EDTA inhibits in vitro substrate adherence capacity of macrophages: endodontic implications

The antimicrobial and immunomodulatory effects of Ionophores for the treatment of human infection

Ionophores are a diverse class of synthetic and naturally occurring ion transporter compounds which demonstrate both direct and in-direct antimicrobial properties against a broad panel of bacterial, fungal, viral and parasitic pathogens. In addition, ionophores can regulate the host-immune response during communicable and non-communicable disease states. Although the clinical use of ionophores such as Amphotericin B, Bedaquiline and Ivermectin highlight the utility of ionophores in modern medicine, for many other ionophore compounds issues surrounding toxicity, bioavailability or lack of in vivo efficacy studies have hindered clinical development. The antimicrobial and immunomodulating properties of a range of compounds with characteristics of ionophores remain largely unexplored. As such, ionophores remain a latent therapeutic avenue to address both the global burden of antimicrobial resistance, and the unmet clinical need for new antimicrobial therapies. This review will provide an overview of the broad-spectrum antimicrobial and immunomodulatory properties of ionophores, and their potential uses in clinical medicine for combatting infection.

Pure platelet-rich plasma and supernatant of calcium-activated P-PRP induce different phenotypes of human macrophages

AIM

This study aimed to evaluate the effect of two platelet preparations used in the clinic, pure platelet-rich plasma (P-PRP) and the supernatant of calcium-activated P-PRP (S-PRP), on the phenotype of human macrophages.

MATERIALS & METHODS

Surface markers and cytokine production of human monocyte-derived macrophages were analyzed after 24 h stimulation with P-PRP or S-PRP.

RESULTS

P-PRP and S-PRP present no difference in the expression of CD206, a M2 tissue-repair macrophage-related marker. However, these same macrophages presented different levels of CD163, CD86 as well as different IL-10 secretion capacities after 24 h incubation.

CONCLUSION

These platelet preparations do not have an equivalent biological effect over macrophages, which suggest that they may present different clinical regenerative potentials.

Effectiveness of Three Different Irrigants - 17% Ethylenediaminetetraacetic Acid, Q-MIX, and Phytic Acid in Smear Layer Removal: A Comparative Scanning Electron Microscope Study

Background:

Removal of smear layer from the root canal walls is important for long-standing endodontic success.

Aim:

The aim of this study is to evaluate and compare smear layer removing ability among 17% ethylenediaminetetraacetic acid (EDTA), Q-MIX, and phytic acid by scanning electron microscopy (SEM).

Materials and Methods:

This in-vitro experimental study assessed smear layer removal using three different irrigants. Thirty single-rooted freshly extracted human permanent premolars were collected, disinfected, and decoronated to a standardized root length of 13 mm. Root canals were cleaned and shaped till F2 universal rotary protaper at working length 1 mm short of the apex. They were randomly divided into three groups, and final irrigation was done accordingly. Group 1 (n = 10): with 1 ml of 17% EDTA, Group 2 (n = 10): with 1 ml of Q-MIX, Group 3 (n = 10): with 1 ml of phytic acid. Samples were then longitudinally sectioned and evaluated under SEM at coronal, middle, and apical levels.

Statistical Analysis:

Two-way analysis of variance and Tukey's post hoc test were performed. The level of significance was set at 0.05.

Results:

Smear layer removing ability among irrigants and sections in descending order: 17 EDTA > Q-MIX > phytic acid; coronal > middle > apical.

Conclusion:

17% EDTA showed better and promising results followed by Q-MIX and then phytic acid.

Classification of agents using Syrian hamster embryo (SHE) cell transformation assay (CTA) with ATR-FTIR spectroscopy and multivariate analysis

