Debris Remaining in the Apical Third of Root Canals after Chemomechanical Preparation by Using Sodium Hypochlorite and Glyde: An In Vivo Study

Introduction

During chemomechanical instrumentation, several liquid or paste substances are used to ease the action of the files and to eliminate debris and the smear layer. The aim of this study was to evaluate whether the use of a paste containing EDTA during cleaning and shaping of the root canal helps to eliminate debris.

Methods

Twenty root canals in dog teeth were instrumented by a crown-down technique by using nickel-titanium rotary files. In 10 root canals (group A), sodium hypochlorite was used during instrumentation, followed by a final irrigation with 17% liquid EDTA. In another 10 canals (group B), sodium hypochlorite was again used as the irrigating solution, but Glyde File Prep paste was used with every instrument, and a final irrigation with EDTA was also carried out. Two additional teeth were used as positive and 2 as negative controls. The jaws were prepared for histologic evaluation.

Results

In group A where Glyde was not used during cleaning and shaping, little or no debris was found in the apical third of the instrumented root canals; however; in group B in which Glyde File Prep paste was used during chemomechanical instrumentation, moderate to high accumulation of debris was observed in the apical third.

Conclusions

The use of Glyde File Prep paste during rotary mechanical instrumentation favors the accumulation of debris in the apical third of the root canals. Irrigation with NaOCl and a final flush with EDTA by means of a small-gauge needle with simultaneous aspiration led to less accumulation of debris than in the Glyde File Prep group (P < .05).     

Effect of F-File on removal of the smear layer: a scanning electron microscope study

The aim of this study was to evaluate the effectiveness of F-File with NaOCl on removal of the smear layer. A total of 48 single-rooted teeth were instrumented using crown-down technique with one of the irrigation agents: distilled water, 5.25% NaOCl, RC-Prep, Glyde, MTAD or F-File with NaOCl. The remaining smear layer was scored at cervical, middle and apical thirds of the roots with SEM. In all the canals of experimental groups the coronal sections were cleaner than the middle and apical sections except with distilled water (P<0.001). In the coronal third, intensive smear layer was observed in distilled water, NaOCl and F-File groups and less smear layer in MTAD (P<0.05) and least in RC-Prep and Glyde groups. In the middle third, RC-Prep and Glyde groups had less smear layer than the other groups (P<0.001). In the apical third, there was intensive smear layer in all specimens and statistical analyses showed no significant difference among the groups (P>0.05). The F-file failed to improve the effect of NaOCl in removing smear layer.     

Removal of the smear layer from flattened canals using different chemical substances

This study used scanning electron microscopy to evaluate the flattened root canals of human mandibular incisors cleaned with nickel-titanium instruments and different chemical substances. Teeth were selected and divided randomly into five groups (n = 10) according to the chemical substances used in the biomechanical preparation: 5.25% sodium hypochlorite (Group 1), 5.25% sodium hypochlorite plus a final irrigation with 17% EDTAC (Group 2), EDTA gel combined with 5.25% sodium hypochlorite (Group 3), 2% chlorhexidine gel (Group 4), and 5.25% sodium hypochlorite combined with Glyde File Prep gel (Group 5). Data analysis showed a statistically significant difference (p < 0.001) among groups. Groups 1 and 5 were similar statistically (p > 0.001) and displayed a higher amount of smear layer on canal walls. Samples from Groups 2, 3, and 4 revealed root canal walls without smear layer and exposed dentin tubules. Among the associations tested in this study, 5.25% sodium hypochlorite solution combined with 17% EDTAC, 5.25% sodium hypochlorite combined with EDTA gel, and 2% chlorhexidine gel all were effective substances for removing the smear layer from flattened root canals.     

