Assessment of genotoxic effect of maleic acid and EDTA: a comparative in vitro experimental study.

OBJECTIVES: This study aims to evaluate and compare the genotoxic and apoptotic effect of aqueous solutions of ethylenediaminetetraacetic acid (EDTA) with that of maleic acid (MA) using Chinese hamster lung fibroblast (V79) cells growing in vitro. MATERIALS AND METHODS: Exponentially growing V79 cells were treated with various concentrations of EDTA or MA alone for 30 min, and genotoxic effect was analyzed by micronucleus as well as comet assays and the type of cell death by apoptotic cell measurements using microscopic and flow cytometric methods. For all the experiments, H2O2 was used as a positive control. RESULTS: Treatment of V79 cells with H2O2 resulted in significantly (P < 0.001) increased micronuclei and levels of DNA damage, whereas, EDTA/MA alone treated cells did not show significant increase of MN frequencies and comet parameters even at their higher concentrations when compared with that of untreated control. V79 cells treated with EDTA/MA for 30 min showed a nonsignificant increase in the percentage of apoptotic and necrotic cells at their lower concentrations (0.025 and 0.05 % for EDTA and MA, respectively). However, at higher concentrations, i.e., >IC50 (0.1 and 0.5 %) for EDTA and MA resulted in increased number of apoptotic and necrotic cells when compared with the untreated group. CONCLUSIONS: This study clearly demonstrates that MA and EDTA are not potentially genotoxic agents and MA induced lesser apoptotic/necrotic death than that of EDTA at their clinically relevant doses. CLINICAL RELEVANCE: MA may have a better clinical acceptability with comparable smear layer removal ability. Hence, the results presented here might be an additional supporting evidence for the use of MA in endodontic practice.

Evaluation of chemical interactions of maleic acid with sodium hypochlorite and chlorhexidine gluconate.

INTRODUCTION: The elimination of microorganisms from the root canal system necessitates the use of combination of irrigating solutions to enhance their antimicrobial property. The combination of irrigants and their interaction sometimes could be detrimental to the outcome of the root canal therapy. The purposes of this study were (1) to evaluate the interaction between 7% maleic acid (MA) and 2% chlorhexidine gluconate solution (CHX) and to find out the availability of individual irrigant and (2) to determine the free available chlorine content when 7% MA was mixed with 2.5% sodium hypochlorite (NaOCl) solution. METHODS: Interaction between MA and CHX was assessed by high-performance liquid chromatography. Available chlorine content in NaOCl was evaluated by the standard iodine/thiosulfate titration method. RESULTS: It was observed that more than 90% free MA and CHX were available when MA was combined with CHX. It was also observed that there was no precipitate formation when 7% MA was mixed with 2% CHX. Available chlorine content decreased significantly in the MA/NaOCl mixture. CONCLUSIONS: There were no adverse interactions or precipitate formation observed when MA was combined with CHX, but the available chlorine content was reduced when NaOCl was mixed with MA.

In vitro antimicrobial activity of maleic acid and ethylenediaminetetraacetic acid on endodontic pathogens.

OBJECTIVE: The aim of this study was to evaluate the antimicrobial efficacy of 7% maleic acid (MA) and 17% ethylenediaminetetraacetic acid (EDTA) in elimination of Enterococcus faecalis, Candida albicans, and Staphylococcus aureus at different time intervals. STUDY DESIGN: Transfer culture of microbial strains were used for inoculum preparation and determination of time-kill assay. The viability counts of 7% MA and 17% EDTA suspensions were performed at 0, 2, 4, 6, 12, and 24 hours. Assay results were analyzed by determining number of strains that yielded log(10) CFU/mL of -1 compared with counts at 0 hours, for test medicaments at time intervals. Medicaments were considered to be microbicidal at a minimum inhibitory concentration that reduced original inoculum by >3 log(10) CFU/mL (99.9%) and microbiostatic if inoculum was reduced by <3 log(10) CFU/mL. Statistical analysis was performed using chi-square and Fisher exact tests as well as Friedman test for comparison of the time interval within the MA and EDTA groups. RESULTS: At all time intervals, there was no significant difference between MA and EDTA for all of the organisms (P > .05). However, within the MA and EDTA groups at various time intervals, there were significant differences (P < .001). CONCLUSIONS: Equivalent antimicrobial activity was observed by MA and EDTA against all of the organisms tested at various periods.

Evaluation of decalcifying effect of maleic acid and EDTA on root canal dentin using energy dispersive spectrometer.

OBJECTIVE: The aim of this study was to evaluate mineral contents of root canal dentin after treatment with 7% maleic acid (MA) or 17% EDTA. STUDY DESIGN: Thirty pieces of teeth were divided into 3 groups: 1) 17% EDTA; 2) 7% MA; and 3) saline. All specimens were treated for 0, 1, 5, 10, 15 minutes. Levels of calcium, phosphorus, magnesium, sodium, sulfur, and oxygen were measured using energy dispersive spectrometer. Data were analyzed using 1-way analysis of variance. Tukey honest significant difference and Bonferroni test were used for comparison between the groups and time periods. RESULTS: MA reduced maximum amount of calcium and phosphorus at all time intervals, but was significant only up to 5 minutes (P < .001). Oxygen, sulfur, and magnesium were decreased more with saline and least with MA (P < .001). Sodium was decreased more with MA and least with EDTA (P < .001). CONCLUSIONS: MA decalcifies the root dentin, with most calcium and phosphorus extracted during the first 5 minutes, compared with EDTA.

