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PubMed2001

The effect of experimental pleurodesis caused by aluminum hydroxide on lung and chest wall mechanics.

The aim of this study was to evaluate the effect of a chemical sclerosing agent, aluminum hydroxide, on pleural remodeling and on respiratory mechanics in rats. Saline (2 mL) or aluminum hydroxide [2 mL (0.15 g/mL)] was instilled intrapleurally in anesthetized male rats. The animals were studied 7 or 30 days after the instillation. Respiratory system, lung, and chest wall elastic, resistive, and viscoelastic/inhomogeneous pressures were measured by the end-inflation occlusion method. We studied the pleural remodeling process by means of semiquantitative analysis of the induced inflammation and quantitative analysis of the collagen extracellular matrix component. The effects on the underlying lung were analyzed morphometrically. Chest wall elastic and viscoelastic pressures increased after aluminum hydroxide instillation independent of time after instillation. Pleural inflammation was observed 7 days after instillation, while pleural adherence with a marked increase in the type I/type III collagen ratio was present 30 days after instillation. Histological examination demonstrated no differences in lung parenchyma among the groups. In conclusion, the present model describes the establishment of pleurodesis by aluminum hydroxide, which thwarts the normal chest wall mechanical profile without inducing any changes in the underlying lungs. The results were disclosed by both mechanical and morphological evaluation of the pleural remodeling.

Aluminum Hydroxide↗
PubMed2003

Comparison of the sodium dodecyl sulfate-sodium hydroxide specimen processing method with the C18-carboxypropylbetaine specimen processing method using the MB/BacT liquid culture system.

The ability of physicians to diagnose tuberculosis is impacted by the use of smear and culture techniques combined with specimen processing methods. The objective of this study was to evaluate the effects of specimen processing on smear and culture sensitivity by comparing the specimen processing method that uses C(18)-carboxypropylbetaine with the method that combines sodium dodecyl sulfate and sodium hydroxide. A total of 1,201 specimens were entered into this study. Specimens were split approximately equally such that one-half of each specimen was processed with sodium dodecyl sulfate-sodium hydroxide, while the other half was processed with C(18)-carboxypropylbetaine. All sediments were subjected to acid-fast staining and then analyzed using the MB/BacT liquid culture system (bioMérieux, France) and solid media. The sensitivity of smear following processing with sodium dodecyl sulfate-sodium hydroxide and C(18)-carboxypropylbetaine was 61.2% and 58.6% (P>0.05), respectively, while the specificities were identical (99.7%). The sensitivity of culture was 84.2% and 96.1% (P<0.05), respectively. The time to detection in the MB/BacT liquid culture system was 13.2+/-5.6 and 15.0+/-8.8 days (P>0.05), respectively, and 20.0+/-7.6 and 15.7+/-8.9 days (P<0.05), respectively, on solid media. The contamination rates in the MB/BacT system were 0.8% and 8.7%, respectively, whereas the contamination rates on solid media were 2.6% and 4.3%, respectively. C(18)-carboxypropylbetaine specimen processing was less labor-intensive than sodium dodecyl sulfate-sodium hydroxide processing and improved the ability of laboratory staff to detect the presence of mycobacteria by culture.

Bacteriological Techniques↗
PubMed1980

Effect of calcium hydroxide in powder or in paste form on pulp-capping procedures: histopathologic and radiographic analysis in dog's pulp.

The pulps of seventy dog teeth were evaluated histopathologically and radiographically following intentional exposure and treatment with either a calcium hydroxide powder or a calcium hydroxide paste prepared with distilled water. The results were recorded after periods of 2, 30, 70, and 120 days. No differences were detected in the pulpal responses to direct pulp capping achieved with a calcium hydroxide paste and with a calcium hydroxide powder.

Animals↗
PubMed1988

Calcium hydroxide and apexogenesis.

This case report describes the effect of calcium hydroxide in the treatment of traumatized immature tooth. Calcium hydroxide is used to fill the root canal after complete chemomechanical debridement has been performed. The result demonstrated the successful use of calcium hydroxide in stimulating the epithelial cells of Hertwig's sheath and the surrounding undifferentiated progenitor cells to continue formation of the apical portion of the root. Thus, the use of calcium hydroxide stimulated apical bridge formation, as well as inducing apexogenesis.

