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The aim of this study was to evaluate the effect of peracetic acid (PAA) as a single irrigant on the smear layer, on the intraradicular dentinal bond strength, and on the penetrability of an epoxy-based resin sealer into the dentinal tubules. A total of 120 roots were distributed into 4 groups according to the irrigant used in root canal preparation: 1% PAA (PAA); 2.5% NaOCl followed by final irrigation with 17% EDTA and 2.5% NaOCl (NaOCl-EDTA-NaOCl); 2.5% NaOCl (NaOCl); and saline solution (SS). The smear layer was evaluated using scanning electron microscopy. The bond strength of an epoxy-based resin sealer (AH Plus) to root dentin was evaluated by the push-out test and penetrability of the sealer into dentinal tubules was observed by confocal laser microscopy. The results were analyzed by the Kruskal-Wallis and the Dunn post-test (α = 0.05). The use of 1% PAA as single root canal irrigant provided smear layer removal and improved the penetrability and bond strength of AH Plus to root dentin in a manner similar to that of the NaOCl-EDTA-NaOCl group (p > 0.05). The NaOCl and SS groups had higher values of smear layer and lower values of sealer penetrability and dentin bond strength than the PAA and NaOCl-EDTA-NaOCl groups (p < 0.05). Thus, 1% PAA has the potential to be used as a single irrigant in root canals.

Objective: This in vitro study aimed to compare the efficacy of irrigants using various irrigation activation methods to the push-out bond strengths of fiber post to root canal luted with self-adhesive resin cement (SARC)., Methodology: Forty-eight decoronated human canines were used. The specimens were divided into four groups corresponding with the post-space irrigation process and were treated as follows: distilled water (DW) (Control) group received 15 mL of DW; sodium hypochlorite (NaOCl)+ethylenediaminetetraacetic acid (EDTA) group was treated with 5 mL of 5.25% NaOCl, 5 mL of 17% EDTA, and 5 mL of DW; passive ultrasonic irrigation (PUI) group was treated with 5 mL of 5.25% NaOCl, 5 mL of 17% EDTA, and 5 mL of DW, and each irrigant was agitated with an ultrasonic file; and laser activated irrigation (LAI) group was treated with 5 mL of 5.25% NaOCl, 5 mL of 17% EDTA, and 5 mL of DW, and each irrigant was irradiated with Nd: YAG laser. Fiber posts were luted with SARC, and a push-out test was performed. Data was analyzed using one-way analysis of variance and Tukey HSD test., Results: The bond strength values for the groups obtained were as follows: Control (10.04 MPa), NaOCl+EDTA (11.07 MPa), PUI (11.85 MPa), and LAI (11.63 MPa). No statistically significant differences were found among all experimental groups (p>0.05). The coronal (12.66 MPa) and middle (11.63 MPa) root regions indicated a significantly higher bond strength compared with the apical (9.16 MPa) region (p<0.05)., Conclusions: Irrigant activation methods did not increase the bond strength of fiber post to canal.

This study evaluated the effect of previous irrigation with chlorhexidine (CHX) on the bond strength of a calcium silicate-based material, Biodentine, when used for furcal repair. Furcal perforations were produced in 30 extracted mandibular molars. Teeth were divided into 3 groups according to the irrigant used: distilled water (DW), CHX followed by DW (CHX), and CHX followed by ethylenediaminetetraacetic acid (EDTA) and DW (CHX/EDTA). Biodentine was used to repair the perforations. A push-out bond strength test was performed after 7 days, and data were statistically analyzed using Kruskal-Wallis and Dunn tests (P < 0.05). The CHX/EDTA group showed significantly lower values than the DW and CHX groups (P < 0.05). The failure mode of the DW group was mainly mixed, while that of the CHX group was cohesive. The CHX/EDTA group exhibited adhesive and mixed failures. Irrigation with CHX prior to furcation repair did not result in a statistically significant difference, compared to the use of DW, in the push-out bond strength of Biodentine., Competing Interests: The authors report no conflicts of interest pertaining to any of the products or companies discussed in this article.

The objective of this study was to assess the influence of chlorhexidine (liquid and gel) and zinc oxide in calcium hydroxide (CH) pastes on root pH in simulated external resorption. One hundred human anterior teeth with a single root canal were selected. After decoronation and root canal instrumentation, the specimens were divided into 4 experimental groups and 1 control group (without intracanal paste): CH + saline (CH+S), CH + 2% chlorhexidine liquid (CH+ CHX), CH + 2% chlorhexidine gel (CH+ CHXg), and CH + 2% chlorhexidine gel + zinc oxide (CH+ CHXg+ZnO). pH was measured using a microelectrode at 3 and 24 h, and 1, 2, 3, and 4 weeks after inserting intracanal pastes. Data were analyzed statistically using an ANOVA and Tukey's test (p < 0.05). The CH+CHXg+ZnO group had the highest pH values throughout (p<0.05). The CH+S and CH+ CHX groups had the highest pH values after 1 week and the CH+ CHXg group after 2 weeks. CH+ CHXg maintained the highest pH until the fourth week compared with CH+ CHX (p < 0.05). The control group remained at a neutral pH at all evaluated times. It can be concluded that chlorhexidine solution or gel maintained the alkaline pH of CH, and chlorhexidine gel allowed a slower decrease in pH over time. CH+ CHXg+ZnO showed the highest pH values and was an effective intracanal medication for maintaining alkaline root pH in the area of resorption.

Objective: To evaluate the efficacy of different sonic and ultrasonic devices in the elimination of debris from canal irregularities in artificial root canals., Materials and Methods: A resin model of a transparent radicular canal filled with dentin debris was used. Five groups were tested, namely: Group 1 - ultrasonic insert 15.02; Group 2 - ultrasonic insert 25/25 IRRI K; Group 3 - ultrasonic insert 25/25 IRRI S; Group 4 - sonic insert 20/28 Eddy on a vibrating sonic air-scaler handpiece; Group 5 - 20.02 K-file inserted on a Safety M4 handpiece. Two different irrigants (5% sodium hypochlorite and 17% EDTA) and 3 different times of activation (20, 40, and 60 seconds) were tested. Means and standard deviations were calculated and statistically analyzed with the Kruskal-Wallis and Wilcoxon tests (p<0.05)., Results: No statistically significant differences were found between the two irrigants used. Group 4 removed more debris than the other groups (p<0.05). Groups 1, 2, and 3 removed more debris than group 5 (p<0.05). A statistically significant difference (p<0.05) was found for the time of activation in all groups and at all canal levels, except between 40 and 60 seconds in group 4 at coronal and middle third level (p>0.05)., Conclusions: No significant differences were found between 5% sodium hypochlorite and 17% EDTA. When the time of activation rises, the dentin debris removal increases in all groups. Both sonic and ultrasonic activation demonstrate high capacity for dentin debris removal.

Objectives: The aim of this study was to evaluate the influence of surfactants 0.2% or 0.1% cetrimide (Cet) or 0.008% benzalkonium chloride (BAK) on 2.5% calcium hypochlorite (Ca(OCl)2), and compare to sodium hypochlorite (NaOCl), regarding the properties of pH, free chlorine content, surface tension, contact angle, pulp dissolution and antimicrobial activity., Material and Methods: The pH and free chlorine content were evaluated by digital pHmeter and by titration, respectively. Surface tension was measured by the platinum ring technique with a Du Noüy tensiometer. The solution's contact angle in human dentin surfaces was checked by Drop Shape Analyzer software. Bovine pulps were used for pulp dissolution analysis and the dissolving capacity was expressed by percent weight loss. Antimicrobial activity over Enterococcus faecalis was evaluated by the agar diffusion method., Results: Surfactants addition to Ca(OCl)2 and NaOCl did not alter the pH, free chlorine content and pulp dissolution properties. Ca(OCl)2 had the highest surface tension among all tested solutions. When surfactants were added to Ca(OCl)2 and NaOCl, there was a significant reduction of surface tension and contact angle values. The addition of 0.2% or 0.1% Cet enhanced antimicrobial activity of both Ca(OCl)2 and NaOCl., Conclusion: Surfactant addition to 2.5% Ca(OCl)2 has shown acceptable outcomes for pH, free chlorine content, surface tension, contact angle, pulp dissolution and antimicrobial activity. Furthermore, the addition of 0.2% Cet showed better results for all tested properties.

The objective of this study was to evaluate the effect of sodium hypochlorite and chlorhexidine solutions and their inactivating agents on the push-out bond strength of mineral trioxide aggregate (MTA). One hundred fifty root slices were prepared and their root canal spaces were enlarged using diamond burs. MTA was prepared and compacted to root canal spaces. The samples were randomly separated to 4 groups that would be immersed into the selected solutions (5.25% sodium hypochlorite (NaOCl), 5.25% NaOCl and sodium thiosulfate, 2% chlorhexidine (CHX), 2% CHX and a mixture of Tween 80 and 0.3% L-alfa-lecithin) and a control group (n = 30). Push-out bond strength of each specimen was tested with universal testing machine. The data was analyzed by one-way analysis of variance and Tukey tests. There were no significant differences between the push-out bond strength values of the irrigation groups and the control group. A significant difference was found between the push-out bond strength values of NaOCl-Sodium thiosulfate and CHX-L-alpha-lecithin groups. Contact with NaOCl and its neutralizing agent with MTA after 10 minutes of setting period increased the push-out bond strength of MTA. On the other hand, any contact with CHX alone or with subsequent application using L-alfa-lecithin should be avoided since that might decrease the push-out bond strength of freshly mixed MTA.

