Effect of continuous chelation on the dentinal tubule penetration of a calcium silicate-based root canal sealer: a confocal laser microscopy study.

BACKGROUND: This study aimed to evaluate the effect of various irrigation protocols on the penetration depth of a calcium silicate-based sealer into dentinal tubules using confocal laser scanning microscopy (CLSM). METHODS: Twenty single-rooted mandibular premolars were endodontically prepared and divided into the following two groups according to the irrigation protocol used (n = 10): Group I: NaOCl + EDTA and Group II: continuous chelation (NaOCl/Dual Rinse). Obturation was performed with the warm vertical compaction technique using TotalFill HiFlow bioceramic sealer mixed with a fluorophore dye. Samples were observed using CLSM at 10× to measure the percentage of sealer penetration and its maximum depth into the dentinal tubules. Data were analysed using one-way ANOVA followed by Tukey's post-hoc test. The significance level was set at p < 0.05 within all tests. RESULTS: Comparing the overall results of all sections tested, no statistically significant differences existed between the groups regarding the percentage of sealer penetration (p = 0.612) and maximum depth of penetration (p > 0.05). CONCLUSIONS: With both types of irrigation used, dentinal tubule penetration was higher in the coronal section than in the apical section. Continuous chelation using NaOCl/Dual Rinse HEDP performed better in the coronal segments, while irrigation using NaOCl + EDTA promoted a higher percentage of sealer penetration in the apical segment.

Decomplexation of Cu-1-hydroxyethylidene-1,1-diphosphonic acid by a three-dimensional electrolysis system with activated biochar as particle electrodes.

The feasibility of decomplexation removal of typical contaminants in electroplating wastewater, complexed Cu(II) with 1-hydroxyethylidene-1,1-diphosphonic acid (Cu-HEDP), was first performed by a three-dimensional electrode reactor with activated biochar as particle electrodes. For the case of 50 mg/L Cu-HEDP, Cu(II) removal (90.7%) and PO43- conversion (34.9%) were achieved under the conditions of electric current 40 mA, initial pH 7, acid-treated almond shell biochar (AASB) addition 20 g/L, and reaction time 180 min, with second-order rate constants of 1.10 × 10-3 and 1.94 × 10-5 min-1 respectively. The growing chelating effect between Cu(II) and HEDP and the comprehensive actions of adsorptive accumulation, direct and indirect oxidation given by particle electrodes accounted for the enhanced removal of Cu-HEDP, even though the mineralization of HEDP was mainly dependent on anode oxidation. The performance attenuation of AASB particle electrodes was ascribed to the excessive consumption of oxygen-containing functionalities during the reaction, especially acidic carboxylic groups and quinones on particle electrodes, which decreased from 446.74 to 291.48 µmol/g, and 377.55 to 247.71 µmol/g, respectively. Based on the determination of adsorption behavior and indirect electrochemical oxidation mediated by in situ electrogenerated H2O2 and reactive oxygen species (e.g., •OH), a possible removal mechanism of Cu-HEDP by three-dimensional electrolysis was further proposed.

The response of dual-species bacterial biofilm to 2% and 5% NaOCl mixed with etidronic acid: A laboratory real-time evaluation using optical coherence tomography.

