Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Calcium Hydroxide”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed2001

Detoxification of endotoxin by endodontic irrigants and calcium hydroxide.

The effects of endodontic irrigants and calcium hydroxide on lipopolysaccharide (LPS; endotoxin) were analyzed using the highly selective technique of mass spectrometry/gas chromatography with selected ion monitoring. An aqueous solution of LPS was mixed with one of a variety of endodontic irrigants for 30 min. Because it is a commonly used interappointment dressing, calcium hydroxide was also applied to LPS for 1, 2, or 5 days. LPS inactivation was measured by quantitation of free fatty acid release. Water, EDTA, ethanol, 0.12% chlorhexidine, chlorhexidine + sodium hypochlorite, and sodium hypochlorite alone showed little breakdown of LPS. Long-term calcium hydroxide--as well as 30-min exposure to an alkaline mixture of chlorhexidine, ethanol, and sodium hypochlorite--did detoxify LPS molecules by hydrolysis of ester bonds in the fatty acid chains of the lipid A moiety.

Bacteriological Techniques↗
PubMed1997

Calcium hydroxide inhibits substrate adherence capacity of macrophages.

The purpose of this study was to investigate the effect of calcium hydroxide on substrate adherence capacity of rat inflammatory macrophages to determine if calcium hydroxide can alter macrophage function. Inflammatory macrophages were obtained from Wistar rats and resuspended in RPMI-1640 medium. Substrate adherence capacity assays were carried out in Eppendorf tubes for 15 min of incubation at 37 degrees C in a humidified atmosphere of 5% CO2. The adherence index (AI) was calculated. Results showed that calcium hydroxide decreased substrate adherence capacity of inflammatory macrophages in a time and dose-dependent manner. The lowest calcium hydroxide concentration that caused a significant inhibition of AI was 1 mM (p < 0.05), and the concentration of calcium hydroxide that caused half-maximal inhibition (IC50) was 1.54 mM (p < 0.01). We conclude that calcium hydroxide decreased substrate adherence capacity of macrophages. When adhesion as the first step in the phagocytic process and in antigen presentation is taken into account, calcium hydroxide could inhibit macrophage function and reduce inflammatory reactions in periapical tissues or in dental pulp when it is used in root-canals therapy or in direct pulp capping and pulpotomy, respectively. Moreover, this effect could explain, at least in part, the mineralized tissue-inducing property of calcium hydroxide.

Animals↗
PubMed1988

[Effects of the treatment of coffee pulp, fresh or ensilaged, with calcium hydroxide, on its nutritive value].

This study was carried out to determine the effects of the addition of calcium hydroxide on the chemical composition and nutritive value of fresh or ensilaged coffee pulp. Fresh or ensilaged pulp were mixed with 1, 2 and 3% of calcium hydroxide. The process was carried out during 0 and 16 hr, after which time the treated pulp was sun-dried for 36 hr until moisture content reached 12%. These samples were then analyzed for their proximate chemical composition and for some minerals (Ca, P, Na, K), as well as for caffeine, tannins and chlorogenic and caffeic acids content. Diets were then prepared from these materials, containing 15% protein and 15 or 30% fresh or ensilaged coffee pulp, and offered to weanling rats during six weeks. Information required on weight gain, food conversion, apparent digestibility and toxicity of the diets was recorded. Results of the chemical analysis revealed that the main changes found in both types of pulp as a result of the calcium hydroxide treatment were the following: a decrease in ether extract (from 4.0 to 2.5 g/100 g), crude fiber (from 18.3 to 11.9 g/100 g) and protein content (from 12.3 to 8.6 g/100 g) in an inverse relation to the amount of calcium hydroxide used. The amount of ash increased, fluctuated between 5.5 and 15.4%, depending on the amount of calcium hydroxide used. The latter affected the Ca:P ratio in the diets, where an average ratio of 7.2:1 was found in the control pulp (0% calcium hydroxide) and 59.0:1 in those treated with the highest amount of calcium hydroxide (3%). Regarding the caffeine, tannins and chlorogenic and caffeic acids contents, calcium hydroxide was effective in decreasing only tannins, more so in the fresh than in the ensilaged pulp; the decrease was in direct proportion to the amount of calcium hydroxide added and to the length of the Ca(OH)2 treatment. The results of the biological assays showed that the addition of Ca(OH)2 in either of the two time periods used and at either of the concentrations studied, did not improve the nutritive value of coffee pulp. There was always a better performance in the animals that consumed ensilaged pulp than in those fed fresh pulp. The animals fed 15% coffee pulp either fresh or ensilaged performed better than those consuming 30% coffee pulp.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2003

pH changes in root dentin after intracanal placement of improved calcium hydroxide containing gutta-percha points.