Evaluation of the effect of maleic acid and ethylenediaminetetraacetic acid on the microhardness and surface roughness of human root canal dentin.

INTRODUCTION: The aim of this in vitro study was to evaluate the effect of 7% maleic acid and 17% EDTA solutions on the microhardness and the surface roughness of human root canal dentin. METHODS: Forty-five extracted human maxillary central incisors were sectioned longitudinally into a total of 90 segments, were embedded in auto polymerizing acrylic resin, and were grounded flat with silicon carbide abrasive papers. Based on the test solutions used, samples were divided randomly into three groups: (1) the EDTA group, 1 mL of 17% EDTA for 1 minute (n = 30), (2) the maleic acid group, 1 mL of 7% maleic acid for 1 minute (n = 30), and (3) the control group, 1 mL of 0.9% saline for 1 minute (n = 30). Every group was then divided into two subgroups of 15 specimens each. In group 1a, 2a, and 3a, specimens were used to determine the microhardness of the root canal dentine in the coronal, middle, and apical third using Vicker's hardness tester. In groups 1b, 2b, and 3b, specimens were used for the determination of surface roughness of the root canal dentine using a roughness tester (Surtronic, Leicester, England). The data were statistically analyzed using the Kruskall Wallis and Mann Whitney U tests. RESULTS: There was no significant difference between EDTA and maleic acid in the reduction of microhardness. The increase in roughness was significantly greater with maleic acid when compared with EDTA. CONCLUSION: Maleic acid reduced the microhardness of root dentin similar to EDTA but increased the surface roughness significantly more than EDTA.

In vitro sustained release of calcium ions and pH maintenance from different vehicles containing calcium hydroxide.

INTRODUCTION: Calcium hydroxide is widely used as an intracanal medicament in endodontics. Its therapeutic effects depend on the dissociation of calcium hydroxide into calcium and hydroxyl ions, which, in turn, depends on the vehicle used. The purpose of this in vitro study was to evaluate the sustained release of calcium ions and the pH change of calcium hydroxide over a period of 30 days when formulated with propylene glycol, polyethylene glycol 6000, chitosan, and guar gum. METHODS: Various formulations were prepared and placed inside the root canals of human teeth and were suspended in glass vials containing distilled water. At specific time intervals, the calcium ion concentration was analyzed using an ultraviolet spectrophotometer. pH changes of the medium were measured at various time intervals up to 30 days. RESULTS: Results revealed that chitosan formulation showed the maximum sustained release of calcium ions compared with the other three formulations. All the formulations exhibited high alkaline pH upto 30 days. CONCLUSION: From the results of this in vitro study, it can be concluded that chitosan can be used as a promising vehicle for for the sustained release of calcium ions from the calcium hydroxide in the root canal system.

A comparative evaluation of postobturation apical seal following intracanal irrigation with maleic acid and EDTA: a dye leakage under vacuum study.

OBJECTIVE: The aim of the study was to evaluate the postobturation apical seal following irrigation with 7% maleic acid (MA) or 17% EDTA using dye leakage under vacuum method. STUDY DESIGN: Seventy single-rooted human anterior teeth were subjected to root canal instrumentation. Based on the final irrigating solution used, samples were divided into 3 groups: (1) 17% EDTA + 2.5% NaOCl, (2) 7% MA + 2.5% NaOCl, (3) 0.9% saline. Then samples were obturated and placed in 2% rhodamine B dye solution under vacuum pressure for 30 minutes and allowed to remain in the dye for 7 days. Samples were then longitudinally split and examined for dye leakage under stereomicroscope. Data were analyzed using the Kruskal-Wallis test. RESULTS: MA showed the least apical leakage compared with EDTA and saline. Saline showed maximum leakage. CONCLUSION: Final irrigation with 7% MA improved the postobturation apical seal compared with 17% EDTA.

Comparison of the efficacy of maleic acid and ethylenediaminetetraacetic acid in smear layer removal from instrumented human root canal: a scanning electron microscopic study.

INTRODUCTION: The aim of this study was to assess, by scanning electron microscopic (SEM) analysis, the ability of 17% EDTA and 7% maleic acid in the removal of the smear layer from the human root canal system. METHODS: Eighty single-rooted human anterior teeth were subjected to standardized root canal instrumentation (step-back technique) and were irrigated with 2.5% NaOCl after each instrument. Based on the final irrigating solution used, samples were divided randomly into three groups: (1) the EDTA group: 17% EDTA+ 2.5% NaOCl (n = 30), (2) the maleic acid group: 7% maleic acid + 2.5% NaOCl (n = 30), and (3) the control group: 0.9% saline (n = 20). After final irrigation, teeth were prepared for SEM analysis to evaluate the cleaning of the coronal, middle, and apical thirds of radicular dentin by determining the presence or absence of smear layer. The data was statistically analyzed using the Kruskall-Wallis test. RESULTS: At the coronal and middle thirds, there was no significant difference between EDTA and maleic acid. Both were equally efficient in the removal of smear layer. In the apical third, maleic acid showed significantly better smear layer removing ability than EDTA. CONCLUSION: Final irrigation with 7% maleic acid is more efficient than 17%EDTA in the removal of smear layer from the apical third of the root canal system, which is a crucial area for disinfection.