AIM: The addition of etidronic acid (HEDP) to sodium hypochlorite (NaOCl) could increase the antibiofilm potency of the irrigant, whilst maintaining the benefits of continuous chelation. Studies conducted so far have shown that mixing HEDP with NaOCl solutions of relatively low concentration does not compromise the antibiofilm efficacy of the irrigant. However, the working lifespan of NaOCl may decrease resulting in a reduction of its antibiofilm efficacy over time (efficiency). In this regard, continuous irrigant replenishment needs to be examined. This study investigated the response of a dual-species biofilm when challenged with 2% and 5% NaOCl mixed with HEDP for a prolonged timespan and under steady laminar flow. METHODOLOGY: Dual-species biofilms comprised of Streptococcus oralis J22 and Actinomyces naeslundii T14V-J1 were grown on human dentine discs in a constant depth film fermenter (CDFF) for 96 h. Biofilms were treated with 2% and 5% NaOCl, alone or mixed with HEDP. Irrigants were applied under steady laminar flow for 8 min. Biofilm response was evaluated by means of optical coherence tomography (OCT). Biofilm removal, biofilm disruption, rate of biofilm loss and disruption as well as bubble formation were assessed. One-way anova, Wilcoxon's signed-rank test and Kruskal-Wallis H test were performed for statistical analysis of the data. The level of significance was set at a ≤.05. RESULTS: Increasing NaOCl concentration resulted in increased biofilm removal and disruption, higher rate of biofilm loss and disruption and increased bubble formation. Mixing HEDP with NaOCl caused a delay in the antibiofilm action of the latter, without compromising its antibiofilm efficacy. CONCLUSIONS: NaOCl concentration dictates the biofilm response irrespective of the presence of HEDP. The addition of HEDP resulted in a delay in the antibiofilm action of NaOCl. This delay affects the efficiency, but not the efficacy of the irrigant over time.

Efficacy and safety of 188Re-HEDP in lung cancer patients with bone metastases: a randomized, multicenter, multiple-dose phase IIa study.

PURPOSE: To investigate the pain-relieving effect and safety of three different doses of 188Re-hydroxyethylidine diphosphonate (HEDP) in patients with lung cancer and bone metastases. METHODS: For this randomised, phase 2 and multicenter trial, we enrolled patients with lung carcinoma and multifocal bone metastases and excluded patients who had received bisphosphonates or external-beam radiotherapy within the previous 4 weeks. Fifty-four patients were randomized to receive a single injection of 188Re-HEDP, at doses of 30, 40 or 50 MBq/kg (interval, 12 weeks). Patients were followed-up by assessment of numerical rating scale (NRS) score, global quality of life (QOL) score and adverse events (AEs). ANOVA analysis, Chi-Squared test and LSD-t test were used in this study. RESULTS: Significantly decreased NRS scores relative to baseline were observed in 40 MBq/kg group (Week 0 vs. Week 12: 6.0 ± 1.4 vs. 4.8 ± 2.5, P = 0.033) and 50 MBq/kg group (Week 0 vs. Week 12: 5.5 ± 1.5 vs. 4.5 ± 2.9, P = 0.046). Significant change of global QOL score from baseline was observed in 40 MBq/kg group at week 8 (global QOL score: P = 0.024, pain score: P = 0.041) and 50 MBq/kg group (pain score: P = 0.021) at week 12. No patients withdrew trial because of AEs in three groups. CONCLUSIONS: 188Re-HEDP at dose of 40 and 50 MBq/kg was generally effective to alleviate pain and improve QOL in lung cancer patients with painful bone metastases. 188Re-HEDP was safe and well-tolerated.

Trace-level determination of phosphonates in liquid and solid phase of wastewater and environmental samples by IC-ESI-MS/MS.

Phosphonates are increasingly used as water-softening agents in detergents, care products, and industrial processes. Despite poor biodegradability, high removal rates during wastewater treatment (WWT) have been observed, owing to strong adsorption affinity to activated sludge and mineral surfaces. Due to phosphonates representing challenging analytes, no method for the compound-specific quantification of phosphonates from solid samples has hitherto been published. In order to improve the data foundation on the environmental fate of phosphonates, an analytical method based on anion exchange chromatography and detection by electrospray ionization coupled to tandem mass spectrometry (IC-ESI-MS/MS) was developed, allowing the trace quantification of phosphonates from surface water (LOQs between 0.04 and 0.16 µg/L), wastewater (LOQs between 0.6 and 2.3 µg/L), sediment and suspended matter of rivers (LOQ < 0.1 mg/kg), and suspended matter of wastewater (LOQ < 1 mg/kg). Specificity and selectivity were enhanced by the implementation of isotope-labeled internal phosphonate standards derived through synthesis. This study describes the development of a comprehensive tool set for the determination of aminotris(methylenephosphonic acid) (ATMP), diethylenetriaminepenta(methylenephosphonic acid) (DTPMP), ethylenediaminetetra(methylenephosphonic acid) (EDTMP), 1-hydroxyethanediphosphonic acid (HEDP), and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) during WWT and in the aqueous environment. In the investigated matrices, HEDP and PBTC were generally present in highest and EDTMP in lowest abundance. The phosphonate contents detected in river water were in the sub to low µg/L range, depending on the wastewater burden, whereas contents in the low to medium µg/L range were found in untreated wastewater. The loads of the solid phases exceeded the contents of the corresponding liquid phases by roughly three orders of magnitude. Current data imply that phosphonates undergo significant partitioning to the solid phase during WWT and in natural water bodies. Graphical abstract.