The in vitro pH changes in root dentin over a period of 2 weeks was investigated in 48 extracted bicuspids after intracanal placement of either Roeko Calcium Hydroxide Plus Points, aqueous calcium hydroxide paste, or gutta-percha points (control group) after root canal preparation. Microelectrodes were placed in outer and inner root dentin at cervical, middle, and apical thirds of the root to measure the pH at 1 h, 2 h, 3 h, 1 day, 3 days, 7 days, and 14 days. Roeko Calcium Hydroxide Plus Points reached a peak inner dentine pH of 11.67 and a peak outer dentine pH of 10.82 at 3 h. In addition, Roeko Calcium Hydroxide Plus Points maintained an outer dentine pH above 9.5 for approximately 2 days, whereas the aqueous calcium hydroxide paste did not reach this pH. However, the alkalinity in dentin with Roeko Calcium Hydroxide Plus Points was maintained for 7 days only, whereas aqueous calcium hydroxide paste maintained an alkaline environment throughout the 2-week period.

Analysis of Variance↗
PubMed1995

Evaluation of long-term calcium hydroxide treatment in avulsed teeth--an in vivo study.

Calcium hydroxide has been advocated for use in avulsed teeth as a temporary dressing in an attempt to prevent or inhibit external resorption. However, there have been no long-term histological studies that have examined gutta-percha versus calcium hydroxide treatment in avulsed teeth. The purpose of this study was to determine the long-term therapeutic effect of calcium hydroxide therapy in avulsed teeth. Six adult macaca monkeys were anesthetized and all four maxillary incisors were extracted and bench-dried for 25 min. The teeth were replanted and splinted with composite for approximately 2 weeks. Each animal served as its own control and the teeth were accessed, instrumented, and filled with either Ca(OH)2 or gutta-percha and AH26 cement. All access openings were filled with composite. The Ca(OH)2 was replaced twice during the experimental period (approximately every 8 weeks). The animals were killed between 5 and 7.5 months post-avulsion. The teeth were removed, sectioned, and examined histologically by two examiners. The results of the histological evaluation of external resorption indicated that there were no statistically significant differences in resorption indices between the teeth obturated with gutta percha or with calcium hydroxide (P > 0.05). Replacement resorption was the primary cause of root destruction and only a few histological sections exhibited evidence of inflammatory resorption.

Animals↗
PubMed2002

Antimicrobial activity of extracts of calcium hydroxide points.

The purpose of this study was to evaluate in vitro the antibacterial effect of calcium hydroxide points by using a broth dilution test. Extracts of calcium hydroxide points and a calcium hydroxide paste (Calasept) were tested by using 2 facultative anaerobic bacteria, Streptococcus mutans (ATCC 27352) and Enterococcus faecalis (ATCC 29212). Saline solution was used as a control. Each tested agent was kept in contact with the bacterial species used for the experiment for 5 minutes, 1 hour, 1 day, 2 days, and 5 days. Results showed that Calasept paste was effective in killing the tested bacteria, whereas calcium hydroxide points and saline showed bacterial survival in all experimental periods. It was concluded that calcium hydroxide points extract is not an effective antimicrobial agent against the tested bacteria.

Administration, Topical↗
PubMed2002

Periapical lesions accidentally filled with calcium hydroxide.

AIM: To evaluate the effect of accidental and voluminous calcium hydroxide overextensions into periradicular lesions and tissues on the prognosis of periapical healing. SUMMARY: Eleven cases with periapical lesions and voluminous calcium hydroxide overextension are presented. Despite literature reports on the deleterious effects of calcium hydroxide extension in the periapical area, none of the endodontic treatments failed and surgical intervention was not indicated. KEY LEARNING POINTS: Extensive extrusion of calcium hydroxide into the periapical tissues does not appear to comprise periapical healing. Despite this finding, the deliberate extrusion of dental materials into the apical tissues is not advocated.

Accidents↗
PubMed1976

Histopathologic evaluation of the effects of four calcium hydroxide liners on monkey pulps.

