Effect of EDTA,sodium, and calcium hypochlorite on the inorganic component of root canal dentin: A SEM analysis

This study evaluated the influence of canal irrigation protocols with 5.25% calcium hypochlorite [Ca(OCl)₂], 5.25% sodium hypochlorite (NaOCl) and 17% EDTA solution on the inorganic component of root canal dentin. Sixty roots were randomly divided into six groups (n = 10): Saline solution (SS) (control); Saline solution (SSE) +17% EDTA; CH ? 5.25% Ca(OCl)₂; CHE ? 5.25% Ca(OCl)₂ + 17% EDTA; SH ? 5.25% NaOCl; SHE ? 5.25% NaOCl +17% EDTA. After canal irrigation, the specimens were longitudinally split and analyzed by scanning electron microscopy (SEM). Dentinal tubules were observed in transverse (middle and apical thirds) direction. The images were classified in scores, according to smear layer removal and peritubular dentin alteration, and data were analyzed by Kruskal–Wallis's test, followed by Dunn's test (α = 0.05). In the middle third, all groups with EDTA presented better removal of the smear layer with higher peritubular dentin alteration (p < .05). In the apical third, this happened only in SHE (p < .05). Ca(OCl)₂ and NaOCl exhibit similar performance to remove smear layer and alteration of the inorganic component in the middle third. In the apical third, NaOCl associated with EDTA showed better performance in smear layer removal.     

The effect of final irrigation with MTAD,QMix, and EDTA on smear layer removal and mineral content of root canal dentin

To compare the smear layer removal ability and mineral content of root canal dentine after initial irrigation with NaOCl and final irrigation with MTAD, QMix, and 17% EDTA. Forty extracted human maxillary incisors before root canal preparation and irrigation with NaOCl were randomly divided into four groups (n = 10) according to the type of final irrigants used: MTAD, QMix, 17% EDTA, and control (sterile distilled water). Scanning electron microscopy (SEM) was used to assess the presence of smear layer. SEM energy‐dispersive X‐ray spectroscopy was used to quantify dentin mineral composition in MTAD, QMix, 17% EDTA group, and in no‐treatment samples (no‐treatment group; n = 10). Among the various chelating agents, there were no significant differences in the smear layer removal in the middle and coronal thirds (p > .05). In the apical third, QMix removed significantly more smear layer than 17% EDTA (p < .05), but similarly to MTAD (p > .05). Final irrigation with MTAD resulted in a significant increase in the carbon (C) value compared to EDTA (p < .001). There was no significant difference in the mineral composition between the MTAD and the QMix group, although the values of the mineral elements were significantly altered in the MTAD group. QMix had smear layer removal capability similar to MTAD but better than EDTA in the apical third. MTAD yielded the most pronounced effect on mineral component of root dentin; however, differences were significant only for C level compared to 17% EDTA.     

Effect of passive ultrassonic instrumentation as a final irrigation protocol on debris and smear layer removal—a sem analysis

This study sought to evaluate the efficacy of passive ultrasonic irrigation (PUI) on removing the smear layer and debris from root dentin using scanning electron microscopy (SEM). Twenty‐five bovine incisors were manually prepared and divided into three groups according to the final irrigation protocol: EDTA, final irrigation with 12 mL of 17% EDTA for 3 minutes followed by 5 mL of 2.5% NaOCl; EDTA/PUI, final flush with 4 mL of 17% EDTA and PUI for 30 seconds. These procedures were repeated three times to standardize the volume of the irrigant. Control group, after preparation, the specimens were irrigated only with 17 mL of 2.5% NaOCl. The roots were fractured and analyzed using SEM. The intragroup analysis revealed that the EDTA/PUI protocol removed a higher amount of debris at the cervical third (P = 0.03). The intergroup analysis revealed that EDTA/PUI presented the lowest amount of debris at the cervical third (P = 0.007). Smear layer scores were higher in the control group compared with the EDTA and EDTA/PUI groups, but only at the cervical third (P = 0.02). None of the final irrigant protocols completely removed the smear layer and debris. EDTA/PUI only improved the removal of debris at the cervical third. Microsc. Res. Tech. 76:496–502, 2013. © 2013 Wiley Periodicals, Inc.     

