Activity Of Calcium Hydroxide Research Articles

Antibacterial Effectiveness of Calcium Hydroxide Combined with Cresotin against Enterococcus faecalis

The goal of endodontic treatment is to prevent and control of pulp and periradicular infections. Calcium hydroxide has a beneficial biological property as an intracanal medicament and can be combined with cresotin to disinfect bacteria in root canals, especially Enterococcus faecalis (E. faecalis) which is the most frequently isolated strain in the root canals. The aim of this study was to investigate in vitro the antimicrobial activity of calcium hydroxide, cresotin, and combination calcium hydroxide and cresotin (Ca[OH]2+Cresotin, 1:1 and 1:2) against E. faecalis. Antibacterial activity was determined by the agar diffusion method. The test medicaments were placed inside the hole that made in the inoculated agar medium. The zone of growth inhibition was measured and recorded after incubation for each plate, and the result was analysed statistically with ANOVA. The in vitro antimicrobial effects of combination calcium hydroxide and cresotin (Ca[OH]2+Cresotin, 1:2) has more prominent antimicrobial activity than others, and calcium hydroxide is more effective than cresotin alone. The antimicrobial activity of combined calcium hydroxide and cresotin is more effective in killing E. faecalis in comparison to the other treatments.

Physicochemical properties and antimicrobial activity of calcium hydroxide pastes in association with other compounds

Aim: This study aimed to evaluate the pH, Ca2+ release, solubility, and antimicrobial activity of calcium hydroxide (Ca(OH)2) pastes in association with different substances. Methods: Sixty acrylic teeth (n=10) were filled with pastes that associated Ca(OH)2 with the following substances: benzalkonium chloride 5% (G1) and 50% (G2) both in propylene glycol, arnica glycolic extract (G3), green tea glycolic extract (G4), Calen/PMCC™ (G5), and Calen™ (G6). In the group G1 to G4 were used 1g of Ca(OH)2 powder with 0,8g of vehicle. pH and Ca2+ release was measured after 7, 15, and 30 days. For solubility, micro-CT was used immediately and at the periods of 7, 15, and 30 days. For the antimicrobial analysis, a biofilm of E. faecalis was induced in vitro on bovine dentin discs. Live/dead viability dye and confocal scanning microscopy were used. Results: The highest pH values occurred on the first 7 days, and the G6, G1, G3, and G5 presented the highest pH values at this period (P <0.05). Ca2+ release was higher in all groups at 7 days, with the highest values observed in G1, G5, and G6. The volume of all pastes showed no significant difference in the intragroup analysis at 7 and 15 days (P <0.05). G1 and G2 showed the highest antimicrobial action (P <0.05). For the biovolume, there was difference between the G6 and the other groups (P >0.05) with G1 presenting the lowest values. Conclusion: Benzalkonium chloride 5% increases the antimicrobial action of the Ca(OH2), without impairs physicochemical properties.

Side streams from the vegetable oil production as feedstock for surfactants and treir derivative technical systems

This work conducts a technical analysis of the current production and consumption of vegetable oils and some of the oily byproducts to determine the potential feedstock for the synthesis of non-food-competitive surfactants and surfactant-based systems. It defines the concentrated phosphatides (phosphatidic sludge) as no-/low- value streams, appropriately suited for chemical valorisation. The study further creates biobased surfactants by amidation of phosphatidic sludge derived from refinery of sunflower and rapeseed oils with monoethanolamine, N-(2-hydroxyethyl)ethylenediamine, or N,N’-bis(2-hydroxyethyl)ethylenediamine, under the action of calcium hydroxide as catalyst in excellent yields (95–98 %). Besides waste remediation, the use of phosphatides enabled to create the mixed surfactant compositions, comprising fatty acid alkanolamides and calcium glycerolphosphatides with improved solubility in organic non-polar solvents. With new surfactants, there have been created reversed emulsion systems, which can be potentially applied to the development and exploitation of gas and oil deposits are recommended for drilling wells, the disclosure of productive strata; perforation of wells and development of productive layers; blockage of gas, gas condensate and oil wells; elimination of manifestations and flow of gas in wells; limitation and elimination of waterways; cleaning of the hollow zone of wells and intensification of the inflow of hydrocarbon raw materials, which have been tested in laboratory and experimental industrial conditions, and a significant part of them have been introduced or tested on gas condensate fields. Creation of coordinated, effective and economical actions that should be formed in the state energy policy of Ukraine would facilitate the development of oil and gas companies, namely: increase of own oil and gas production; maximizing the potential of energy saving; diversification of external sources of supply; approximation of the parameters of the oil and gas industry to the norms and standards of the European Union.