The aim of this study was to evaluate the influence of radiation therapy on root canal sealer push-out bond strength (BS) to dentin and the sealer/dentin interface after different final irrigation solutions (NaOCl, EDTA, and chitosan). Sixty-four maxillary canines were distributed into two groups (n=30): non-irradiated and irradiated with 60 Gy. Canals were prepared with Reciproc-R50 and subdivided (n=10) for final irrigation (NaOCl, EDTA, chitosan) and filled. Three dentin slices were obtained from each root third. The first slice of each third was selected for BS evaluation, and the failure mode was determined by stereomicroscopy. SEM analysis of the sealer-dentin interface was performed in the remaining slices. Two-way ANOVA and Tukey's tests (α=0.05) were used. Lower BS (P<0.0001) was obtained after irradiation (2.07±0.79 MPa), regardless of the final irrigation solution used. The NaOCl group (P<0.001) had the lowest BS in the irradiated (1.68±0.72) and non-irradiated (2.39±0.89) groups, whereas the EDTA (irradiated: 2.14±0.77 and non-irradiated: 3.92±1.54) and chitosan (irradiated: 2.37±0.73 and non-irradiated: 3.51±1.47) groups demonstrated a higher BS (P<0.05). The highest values were observed in the coronal third (3.17±1.38) when compared to the middle (2.74±1.36) and apical ones (2.09±0.97)(P<0.0001). There were more cohesive failures and more gaps in irradiated specimens, regardless of the final solution. The present study showed that radiation was associated with a decrease in BS, regardless of the final solution used, whereas chitosan increased BS in teeth subjected to radiation therapy.

Introduction: SmearOFF (Vista Dental Products, Racine, WI) is an irrigation solution containing chlorhexidine (CHX), EDTA, and a surfactant. This study examined the chemical interaction of SmearOFF with sodium hypochlorite (NaOCl) on the dentin surface, specifically the formation of precipitate and/or parachloroanaline (PCA)., Methods: Dentin blocks prepared from human maxillary molars were mounted in resin. Dentinal tubules were exposed in a perpendicular orientation using an ultracryomicrotome. The blocks were divided into 2 groups: the CHX group, irrigation with 6% NaOCl, 17% EDTA, 6% NaOCl, and 2% CHX, and the SmearOFF group, irrigation with 6% NaOCl and SmearOFF. The dentin surface was analyzed with time-of-flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy to determine the formation of precipitate or/and PCA on the surface of dentin., Results: Precipitation with PCA and occlusion of the dentinal tubules were noted on the dentin surface in the CHX group. No precipitate and no PCA were detected on the surface of dentin in the SmearOFF group., Conclusions: Interaction of SmearOFF with NaOCl on the dentin surface did not result in the formation of precipitate or PCA., (Copyright © 2018 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Root canal irrigation with sodium hypochlorite (NaOCl) is an indispensable part of the chemomechanical preparation of infected root canals in Endodontology. However, there is limited information on the emergence of toxic or hazardous volatile compounds (VOCs) from the interaction of NaOCl with the infected content of tooth biomaterials. The aim of this study was to assess the formation of VOCs and disinfection by-products (DBPs) following the interaction of NaOCl 2.5% v/v with a model system of different sources of natural organic matter (NOM) present in infected root canals, including dentine powder, planktonic multi-microbial suspensions (Propionibacterium acnes, Staphylococcus epidermidis, Actinomyces radicidentis, Streptococcus mitis and Enterococcus faecalis strain OMGS3202), bovine serum albumin 4%w/v and their combination. NaOCl was obtained from a stock solution with iodometric titration. Ultrapure water served as negative control. Samples were stirred at 37°C in aerobic and anaerobic conditions for 30min to approximate a clinically realistic time. Centrifugation was performed and the supernatants were collected and stored at -800 C until analysis. The reaction products were analysed in real time by selected ion flow tube mass spectrometry (SIFT-MS) in triplicates. SIFT-MS analysis showed that the released VOCs included chlorinated hydrocarbons, particularly chloroform, together with unexpected higher levels of some nitrogenous compounds, especially acetonitrile. No difference was observed between aerobic and anaerobic conditions. The chemical interaction of NaOCl with NOM resulted in the formation of toxic chlorinated VOCs and DBPs. SIFT-MS analysis proved to be an effective analytical method. The risks from the rise of toxic compounds require further consideration in dentistry., Competing Interests: The author affiliation to Trans Spectra Limited does not alter our adherence to PLOS ONE policies on sharing data and materials.

The aim of this study was to evaluate the effect of post-space irrigation with NaOCl and CaOCl at different concentrations on the bond strength of posts cemented with a self-adhesive resin cement. Eighty premolars were sectioned 14 mm from the apex, and endodontically treated. The root canal filling was partially removed. Specimens were randomly assigned into 8 groups (n=10), according to the irrigant for post-space irrigation: SS - 0.9% saline solution (control group); CHX - 2% chlorhexidine; 1% NaOCl - 1% sodium hypochlorite; 2.5% NaOCl - 2.5% sodium hypochlorite; 5% NaOCl - 5% sodium hypochlorite; 1% CaOCl - 1% calcium hypochlorite; 2.5% CaOCl - 2.5% calcium hypochlorite; and 5% CaOCl - 5% calcium hypochlorite. For each group, irrigation was performed continuously with 2 ml of solution. The post-spaces were dried with paper points (#80), and glass fiber posts were cemented using a self-adhesive resin cement. The specimens were sectioned perpendicularly and the push-out test was performed. Optical microscopy was used to analyze the failure mode. ANOVA and Bonferroni tests analyzed the bond strength data. NaOCl and CaOCl presented similar bond strength regardless the concentration used to irrigate the post-space (p>0.05). SS showed the highest bond strength (11.47 MPa) (p<0.05). Adhesive failures at the cement/dentin interface were predominant (58.33%). Saline solution should be irrigant of choice to irrigate the post-space before fiber post cementation with self-adhesive resin cement. NaOCl and CaOCl negatively affect the bond strength values.

Statement of Problem: The optimal irrigating solution with antimicrobial and dentin cleansing properties for post space preparation for fiber posts is unclear. Peracetic acid is one option but is available in various chemical formulations that require evaluation., Purpose: The purpose of this in vitro study was to evaluate dentin surface cleanliness based on the presence of a smear layer and the number of open dentin tubules. It also investigates the chemical composition of residues after canal irrigation with a 1% peracetic acid solution (PA) at low or high concentration of hydrogen peroxide during the preparation of intracanal fiber posts., Material and Methods: After filling the root canals of 40 mandibular incisors, a rotary instrument was used for intracanal preparation to place fiber posts. The teeth were divided into 4 groups (n=10) according to the post space irrigation protocol as follows: CG (control): distilled water; NA (NaOCl): 2.5% sodium hypochlorite; LH: PA with low concentration of hydrogen peroxide; and HH: PA with high concentrations of hydrogen peroxide. After irrigation, the teeth were sectioned, and the intracanal dentin surface was subjected to analysis using energy dispersive spectroscopy to evaluate chemical composition and to scanning electron microscopy (×500) to evaluate the presence of the smear layer. The number of open dentin tubules was measured by scanning electron microscopy analysis (×2000) using photo-editing software. ANOVA and the Tukey test (α=.05) were used to evaluate the data, except for the presence of a smear layer, for which the Kruskal-Wallis and Dunn tests were used (α=.05)., Results: The highest concentrations of oxygen in the dentin residues were detected in LH and HH (P<.05); CG and NA showed similar oxygen concentrations (P>.05). NA had a higher concentration of chlorine (P<.05), whereas LH had a lower amount of smear layer and a larger number of open dentin tubules than the other groups (P<.05). These were equivalent to each other (P>.05), except for HH, which also had a larger number of open dentin tubules than CG and NA (P<.05)., Conclusions: PA 1% with a low concentration of hydrogen peroxide yielded a lower amount of smear layer and a larger number of open dentin tubules in the dentin of the post space when compared with PA 1% with a high concentration of hydrogen peroxide, despite maintaining a similar oxygen concentration in these dentin residues., (Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Aims: The purpose of the present study was to develop techniques to evaluate and quantify the primary components of dental medicament paste mixtures for root canal treatment, and to evaluate if degradation of the primary components occurred during storage., Methods: The first part of the study developed a mass spectrometry (MS) method for determination of best recovery process. For this process, analytical grades of triamcinolone acetonide, clindamycin HCl, and doxycycline hyclate were sourced and analyzed. This was followed by solid-phase extraction (SPE) and an analysis of active components in dental pastes., Results: By utilizing the targeted analytical properties of multiple reaction monitoring MS methods, coupled with SPE technique, the active components of endodontic dental pastes could be quantified and compared. The developed methods showed consistency over multiple runs, with a high level of reproducibility. None of the active components of the tested pastes degraded over the periods of product life tested., Conclusion: The inactivation or destruction of any of the primary components of endodontic medicaments in storage, or when mixed with other pastes, could affect treatment outcomes. The present study provides a reliable technique for the analysis of the active components of root canal medicaments., (© 2017 John Wiley & Sons Australia, Ltd.)