Cleaning capacity of octenidine as root canal irrigant: A scanning electron microscopy study

The aim of this study was to assess the cleaning capacity of the octenidine hydrochloride (OCT) used as root canal irrigant by scanning electron microscopy (SEM) analysis. Sixty human unirradicular extracted teeth were randomly distributed in 6 groups (n = 10) according to irrigant solutions which were used during root canal preparation: G1, 0.1% OCT; G2, 2% chlorhexidine (CHX); G3, 2.5% sodium hypochlorite (NaOCl); G4, OCT + 17% ethylenediaminetetraacetic acid (EDTA); G5, 2.5% NaOCl + 17% EDTA and G6, distilled water. All specimens were instrumented with ProTaper system up to F4. Teeth were sectioned and prepared for SEM. The smear layer was evaluated using a 5‐score system and the data were analyzed by Kruskal–Wallis and Dunn (α = 0.05). In all root canal thirds there was no significant difference between OCT, CHX, NaOCl, and water groups (p > .05), and these groups showed higher smear layer values than NaOCl + EDTA and OCT + EDTA groups (p < .05). There was no significant difference between NaOCl + EDTA and OCT + EDTA groups (p > .05). It was concluded that OCT used as a single root canal irrigant presented poor cleaning capacity and could be used in association with a final irrigation with EDTA to obtain smear layer removal.     

Evaluation of 17% EDTA and 10% citric acid in smear layer removal and tubular dentin sealer penetration

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.     

Effect of final irrigation protocols on microhardness and erosion of root canal dentin

The aim of this study was to evaluate the effect of final irrigation protocols (17% EDTA, BioPure MTAD, SmearClear, and QMiX) on microhardness and erosion of root canal dentin. Fifty roots were sectioned transversely at the cement–enamel junction and each root was sectioned horizontally into 4‐mm‐thick slices. The samples were divided into five groups (n = 10) according to the final irrigation protocol: G1: distilled water (control group); G2: 17% EDTA; G3: BioPure MTAD; G4: SmearClear; and G5: QMiX. The dentin microhardness was then measured with a load of 25 g for 10 s. Initially, the reference microhardness values were obtained for the samples without any etching. The same samples were then submitted to the final irrigation protocols. A new measure was realized and the difference between before and after the procedures was the dentin microhardness reduction. In sequence, the specimens were submitted to SEM analysis to verify the dentinal erosion. The Kruskal Wallis and Dunn tests (α = 5%) were used to compare the results. The dentin microhardness decreased for all final irrigation protocols. There was no significant difference between groups 2, 3, 4, and 5 (P > 0.05), but this groups presented significant dentin microhardness reduction than G1 (P < 0.05). In G2, occurred the highest incidence of dentinal erosion (P < 0.05). 17% EDTA, BioPure MTAD, SmearClear, and QMiX promoted significant dentin microhardness reduction. Dentinal tubules erosion was promoted by 17% EDTA. Microsc. Res. Tech., 76:1079–1083, 2013. © 2013 Wiley Periodicals, Inc.     

Evaluation of different irrigation protocols concerning the formation of chemical smear layer