Cleanliness and erosion of root canal walls after irrigation with a new HEDP-based solution vs. traditional sodium hypochlorite followed by EDTA. A scanning electron microscope study.

OBJECTIVES: To compare the cleanliness and erosion of root canal walls after the use of a new HEDP (1-hydroxyethane-1,1-diphosphonic acid) -based irrigant with that achieved by irrigation with sodium hypochlorite followed by EDTA. MATERIALS AND METHODS: Forty recently extracted single-rooted teeth were prepared with ProTaper Next files to size X3, using either HEDP-containing 3% sodium hypochlorite, throughout the procedure (n = 20), or 3% sodium hypochlorite followed by a final rinse with 17% EDTA (n = 20), which were both applied with a syringe and needle. Ten additional teeth were prepared and irrigated with saline and served as negative controls. The teeth were split longitudinally and subjected to SEM evaluation for the presence of a smear layer, debris, and erosion of the root canal wall. The Pearson chi-square test was used to compare the results, and the level of significance was set at p < 0.05. RESULTS: In both groups, there were more cases with a smear layer in the apical third of the root canal than in the coronal third, but the groups did not differ from each other significantly (p = 0.545). The root canal walls in both groups were almost free of debris, showing no difference between the groups (p = 0.342). Moderate erosion of the root dentine was found in 10-26% of the cases in both groups, but severe erosion was detected in only one case in each of the groups, which did not differ significantly from each other (p = 0.606). CONCLUSION: Within the limitations of the present study, the HEDP-based irrigation solution did not differ from 3% sodium hypochlorite followed by EDTA in terms of cleanliness or the incidence of erosion of the canal wall. CLINICAL RELEVANCE: When used with syringe and needle irrigation, the new HEDP-based irrigant is convenient and safe but should not be expected to result in cleaner canal walls than 3% sodium hypochlorite followed by 17% EDTA.

Batch Studies of Phosphonate and Phosphate Adsorption on Granular Ferric Hydroxide (GFH) with Membrane Concentrate and Its Synthetic Replicas.

Phosphonates are widely used as antiscalants for softening processes in drinking water treatment. To prevent eutrophication and accumulation in the sediment, it is desirable to remove them from the membrane concentrate before they are discharged into receiving water bodies. This study describes batch experiments with synthetic solutions and real membrane concentrate, both in the presence of and absence of granular ferric hydroxide (GFH), to better understand the influence of ions on phosphonate and phosphate adsorption. To this end, experiments were conducted with six different phosphonates, using different molar Ca:phosphonate ratios. The calcium already contained in the GFH plays an essential role in the elimination process, as it can be re-dissolved, and, therefore, increase the molar Ca:phosphonate ratio. (Hydrogen-)carbonate ions had a competitive effect on the adsorption of phosphonates and phosphate, whereas the influence of sulfate and nitrate ions was negligible. Up to pH 8, the presence of CaII had a positive effect on adsorption, probably due to the formation of ternary complexes. At pH > 8, increased removal was observed, with either direct precipitation of Ca:phosphonate complexes or the presence of inorganic precipitates of calcium, magnesium, and phosphate serving as adsorbents for the phosphorus compounds. In addition, the presence of (hydrogen-)carbonate ions resulted in precipitation of CaCO3 and/or dolomite, which also acted as adsorbents for the phosphorus compounds.

Chemical, cytotoxic and genotoxic analysis of etidronate in sodium hypochlorite solution.

