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PubMed2005

Effect of electrophoretically activated calcium hydroxide on bacterial viability in dentinal tubules--in vitro.

To evaluate the ability of electrophoretically activated calcium hydroxide (CH) to eliminate bacteria in dentinal tubules. In an in vitro model of dentinal tubule infection, 18 cylindrical root specimens prepared from freshly extracted bovine teeth were used. After removal of the smear layer, intracanal dentinal tubules were infected with Enterococcus faecalis for 21 days. In 12 specimens, CH paste was placed in the root canals for 7 days. In six of these, an electrophoretic current (10 mA per 10 min), using two electrodes, was applied after placing the medicament in the canal. Powder dentin samples obtained from within the canal lumina using ISO 025, 027, 029, 031 and 033 burs were examined for the presence of vital bacteria by inoculating agar plates and counting colony forming units. anova with repeated measures was used to analyze results. A significant difference was found between experimental groups and the positive control group. CH and electrophoretically activated CH significantly (P <0.001) reduced bacterial viabilities in dentinal tubules to a depth of 200 microm. Treatment with electrophoresis was significantly (P <0.001) more effective than pure CH in depths of 200-500 microm. Specimens treated with electrophoretically activated CH showed no viable bacteria in dentinal tubules to a depth of 500 microm from the root canal space within 7 days. The time required for treatment of pulpal infection root resorption may be decreased, thus minimizing the risk of coronal fractures in young patients with traumatized teeth.

Analysis of Variance↗

PubMed1994

Comparative effect of calcium hydroxide and hydroxyapatite on the cellular activity of human pulp fibroblasts in vitro.

When, in vivo, calcium hydroxide [Ca(OH)2] or hydroxyapatite are used as dental pulp-capping agents, a reparative dentine bridge is observed. New hard tissue is formed directly on the hydroxyapatite, whereas a characteristic necrotic area appears under Ca(OH)2. The differing pulpal reactions to these two capping agents suggest differing cell responses. After isolation and selection of human pulp fibroblasts in vitro, the cells were characterized by their morphology, their high alkaline phosphatase specific activity, and their synthesis of type I and III collagens and fibronectin. They were then incubated in the presence of either hydroxyapatite (1 mg/ml) or Ca(OH)2 (0.8 mg/ml). With Ca(OH)2, the cells exhibited dramatical alterations in morphology, DNA synthesis, alkaline phosphatase activity and protein synthesis, in accordance with the necrosis observed in vivo. With hydroxyapatite, phagocytic activity of pulpal fibroblasts toward hydroxyapatite particles (< 10 microns) was seen. As a consequence, DNA synthesis was affected. This inhibitory effect was not due to cell damage, as demonstrated by increased [3H]-proline and [3H]-leucine incorporation by the cells. There was also an inhibitory effect of hydroxyapatite on alkaline phosphatase activity, suggesting that the pulp fibroblasts were not in a differentiation stage. In conclusion, compared to the effects of Ca(OH)2 on human pulp fibroblasts, these data are consistent with the biocompatibility of hydroxyapatite previously described in vivo and testify to the occurrence of a biological response elicited by this synthetic biomaterial.

Adolescent↗

PubMed2003

Chemical and antimicrobial properties of calcium hydroxide mixed with irrigating solutions.

AIM: Chemical and antimicrobial effects of paste-like suspensions of calcium hydroxide (Ca(OH)2) powder with chlorhexidine (CHx), sodium hypochlorite (NaOCl) or iodine potassium iodide (IPI) solutions were tested and compared to conventional Ca(OH)2/saline paste. METHODOLOGY: Equivalent mixtures of Ca(OH)2 with irrigating solutions were compared to conventional Ca(OH)2/saline paste for their ability to raise the pH in root dentine. Ca(OH)2 pastes were compacted into prepared root canals of single-rooted extracted human teeth. Changes in root pH over time were recorded with a microelectrode placed in standardized wells within root surfaces. Antimicrobial efficacy of test solutions and pastes against Enterococcus faecalis and Candida albicans was assayed using an agar diffusion test. RESULTS: The ability of Ca(OH)2 to raise the pH in the root dentine was maintained when using mixtures of Ca(OH)2 with CHx, NaOCl or IPI (Kruskal-Wallis, P > 0.05). Mixtures of Ca(OH)2 with the test solutions had similar antimicrobial properties as equivalent mixtures with saline (anova, P > 0.05). The efficacy of CHx was reduced when mixed with Ca(OH)2. No additive antiseptic effects were recorded between Ca(OH)2 and IPI or Ca(OH)2 and NaOCl. CONCLUSIONS: Ca(OH)2 is a strong alkali, whose pH is not changed when adding weak acids or alkalis in aqueous suspensions. Under the conditions of this study, mixing Ca(OH)2 powder with the test irrigating solutions did not provide an increased antimicrobial effect compared to a conventional Ca(OH)2/saline medication.

