Use Of NaOCl Research Articles

Comparison of Different Dentin Pretreatment Protocols on the Bond Strength of Glass Fiber Post Using Self-etching Adhesive

IntroductionThis study compared the influence of different irrigants with and without ultrasound or laser irradiation on the bond strength of glass fiber posts using a self-etching adhesive in a supplementary dentin pretreatment. MethodsNinety bovine incisor roots were divided into 3 groups according to the irrigant tested: 2% chlorhexidine (CHX) (n = 30); 2.5% sodium hypochlorite (NaOCl) (n = 30), and saline solution (control) (n = 30). Each group was randomly divided into 3 subgroups according to the supplementary dentin pretreatment: ultrasound, Nd:YAG laser, and nonsupplemented (control). A self-etching adhesive system (Futurabond DC; VOCO GmbH, Cuxhaven, Germany) was used, and the glass fiber posts were cemented with dual-cure epoxy-based luting agent (Bifix QM, VOCO GmbH). All roots were sectioned transversely, and the push-out test was performed. Failure mode analysis was also evaluated. ResultsBond strength decreased significantly after the use of 2.5% NaOCl in all root thirds (P < .05). CHX showed no difference in the mean bond strength value compared with saline solution (P > .05). The supplementary dentin pretreatment using the Nd:YAG laser or ultrasound did not improve the bond strength values for both NaOCl and CHX (P > .05). Moreover, the apical third exhibited the lowest mean bond strength values (P < .05). Analysis indicated that the predominant failure mode was the mixed type. ConclusionsRegardless of the irrigant used, the supplementary dentin pretreatment with ultrasound or laser irradiation showed no improvement in bond strength. Also, the use of NaOCl decreased the bond strength of glass fiber posts using a self-etching adhesive system, whereas CHX preserved it.

Antibiofilm activity of three irrigation protocols activated by ultrasonic, diode laser or Er:YAG laser in vitro.

To investigate the impact of three irrigation protocols, activated by three different methods, on mature biofilms of Enterococcus faecalis in vitro. Root canals in 280 single-rooted teeth were instrumented using a rotary Ni-Ti system. Biofilms of E. faecalis were generated based on a previously established protocol. Samples were randomly divided into three experimental (n = 80) and one control (n = 40) group based on the irrigation protocol employed: group 1 (NaOCl + Etidronic acid), 1 : 1 mixture of 6% NaOCl and 18% etidronic acid; group 2 (NaOCl-EDTA), 3% NaOCl followed by 17% EDTA; group 3 (NaOCl-EDTA-NaOCl), 3% NaOCl followed by 17% EDTA and a final flush of 3% NaOCl. Saline served as the control. Samples were further divided into four subgroups (n = 20) based on the activation method: subgroup A, no activation; subgroup B, ultrasonic activation; group C, diode laser; group D, Er:YAG laser. Confocal laser scanning microscopy was used to assess bacterial viability in situ. Root dentine powder was obtained for determining the colony-forming units (CFU mL(-1) ). Data were analysed by appropriate statistical analyses with P = 0.05. All experimental irrigation protocols caused complete destruction of the biofilm in the root canal lumen. Within the dentinal tubules, all groups had a significantly higher percentage of dead bacteria than the saline control (P < 0.05). There was no significant difference between NaOCl + etidronic acid and NaOCl-EDTA-NaOCl (P > 0.05), whereas both groups brought about more bacterial reduction than NaOCl-EDTA (P < 0.05). There was no significant difference between diode laser and Er:YAG laser in any of the groups (P > 0.05). Both diode and Er:YAG laser were more effective than ultrasonic activation and conventional syringe irrigation in reducing E. fecalis biofilms (P < 0.05). The use of NaOCl after or in combination with a chelator caused the greatest reduction of E. faecalis. Diode laser and Er:YAG laser activation were superior to ultrasonics in dentinal tubule disinfection.

Effects of sodium hypoclorite as disinfectant material previous to pulpotomies in primary teeth.