AIM: To test whether the incorporation of a chelation powder, etidronate, marketed for root canal irrigation (Dual Rinse HEDP) into a sodium hypochlorite (NaOCl) solution induced additional cytotoxic and genotoxic effects not observed with NaOCl alone. METHODOLOGY: Fresh and 24-h-old mixtures of 0.9 g of etidronate in 10 mL of 2.5% NaOCl were assessed for their basic chemical features including pH and the ability to chelate Ca2+ from hydroxylapatite. Pure NaOCl and phosphate-buffered saline (PBS) with/without etidronate served as control solutions. Cytotoxic and genotoxic effects of diluted solutions (1:10, 1:100, and 1:1000) were assessed on Chinese hamster lung fibroblast (V79) using the MTT, clonogenic and micronucleus assays, respectively. One-way ANOVA and Tukey's HSD test were applied with an alpha-type error of 5% (P < 0.05). RESULTS: In mixtures of NaOCl and etidronate, the free available chlorine was lost completely after 24 h, and the pH dropped by more than 3 units. However, the ability of the etidronate to chelate Ca2+ was maintained. The fresh mixtures of NaOCl and etidronate were not more toxic than NaOCl alone (P > 0.05), whilst the 24-h-old mixtures were less toxic (P < 0.05) and statistically similar to pure etidronate. Etidronate per se showed little cytotoxicity and no genotoxicity at the tested dilutions. CONCLUSIONS: The ability of the used etidronate, Dual Rinse HEDP, to chelate calcium is not affected by NaOCl. Cytotoxicity and genotoxicity of mixed solutions is dictated by the presence of free available chlorine therein.

Short-term storage stability of NaOCl solutions when combined with Dual Rinse HEDP.

AIM: To assess the stability of NaOCl solutions when combined with a novel product for clinical use, Dual Rinse HEDP, which contains etidronate (1-hydroxyethane 1,1-diphosphonate). METHODOLOGY: Mixtures of NaOCl solutions with Dual Rinse HEDP were prepared so that they initially contained 5.0%, 2.5% or 1.0% NaOCl and always 9.0% of dissolved Dual Rinse HEDP powder per total weight. NaOCl solutions alone were used as controls. The stability of these solutions over 8 h was assessed in transparent borosilicate glass bottles at ambient temperature (23 °C). Subsequently, the effects of heating (60 °C) or storing the solutions at 5 °C were studied in polypropylene syringes. NaOCl concentrations were measured by iodometric titration, that is free available chlorine contents. Experiments were performed in triplicate. RESULTS: In the glass bottles at 23 °C, the 5.0% NaOCl/9.0% Dual Rinse HEDP solution lost 20% of the available chlorine after 1 h, whilst the corresponding 2.5% NaOCl and 1.0% NaOCl solutions retained this relative amount of available chlorine for 2 and 4 h, respectively. Results obtained in the glass bottles were similar to those achieved in the syringes. Heating of the NaOCl/Dual Rinse HEDP mixtures had a detrimental effect on available chlorine, with a complete loss after 1 h. In contrast, storing the NaOCl/Dual Rinse HEDP mixtures in a refrigerator at 5 °C kept the available chlorine high for 7 h, with the expected loss after a further hour of storage at 23 °C. CONCLUSIONS: Initial NaOCl concentration and temperature both affected short-term storage stability of combined solutions containing Dual Rinse HEDP.

A randomised, phase II study of repeated rhenium-188-HEDP combined with docetaxel and prednisone versus docetaxel and prednisone alone in castration-resistant prostate cancer (CRPC) metastatic to bone; the Taxium II trial.