The Syrian hamster embryo (SHE) cell transformation assay (pH 6.7) has a reported sensitivity of 87% and specificity of 83%, and an overall concordance of 85% with in vivo rodent bioassay data. To date, the SHE assay is the only in vitro assay that exhibits multistage carcinogenicity. The assay uses morphological transformation, the first stage towards neoplasm, as an endpoint to predict the carcinogenic potential of a test agent. However, scoring of morphologically transformed SHE cells is subjective. We treated SHE cells grown on low-E reflective slides with 2,6-diaminotoluene, N-nitroso-N-ethylnitroguanidine, N-nitroso-N-methylurea, N-nitroso-N-ethylurea, EDTA, dimethyl sulphoxide (DMSO; vehicle control), methyl methanesulfonate, benzo[e]pyrene, mitomycin C, ethyl methanesulfonate, ampicillin or five different concentrations of benzo[a]pyrene. Macroscopically visible SHE colonies were located on the slides and interrogated using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy acquiring five spectra per colony. The acquired IR data were analysed using Fisher's linear discriminant analysis (LDA) followed by principal component analysis (PCA)-LDA cluster vectors to extract major and minor discriminating wavenumbers for each treatment class. Each test agent vs. DMSO and treatment-induced transformed cells vs. corresponding non-transformed were classified by a unique combination of major and minor discriminating wavenumbers. Alterations associated with Amide I, Amide II, lipids and nucleic acids appear to be important in segregation of classes. Our findings suggest that a biophysical approach of ATR-FTIR spectroscopy with multivariate analysis could facilitate a more objective interrogation of SHE cells towards scoring for transformation and ultimately employing the assay for risk assessment of test agents.

Ethylenediaminetetraacetic acid in endodontics

Ethylenediaminetetraacetic acid (EDTA) is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a polyamino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. It is produced as several salts, notably disodium EDTA and calcium disodium EDTA. EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. A review of the literature and a discussion of the different indications and considerations for its usage are presented.

Evaluation of biocompatibility of a new root canal irrigant Q Mix™ 2 in 1- An in vivo study

Aim:

To evaluate the biocompatibility of a new root canal irrigant Q mix™ 2 in 1 in comparison to 0.9% sterile saline, 3% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), and 17% ethylenediaminetetraacetic acid (EDTA).

Materials and Methods:

Six circles were drawn on the dorsal skin of 24 male Wistar Albino rats, leaving 2cm between each circle. Using a syringe, 0.1mL of each root canal irrigant was injected subcutaneously into five circles. In the sixth circle, the needle of an empty syringe was introduced into the skin, but no irrigant was injected (control group). Evaluations were done at 2 hours, 48 hours, 14 days, and 30 days postprocedure. Tissue samples were excised, embedded in paraffin blocks, and 3 μm thick sections were obtained and stained with hematoxylin and eosin. The areas of inflammatory reaction were evaluated. From each tissue sample, five sections presenting the greatest inflammatory reactions were examined under a light microscope, and analyzed statistically by analysis of variance (ANOVA) and Tukey's test.

Results:

At the two-hour examination period, all the irrigants showed a slight increase in the number of inflammatory cells, at 48 hours, the number of inflammatory cells were increased significantly, and after 14 and 30 days, they were decreased gradually. Qmix™ 2 in 1 showed a smaller number of inflammatory cells than other irrigants tested.

Conclusion:

QMix™ 2 in 1 was shown to be less toxic to the rat subcutaneous tissue than 3% NaOCl, 2% CHX, and 17% EDTA.

Inferior alveolar nerve paresthesia after overfilling of endodontic sealer into the mandibular canal

The present study describes a case of endodontic sealer (AH Plus) penetration within and along the mandibular canal from the periapical zone of a lower second molar after endodontic treatment. The clinical manifestations comprised anesthesia of the left side of the lower lip, paresthesia and anesthesia of the gums in the third quadrant, and paresthesia and anesthesia of the left mental nerve, appearing immediately after endodontic treatment. The paresthesia and anesthesia of the lip and gums were seen to decrease, but the mental nerve paresthesia and anesthesia persisted after 3.5 years. This case illustrates the need to expend great care with all endodontic techniques when performing nonsurgical root canal therapy, especially when the root apices are in close proximity to vital anatomic structures such as the inferior alveolar canal.

