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PubMed1995

Effect of root canal filling materials containing calcium hydroxide on the alkalinity of root dentin.

The effect of root canal filling pastes containing calcium oxide resp. calcium hydroxide on the alkalinity of extracted human teeth was investigated using a colour indicator (cresol red). An aqueous suspension of calcium hydroxide (Pulpdent), which is normally used for temporary root canal filling, most consistently produced alkalinity. Removal of the smear layer following instrumentation of the root canal led to increased proportion of alkaline-positive spots in dentinal locations distant from the canal. A clearly smaller effect was found with a calcium salicylate cement (Sealapex) and an oil-paste (Gangraena Merz), both of which are available for definite root canal fillings. Following removal of the smear layer, these hard-setting preparations caused moderate alkalinity in dentin adjacent to the canal but no effect was observed in locations more distant from the canal. Neither at locations adjacent to nor distant from the root canal was alkalinity found when another calcium salicylate cement (Apexit) was used. Apparently the release of hydroxyl ions into root dentin from calcium hydroxide containing root canal filling materials is not solely influenced by the absolute amount of calcium hydroxide, but also depends on other ingredients which variably inhibit the release of these ions.

Binomial Distribution↗
PubMed1961

The use of tetramethylammonium hydroxide in the Zimmermann reaction.

The use of tetramethylammonium hydroxide (T.M.A.H.) in place of potassium hydroxide in the Zimmermann reaction has been investigated. Although various pure steroids have different colour equivalents, a comparison of the results of 17-ketosteroid and 17-hydroxycorticosteroid estimations on a series of urines showed that the differences for the two reagents were only small and may be ignored. Tetramethylammonium hydroxide has the considerable advantage over potassium hydroxide of stability and need not be prepared freshly. The correction procedures available are discussed.

17-Ketosteroids↗
PubMed1984

Intrapericardial instillation of sodium hydroxide: failure to produce pericardial symphysis.

Previously reported clinical studies have suggested sodium hydroxide as an effective agent in causing pleural symphysis. To explore the sclerosing potential of this agent, we instilled 0.5% sodium hydroxide into the pericardium of four dogs. Normal saline was instilled into the pericardium of one control dog. Echocardiograms, 24 hour EKG monitoring and intracardiac pressures were recorded. One dog was sacrificed at the end of 24 hours, another at the end of seven days and three other dogs were sacrificed at the end of 28 days. ST elevations and prolonged episodes of supra-ventricular and ventricular tachycardia were noted during and within 24 hours after the intrapericardial instillation of sodium hydroxide in all the dogs. No arrhythmias were noted in the control dog. None of the dogs showed pericardial symphysis. These results suggest that sodium hydroxide causes serious cardiac arrhythmias when instilled intrapericardially and is of limited value in causing pericardial symphysis.

Animals↗
PubMed2004

Apical seal of root canals with gutta-percha points with calcium hydroxide.

The objective of this research was to determine if gutta-percha points with calcium hydroxide [Ca(OH)2] improve the apical seal after root canal filling and if the master point does it alone. Human single recently extracted teeth were biomechanically prepared and the root canals filled by the lateral condensation technique with ZOE and gutta-percha points, with or without calcium hydroxide. The teeth were placed into a 2% methylene blue solution in a vacuum environment for 24 h after which they were processed for stereomicroscope evaluation. Better results were observed with the teeth filled with gutta-percha points with calcium hydroxide (p=0.01). We conclude that these new points make a better apical seal and that these results can also be obtained with the calcium hydroxide master point associated with regular ones (p=0.05).

Calcium Hydroxide↗
PubMed2004

Remineralization of carious dentin. I: in vitro microradiographic study in human teeth capped with calcium hydroxide.

The objective of this in vitro study was to evaluate a possible remineralization of human carious dentin by calcium hydroxide. Thirty-nine freshly extracted human permanent and deciduous carious teeth were split into two halves. One half was used as control and the other as experimental. In the latter, a cavity was prepared and the remaining bottom layer of demineralized dentin capped with chemically pure calcium hydroxide. The experimental samples were stored at 37 masculine C. Time intervals were 2, 4, 6, 8, 10 and 12 weeks. All tooth halves were sawed and ground to plano-parallel sections with a thickness varying from 75 to 117 microm. Qualitative microradiographs showed a qualitative increase in radiopacity of the calcium hydroxide treated samples. Quantitative microradiography showed a statistically significant increase in total mineral content in the experimental samples compared to the control samples. These results indicate an in vitro remineralization of carious dentin by calcium hydroxide.