The aim of this work was to evaluate, by means of scanning electron microscopy (SEM) and electron dispersive spectroscopy (EDS), the different irrigation protocols concerning the formation of chemical smear layer (CSL). Fifty‐five teeth were instrumented by using distilled water (DW) as irrigant. Next, the teeth were submitted to a protocol for removal of the mechanical smear layer produced. The teeth were divided into 11 groups, according to irrigation regimen. Then, the teeth were prepared and analyzed with SEM and EDS. Only in Group 1 [1 mL sodium hypochlorite (NaOCl) + 10 mL DW + 1 mL chlorhexidine (CHX) solution], Group 2 [1 mL NaOCl + 10 mL DW + 1 mL ethylenediaminetetraacetic acid (EDTA) + 10 mL DW + 1 mL CHX solution], and Group 3 [1 mL NaOCl + 10 mL DW + 1 mL citric acid (CA) + 10 mL DW + 1 mL CHX solution], the formation of CSL was observed. In the groups where CHX gel was used alone or in association with EDTA, CA, phosphoric acid (PA), and CHX solution, no formation of CSL was observed. According to the results found in the cases in which one wants to associate NaOCl with CHX, the protocol using PA (1 mL NaOCl + 10 mL DW + 1 mL PA + 10 mL DW + 1 mL CHX solution) did not induce formation of CSL. Microsc. Res. Tech., 2013. © 2012 Wiley Periodicals, Inc.     

Effect of time and ultrasonic activation on ethylenediaminetetraacetic acid on smear layer removal of the root canal

The aim of this study was to assess the effect of time and the ultrasonic activation of ethylenediaminetetraacetic acid (EDTA) in removing the smear layer of at root canal. A total of 60 bovine inferior incisors were transversely sectioned and instrumented; A smear layer was added in the root dentin surface. The specimen were then divided into six groups according to the following final irrigation protocols: Group (G) 1: conventional irrigation with sodium hypochlorite (NaOCl); G2: conventional irrigation with NaOCl + EDTA for 20 s; G3: conventional irrigation with NaOCl + EDTA for 60 s; G4: passive ultrasonic irrigation (PUI) with NaOCl; G5: PUI with NaOCl + PUI with EDTA for 20 s; G6: PUI + NaOCl and PUI with EDTA for 60 s. Samples were analyzed by scanning electron microscope (SEM) at ×500 increase. The images were measured by three blinded evaluators and classified in scores ranging from 1 to 5. The results were analyzed by the Pearson correlation test and the ANOVA nonparametric Kruskal–Wallis and Dunn's tests were used for the comparisons. Irrigated samples only with NaOCl (G1 and G4) had higher scores when compared with other groups. G5 and G6, irrigated with 17% EDTA and ultrasonic irrigation had lower scores. However, there was no statistically significant difference in G2 and G3, where there was no irrigation. It was concluded that irrigation with 17% EDTA for 20 s promoted the effective removal of smear layer, regardless of ultrasonic irrigation.     

Influence of Trigonella foenum graecum seed extract as root canal irrigation agent on root surfaces: A scanning electron microscope/energy dispersive X‐ray analysis study

The purpose of this in vitro study was to investigate the effect of Trigonella foenum graecum seed extract (TFGSE) as a root canal irrigation agent on the surface of instrumented root canals and on changes in the mineral contents of the root dentin. A total of 90 extracted human mature maxillary central incisor teeth with a single root and without root resorption were selected. The specimens were subdivided into five groups according to irrigation protocol groups G0: distilled water (n = 15): G1: Sodium hypochlorite (5.25% NaOCl); G2: 1% TFGSE G3: NaOCl +17% EDTA (3 min); G4: NaOCl+1% TFGSE; G5: 1% TFGSE +17% EDTA. All the roots were sectioned longitudinally into two halves and examined under scanning electron microscope/energy dispersive X‐ray analysis (SEM/EDX) to assess changes in the mineral content of the tooth. Smear layer removal from root canals was evaluated with scanning electron microscopy (SEM). A statistical analysis was performed using the Kruskal–Wallis test. The most effective irrigation protocols in removing smear layer occurred with TFGSE and NaOCl, both with rinsing with 17% EDTA. TFGSE was more effective than NaOCl for removing the smear layer. The results showed the ability of 1% TFGSE to remove the smear layer from the root canals. TFGSE is a promising alternative irrigation agent for root canals.     