Analysis of Variance↗

PubMed1980

Apical hard-tissue deposition in adult teeth of monkeys with use of calcium hydroxide.

The periapical tissues of adult teeth of monkeys were examined histologically after root canal treatment with calcium hydroxide. Healing, as evidenced by complete apical closure with a hard tissue bridge and an inflammation-free periodontal ligament, occurred more frequently where canals were instrumented 1 mm short of the apex. Overinstrumented canals exhibited a significantly decreased incidence of apical closure.

Animals↗

PubMed1990

[Root canal obturation based on Sealapex calcium hydroxide. A clinical and radiological follow-up after 1 year].

To assess the efficiency of a calcium hydroxide containing root canal sealer (Sealapex), 227 obturated canals were examined clinically and radiologically after one year. When compared to a previously published study (Verdon & Holz 1988), the results show a decline of radiopacity within the canals and an almost complete resorption of the cement overfillings. It was also noted a slight improvement in the radiologic appearance of the periapical lesions.

Calcium Hydroxide↗

PubMed1987

[Treatment of wheat straw with urea, calcium hydroxide or ammonium sulfate].

An experiment was conducted to evaluate the effectiveness of urea, ammonia sulphate or calcium hydroxide, in improving the nutritive value of wheat straw for ruminant feeding. Wheat straw was treated with each of three solutions (w/w) containing: 5% urea - 50% H2O (5U); 2% urea - 2% CaOH - 50% H2O (2U), or 5% ammonia sulphate - 2% CaOH - 50% H2O (5S). The treated straw was then ensiled in triplicate in sealed polyethylene bags for 30 days at ambient temperature (15-22 degrees C), except for the untreated straw, which was used as control (T). All treatments were then subjected to the following determinations: pH, moisture, crude protein, ammonia N, ashes, cellular walls, hemicellulose, cellulose, lignin, silica, gross energy, and dry matter in vitro digestibility. The pH value of the 5U treatment was higher (p less than 0.01) than that of 2U and 5S, and the moisture percentage increased in all treated straws, as compared to the control. Both crude protein and ammonia N contents were higher in the 5U treated straws (14.66; 0.6%), 2U (6.41; 75%), 5S (9.54; 94%) in comparison with T (2.63; 50%). The ash percentage increased significantly in 2U and 5S (p less than 0.01) in relation to T and 5U, and the cellular wall content decreased in the 5U, 2U and 5S treated straws, as did cellulose. Gross energy values were higher in the treated straws, and the dry matter per cent digestibility was also higher, although not in a significant degree (p less then 0.01) in the 5% urea-treated straw (45.03) than in 2U (42.43), 5S (34.82), and T (42.36).(ABSTRACT TRUNCATED AT 250 WORDS)

Ammonium Sulfate↗

PubMed1997

Chemical analysis of the formation of calcium carbonate and its influence on calcium hydroxide pastes in connective tissue of the dog--Part II.

The objective of this research was to chemically analyze calcium hydroxide pastes added to three hydrosoluble vehicles having different acid-base characteristics by implanting polyethylene tubes in subcutaneous connective tissue in dogs, evaluating the formation of calcium carbonate over a period of 7, 30, 45, and 60 days. The three vehicles were saline, anesthetic, and polyethylene glycol 400. Determination of the formation of calcium carbonate was evaluated by volumetry of neutralization using hydrochloric acid for titration.

Animals↗

PubMed1983

The antibacterial effects of calcium hydroxide apexification pastes on Streptococcus sanguis.

Four calcium hydroxide-based apexification pastes were tested for their antibacterial effects on Streptococcus sanguis. Their zones of growth inhibition on blood agar plates were measured at 2, 4, 6, and 8 days. Only the camphorated parachlorophenol and the metacresylacetate pastes showed zones of inhibition. Both of these zones of inhibition decreased with time; however, the zones of inhibition for the parachlorophenol paste decreased at a slower rate.

Calcium Hydroxide↗

PubMed2006

[Diffusion of hydroxyl ions from calcium hydroxide in the dentinal tubules].