Objectives: This is to compare the volumes of irrigant apically extruded by five irrigation systems in an artificial socket model simulating clinical conditions., Materials and Methods: Twenty extracted human single-rooted teeth were enlarged to size 40/04 and then embedded in silicone impression material. The root canal space was irrigated with nominal 3% sodium hypochlorite (NaOCl) using standard needle irrigation (SNI) with a 30-gauge notched needle, EndoActivator (EA), XP Endo Finisher (XP Endo), EndoVac (EV), and photon-induced photoacoustic streaming (PIPS). Extruded NaOCl was collected, reacted with taurine to form taurine-monochloramine, and absorbance of taurine-monochloramine was measured at 252 nm using a spectrophotometer. The five irrigation systems were compared with repeated measures ANOVA and pairwise comparisons., Results: The EV group had very low extrusion (mean ± SD = 0.12 ± 0.2 μL) and differed significantly from the other four groups (P ≤ 0.001). Larger volumes of irrigant were extruded in the other irrigation groups. There were no significant differences in the extruded volumes among the SNI (7.4 ± 3.4 μL), EA (7.0 ± 6.1 μL), and XP Endo (7.8 ± 4.1 μL) groups (P = 1). The PIPS group had the highest mean extruded volume (12.9 ± 6.8 μL) and differed significantly from SNI (P = 0.030), EV (P < 0.0005), and EA (P = 0.02), but not XP Endo (P = 0.154)., Conclusion: Under the in vitro conditions of this study, irrigant extrusion appears unavoidable unless negative pressure irrigation such as EV is used. PIPS extrudes more irrigant than other systems, while SNI, EA, and XP Endo extrude similar volumes of irrigant., Clinical Relevance: The findings help clinicians select the optimal irrigation system to avoid irrigant extrusion.

The purpose of this study was to compare the efficacy of different chelating solutions (17% EDTA and 10% citric acid) on the smear layer removal, and their effect on tubular dentin sealer penetration. Sixty root canals were prepared and distributed into four groups (n = 15) according to the final irrigation protocol: G1, final irrigation with 2.5 mL of distilled water; G2, final irrigation with 2.5 mL of 2.5% sodium hypochlorite solution; G3, final irrigation with 2.5 mL of 17% EDTA; and G4, final irrigation with 2.5 mL of 10% citric acid. Five specimens from each group were not filled to assess smear layer removal by scanning electron microscopy. Ten specimens from each group were filled for analysis of sealer penetration into dentinal tubules by confocal laser scanning microscopy. Smear layer removal (Kruskal-Wallis and Dunn's tests) and sealer penetration (F and Tukey's tests) were statistically analyzed with 95% of significance level. G3 and G4 had greater smear layer removal rates in the cervical and middle thirds, in comparison with G1 and G2 (p < .05). G3 and G4 had the highest percentages of sealer penetration in all thirds, in comparison with G1 and G2 (p < .05). Smear layer removal was effective only at the cervical and middle thirds when the chelating solutions were used. Sealer penetration into the dentinal tubules significantly increased in all root thirds when the specimens were treated with both chelating solutions., (© 2017 Wiley Periodicals, Inc.)

Objectives: Chlorhexidine binds to dentine to provide sustained action. The aim of the present study was to evaluate and compare the substantivity of chlorhexidine using manual, rotary, and reciprocating systems for root canal preparation., Methods: Forty-five extracted human single-rooted teeth were used for this study. The samples were divided into three groups (n = 15) according to the instrumentation technique used: manual instrumentation (K-File), rotary instrumentation (ProTaper), and reciprocating instrumentation (Reciproc R25). Chlorhexidine gel (2%) was used as auxiliary chemical substance during root canal preparation. Longitudinal grooves were carved on the free surfaces of the roots, providing two halves of each root and resulting in 30 samples per group. Each group was randomly divided into three subgroups (n = 10), and substantivity was evaluated after 48 h, 7 days, and 30 days of incubation. The amount of CHX (in mg/mL) was measured through reverse-phase high-performance liquid chromatography. Statistical analysis was performed by analysis of variance and the Tukey test for post hoc comparisons (α = 0.05)., Results: The manual did not show a statistical significant difference with rotary instrumentation (P > 0.05), but higher CHX substantivity was recorded in all periods of observation when compared to reciprocating instrumentation (P < 0.05)., Conclusions: The CHX substantivity on human dentine is lowest when using reciprocating compared to manual and rotary instrumentation., Clinical Significance: Using chemical analysis, this study showed that a manual and rotary multi-instrument system results in greater chlorhexidine substantivity on human dentin than a reciprocating single-instrument system.

Introduction: The purpose of this study was to evaluate the efficiencies of different irrigation protocols in the removal of triple antibiotic paste (TAP) from root canals., Materials and Methods: A total of 127 extracted human maxillary incisor teeth were prepared. Then, root-end resection of 3 mm was accomplished to simulate immature apex model. The root canals were filled with TAP, after 21 days, randomly divided into nine groups according to irrigation systems and solutions (n = 13). Conventional irrigation (CI) groups - Group 1: Root canal irrigation was performed with CI by Peracetic acid (PAA) solution, Group 2: Root canal irrigation was performed with CI by etidronic acid 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) + sodium hypochlorite (NaOCl) solution, Group 3: Root canal irrigation was performed with CI by ethylenediaminetetraacetic acid (EDTA)/NaOCl solutions. Vibringe system groups - Group 4: Root canal irrigation was performed with Vibringe system by PAA solution, Group 5: Root canal irrigation was performed with Vibringe system by HEBP + NaOCl solution, Group 6: Root canal irrigation was performed with Vibringe system by EDTA/NaOCl solution. EndoVac system groups - Group 7: Root canal irrigation was performed with EndoVac system by PAA solution, Group 8: Root canal irrigation was performed with EndoVac system by HEBP + NaOCl solution, Group 9: Root canal irrigation was performed with EndoVac system by EDTA/NaOCl solution. Control Group: (n = 0). Samples were sectioned vertically, and the amount of remaining medicament was scored for each root half and data were statistically analyzed., Results: Among the irrigation systems, CI groups showed the highest scores at both apical and coronal parts (P < 0.05). In comparisons among the solutions, at the apical part, PAA groups showed the highest scores (P < 0.05). At the coronal part, EDTA + NaOCl groups showed the lowest score values (P < 0.05)., Conclusion: The use of irrigation systems improved the removal of TAP from the simulated immature root canals. Also, as an irrigation solution EDTA gives more promising results than PAA and HEBP solutions., Competing Interests: There are no conflicts of interest.

Introduction: This article reports for the first time the effects of multiple additives (polyethylene glycol 400, Triton X-100, benzalkonium chloride, and ethyl formate) on the surface tension, pH, and viscosity of 5.25% sodium hypochlorite (NaOCl) irrigant solution. Advanced statistical approaches based on unsupervised multivariate analysis (cluster analysis and principal component analysis) were used to quantify the variability of the physicochemical properties of the modified NaOCl solution for the first time in dentistry., Methods: Solutions of 5.25% NaOCl were modified with multiple additives in various concentrations, physicochemical parameters were measured at 22°C and 37°C, and the results were statistically analyzed to group the solutions and reveal the effects of additives., Results: Cluster analysis and principal component analysis revealed that pH and surface tension were the significant parameters (P < .05) for grouping the modified solutions. Four principal components, accounting for 90.6% of the total variance, were associated with flow characteristics (37.3%) determined by polyethylene glycol; the wetting property (22.5% and 10.5%), which was dependent on cationic and nonionic surfactant; and the antimicrobial effect (20.3%) influenced by ethyl formate. Varimax rotation of the principal components showed that the cationic surfactant (benzalkonium chloride) had significantly decreased surface tension compared with the nonionic surfactant (Triton-X). Although ethyl formate was introduced as an odor modifier, it had a significant effect on pH decrease and the occurrence of effervescence with O 2 and hypochlorous acid release., Conclusions: The statistical results revealed that the 5.25% NaOCl irrigant solution should be modified with a mixture of 0.1% benzalkonium chloride, 1% ethyl formate, and 7% polyethylene glycol for obtaining a low pH and low surface tension., (Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objectives To determine the concentration of calcium, iron, manganese and zinc ions after the application of chelator to Enterococcus faecalis biofilms. Material and Methods Fifty bovine maxillary central incisors were prepared and inoculated with E. faecalis for 60 days. The following were used as irrigation solutions: 17% EDTA (pH 3, 7 and 10), 2.5% sodium hypochlorite (NaOCl) combined with 17% EDTA (pH 3, 7 and 10), distilled water (pH 3, 7 and 10), and 2.5% NaOCl. Each solution was kept in the root canal for five minutes. Fifteen uncontaminated root canals were irrigated with 17% EDTA (pH 3, 7 and 10). Six teeth were used as bacterial control. The number of calcium, iron, manganese and zinc ions was determined using flame atomic absorption spectrometry. Mean ± standard deviation (SD) values were used for descriptive statistics. Results Calcium chelation using 17% EDTA at pH 7 was higher than at pH 3 and 10, regardless of whether bacterial biofilm was present. The highest concentration of iron occurred at pH 3 in the presence of bacterial biofilm. The highest concentration of manganese found was 2.5% NaOCl and 17% EDTA at pH 7 in the presence of bacterial biofilm. Zinc levels were not detectable. Conclusions The pH of chelating agents affected the removal of calcium, iron, and manganese ions. The concentration of iron ions in root canals with bacterial biofilm was higher after the use of 17% EDTA at pH 3 than after the use of the other solutions at all pH levels.