Peracetic acid as a single endodontic irrigant: effects on microhardness,roughness and erosion of root canal dentin

The aim was to assess the effects of 1% peracetic acid (PAA) as a single endodontic irrigant on microhardness, roughness, and erosion of root canal dentin, compared with 2.5% sodium hypochlorite (NaOCl) and with 2.5% NaOCl combined with 17% EDTA. Forty human, single‐rooted tooth hemisections were submitted to Knoop microhardness test, before and after the following irrigation protocols: PAA = 1% PAA; NaOCl = 2.5% NaOCl; NaOCl‐EDTA‐NaOCl = 2.5% NaOCl +17% EDTA +2.5% NaOCl; and SS = saline. Another 40 roots were instrumented, irrigated with the same protocols, and sectioned longitudinally. The roughness analysis was performed on the mesial section using a confocal laser scanning microscope, whereas erosion was analyzed on each third of the distal section, using a scanning electron microscope. The data were analyzed using ANOVA and Tukey post‐tests, and Kruskal‐Wallis and Dunn post‐tests (α = .05). The PAA and NaOCl‐EDTA‐NaOCl groups showed no significant differences (p > .05); both promoted reduction in microhardness and increase in roughness, compared with the NaOCl and SS groups (p < .05). NaOCl‐EDTA‐NaOCl promoted higher erosion in the cervical and middle thirds than the other groups (p < .05); there was no difference among PAA, NaOCl, and SS (p > .05). There was also no difference among the groups regarding the apical third (p > .05). PAA used as a single endodontic irrigant caused reduction in root canal dentin microhardness and increase in roughness in a similar way to NaOCl‐EDTA‐NaOCl; however, PAA caused less erosion than NaOCl‐EDTA‐NaOCl.     

Qualitative analysis of smear layer treated with different etidronate concentrations: A scanning electron microscopy study

The aim of this study was to examine the smear layer removal capacity of various etidronate treatments. Seventy‐eight roots were instrumented up to apical size X4 and randomly divided into five treatment groups and a positive control group (n = 13). Groups were as follows: irrigation with 5 ml of sterile saline (control) for 3 min, 5 ml of 17% ethylenediaminetetraacetic acid (EDTA) for 3 min, 5 ml of 9% A1‐hydroxyethylidene‐1,1‐bisphosphonate (HEBP) for 3 min, 5 ml of 18% HEBP for 3 min, irrigation with 5 ml of 1% sodium hypochlorite (NaOCl) + 9% HEBP for 3 min, and 5 ml of 2% NaOCl + 18% HEBP for 3 min. The roots were examined using a scanning electron microscope. The smear layer scores in the 2% NaOCl + 18% HEBP group were lower than those in the other treatment groups and the control group (p < .05). There were no significant differences among the treatment groups in the smear layer scores of the coronal and middle thirds. However, the smear layer scores in the 2% NaOCl + 18% HEBP treatment group were lower those in the 9% HEBP and 18% HEBP treatment groups in the apical third (p < .05). In the clinical setting, the recommended concentration of HEBP is 18%, and it should be used with an oxidizing agent to ensure optimum smear layer removal.     

Persistence of resinous cement residues in dentin treated with different chemical removal protocols

The aim of this study was to evaluate the persistence of resin cement residues after dentin surface cleaning with different alcohol-based solutions or an essential oil (eucalyptol). Forty bovine teeth were sectioned in order to expose pulp chamber dentin to be washed with 1.0 mL of 2.5% sodium hypochlorite (NaOCl), followed by 0.1 mL of 17% EDTA application for 3 min, and final irrigation with 2.5% NaOCl. The specimens were air dried and resin-based cement was rubbed onto the dentine surface with a microbrush applicator. After 15 min, the surface was scrubbed with a cotton pellet and moistened with different dentin cleaning solutions, compounding the following groups: G1--95% ethanol, G2--70% ethanol, G3--70% isopropyl alcohol, or G4--eucalyptol. The dentin was scrubbed until the cement residues could not be visually detected. Sections were then processed for SEM and evaluated at × 500 magnification. Scores were attributed to each image according to the area covered by residual sealer, and data were subjected to Kruskal-Wallis at 5% significance. Eucalyptol promoted the most adequate dentin cleaning, although no statistical difference was detected amongst the groups (P > 0.05), except between the eucalyptol and 70% ethanol groups (P < 0.05). All the evaluated dentin cleaning solutions were unable to completely remove the cement residues from the dentin surface.     