Evaluación de la actividad antimicrobiana del hidróxido de calcio combinado con diferentes concentraciones de omeprazol frente a enterococcus faecalis

Evaluación de la actividad antimicrobiana del hidróxido de calcio combinado con diferentes concentraciones de omeprazol frente a enterococcus faecalis

Antimicrobial activity of calcium hydroxide associated with a new vehicle (Triethanolamine)

Objective: The aim of this study was to evaluate the antimicrobial effectiveness of calcium hydroxide associated with a two conventional (anesthetic liquid and olive oil) and a new vehicle (Triethanolamine). Material and methods: Initially, microorganisms were collected from four upper incisors presenting unsatisfactory root canal treatments and persistent apical periodontitis from the same patient using sterile absorbent paper cones placed inside the root canal following initial access and root filling removal. Next, they were grown in a BHI culture medium for 24 h. Afterwards, they were placed in 10 Petri dishes with 3 holes, where different formulations of the medications studied were placed. After 48 and 72 h, readings were taken of the growth inhibition halos. Results: After using Kruskal-Wallis test with significance level of 1% (? = 0.01) it was observed that, calcium hydroxide associated with Triethanolamine, produced results similar to those produced by the anesthetic liquid. Both combinations were superior to the association with olive oil. Conclusion: Considering the results of this in vitro study, it is possible to consider that Triethanolamine can be a viable alternative to be used as a vehicle associated with the calcium hydroxide.Keywords: Vehicles; Calcium hydroxide; Endodontics.

Comparative evaluation of the effect of proton pump inhibitors associated with calcium hydroxide on Enterococcus faecalis: An in vitro study

Introduction: The purpose of this in vitro study was to evaluate the concentration dependent effect of proton pump inhibitors on the action of calcium hydroxide against E. faecalis using a broth dilution study. Methods: Calcium hydroxide at a concentration of 16 mg/ml, pantoprazole and Lansoprazole at a concentration of 1 mg/ml made into dilutions of 6.25 and 25 μg/ml was incorporated into a broth containing E. faecalis and spectrophotometrically analysed at 630 nm at two time parameters of 12 hours and 24 hours. Results: At 12 hours there was statistically significant growth inhibition by group 5 (calcium hydroxide and lansoprazole 6.25 μg/ml). At 24 hours,the maximum Inhibition of E. faecalis was demonstrated by group 2 (calcium hydroxide and chlorhexidine 2%) and group 5 (calcium hydroxide and lansoprazole 6.25 μg/ml). Conclusion: Concentration dependent usage of proton pump inhibitors along with calcium hydroxide have potential in the eradication of persistent apical periodontitis.

Antimicrobial Activity of Nanoparticle Calcium Hydroxide against Enterococcus Faecalis: An In Vitro Study.