The aim of this study was to compare the efficacy of passive ultrasonic irrigation and EasyClean for removing residual filling material in retreatment. Twenty-two maxillary lateral incisors with apical curvature were instrumented with ProTaper files and filled with Endofill using the lateral compactation technique. Removal of filling material was performed with Reciproc, Mtwo and ProDesign Logic 50/.01 files. The teeth were inserted in a silicone mould, which was placed in a metal muffle, and split to visualize the residual filling material. The samples were divided into two groups (n = 11) according to the irrigation protocol: Passive ultrasonic irrigation (PUI group) with 3 activations of 20 seconds and EasyClean (Easy Equipamentos Odontológicos, Belo Horizonte, Brazil) (EC group) used in continuous rotation with 3 activations of 20 seconds, both using NaOCl and EDTA. Environmental scanning electron microscopic images of the apical, middle, and cervical thirds were taken before and after the irrigant activation. The Kappa test was used to determine interexaminer agreement. Statistical analysis was performed using Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests (p < 0.05). PUI and EC improved the removal of remnant filling material in all root canal thirds (p < 0.05). PUI and EC presented similar performance in the final step of retreatment (p > 0.05). No significant difference was observed in the removal of filling material in the apical, middle, and cervical thirds in both groups (p > 0.05). EasyClean in continuous rotary motion is useful in retreatment and was shown to be as effective as ultrasonic activation in the removal of remnant filling material.

The aim of this study was to compare two irrigation techniques and four devices for endodontic sealer placement into the dentinal tubules. Ninety-nine single-rooted human teeth were instrumented and allocated to either the control (CO) (n=11) or experimental groups according to the irrigation method: syringe and NaveTip needle (NT) (n=44), and EndoActivator (EA) (n=44). These groups were subdivided according to sealer placement into K-File (KF), lentulo spiral (LS), Easy Clean (EC), and EndoActivator (EA) subgroups. Moreover, the distances of 5 mm and 2 mm from the apex were analyzed. The teeth were obturated with AH Plus and GuttaCore X3. Analyses were performed by scanning electron microscopy associated to cathodoluminescence. The percentage and maximum depth of sealer penetration were measured. Data were evaluated by three-way analysis of variance (ANOVA) and Games-Howell test (p<0.05). EA was superior to NT in percentage of sealer penetration. EC was significantly superior to EA (subgroup) for sealer penetration, and both improved the percentage of sealer penetration when compared to LS. Better sealer penetration was observed at the distance of 5 mm from the apex. Sealer penetration into the dentinal tubules was significantly improved by sonic irrigant activation.

Introduction: The therapeutic effects of sodium hypochlorite (NaOCl) solutions are dependent on the levels of free available chlorine (FAC). Mixing these solutions with irrigants can result in significant reductions in FAC. Although the effect of some irrigants on FAC is known, the effect of other commonly used irrigants is not. Thus, the therapeutic ramifications of the concurrent use of these on the efficiency of NaOCl solutions is not known., Methods: Aliquots of 5.2% (w/v) NaOCl solutions were admixed in proportions of 90:10, 80:20, and 50:50 with the following irrigants: octenidine dihydrochloride (OCT); SmearOFF (Vista Dental Products, Racine, WI), 17% EDTA; and 0.2%, 2%, and 5% chlorhexidine (CHX) solutions. Changes in FAC were measured by iodometric titration. Statistical differences between means were determined using a post hoc Tukey analysis test after an analysis of variance., Results: OCT appeared not to affect FAC and was significantly different than all other irrigants, except for 90:10 and 80:20 mixtures of low concentration (0.2%) CHX. CHX solutions showed a marked concentration- and mixture proportion-dependent detrimental effect on FAC. The reduction of FAC between different concentrations of CHX was statistically significant in 80:20 and 50:50 proportions, with 50:50 mixtures of 5% CHX having the greatest influence. Mixtures containing even small proportions of SmearOFF or EDTA exhibited significant losses in FAC., Conclusions: OCT has little effect on FAC and can be used concurrently with NaOCl solutions. Higher concentrations of CHX significantly affect FAC. Their combined use with NaOCl solutions should be avoided. EDTA and SmearOFF should not be mixed with NaOCl solutions., (Copyright © 2017 American Association of Endodontists. All rights reserved.)

Aim: To compare the efficacy of the XP-endo finisher file (XP) (FKG Dentaire, La Chaux de Fonds, Switzerland) to that of passive ultrasonic irrigation (PUI) and conventional syringe and needle irrigation (SNI) in the removal of calcium hydroxide paste from an artificial standardized groove in the apical third of root canals., Methodology: The root canals of 68 mandibular incisors with single oval canals were prepared using Mtwo instruments (VDW GmbH, Munich, Germany) up to size 40, .04 taper. Each tooth was split longitudinally, and in one half of the root, a standardized groove was prepared in the apical part of the specimen. The grooves were filled with Ca(OH) 2 , and the root halves were reassembled. The roots were randomly divided into two control groups (n = 4) and three experimental groups (n = 20) according to the Ca(OH) 2 methods used: XP, PUI and SNI. The amount of remaining medicament was evaluated under X25 magnification using a 4-grade scoring system. Kappa values were calculated for intra- and interobserver agreement evaluation. The differences in the Ca(OH) 2 scores amongst the different groups were analysed using the Kruskal-Wallis test., Results: None of the tested methods could completely clean the Ca(OH) 2 from the artificial standardized groove in the apical third of the root canals. XP and PUI removed significantly more Ca(OH) 2 than SNI (P < 0.001), with no significant differences between them (P = 0.238)., Conclusions: XP and PUI were more effective in removing Ca(OH) 2 from artificial standardized grooves in the apical third of root canals than SNI., (© 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Aim: To investigate the effect of irrigation on the surface roughness and fatigue resistance of HyFlex and M3 controlled memory (CM) wire nickel-titanium instruments., Methodology: Two new files of each brand were analysed by atomic force microscopy (AFM). Then, the instruments were dynamically immersed in either 5.25% sodium hypochlorite (NaOCl) or 17% ethylene diamine tetraacetic acid (EDTA) solution for 10 min, followed by AFM analysis. The roughness average (Ra) and root mean square (RMS) values were analysed statistically using an independent sample t-test. Then, 36 files of each brand were randomly assigned to three groups (n = 12). Group 1 (the control group) was composed of new instruments. Groups 2 and 3 were dynamically immersed in 5.25% NaOCl and 17% EDTA solutions for 10 min, respectively. The number of rotations to failure for various groups was analysed using the one-way analysis of variance software., Results: For M3 files, the Ra and RMS values significantly increased (P < 0.05) after the immersion. For the HyFlex file, the Ra and RMS values significantly increased (P < 0.05) only in EDTA, but not (P > 0.05) NaOCl. The resistance to cyclic fatigue of both HyFlex and M3 files did not significantly decrease (P > 0.05) by immersing in 5.25% NaOCl and 17% EDTA solutions., Conclusions: Except the HyFlex files immersed in NaOCl, the surface roughness of other files exposed to irrigants increased. However, a change in the surface tomography of CM wire instruments caused by contact with irrigants for 10 min did not trigger a decrease in cyclic fatigue resistance., (© 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

This study was to evaluate the effect of Epigallocatechin-3-gallate (EGCG) on the bond strength of two adhesive systems to the Sodium hypochlorite (NaOCl) treated intraradicular dentin. The roots were accepted regular root canal treatments and post space preparations, and further divided into eight groups according to the four post space pretreatments and two dentin adhesives [Single Bond 2 (SB2) and Clearfil SE Bond (CSB)] used. The push-out strength before and after thermocycling in different root region (coronal and apical), DC of the adhesive and morphologic patterns of treated post space were evaluated. NaOCl + EGCG groups showed the highest push-out strength regardless of the adhesive type, root region and time (P < 0.05). NaOCl pretreatment significantly decreased the push-out strengths and DC of CSB (P < 0.05). EGCG could improve the bonding properties of both SB2 and CSB to NaOCl treated intraradicular dentin. The effect of NaOCl on bonding of a fiber post depended on the type of the adhesive.

To compare the efficacy of various irrigants (citric acid, ethylenediaminetetraacetic acid (EDTA) and NaOCl) and techniques in removing Ca(OH) 2 in two types of curved root canal systems, simulated root canals with specific curvatures were used to investigate the effects of different irrigants and instruments on Ca(OH) 2 removal. The optimal methods were verified on extracted human teeth. Simulated root canals were assigned to one of two groups based on the irrigation solution: 10% citric acid or 2.5% NaOCl. Each group was divided into four subgroups according to the technique used to remove Ca(OH) 2 . The percentage of Ca(OH) 2 removal in different sections of root canals was calculated. On the basis of the results obtained for the simulated canals, 10% citric acid and 17% EDTA were applied to remove Ca(OH) 2 from the extracted human teeth with curved root canal systems. The teeth were scanned by micro computed tomography to calculate the percentage of Ca(OH) 2 removal in the canals. In simulated root canals, we found that 10% citric acid removed more Ca(OH) 2 than 2.5% NaOCl in the 0-1 mm group from the apex level (P<0.05). Ultrasonic and EndoActivator activation significantly removed more Ca(OH) 2 than a size 30 K file in the apical third (P<0.05). However, there were no significant differences in any sections of the canals for 10% citric acid or 17% EDTA in removing Ca(OH) 2 in extracted human teeth. We concluded that it was effective to remove residual Ca(OH) 2 using the decalcifying solution with EndoActivator or Passive Ultrasonic Irrigation in a curved root canal system. A protocol for Ca(OH) 2 removal was provided based on the conclusions of this study and the methods recommended in previous studies.