Calcium Hydroxide↗
PubMed1992

Effect of magnesium hydroxide on methylazoxymethanol acetate-induced epithelial proliferation in the large bowels of rats.

The effect of magnesium hydroxide on the epithelial proliferation of the large bowel was examined using rats given methylazoxymethanol (MAM) acetate. Dietary administration of magnesium hydroxide at 250, 500, 1000 or 2000 ppm. for 1, 3 or 5 weeks did not influence the cell cycle of the cryptal cells of the large bowel. However, the exposure to magnesium hydroxide under these conditions lowered the bromodeoxyuridine labeling index of the cells of the large bowel of the rats which had been initiated by MAM acetate (25 mg/kg, 3 times). The decrease in labeling index was more apparent in the proximal segment than in the distal segment. Such an inhibitory effect on the DNA synthesis of the epithelial cells by magnesium hydroxide may be related to the suppressive action of the trace element on the carcinogen-induced large bowel carcinogenesis.

Animals↗
PubMed2005

Comparison of the rabbit pyrogen test and Limulus amoebocyte lysate (LAL) assay for endotoxin in hepatitis B vaccines and the effect of aluminum hydroxide.

The rabbit pyrogen test and Limulus amoebocyte lysate (LAL) assay have been used to detect endotoxins in vaccines, but interactions between the endotoxins and proteins or aluminum hydroxide can interfere with the results. Currently, the rabbit pyrogen test is used to detect endotoxin in hepatitis B (HB) vaccines even though the HB surface protein, the active ingredient, is over-expressed in and purified from eukaryotic cells which lack endotoxin. Therefore, we examined the possibility of replacing the animal tests with the more efficient LAL test. To this end, we determined whether the aluminum hydroxide in the HB vaccines affects the rabbit pyrogen test and the LAL assay. HB vaccines and HB protein solutions spiked with lipopolysaccharide (LPS) produced almost the same dose-dependent temperature rise in rabbits, indicating that the aluminum hydroxide in the HB vaccine does not interfere with the pyrogenic response in rabbit. In contrast, a spike recovery study showed that aluminum hydroxide interfered with the LAL clot and kinetic assays; however, the LAL clot assay was effective at detecting endotoxin without loss of LAL activity after serial dilution of the samples. Furthermore, there was good correlation in the LAL clot assay between the amount of LPS added and the amount recovered. However, both turbidimetric and chromogenic kinetic assays displayed no correlation between the LPS amount added and recovered. Our results suggest that the LAL clot assay is sensitive and reliable when samples are properly prepared, and can be used to replace the rabbit pyrogen test for the detection of endotoxin in HB vaccines.

Aluminum Hydroxide↗
PubMed2006

Combining kinetic investigation with surface spectroscopic examination to study the role of aromatic carboxyl groups in NOM adsorption by aluminum hydroxide.

The adsorption of a series of aromatic carboxylic acids, with different numbers and positions of carboxyl groups in the phenyl ring, on aluminum hydroxide was investigated with ATR-FTIR and kinetic analyses to verify the role of aromatic carboxyl groups in the surface complexation of NOM with aluminum hydroxide. It was revealed that the formation of outer-sphere complexes dominated the adsorption of most of the aromatic carboxylates over the pH range examined in this study. Inner-sphere complexes were only detected at some pH levels for some aromatic carboxylates adsorption. The aromatic carboxylates were most likely to be adsorbed onto the first surface layer of hydroxyl groups and water molecules without forming coordinative bonds with the aluminum hydroxide surfaces, but strong hydrogen bonds were formed in this process. The adsorption data fitted the pseudo-second-order kinetic model very well. The activation energies of adsorption calculated from the rate constants of pseudo-second-order kinetics agreed with the ATR-FTIR analysis that the aromatic carboxylates, except pyromellitate, were adsorbed predominantly as outer-sphere complexes on aluminum hydroxide at pH 7. This study revealed that phenolic groups may be more significant than carboxylic groups for the chemical adsorption of NOM onto minerals. The presence of additional carboxylic groups enhanced the adsorption considerably, while the enhancement was limited when there were three or four carboxylic groups on the phenyl ring. The adsorption of aromatic carboxylates was affected by the positions and pK(a) values of the donor groups and the solution pH.

