed in two planes and the technical quality of fill assessed on a four-point scale. All access cavities were then sealed and the teeth immersed in dye for 48 h before being split longitudinally. Linear dye penetration via the apical foramen was then assessed. In both straight and curved canals obturation with Thermafil obturators was significantly quicker (P< 0.001) than lateral condensation. Apical extrusion of gutta-percha occurred significantly more often in straight canals obturated with lateral condensation (P< 0.005) but there was no difference in curved canals. There was little difference in the radiographic quality of fill in the apical halves of the root fillings but Thermafil obturators were significantly better in the coronal halves when viewed from the proximal. Apical leakage of dye was significantly worse (P< 0.05) in curved canals filled with lateral condensation with a similar, but not significant, trend in straight canals. Under the conditions of this study, Thermafil obturators proved a satisfactor alternatie to lateral condensation of gutta-perch.     

Evaluation of the Trifecta obturating technique

Abstract – The aim of this project was to evaluate and compare the radiographic quality and sealability of root fillings in extracted human teeth using lateral condensation of gutta‐percha or the Trifecta obturating system. One hundred freshly extracted human mature, single‐rooted teeth were divided into four identical groups of 25 teeth on the basis of root canal shape. The root canals of two groups were prepared in such a way as to produce a relatively parallel canal shape with little or no flare towards the coronal orifice. The root canals of the other two groups were prepared in such a way as to produce a canal shape that was deliberately more flared to ensure that they were wider at the orifice than at the endpoint of the preparation. All root canals were flushed with 17% EDTA solution and 2.5% NaOCl to remove the dentinal smear layer. The canals of one flared and one parallel group were obturated using cold lateral condensation and the canals of the other two groups were obturated using the Trifecta system. The sealability of each technique was assessed by a dye penetration method. The radiographic quality of obturation was determined for each canal using a 4‐point scale. Canals filled with thermoplasticised gutta‐percha had significantly less apical dye penetration than those obturated by lateral condensation (P<0.001). Lateral condensation achieved significantly better scores for radiographic quality than thermoplasticised gutta‐percha from both the bucco‐lingual (P<0.001) and the mesio‐distal views (P<0.001). Root canals obturated using the Trifecta technique showed significantly more apical extrusion of sealer than those obturated by lateral condensation (P<0.001). Under laboratory conditions the Trifecta technique had better sealability but poorer radiographic quality than lateral condensation.     

The apical seal of root canal sealing cements using a radionuclide detection technique

The aim of this study was to evaluate the apical seal obtained with various root canal sealing cements using a new method based on the use of a radionuclide and an external detection technique. A total of 150 maxillary incisors and canines, which had been kept in saline solution, were used. The root canals were instrumented with a stepback technique and circumferential filing. Six experimental groups and two control groups were randomly formed. Each experimental group was obturated by a lateral condensation technique with gutta-percha points and a different sealing cement (two based on zinc oxide-eugenol cement, two based on resins and two on calcium hydroxide); the positive control used gutta-percha without sealing cement, while in the negative control the apex was covered with nail varnish, leaving the root canal empty. The apical leakage was measured using an external detection technique after submerging the root apices in a solution containing the radioisotope metastable 99Tc. No leakage was observed in the negative control group. There was a large difference between the leakage observed in the positive control group and the experimental groups. The best seal was obtained using Sealapex cement, which differed significantly from AH26, Tubli-Seal and Diaket; there was no significant difference between the latter. The poorest results were obtained with Endomethasone and CRCS; there was a significant difference between these and the previous three sealing cements.     

Adaptation and sealability of two contemporary obturation techniques in the absence of the dentinal smear layer

AIM: The aim of this study was to evaluate the adaptation and short- and long-term sealability of two different thermoplastic techniques--a core carrier technique, Thermafil; and a warm vertical continuous wave of compaction technique, System B. METHODOLOGY: Fifty-one mesial roots of mandibular molars with separate canals, patent canal orifices and curvature greater than 15 degrees were cleaned and shaped with Orifice Shapers and ProFile.04/.06 taper Ni-Ti rotary files using 5.25% NaOCl and 17% REDTA to a size 30.04 taper Profile at the apex to create a continuous tapered preparation. Canals were randomly obturated with Sealapex root canal sealer and either alpha-phase gutta-percha on a plastic Thermafil carrier, or nonstandardized beta-phase gutta-percha using the System B heat source. Proximal radiographs of roots were evaluated by three examiners based on established criteria for overall material adaptation, apical adaptation and filling material extrusion. Teeth were randomly separated into three groups of 17 each and placed in black India ink for 10 days, 24 h, or after 67 days storage in Hank's Balanced Salt Solution. All roots were demineralized and rendered transparent. Three examiners evaluated the apical leakage by the linear measurement of dye penetration under the stereo-microscope. The movement of filling material into canal irregularities was also evaluated. RESULTS: Both obturation techniques were not significantly different in the overall canal obturation and in the apical third adaptation (P > 0.05). Significantly more filling material extrusion beyond the apex was noted with the Thermafil technique (P < 0.001). No significant difference was found amongst the 67-day, 10-day and 24 h System B groups (P > 0.05). The 67-day Thermafil group showed significantly more leakage than the 10-day and 24 h Thermafil groups. There was a significant difference in the degree of leakage between the 67-day Thermafil group and the 67-day System B group (P < 0.05), but not between the 10-day and 24 h groups (P > 0.05). Both obturation techniques produced substantial filling material movement into canal irregularities. CONCLUSIONS: It was concluded that Thermafil demonstrated more filling material extrusion beyond the apex and significantly more long-term apical leakage.     