The aim of this study was to compare hydroxyl ions diffusion from various calcium hydroxide forms: Hycal (1), Roeko points (2) and aqueous suspension placed in the pulpar chamber (3) or in the root canal (4). These experiments were conducted with bovine incisors in order to obtain quantitative evaluation. 540 lateral cavities, deep and superficial, were created in root dentin to measure the hydroxyl ions diffusion with a color indicator, the Blue epsilon With Hycal and aqueous suspension the diffusion of the OH- is obtained in the superficial cavities situated in the coronal part at 14 days (1 = 72%; 3 = 44%; 4 = 100%, (n=18)). In the apical part of the canal this phenomenon is never complete at 21 days (1 = 17%; 3 = 22%; 4 = 17%, (n=18)). No diffusion was observed with the Roeko points (the first generation).

Animals↗

PubMed2003

In vitro diffusion of hydroxyl ions through root dentine from various calcium hydroxide medicaments.

The purpose of this study was to determine diffusion of hydroxyl ions through dentine from different calcium hydroxide [Ca(OH)2] medicaments. Forty-five single-rooted teeth were instrumented and cavities (3 mm in diameter and 1 mm in depth) were prepared on the facial surface of each root. After smear layer was removed with 17% EDTA all surfaces of roots, except cavities, were coated with nail polish. Teeth were randomly divided into four experimental groups (each 10 samples) and a control group (five samples). They were filled with: group 1, Ca(OH)2 and distilled water mixture; group 2, TempCanal; group 3, Calasept; and group 4, Ca(OH)2 plus point. Control group, in which nothing was applied to the canals. All samples were immersed in distilled water maintained at 37 degrees C. pH values were measured at 1 h, 2 h, 3 h, 24 h, 48 h, 72 h, 4 days, 5 days, 6 days, 7 days and 14 days. Ca(OH)2-distilled water mixture and TempCanal showed highest pH values at 24 h. Calasept, Ca(OH)2 plus point and control showed highest pH values at 3 h. Time intervals after 24 h, Ca(OH)2-distilled water mixture, TempCanal and Calasept showed higher pH values than Ca(OH)2 plus point, with a statistically significant difference (P<0.05). The pH value of Ca(OH)2 plus point was lower than the values of other materials after 3 h. This study indicates that non-setting Ca(OH)2 based materials have an effective release of hydroxyl ions compared with Ca(OH)2 plus point.

Calcium Chloride↗

PubMed2006

Clinical and microbiological effect of calcium hydroxide protection in indirect pulp capping in primary teeth.

PURPOSE: To evaluate clinically and microbiologically the effect of calcium hydroxide (CH) on carious dentin on primary teeth submitted to indirect pulp capping (IPC). METHODS: Twenty 4-7 year-old subjects with 42 treated teeth participated in the study. The treatment consisted of incomplete excavation of the demineralized dentin, application of a CH or gutta-percha (GP) layer and sealing with a resin-based composite for 4-7 months. After cavity preparation and sealing, the dentin was evaluated clinically (color and consistency) and microbiologically. Dentin samples were cultured on blood agar under aerobic and anaerobic conditions, in Mitis Salivarius agar and Rogosa SL agar. RESULTS: 39 teeth (20 in the CH Group and 19 in the GP Group) were reopened 4-7 months post-treatment for clinical and microbiological evaluation. In all teeth, the initial demineralized dentin was wet and soft or leathery. In the CH Group, 10% of the lesions were yellow, 80% light brown and 10% dark brown and in the GP Group, 94.7% were light brown and 5.3% dark brown. After treatment, the dentin was dry, 90% (Group CH) and 84.2% (Group GP) were dark brown. The final consistency was either leathery or hard. Three samples in the CH Group and five in Group GP changed from soft to leathery; only one sample (GP) remained leathery. 85% in the CH Group and 68.4% in GP Group turned hard after treatment. All bacterial counts decreased significantly by the end of treatment. In the CH Group, the bacterial (Log10 CFU + 1) anaerobic growth decreased from 4.84 +/- 1.31 to 1.35 +/- 1.54, aerobic from 4.09 +/- 1.04 to 0.92 +/- 1.30 and lactobacilli from 3.24 +/- 1.22 to 0.36 +/- 0.89, respectively; the mutans streptococci from 2.05 +/- 1.84 to 0.14 +/- 0.60. In GP Group, anaerobic growth decreased from 5.22 +/- 0.96 to 2.02 +/- 1.65 and aerobic from 4.23 +/- 1.37 to 1.08 +/- 1.29 and lactobacilli from 2.06 +/- 1.81 to 0.00 +/- 0.00, respectively; the mutans streptococci from 3.16 +/- 1.59 to 0.28 +/- 0.84.