Sodium hypochlorite (NaOCl) can be used to promote healing vital pulpotomies as an antibacterial agent. The aim of the present study was to histologically analyze the pulpal response of human primary teeth pulp following calcium hydroxide (CH) and mineral trioxide aggregate (MTA) pulpotomies with and without 5% NaOCl. One hundred twenty-eight primary molars were randomly divided into two main groups according to pulpotomy material (CH/MTA) and into two subgroups according to selected cleansing agent (NaOCl/physiologic saline) used in the pulpotomy procedure. Thirty-four successfully treated teeth whose successor roots had completed formation of at least two thirds of their lengths were extracted for histological evaluation. Fisher's exact test, Pearson's Chi-square test, and Mann-Whitney U test with Bonferroni correction were used for statistical analysis. No significant differences in any of the tested parameters were observed between the NaOCl and physiologic saline subgroups of either the CH or MTA groups. Pulpal inflammation was significantly higher in the CH-treated teeth as compared with the MTA-treated teeth, whereas hard tissue bridge formation was significantly higher in the MTA-treated teeth as compared with the CH-treated teeth but regardless of cleansing agent (p < 0.025). The use of NaOCl does not affect the success of CH or MTA pulpotomies. Regardless of cleansing agent, MTA was found to be superior to CH. The proper medicament selection is more important than the choice of cleaning agent in vital pulpotomies.

Effectiveness of several solutions to prevent the formation of precipitate due to the interaction between sodium hypochlorite and chlorhexidine and its effect on bond strength of an epoxy-based sealer.

To evaluate the effectiveness of isopropyl alcohol, saline or distilled water to prevent the precipitate formed between sodium hypochlorite (NaOCl) and chlorhexidine (CHX) and its effect on the bond strength of an epoxy-based sealer in radicular dentine. The root canals of 50 extracted human canines (n = 10) were instrumented. In G1, root canals were irrigated with 17% EDTA and 2.5% NaOCl; G2, as G1, except that 2% CHX was used as the final irrigant. In the other groups, intermediate flushes with isopropyl alcohol (G3), saline (G4) or distilled water (G5) were used between NaOCl and CHX. The specimens were submitted to SEM analysis to evaluate the presence of debris and smear layer, in the apical and cervical segments. In sequence, fifty extracted human canines were distributed into five groups (n = 10), similar to the SEM study. After root filling, the roots were sectioned transversally to obtain dentine slices, in the cervical, middle and apical thirds. The root filling was submitted to a push-out bond strength test using an electromechanical testing machine. Statistical analysis was performed using Kruskal-Wallis and Dunn's tests (α = 5%). All groups had similar amounts of residue precipitated on the canal walls (P > 0.05). The push-out bond strength values were similar for all groups, independently of the root third evaluated (P > 0.05). Isopropyl alcohol, saline and distilled water failed to prevent the precipitation of residues on canal walls following the use of NaOCl and CHX. The residues did not interfere with the push-out bond strength of the root filling.

Effectiveness of different irrigation systems on smear layer removal: A scanning electron microscopic study.

Objectives:To evaluate effectiveness of the apical negative pressure irrigation (EndoVac), passive ultrasonic irrigation (PUI), and conventional needle irrigation (CI) systems on smear layer (SR) removal.Materials and Methods:Sixty single-rooted canines were prepared using NiTi rotary files and subjected to different irrigation regimens: EndoVac with NaOCl (Group 1) or NaOCl/EDTA (Group 2); PUI with NaOCl (Group 3) or NaOCl/EDTA (Group 4); CI with NaOCl (Group 5) or NaOCl/EDTA (Group 6). The roots were split longitudinally. SEM images were taken to evaluate the amount of residual SR.Results:In Groups 1, 3, and 5, there was no removal of SR (P > 0.05). The coronal thirds within Groups 2, 4, and 6 were cleaned completely, but the middle and the apical thirds was achieved partially or completely (P > 0.05).Conclusion:Regardless of which irrigation system was used, the use of NaOCl alone failed to remove the SR. In NaOCl/EDTA combination groups, the SR was removed partially or completely and no statistical significance. This study demonstrated that in order to remove the SR should be used EDTA solution for final irrigation in the root canal, regardless of the technique in each of the three.