The role of ethylenediamine tetraacetic acid (EDTA) as in vitro anticoagulant for diagnostic purposes

Anticoagulants are used to prevent clot formation both in vitro and in vivo. In the specific field of in vitro diagnostics, anticoagulants are commonly added to collection tubes either to maintain blood in the fluid state for hematological testing or to obtain suitable plasma for coagulation and clinical chemistry analyses. Unfortunately, no universal anticoagulant that could be used for evaluation of several laboratory parameters in a sample from a single test tube is available so far. Ethylenediamine tetraacetic acid (EDTA) is a polyprotic acid containing four carboxylic acid groups and two amine groups with lone-pair electrons that chelate calcium and several other metal ions. Calcium is necessary for a wide range of enzyme reactions of the coagulation cascade and its removal irreversibly prevents blood clotting within the collection tube. Historically, EDTA has been recommended as the anticoagulant of choice for hematological testing because it allows the best preservation of cellular components and morphology of blood cells. The remarkable expansion in laboratory test volume and complexity over recent decades has amplified the potential spectrum of applications for this anticoagulant, which can be used to stabilize blood for a variety of traditional and innovative tests. Specific data on the behavior of EDTA as an anticoagulant in hematology, including possible pitfalls, are presented. The use of EDTA for measuring cytokines, protein and peptides, and cardiac markers is described, with an outline of the protection of labile molecules provided by this anticoagulant. The use of EDTA in proteomics and in general clinical chemistry is also described in comparison with other anticoagulants and with serum samples. Finally, the possible uses of alternative anticoagulants instead of EDTA and the potential use of a universal anticoagulant are illustrated.

Cytotoxicity analysis of EDTA and citric acid applied on murine resident macrophages culture

AIM

To assess the ex vivo cytotoxicity of EDTA and citric acid solutions on macrophages.

METHODOLOGY

The cytotoxicity of 17% EDTA and 15% citric acid was evaluated on murine macrophage cultures using MTT-Tetrazolium method [3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide]. A total of 5 x 10(5) cells were plated in medium culture with 17% EDTA or 15% citric acid. Fresh medium was used as a control. Toxicity values were analysed statistically by anova and Tukey's test (P<0.05) at short (0, 6, 12, 24 h) and medium periods (1, 3, 5, 7 days), using ELISA absorbance.

RESULTS

On the short term, both EDTA (0.253 nm) and citric acid (0.260 nm) exhibited cytotoxic effects on macrophage cultures (P<0.05). On the medium term, statistical differences were observed (P<0.05) between the groups. EDTA (0.158 nm) and citric acid (0.219 nm) were cytotoxic when compared with the control group; EDTA-reduced macrophage viability significantly more than citric acid (P<0.05).

CONCLUSIONS

Both EDTA and citric acid had effects on macrophages cells ex vivo, but citric acid was less toxic in periods from 1 to 7 days of use.

A scanning electron microscopic evaluation of different root canal irrigation regimens

The purpose of this study was to assess the effectiveness of endodontic irrigants in removing the smear layer from instrumented root canal walls using Scanning Electron Microscopy (SEM). The endodontic irrigants used were: 1% sodium hypochlorite (NaOCl); 1% NaOCl mixed to 17% EDTAC; 2% chlorhexidine gel; and Ricinus communis gel. Photomicrographs of the middle and apical thirds were evaluated with the aid of the Fotoscore - v. 2.0 software. The results indicated that the mixture of sodium hypochlorite and EDTAC completely removed the smear layer from dentinal walls. The other endodontic irrigants were not as efficient in cleansing the root canals.

In vitro evaluation of macrophage viability after incubation in orange oil, eucalyptol, and chloroform

OBJECTIVE

The aim of this study was to evaluate the cytotoxicity of orange oil, eucalyptol, and chloroform in a cell culture assay by using peritoneal macrophages from Swiss mice.

STUDY DESIGN

Control (Dulbecco's modified Eagle's medium [DMEM] plus 1.25% ethyl alcohol) and experimental (orange oil, eucalyptol, and chloroform) groups were studied. Solvents used were tested at 0.025% and 0.050% concentrations in DMEM plus 1.25% ethyl alcohol.

RESULTS

Orange oil, eucalyptol, and chloroform were all cytotoxic in comparison to the control group (P < .001). Orange oil showed the least cytotoxicity (P < .001). No significant differences were observed regarding cell viability when comparing the eucalyptol and chloroform groups (P < .05). There were significant differences in the cytotoxicity of eucalyptol and chloroform with an increase in concentration (P < .0001). Nevertheless, this difference was not significant in the orange oil group (P < .05).