Calcium Hydroxide↗

PubMed1989

Pulpal tissue changes following pulpotomies with formocresol, glutaraldehyde-calcium hydroxide, glutaraldehyde-zinc oxide eugenol pastes in primary teeth.

Pulpal tissue changes following pulpotomies with formocresol, glutaraldehyde-calcium hydroxide and glutaraldehyde-zinc oxide eugenol pastes in primary teeth were investigated for a period of 12 months. Compared with the other groups, clinical, radiographic and histologic examinations revealed glutaraldehyde-zinc oxide eugenol combination had a higher success rate.

Aldehydes↗

PubMed1999

Reaction of rat connective tissue to implanted dentin tubes filled with mineral trioxide aggregate or calcium hydroxide.

This study was conducted to observe the rat subcutaneous connective tissue reaction to the implanted dentin tubes filled with calcium hydroxide or mineral trioxide aggregate. The animals were sacrificed after 7 and 30 days, and the specimens were prepared for morphological study. Some undecalcified specimens were prepared for histological analysis with polarized light and Von Kossa technique for calcium. The results were similar for both studied materials. At the tube openings, there were Von Kossa-positive granules that were birefringent to polarized light. Next to these granulations, there was an irregular tissue like a bridge that was Von Kossa-positive. The dentin walls of the tubes exhibited in the tubules a structure highly birefringent to polarized light, usually like a layer and at different depths. It is possible that the mechanism of action of both materials has some similarity.

Aluminum Compounds↗

PubMed2006

Vehicle influence on calcium hydroxide pastes diffusion in human and bovine teeth.

The purpose of this study was to compare the pH and calcium ion liberation after use of calcium hydroxide pastes with different paste vehicles in human or bovine teeth. Ninety-two single-rooted human and bovine roots were used. The roots were instrumented and an external cavity preparation was performed. The roots were divided in to human and bovine groups. Each group was subdivided into four subgroups (SB) according to the vehicle:SB1, detergent; SB2, saline; SB3, polyethylenoglycol + camphorated paramonochlorophenol (Calen PMCC) and SB4, polyethylenoglycol + furacyn paramonochlorophenol (FPMC). Specimens were immersed into saline solution at 37 degrees C and after 7 and 14 days pH and calcium ion measurements were made. The results were analyzed by anova and Tukey tests (P < 0.05). There was no statistical difference between bovine and human teeth in the pH analysis (P < 0.05), but bovine teeth provided larger calcium ion liberation than human teeth. Calen PMCC was statistically more effective for pH increase and calcium ion liberation in all analyses, followed by FPMC and saline. Detergent showed the lowest pH alterations and calcium ion liberation. The period of 14 days showed more calcium ionic liberation than the 7-day period.

Analysis of Variance↗

PubMed2005

Antimicrobial efficacy of chlorhexidine and two calcium hydroxide formulations against Enterococcus faecalis.

The purpose of this study was to investigate the efficacy of chlorhexidine (CHX) and calcium hydroxide (Ca(OH2) against Enterococcus faecalis in vitro. Extracted single-rooted human teeth were instrumented up to size 40. After removal of the smear layer, an inoculum of E. faecalis was inserted into the root canals. After incubation, the inoculum was removed and the root canals were filled with one of three different disinfectants: Ca(OH2 paste, CHX 2%, and a mixture of CHX and Ca(OH2 paste (n = 10 in each group). Control teeth were filled with water of standardized hardness (n = 10). The teeth were then incubated for 3 days. After incubation, each root canal was instrumented, and the removed dentin was examined microbiologically. CHX was significantly more effective against E. faecalis than was Ca(OH2 paste or a mixture of CHX with Ca(OH2 paste (p < 0.05). There was no increase in the efficiency of Ca(OH2 paste when CHX was added (p > 0.05). The results suggest that CHX is effective in the elimination of E. faecalis from dentinal tubules under the conditions of this study.

Calcium Hydroxide↗

PubMed2000

TGF-beta 1 alone and in combination with calcium hydroxide is synergistic to TGF-beta 1 production by osteoblasts in vitro.

