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

Abstract

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

Effect of MTAD on the bond strength to enamel and dentin

The purpose of this study was to compare the effect of MTAD (a mixture of a tetracycline isomer [doxycycline], an acid [citric acid], and a detergent [Tween 80]) and phosphoric acid on the bond strength to enamel and dentin using a conventional OptiBond Solo Plus dentin adhesive system. One hundred flat surfaces (50 enamel/50 dentin) were prepared for bonding. Specimens were embedded in acrylic with the flat surface exposed. One of the following surface treatments was applied before bonding composite with Optibond Solo Plus (Kerr Corp): 1 min NaOCl/1 min EDTA; 1 min NaOCl/1 min MTAD; 30 s etch with H3PO4 (positive control), 2 min saline (negative control), or 20 min NaOCl/5 min MTAD (clinical protocol for MTAD). Shear bond strength was tested 30 min after bonding. Data were analyzed using a one-way ANOVA followed by the Student-Newman-Keuls multiple comparison method. Surface pretreatment with acid etch resulted in the greatest enamel bond strengths (p < 0.05). All surface pretreatments were superior to saline for dentinal bonding (p < 0.05). On the basis of our findings, it appears that teeth endodontically treated with the MTAD protocol for clinical use (20 min 1.3% NaOCl/5 min MTAD) may not need any additional dentin conditioning before the application of the dental adhesive.     

Adhesion of Epiphany self-etch sealer to dentin treated with intracanal irrigating solutions

Introduction

This in vitro study assessed the adhesion of Epiphany self-etch (SE) root canal sealer to dentin treated with different irrigation regimens.

Methods

Flat dentin surfaces were obtained from human third molar teeth; smear layer was created on each sample. Five groups of 10 samples each were conditioned with one of the following regimens: (1) deionized water for 10 minutes; (2) 5% sodium hypochlorite (NaOCl) for 10 minutes; (3) 5% NaOCl for 10 minutes and then 10% sodium ascorbate (Na-Ascr) for 10 minutes; (4) 5% NaOCl for 10 minutes and then 2% chlorhexidine (CHX) for 5 minutes; or (5) 5% NaOCl for 10 minutes and then 10% Na-Ascr for 10 minutes, followed by 2% CHX for 5 minutes. The conditioned dentin surfaces were dried with absorbent paper points. The Epiphany SE sealer was placed on each dentin surface with the use of hollow stainless steel tubes with specific diameter and height. The samples were stored in 100% humidity at 37°C for 7 days and then tested for shear bond strength in a universal testing machine.

Results

Shear bond strength data were analyzed by one-way analysis of variance and Tukey post hoc tests (P < .05). There were statistically significant differences among the groups.

Conclusions

NaOCl decreased the bond strength of Epiphany SE sealer to dentin, whereas the use of Na-Ascr reversed this negative effect of NaOCl. CHX had neither negative nor positive influence on the bond strength.     

Adhesion of Epiphany and AH Plus sealers to human root dentin treated with different solutions

This study evaluated comparatively the adhesion of Epiphany and AH Plus endodontic sealers to human root dentin treated with 1% NaOCl and 1% NaOCl+17% EDTA, using the push-out test. Sixty root cylinders obtained from maxillary canines had the canals prepared and were randomly assigned to 3 groups (n=20), according to root dentin treatment: GI - distilled water (control), GII - 1% NaOCl and GIII - 1% NaOCl+17% EDTA. Each group was divided into 2 subgroups (n=10) filled with either Epiphany or AH Plus. Bond strength push-out test data (kN) were obtained and analyzed statistically by ANOVA and Tukey's post-hoc test. There was statistically significant difference between sealers (AH Plus: 0.78 +/- 0.13; Epiphany: 0.61 +/- 0.19; p<0.01) and among root dentin treatments (distilled water: 0.58 +/- 0.19; 1% NaOCl: 0.71 +/- 0.12; 1% NaOCl+17% EDTA: 0.80 +/- 0.17; p<0.05). In conclusion, AH Plus sealer presented greater adhesion to dentin than Epiphany, regardless of the treatment of root canal walls.     