Reducing surface tension in endodontic chelator solutions has no effect on their ability to remove calcium from instrumented root canals

The aim of this study was to evaluate the effect of reducing surface tension in endodontic chelator solutions on their ability to remove calcium from instrumented root canals. Aqueous solutions containing 15.5% EDTA, 10% citric acid, or 18% 1- hydroxyethylidene-1, 1-bisphosphonate (HEBP) were prepared with and without 1% (wt/wt) polysorbate (Tween) 80 and 9% propylene glycol. Surface tension in these solutions was measured using the Wilhelmy method. Sixty-four extracted, single-rooted human teeth of similar length were instrumented and irrigated with a 1% sodium hypochlorite solution and then randomly assigned (n = 8 per group) to receive a final one-minute rinse with 5 ml of test solutions, water, or the pure aqueous Tween/propylene glycol solution. Calcium concentration in eluates was measured using atomic absorption spectrometry. Incorporation of wetting agents resulted in a reduction of surface tension values by approximately 50% in all tested solutions. However, none of the solutions with reduced surface tension chelated more calcium from canals than their pure counterparts (p > 0.05).     

Effect of irrigation solutions on the filling of lateral root canals

Abstract An in vitro study involving 66 single–rooted human teeth was performed. The teeth were divided into 3 groups: control group, root canals instrumented and irrigated with distilled water; experimental group A, root canals instrumented and irrigated with 15% EDTA; and experimental group B, root canals instrumented and irrigated with 5% sodium hypochlorite. All canals were filled with laterally condensed gutta-percha and Diaket® A. Radiographs were taken mesiodistally and buccolingually and the number of lateral canals filled in the various teeth was counted. The group treated with 15% EDTA showed a significantly larger number of filled lateral canals than the groups irrigated with distilled water or sodium hypochlorite.     

Scanning electron microscopic study of the cleaning ability of chlorhexidine as a root-canal irrigant

AIM: To evaluate in vitro the cleaning of root-canal walls after irrigation with different irrigants. METHODOLOGY: A total of 36 recently extracted human teeth were divided into four experimental groups according to the irrigating solution used: saline; 2% chlorhexidine; 2.5% sodium hypochlorite; and 2.5% sodium hypochlorite + EDTA. The cleaning of the apical, middle and coronal thirds of the root canals was evaluated by scanning electron microscope examination using a 4-point scoring system. RESULTS: The best cleaning was obtained using 2.5% sodium hypochlorite and EDTA, followed by 2.5% sodium hypochlorite only (P < 0.05), whose cleaning was similar to chlorhexidine only in the cervical third. Cleaning by saline and 2% chlorhexidine was worse than the other two groups and was similar in all thirds. Better cleaning was found in the cervical and middle thirds for all groups with the worst results in the apical third. CONCLUSIONS: The apical third of the root canals was not cleaned as well as the middle and coronal thirds. Cleaning by chlorhexidine and saline was inferior compared to the cleaning by sodium hypochlorite with and without EDTA.     

A SEM study of canal cleanliness after a new nickel-titanium rotary instrumentation technique

The purpose of this in vitro study was to evaluate the degree of smear layer removal after root canal preparation with TF(?) instruments, combined with two different irrigating solutions.For the present study twenty-two freshly extracted human roots were selected. All teeth had been extracted for periodontal purpose. Crown were cut off with a separating disk, so all roots were approximately 10-12 mm long.After having chosen the two control roots, the remaining ones were randomly divided into two groups each containing 10 roots. The two experimental groups were prepared as follows.A crown-down instrumentation technique was used, following TF(?) manufacturer's instructions.Irrigation of Group A consisted of 2 ml of solution: 6% sodium hypochlorite (Chlor-Extra(?), Vistadental Racine, Mi, USA) after each instrument followed at the end by a 17% EDTA minute (Smear Clear(?), SybronEndo, Orange, Ca) irrigation for 1 min. Both irrigants contain tensioactive agents.Group B specimens were irrigated with 2 ml of sterile saline solutions after each instrument. Two control roots were not instrumented and irrigated. Teeth were then examined by scanning electron microscopy.Values obtained were tabulated and statistical analyses were carried out using a non parametric tests.RESULTS SHOWS SIGNIFICANT DIFFERENCES IN THE MEAN SCORE BETWEEN THE TWO GROUPS: most experimental group A canals showed clean or minimal debris in the observed areas, especially in the coronal and middle thirds.     