Objective: The aim of this in vitro study was to compare the various techniques for removing precipitate formed after irrigation with sodium hypochlorite (NaOCl) and chlorhexidine (CHX)., Background Data: It is still unclear whether different irrigant activation systems can effectively remove precipitate that is firmly attached to the root canal walls., Methods: Eighty-two extracted single-rooted human teeth were instrumented by using the ProTaper rotary system. The roots were irrigated with 5% NaOCl and then 2% CHX to form orange-brown precipitate on the root canal walls. The teeth were sectioned longitudinally, and the amount of precipitate on the canal walls was measured under a stereomicroscope at 15 × magnification before the root halves were reassembled. Then, conventional syringe irrigation (CSI), CanalBrush (CB), EndoActivator (EA) system, photon-induced photoacoustic streaming (PIPS), and manual instrumentation (MI) techniques were used to remove the precipitate, during which 5 mL of distilled water was used for 1 min. The amount of precipitate remaining on the canal walls was measured, and the percentage of precipitate removed was calculated. Data were analyzed by using the Kruskal-Wallis and Mann-Whitney U tests (p = 0.05)., Results: All experimental groups contained residual precipitate. The precipitate was more effectively removed in the MI group than in the other groups (p < 0.05). The CB and EA groups showed better removal than the CSI and PIPS groups (p < 0.05), and there were no significant differences in removal between these latter two groups (p > 0.05)., Conclusions: None of the techniques used was able to completely remove the orange-brown precipitate from the root canal surfaces.

Purpose: To evaluate the influence of irrigation protocols and drying procedures on the bond strength of two methacrylate-based sealers to dentin and the associated failure pattern using scanning electron microscopy (SEM)., Materials and Methods: Fifty single-rooted human teeth were prepared with an irrigation protocol using either 5.25% sodium hypochlorite (NaOCl) or 2% chlorhexidine (CHX) and 17% EDTA (ethylenediaminetetraacetic acid) for smear layer removal. The following subgroups were also created based on drying of the root canal walls: paper points, the canals were blot dried with paper points with the last one appearing dry; or, ethanol, excess distilled water was removed with paper points followed by dehydration with 95% ethanol for 1 min and blotting with paper points. Each group was divided into two subgroups on the basis of the root canal sealer: EndoREZ and RealSeal SE. Bond strength was measured by the push-out test. The data were analyzed by ANOVA/Tukey HSD (α = 0.05). Failure patterns were classified as adhesive, cohesive, and mixed in the SEM analysis. The failure mode was evaluated by the chi-squared test (α = 0.05)., Results: The roots irrigated with NaOCl showed significantly lower bond strength than the roots irrigated with CHX (p < .05). RealSeal SE showed higher bond strength when compared with EndoREZ (p < .05). The highest values of bond strength were in the CHX and ethanol groups with RealSeal SE (p < .05). An increase in adhesive failure was observed in the NaOCl and EDTA group., Conclusions: The bond strength of both methacrylate-based sealers is influenced by the irrigant protocol., (© 2017 Wiley Periodicals, Inc.)

Objectives: The aim of the present study is to evaluate the possible correlation between sealer penetration into dentinal tubules and sealing ability both in presence and absence of smear layer., Materials and Methods: Fourteen maxillary central incisors were treated with 5.25 % NaOCl +10 % EDTA to remove the smear layer (SL-free group) or 5.25 % NaOCl without EDTA (SL group). Root canals were filled using #25 Thermafil Obturators with Topseal sealer labelled with 0.1 wt% rhodamine B. Sealing ability was measured as fluid filtration rate with a fluid-flow meter using water supplemented with 0.3 % calcein fluorescent dye. Specimens were sectioned, observed under confocal microscope to co-localize the presence of sealer (rhodamine B labelling) into dentinal tubules and gaps (calcein labelling) into the root canal. The depth of sealer penetration into dentinal tubules and the percentage of sealer penetration around the root canal were measured at 3, 5 and 8 mm from the apex., Results: No significant differences between groups were observed in fluid filtration rate nor in depth of calcein penetration. Sealer penetration depth and percentage into dentinal tubules were not significantly different between groups, except at 8-mm level in absence of smear layer., Conclusion: Sealer penetration at 3- and 5-mm levels was not influenced by smear layer while it was significantly reduced at 8-mm level. Fluid filtration rate was not correlated either with depth of calcein penetration nor with sealer penetration into dentinal tubules., Clinical Relevance: The sealing ability of Topseal sealer is not affected by presence or absence of smear layer.

Objective: The aim of this study was to investigate the ability of laser-activated irrigation (LAI), XP-endo Finisher, CanalBrush, Vibringe, passive ultrasonic irrigation (PUI), and conventional syringe irrigation systems on the removal of calcium hydroxide (CH) from simulated root canal irregularities., Material and Methods: The root canals of one hundred and five extracted single-rooted teeth were instrumented using Reciproc rotary files up to size R40. The teeth were split longitudinally. Two of the three standard grooves were created in the coronal and apical section of one segment, and another in the middle part of the second segment. The standardized grooves were filled with CH and the root halves were reassembled. After 14 days, the specimens were randomly divided into 7 experimental groups (n=15/group). CH was removed as follows: Group 1: beveled needle irrigation; Group 2: double side-vented needle irrigation; Group 3: CanalBrush; Group 4: XP-endo Finisher; Group 5: Vibringe; Group 6: PUI; Group 7: LAI. The amount of remaining CH in the grooves was scored under a stereomicroscope at 20× magnification. Statistical evaluation was performed using Kruskal-Wallis and Bonferroni-Correction Mann-Whitney U tests., Results: Groups 1 and 2 were the least efficient in eliminating CH from the grooves. Groups 6 and 7 eliminated more CH than the other protocols; however, no significant differences were found between these two groups (P>.05)., Conclusions: Nevertheless, none of the investigated protocols were able to completely remove all CH from all three root regions. LAI and PUI showed less residual CH than the other protocols from artificial grooves.

Objectives: This study evaluated the effect of sodium hypochlorite (NaOCl) irrigation with or without surfactants on the bond strength of an epoxy-based sealer to the root canal dentin., Materials and Methods: Eighty decoronated single-rooted human mandibular premolars were instrumented using the rotary system. The roots were subsequently rinsed with 5 ml 17 % EDTA for 1 min and then randomly divided into 3 test groups (n = 20) and 1 control group (n = 20) according to the type of irrigation with experimental 5 % NaOCl (Wizard, RehberKimya, Istanbul, Turkey) solutions: Group 1: NaOCl-0.1 % benzalkonium chloride; Group 2: NaOCl-0.1 % Tween 80; Group 3: NaOCl-0.1 % Triton X-100; control group: NaOCl without any surfactants. Five samples from each group were prepared for scanning electron microscopy to examine the surface of root canal dentin. The 15 samples remaining in each group were obturated with gutta-percha and AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany) using the cold lateral compaction technique. A push-out test was used to measure the bond strength between the sealer and root canal dentin. Data were analyzed using two-way analysis of variance and Tukey's post hoc tests (P = 0.05)., Results: The NaOCl-0.1 % Triton X-100 group demonstrated the highest mean bond-strength values in all root thirds among the groups (P < 0.05). However, the bond strength of the sealer in the NaOCl-0.1 % benzalkonium chloride and NaOCl-0.1 % Tween 80 groups did not differ from that in the control group (P > 0.05). Additionally, the bond-strength values decreased in the corono-apical direction for all groups (P < 0.05)., Conclusions: NaOCl solution with Triton X-100 can provide higher bond strength of the epoxy resin-based sealer to root dentin compared to NaOCl solution wiithout any surfactant., Clinical Relevance: The bond strength of sealer to dentin can be improved by the addition of the surfactants to NaOCl solution.