Residual antibacterial activity of chlorhexidine and MTAD in human root dentin in vitro

The purpose of this in vitro study was to compare the antimicrobial substantivity of BioPure MTAD, 2% chlorhexidine (CHX) and 2.6% sodium hypochlorite (NaOCl) in human root dentin. One hundred and ten dentin tubes prepared from human maxillary incisors were infected in vitro for 14 days with Enterococcus faecalis. The specimens were divided into five groups as follows: CHX; BioPure MTAD; NaOCl; infected dentin tubes (positive control); and sterile dentin tubes (negative control). Dentin chips were collected with round burs into Brain Heart Infusion (BHI) broth. After culturing, the number of colony-forming units (CFU) was counted. In all experimental groups, CFU was minimum after treatment (day 0), and the results obtained were significantly different from each other at any time period (P < 0.05). After treatment, the NaOCI group and BioPure MTAD group showed the lowest and highest number of CFU, respectively. In each group, the number of CFUs increased significantly by time-lapse (P < 0.05). In conclusion, the substantivity of BioPure MTAD was significantly greater than CHX and NaOCl.     

Effect of endodontic irrigation on bonding of resin cement to radicular dentin

The influence of endodontic irrigation on shear bond strengths of resin cement to radicular dentin was investigated. Human radicular dentin blocks were divided into four groups and subjected to one of four endodontic irrigations: ethylenediaminetetraacetic acid (EDTA) group, 17% EDTA for 60 s; EDTA/sodium hypochlorite (NaOCl) group, 17% EDTA for 60 s followed by 10 ml of 5% NaOCl for 15 s; NaOCl group, 10 ml of 5% NaOCl for 15 s; and control group, no treatment. Morphological changes of dentin surface after endodontic irrigation were observed by scanning electron microscopy (SEM). A resin block was bonded to the radicular dentin after irrigation using resin cement with either wet-bonding (Uni-Etch/One-Step; Bisco) or self-etching (Tyrian SPE/One-Step Plus; Bisco) adhesives. Shear bond strengths were measured and the penetration of resin tags into dentinal tubules at resin-dentin interface was observed by SEM. With the wet-bonding system, the shear bond strengths for the EDTA/NaOCl group, in which dentinal tubules openings and uniform resin tag penetration into dentinal tubules were observed, were significantly higher than the EDTA and control groups. With the self-etching system, the shear bond strengths were significantly lower in the EDTA group compared with the NaOCl and control groups. The effects of endodontic irrigation on the bonding of resin cement to radicular dentin depended on the dentin bonding system used.     

Effect of MTAD on flexural strength and modulus of elasticity of dentin

The purpose of this study was to evaluate the effect of MTAD on the flexural strength and modulus of elasticity of dentin. Dentin bars were randomly assigned to eight groups treated with various concentrations of NaOCl (5.25%, 2.65%, 1.31%, 0.66%), 17% EDTA, MTAD, saline, or according to a clinical protocol with 1.3% NaOCl and then 5 min of MTAD. Specimens were subjected to flexural strength and modulus of elasticity tests. Two-sample t test (alpha = 0.05) showed no statistically significant differences between various groups except for a reduction in flexural strength for the 2-h MTAD group (p = 0.002) and the EDTA group (p = 0.002). A significant reduction of modulus of elasticity for the 2-h MTAD group (p < 0.001), EDTA group (p < 0.001), and 0.6% NaOCl (p < 0.002) also was noted. There was no significant difference in flexural strength and modulus of elasticity between the dentin bars exposed to saline or MTAD when applied according to the clinical protocol (p > 0.05). These results indicate that MTAD can be used as prescribed for clinical use without affecting the physical properties of the dentin.     