A scanning electron microscopic evaluation of different root canal irrigation regimens

The purpose of this study was to assess the effectiveness of endodontic irrigants in removing the smear layer from instrumented root canal walls using Scanning Electron Microscopy (SEM). The endodontic irrigants used were: 1% sodium hypochlorite (NaOCl); 1% NaOCl mixed to 17% EDTAC; 2% chlorhexidine gel; and Ricinus communis gel. Photomicrographs of the middle and apical thirds were evaluated with the aid of the Fotoscore - v. 2.0 software. The results indicated that the mixture of sodium hypochlorite and EDTAC completely removed the smear layer from dentinal walls. The other endodontic irrigants were not as efficient in cleansing the root canals.     

The effect of application time of EDTA and NaOCl on intracanal smear layer removal: an SEM analysis

AIM: To verify, under the scanning electron microscope (SEM), the influence of irrigation time with ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl) on intracanal smear layer removal. METHODOLOGY: Twenty-one extracted human permanent teeth with single straight root canals were included. The root canals of the teeth were instrumented and, at the end of preparation, were irrigated with 3 mL of 15% EDTA, followed by 3 mL of 1% NaOCl for 1 min (group 1), for 3 min (group 2), and for 5 min (group 3). The canals of teeth in group 4 (control) did not receive the final irrigation. The teeth were sectioned longitudinally and prepared for an SEM. The dentinal wall of cervical, middle and apical thirds was graded according to the amount of debris and smear layer remaining on the walls. The results were analysed using the Kruskal-Wallis and Conover-Inman tests. RESULTS: In all the canals of experimental groups irrigation with EDTA and NaOCl completely removed the smear layer from the cervical and middle thirds. In the apical third, the dentine surface were partially covered, particularly in the teeth of group 1, where there was significantly more smear layer when compared with the other thirds in the same group (P<0.007). However, the Kruskal-Wallis test showed overall that there were no significant differences between groups 1, 2 and 3 (P>0.05). CONCLUSION: In this limited laboratory study, canal irrigation with EDTA and NaOCl for 1, 3 and 5 min were equally effective in removing the smear layer from the canal walls of straight roots.     

The effect of different irrigation protocols on smear layer removal in root canals of primary teeth: a SEM study

Objective: The purpose of this study was to compare the efficacy of different irrigation protocols on smear layer removal in root canals of primary teeth by scanning electron microscopy (SEM).

Material and methods: The study was conducted with 40 extracted maxillary primary incisor teeth divided into four groups (n?=?10) as 1% sodium hypochlorite (NaOCl), 10% ethylenediaminetetraacetic acid (EDTA)+1% NaOCl, 6% citric acid (CA)+1% NaOCl, and 0.9% physiological saline (PS). After the irrigation procedures, root canal walls were examined by SEM and the efficacies of irrigation solutions in smear layer removal were scored and compared. Data were analyzed using Kruskal–Wallis, Friedman and Siegel Castellan tests.

Results: The smear layer removal was found to be statistically more effective in groups of 10% EDTA + 1% NaOCl and 6% CA + 1% NaOCl when compared with the other groups (p?<?.05). Smear removal efficacy was statistically significantly higher in coronal and medium thirds when compared with the apical regions in the experimental groups.

Conclusions: It was concluded that 10% EDTA + 1% NaOCl and 6% CA + 1% NaOCl could be alternative irrigation protocols regarding smear layer removal. However, due to the absence of erosive dentinal changes, it might be suggested that using 6% CA + 1% NaOCl can be recommended compared to 10% EDTA + 1% NaOCl in primary root canals.     

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.     

Glyde凝胶在乳磨牙根管预备中的作用

目的 通过根管充填程度来评价Glyde凝胶在乳磨牙根管预备中的效用.方法 患儿37人,患牙39颗,根管115只,按上下颌随机分成两组,Glyde组:用Glyde凝胶配合常规根管预备,共57只根管;对照组:只用常规根管预备,共58只根管.根管充填后X片检查,观察充填程度.结果 适填:Clyde组33只根管(57.9%),对照组10只根管(17.2%);欠填:Glyde组7只根管(12.3%),对照组32只根管(55.2%);超填:Glyde组15只根管(26.3%),对照组14只根管(24.1%).两组X2检验有显著性差异(P＜0.05).结论 Glyde凝胶在乳磨牙根管预备中,能有效协助扩大狭窄弯曲根管,为满意的根管充填创造良好条件.     