Pulpal response of four calcium hydroxide liners, MPC 10, MPC 12, Dycal and Pulpdent were tested on primary and permanent teeth with zinc oxide and eugenol (ZOE) and silicate as controls. Responses of the pulps were evaluatedi in Rhesus monkeys, utilizing Class V cavity preparations at 3 days, 5 and 8 weeks. An equivalent number of anterior and posterior teeth were studied for all compounds. The Ca(OH)2 liners, zinc oxide and eugenol (ZOE) and silicate controls were placed in 80 primary and 80 permanent teeth. Following perfusions the teeth were prepared utilizing routine histological procedures. The 3 day response of the calcium hydroxides was moderate with some disruption in the odontoblasts, vacuolization and mild inflammation underlying the cavity except Pulpdent which was more severe. At 5 weeks a decrease in inflammatory response and the formation of reparative dentin was similar for all calcium hydroxides tested at this time period. At 8 weeks more reparative dentin was noted with slight to moderate pulpal responses. At all time periods ZOE produced the least pulpal response while silicate produced the most severe response at 5 and 8 weeks. This study reports the biological responses of four calcium hydroxide compounds used as cavity liners in non-exposures in a series of primary and permanent teeth of monkeys using ZOE and silicate as controls. Responses to the four Ca(OH)2 compounds were moderate for all the experimental compounds except Pulpdent which was more severe at the early time period tested. ZOE produced a milder and silicate a severe response at all periods. All of these compounds were placed by random selection in anterior and posterior teeth of both arches and five teeth were evaluated in both primary and permanent teeth at 3 days, 5 and 8 weeks.

Animals↗
PubMed2001

Calcium concentration and pH of the periapical environment after applying calcium hydroxide into root canals in vitro.

The purpose of the present study was to determine both calcium concentration and pH in the periapical region after application of 1 of 4 different calcium hydroxide preparations into experimental root canals. Fifty root canal models were divided into five groups: group 1--calcium hydroxide was mixed with distilled water at a powder/water weight ratio of 38%; group 2--calcium hydroxide was mixed with distilled water at 44%; group 3--calcium hydroxide was mixed with distilled water at 50%; group 4--calcium hydroxide powder only was used; and group 5-the control group, in which nothing was applied to the canals. All samples were immersed in distilled water maintained at 37 degrees C. Calcium concentration and pH of the distilled water were measured after 3 days, 7 days, and then at weekly intervals up to 15 wk, during which time the storage medium was renewed after each measurement. Calcium concentration and the change in pH of the distilled water were statistically quicker and greater in groups 1 to 3 (mixture groups) than group 4 (powder only) (p < 0.05). The highest calcium concentration (peak Ca2+ release) was observed after 3 days for the mixture groups, whereas that for the powder only group was found at 7 days. Peak pH change was found after 14 days for the mixture groups, whereas that for the powder only group was found at 49 days. After peaking, all groups showed a decline of the pH over time. These results suggest that the time required for optimum intracanal activity when using calcium hydroxide mixtures is at least 2 wk.

Analysis of Variance↗
PubMed2002

Influence of calcium hydroxide intracanal medication on apical seal.

AIM: The aim of this study was to determine the influence of calcium hydroxide intracanal medication and various techniques for its removal on the sealing ability of gutta-percha root fillings with a zinc oxide-eugenol sealer. METHODOLOGY: Eighty extracted mature human mandibular molar roots were divided into three groups of similar root-canal configuration. Calcium hydroxide paste was made by mixing calcium hydroxide powder with distilled water at a powder to liquid ratio of 1:1.25. After root canals were prepared and enlarged to a minimum of size 30 with the Profile 0.06 system, calcium hydroxide paste was placed in the canals of two groups, but no medication was placed in the control group. The intracanal calcium hydroxide was removed with two different techniques, 1 week after medication: K-files one size larger than the master apical file (MAF) were used with 2.5% NaOCl and 15% EDTA solutions in one group, whilst K-files the same size as the MAF were used with 2.5% NaOCl solution in another group. Canals were obturated with gutta-percha and Tubli-Seal cement using the lateral condensation technique. The apical sealing-ability was assessed by dye leakage and cross-sections of the specimens were examined under a stereomicroscope. The dye-penetration level was measured and analyzed using Fisher's exact test and Duncan's multiple range test. RESULTS: The calcium hydroxide-medicated groups showed significantly more dye leakage than the non-medicated control group (P < 0.05). However, there was no significant difference between the two calcium hydroxide-medicated groups (P > 0.05). The stereomicroscopic views showed a relatively uneven and thicker layer of sealer in the calcium hydroxide-medicated groups. CONCLUSION: Calcium hydroxide intracanal medication may increase apical leakage of gutta-percha root fillings when a zinc oxide-eugenol sealer is used.