Soft chelating irrigation protocol optimizes bonding quality of Resilon/Epiphany root fillings

This study was designed to test the impact of either a strong (MTAD) or a soft (1-hydroxyethylidene-1, 1-bisphosphonate [HEPB]) chelating solution on the bond strength of Resilon/Epiphany root fillings. Both 17% EDTA and the omission of a chelator in the irrigation protocol were used as reference treatments. Forty extracted human upper lateral incisors were prepared using different irrigation protocols (n = 10): G1: NaOCl, G2: NaOCl + 17% EDTA, G3: NaOCl + BioPure MTAD (Dentsply/Tulsa, Tulsa, OK), and G4: NaOCl + 18% HEPB. The teeth were obturated and then prepared for micropush-out assessment using root slices of 1 mm thickness. Loading was performed on a universal testing machine at a speed of 0.5 mm/min. One-way analysis of variance and Tukey multiple comparisons were used to compare the results among the experimental groups. EDTA- and MTAD-treated samples revealed intermediate bond strength (0.3-3.6 MPa). The lowest bond strengths were achieved in NaOCl-treated samples (0.3-1.2 MPa, p < 0.05). The highest bond strength was reached in the HEBP-treated samples (3.1-6.1 MPa, p < 0.05). Under the present in vitro conditions, the soft chelating irrigation protocol (18% HEBP) optimized the bonding quality of Resilon/Epiphany (Resilon Research LLC, Madison, CT) root fillings.     

Evaluation of the effect of MTAD in comparison with EDTA when employed as the final rinse on the shear bond strength of three endodontic sealers to dentine

The purpose of the study was to evaluate the effect of MTAD in comparison with EDTA as a final rinse on the shear bond strength of Kerr, Apexit and AH plus. Dentine surfaces of 135 extracted human non-carious maxillary premolars were divided into three groups (n = 45). Groups I and II were conditioned with 1.3% NaOCl for 20 min, followed by a final rinse of 17% EDTA for 1 min and MTAD for 5 min respectively. Group III was treated with distilled water. Each group was further divided into three subgroups (n = 15). Subgroup 1: Kerr, Subgroup 2: Apexit and Subgroup 3: AH plus. Three-millimetre-long sections of polyethylene tubes were filled with freshly mixed sealer and placed on the dentine surfaces. The bonding between the sealer and dentine surface was evaluated using shear bond testing. The values were statistically evaluated using one way anova followed by Tukey's test. Significant difference was found among the bond strength of the sealers and irrigating regimes. AH plus showed superior bond strength among the tested sealers, when EDTA was employed as the final rinse (P < 0.05). MTAD as a final rinse affected the bond strength of AH plus and Apexit, which were significantly lower than the control group.     

Application of biologically-oriented dentin bonding principles to the use of endodontic irrigants

PURPOSE: To compare the removal of smear layer and the structure of the hybrid layer formed after the use of EDTA or MTAD solutions when used as a final flush. METHODS: Single-rooted extracted premolars (n=18) were collected and treated for root canal therapy using NaOCl irrigation followed by a final rinse of 17% EDTA, Biopure MTAD, or saline (negative control). The roots were obturated with gutta-percha and a hydrophilic HEMA-containing root canal sealer. The TEM specimens were impregnated with 50% silver nitrate to visualize sealing imperfections and nanoleakage. The structure of the coronal, middle and apical parts of root canal walls was examined using transmission electron microscopy. RESULTS: After NaOCl irrigation, a final rinse with BioPure MTAD or 17% EDTA completely removed the 2 microm-thick smear layer on mechanically instrumented root canal walls. The BioPure MTAD hybrid layer was thicker than the 17% EDTA hybrid layer. Both the BioPure MTAD and EDTA caused a collapse of the dentin matrix structure which impeded sealer infiltration and the formation of high quality hybrid layer bonding. The hybrid layers created in smear layer-covered dentin exhibited less potential for nanoleakage than the MTAD or EDTA hybrid layers.     