CONCLUSION

Orange oil was less cytotoxic than eucalyptol and chloroform.

In vitro evaluation of the cytotoxic effects of acid solutions used as canal irrigants

Solutions of EDTA and citric acid have been used as canal irrigants. These substances must be compatible with apical periodontal tissue. The aim of this study was to evaluate comparatively the cytotoxicity of a 17% EDTA solution and that of three solutions with different concentrations of citric acid (10, 15, and 25%) on cultured fibroblasts. The solutions were diluted to 0.1% and 0.5% in culture medium and then applied to NIH 3T3 cells. After 0, 6, 12, and 24 h (short-term assay; viability) and 1, 3, 5, and 7 days (long-term assay; survival), the cells were counted. The data were compared by ANOVA. In the short-term experiments, all solutions presented a percentage of cell viability similar to that of control cells, except for the 17% EDTA solution diluted to 0.5%. After the long-term assay, all groups presented a continuous and progressive cell growth except for the 17% EDTA solution and for the 25% citric acid solution at a 0.5% dilution. The citric acid solution did not impair cell growth and viability, proving to be noncytotoxic in vitro.

Biocompatibility of EDTA, EGTA and citric acid

This in vivo study evaluated, through the physicochemical assay method for quantification of enhanced vascular permeability, the irritating potential of EDTA, EGTA, citric acid and saline. Thirty-two male Wister rats were anesthetized and four experimental sites were demarcated on their backs. Injections of 2% Evans blue (20 mg/kg) were administered intravenously into the lateral caudal vein. The test solutions were immediately injected intradermally (0.01 mL) into the experimental sites. The animals were killed 30 min, 1, 3 and 6 h after injection of the solutions and each piece of skin was submerged in formamide and incubated at 45 masculineC for 72 h. After filtration, the optical density was measured in a spectrophotometer and the total amount of dye extracted from the samples was calculated by means of a standard calibration curve. Data were analyzed statistically by two-way ANOVA and Tukey's HSD test. Compared to control, EDTA had the greatest volume of dye followed by EGTA and citric acid, for all time periods. There were statistically significant differences between all solutions (p<0.01). Considering the periods assessed, a significant difference was observed between the 3- and 6-h groups (p<0.05), but not between the 30-min and 1-h groups. Among the organic acids evaluated in this study, citric acid yielded the lowest amount of extracted dye. This indicates that the citric acid was the least irritating solution.

Chelating agents in root canal treatment: mode of action and indications for their use

Chelating agents were introduced into endodontics as an aid for the preparation of narrow and calcified root canals in 1957 by Nygaard-Østby. A liquid solution of ethylenediaminetetraacetic acid (EDTA) was thought to chemically soften the root canal dentine and dissolve the smear layer, as well as to increase dentine permeability. Although the efficacy of EDTA preparations in softening root dentine has been debated, chelator preparations have regained popularity recently. Almost all manufacturers of nickel-titanium instruments recommend their use as a lubricant during rotary root canal preparation. Additionally, a final irrigation of the root canal with 15-17% EDTA solutions to dissolve the smear layer is recommended in many textbooks. This paper reviews the relevant literature on chelating agents, presents an overview of the chemical and pharmacological properties of EDTA preparations and makes recommendations for their clinical use.

In vitro inhibitory effect of EGTA on macrophage adhesion: endodontic implications

Ethylene glycol-bis-(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) is an specific calcium ion chelator proposed as endodontic irrigant. This study investigates the effect of EGTA on substrate adherence capacity of rat inflammatory macrophages. Inflammatory macrophages were obtained from Wistar rats and resuspended in RPMI-1640 medium. Substrate adherence capacity assays were carried out in Eppendorf tubes for 15 min of incubation at 37 degrees C in a humidified atmosphere of 5% CO2. The adherence index was calculated. Results showed that EGTA decreased substrate adherence capacity of inflammatory macrophages in a time- and dose-dependent manner. The EGTA concentration that caused half-maximal inhibition (IC50) was 202 +/- 32 mM (p < 0.01). EDTA was more potent than EGTA in inhibiting macrophage adherence (IC50 = 185 +/- 22 mM). Calcium chloride (10 mM) decreased the EGTA inhibitory effect on adherence index by 60.2% (p < 0.01). We conclude that EGTA significantly decreased substrate adherence capacity of macrophages.