Adsorption↗
PubMed2004

Evaluation of disinfected casts poured in gypsum with gum arabic and calcium hydroxide additives.

STATEMENT OF PROBLEM: Disinfection of stone casts is an important measure for the control of cross-contamination. Many approaches have been used to disinfect stone casts, but information regarding the accuracy of the resultant casts is limited. PURPOSE: The purpose of this in vitro study was to evaluate the dimensional accuracy, incidence of abutment fracture, and the abutment reproduction of disinfected stone casts made from elastomeric impressions and to determine the effect of gum arabic and calcium hydroxide additives on these properties. MATERIAL AND METHODS: Two aqueous solutions of chemical disinfectants (0.525% sodium hypochlorite and 0.1% povidone iodine) were used as mixing water substitutes for 3 types of dental stone: Types III (Lab Stone), IV (Mile Stone), and V (Die Keen). These stone powders were subjected to further modification by adding 1% gum arabic and 0.132% calcium hydroxide before mixing at the manufacturer-recommended liquid/powder ratios (0.30 for Type III, 0.21 for Types IV and V, respectively). As these additives increased the fluidity of the mix, reduced liquid/powder ratios (0.26 for Type III, 0.19 for Types IV and V, respectively) were also evaluated. Unmodified stone powder mixed with water served as the control. These modifications resulted in 7 test groups for each type of stone. Mixed stones of these groups were poured into 10 putty/wash vinyl polysiloxane impressions made of a customized definitive cast. The percentage of abutments fractured at the time of releasing the resultant casts, as well as the percentages of incompletely reproduced abutments, abutments with air bubbles, and abutments with defective finish lines were compared statistically among the tested groups using the chi-square test (alpha=.05). The average dimensional deviations of the resultant cast from the definitive cast measured in mm were statistically analyzed using 1-way ANOVA (alpha=.05) followed by the Dunnett test to detect any differences among the tested groups. RESULTS: No significant difference was found in abutment fracture or abutment defects for the different formulations of each type of stone used. The resultant casts showed no significant dimensional changes except for Type III and IV stones modified by gum arabic and calcium hydroxide additives and mixed at the recommended liquid/powder ratios. CONCLUSION: Both 0.525% sodium hypochlorite and 0.1% povidone iodine can be used to disinfect dental gypsum with no significant effect on the dimensional accuracy and reproducibility of the resultant casts. Addition of gum arabic and calcium hydroxide to the hemihydrate powders before mixing does not aid in reducing the incidence of defective abutment reproduction.

Analysis of Variance↗
PubMed2005

Investigation of pH at different dentinal sites after placement of calcium hydroxide dressing by two methods.

OBJECTIVE: The dentin pH at different sites following placement of calcium hydroxide paste using 2 different methods was evaluated. STUDY DESIGN: One hundred twenty Extracted teeth were instrumented and randomly divided into 6 different groups. Then they were dressed with calcium hydroxide by 2 different methods using paper points or Lentulo spiral, according to their respective groups, and stored. After the experimental period of time, half of the samples were cut transversally into slices and the other half split longitudinally and rinsed with distilled water. The dentin pH of cervical, middle, and apical thirds was measured from the root canal wall surface and 1 mm away from the root canal lumen in the inner dentin. The results were compared and statistically analyzed. RESULTS: The highest pH values were obtained on the root canal walls when the calcium hydroxide was placed with Lentulo spiral filler (P > .05). There was a significant reduction in pH values in the inner dentin. When the cross sections of teeth were compared at 7 days, the Lentulo group was statistically different only in the apical third. CONCLUSIONS: Placement of the calcium hydroxide paste with a Lentulo spiral with subsequent compaction with the blunt end of a sterile paper point obtained a higher pH value on the canal walls and in the inner dentin than paper points only.