The effects of sodium hypochlorite (5.25%), Chlorhexidine (2%), and Glyde File Prep on the bond strength of MTA-dentin

The purpose of this study was to evaluate the effects of sodium hypochlorite (5.25%), chlorhexidine (2%), and Glyde File Prep on the bond strengths of MTA-dentin in vitro. Standardized dentin disks were prepared and the central hole in each disk was filled with mineral trioxide aggregate (MTA). The specimens were randomly divided into four groups to be immersed in saline, 5.25% NaOCl, 2% chlorhexidine, and Glyde File Prep for 2 hours. The bond strengths of MTA-dentin were measured with a material testing system (MTS) and the fractured surfaces on the root walls were observed by scanning electron microscopy. Compared with the control group, the bond strengths were significantly lower in Glyde File Prep group (p < 0.05) and there was no significant difference in the chlorhexidine group or in the NaOCl group (p > 0.05). This study suggested that Glyde File Prep could negatively affect the bond strengths of MTA-dentin.     

The Effect of Endodontic Irrigants on the Microtensile Bond Strength of Dentin Adhesives

IntroductionThe purpose of this study was to evaluate the microtensile bond strength of a total etch (XP-Bond) and a self-etch (Clearfil SE Bond) adhesive system to dentine surfaces treated using endodontic irrigants.MethodsTwenty-four freshly extracted third molars were used. After creating a smear layer on the coronal midthird portion of the crowns, the teeth were divided into three groups and surfaces were irrigated with distilled water, 5.25% NaOCl + 17% EDTA, and 1.3% NaOCl + BioPure MTAD, respectively. Each group was divided into two subgroups, and a self-etching adhesive and an etch-and-rinse adhesive were applied respectively. The teeth were restored with a composite material and sectioned to produce sticks for microtensile bond testing.ResultsThe microtensile bond strength of the MTAD + Clearfil SE group was found to be significantly lower than the microtensile bond strength of the distilled water + Clearfil SE Bond group and the NaOCl, EDTA, + Clearfil SE Bond group (p = 0.0001, p = 0.009).ConclusionsBecause of the significant reduction of Clearfil SE Bond to coronal dentine after MTAD application, an etch-and rinse adhesive such as XP-Bond may be preferred if this irrigant has been chosen during endodontic treatment.     

Effect of medications for root canal treatment on bonding to root canal dentin

Use of resin-based restorative materials recently has become widely accepted for treatment of endodontically treated teeth. However, some solutions routinely used during endodontic treatment procedures may have an effect on bond strengths of adhesive materials to root canal dentin. The purpose of this in vitro study was to evaluate the effect of various medications on microtensile bond strength to root canal dentin. Fourteen extracted human single-rooted teeth were used. The crowns and the pulp tissues were removed. The root canals were then instrumented and widened to the same size. The teeth were randomly divided into seven groups of two teeth each. The root canal dentin walls of the roots were treated with 5% sodium hypochloride (NaOCI), 3% hydrogen peroxide (H2O2), the combination of H2O2 and NaOCl, or 0.2% chlorhexidine gluconate for 60 s; or calcium hydroxide or formocresol for 24 h. The teeth in control group were irrigated with water. The root canals were obturated using C&B Metabond. After 24 h of storage in distilled water, serial 1-mm-thick cross-sections were cut, and approximately 12 samples were obtained from each group. Microtensile bond strengths to root canal dentin were then measured by using an Instron machine. The data were recorded and expressed as MPa. The results indicated that NaOCI, H2O2, or a combination of NaOCl and H2O2 treatment decreased bond strength to root canal dentin significantly (p < 0.05). The teeth treated with chlorhexidine solution showed the highest bond strength values (p < 0.05). In conclusion, chlorhexidine is an appropriate irrigant solution for root canal treatment before adhesive post core applications.     

Effect of chemical irrigants on the bond strength of a self-etching adhesive to pulp chamber dentin

The aim of this study was to evaluate the influence of endodontic irrigants on adhesion to pulp chamber dentin. Seventy crowns of bovine incisors were cut to expose the pulp chamber. Specimens were divided into seven groups, according to the irrigant solution used: G1, 0.9% sodium chlorite (control); G2, 5.25% NaOCl; G3, 5.25% NaOCl + 17% EDTA; G4, 2% chlorhexidine solution; G5, 2% CHX solution + 17% EDTA; G6, 2% chlorhexidine in a gel base; and G7, 2% CHX gel + 17% EDTA. After irrigation, Clearfil SE Bond was applied to pulp chamber dentin, followed by Filtek Z250 composite. Six rectangular sticks were obtained from each specimen and dentin/resin interface was tested in tension. Bond strength means were analyzed by ANOVA and Tukey test. There was a significant decrease in bond strength associated to NaOCl, whereas chlorhexidine irrigation showed no effects on adhesion. It was concluded that endodontic irrigants affected differently bond strength to pulp chamber dentin.     