Consequences of enamel preparation with sodium hypochlorite, polyacrylic and phosphoric acids for the bonding of brackets with resin-modified glass ionomer cements

The aim of this study was to evaluate the effects of deproteinization with 5.25% sodium hypochlorite (NaOCl) prior to enamel conditioning with 10% polyacrylic acid (PAA) and 35% phosphoric acid (PA) on the bond strength (BS) of brackets bonded with resin-modified glass ionomer cement (RMGIC). One hundred human premolars extracted for orthodontic reasons were divided into 5 groups (n = 20 in each group): G1 (control), enamel conditioning with PA, application of adhesive and bonding of brackets with TransbondTM XT composite resin (3M/Unitek, Monrovia, CA, USA); G2, enamel conditioning with PAA and bonding with RMGIC (Fuji OrthoTM LC, GC America, Alsip, IL, USA); G3, NaOCl-treated enamel, conditioning with PAA and bonding with RMGIC; G4, enamel conditioning with PA and bonding with RMGIC; and G5, NaOCl-treated enamel, conditioning with PA and bonding with RMGIC. Once the brackets were bonded, the teeth were stored in distilled water for 24 hours at room temperature and pressure until being subjected to shear stress in a Universal Mechanical Testing Machine (EMIC® DL 500, São José dos Pinhais, PR, Brazil). The BS value was higher in G1 (17.08 ± 6.39) than in any of the experimental groups (p < 0.05). No statistically significant differences were noted between groups using RMGIC (p > 0.05), except between G3 (9.86 ± 2.90) and G5 (5.00 ± 2.49). No statistically significant differences were noted between the mean Adhesive Remnant Index values among the evaluated groups (p > 0.05). Conclusion: The use of NaOCl combined with PAA increased the BS of brackets bonded with RMGIC. The deproteinization of the group treated with PA reduced the shear bond strength of the brackets.

The use of NaOCl in combination with CHX produces cytotoxic product

The combination of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) yields a "precipitate potentially toxic" (PPT). The aim of this study was to evaluate the tissue response to implanted polyethylene tubes filled with PPT-soaked fibrin sponge. Forty rats received four polyethylene tubes each; each tube was filled with fibrin sponge soaked by 2.5 % NaOCl, 2.0 % CHX, PPT (2.5 % NaOCl plus 2.0 % CHX), or not soaked (control). The observation time points were 7, 15, 30, 60, and 90 days. At each time point, eight animals were killed, and the tubes and surrounding tissues were removed, fixed, and prepared for light microscopic analysis by performing glycol methacrylate embedding, serial cutting into 3-μm sections, and hematoxylin-eosin staining. Qualitative and quantitative evaluations of the reactions were performed. Results were statistically analyzed by Kruskal-Wallis test (p < 0.05). All chemical solutions caused moderate reactions at 7 days. On day 30, PPT group was more cytotoxic than the control group and the CHX group (p < 0.05). On days 15 and 60, PPT group was more cytotoxic than the control group (p < 0.05). On day 90, there was no statistically significant difference between the different groups. PPT is more cytotoxic than NaOCl and CHX alone, particularly in the short term. Protocols which suggest the use of CHX and NaOCl must be revised because this mixture produces cytotoxic product.