Calcium Hydroxide↗
PubMed1997

Interaction of calcium hydroxide with zinc oxide-eugenol type sealers: a potential clinical problem.

When a ZnOE type sealer was placed in root canals treated previously with calcium hydroxide dressing, an accelerated sealer setting rate occasionally occurred. This clinical observation led to the present experimental design aiming to investigate the effect of calcium hydroxide on a ZnOE cement and ZnOE type sealers and to preliminarily assess the removal efficiency of a calcium hydroxide preparation from root canal systems. Micro-MIR FTIR spectroscopy was used to quantify the effect of calcium hydroxide on the setting reactions of a ZnOE cement and two ZnOE type sealers. The removal efficiency of calcium hydroxide from root canal systems was evaluated after treatment with NaOCl; NaOCl and filing; and NaOCl plus EDTA and filing. Calcium hydroxide preferentially interacted with eugenol inhibiting the ZnO-eugenol chelate formation. The Ca(OH)2-eugenol interaction was rapid, and kinetically dependent, leading to residual eugenol in the set product. The set ZnOE cement and the ZnOE type sealers in contact with calcium hydroxide were brittle in consistency and granular in structure. Although none of the treatments tested completely removed calcium hydroxide from root canals, treatment with EDTA significantly reduced the extent of residual calcium hydroxide.

Analysis of Variance↗
PubMed1994

Low surface tension calcium hydroxide solution is an effective antiseptic.

The antimicrobial effects of a saturated calcium hydroxide solution, and in combination with 10% and 20% detergent, were evaluated on Streptococcus faecalis, Streptococcus sanguis, Streptococcus mutans, Streptococcus salivarius, Neisseria sp., diphtheroid, Staphylococcus aureus, Lactobacillus sp., Staphylococcus epidermidis, Bacillus subtilis and Candida albicans. The saturated calcium hydroxide solution was effective against only four of the 11 microorganisms studied over a 60-min exposure time. The calcium hydroxide solutions containing detergent killed all 11 test organisms over a 30-min exposure time. This difference was statistically significant (P < 0.01). No statistically significant difference in antimicrobial action was found between the 10% and 20% detergent calcium hydroxide solutions (P > 0.01). However, the low surface tension (46.5 x 10(-3) Nm-1) and high pH (10.8) of the calcium hydroxide solution with 20% detergent establish it as the more effective solution.

Anti-Infective Agents, Local↗
PubMed1996

Comparison of calcium phosphate cement mixture and pure calcium hydroxide as direct pulp-capping agents.

Calcium phosphate cement (CPC) and pure calcium hydroxide were used as direct pulp-capping agents on the deliberately exposed pulp tissue of 60 teeth in five monkeys. Their effects on the pulp tissue of individual teeth were observed and histologically compared after 12, 20 and 24 weeks. The results showed that both materials produced similar responses with regard to their biocompatibility and induction of hard tissue barrier formation. Vasodilatation, chronic inflammation and calcification nidi scattered within the pulp tissue of the 12-week group were observed. Twenty weeks after application of capping materials, a crude reparative dentinal bridge with inclusion of soft tissue or bulky capping agents appeared. A more mature, hard tissue barrier with a better degree of mineralization and formation of dentinal tubules was demonstrated in the 24-week group. The above findings associated with the abilities of self-setting and fair compressive strength suggest that CPC appears superior to pure calcium hydroxide and may have potential for clinical application, although many issues remain to be further investigated.

Animals↗
PubMed1991

Effect of delayed calcium hydroxide treatment on periodontal healing in contaminated replanted teeth.

The effect of delayed intracanal calcium hydroxide treatment on experimentally induced extensive inflammatory root resorption in monkeys was studied. A significant shift from inflammatory resorption to ankylosis was noted following calcium hydroxide treatment. Furthermore, calcium hydroxide treatment appeared to change the pattern of ankylosis over time, although the total ankylotic area remained the same. Ankylosis preceded by root resorption (replacement resorption) increased, while ankylosis not associated with root resorption decreased. It was concluded that intracanal calcium hydroxide treatment of teeth with compromised PDM may cause unnecessary replacement resorption if left in the root canal for a long time or changed repeatedly.

Alveolar Process↗
PubMed2002

Mechanisms involved in the resistance of Enterococcus faecalis to calcium hydroxide.