Bond Strength of Epiphany Sealer Prepared with Resinous Solvent

This study evaluated in vitro the bond strength of Epiphany sealer prepared with resinous solvent of Epiphany system (Thinning resin) by using a push-out test. Forty maxillary canines were sectioned transversally below the cementoenamel junction to provide 4-mm-thick dentin disks that were centered in aluminum rings and embedded in acrylic resin. Root canals were prepared with tapered diamond bur. Intraradicular dentin was treated with 1% NaOCl for 30 minutes, 17% ethylenediaminetetraacetic acid for 5 minutes, and flushed with distilled water for 1 minute. The specimens were randomly distributed into 4 groups (n = 10) according to the filling material: GI, Epiphany without photoactivation; GII, Epiphany prepared with solvent without photoactivation; GIII, Epiphany followed by photoactivation; and GIV, Epiphany prepared with solvent followed by photoactivation. After the setting time, the specimens were submitted to the push-out test. The highest mean value (14.91 ± 2.82 MPa) was obtained with Epiphany prepared with solvent followed by photoactivation (GIV), which was statistically different (P < .01) from the other groups. Groups I (8.15 ± 2.47 MPa), II (9.46 ± 2.38 MPa), and III (9.80 ± 2.51 MPa) had inferior bond strength values and were statistically similar among themselves (P > .01). The resinous solvent of Epiphany system increased the bond strength of Epiphany sealer to dentin walls when followed by photoactivation.     

Quantitative analysis of the solubilizing action of MTAD,sodium hypochlorite,and EDTA on bovine pulp and dentin

Necrotic bovine pulp and dentin were used in this study as model tissues to represent the organic and inorganic components of the smear layer present in instrumented root canals. The capabilities of endodontic irrigants to dissolve pulverized forms of these tissues were compared. Lyophilized tissue samples were mixed for 2 h at 37 degrees C with MTAD, three concentrations of sodium hypochlorite (NaOCl), 17% EDTA, or isotonic saline. Undissolved tissues were rinsed with water and lyophilized. The change in tissue weight after exposure to an irrigant was measured to quantify solubilization. The results showed that various concentrations of NaOCl removed organic components of pulp and dentin effectively. As pulp solubilizers 5.25% and 2.60% NaOCl were equal (>90%), and 5.25% NaOCl was capable of dissolving virtually the entire organic component of dentin. EDTA was capable of solubilizing inorganic material in dentin and organic material in pulp and likely also in dentin. It dissolved >70% of the dentin and >51% of the pulp. The solubilizing effects of MTAD on pulp and dentin were somewhat similar to those of EDTA. The major difference between the actions of these solutions was a high binding affinity of doxycycline present in MTAD for the dentin.     

Effect of calcium hydroxide intracanal dressing on the bond strength of a resin-based endodontic sealer

The aim of this in vitro study was to evaluate the bond strength of Epiphany resin-based sealer to dentin walls after placement of calcium hydroxide [Ca(OH)2] dressings. Fifteen extracted single-rooted human teeth were instrumented using 2.5% NaOCl + EDTA as irrigants. The teeth were randomly assigned to 3 groups (n=5), according to the intracanal dressing: G1= Ca(OH)2 + saline; G2= Ca(OH)2 + 2% chlorhexidine gluconate (CHX) gel; and G3= saline (control). After 10 days of storage in 100% humidity at 37 degrees C, the dressings were removed and the root canals were filled with Epiphany sealer. After additional 48 h of storage, the specimens were sectioned transversally into 2-mm-thick discs. Push-out tests were performed (1 mm/min, Instron 4411) and the maximum loads at failure were recorded in MPa. One-way ANOVA and Newman-Keuls tests showed a statistically significant decrease in bond strength when a Ca(OH)2 dressing was used before root canal filling with Epiphany (G1= 10.18 +/- 1.99 and G2= 9.98 +/- 2.97) compared to the control group (13.82 +/- 3.9) (p< 0.05). It may be concluded that the use of Ca(OH)2 as an intracanal dressing material affected the adhesion of Epiphany to the root canal walls, but even though the values were within the acceptable range found in the literature.     