Calcium Hydroxide↗
PubMed2001

[Aluminum hydroxide hydrogel to remove arsenic from water].

OBJECTIVE: To describe the making of and the preliminary results from an aluminum hydroxide hydrogel that, when added directly to water, can totally eliminate arsenic, regardless of the nature of the water and the oxidation state of the metalloid. METHODS: The raw materials used to make the aluminum hydroxide hydrogel were: hydrated aluminum sulfate (which is used to make water safe for drinking), calcium hypochlorite in powder form, ammonium hydroxide, and distilled water (when done at the laboratory scale), and water from inverse osmosis of the same or better quality than the distilled water (when done at a pilot scale). Quality control for the finished product consisted of determining its ability to adsorb arsenic and performing bacteriological tests to demonstrate its sterility. The product was used with water samples to which arsenic had been added in the laboratory and with water samples from the province of Tucumán, Argentina, with naturally occurring arsenic. To analyze the arsenic in the water the colorimetric silver diethyldithiocarbamate method was used. RESULTS: Using the hydrogel greatly reduced the amount of arsenic. Treating both the natural and laboratory-produced arsenical waters yielded arsenic concentrations under the limit (0.01 parts per million) that was detectable with the analytical method used. The bacteriological tests of the finished product indicated there were no viable bacteria. CONCLUSIONS: Using the aluminum hydroxide hydrogel produced the desired reduction in the arsenic concentration in the water. This method for removing arsenic is inexpensive and easy to use in scattered rural populations in areas having high arsenic levels and lacking drinkable water, as well as an adequate sanitary and electric-power infrastructure.

Aluminum Hydroxide↗
PubMed1977

Calcium hydroxide and potassium nitrate as desensitizing agents for hypersensitive root surfaces.

The purpose of this investigation was to evaluate calcium hydroxide and potassium nitrate individually as densensitizing agents for hypersensitive root surfaces. The apparatus used in the experiment to measure hypersensitivity was (a) a thermo-electric stimulating device to measure hot and cold stimulation quantitatively and (b) a mechanical stimulating device to measure scratch stimulation quantitatively. The conclusions drawn from the study were: 1. Calcium hydroxide was more consistently effective in decreasing sensitivity then was potassium nitrate or the control. 2. Calcium hydroxide as compared to the control was statistically (99% level of significance) more effective in reducing sensitivity to mechanical, hot and cold stimulation immediately and at the conclusion of the experiment (3 months). 3. It appears that calcium hydroxide could be used as a desensitizing agent initially following periodontal surgery to reduce pain from hypersensitive roots in order that proper oral hygiene could be reestablished.

Adult↗
PubMed2004

Influence of different vehicles on the pH of calcium hydroxide pastes.

The main known benefit of calcium hydroxide as an intracanal medicament lies in the bactericidal effect conferred by its pH. The objective of this work was to determine the influence of the vehicle on the pH of calcium hydroxide pastes after usage in patients and in vitro. The incisor root canals of 180 patients were instrumented and filled with calcium hydroxide pastes containing distilled water, chlorhexidine, propylene glycol, anesthetic solution, camphorated p-monochlorophenol and camphorated p-monochlorophenol-propylene glycol. The pH of the paste in the patients' root canals was measured at 7, 14 and 21 days. Similarly, pH was measured in vitro up to 21 days. The pH of all the pastes remained constant throughout the time periods assessed. The calcium hydroxide-water combination showed significantly higher pH values than the other pastes in clinical use. Comparative analysis showed that the pH values of the anesthetic solution, camphorated p-monochlorophenol and camphorated p-monochlorophenol-propylene glycol were significantly higher in vitro. The type of vehicle was shown to influence the final pH of the pastes. However, the alkalinity of all pastes was maintained over time under the experimental conditions.