Calcium ion diffusion from mineral trioxide aggregate through simulated root resorption defects.

The purpose of this study was to investigate the diffusion of calcium ions (Ca+2) through exposed dentinal tubules following intracanal application of mineral trioxide aggregate (MTA). Fifty-two single-rooted teeth were instrumented using 2.5% sodium hypochlorite for irrigation between each file size. Thereafter, standardized defects were created on the root surfaces so as to mimic external root resorption. The root canals and external defects received a final irrigation of 17% ethylenediaminetetraacetic acid and distilled water. MTA powder was then mixed with saline and placed into the canals. All root surfaces except the cavities were sealed with two coats of varnish. Teeth with unfilled canals (n = 26) served as controls. The teeth were immersed in saline after which the release of Ca+2 from the defects into the saline was measured at 1, 3, 7, 14, and 28 days. The results showed diffusion of Ca+2 through the defects in the dentin in MTA-filled roots with a significant increase in concentration within time.     

Chelation in root canal therapy reconsidered

The aim of this study was to assess interactions of EDTA and citric acid (CA) with sodium hypochlorite (NaOCl), the indispensable endodontic irrigant. Other chelators were simultaneously evaluated as possible alternatives: sodium triphosphate (STP), amino tris methylenephosphonic acid (ATMA), and 1- hydroxyethylidene-1, 1-bisphosphonate (HEBP). Available chlorine was titrated in chelator-NaOCl solutions. All chelators other than HEBP and STP caused an almost complete, immediate loss of available chlorine in solution. Atomic absorbtion spectrometry and SEM evaluation of root canal walls of instrumented teeth indicated that NaOCl had no negative effect on calcium-complexing ability of chelators. STP was too weak a complexing agent to warrant further studies. Finally, CA-, EDTA-, and HEBP-NaOCl mixtures were evaluated for their antimicrobial capacity. Again, EDTA and CA negatively interfered with NaOCl, while HEBP did not.     

不同质量分数乙二胺四乙酸糊剂对根管壁不同区域玷污层的去除效果评价

目的研究不同质量分数乙二胺四乙酸（EDTA）糊剂去除根管壁玷污层的效果以及对根管壁的腐蚀作用。方法选择60颗离体单根管牙,用逐步后退法预备根管,预备后随机分成6组,采用不同质量分数的EDTA糊剂对根管进行处理,分别为5%、10%、15%、17%和20%EDTA糊剂,另设生理盐水组作为对照。处理时先将EDTA糊剂输送进根管内,作用3 min后以5.25%次氯酸钠溶液冲洗,次氯酸钠溶液用量为5 mL。处理后将牙根沿颊舌向纵向劈开,用扫描电镜观察根管壁不同部位玷污层的去除效果和牙本质的腐蚀状况,分别进行评分。结果随着EDTA糊剂质量分数的增加,对根冠1/3、根中1/3玷污层的去除效果明显增加。15%EDTA糊剂可以有效地去除根冠1/3和根中1/3的玷污层,根尖1/3去除效果稍差;对根管壁无明显的腐蚀破坏现象。17%和20%的EDTA糊剂对玷污层的去除效果明显,但对根管壁的结构造成了一定的腐蚀破坏。结论经不同质量分数的EDTA糊剂处理,根管壁玷污层的去除效果不同;质量分数大于17%的EDTA糊剂会对根管壁造成腐蚀。     

Influence of different auxiliary agents of biomechanical preparation in the filling of "artificially prepared" lateral canals