Analysis of Variance↗
PubMed2006

In vitro assessment of the effectiveness of chlorhexidine gel and calcium hydroxide paste with chlorhexidine against Enterococcus faecalis and Candida albicans.

OBJECTIVE: The purpose of this study was to compare the effectiveness of various medicaments, including Ca(OH)2/2% chlorhexidine, 2% chlorhexidine gel, and Ca(OH)2 alone, against Enterococcus faecalis and Candid albicans in vitro. STUDY DESIGN: Eighty extracted single-rooted human maxillary teeth were used. After removing the crown, each root was instrumented up to size 50 by using a conventional technique. The root canal was irrigated with ethylenediamine tetra-acetic acid (EDTA) solution to remove smear layer. Then, roots were infected with E faecalis and C albicans. Subsequently, the roots were divided into 4 treatment groups: group 1 was treated with calcium powder hydroxide in distilled water, group 2 was treated with calcium hydroxide powder in 2% chlorhexidine, group 3 was treated with 2% chlorhexidine gel, and group 4 was treated with 0.9% sterile saline serving as negative control. Microbial samples were taken after 7, 15, and 30 days. After incubation, dentine chips were obtained form each root canal and examined microbiologically. The microbiological samples were plated to count colony-forming units in per milligram of dentin. RESULTS: The results showed that the 2% chlorhexidine gel was significantly more effective than calcium hydroxide with 2% chlorhexidine, calcium hydroxide, and control saline solution (P < .05). CONCLUSION: Under the conditions of this study, 2% chlorhexidine gel is effective in the elimination of E faecalis and C albicans from the root canal system. However, to support this in vitro observation, further in vivo studies are needed.

Anti-Infective Agents, Local↗
PubMed2006

Effect of a calcium hydroxide-based root canal dressing on periapical repair in dogs: a histological study.

OBJECTIVE: To compare the periapical repair of teeth with periapical lesion following root canal treatment by using a calcium hydroxide-based intracanal dressing for several time periods or filling in a single visit. STUDY DESIGN: After induction of periapical lesions in 4 dogs, the root canals were prepared using 5.25% sodium hypochlorite for irrigation, and animals were separated into 4 experimental groups; in group I, root canals were filled in a single session; in groups II, III, and IV, a calcium hydroxide-based dressing was kept in place for 15, 30, or 180 days, respectively. Root canals from groups I, II, and III were filled with gutta-percha cones and AH Plus sealer. After 180 days, animals were killed and histological sections were stained with hematoxylin-eosin to evaluate periapical repair. RESULTS: Periapical repair was better in groups II, III, and IV (intracanal dressing) compared with group I (single session; P < .05). CONCLUSION: The use of a calcium hydroxide-based intracanal dressing was important for periapical repair in teeth with periapical lesion. Dressing with calcium hydroxide paste results in better periapical repair than when the root canal is filled in a single-session treatment.

Animals↗
PubMed2006

Sewage sludge stabilisation with calcium hydroxide: effect on physicochemical properties and molecular composition.

Raw primary sewage sludge (Wastewater Treatment Plant of Krotoszyn, SW Poland) and its mixtures with 3%d, 6%d, 9%d, 12%d and 24%d of calcium hydroxide were stabilised for 1 and 35 days. Changes of the sludge physicochemical properties and molecular composition, caused by alkaline agent in course of stabilisation process, are recognised. A basic physicochemical data on the sludge cake and filtrate after 1 and 35 days of stabilisation process are given. Soxhlet extracts from the sludge cakes stabilised for 35 days as well pyrolysis and pyrolysis in situ methylation (using tetramethylammonium hydroxide-TMAH) products of respective pre-extracted cake residues were analysed by gas chromatography-mass spectrometry (GC-MS). Increase of calcium hydroxide concentration in the sludge mixture causes enhanced ammonia release, preferential hydrolyses of fats and proteins from the sludge macromolecular network and transformation of free fatty acids contained in the sludge lipids, as well as these released hydrolytically, to their calcium salts. The sewage sludge stabilisation with calcium hydroxide has no effect on homological assemblage and content of unbound stanol and sterol compounds in the sludge lipids and these bound into macromolecular network. Biogenic n-alkanes and anthropogenic linear alkylbenzenes were detected as minor components in the lipids and pyrolytic products from the pre-extracted cake residue, respectively. The alkaline agent used for the sludge stabilisation accelerates equilibration of the process and reduces content of pathogenic microorganisms.