Synergistic effects of elevated carbon dioxide and sodium hypochlorite on survival and impairment of three phytoplankton species

Sodium hypochlorite (NaOCl) is widely used to disinfect seawater in power plant cooling systems in order to reduce biofouling, and in ballast water treatment systems to prevent transport of exotic marine species. While the toxicity of NaOCl is expected to increase by ongoing ocean acidification, and many experimental studies have shown how algal calcification, photosynthesis and growth respond to ocean acidification, no studies have investigated the relationship between NaOCl toxicity and increased . Therefore, we investigated whether the impacts of NaOCl on survival, chlorophyll a (Chl-a), and effective quantum yield in three marine phytoplankton belonging to different taxonomic classes are increased under high levels. Our results show that all biological parameters of the three species decreased under increasing NaOCl concentration, but increasing concentration alone (from 450 to 715 ) had no effect on any of these parameters in the organisms. However, due to the synergistic effects between NaOCl and , the survival and Chl-a content in two of the species, Thalassiosira eccentrica and Heterosigma akashiwo, were significantly reduced under high when NaOCl was also elevated. The results show that combined exposure to high and NaOCl results in increasing toxicity of NaOCl in some marine phytoplankton. Consequently, greater caution with use of NaOCl will be required, as its use is widespread in coastal waters.

Effects of sodium hypochlorite associated with EDTA and etidronate on apical root transportation

To evaluate the influence of sodium hypochlorite associated with EDTA and etidronate on apical root transportation. Forty-five roots of human mandibular molars with curvatures of 15-25° were embedded in acrylic resin to allow standardized angulation of the initial and final radiographs. The pre-instrumentation radiographs of the mesiobuccal canal of each root were taken using a radiograph digital sensor with a size 15 K-file in the canal. The canals were prepared with the ProTaper Universal system (Dentsply Maillefer, Ballaigues, Switzerland), using one of the following irrigation regimens during the instrumentation (n = 15): G1 - irrigation with 20 mL of saline solution (control); G2 - alternating irrigation with 2.5% hypochlorite solution (NaOCl) (15 mL); and 17% ethylenediaminetetraacetic acid (EDTA) (5 mL). During instrumentation, the canal was filled with NaOCl and then between each exchange of instrument filled with EDTA for 1 min, and G3 - irrigation with 20 mL of 5% NaOCl and 18% etidronate solution (HEBP) mixed in equal parts. The postinstrumentation radiographs were made with a F3 instrument in the canal. The images were magnified and superposed with Adobe Photoshop software (Adobe Systems, Mountain View, CA, USA). Apical transportation was determined with AutoCAD 2012 software (Autodesk Inc., San Rafael, CA, USA) by measuring the distance in millimetres between the tips of the instruments. The results were subjected to the nonparametric statistical Kruskal-Wallis test (α < 0.05). The median transportation and interquartile range values were 0.00 ± 0.05 for G1, 0.08 ± 0.23 for G2 and 0.13 ± 0.14 for G3. Comparison between groups showed that apical transportation in G3 was significantly greater than in G1 (P < 0.05). The use of NaOCl associated with etidronate increased apical transportation in the canals of extracted teeth.

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

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

Effect of Different Final Irrigation Solutions on Dentinal Tubule Penetration Depth and Percentage of Root Canal Sealer

IntroductionThe purpose of this study was to evaluate the effects of different solutions used for final irrigation on sealer penetration into dentinal tubules. MethodsThirty-two recently extracted human mandibular premolar teeth were treated with sodium hypochlorite (NaOCl) irrigation. The samples were divided into 4 groups according to the final irrigation solution used: (1) the EDTA group: 17% EDTA + 2.5% NaOCl, (2) the maleic acid (MA) group: 7% MA + 2.5% NaOCl, (3) the citric acid (CA) group: 10% CA + 2.5% NaOCl, and (4) the control group: 2.5% NaOCl. All teeth were obturated using the cold lateral condensation technique with gutta-percha and AH 26 sealer (Dentsply; DeTrey, Konstanz, Germany) labeled with fluorescent dye. The teeth were sectioned at distances of 2, 5, and 8 mm from the root apex. Total percentage and maximum depth of sealer penetration were measured using confocal laser scanning microscopy. ResultsThe Kruskal-Wallis analysis results showed that there was a significant difference in the percentage and maximum depth of sealer penetration among all groups in all sections (P < .05).The coronal sections in each group showed a significantly higher percentage and maximum depth of sealer penetration than did the apical and middle sections (P < .05). ConclusionsFinal irrigation with EDTA, MA, and CA after the use of NaOCl affected sealer penetration. However, there was no significant difference between these experimental groups (EDTA, MA, and CA) in all sections.