Sealing capacity in vitro of thermoplasticized gutta-percha with a solid core endodontic filling technique

Abstract— This study assessed the sealing capacity of two endodontic gutta-percha filling techniques. Thirty-four single-rooted fully developed teeth were endodontically accessed, instrumented and randomly divided into two experimental groups ( n =12) and two control groups ( n =5). In Group A, root canals were obturated using a solid core thermoplastic technique (Densfil), in Group B and Group C (negative control) canals were obturated with laterally condensed gutta-percha, and in Group D (positive control) canals were left un-obturated. AH-26 was used as the sealer. Two days later, the teeth were conventionally prepared for testing apical and coronal leakage, immersed in india ink for 5 days and subsequently cleared. The linear coronal and apical extent of dye penetration was measured under a light dissecting microscope. The mean apical leakage for Group A was 1.39 mm, and for Group B 2.76 mm, whereas the mean coronal leakage for Group A was 2.87 mm, and for Group B 4.03 mm. The differences between the groups were not statistically significant (P>0.05).     

Sealing ability of thermoplasticized gutta-percha in root canal obturation using a sectional vs. a single-phase technique

Abstract Properly prepared straight root canals of freshly extracted maxillary canines and central incisors were used to evaluate the sealing ability of the sectional thermoplasticized gutta-percha obturation technique, with or without sealer and the single-phase thermoplasticized gutta-percha filling technique. The teeth were divided into 3 groups (A, B, C) of 20 teeth and were obturated using the 3 thermoplasticized gutta-percha techniques. Group A: single phase with sealer; group B: sectional technique without sealer; and group C: sectional technique with sealer. The obturated teeth were immersed in India ink for 3 days followed by clearing procedures. The teeth were then examined under a stereo microscope and the linear leakage was recorded. Statistical unpaired Student's t-tests showed significantly less dye penetration in teeth obturated using the sectional technique with sealer (group C) than in teeth obturated with the single-phase technique with sealer (group A) or the sectional technique without sealer (group B).     

不同锥度牙胶尖冷侧压充填根尖封闭性能的比较研究

目的：对比研究0.02锥度和0.06锥度牙胶尖冷侧压充填后根尖封闭效果.方法：收集离体单根管前牙53颗,经根管清理、机用ProTaper预备成型后随机分为2个实验组和1个阳性对照组,实验组每组26个样本,对照组1个样本.实验组分别用0.02锥度牙胶尖和0.06锥度牙胶尖作主尖冷侧方加压进行充填,阳性对照组不进行充填.用透明标本法配合染料渗透技术测量根尖染料的线性渗透长度,评价各组标本的根尖封闭效果.结果：阳性对照组标本染料全部进入根管.0.02锥度组染料渗透长度（0.761 ±0.457） mm,0.06锥度组（0.906±0.490） mm,差异无统计学意义（P＞0.05）.结论：机用ProTaper预备根管后,冷牙胶侧方加压充填时0.06锥度牙胶尖和0.02锥度牙胶尖的根尖封闭效果差异无统计学意义.     

Assessment of apical and coronal root canal seals using contemporary endodontic obturation and restorative materials and techniques