AIM: To examine the effects of calcium hydroxide (Ca(OH)2), transforming growth factor-beta (TGF-beta 1), and Ca(OH)2/TGF-beta 1 coadministration on TGF-beta 1 and interleukin-6 (IL-6) synthesis by early (subculture 1) and late (subculture 5) osteoblast cultures. METHODOLOGY: Early and late cultures were established using bone cells harvested from 21-day-old fetal rat calvaria. Cell cultures of both early and late osteoblasts were divided into four groups: group 1, control; group 2, cells challenged with Ca(OH)2; group 3, cells challenged with TGF-beta 1; and group 4, cells challenged with Ca(OH)2 and TGF-beta 1 in combination. TGF-beta 1 and IL-6 levels for all groups were determined using ELISA methodology. RESULTS: ANOVA and Tukey HS analyses revealed that osteoblasts of groups 3 and 4 significantly increased (P < 0.001) TGF-beta 1 synthesis in both early and late cultures of osteoblasts. IL-6 was not detected in any of the groups considered in this study. CONCLUSIONS: Exogenous TGF-beta 1 has an autocrine effect on cell cultures of osteoblasts. Administration of TGF-beta 1 alone or in combination with Ca(OH)2 increases the synthesis of TGF-beta 1 in osteoblast cultures. Ca(OH)2 and TGF-beta 1 are compatible when placed in a culture of osteoblasts. Ca(OH)2 provides a favourable environment for the anabolic effects of TGF-beta 1.

Analysis of Variance↗

PubMed2001

Antimicrobial activity of several calcium hydroxide preparations in root canal dentin.

The purpose of this study was to evaluate the antimicrobial activity of several calcium hydroxide (Ca(OH)2) preparations in root canal dentin infected with Enterococcus faecalis. Roots of extracted bovine incisors were prepared to standardized cylindrical test specimens of 5 mm in height; the smear layer was removed, and the specimens were incubated for 24 h at 37 degrees C in bacteriological culture medium that contained 7.0 x 10(4) colony forming units per milliliter of E. faecalis. The specimens were mounted in individual 4-mm diameter culture wells, and the test material was applied to fill the canal lumen. There were five treatment groups: group 1, a thick mixture of Ca(OH)2 USP (1.0 g/ml H2O); group 2, a thin mixture of Ca(OH)2 USP (0.1 g/ml H2O); group 3, Pulpdent TempCanal paste; group 4, sterile H2O (positive control); and group 5, 25 dentin specimens in sterile, uninoculated brain-heart infusion broth that were included as negative controls. Quantitative microbiological analysis of dentin at various depths was completed after 24 h. All groups showed a significant (p < 0.001) decrease in numbers of E. faecalis in all depths of dentin compared with the control. Groups 2 and 3 demonstrated significantly greater antimicrobial activity (73%-86% reduction) at all depths of dentin tested compared with group 1 (13%-26%) (p < 0.05). These results suggest that Ca(OH)2 can decrease the numbers of E. faecalis at all depths of dentinal tubules within 24 h and that thin preparations of Ca(OH)2 may be more effective in the elimination of E. faecalis from dentinal tubules than thick preparations.

Analysis of Variance↗

PubMed2006

Comparison of fracture resistance in root canals of immature sheep teeth after filling with calcium hydroxide or MTA.

Thirty immature sheep incisor teeth were tested for their fracture resistance after various treatment modalities using calcium hydroxide (CH) or a mineral trioxide aggregate material (MTA) as a root filling. The incisors, having approximately 80% of their root growth completed, were removed from jaws of slaughtered sheep and divided into four experimental groups. The pulps were extirpated from all the teeth through the open apexes. (a) Saline group: the teeth were preserved in saline for 100 days at 6 degrees C. (b) CH group: the root canals were filled with CH and sealed apically with IRM and stored as above. (c) MTA group: the canals were filled with MTA and stored as above. (d) CH+MTA group: the canals were filled with CH and sealed with IRM. After 30 days, the CH was replaced with MTA and stored as above. At the end of the 100-day storage period, all teeth were embedded in plaster of Paris and tested for fracture strength at the cervical area in an Instron testing machine. The results showed a decrease in fracture resistance (a) of the incisors with CH in the root canals after 100 days of storage, compared to (b) teeth stored in intracanal saline and (c) teeth with 30 days of CH and then filled with MTA, and (d) those filled with MTA in the canals. In conclusion, when CH was kept in the canals of immature sheep teeth for only 30 days followed by root filling with MTA there was no significant decrease in strength of the root within an observation period of 100 days. This finding may be of importance in the decision of treatment plans for teeth with pulp necrosis and immature root formation.

Aluminum Compounds↗