Antimicrobial Treatment of Grapes Using Sodium Hypochlorite in Winemaking and Its Effects on the Chemical and Sensory Characteristics of Wines

This study was performed to examine the use of NaOCl as an alternative antimicrobial compound in winemaking because of the potential health problems that may arise as a result of the use of SO2. For this, the blank (non-treated), control (SO2-added), and sample (NaOCl-treated) wines were made, and microbial and chemical changes including sensory characteristics were analyzed during the fermentation periods. Treatment of grapes with NaOCl decreased the initial contaminating microbial population in grape must, resulting in higher growth of yeast and lactic acid bacteria. After 200 days of fermentation, the chemical analysis of sample wine revealed that it had higher ethanol content, redness (a*), and concentrations of fruity ester compounds and lower total acidity than the control. In the sensory analyses, the sample wine obtained a higher overall acceptability score (5.70) than the control (4.26). This result reveals that NaOCl can be used as an alternative to SO2 in winemaking for inhibiting the growth of contaminating microorganisms.

Deproteinization technique stabilizes the adhesion of the fiberglass post relined with resin composite to root canal

To evaluate the effects of pretreatment of root dentin by 5.25% sodium hypochlorite (NaOCl) alone, associated with 2% chlorhexidine in gel base (CHX) and/or ethanol (EtOH), and the air-drying technique (Air) on the bond strength and adhesive durability of fiberglass post relined with resin composite to root dentin. A total of 100 bovine incisor roots were divided into 10 groups: G1 (control), irrigation with physiologic solution; G2, Air; G3, NaOCl; G4, NaOCl + Air; G5, NaOCl + EtOH; G6, NaOCl + EtOH + Air; G7, NaOCl + CHX; G8, NaOCl + CHX + Air; G9, NaOCl + CHX + EtOH; G10, NaOCl + CHX + EtOH + Air. Fiberglass post relined with resin composite was cemented and each group was randomly divided into two subgroups: 24 h of water storage and 12 months of water storage. The push-out test was performed and bond strength values were analyzed by ANOVA and Tukey's test. The use of NaOCl alone or associated with CHX had the highest values of bond strength with or without Air in the immediate and stored groups, being statistically similar to the immediate control group (p > 0.05). The groups using EtOH or Air alone had lower bond strength in the immediate and stored groups (p < 0.05). A significant decrease with the time of the bond strength in the control group was observed after 12 months of storage (p > 0.05). The use of NaOCl or NaOCl associated with CHX preserved the bond strength immediate and for 12 months. The air-drying technique and the other associations decreased the immediate bond strength values.

English

The aim of this study was to investigate the effect of sodium hypochlorite (NaOCl) on the shear bond strength of fifth- and seventh- generation adhesive resins to coronal dentin. Thirty human third molars were selected and sectioned into two halves buccolingually. Sixty samples were randomly divided into four groups (n = 15). The crowns were separated from the roots. Subsequent to the removal of pulp tissue, the inner surfaces of tooth crowns were rubbed using 600-grit silicon carbide paper in order to obtain flat dentin surface. In group 1, Single Bond (the fifth generation adhesive resin) was used. In group 2, single bond adhesive resin was used subsequent to NaOCl solution application. In groups 3 and 4, the same procedures as described for groups 1 and 2, were repeated respectively, except for the fact that instead of the fifth generation adhesive resin, the seventh generation adhesive resin (Clearfil S3 Bond) was used. Subsequent to composite resin placement over dentin surfaces, the samples were subjected to shear bond strength test. Data were analyzed using ANOVA and Tukey test. The significance level was set at p&lt;0.05. There were statistically significant differences between the groups (p&lt;0.05). The use of NaOCl reduced the shear bond strength of fifth- and seventh-generation adhesive resins to dentin and there was no difference in the shearing bond strength of both adhesive resins. &nbsp; Key words:&nbsp;Shear bond strength, sodium hypochlorite, fifth generation adhesive resins, seventh generation adhesive resins.