AIM: The purpose of this study was to evaluate the sealing ability of two contemporary endodontic obturation and restorative techniques and materials. METHODOLOGY: Seventy-nine extracted human single-rooted teeth were distributed randomly in two experimental groups of 36 and 37 specimens (groups 1 and 2, respectively), one group of three positive controls and one of three negative controls. The teeth were radiographed preoperatively, accessed, and instrumented. After smear layer removal, the teeth in group 1 were obturated using the System B and Obtura and were restored coronally with Core Paste using Tenure as a bonding agent. The teeth in group 2 were obturated using the Microseal technique and were restored coronally with amalgam using Panavia 21 as a bonding agent. All teeth in groups 1 and 2 were coated with three layers of nail varnish on all of their surfaces apart from the apical 4.0 mm and the coronal area above the cemento-enamel junction. The positive control teeth were obturated, restored coronally and completely coated with varnish, whereas the negative control teeth were not obturated, restored coronally, nor coated with varnish. The teeth were radiographed postoperatively and retained in saline solution for 10 days. For the next 10 days they were submerged in India ink. Subsequently all teeth were demineralized, dehydrated and rendered transparent. Dye penetration was measured using a stereomicroscope. RESULTS: All materials and techniques provided minimal to zero dye penetration, apart from one specimen in the Core Paste group that showed 4.0 mm of dye penetration. The Wilcoxon rank sum test and t-test showed no statistically significant differences and all materials and techniques tested presented with a high degree of acceptability. CONCLUSIONS: It was concluded that these contemporary techniques and materials provide equally good results, but long-term studies are needed for outright inferences to be drawn relative to their clinical performance.     

Effect of dowel space preparation on the apical seal of root canal fillings

Abstract The effect of post preparation on the apical seal was studied using simulated root canals. The maximum level of removal was tested with residual fillings 1, 2, 3, and 4 mm long. All of the artificial canals were filled with gutta-percha, Grossman's sealer, and lateral condensation. The removal was immediate and carried out with warm pluggers and the dowel space was completed with a Peeso drill. Stainless steel posts were cemented with zinc phosphate cement in the free space of the root canals. The coronal access of the canals was sealed with temporary fillings. After setting the materials, the specimens were immersed in a 2% methylene blue dye solution for 72 h and were observed with a measuring microscope. The final length of the apical fillings was found to be different from the intended length in every group. As far as leakage was concerned, 1, 2, and 3 mm-long fillings did not show a significant difference when compared with the negative control group (that is to say, filled canals where no dowel space was created). In the 4 mm fillings the leakage value was zero. These findings may be of clinical importance when restoring short roots.     

Push‐out bond strength of gutta‐percha with a new bioceramic sealer in the presence or absence of smear layer

The purpose of this study was to compare the bond strength of a new bioceramic sealer (EndoSequence BC Sealer) and AH Plus in the presence or absence of smear layer. Extracted single‐rooted human teeth were prepared and randomly divided into four groups. In groups 1 and 3, the root canals were finally irrigated with 5.25% NaOCl and smear layer was not removed, but in groups 2 and 4, the root canals were finally irrigated with 17% EDTA followed by 5.25% NaOCl in order to remove the smear layer. In groups 1 and 2, the root canals were obturated with gutta‐percha/AH Plus, but in groups 3 and 4, obturation was performed with gutta‐percha/EndoSequence BC Sealer. Push‐out bond strength and failure modes were evaluated. The bond strength of gutta‐percha/AH Plus and gutta‐percha/EndoSequence BC Sealer was not significantly different (P = 0.89). The presence or absence of smear layer did not significantly affect the bond strength of filling materials (P = 0.69). The mode of bond failure was mainly cohesive for all groups. In conclusion, the bond strength of the new bioceramic sealer was equal to that of AH Plus with or without the smear layer.     

Obturation of root canals with different sealers using non-instrumentation technology

AIM: To evaluate and compare the sealing quality of hand- or vacuum-obturated root canals after hand preparation or hydrodynamic cleansing of root canals, respectively. METHODOLOGY: After assessing root curvature, 96 single-rooted deep-frozen teeth were divided into eight comparable groups. The root canals of four groups were instrumented with the balanced force technique. The remaining uninstrumented teeth were connected to a reduced-pressure device (NIT) and the root-canal system perfused with 2.5% NaOCl under alternating pressure fields. This dissolved the pulpal tissues and removed debris from the root-canal system. The canals of the hand-instrumented groups were obturated using the cold lateral condensation method with guttapercha and one of four different sealers (AH26, AH Plus, Apexit and Pulp Canal Sealer EWT). The teeth treated with the alternating pressure device (NIT) were obturated by a vacuum obturation method (NIT) with the same four sealers. The quality of the coronal seal was assessed using a dye penetration method. In order to minimize errors the roots were perfused with water before exposure to the dye, under vacuum. The teeth were then rendered transparent and the depth of penetration of the dye between the wall of the canal and the obturating material was measured with a stereomicroscope. RESULTS: The canals cleaned and filled by NIT showed statistically significantly less dye penetration than those obturated by lateral condensation (P < 0.05). Within the NIT group, Pulp Canal Sealer EWT exhibited significantly more dye penetration than Apexit. Amongst the control lateral condensation groups no significant differences were found between the various sealers. CONCLUSIONS: The present investigation demonstrated the validity of the NIT obturation method in combination with commonly used root-canal sealers.