Adult↗
PubMed2002

Root canal filling with calcium hydroxide using different techniques.

Several different techniques for placing calcium hydroxide into root canals have been proposed, such as amalgam carriers, vertical pluggers, McSpadden compactors, Lentulo drills, files and special syringes. Because correct filling of the root canal is necessary for calcium hydroxide paste to act effectively, the aim of this research was to study different techniques of root canal filling with calcium hydroxide pastes in dog teeth. The placement of calcium hydroxide with a file, absorbent paper points and vertical pluggers presented the lowest number of empty spaces in the three thirds of the root canal, followed by the Lentulo drill and the McSpadden compactor.

Animals↗
PubMed2003

[Accidental extrusion of calcium hydroxide-based pastes into periapical lesions].

Calcium hydroxide is a widely used material in endodontic treatment due to its high alkalinity and antimicrobial properties. It is thought to create a favourable environment for periradicular repair and healing, and to stimulate hard tissue formation. The aim of the present retrospective study was to evaluate the effect of accidental and voluminous overextensions of calcium hydroxide pastes into periapical lesions and tissues on the prognosis of periapical healing. It was seen that calcium hydroxide overextensions did not disfavour healing, none of the endodontic treatments failed but healing was delayed in the majority of cases and in a number of cases extrusion induced immediate flare-ups. Therefore the deliberate extrusion of calcium hydroxide into periapical tissues is not advocated.

Adolescent↗
PubMed2005

Low-concentration sodium hydroxide solution injection in normal liver parenchyma of rabbits.

BACKGROUND: Percutaneous ethanol injection has been widely used as a non-surgical therapy for liver cancer, but it has some shortcomings such as local diffusion and unequal permeation. This study was designed to observe the volume, controllability and completeness of necrosis after injection of low concentration sodium hydroxide in the normal liver parenchyma so as to assess its possibility in treatment of liver cancer instead of ethanol. METHODS: Twenty-seven New Zealand rabbits were divided randomly into 9 groups (Aa, Ab, Ac, Ba, Bb, Bc, Ca, Cb, and Cc) by a 3 x 3(three-by-three) factorial design, each consisting of 3 rabbits. Group A was given sodium hydroxide solution at a concentration of 5%, while B at 2.5% and C at 1% in liver parenchyma. Each group received three doses of the solution: a (0.2 ml), b (0.5 ml) and c (1.0 ml). Then another 3 rabbits as side-effect group were dropped with sodium hydroxide solution in their liver lobe space. Liver and renal function changes in all the rabbits were compared after injection with pre-injection. RESULTS: All the lesions were localized. At the concentration of 2.5% and 5%, the lesion volume increased with the dose increased from 0.2 ml to 1.0 ml (P<0.05). No significant differences were found in the lesion volume of the groups receiving the same dose but different concentration. Changes in liver and renal function were not significant 7 days after injection, compared with those before injection. CONCLUSIONS: 2.5% and 5% sodium hydroxide solution could control local complete necrosis in normal liver. With regard to safety, 2.5% alkali solution is considered promising as a new agent for intratumoral injection therapy instead of ethanol.

Analysis of Variance↗
PubMed2006

Influence of rubber dam isolation on human pulp responses after capping with calcium hydroxide and an adhesive system.

OBJECTIVE: The objective was to evaluate the influence of rubber dam isolation on the response of human pulps capped with calcium hydroxide and an adhesive system. METHODS AND MATERIALS: Direct pulp capping was performed in 40 caries-free human premolars scheduled for extraction as part of orthodontic treatment. The teeth were randomly divided into 8 groups (n = 5) according to the combination of treatment factors: capping agent (adhesive resin or calcium hydroxide), isolation (rubber dam or cotton pellets only), and period of evaluation (30 or 60 days). Class 2 cavities were prepared, and pulp exposures were created on the occlusal floor. After capping, all teeth were restored with Z-100 placed incrementally. After 30 or 60 days, patients were asked about their symptoms, teeth were extracted, and serial sections were evaluated. The data were subjected to a nonparametric test. RESULTS: Overall, the histologic features showed that the pulp response was worse for groups capped with adhesive. For adhesive-capped groups, the pulp response varied from pulp necrosis to acute inflammatory cell infiltrate, and most of the pulps capped without rubber dam isolation showed severe inflammatory cell infiltrate involving the coronal pulp with chronic abscesses. For the calcium hydroxide groups, all specimens showed dentin bridge formation, regardless of the type of isolation used. CONCLUSION: Calcium hydroxide should be used as the material of choice for pulp capping with or without rubber dam isolation. The use of adhesive systems in vital pulp capping is contraindicated, especially if rubber dam isolation is not implemented.