Effects of chemical agents on physical properties and structure of primary pulp chamber dentin

This study evaluated the effects of chemical agents on the physical properties and structure of primary pulp chamber dentin using surface roughness, microhardness tests, and scanning electron microscopy (SEM). Twenty‐five primary teeth were sectioned exposing the pulp chamber and were divided into five groups (n = 5): NT, no treatment; SH1, 1% sodium hypochlorite (NaOCl); SH1U, 1% NaOCl + Endo‐PTC^®; SH1E, 1% NaOCl + 17% EDTA; and E, 17% EDTA. After dentin treatment, the specimens were submitted to roughness, microhardness testing, and SEM analysis. Roughness and microhardness data were submitted to one‐way ANOVA and Tukey's test (P < 0.05). The SH1E group showed the highest roughness, followed by the E group (P < 0.05) when compared with the NT, SH1, and SH1U groups. Microhardness values of SH1 and SH1U showed no significant difference as compared to the NT (control) group (P > 0.05). Microhardness values could not be obtained in the EDTA groups (SH1E and E). The presence of intertubular dentin with opened dentin tubules was observed in the NT, SH1, and SH1U groups. SH1E showed eroded and disorganized dentin with few opened tubules and the intertubular/peritubular dentin was partially removed. Considering the physical and structural approaches and the chemical agents studied, it can be concluded that NaOCl and NaOCl associated with Endo‐PTC^® were the agents that promoted the smallest changes in surface roughness, microhardness, and structure of the pulp chamber dentin of primary teeth. Microsc. Res. Tech. 77:52–56, 2014. © 2013 Wiley Periodicals, Inc.     

Effect of the root canal final rinse protocols on the debris and smear layer removal and on the push‐out strength of an epoxy‐based sealer

The aim of the present study was to evaluate the efficacy of QMiX, SmearClear, and 17% EDTA for the debris and smear layer removal from the root canal and its effects on the push‐out bond strength of an epoxy‐based sealer by scanning electron microscopy (SEM). Forty extracted human canines (n = 10) were assigned to the following final rinse protocols: G1‐distilled water (control), G2–17% EDTA, G3‐SmearClear, and G4‐QMiX. The specimens were submitted to a SEM analysis to evaluate the presence of debris and smear layer, respectively, in the apical or cervical segments. In sequence, forty extracted human maxillary canines with the root canals instrumented were divided into four groups (n = 10) similar to the SEM analysis study. After the filling with AH Plus, the roots were transversally sectioned to obtain dentinal slices. The specimens were submitted to a push‐out bond strength test using an electromechanical testing machine. The statistical analysis for the SEM and push‐out bond strength studies were performed using the Kruskal–Wallis and Dunn tests (α = 5%). There was no difference among the G2, G3, and G4 efficacy in removing the debris and smear layer (P > 0.05). The efficacy of these groups was superior to the control group. The push‐out bond strength values of G2, G3, and G4 were superior to the control group. The ability to remove the debris and smear layer by SmearClear and QMiX was as effective as the 17% EDTA. The final rinse with these solutions promoted similar push‐out bond strength values. Microsc. Res. Tech. 76:533–537, 2013. © 2013 Wiley Periodicals, Inc.     