Introduction: Tricalcium silicate (TCS)-based materials are used in endodontics because they are hydraulic and interact with blood, tissue fluids, and phosphate-based root canal irrigants, resulting in biomineralization. Newer-generation materials are biphasic; calcium phosphate is added to the TCS; thus, the material has 2 cementitious phases. The effect of this addition is not known; thus, the aim of this study was to characterize biphasic cements and assess cellular proliferation and expression., Methods: TCS cement mixed with calcium phosphate monobasic or hydroxyapatite in 1:1 proportion was prepared. The powders and the mixed cements soaked in Hank's balanced salt solution for 28 days were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy, and X-ray diffraction analysis. Ion leaching was investigated using inductively coupled plasma mass spectroscopy. Cellular interaction with material leachate was investigated by exposing human primary osteoblasts to the leachate from the cements. Cell growth and proliferation were determined using methyltetrazolium assay and SEM., Results: The addition of a calcium phosphate phase to tricalcium silicate changed the material hydration with a reduction in pH and calcium ion release in the leachate when calcium phosphate monobasic was added. No crystalline calcium hydroxide was formed for both biphasic materials. The biphasic cements exhibited a reduction in cell growth and proliferation. SEM of the materials showed heavy carbonation of the material surface caused by processing for microscopy., Conclusions: The addition of a second cementitious phase results in modification of the hydration characteristics of TCS cement with deterioration of material and biocompatibility properties., (Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objectives: The purpose of the present study was to determine the dislodgement resistance of AH Plus, MTA Fillapex, and Total Fill BC sealer to root canal dentin walls following placement of calcium hydroxide (CH) or double antibiotic paste (DAP) medicaments., Materials and Methods: Root canals of 90 single-rooted human mandibular premolar teeth were instrumented with Reciproc rotary instruments to a size R50. The teeth were randomly divided into two experimental groups: those receiving an intracanal medicament with either CH or DAP and a control group (n = 30). After 3 weeks, the medicaments were removed by irrigation with 5 mL of 2.5 % NaOCl, 5 mL 17 % EDTA, and 5 mL distilled water under sonic agitation. Each group was then subdivided into three subgroups (n = 10), and the canals were filled with either AH Plus, MTA Fillapex, or Total Fill BC sealer. After 1 week, a push-out test was applied to the specimens and the results were analyzed using one-way analysis of variance (ANOVA) and post hoc Tamhane's tests., Results: Regardless of the type of intracanal medicament used, Total Fill BC Sealer and MTA Fillapex showed the highest and lowest bond strength, respectively (P < 0.05). The use or absence of medicaments did not significantly affect the dislodgment resistance of root canal fillings (P > 0.05). Prior CH placement improved dislodgement resistance of all sealers without statistical difference (P > 0.05). Adhesive failure between core and sealer was the most frequent failure mode., Conclusions: Prior application of CH or DAP did not significantly affect the adhesion of the AH Plus, MTA Fillapex, and Total Fill BC Sealers., Clinical Relevance: There is a little information about the influence of antibiotic medicaments on the bond strength of root canal sealer. These findings suggest that the use of DAP does not affect the adhesion strength of AH Plus, MTA Fillapex, and Total Fill BC Sealers.

This study evaluates the influence of root dentin treatment with NaOCl alone and combined with EDTA, with and without ultrasound activation, on the push-out bond strength (BS) of fiber-reinforced posts in weakened roots, cemented with RelyX or Panavia. The root canals of 42 maxillary canines were instrumented with Reciproc and 2.5% NaOCl. In the coronal 12mm of all canals, experimental weakening of the roots was produced by reducing dentin thickness with 2.44mm diameter diamond burs. The roots were assigned to 3 groups (n = 14) according to root dentin treatment: 2.5% NaOCl; 2.5% NaOCl + 17% EDTA; and 2.5% NaOCl + 17% EDTA, with solutions agitated using passive ultrasonic irrigation. After cementation of the fiber-reinforced posts the roots were divided in thirds. The first slice of each third was used for the push-out BS test, the second slice for confocal laser scanning microscopy and dentin microhardness (Knoop) analysis. Data were analysed by a two-way ANOVA and Tukey test (a = 0.05). NaOCl + EDTA provided highest BS values than NaOCl (p < 0.0001). Specimens cemented with Panavia presented significantly higher BS than those with RelyX in the three root thirds (p < 0.0001). The highest BS values occurred in the cervical third (p < 0.001). Ultrasound-activated NaOCl + EDTA promoted the greatest reduction in dentin microhardness, followed by NaOCl/EDTA and NaOCl. Ultrasonic activation of NaOCl and EDTA reduced root dentin microhardness, but did not improve the push-out BS of resin-based cements. Panavia presented higher BS than RelyX. RelyX was not influenced by the root dentin treatment protocols.

Objectives: The purpose of this study was to investigate, in vitro, the retaining of 2 % CHX gel, 2 % CHX liquid and QMix (an endodontic irrigant) within a root canal for 24 h, 30, 90, and 120 days by chemical analysis., Methods: Eighty extracted human teeth were used for this study. The samples were divided into four groups (G1-G4), according to the chemical auxiliary substance used to perform the instrumentation: G1 (control): distilled water, G2: 2 % CHX gel, G3: 2 % CHX liquid, and G4: QMix. The roots were prepared up to the instrument #45 by serial instrumentation. Longitudinal grooves were carved on the free surfaces of the roots, providing 2 halves of each root and resulting in 40 samples per group. Each group was randomly divided into four subgroups (n = 10), and substantivity was evaluated after 24 h, 30, 90, and 120 days. The amount of 2 % CHX gel, 2 % CHX liquid, and QMix (in micrograms) was measured through reverse-phase high-performance liquid chromatography. Statistical analysis was performed by ANOVA and Games-Howell test for post-hoc comparisons (α = 0.05)., Results: CHX gel, CHX liquid, and QMix were retained in dentin up to 120 days. Significantly less substantivity was observed for QMix, irrespective of the period of time. Statistically significant higher values were observed for CHX gel after 24 h, while no differences were noted between CHX gel and CHX liquid after 30, 90, and 120 days of evaluation (p < 0.05)., Conclusions: Two percent CHX (gel and liquid) and QMix are retained in root canal dentin for up to 120 days., Clinical Relevance: This study proposes an alternative of auxiliary chemical substance to be used during the chemo-mechanical preparation.

The purpose of this study was to assess the efficacy of the XP-endo Finisher (FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) file on debris and smear layer removal in curved root canals in comparison to different irrigation regimens. Seventy-five freshly extracted human mandibular molar teeth with mesial root curved more than 20° were used in this study. The mesial root canals were mechanically prepared using the BT-Race rotary system (FKG Dentaire) and divided into five groups (n = 15) according to the following irrigation techniques: positive control, non-agitated, File agitation, XP-endo Finisher, and EndoActivator (Dentsply Tulsa Dental Specialities, Tulsa, OK, USA). Root canals were split longitudinally and evaluated by scanning electron microscopy. Five-grade scoring system was used to assess the presence of debris and smear layer at the coronal, middle, and apical regions. The XP-endo Finisher and EndoActivator groups revealed significantly lower debris and smear layer scores than the other groups at the coronal, middle, and apical regions (P < 0.05). There was no significant difference between XP-endo Finisher and EndoActivator groups (P > 0.05). The apical region had higher debris and smear layer scores compared with the coronal regions in all groups (P < 0.05), except for the positive control group; there was no significant difference between the three regions of the root canal (P > 0.05). Irrigation of curved root canals using XP-endo Finisher and EndoActivator methods appears to be more effective on debris and smear layer removal than the other tested groups.

Introduction: A clinically useful all-in-one endodontic irrigant with combined proteolytic and decalcifying properties is still elusive. In this study, the chemical effects of dissolving the tetrasodium salts of 1-hydroxyethane 1,1-diphosphonic acid (Na 4 HEDP) or Na 4 EDTA directly in sodium hypochlorite (NaOCl) irrigants in polypropylene syringes were assessed during the course of 1 hour., Methods: The solubility of the salts in water was determined. Their compatibility with 1% and 5% NaOCl was measured by iodometric titration and in a calcium complexation experiment by using a Ca 2+ -selective electrode., Results: The salts dissolved within 1 minute. The dissolution maximum of Na 4 HEDP in water (wt/total wt) was 44.6% ± 1.6%. The corresponding dissolution maximum of Na 4 EDTA was 38.2% ± 0.8%. Na 4 HEDP at 18% in 5% NaOCl caused a mere loss of 16% of the initially available chlorine during 1 hour. In contrast, a corresponding mixture between NaOCl and the Na 4 EDTA salt caused 95% reduction in available chlorine after 1 minute. Mixtures of 3% Na 4 EDTA with 1% NaOCl were more stable, but only for 30 minutes. Na 4 HEDP lost 24% of its calcium complexation capacity after 60 minutes. The corresponding loss for Na 4 EDTA was 34%., Conclusions: The compatibility and solubility of particulate Na 4 HEDP with/in NaOCl solutions are such that these components can be mixed and used for up to 1 hour. In contrast, short-term compatibility of the Na 4 EDTA salt with NaOCl solutions was considerably lower, decreasing at higher concentrations of either compound. Especially for Na 4 HEDP but also for Na 4 EDTA, the NaOCl had little effect on calcium complexation., (Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objectives: To assess tooth crown's color after intracanal treatment with triple antibiotic paste (TAP) or calcium hydroxide (CH); cervical sealing with glass ionomer cement (GIC) or mineral trioxide aggregate (MTA); and bleaching with carbamide peroxide., Material and Methods: After pulp removal and color spectrophotometer measurement, 50 bovine incisors were divided into 4 experimental groups and one control (untreated). Experiments were performed in phases (Ph). Ph1: TAP (ciprofloxacin, metronidazole, minocycline), TAPM (ciprofloxacin, metronidazole, amoxicillin), DAP (ciprofloxacin, metronidazole), or CH treatment groups. After 1 and 3 days (d); 1, 2, 3 weeks (w); and 1, 2, 3 and 4 months (m), color was measured and medications were removed. Ph2: GIC or MTA cervical sealing, each using half of the specimens from each group. Color was assessed after 1d, 3d; 1w, 2w, 3w; 1m and 2m. Ph3: Two bleaching sessions, each followed by color measurement. Data were analyzed with ANOVA and post-hoc Holm-Sidak method., Results: Ph1: Specimens of TAP group presented higher color alteration (ΔE) mean than those of TAPM group. No significant difference was found among TAP or TAPM and CH, DAP or Control groups. Ph2: cervical sealing materials showed no influence on color alteration. Ph3: Different ΔE means (from different groups), prior to bleaching, became equivalent after one bleaching session., Conclusions: TAP induces higher color alteration than TAPM; color alteration increases over time; cervical sealing material has no influence on color alteration; and, dental bleaching was able to recover, at least partially, the tooth crown's color.