Enterococcus faecalis (E. faecalis) has the ability to invade the dentinal tubules and resist high pH levels. As a result, calcium hydroxide (CH) is not much effective on this bacterium. In theory, nanoparticle calcium hydroxide (NCH) has smaller size and high surface area that enables it to penetrate into the deeper layers of dentin and be more effective on E. faecalis. This in vitro study was designed to compare the antimicrobial activity of NCH and CH against E. faecalis. The antimicrobial activity of NCH against E. faecalis was evaluated by two independent tests: the minimum inhibitory concentration (MIC) of intracanal medicament and agar diffusion test (ADT). The efficiency of the medicament in dentinal tubules was evaluated on 23 human tooth blocks that were inoculated with E. faecalis. The tooth blocks were assigned to one control group (saline irrigation) and two experimental groups receiving CH and NCH as intracanal medication. The optical density in each group was assessed with spectrophotometer after collecting samples from dentin depths of 0, 200 and 400 µm. Data were analyzed by SPSS software ANOVA, Kruskal-Wallis and Dunnett's test. The MIC for NCH was 1/4 of the MIC for CH. NCH with distilled water (DW) produced the greatest inhibition zone in agar diffusion test. NCH had greater antimicrobial activity in dentin samples from depths of 200 and 400 µm compared to CH. The antimicrobial activity of NCH was superior to CH in culture medium. In dentinal tubules the efficacy of NCH was again better than CH on the 200- and 400-µm samples.

Lead removal from cathode ray tube glass by the action of calcium hydroxide and poly(vinyl chloride)

With the development of flat screen technology, the cathode ray tubes (CRTs) used in TV sets became obsolete, leaving huge amounts of lead-containing CRT glass for disposal. We developed a novel lead volatilization process in which PbCl2 was generated in the presence of poly(vinyl chloride) (PVC) as a chlorination agent and Ca(OH)2 as an HCl absorber. PVC was incinerated in air atmosphere and the resulting HCl was captured by Ca(OH)2 before exiting the reactor with the air flow. CaCl2 and Ca(OH)2 reacted with the lead glass forming volatile PbCl2 and crystalline Ca-silicates. Since the reactivity of lead glass with gaseous HCl is negligible, the presence of Ca(OH)2 was essential for the success of this method. At a temperature of 1000°C, a molar Cl/Pb ratio of 16, and a molar Ca/Si ratio of about 2, approximately 99.9% of the lead was volatilized, leaving a residue with a lead content of 140mgkg−1. The residual calcium silicate, with its low lead level, has the potential to be repurposed for other uses.

Antibacterial effect of calcium hydroxide combined with chlorhexidine on Enterococcus faecalis: a systematic review and meta-analysis.

ObjectiveEnterococcus faecalis (E. faecalis) is the most frequently isolated strain in failed endodontic therapy cases since it is resistant to calcium hydroxide (CH). Whether a combination of CH and chlorhexidine (CHX) is more effective than CH alone against E. faecalis is a matter of controversy. Thus, the aim of this study was to conduct a systematic review and meta-analysis of the literature.Material and MethodsA comprehensive search in PubMed, EMbase, EBSCOhost, The Cochrane Library, SciELO, and BBO databases, Clinical trials registers, Open Grey, and conference proceedings from the earliest available date to February 1, 2013 was carried out and the relevant articles were identified by two independent reviewers. Backward and forward search was performed and then inclusion and exclusion criteria were applied. The included studies were divided into "comparisons" according to the depth of sampling and dressing period of each medicament. Meta-analysis was performed using Stata software 10.0. The level of significance was set at 0.05.ResultsEighty-five studies were retrieved from databases and backward/forward searches. Fortyfive studies were considered as relevant (5 in vivo, 18 in vitro, 18 ex vivo, and 4 review articles). Nine studies were included for meta-analysis. Inter-observer agreement (Cohen kappa) was 0.93. The included studies were divided into 21 comparisons for meta-analysis. Chi-square test showed the comparisons were heterogeneous (p<0.001). Random effect model demonstrated no significant difference between CH/CHX mixture and CH alone in their effect on E. faecalis (p=0.115).ConclusionsAccording to the evidence available now, mixing CH with CHX does not significantly increase the antimicrobial activity of CH against E. faecalis. It appears that mixing CH with CHX does not improve its ex vivo antibacterial property as an intracanal medicament against E. faecalis. Further in vivo studies are necessary to confirm and correlate the findings of this study with the clinical outcomes.