Influence of passive ultrasonic irrigation on the efficiency of various irrigation solutions in removing smear layer: a scanning electron microscope study

To evaluate the influence of passive ultrasonic irrigation (PUI) to remove the smear layer with different irrigation solutions. Seventy‐eight single rooted mandibular premolars were used. The working lengths were measured and the root canals were prepared by using nickel titanium rotary files. The specimens were subjected to six different irrigation regimens: sodium hypochloride (NaOCl) with classic irrigation (CI); NaOCl with PUI; EDTA with CI; EDTA with PUI; QMix with CI; and QMix with PUI. The specimens were split longitudinally. Scanning electron microscopy images were taken to evaluate the amount of residual smear layer and scored. Statistical analysis was performed with the Kruskal–Wallis test. The Dunn's test was used for post hoc testing after the Kruskal–Wallis test. The smear layer scores of apical thirds were significantly higher than coronal and middle thirds except for NaOCl + CI group (p < 0.001). The irrigation with PUI improved the efficacy of all irrigation solutions on removal of smear layer in both coronal and middle thirds (p < 0.001). The PUI activation increased the activity of NaOCl, EDTA, and QMix, respectively without any significance. All irrigation regimens were significantly more effective in coronal and middle thirds compared to apical third. PUI significantly increased the efficacy of smear layer removal regardless of irrigation solution.     

Surface change of root canal dentin after the use of irrigation activation protocols: Electron microscopy and an energy‐dispersive X‐ray microanalysis

This study evaluated the mineral contents of root‐canal dentin after treatment with different irrigation activation protocols. One hundred and eight maxillary lateral incisor teeth were randomly divided into eight experimental groups and one control group. Root canals were prepared using ProTaper rotary files, with the exception of the Self‐Adjusting File (SAF) group. Canals were irrigated with 2 mL of 5% sodium hypochlorite (NaOCl) at each instrument change, and received a final flush with 10 mL of 17% ethylenediaminetetraacetic acid (EDTA) and 10 mL of 5% NaOCl for 1 min. The control group was irrigated with distilled water. Group I (GI): Needle syringe irrigation; Group II (GII): NaviTip FX; Group III (GIII): CanalBrush; Group IV (GIV): Manual dynamic activation with gutta‐percha; Group V (GV): Passive ultrasonic irrigation; Group VI (GVI): EndoActivator; Group VII (GVII): EndoVac; Group VIII (GVIII): SAF. The level of elemental composition was analyzed by a scanning electron microscopy and an energy‐dispersive spectrometer (EDS) system. The results were then statistically analyzed by one‐way ANOVA and Tukey tests. Ca/P ratio was changed after treatment with SAF and EndoActivator. The Ca, P, Mg, and S level changes were not statistically significant (P > 0.05). Final irrigation activation protocols did not alter the mineral level of root dentin surface. Microsc. Res. Tech. 76:893–896, 2013. © 2013 Wiley Periodicals, Inc.     

Effects of QMix and ethylenediaminetetraacetic acid on decalcification and erosion of root canal dentin

The aim of this study was to evaluate the effect of initial NaOCl on the decalcification and erosion ability of EDTA and QMix. Sixty‐maxillary‐incisors were bisected longitudinally and the tooth‐halves were used. The experiment was conducted in two‐sets. In set‐I, 80‐tooth halves were treated in the presence or absence of initial NaOCl and EDTA. In set‐II, 40‐tooth halves were immersed in NaOCl and QMix. After each treatment, calcium‐ion release was determined with flame photometry. The erosion was imaged using SEM. Initial NaOCl led to concentration‐ and time‐dependent increase in calcium removal effect of 17% EDTA (p < .05). The rate of calcium removal and root canal wall erosion was considerably more severe with the use of 5% NaOCl for 3 min (p < .05). QMix as a final solution showed less decalcification and erosion than 17% EDTA when used 5% NaOCl as an initial irrigant (p < .05). Optimizing the concentration and application time of NaOCl can decrease the decalcification effect of chelating agents.     