Aim: The aim of this study was to determine the following: (i) the quantity of free chlorine in mixtures of equal proportions of sodium hypochlorite (NaOCl) with trisodium ethylenediaminetetraacetic acid (EDTAHNa 3 ) and alkaline tetrasodium ethylenediaminetetraacetic acid (EDTANa 4 ); (ii) organic matter dissolution; and (iii) the time necessary to remove the smear layer by these irrigants alone and when mixed., Methodology: The solutions were mixed in a 1 : 1 ratio and then iodometrically titrated over time to determine the quantity of free available chlorine. The capability of organic matter dissolution by the solutions alone and the mixtures of irrigants was analysed by weighing bovine muscle tissue specimens before and after submission to the following groups (n = 10): G1 - 0.9% saline solution (control), G2 - 2.5% NaOCl, G3 - 17% EDTAHNa 3 , G4 - 10% EDTANa 4 , G5 - 20% EDTANa 4 , G6 - 5% NaOCl + 17% EDTAHNa 3 , G7 - 5% NaOCl + 10% EDTANa 4 and G8 - 5% NaOCl + 20% EDTANa 4 . The times necessary for smear layer removal were determinated on discs of bovine dentine with a standardized smear layer produced with SiC papers using a scanning electron microscope that did not require the samples to be sputter coated. The dentine discs were submitted to the same experimental groups previously described (n = 10) over several time periods, and the photomicrographs acquired were scored for the presence of smear layer. The parametric data of tissue dissolution were analysed using two-way anova and one-way anova with Tukey's post hoc tests (α < 0.05), whilst nonparametric data of smear layer removal were analysed by Friedman test (α < 0.05) and the Kruskal-Wallis test with Dunn's post hoc (α < 0.05)., Results: EDTAHNa 3 caused an almost complete and immediate loss of free available chlorine from NaOCl, whilst EDTANa 4 promoted a slow and concentrat-ion-dependent decline. The organic matter was not dissolved in the control group, EDTA groups or the mixture of NaOCl + 17% EDTAHNa 3 group (P > 0.05). NaOCl alone and the associations of NaOCl + EDTANa 4 dissolved tissue at all periods analysed (P < 0.05). The smear layer was not removed in the control and NaOCl groups (P > 0.05). The smear layer was removed at 1 min in the NaOCl + 17% EDTAHNa 3 group (P < 0.05); 2 min in 17% EDTAHNa 3 group (P < 0.05); and 5 min in 10% EDTANa 4 , 20% EDTANa 4 , 5% NaOCl + 10% EDTANa 4 and 5% NaOCl + 20% EDTANa 4 groups (P < 0.05)., Conclusions: Alkaline EDTANa 4 was slower in removing the smear layer than EDTAHNa 3 , but when mixed with NaOCl during biomechanical canal preparation promoted organic matter dissolution and smear layer removal simultaneously. However, the mixing of NaOCl and EDTANa 4 should be performed immediately before use to prevent the reduction of free available chlorine., (© 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Objective: The tissue-dissolving and bactericidal activity of sodium hypochlorite (NaOCl) can be increased by warming the NaOCl solution without concurrently increasing its toxicity. The present study was set up to determine if and to what extent a heated liquid reaches the apical region., Method and Materials: A temperature sensor was introduced from the apical aspect into a human canine 22 mm in length prepared to size 40.04. At 37°C in the incubator the canal was irrigated with water 10 times each at temperatures of 10°C, 21°C, 45°C, 60°C, and 37°C (control group). The apical temperature curve was recorded with a one-second resolution from the time the irrigation started until at least 2 minutes after its end., Results: None of the measurements yielded the same temperature in the apical region as that of the coronally introduced liquid. At 60°C, a maximum value of 52.2°C ± 1.39°C, and at 10°C, a minimum value of 16.09°C ± 0.39°C, was achieved apically. At 1 minute after the end of active rinse cycle, the temperature at the apical probe differed only 4.8°C to 0.9°C ± 1.41°C from the initial value (about 37°C). Only with the cold 10°C solution was the temperature difference higher, at 7.5°C ± 2.14°C., Conclusion: The benefit of heating irrigants accrues primarily during the period of active rinsing; immediately after the end of the rinsing cycle, body temperature is reached again. A positive aspect to be noted is that an irrigant stored at room temperature is quickly warmed to 37°C in the root canal by the temperature of the body.

Objective: This study evaluated the effect of different filling pastes and cleaning agents on the root dentin of primary teeth using Fourier-transformed Raman spectroscopy (FT-Raman), micro energy-dispersive X-ray fluorescence (µ-EDXRF) and scanning electron microscopic (SEM) analysis., Material and Methods: Eighty roots of primary teeth were endodontically prepared and distributed into 4 groups and filled according to the following filling pastes: Control-no filling (CP), Calen®+zinc oxide (CZ), Calcipex II® (CII), Vitapex® (V). After seven days, filling paste groups were distributed to 4 subgroups according to cleaning agents (n=5): Control-no cleaning (C), Ethanol (E), Tergenform® (T), 35% Phosphoric acid (PA). Then, the roots were sectioned and the dentin root sections were internally evaluated by FT-Raman, µ-EDXRF and SEM. Data was submitted to two-way ANOVA and Tukey tests (α=0.05)., Results: Regarding filling pastes, there was no significant difference in organic content. CP provided the lowest calcium values and, calcium/phosphoric ratio (Ca/P), and the highest phosphoric values. For cleaning agents there was no difference in organic content when compared to the C; however, T showed significantly higher calcium and Ca/P than PA. All groups showed similar results for phosphorus. The dentin smear layer was present after use of the cleaning agents, except PA., Conclusion: The filling pastes changed the inorganic content, however they did not change the organic content. Cleaning agents did not alter the inorganic and organic content. PA cleaned and opened dentin tubules.

Introduction: Octenisept (OCT; Schülke & Mayr, Nordersdedt, Germany), an antimicrobial, antibiofilm agent and a promising root canal irrigant, can be potentially combined with sodium hypochlorite (NaOCl) during endodontic treatment. The aim of this study was first to identify the precipitate formed on the interaction between OCT and NaOCl and secondly to compare its effect on dentinal tubules with that of precipitate formed on combining chlorhexidine (CHX) and NaOCl., Methods: This observational study was conducted in 3 stages. Initially, the color changes and precipitate formation were assessed when the test solution 0.1% OCT and 5.2% NaOCl were mixed. Color changes were compared with those observed when 2% CHX was mixed with 5.2% NaOCl. The residue obtained on combining OCT and NaOCl was subjected to proton nuclear magnetic resonance ( 1 H NMR) and mass spectrometric (MS) analysis. In the final stage, dentinal surfaces irrigated alternatively with OCT and NaOCl were compared using scanning electron microscopy (SEM) with the dentinal surface irrigated with CHX and NaOCl., Results: The OCT-NaOCl mixture changed in color from initial milky white to transparent over time, whereas the CHX-NaOCl mixture showed an immediate peach-brown discoloration. 1 H NMR and MS analysis established that the whitish precipitate obtained on combining OCT and NaOCl solutions correlated with the structure of phenoxyethanol (PE). SEM revealed dense precipitate occluding the dentinal tubules with the CHX and NaOCl group, whereas the precipitate was sparse and partially occluded in the OCT and NaOCl group., Conclusions: The whitish precipitate formed with the OCT-NaOCl mixture was identified as PE, a compound already present in OCT, and it partly occluded the dentinal tubules., (Copyright © 2016 American Association of Endodontists. All rights reserved.)

Objectives: The aim was to evaluate ex vivo apical debris extrusion associated with WaveOne and Self-Adjusting File instruments when used in oval canals., Methods: Twenty-four extracted human mandibular premolars with oval-shaped canals were assigned in two equal groups. Following coronal cavity preparation, a glide path was created. Group A was subjected to canal preparation using a WaveOne primary file, which was used along with syringe and needle irrigation and 10 mL of 2.4 % NaOCl solution, followed by flushing with 10 mL of 17 % EDTA solution, activation with EndoActivator for 1 min and final flushing with 10 mL of 2.4 % NaOCl solution, and activation for 30 s. Group B, the SAF system was used with continuous simultaneous irrigation, provided by the system's pump. The irrigant was supplied at 5 mL/min, alternating every minute between 2.4 % NaOCl solution and 17 % EDTA solution, over a total of 4 min followed by final flushing with 10 mL of 2.4 % NaOCl solution. Extruded apical debris from each root canal was collected into a preweighed glass vial and dried. The mean weight of the debris from each group was assessed and analyzed statistically. Both systems resulted in apical debris extrusion., Results: The WaveOne system was associated with a statistically significant greater mean mass of apically extruded debris (2.18 ± 0.44 mg) than the SAF system (0.49 ± 0.33 mg, permutation-based Wilcoxon test, p < 0.001)., Conclusion: Both WaveOne and the SAF systems were associated with apical debris extrusion. The amount of debris extruded by the WaveOne system was 4.4 times greater than that extruded by the SAF system., Clinical Relevance: The results of the present ex vivo comparative study cannot be directly applied to the clinical situation. Difference between both groups remains completely unclear; maybe the amount of extrusion is harmless in both groups or similarly deleterious for the periradicular tissues in both groups or may be dose-related to the amount of the extruded material.