Evidence of the protein content of bovine and human dental pulps by the action of endodontic irrigation solutions through electrophoretic patterns

Background: Sodium dodecyl sulfate polyacrylamide gel electrophoresis let to show the protein content of different tissues. Dental pulp contains connective tissue which is removed during the endodontic treatment. Many studies consider bovine rather than human pulp tissue because of its size. Aim: To evidence the protein content of bovine and human dental pulps and the action of endodontic irrigation solutions through electrophoretic patterns. Materials and Methods: Extracts of human and bovine dental pulps were prepared. Sodium hypochlorite, calcium hydroxide, chlorhexidine and ethylenediamine tetraacetic acid were used as irrigating solutions. Results: Bovine and human pulps have a small difference in two bands of proteins present between 74 kDa and 80 kDa. The denaturizing capacity of sodium hypochlorite and the washing action of calcium hydroxide and chlorhexidine were evidenced. Ethylenediamine tetraacetic acid solution was shown to contain proteins continuously during the endodontic root canal washing. Conclusions: Differences in pulp tissues and the action of irrigating solutions on their protein content would help on the understanding of the biological process of the endodontic treatment.

Evaluation of the antibacterial effect of calcium hydroxide in combination with three different vehicles: An in vitro study

Antimicrobial activity of interappointment intracanal medications is an important consideration in endodontics. Considering the fact that calcium hydroxide (CH) cannot sterilize the root canal system, completing its antimicrobial spectrum seems necessary. The aim of this study was to compare the antibacterial activity of CH combined with three different vehicles in root canal system. In this in vitro experimental study, 61 freshly extracted human single rooted teeth were used. After chemo-mechanical preparation, the teeth were dressed with CH in combination with: G1: Distilled water (DW); G2: 5.25% sodium hypochlorite; G3: 0.2% chlorhexidine solution. All teeth were mounted in a 2-chamber apparatus. After sterilization, the coronal chamber was exposed to bacteria and the apical chamber was filled with broth for 90 days. Leakage was recorded when turbidity was observed in broth. Mean times of leakage and turbidity percentage were recorded for each group. Data were analyzed by One Way ANOVA test (α=0.005). The highest mean time of contamination was for chorhexidine/CH combination (M=66.76 days), and the lowest was for DW/CH combination (M=40.29 days). Statistically significant difference was observed between G3 and G1 (P=0.042), but the difference between G2 and G3 (P=0.76) or G1 and G2 (P=0.18) were not significant. 88.23% of the samples of G1, 70.58% of G2, and 64.70% of G3 were contaminated after 3 months. As an intracanal medication, the chlorhexidine/CH combination had significantly more antibacterial activity than DW/CH combination.

In vitro antimicrobial activity of calcium hydroxide mixed with different vehicles against Enterococcus faecalis and Candida albicans

The purpose of this in vitro study was to investigate antimicrobial activity of calcium hydroxide (CH) in combination with glycerin, chlorhexidine gluconate (CHX), cetrimide, or distilled water against Enterococcus faecalis and Candida albicans. Standard holes in the cultivated agar plates were filled with one of the CH preparations and control agents. The zones of microbial inhibition were measured after incubation period. The CH preparations with glycerin and CHX demonstrated more antifungal activity than CH preparations with cetrimide and distilled water. The CH-glycerin preparations had no effect against E. faecalis, and CH-CHX preparation was the most effective medication. Antimicrobial activity of CH may change with the type of the vehicle and against different microorganisms. Enterococcus faecalis was more resistant than C. albicans to CH preparations.