Evaluation of the Interaction between Endodontic Sealers and Dentin Treated with Different Irrigant Solutions

Introduction Dentin surface treatment with different substances might cause alterations in chemical and structural compositions of the human dentin. The aim of this study was to investigate the wettability of endodontic sealers in contact with dentin treated with 5.25% sodium hypochlorite (NaOCl) and 2% chlorhexidine (CHX) in the presence or absence of smear layer. Methods Thirty-six dentin slices were used. They were irrigated with NaOCl and washed with distilled water (DW) to simulate irrigation during chemomechanical preparation. After this procedure, the samples were divided into 6 groups: group 1, DW (control); group 2, NaOCl + DW; group 3, CHX + DW; group 4, ethylenediaminetetraacetic acid (EDTA) + DW; group 5, EDTA + DW + NaOCl + DW; group 6, EDTA + DW + CHX + DW. The Ramé-Hart goniometer was used to measure the contact angle between the dentin surfaces and the AH Plus and Real Seal SE sealers. Data were statistically analyzed. Results With regard to the contact angle between AH Plus and treated surfaces, the values of contact angle were lower when CHX was used, regardless of the presence or absence of smear layer. When Real Seal SE was evaluated, in the absence of smear layer, CHX presented lower values of contact angle. In the presence of smear layer, the use of NaOCl and CHX did not favor the spread of the sealer. Conclusions The present study has revealed that smear layer removal and final flush with CHX favor the wettability of AH Plus and Real Seal SE sealers.

The importance of final rinse after disinfection of gutta-percha and Resilon cones

The aim of this study was to evaluate the morphologic alterations on the surface of gutta-percha and Resilon cones exposed to disinfectant solutions. Fifty-six gutta-percha and Resilon cones were used. Seven groups were analyzed: G1: control; G2, G3, and G4: 5.25% NaOCl, 2% CHX, and MTAD, respectively, without final rinse; G5, G6, and G7: the same solutions with final rinse. Then the samples were analyzed by means of scanning electron microscopy and energy dispersive spectroscopy. Regarding the use of NaOCl without rinse, there was chloride crystal formation in all samples. When the cones were rinsed, the crystals were removed. When 2% chlorhexidine was used, no change was observed. MTAD without rinse showed the presence of a precipitate in gutta-percha cones. When the cones were rinsed, it was eliminated. The final rinse is essential, especially when NaOCl and MTAD are used in the cones' disinfection process.

Effect of endodontic irrigating solutions on the adhesive bond strength to dentin

PURPOSE: To evaluate the bond strength of a total-etching adhesive system to dentin irrigated with 1% sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid 17% (EDTA). METHODS: Thirty human molars were sectioned 3mm below the oclusal surface and were randomly divided into 3 groups (n=10): G1, no treatment (control); G2, 1% NaOCl; G3, NaOCl followed by EDTA. The specimens received the total-etching adhesive system, restored with microhybrid composite resin, sectioned and trimmed to create 4 hourglass-shaped slabs of each tooth. The slabs were tested in microtensile bond strength in a universal testing machine (Emic DL 2000) at a crosshead speed of 0.5 mm/min until fracture. The results were analyzed statistically by ANOVA and Newman-Keuls test. G2 samples were not submitted to the test because they fractured just before testing, and its values were considered zero to the statistical analysis. RESULTS: The means and standard deviations (MPa) were: G1, 8.41 (±3.51); G2, 0.0 (±0.00); G3, 8.47 (±3.53). CONCLUSION: It was concluded that the application of the NaOCl irrigating solution significantly decreased the bond strength values. The use of NaOCl followed by EDTA resulted in bond strength values not statistically different from control group.