Adhesives↗
PubMed1991

Sorption of sodium hydroxide by type I collagen and bovine corneas.

There are no quantitative studies on the uptake of alkali into corneal tissues. To study this phenomenon, both type I collagen and bovine corneas were incubated in sodium hydroxide (NaOH) under varying conditions for periods up to 27.5 h. The sorption (absorption or adsorption) of the alkali to protein and tissue was measured as the quantity of NaOH no longer available for titration to neutrality with hydrochloric acid. Sorption was found to be dependent on the concentration of NaOH (0.01-1 N) but independent of the incubation temperature (4-35 degrees C). In whole cornea, sorption of 1 N NaOH began immediately and increased with time up to 6 h. After 6 h, sorption decreased, together with the observed degradation and solubilization of the tissue. Stripping of the corneal endothelium alone or of the endothelium and epithelium increased sorption in a similar manner when compared to whole corneas for periods up to 4 h. These observations are compatible with ionic and nonionic bonding of hydroxide ions to collagen (including that of the cornea) and the subsequent release of hydroxide ions during hydrolysis of the protein itself. Indirect evidence also suggests the inclusion of quantities of unbound hydroxide ions in hydrated gels of glycosaminoglycans. It is proposed that in a chemical burn of the cornea, alkali is both stored in the tissue (by sorption) and reacted with it (by hydrolysis), without any net consumption of alkali taking place.

Absorption↗
PubMed1988

Aluminium hydroxide prevents progression in experimental focal glomerular sclerosis.

To investigate the effect of phosphate binding on the progress of chronic renal disease, aluminium hydroxide was administered to rats with focal glomerular sclerosis experimentally induced by adriamycin over a period of 28 weeks (group ADR-AH). The clinical data were examined every 4 weeks and the renal histology at week 28 were compared to those in adriamycin-injected rats without aluminium hydroxide treatment (group ADR). Urinary protein excretion was less marked in group ADR-AH than in group ADR at weeks 8 and 12. Serum creatinine in group ADR started to increase at week 20 and continued to rise until week 28, while in group ADR-AH it increased less, the difference being significant. Serum phosphate was lower in group ADR-AH than in group ADR at weeks 8, 12, 24, and 28. Focal glomerular sclerosis and tubulointerstitial changes were observed in both adriamycin-injected groups regardless of aluminium hydroxide treatment at week 28, although these changes were much less severe in group ADR-AH. There were no differences in body weight and serum albumin between the two groups. We conclude that aluminium hydroxide could prevent the renal deterioration in focal glomerular sclerosis induced by adriamycin without affecting the nutritional state.

Aluminum Hydroxide↗
PubMedDate not supplied

Resistance against Leishmania donovani induced with an aluminum hydroxide vaccine.

Mice immunized with a subcutaneous protocol combining killed parasites and aluminum hydroxide gel exhibited significant resistance against subsequent challenge with Leishmania donovani promastigotes. Protection was greatest using 25 mg of aluminum hydroxide per injection. Resistance elicited by this killed parasite and aluminum hydroxide protocol was as effective on day 14 as that provided by immunization with a glucan and killed parasite preparation, and more effective in hepatic amastigote reduction at day 28. The effectiveness of aluminum hydroxide as an adjuvant appears to result, at least in part, from its ability to activate macrophages, thus aiding in the elimination of this intracellular parasite.

Adjuvants, Immunologic↗
PubMed1988

Resonance Raman spectroscopic evidence for heme iron-hydroxide ligation in peroxidase alkaline forms.