AIM: This study sought to clarify the mechanisms that enable E. faecalis to survive the high pH of calcium hydroxide. METHODOLOGY: E. faecalis strain JH2-2 was exposed to sublethal concentrations of calcium hydroxide, with and without various pretreatments. Blocking agents were added to determine the role of stress-induced protein synthesis and the cell wall-associated proton pump. RESULTS: E. faecalis was resistant to calcium hydroxide at a pH of 11.1, but not pH 11.5. Pre-treatment with calcium hydroxide pH 10.3 induced no tolerance to further exposure at pH 11.5. No difference in cell survival was observed when protein synthesis was blocked during stress induction, however, addition of a proton pump inhibitor resulted in a dramatic reduction of cell viability of E. faecalis in calcium hydroxide. CONCLUSIONS: Survival of E. faecalis in calcium hydroxide appears to be unrelated to stress induced protein synthesis, but a functioning proton pump is critical for survival of E. faecalis at high pH.

Calcium Hydroxide↗
PubMed1993

Defluoridation of water at high pH with use of brushite, calcium hydroxide, and bone char.

The aim of this study was to improve the efficiency of the bone-char method of water defluoridation by pre-treating the water with brushite and calcium hydroxide. Various amounts of brushite, calcium hydroxide, and bone char were suspended batchwise in 100 mL of distilled water containing 0.53 mmol/L fluoride for 24 h under gentle agitation. At suitable intervals, pH and the concentrations of fluoride, calcium, and phosphate in the water were determined and, when possible, the degrees of saturation with respect to brushite, hydroxyapatite, and fluorapatite calculated. Bone char used alone took up fluoride slowly and inefficiently. The addition of brushite and calcium hydroxide resulted in high concentrations of calcium and phosphate, making the solutions highly supersaturated with respect to fluorapatite, and led to a 20-fold increase in fluoride removal from the water. The combined use of all three salts left low concentrations of phosphate in solution and optimized the fluoride uptake capacity. Repeated use of the same bone char for 18 consecutive runs demonstrated that uptake of fluoride by the bone char was improved by repeated use, provided that brushite and calcium hydroxide were added. Therefore, addition of the two salts to the water may prolong the life of the bone char indefinitely, ensure the removal of fluoride, and thus avoid the problem of determining when the bone char is exhausted. In conclusion, we show that the bone-char defluoridation technique can be improved by addition of brushite and calcium hydroxide to the water. The problem of high terminal pH remains, however, and further work is required to improve potability.

Animals↗
PubMed1994

Continuously infused calcium hydroxide: its influence on hard tissue repair.

To study the ability of calcium hydroxide to promote hard tissue repair, Alza Alzet Osmotic Pumps, implanted in Sprague-Dawley rats, were used to deliver either calcium hydroxide and glycerol, barium hydroxide and glycerol, tetracycline and glycerol, or glycerol only to a standardized round bur defect in a rat femur. The pumps infused one of the reagents into the defects continuously over a 4-wk experimental period. The effects of each reagent on the healing of the bony defects were compared by histological evaluation. The Alza Osmotic Pump proved to be an effective method to deliver an agent to an experimental site. Our preliminary findings from a limited sample size indicated that calcium hydroxide contributed to a more complete osseous repair than either barium hydroxide or tetracycline. Barium hydroxide with a sustained pH equivalent to calcium hydroxide showed no greater healing than the controls. Tetracycline results were also similar to controls.

Animals↗
PubMedDate not supplied

In vitro evaluation of pH changes induced by calcium hydroxide liners.

OBJECTIVES: Since the highly alkaline pH of calcium hydroxide is considered by many to be responsible for its biologic activity, the possible variations of pH induced by the different calcium hydroxide liners are accepted as a major concern. The aim of the present study was to determine the pH changes of five different calcium hydroxide liners and variations of pH levels at different time intervals. METHOD AND MATERIALS: The materials tested were Dycal, Life, Calic, Dycal VLC, and Calcident 450. Samples were prepared according to manufacturer instructions and by using plastic molds; five standard samples from each material were prepared. The samples were then placed in separate vials, containing 10 mL deionized water (pH 7.0), and stored at room temperature (200C). The pH measurements were taken 1 hour, 24 hours, 3 days, and 7 days after mixing. The pH variations of each material at the given time intervals were recorded, and the means were calculated. RESULTS: Statistical analysis showed significantly high differences between the mean pH values induced by each material at all time intervals. The highest value for the first-hour measurement was for Dycal VLC, and the highest values for the other time intervals were for Calcident 450. The pH values of the materials exhibited statistically significant differences among all the time intervals. CONCLUSION: All materials changed the pH of deionized water toward alkaline.

Calcium Hydroxide↗