PR 20 Longevity of antimicrobial activity of calcium hydroxide in vitro

PR 20 Longevity of antimicrobial activity of calcium hydroxide in vitro

On the action of calcium hydroxide against cultured cells

On the action of calcium hydroxide against cultured cells

The healing of phenolized pulp exposures

The healing process of exposed human dental pulps has been reported previously by us. In that study the healing process was observed under 2 widely used medicaments, calcium hydroxide and zinc oxidee eugenol. It was found that the superficial portion of the pulp in contact with the calcium hydroxide was rapidly necrotized; within 4 weeks healing took place beneath the necrotic area with the appearance of a new odontoblastic layer and a new dentine bridge. Zinc oxideeeugenol did not necrotize the pulp tissue; however, it elicited an inflammatory reaction, which persisted throughout the course of the experiment. Pulp healing did not occur under zinc oxideeeugenol during the 12 weeks of the study. The question then arose whether or not the necrotizing action of calcium hydroxide was instrumental in promoting pulp healing. Since phenol is an escharotic drug, would its necrotizing action produce the same type of helaing under other capping as observed under calcium hydroxide? Good clinical results have been reported by phenolizing exposed pulp tissue before capping. Some clinicians use phenol before treating vital pulps with calcium hydroxide; however, there is no experimental evidence to substantiate its use. The next question was whether the use of phenol would reduce or enhance the beneficial action of calcium hydroxide in the process of pulp healing. In order to answer these questions, our original

THE HYDRATION OF THE ALUMINATES OF CALCIUM: IV. HYDROTHERMAL REACTIONS OF TRICALCIUM ALUMINATE AND ITS HYDRATES

A study was made of the hydrothermal reactions of tricalcium aluminate and its hydrates between 120° and 350 °C. Homogeneous samples of the hexahydrate of tricalcium aluminate may be prepared by treatment of the aluminate or its hexagonal hydrate in saturated steam at temperatures up to 150 °C. At temperatures of 250 °C. and above, under conditions favouring rapid hydrolysis, such as the addition of water to the anhydrous aluminate or hydroaluminate before autoclaving and rapid elevation of the temperature of the autoclave, crystals of calcium hvdroxide and of a hydroaluminate of lower lime–alumina ratio appear, usually mixed with the isometric hexahydrate. The new hydroaluminate occurs as rectangular, elongated, prismatic plates of low birefringence, refractive index 1.627, and has a lime–alumina ratio probably lower than 1.5. The hexagonal hydrate of tricalcium aluminate gives on hydrothermal treatment a better yield of the low-limed hydroaluminate than does the anhydrous aluminate. Only partial hydrolysis of the hexahydrate was obtained under any of the conditions used, but the hexagonal hydrate, autoclaved for 12 hr. at 350 °C., gave products composed almost entirely of the rectangular plate hydroaluminate and calcium hydroxide. No free hydrated alumina was found in the hydrothermal products.The rectangular plate hydroaluminate of calcium may also be prepared by the action of calcium hydroxide on hydrated alumina in saturated steam at 350 °C. It is therefore a stable product under those conditions.At temperatures below 250 °C. birefringent crystalline material is also formed on autoclaving tricalcium aluminate or its hydrates under conditions favouring hydrolysis. The experimental evidence indicates that one of the products is the birefringent calcium hydroaluminate formed on autoclaving the lower calcium aluminates at temperatures of 105 to 150 °C. (5).Precast Portland cement concrete products, when subjected to steam-curing, normally contain an excess of water, and the conditions for the formation of these birefringent hydroaluminates of calcium are therefore present. The same applies to the commercial steam-curing of other materials containing free lime and hydrated alumina. The formation of these hydroaluminates may explain the peculiar effect on the tensile and compressive strength of mortar and concrete test pieces produced by hydrothermal treatment at temperatures above 150 °C. (9).