Horseradish peroxidase will convert from a five-coordinate high-spin heme at neutral pH to a six-coordinate low-spin heme at alkaline pH. Though alkaline forms of other heme proteins such as hemoglobin and myoglobin are known to contain a heme-ligated hydroxide, alkaline horseradish peroxidase has been considered not to contain a ligated hydroxide. Several alternatives have been proposed which would be stronger field ligands than a hydroxide ion. In this report we provide resonance Raman evidence, using Soret excitation, that alkaline horseradish peroxidase does in fact contain a heme iron-ligated hydroxyl group. The band was located for isoenzymes C and A-1 by its sensitivity to 18O substitution and confirmed with 54Fe, 57Fe, and 2H. An isoenzyme of turnip peroxidase was investigated and found to also contain a ligated hydroxide at alkaline pH. The observed peroxidase Fe(III)-OH frequencies are 15-25 cm-1 higher than the corresponding frequencies of alkaline methemoglobin and metmyoglobin and correlate with changes in spin-state distribution. This is explained in the context of hydrogen bonding to a distal histidine which results in increased ligand field strength facilitating the formation of low-spin hemes. It has been demonstrated that the ferryl/ferric redox potential of horseradish peroxidase is markedly lowered at alkaline pH (Hayashi, Y., and Yamazaki, I. (1979) J. Biol. Chem. 254, 9101-9106). These observations are rationalized in terms of oxidation of a ligated ferric hydroxyl group facilitated through base catalysis by a distal histidine.

Heme↗
PubMed1987

[Antacid action of the aluminum cation: comparison of the in vitro effect of hydroxide and phosphate in open and closed systems].

Antacid capacity of two aluminium containing-antacid drugs was evaluated in vitro; the first drug contained aluminium hydroxide (Alternagel), the second, aluminium phosphate (Phosphalugel). The antacid evaluation was performed 1) in a closed system by measuring antacid activity by down titration, 2) by a dynamic evaluation simulating acid secretion and gastric emptying. The results were reported both to the recommended therapeutical dose and to 100 mg aluminium. In static conditions, without gastric emptying, it was shown that aluminium hydroxide and phosphate acted by their buffer capacity in pH range less than or equal to pH 1.5. The therapeutical dose of aluminium phosphate displayed greater antacid activity than aluminium hydroxide, this fact being due to the empiric choice of the doses. With regard to aluminium content, aluminium phosphate activity remained greater than that of aluminium hydroxide although the difference decreased with decreasing pH values. The antacid capacities were related to the emptying outputs. Antacid activity corresponding to 100 mg aluminium was similar in both antacids less than pH 1.5. This effect was dependent on emptying rates. It can be suggested that Al was responsible for antacid activity in both preparations, and that the buffering capacity was supported by the change of aluminium cation in hydrolysis intermediary compounds.

Aluminum↗
PubMed1978

Aluminum hydroxide: evaluation of two dosage forms and two dosing schedules in reducing intestinal phosphate absorption.

A crossover, randomized, eight-week trial using eight adult volunteers was undertaken to (1) determine the efficacy of aluminum hydroxide in decreasing gastrointestinal phosphate absorption, (2) compare the effectiveness of "with meal" and "between meal" dosing schedules, and (3) compare the effectiveness of the capsule and liquid dosage forms. Four treatments, each with a daily dose of approximately 6 g, were taken on a three-times-a-day regimen. The effectiveness of the treatment regimens was measured by using two variables: the decrease in total urinary phosphorus excretion, and the increase in the percent tubular reabsorption of phosphorus (TRP). Aluminum hydroxide treatment produced a significant change in urinary phosphorus excretion (p less than 0.0005) and in percent TRP (p less than 0.0005). For the study population, total urinary phosphorus excretion was the determining factor in changing the percent TRP. The increase in TRP and the decrease in total urinary phosphorus excretion was of the same degree regardless of dosage form or dosage schedule. Aluminum hydroxide was effective in decreasing phosphorus absorption as measured in this study. It appears that aluminum hydroxide capsules could be used with equal efficacy as the liquid dosage form in controlling hyperphosphatemia in patients with chronic renal failure who will not comply with a treatment program using the liquid.

Adult↗