BACKGROUND: Rhenium-188-HEDP is a beta-emitting radiopharmaceutical used for palliation of metastatic bone pain. We investigated whether the addition of rhenium-188-HEDP to docetaxel/prednisone improved efficacy of chemotherapy in patients with CRPC. METHODS: Patients with progressive CRPC and osteoblastic bone metastases were randomised for first-line docetaxel 75 mg/m2 3-weekly plus prednisone with or without 2 injections of rhenium-188-HEDP after the third (40 MBq/kg) and after the sixth (20 MBq/kg) cycle of docetaxel. Primary endpoint was progression-free survival (PFS), defined as either PSA, radiographic or clinical progression. Patients were stratified by extent of bone metastases and hospital. RESULTS: Forty-two patients were randomised for standard treatment and 46 patients for combination therapy. Median number of cycles of docetaxel was 9 in the control group and 8 in the experimental group. Median follow-up was 18.4 months. Two patients from the experimental group did not start treatment after randomisation. In the intention to treat analysis no differences in PFS, survival and PSA became apparent between the two groups. In an exploratory per-protocol analysis median overall survival was significantly longer in the experimental group (33.8 months (95%CI 31.75-35.85)) than in the control group (21.0 months (95%CI 13.61-28.39); p 0.012). Also median PFS in patients with a baseline phosphatase >220U/L was significantly better with combination treatment (9.0 months (95%CI 3.92-14.08) versus 6.2 months (95%CI 3.08-9.32); log rank p 0.005). As expected, thrombocytopenia (grade I/II) was reported more frequently in the experimental group (25% versus 0%). CONCLUSION: Combined treatment with rhenium-188-HEDP and docetaxel did not prolong PFS in patients with CRPC. The observed survival benefit in the per-protocol analysis warrants further studies in the combined treatment of chemotherapy and radiopharmaceuticals.

Impact of final rinse with saline or alcohol solution on root canal sealability.

Endodontic irrigation protocols are not only used to clean and disinfect the root canal system, but also to condition the canal wall dentine for subsequent root filling. In this study we tested whether a final irrigation step with saline solution or 80% ethanol improved root canal sealabilty by two popular sealers, an epoxy resin (AH Plus) and a hydraulic calcium silicate cement-based product (BioRoot RCS). Root canals in extracted single-rooted human teeth were instrumented and filled with a matched gutta-percha cone and sealer. During instrumentation and prior to root filling, sealer-specific irrigation protocols were applied. These involved a combined sodium hypochlorite/1-hydroxyethylidene-1,1-diphosphonic acid application, which was followed by irrigation with ethylenediaminetetraacetic acid (EDTA) for AH Plus. Protocols were followed by a 5-ml ultimate rinse with saline solution or 80% ethanol. No such final rinse was the control (N = 9). Canals were then dried with matched paper points. One week after root filling and storage of the teeth at 37°C in a humid environment, Rhodamine B was used to trace leakage. Two-way ANOVA revealed that the type of sealer had a significant (P < 0.05) impact on apical dye penetration while the final rinse did not (P > 0.05). AH Plus provided the slightly better seal (P < 0.05). Leakage occurred between the sealer and the dentin with AH Plus, and between the sealer-to-dentin as well as the sealer-to-gutta-percha interface with BioRoot RCS. In summary and under current conditions, there was no benefit from applying saline or ethanol as an ultimate rinsing solution prior to drying the canal with matched paper points.

Effect of continuous vs sequential chelation on the mechanical properties of root dentin: An ex vivo study.

OBJECTIVES: To evaluate the mechanical properties of root canal dentin treated with sodium hypochlorite (NaOCl) in combination with hydroxyethylidene diphosphonic acid (HEDP) or ethylenediaminetetraacetic acid (EDTA). METHODS: For testing fracture resistance, 45 single-rooted teeth were instrumented and irrigated with NaOCl/HEDP, NaOCl/EDTA, or distilled water. Fifteen untreated teeth served as control. After obturation, specimens from the experimental groups were thermocycled, dynamically-loaded, and then statically-loaded in a universal testing machine until failure. For flexural strength analysis, 15 teeth were instrumented and irrigated with NaOCl/HEDP or NaOCl/EDTA. Root segments were sectioned into dentin bars and tested for flexural strength using a universal testing machine. For microhardness evaluation, 20 teeth were instrumented and irrigated with NaOCl/HEDP or NaOCl/EDTA. Dentin disks from the coronal-third of each root segment were prepared, one before and one after irrigation, for microhardness testing with a Knoop hardness tester. RESULTS: The highest fracture resistance was recorded in the untreated group, and the lowest in the EDTA group. Although the HEDP group had higher fracture resistance than the EDTA group, the distilled water group demonstrated even greater fracture resistance than the HEDP group. Specimens treated with HEDP had significantly higher flexural strength and microhardness values when compared with those treated with EDTA. CONCLUSION: The fracture resistance, flexural strength, and microhardness of root canal dentin were higher when root canals were irrigated with NaOCl/HEDP, when compared with NaOCl/EDTA. CLINICAL SIGNIFICANCE: Irrigating root canals with NaOCl combined with HEDP significantly improves the mechanical integrity of root canal dentin compared to the use of NaOCl with EDTA.