Objectives: The aim of this study was to evaluate the efficacy of sonic and ultrasonic activation of epoxy-amine resin-based root canal sealer (2Seal; VDW GmbH, München, Germany) on penetration of the sealer into lateral canals compared to non-activated filling., Materials and Methods: Thirty-six single-rooted human anterior teeth were decoronated and prepared, using the ProTaper rotary system (Dentsply Maillefer, Ballaigues, Switzerland) to F4. After the completion of the clearing procedures, lateral canals were created at 2, 4, and 6 mm from the working length. The specimens were randomly divided into a control group (non-activated sealer application) and two experimental groups that received a sealer application with either sonic or ultrasonic activation. The root canals were filled using cold lateral compaction and images were obtained from each lateral canals at 40× magnification using a stereomicroscope. The sealer penetration was evaluated using a four-grade scoring system. The data were evaluated statistically using the Kruskal-Wallis and Mann-Whitney U tests with a 95 % confidence level (P = 0.05)., Results: The ultrasonic activation resulted in a better sealer penetration compared with the non-activated and sonically activated groups (P < 0.001). Sonic activation also resulted in better sealer penetration compared to the non-activated group (P < 0.001)., Conclusions: The use of the ultrasonic activation of an epoxy-amine resin-based sealer promoted greater sealer penetration into the lateral canals. Sonic activation was not effective as ultrasonic activation, but was more effective than the non-activated group., Clinical Relevance: The ultrasonic activation of an epoxy-amine resin-based sealer could be beneficial in filling procedures.

Objective: The aim of this study was to investigate the effectiveness of conventional syringe irrigations, passive ultrasonic irrigation (PUI), Vibringe, CanalBrush, XP-endo Finisher, and laser-activated irrigation (LAI) systems in removing double antibiotic paste (DAP) from root canals., Material and Methods: One hundred five extracted single-rooted teeth were instrumented. The roots were split longitudinally. Three standard grooves were created and covered with DAP. The roots were distributed into seven groups: Group 1, beveled needle irrigation; Group 2, double side-vented needle irrigation; Group 3, CanalBrush; Group 4, XP-endo Finisher; Group 5, Vibringe; Group 6, PUI; Group 7, LAI. The amount of remaining DAP was scored under a stereomicroscope., Results: Group 4, Group 6, and Group 7 removed significantly more DAP than the other protocols in the coronal region. Group 7 was more efficient in the middle region; however, no significant difference was found between Group 7 and Group 6. No differences were found between groups in the apical region either, except for the comparisons between groups 7 and 2, and groups 2 and 3., Conclusions: None of the investigated protocols were able to completely remove the DAP from the grooves. The Vibringe and XP-endo Finisher systems showed results similar to those of conventional needle irrigation.

Introduction: The present study aimed to rank the bond strength to root dentin of a new injectable pozzolan-based root canal sealer, EndoSeal MTA, as compared with MTA Fillapex and AH Plus., Methods: Eighteen dentinal slices (1 ± 0.1 mm) were obtained from the middle third of 6 maxillary incisors previously selected. Three canal-like holes with 0.8 mm diameter were drilled perpendicularly on the axial surface of each slice. Then, a standardized irrigation was applied for all holes that were subsequently filled with 1 of 3 test root canal sealers. After that, slices were stored in contact with phosphate-buffered saline solution (pH 7.2) for 7 days at 37°C before the push-out assay. Friedman test and Wilcoxon signed rank test with a Bonferroni correction were used to rank the results. Significance boundary was set at α = 5%., Results: Friedman test confirmed a significant dissimilarity in push-out ranks among the tested cements (P < .01). Wilcoxon signed rank test demonstrated AH Plus had significant superior resistance to dislodgment compared with Endo Seal (P < .01) or MTA Fillapex (P < .01), whereas MTA Fillapex presented the lowest push-out values as compared with Endo Seal (P < .01) or AH Plus (P < .01)., Conclusions: EndoSeal presents satisfactory bond strength performance for application in endodontic therapy compared with MTA Fillapex, and although it displays a new alternative of injectable bio-tight root canal sealer, it is not able to improve adhesion compared with AH Plus., (Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objective: This study compared the effectiveness of Er:YAG laser-activated irrigation (PIPS), passive ultrasonic irrigation (PUI) with EndoUltra and standard needle irrigation (SNI) in the removal of calcium hydroxide [Ca(OH)2] from the mesial roots of Weine Type II mandibular molars., Material and Methods: Thirty mandibular molars were screened by µCT for the presence of mesial roots with complex intra-canal anatomy and a common apical foramen. The teeth were enlarged to a standardized 25/.06 preparation and filled with Ca(OH)2 paste. Specimens were divided into three groups (n=10) according to the technique used for Ca(OH)2 removal: PIPS, at 15 Hz and 20 mJ using a 9 mm long, 600 µm diameter tip; PUI using a 15/.02 tip; and SNI (30 Ga. side-vented needle). Equal volumes of 8.25% NaOCl and 17% EDTA were used in all groups. µCT was used to measure the initial amount of Ca(OH)2 present and to assess the residual volume of Ca(OH)2 following each irrigation protocol. Data were analyzed using Tukey HSD and Kruskal-Wallis tests (α=5%)., Results: The mean volume of Ca(OH)2 before removal was significantly higher in the coronal third than in the middle and apical third (p<0.001). Ca(OH)2 was similarly removed from the coronal and middle thirds with the three methods used (p>0.05). PIPS (median 0%; IQR: 0-0) showed significant higher Ca(OH)2 removal in the apical third than PUI (median 100%, IQR: 85-100) and SNI (median 47%; IQR: 16-72) (p<0.001)., Conclusions: PIPS laser-activation was more effective for the removal of Ca(OH)2 from mesial roots of mandibular molars with Weine Type II canal configurations than PUI with EndoUltra and SNI.

Objective: The aim of this study on human cadavers was to compare the accuracy of two electronic apex locators (EALs) Dentaport ZX (J. Morita Corporation, Tokyo, Japan) and Raypex 6 (VDW, Munich, Germany)., Materials and Methods: Twenty-two single rooted teeth of four human cadaver heads were scheduled for this study. Before the extraction, an access cavity was opened and the crown was cut to establish a stable reference point for all measurements. The working length determination was performed with Dentaport ZX and Raypex 6 in the presence or not of 5.25 % sodium hypochlorite (SH) using a k-file 10. The teeth were then extracted and the real working length (RWL) was measured under a stereomicroscope at ×30 magnification. The difference between the two working lengths was calculated: positive values indicate measurements exceeding the foramen, while negative values indicated measurements short of the foramen. The data were analyzed with a t test analysis., Results: The mean of distances was 0.33 ± 0.20 mm and 0.32 ± 0.2 mm for Dentaport ZX respectively in the presence or not of SH and 0.38 ± 0.20 mm and 0.39 ± 0.19 mm for Raypex 6. No statistical differences were found between the two devices (p > 0.05)., Conclusions: Both apex locators showed a high accuracy in the presence or not of SH., Clinical Relevance: Both electronic apex locators can be recommended for clinical use and their accuracy is not affected by SH.

In the field of endodontology, antibacterial activity of irrigants has been investigated many times. The influence of these solutions on the bonding of root canal sealers, however, has hardly been studied. The objective of this doctoral research was to determine the interactions between root canal sealers and root dentin, and to determine the influence of irrigants on these interactions. The various studies revealed that irrigants have an influence on the bonding of sealers based on epoxy resin, calcium hydroxide, silicones and calcium silicate. In the case of a sealer based on epoxy resin (AH Plus), the irrigation protocol had an influence on the bond strength (adhesion) on dentin, by means of which the seal was also improved. The results of this research produced better insights into the mechanisms at play in the adhesive properties of root canal sealers. Eventually, this might result in improved treatment outcomes of root canal treatments.

Objective: The aim of this study was to evaluate the efficiencies of different irrigation protocols and solutions in the removal of calcium hydroxide (Ca[OH]2)., Materials and Methods: Sixty-eight maxillary incisors were used. Root canals were prepared and filled with Ca(OH)2. Two control (n = 4) and six experimental groups (n = 10) were adjusted: Group 1:1% peracetic acid (PAA) + master apical file (MAF); Group 2: 17% ethylenediaminetetraacetic acid (EDTA) + MAF; Group 3: 9% 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) + MAF; Group 4: 1% PAA + ultrasonic activation (UA); Group 5: 17% EDTA + UA; Group 6: 9% HEBP + UA. The cleanliness of root canal thirds were evaluated with scanning electron microscopy. Statistical analysis were performed (α = 0.05)., Results: At coronal thirds; PAA + UA was superior to EDTA + MAF, HEBP + MAF; and PAA + MAF was superior to EDTA + MAF, HEBP + MAF (P < 0.05). At middle thirds; PAA + MAF and PAA + UA were superior to EDTA + MAF and EDTA + UA; and, PAA + UA was superior to HEBP + MAF (P < 0.05). There were no significant differences among the rest of the experimental groups (P > 0.05)., Conclusion: Complete removal of Ca(OH)2could not be achieved by none of the irrigants at all root thirds.