Biocompatibility of dental materials used in contemporary endodontic therapy: a review. Part 1. Intracanal drugs and substances

Irrigation solutions and intracanal medicaments are used within the root canal to clean and aid in disinfecting the dentinal walls. Although these materials are intended to be contained within the root canal, they invariably contact the periapical tissues, either through inadvertent extrusion through the apex or leaching. This paper is a review on the methodology involved in biocompatibility testing followed by a discussion on biocompatibility of contemporary intracanal drugs and substances used in endodontics.

Comparative in-vitro evaluation of three chelator pastes

AIM

To compare the effect of three paste chelating agents on the root dentine of extracted teeth: Calcinase-Slide (lege artis, Dettenhausen, Germany), Glyde-File (DeTrey/Dentsply, Konstanz, Germany), RC-Prep (Premier, Norristown, USA).

METHODOLOGY

Ten slices of root dentine were covered with one of the chelating agents for 30 s, 1 min and 2 min and irrigated with 5 mL H2O2 and NaOCl. This was repeated five times. Pre- and postoperative Vickers hardness of root dentine was measured. Twenty slices of root dentine were covered with 0.1 mL of the chelating agents for 3, 6 and 9 min. Differences between pre- and postoperative weight were recorded. Ten root canals of extracted teeth were enlarged five ISO-sizes with 0.1 mL chelator paste for each file. The teeth were split longitudinally and cleanliness of the root-canal walls was evaluated under the SEM using a four-score evaluation index. Results were statistically analysed using the Wilcoxon-Mann-Whitney test, the Friedman test and the Kruskal-Wallis test with P<0.05 for all tests.

RESULTS

No significant differences between the chelating agents were found in terms of changes in dentine hardness. Loss of hardness increased significantly with increasing time of contact of the chelating pastes with dentine. There were significant differences between the three chelating agents and the control for loss of weight. After 3 min there was no significant difference between the chelating agents, after 6 and 9 min Calcinase-Slide showed significantly more weight loss than RC-Prep; after 6 min Glyde-File showed significantly more weight loss than RC-Prep. In the coronal and middle parts of the root canals, the cleaning ability of Calcinase-Slide was significantly better than of RC-Prep and Glyde-File; in the apical third no differences could be found.

CONCLUSIONS

Under the circumstances of this in vitro study, the three chelator pastes evaluated had no or only slight differences in terms of weight loss, changes of Vickers hardness in root dentine and cleanliness of root-canal walls. The use of a chelating agent may be useful to enhance cleanliness of the coronal and middle part of the root canal.

Cytotoxic effects of 10% citric acid and EDTA-T used as root canal irrigants: an in vitro analysis

EDTA-T and 10% citric acid used as root canal irrigants lead to more visible dentinal tubules than 5% sodium hypochlorite associated with 3% hydrogen peroxide. However, these cleansing agents must be compatible with apical periodontal tissue. We analyzed the cytotoxicity of 10% citric acid and EDTA-T in cultured fibroblasts using Trypan blue. The solutions were diluted to 1%, 0.1%, and 0.01% and applied to NIH 3T3 cell cultures. Cells grown on fresh DMEM served as a control. After 0, 6, 12, and 24 h (short-term assay, viability) and 1, 3, 5, and 7 days (long-term assay, survival), the cells were counted using a hemocytometer. In short-term tests, cell viability ranged from 85% to 99% for all experimental groups with no statistical differences when compared with control cultures, except for the group treated with 1% EDTA-T, which caused a progressive decrease in cell viability. In long-term tests, all cultures increased in number from day 1 to the end of the experimental period, showing no inhibition of cell proliferation, except for the cultures treated with 1% EDTA-T, which totally prevented cell growth. All dilutions of 10% citric acid were more biocompatible than EDTA-T. Cultures treated with citric acid had a higher percentage of viable cells in the short-term assays, and the cells retained their self-renewal capacity.