Persistence of endodontic methacrylate-based cement residues on dentin adhesive surface treated with different chemical removal protocols

The aim of this study was to evaluate the persistence of methacrylate‐based cement residues on the dentin, after dentin surface cleaning with ethanol or acetone, with or without previous application of a dentin adhesive. Forty bovine crown fragments were obtained and the dentin surface was washed with 1.0 mL of 2.5% sodium hypochlorite (NaOCl), followed by 0.1 mL of 17% ethylenediaminetetraacetic acid application for 3 min, and final irrigation with 2.5% NaOCl. The specimens were air dried and resin‐based cement was rubbed onto the dentine surface with a microbrush applicator. In 20 specimens, previously to cement, a dentin adhesive was applied in all surfaces. After 15 min, the surface was scrubbed with a cotton pellet and moistened with ethanol or acetone, compounding the following groups: G1—99.5% ethanol and G2—acetone, without previous use of dentin adhesive; G3—99.5% ethanol and G4—acetone, with previous use of dentin adhesive. The dentin surface was scrubbed until the cement residues could not be visually detected. Sections were then processed for scanning electron microscopy and evaluated at 500× magnification and scores were attributed to each image according to the area covered by residual sealer, and data were subjected to Kruskal–Wallis at 5% significance. The lower residue presence was observed in G3 (P = 0.005). All surface presented cement residues when acetone was used as cleaning solution (P = 0.0005). The cleaning solutions were unable to completely remove the cement residues from both surfaces. The ethanol used after previous application of the dentin adhesive promoted the lower presence of residues. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

Efficacy of different final irrigant activation protocols on smear layer removal by EDTA and citric acid

The aim of this study was to evaluate the influence of different activation protocols for chelating agents used after chemo‐mechanical preparation (CMP), for smear layer (SL) removal. Forty‐five single‐rooted human premolars with straight canals and fully formed apex were selected. The specimens were randomly divided into three groups depending on the chelating agent used for smear layer removal: distilled water (DW, control group); 17% ethylenediaminetetraacetic acid (EDTA); and 10% citric acid (CA). Each group was further divided into three subgroups according to the activation protocol used: no‐activation (NA), manual dynamic activation (MDA), or sonic activation (SA). After CMP, all specimens were sectioned and processed for observation of the apical thirds by using scanning electron microscopy (SEM). Two calibrated evaluators attributed scores to each specimen. The differences between activation protocols were analyzed with Kruskal‐Wallis and Mann‐Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between each root canal third. When chelating agents were activated, either by MDA or SA, it was obtained the best cleaning results with no significant difference between EDTA and CA (P > 0.05). Sonic activation showed the best results when root canal thirds were analyzed, in comparison to MDA and NA groups (P < 0.05). The activation of chelating agents, independent of the protocol used, benefits smear layer removal from root canals. Microsc. Res. Tech. 76:364–369, 2013. © 2013 Wiley Periodicals, Inc.     

Comparison of different irrigation activation techniques on smear layer removal: An in vitro study

The purpose of this study was to evaluate the efficiency of different irrigation activation techniques on smear layer removal. About 80 single‐rooted human maxillary central teeth were decoronated to a standardized length.The samples were prepared by using ProTaper system to size F4 and divided into eight equal groups (n = 10) according to the final irrigation activation technique; distilled water was used as an irrigant in Group 1. The other groups were treated with 2.5% NaOCl and 17% EDTA, respectively. Conventional syringe irrigation (CSI) was used in Group 2. Irrigation solutions were activated using passive ultrasonic irrigation (PUI, Group 3), EndoVac apical negative pressure (ANP, Group 4), diode laser (Group 5), Nd:YAG laser (Group 6), Er:YAG laser (Group 7), and Er:YAG laser using with photon‐induced photoacoustic streaming (PIPS?, Group 8). Teeth were split longitudinally and subjected to scanning electron microscope (SEM). PIPS showed the best removal of smear layer when compared with PUI, ANP, Nd:YAG, and Er:YAG, but the difference was not statistically significant (P > 0.05). Smear layer scores obtained with PIPS technique were statistically significant different from those of obtained with control, CSI and diode laser groups (P < 0.05). All experimental irrigation techniques except ANP and diode laser removed smear layer more effectively at the coronal and middle levels compared to the apical level (P < 0.05). Irrigation activated/delivered techniques except diode laser have a positive effect on removing of smear layer. Microsc. Res. Tech. 78:230–239, 2015. © 2015 Wiley Periodicals, Inc.