STUDIES UPON THE COPPER FUNGICIDES

SUMMARY The initial product of the interaction ol cupric sulphate and calcium hydroxide solutions, at ordinary temperatures, is the 4CuO. S03 basic sulphate. With amounts of calcium hydroxide in excess of 0–75 equivalent, the 4CuO. S03 salt is slowly decomposed with elimination of the sulphate radicle and the formation of a blue hydrated cupric oxide or cupric hydroxide, a product called, for convenience, the hydroxide. The cupric hydroxide formed retains, by adsorption, part of the sulphate radicle. Direct evidence by analysis of the precipitate, which might be considered to indicate the formation of a basic copper‐calcium complex, is therefore unreliable. In the analogous interaction of calcium hydroxide with cupric chloride, the formation of cupric hydroxide in the presence of amounts of calcium hydroxide in excess of 0–75 equivalent, is indicated by the dehydration of the precipitate to form nigger brown hydrated cupric oxide, and by the definite point of inflection on the hydrogen‐ion concentration curve which corresponds to equimolecular amounts of calcium hydroxide and cupric chloride. The hydrogen‐ion concentration curve for the cupric sulphate‐calcium hydroxide reaction shows that permanent alkalinity is not‐reached until equimolecular amounts of calcium hydroxide have been added. The cupric hydroxide, formed from the 4CuO.SO3 basic sulphate by the action of calcium hydroxide, is stabilised by adsorbed sulphate ions. If the adsorbed sulphate and excess calcium hydroxide be removed by continued washing with carbon dioxide‐free water, the Bordeaux mixture precipitate undergoes dehydration to form the nigger brown hydrated cupric oxide. Dehydration of the Bordeaux mixture precipitate when sprayed upon foliage, is therefore prevented by some chemical or physical change of the precipitate which occurs on drying. Dehydration is not prevented by physical changes which occur on drying. Carbon dioxide is a factor in the process whereby dehydration is prevented. It is suggested that the formation in situ of the protective copper‐containing deposit by the action, primarily, of carbon dioxide, accounts for the excellent adhesive properties of the Bordeaux mixture precipitate; that inertness towards the chemical changes which occur after spraying may be the cause of failure of some Bordeaux substitutes; that these changes may profoundly affect the value of sedimentation tests as criteria for the fungicidal efficiency of various Bordeaux mixtures.

The flocculation of soils. II

Three types of mechanism whereby clay is flocculated by electrolytes, are discussed.1. Normal or direct flocculation the mechanism of which is precisely that by which electrolytes coagulate electro-negative suspensoids. The isoelectric point theory of such flocculation is assumed in this paper. Experimental evidence is brought forward to show that iron and aluminium salts behave in this “normal” way.2. Indirect flocculation which takes place whenever the electrolyte reacts with the clay and thereby brings into solution from the clay other substances which cause flocculation. The action of some neutral salts and of acids is regarded as being largely indirect.3. Abnormal flocculation which is the result of a reaction between the added flocculant and the emulsoid surface of the clay particle. The action of calcium hydroxide is placed under this heading for reasons set forth in the earlier paper.Because of its obvious bearing on important agricultural operations, the action of calcium hydroxide on clay is considered more fully. The following are the salient points of that consideration:(i) Although it is reversible to carbonic acid the flocculation of clay by calcium hydroxide is not due to the formation of calcium carbonate. Several experimental results are set forth to show this, the chief is that barium and calcium hydroxides behave quite differently to carbonate and carbonic acid, and alike to clay.(ii) The action of calcium hydroxide on clay is an action on an “emulsoid gel surface” and not an action on a sol present in gross amount.(iii) The hydroxyl ion may perform at least two functions in its cooperation with the calcium ion in the flocculation of clay: (a) when added with or after the calcium ion it produces the alkalinity necessary for the reaction between calcium compounds and silica, etc., as discussed in the earlier paper; (b) when added before the calcium ion it not only produces this alkalinity but also peptizes the clay with the production of a greater amount of the emulsoid surface and a consequent increase in the rapidity of flocculation and the volume of the coagulum.(iv) Critical mixtures of clay and silt—in which neither wholly dominates the system—can be obtained by decantation at an appropriate time during the sedimentation of soil suspensions. It is shown experimentally that when the clay of such mixtures is flocculated more rapidly than the silt, the silt then becomes dominant; and that when the silt is flocculated, more rapidly than the clay, the clay then becomes dominant.(v) The different behaviour of “clay” and of “silt” to calcium hydroxide is not regarded as due to any essential difference in the structure cf these particles but as being determined by the ratio of the emulsoid surface to the core of the particle. In clay the surface dominates the system, in silt the core dominates the system.(vi) In very low concentrations the hydroxyl ion appears to behave normally and to militate against the flocculation of clay by calcium salts.(vii) Organic emulsoids may, in ordinary soils, be partly responsible for the anomalous action of calcium hydroxide on clay, but it is shown that calcium hydroxide exhibits that anomalous action on a deep subsoil clay containing no organic matter.