Comparative effects of two endodontic irrigants, chlorhexidine digluconate and sodium hypochlorite, on macrophage adhesion to plastic surfaces

This study was designed to compare the "in vitro" effect of chlorhexidine digluconate, proposed as a new irrigant solution, with sodium hypochlorite, the currently irrigant solution used to disinfect the root canal system before obturation of the canal, on substrate adherence capacity of macrophages. Inflammatory macrophages were obtained from Wistar rats and resuspended in RPMI-1640 medium. The adherence capacity of macrophages to a plastic surface was determined. Assays were conducted in Eppendorf tubes for 15 min of incubation at 37 degrees C in an humidified atmosphere of 5% CO2 in air. The adherence index was calculated. Chlorhexidine digluconate inhibited substrate adherence capacity of macrophages in all conditions tested. Half-maximal inhibition (IC50) was observed at 1:5.6 dilution. Chlorhexidine digluconate was less potent than 5.25% sodium hypochlorite (IC50 = 1:24.1 dilution) in inhibiting substrate adherence capacity of macrophages. Taking into account that substrate adherence is the first step in the phagocytic process of macrophages and in antigen presentation, chlorhexidine digluconate could inhibit macrophage function and modulate inflammatory reactions at the level of inflamed periapical tissues.

The effect of the bleaching agent sodium perborate on macrophage adhesion in vitro: implications in external cervical root resorption

The purpose of this study was to investigate the in vitro effect of sodium perborate, which is used as a bleaching agent in the treatment of discolored pulpless teeth, on substrate adherence capacity of macrophages. Inflammatory macrophages were obtained from Wistar rats and resuspended in RPMI-1640 medium. As a test of macrophage adhesion, the adherence capacity of macrophages to a plastic surface was determined. Assays were conducted in Eppendorf tubes for 15 min of incubation at 37 degrees C in a humidified atmosphere of 5% CO2. The adherence index was calculated. Results showed that sodium perborate decreased in a dose-dependent manner and decreased significantly (p < 0.05) the adherence index of rat peritoneal macrophages. Sodium perborate was less potent than sodium hypochlorite and eugenol in inhibiting macrophage adhesion. The inhibitory effect of sodium perborate on macrophage adhesion further supports the concept that this agent is not implicated in external cervical root resorption associated with intracoronal bleaching.

Effect of eugenol on macrophage adhesion in vitro to plastic surfaces

This study was performed to investigate the in vitro effect of eugenol on substrate adherence capacity of macrophages. Macrophages were obtained from Wistar rats. The adherence capacity of macrophages to the plastic surface of Eppendorf tubes was determined. Assays were carried out in these tubes for 15 min of incubation at 37 degrees C in a humidified atmosphere of 5% CO2 in air. Control peritoneal macrophages showed an adherence index = 52.5%. Eugenol decreased the adherence index of macrophages in a dose-dependent manner. A 1:1000 dilution of eugenol decreased the adherence index of macrophages by 16.6% (P < 0.05). Lower dilutions (1:100 and 1:10) greatly decreased the adherence index by 51% and 96.2% respectively (P < 0.01). Taking into account that substrate adherence is the first step in the phagocytic process of macrophages and in antigen presentation, eugenol could inhibit macrophage function and modulate immune and inflammatory reactions in dental pulp and periapical tissues.

In vitro effect of parachlorophenol and camphorated parachlorophenol on macrophages

The purpose of this study was to investigate the "in vitro" effect of parachlorophenol and camphorated parachlorophenol, used in endodontics for the disinfection of root canals, on the substrate adherence capacity of macrophages. Inflammatory macrophages were obtained from Wistar rats and resuspended in RPMI-1640 medium. As a test of macrophage phagocytic function, the adherence capacity of macrophages to a plastic surface was determined. Assays were conducted in Eppendorf tubes for 15 min of incubation at 37 degrees C in a humidified atmosphere of 5% CO2. The adherence index was calculated. Results showed that parachlorophenol and camphorated parachlorophenol significantly decreased the substrate adherence capacity of inflammatory macrophages. Taking into account that adhesion is the first step in the phagocytic process of macrophages and in antigen presentation, parachlorophenol and camphorated parachlorophenol could inhibit macrophage function and modulate immune and inflammatory reactions in periapical tissues.