Ammonia↗
PubMed1988

Chlorthalidone reduces calcium oxalate calculous recurrence but magnesium hydroxide does not.

We examined the effectiveness of chlorthalidone or magnesium hydroxide in the prevention of recurrent calcium oxalate kidney calculi. In a double-blind random allocation design daily dosages of 25 or 50 mg. chlorthalidone, 650 or 1,300 mg. magnesium hydroxide, or an identical placebo were administered. All groups showed significantly decreased calculous events compared to the pretreatment rates. During the trial 56.1 per cent fewer calculi than predicted developed in the placebo group (p less than 0.01), whereas the groups receiving low and high dosage magnesium hydroxide showed 73.9 and 62.3 per cent fewer calculi, respectively (p less than 0.001 and less than 0.01, respectively). Chlorthalidone treatment resulted in a 90.1 per cent decrease from predicted rates and both dosages yielded similar results. When the treatments were compared chlorthalidone was significantly better than the placebo or magnesium hydroxide (p less than 0.01). The large decreases in calculous events seen when placebo or ineffective therapy was given underscore the positive treatment bias that occurs when historical controls are used and they demonstrate the need for proper experimental design.

Calcium Oxalate↗
PubMed2002

Removal of phosphate by layered double hydroxides containing iron.

Iron-based layered double hydroxides (M2+(a)Fe3+(b) (OH)2(a+b) CO3(2-) b/2mH2O) were synthesized. Removal of phosphate by the compounds was studied from the viewpoint of buffering pH effect of the compounds and buffering capacity of solution. The compounds released metal cations (Mg2+, Ca2 , Fe3+) and/or their hydroxides responding to various water environments due to their buffering pH function. The released cations and/or hydroxides worked effectively as coagulants for the phosphate removal. The removal of phosphate depended on the buffering capacity of the solution that is the function of the solution pH and the concentration of phosphate. The removal of phosphate from the solution with small buffering capacity followed a Langmuir-type isotherm. The removal of phosphate from the solution with larger buffering capacity was largely increased. The removal of phosphate by the compounds was analyzed based on the model describing the buffering pH effect of the compounds from which the amount of released cations (CB) can be determined. The removal was well correlated with the amount of dissolution of the compounds, CB. The mechanism of phosphate removal was examined based on the removal efficiency (mol of removed phosphate/mol of released alkali). The efficiencies showed below one in the solution with large buffering capacity and above one in the solution with small buffering capacity. The efficiency below one showed the removal of phosphate through coagulation by the released metal cations and hydroxides. The successful removal of dilute phosphate (0.2mg P/l) from the drain water was also demonstrated.

Cations↗
PubMed2003

Application of 'waste' metal hydroxide sludge for adsorption of azo reactive dyes.

The capacity and mechanism of metal hydroxide sludge in removing azo reactive dyes from aqueous solution was investigated with different parameters, such as charge amount of dyes, system pH, adsorbent particle size, and adsorbent dosage. The three anionic dyes used were CI Reactive Red 2, CI Reactive Red 120, and CI Reactive Red 141, increasing in number of sulfonic groups, respectively. Only 0.2% (w/v) of powdered sludge (<75microm) achieved color removal from 30 mg l(-1) reactive dye solutions within 5 min without pH adjustment. The larger the charge amount of the dyes, the greater the adsorption (>90%) on the metal hydroxide sludge. The system pH played a significant role in the adsorption on metal hydroxides and formation of dye-metal complexes. The optimum system pH for dye adsorption was 8-9 which was close to the pH(zpc) of the sludge while the precipitation of dye-metal complexes occurred at system pH 2. The maximum adsorption capacity (Q degrees ) of the sludge for the reactive dyes was 48-62 mg dye g(-1) adsorbent. The Langmuir and Freundlich models showed that the higher charged dyes had a higher affinity of adsorption. The smaller particle size and the greater amount of adsorbent showed the faster process, due to an increase in surface area of adsorbent. Desorption studies elucidated that metal hydroxide sludge had a tendency for ion exchange adsorption of sulfonated azo reactive dyes. Leaching data showed that the treated water was nontoxic at a system pH above 5 or a solution pH above 2.