Root canal irrigants effect on the compressive strength and calcium ion release of Biodentine.

Compressive strength and calcium ion release are integral properties of Biodentine for its enhanced efficiency. The present study evaluated the effects of Dual Rinse HEDP (DR HEDP), ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl) on the calcium ion release and compressive strength of Biodentine. Eighty Biodentine specimens were moulded and randomly divided into four groups (n = 20). Samples in group 1 were treated with 17 % EDTA; group 2 with DR HEDP; group 3 with 2.5 % NaOCl; and group 4 with distilled water. Samples were immersed in 10 mL of the test solutions for 1 min. The mean concentration of the calcium ion released was measured using atomic absorption spectrophotometry. The remaining 40 samples were tested for their compressive strength. Significant differences were determined among all the irrigants tested for calcium ion release and compressive strength. Samples treated with NaOCl had the lowest calcium ion release, while samples treated with 17 % EDTA had the largest calcium ions. No significant differences were measured between DR HEDP or distilled water. For compressive strength, samples treated with 2.5 % NaOCl had the lowest strength, while the highest values were obtained with distilled water. There was a significant difference between DR HEDP and EDTA, in which EDTA reduced the compressive strength significantly more than DR HEDP. DR HEDP had less detrimental effect on the calcium ion release and compressive strength of Biodentine.

Peracetic acid application as an antimicrobial and its residual (HEDP): a holistic approach on the technological characteristics of chicken meat.

The most significant occurrence of food-borne diseases is due to Campylobacter and Salmonella contamination from chicken meat, and for this reason, strict regulations about strategies to improve the control of food pathogens are imposed by food safety authorities. Despite the efforts of poultry industry since the beginning of risk analysis and critical control point to reduce the burden of food-borne illness, technological barriers along the way are increasingly necessary to ensure safe food. The aim of this review was to carry out a scientific approach to the influence of peracetic acid (PAA) as an antimicrobial and its toxicological safety, in particular the stabilizer used in the formulation of PAA, 1-hydroxyethylidene 1,1-diphosphonic acid (HEDP), suggesting the possibility of researching the residual HEDP in meat, which would allow the approval of the PAA by the health authorities of several countries that still restrict it. This review also aims to ascertain the effectiveness of PAA, in different cuts and carcasses, by different application methods, comparing the effectiveness of this antimicrobial with other antimicrobials, and its exclusive or combined use, for the decontamination of poultry carcasses and raw parts. The literature results support the popularity of PAA as an effective intervention against pathogenic bacteria during poultry processing.

Novel standard biodegradation test for synthetic phosphonates.

Determination of biodegradation of synthetic phosphonates such as aminotris(methylenephosphonic acid) (ATMP), ethylenediamine tetra(methylenephosphonic acid) (EDTMP), or diethylenetriamine penta(methylenephosphonic acid) (DTPMP) is a great challenge. Commonly, ready biodegradability of organic substances is assessed by OECD 301 standard tests. However, due to the chemical imbalance of carbon to phosphorus synthetic phosphonates do not promote microbial growth and, thus, limiting its biodegradation. Therefore, standard OECD test methods are not always reliable to predict the real biodegradability of phosphonates. In the presented study, we report the development of a standardized batch system suitable to synthetic phosphonates such as ATMP, EDTMP, DTPMP and others. The novel standard batch test is applicable with pure strains, activated sludge from different wastewater treatment plants (i.e., municipal and industrial), and with tap water as inoculum. We optimized the required calcium and magnesium exposure levels as well as the amount of the start inoculum biomass. We demonstrated that our test also allows to determine several parameters including ortho-phosphate (o-PO43-), total phosphorus (TP), ammonium (NH4+) and total organic carbon (TOC). In addition, also LC/MS analyses of cell-free medium is applicable for determining the mother compounds and metabolites. We applied our optimized standardized batch with selected phosphonates and evidenced that the chemical structure has a major influence of the microbial growth rates. Thus, our novel batch test overcomes drawbacks of the OECD 301 test series for determination of easy biodegradability for stoichiometric imbalanced organic compounds such as phosphonates.