The purpose of the present study was to evaluate the influence of some auxiliary agents of biomechanical preparation of the root canal on the filling of artificial lateral canals in extracted human teeth. A total of eighty single-rooted teeth were employed, which were submitted to preparation of three artificial lateral canals in one of the proximal aspects at the cervical, middle and apical thirds, besides one in the buccal aspect. The main canals were prepared by Profile 0.4 rotary instruments through the crown-down technique and irrigated with the irrigants investigated, as follows: Group A - 1% sodium hypochlorite and final irrigation with trisodium EDTA for 5 minutes; Group B - Endogel (2% chlorhexidine gel); Group C - Endo PTC and Dakin's solution and final irrigation with Tergentol- Furacin; and Group D - File Eze. The root canals were obturated by the Tagger's hybrid technique and then radiographed for assessment of the penetration rate of the filling materials in the lateral canals. Analysis of the results demonstrated no statistically significant difference (p<0.05) between the irrigants both to each other and as regards the location (thirds and aspects) of the artificial lateral canals.     

Assessment of smear layer removal protocols in curved root canals

This study sought to assess if the final rinse protocol interferes with the smear layer removal in the apical area of curved canals. Sixty‐four extracted human mandibular molars with curved mesial roots were instrumented with rotary files and divided into six experimental groups for final rinse: 1EDTA (syringe irrigation with 1 mL of 17% ethylenediaminetetraacetic acid (EDTA) ), 5EDTA (syringe irrigation with 5 mL of 17% EDTA), 1EDTA‐P (syringe irrigation with 1 mL of 17% EDTA + pumping with gutta‐percha point), 5EDTA‐P (syringe irrigation with 5 mL of 17% EDTA + pumping with gutta‐percha point), 1EDTA‐EA (syringe irrigation with 1 mL of 17% EDTA + EndoActivator) and 5EDTA‐EA (syringe irrigation with 5 mL of 17% EDTA + EndoActivator). Final rinsing was carried out over 3 min. The specimens were split lengthwise and observed under a scanning electron microscope using a score criterion. Comparison among the groups showed statistically significant difference only between the 5EDTA‐EA group and the other groups (Kruskal–Wallis and Dunn's post‐hoc tests, P < 0.05). The combination of 5 mL of 17% EDTA and 3 mL of 2.5% sodium hypochlorite (NaOCl) with the EndoActivator removed smear layer from the apical area of curved root canals more effectively than the other protocols used.     

The effects of calcium hydroxide removal methods on bond strength of Epiphany SE with two irrigation protocols

Abstract

Objective: The purpose of this study was to compare the effects of five calcium hydroxide removal methods on the bond strength of Epiphany SE sealer after canal irrigation with NaOCl+EDTA or NaOCl+MTAD. Materials and methods: The 120 roots were instrumented by using the ProTaper rotary system under irrigation with 2.5% sodium hypochlorite and randomly divided into two major groups according to the final irrigation: 1.3% NaOCl + MTAD and 5% NaOCl + 17% EDTA. For controls, 10 roots from each of the final irrigations with NaOCl + MTAD and NaOCl + EDTA (20 roots) were not filled with Ca(OH)₂. The intra-canal paste, Ca(OH)₂ was applied to each of the 100 remaining roots and stored at 37°C for 7 days. Each group was sub-divided into five sub-groups (n = 10) according to the removal technique for the intra-canal dressing: Group-1: recapitulation with size 30 K file + 3 ml of saline solution, Group-2: recapitulation with size 30 K file + 3 ml of 5% NaOCl, Group-3: using 5% NaOCl + 17% EDTA, Group-4: using 5%NaOCl + 15% citric acid, and Group-5: using 1.3% NaOCl + 5 ml MTAD. The root canals were filled with Resilon and Epiphany SE sealer. The bond strength was measured. Results: The mean bond strength of Epiphany SE to root dentine irrigated with NaOCl + MTAD was lower than that of NaOCl + EDTA. The highest bond strengths were 3.31 ± 0.057 and 2.60 ± 0.054 in the NaOCl + citric acid group when Ca(OH)₂ was applied to roots treated with NaOCl + EDTA and NaOCl + MTAD, respectively (p < 0.05). Conclusion: For root canals treated with NaOCl + EDTA or NaOCl + MTAD, the use of NaOCl + chelating agent for Ca(OH)₂ removal does not adversely affect the bond strength of Epiphany SE to dentin.     