Adsorption↗
PubMed2003

Dewatering of alumino-humic sludge: impacts of hydroxide.

The paper draws together information on factors which influence the conditioning and dewatering behaviour of an alum sludge gained from the coagulation of a low-turbidity coloured water. A principal focus is the potential impact of aluminium hydroxide on the sludge character. Background information is provided on the composition of the source floc for the domain pH 6.0-6.5 and Al>2.0mg/l. From this, there were many pointers to the presence of Al(OH)(3)(s) within the floc. A series of comparisons were made between an alum sludge and a hydroxide suspension at a concentration equivalent to the coagulant fraction within the sludge. The parameters studied included floc size, floc density, polymer adsorption and dewatering behaviour at different time-scales. In all cases, there were strong similarities in the behaviour of the two suspensions-indicating the potential impact of the hydroxide. There was also evidence of common features being displayed by both the organic fractions and the hydroxide. It was suggested that some of the behavioural features might emanate from a common fractal structure within the source floc, the fractal dimension (approximately 1) being insensitive to composition.

Alum Compounds↗
PubMed1989

Tubular permeability to calcium hydroxide and to bleaching agents.

Recent reports of clinical cases suggest that cervical root resorption may follow bleaching of endodontically treated teeth. Inflammatory root resorption may be arrested by placement of calcium hydroxide into the root canal. The dentinal tubules are assumed to be a possible route of action for both agents. pH Values of the medium surrounding the tooth after placement of bleaching agents and calcium hydroxide within the root canals were determined in this study. Thirty extracted single-rooted human teeth were divided into three equal groups. The pulp cavity of the experimental teeth was filled with either bleaching agents or calcium hydroxide. In the control group it was left empty. Dipping in paraffin sealed the access cavity and the apical foramina and isolated the teeth except at the cervical root surface. The teeth were placed in vials containing distilled water and the pH of the medium was measured after 1 h, 3 days, and 7 days following renewal of the medium. The level of the pH in the first group increased, indicating that the bleaching agents leaked from the root canal to the medium surrounding the teeth. The pH in other two groups did not change noticeably. The results suggest that bleaching agents may leak from the root canal toward the periodontal tissues but calcium hydroxide does not alkalinize the medium surrounding the teeth. Leakage of the bleaching agents through dentin may, therefore, be considered as a possible etiological factor that initiates an inflammatory process around the teeth that may be followed by cervical root resorption.

Calcium Hydroxide↗
PubMed1996

pH changes at the surface of root dentin when using root canal sealers containing calcium hydroxide.

The purpose of this study was to investigate long-term pH changes in cavities prepared in root surface dentin of extracted teeth after obturation of the root canal with gutta-percha and a variety of sealers containing calcium hydroxide. After cleaning and shaping, root canals in 50 recently extracted, human single-rooted teeth were divided into five groups. Each of four groups was obturated with gutta-percha and either Sealapex, Sealer 26, Apexit, or CRCS, all of which contain calcium hydroxide. The remaining group served as the control and was not obturated with gutta-percha or sealer. Cavities were prepared in the facial surface of the roots in the cervical and middle regions. The pH was measured in these dentinal cavities at the initiation of the experiment, and 3, 7, 14, 21, 28, 45, 60, 90, and 120 days after obturation. Results indicate that the pH at the surface of the root does not become alkaline when calcium hydroxide cements are used as root canal sealers. Regardless of the sealer used, the observed pattern of pH change was not different from that seen in the control group of roots that were not treated with sealer. It is concluded that calcium hydroxide-containing cements, although suitable for use as root canal sealants, do not produce an alkaline pH at the root surface. If such a pH change is related to treatment of root resorption, these sealants do not contribute to this treatment.

Bismuth↗