Effect of aquatine endodontic cleanser on smear layer removal in the root canals of ex vivo human teeth

ObjectivesThe purpose of this study was to measure and compare the root canal cleanliness and smear layer removal effectiveness of Aquatine Endodontic Cleanser (Aquatine EC) when used as an endodontic irrigating solution in comparison with 6% sodium hypochlorite (NaOCl).Material and MethodsForty-five human teeth were randomly allocated to five treatment groups; the pulp chamber was accessed, cleaned, and shaped by using ProTaper and ProFile rotary instrumentation to an ISO size #40. The teeth were then processed for scanning electron microscopy, and the root canal cleanliness and removal of smear layer were examined.ResultsThe most effective removal of smear layer occurred with Aquatine EC and NaOCl, both with a rinse of EDTA.ConclusionsAquatine EC appears to be the first hypochlorous acid approved by the FDA to be a possible alternative to the use of NaOCl as an intracanal irrigant. Further research is needed to identify safer and more effective alternatives to the use of NaOCl irrigation in endodontics.

Effectiveness of Chemomechanical Preparation with Alternating Use of Sodium Hypochlorite and EDTA in Eliminating Intracanal Enterococcus faecalis Biofilm

IntroductionThe elimination of microorganisms from root canals is a critical step in endodontic treatment. We aimed to evaluate the antimicrobial effectiveness of an alternating irrigation regimen during chemomechanical preparation (CMP). MethodsDuring 21 days, root canals of extracted human teeth were infected with Enterococcus faecalis, and colonization was confirmed by scanning electron microscopy (SEM). Canals were irrigated with saline solution (control group), with 5.25% NaOCl followed by a final rinse with 17% EDTA (conventional irrigation group), or with the alternating use of NaOCl and EDTA (alternating irrigation [AI] group). Samples were taken before treatment (S1), after CMP (S2), and during the following 14 days. Two specimens/group were analyzed by SEM. ResultsThe AI group yielded negative agar and liquid cultures from immediately after CMP and from the 5th day on, respectively. SEM confirmed several bacterium-free sites in the AI group. ConclusionThe irrigation regimen based on the alternating use of NaOCl and EDTA seems to be a promising endodontic tool because it promoted the elimination of root canal E. faecalis biofilms throughout the experimental period.

Effects of Different Exposure Times and Concentrations of Sodium Hypochlorite/Ethylenediaminetetraacetic Acid on the Structural Integrity of Mineralized Dentin

Introduction This study tested the null hypothesis that there is no difference between the use of 1.3% NaOCl/17% ethylenediaminetetraacetic acid (EDTA) and 5.25% NaOCl/17% EDTA irrigation regimens on the collagen degradation and flexural strength reduction in mineralized dentin. Methods Dentin powder and mineralized dentin sections were immersed in 1.3% or 5.25% NaOCl for 10–240 minutes and then rinsed with 17% EDTA as the final irrigant for 2 minutes. Untreated mineralized dentin powder/sections served as controls in the respective experiments. Dentin powders were examined by using Fourier transform infrared (FT-IR) spectroscopy to analyze their relative subsurface intact collagen content with the apatite/collagen ratio. Hydrated dentin sections were subjected to 3-point flexure under water for determining their flexural strengths. Results Collagen degradation was significantly increased and the flexural strength of mineralized dentin was significantly reduced after the use of 5.25% NaOCl as the initial irrigant for more than 1 hour ( P < .05). Conversely, changes were insignificant when 1.3% NaOCl was used as the initial irrigant for up to 4 hours (Kruskal-Wallis analysis of variance, n = 10, P < .05). Conclusions The null hypothesis was rejected. The deleterious effects attributed to the use of NaOCl on dentin are concentration-dependent and time-dependent and are not associated with the demineralization caused by the use of EDTA as the final active irrigant.