Effect of different chelating agents on the shear bond strength of calcium silicate-based cements to coronal dentin.

We evaluated the shear bond strength (SBS) of mineral trioxide aggregate (MTA) and Biodentine (BD) to coronal dentin after treatment with ethylenediaminetetraacetic acid (EDTA), phytic acid (IP6), or etidronic acid (HEDP). Sodium hypochlorite-treated dentin surfaces were randomly divided into four groups according to conditioning protocol namely, 17% EDTA, 2.5% IP6, 9% HEDP, or distilled water (DS). Specimens were further divided according to the type of cement placed on conditioned dentin and SBS was tested. The results showed that DS/MTA and IP6/MTA groups had the highest values, and there was no significant difference between these two groups. IP6/BD group showed a lower SBS value compared to IP6/MTA; however, this did not reach the level of significance. The BS to dentin was influenced by the type of calcium silicate material and chelating agent. IP6 either improved or maintained the bonding while EDTA and HEDP showed a negative or no influence effect.

Effect of the Controlled Delivery of Chelating Agents on the Pulp Tissue Dissolution Ability of Fresh Sodium Hypochlorite Solutions.

INTRODUCTION: The purpose of this study was to evaluate pulp tissue dissolution ability of sodium hypochlorite (NaOCl) when mixed with tetrasodic etidronate (Na4HEBP) and disodic ethylenediaminetetraacetate (Na2EDTA) under controlled flow. METHODS: Bovine pulp tissue was extracted from the lower incisors of 10 bovine jaws. Pulp specimens were standardized in size (1 × 3 × 10 mm), blotted dry, and weighed (initial weight [T0]: mean (SD) = 31.98 (1.18) mg). Specimens from the same jaw were randomly assigned to 2 control (n = 3 each) and 4 experimental groups (n = 10 each): NC (negative control/distilled water), PC (positive control/6%NaOCl), G1 (3%NaOCl), G2 (3%NaOCl-17% Na2EDTA), G3 (3%NaOCl-18% Na4HEBP), and G4 (3%NaOCl-9% Na4HEBP). Distilled water and NaOCl were provided using a delivery pump under a continuous controlled rate (1 mL/min). A second pump alternately delivered either Na2EDTA or Na4HEBP at the same rate with a 30-second programmed interval. Percentage of tissue weight loss was calculated at 2, 5, and 10 minutes (T2, T5, and T10) and compared among groups with analysis of variance. Free available chlorine and pH were controlled at T0 and T10. RESULTS: No tissue remained in PC at T5. No dissolution occurred in NC. There were no significant differences in the percentage of weight loss among experimental groups at any point of time. Some remnant tissue was found in G3 (1.4% ± 2.4) and G4 (1.6% ± 2.3) at T10, whereas nothing was left in G1 and G2. CONCLUSIONS: The controlled delivery of Na2EDTA and Na4HEBP did not alter tissue dissolution ability of NaOCl when fresh solutions were mixed in the root canal.

2D and 3D Erosion Landscape Analysis of Endodontic-Treated Teeth Using EDTA and HEDP as Chelating Agents: A High-Resolution Micro-Computed Tomographic Study.