Etidronate from Medicine to Endodontics: effects of different irrigation regimes on root dentin roughness

An increase in dentin roughness, associated with surface composition, contributes to bacterial adherence in recontaminations. Surface roughness is also important for micromechanical interlocking of dental materials to dentin, and understanding the characteristics of the surface is essential to obtain the adhesion of root canal sealers that have different physico-chemical characteristics.

Objectives

To evaluate the effects of sodium hypochlorite (NaOCl), ethylenediaminetetraacetic (EDTA), etidronic (HEBP), and citric acid (CA) associated with different irrigation regimens on root dentin roughness.

Material and Methods

Forty-five root halves of anterior teeth were used. The root parts were sectioned in thirds, embedded in acrylic resin and polished to a standard surface roughness. Initially, the samples of each third were randomly assigned into 3 groups and treated as follows: G1 - saline solution (control); G2 - 5% NaOCl+18% HEBP mixed in equal parts; and G3 - 2.5% NaOCl. After initial measuments, the G3 samples were distributed into subgroups G4, G5 and G6, which were subjected to 17% EDTA, 10% CA and 9% HEBP, respectively. Following the new measuments, these groups received a final flush with 2.5% NaOCl, producing G7, G8 and G9. The dentin surface roughness (Ra) was determined before and after treatments using a profilometer. The Wilcoxon test (α<0.05) was used to compare the values before and after treatments, and the Friedman test (α<0.05) to detect any differences among root thirds.

Results

(i) NaOCl did not affect the surface roughness; (ii) there was a significant increase in roughness after the use of chelating agents (P<0.01); and (iii) only the G3 group showed a difference in surface roughness between apical third and other thirds of the teeth (P<0.0043).

Conclusion

Only the irrigation regimens that used chelating agents altered the roughness of root dentin.     

Effectiveness of oxidative potential water as a root canal irrigant

AIM: The aim of this study was to evaluate the effectiveness of oxidative potential water (OPW) as an irrigant, based on its ability to remove the smear layer and/or debris from instrumented root canals. METHODOLOGY: One hundred and twenty root canals from extracted human maxillary incisors were instrumented using a conventional step-back technique with irrigation from sodium hypochlorite (NaOCl) or oxidative potential water (OPW). After instrumentation, the canals were irrigated by syringe or ultrasound using 15% EDTA or OPW as an irrigant. The volume of each irrigant used for syringe irrigation was 10, 20, and 30 mL, respectively, whilst the duration for ultrasonic irrigation was 1, 3, and 5 min, respectively. After irrigation, each root was split longitudinally in two with cutting pliers, and the specimens were prepared for SEM observation. The presence of debris and smear layer on each canal wall was assessed using a three-point scale for each parameter. RESULTS: Smear layer was effectively removed with EDTA both introduced via syringe and via ultrasonic irrigation. A similar effect was observed with OPW via syringe irrigation following instrumentation with 5% NaOCl. The canal walls in any of these cases showed open and patent dentinal tubules following smear layer removal. Some specimens irrigated with EDTA exhibited the effect of demineralization on the dentine resulting in funnelling of tubule orifices. Syringe irrigation was more effective in smear layer removal, except for ultrasonic irrigation with 15% EDTA, whilst ultrasonic irrigation was more effective in debris removal including the use of OPW as irrigant following instrumentation with 5% NaOCl. Neither syringe nor ultrasonic irrigation with OPW following instrumentation with OPW removed smear layer or debris effectively. CONCLUSIONS: The most effective irrigation technique for smear removal was 15% EDTA irrigation by means of syringe following instrumentation with 5% NaOCl solution. However, the most effective irrigation technique for debris removal was ultrasonic irrigation regardless of irrigant used. OPW irrigation by means of syringe following instrumentation with 5% NaOCl showed a similar effect to that of 15% EDTA irrigation for removal of smear layer and debris.