Effect of MTAD on Enterococcus faecalis-contaminated root canals of extracted human teeth

The purpose of this investigation was to compare the antimicrobial effect of MTAD (a mixture of a tetracycline isomer, an acid, and a detergent) with that of NaOCl with and without EDTA. Eighty-five extracted human teeth were contaminated with Enterococcus faecalis for 4 weeks. After biomechanical instrumentation using 1.3% or 5.25% NaOCl as root canal irrigant, the root canal and the external surface of each tooth were exposed to a 5-min application of MTAD, 1.3% NaOCl, 5.25% NaOCl or a 1-min application of EDTA followed by irrigation with 5 ml of 1.3% NaOCl or 5.25% NaOCl. Teeth or dentin shavings were cultured to determine presence or absence of the test bacteria. Fisher's exact test showed that the combination of 1.3% NaOCl as a root canal irrigant and MTAD as a final rinse was significantly more effective against E. faecalis than the other regimens. The chi2 test showed no difference between the other regimens.     

Bond strength of different endodontic sealers to dentin: push-out test

Objective

The aim of this in vitro study was to evaluate the bond strength of different root canal sealers to dentin.

Material and Methods

Forty extracted single-rooted human teeth were examined and the coronal and middle thirds of the canals were prepared with a 1.50 mm post drill (FibreKor Post System, Pentron). The teeth were allocated in two experimental groups, irrigated with 2.5% NaOCl+17% EDTA or saline solution (control group) and instrumented using Race rotary files (FKG) to a size #40 at the working length. Then, the groups were divided into four subgroups and filled with Epiphany sealer (Group 1), EndoREZ (Group 2), AH26 (Group 3) and Grossman''s Sealer (Group 4). After 2 weeks of storage in 100% humidity at 37ºC, all teeth were sectioned transversally into 2-mm-thick discs. Push-out tests were performed at a cross-head speed of 1 mm/min using a universal testing machine. The maximum load at failure was recorded and expressed in MPa.

Results

Means (±SD) in root canals irrigated with 2.5% NaOCl and 17% EDTA were: G1 (21.6±6.0), G2 (15.2±3.7), G3 (14.6±4.5) and G4 (11.7±4.1).Two-way ANOVA and Tukey''s test showed the highest bond strength for the Epiphany''s group (p< 0.01) when compared to the other tested sealers. Saline solution decreased the values of bond-strength (p<0.05) for all sealers.

Conclusion

Epiphany sealer presented higher bond strength values to dentin in both irrigating protocols, and the use of 2.5% NaOCl and 17% EDTA increased the bond strength values for all sealers.     

In vitro evaluation of effect of various endodontic solutions on selected physical properties of white mineral trioxide aggregate

During endodontic therapy various irrigating solutions at different concentrations and duration are used. These chemical solutions may affect the setting reaction of mineral trioxide aggregate (MTA). The aim of this study was to evaluate the effect of sodium hypochlorite (NaOCl) (5.25%), chlorhexidine gluconate (CHX) (2%), ethylenediaminetetraacetic acid (EDTA) solution (17%) and BioPure MTAD on surface micro-hardness and flexural strength of white MTA. Twenty-five disk-shaped and 25 bar-shaped specimens were divided into five groups and were stored under distilled water, NaOCl (5.25%), chlorhexidine CHX (2%), EDTA solution (17%) and BioPure MTAD for 7 days. The micro-hardness of disk specimens was measured while the flexural strength was tested on bar specimens. EDTA and BioPure MTAD significantly reduced the hardness and flexural strength as compared with other groups. Under distilled water strength remained high; therefore, a final flush with distilled water before placement of MTA is advocated, especially if decalcifying agents are used during the clinical procedure.