This study aimed to assess the amount of erosion during activated endodontic irrigation with either HEDP or EDTA via high-resolution micro-computed tomography. Two root canals of twenty premolars were prepared with ProTaper Next and irrigated with sodium hypochlorite. Palatal canals, which served as control groups, were sealed, while buccal canals were further irrigated with either EDTA (n = 10) or HEDP (n = 10), which served as test groups. Micro-CT was performed to measure erosion depth. For 2D and 3D measurements, non-parametric repeated ANOVA measurements and post hoc tests were performed. 2D analysis showed highly significant differences between the case groups at each position of the root (p ≤ 0.01). The cervical and apical positions showed significant differences in the EDTA group (p = 0.03). The 3D analysis also showed significant differences between both chelating agents (p < 0.01) and the case and control groups (p = 0.01). The mean erosion depths in the cervical, middle, and apical thirds of the EDTA group were 45.75, 41.79, and 32.25 µm, and for the HEDP group were 20.25, 16.40, and 15.96 µm, respectively. HEDP seems to have a significantly less erosive effect. Different irrigation protocols with harsher conditions, as might be the case during endodontic retreatment, could be assessed with micro-CT.

Impact of Final Irrigation Protocol on the Push-Out Bond Strength of Two Types of Endodontic Sealers.

Aim: The aim of this study was to assess the impact of the final irrigation protocol on the push-out bond strength of calcium silicate-based sealers when compared to an epoxy resin-based sealer. Materials and Methods: Eighty-four single-rooted mandibular human premolars were shaped using the R25® instrument (Reciproc, VDW, Munich, Germany) and then divided into three subgroups of 28 roots each depending on the final irrigation protocol: EDTA (ethylene diamine tetra acetic acid) and NaOCl activation, Dual Rinse® HEDP (1-hydroxyethane 1,1-diphosphonate) activation or sodium hypochlorite (NaOCl) activation. Then, each subgroup was divided into two groups (14 each) according to the sealer used (AH Plus Jet® or Total Fill BC Sealer®) for single-cone obturation. Dislodgement resistance using a universal testing machine, samples' push-out bond strength and failure mode under magnification were determined. Results: EDTA/Total Fill BC Sealer® showed significantly greater values of push-out bond strength compared with HEDP/Total Fill BC Sealer® and NaOCl/AH Plus Jet®, with no statistical difference with EDTA/AH Plus Jet®, HEDP/AH Plus Jet® and NaOCl/Total Fill BC Sealer®, whereas HEDP/Total Fill BC Sealer® showed significantly lower values of push-out bond strength. The apical third demonstrated higher means of push-out bond strength compared with middle and apical thirds. The most common failure mode was cohesive but showed no statistical difference compared to other types. Conclusions: Irrigation solution and final irrigation protocol affect the adhesion of calcium silicate-based sealers.

The Impact of Laser-Activated and Conventional Irrigation Techniques on Sealer Penetration into Dentinal Tubules.

Objective: The present study was aimed at comparing the efficacy of 1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP) and ethylenediaminetetraacetic acid (EDTA) by using various final irrigation techniques on penetration of sealer. Background: Traditional irrigation of root canals with a syringe limits the ability of sealer penetration. Various irrigants and activation techniques, including sonic and ultrasonic devices and various kinds of lasers, have been introduced to improve penetration of sealers into dentinal tubules. Methods: One hundred mandibular premolars were selected. Final irrigation was performed with HEDP or EDTA by conventional syringe irrigation (CI), EndoActivator (EA), passive ultrasonic irrigation (PUI), photon-induced photoacoustic streaming (PIPS), and shock wave-enhanced emission photoacoustic streaming (SWEEPS) methods (n = 10). After obturation of root canals with the EndoSequence BC Sealer, samples were evaluated using a confocal laser scanning microscope (CLSM), which enabled measurement of the maximum depth, percentage, and penetration area. Tests performed for analysis included the Kruskal-Wallis H and Mann-Whitney U tests. Results: In the EA method, the penetration percentage achieved using HEDP was significantly higher than EDTA at both sections (p < 0.05). Irrespective of the final irrigation solution employed, the PUI, PIPS, and SWEEPS techniques exhibited greater tubule penetration values compared with the CI and EA techniques (p < 0.05). Conclusions: HEDP and EDTA showed similar effects on the amount of penetrated sealer into the dentinal tubules, and the PUI, PIPS and SWEEPS methods provided enhanced EndoSequence BC Sealer penetration compared with the CI and EA methods. This study was approved by the Near East University institutional review board (#2020/86-1225).