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PubMed1993

The effect of aluminum hydroxide dissolution on the bleeding of aluminum lake dyes.

The effect of pH on the bleeding of FD&C yellow No. 5 aluminum lake and FD&C red No. 40 aluminum lake was investigated. The pH-bleeding profiles corresponded to the pH-solubility profile of aluminum hydroxide. The similarity of the bleeding profiles of both lake dyes and the pH-solubility profile of aluminum hydroxide indicates that pH related bleeding, other than that occurring by competition with anions, is a result of dissolution of the aluminum hydroxide substrate. This dissolution is related to the properties of the substrate rather than to the structure of adsorbed dye.

Aluminum Hydroxide↗
PubMed2001

Calcium hydroxide retention in wide root canals with flaring apices.

Calcium hydroxide (CH) is used to induce apexification in immature, pulpless teeth with wide root canals and flaring apices. Three placement methods of CH were compared in vitro, for their ability to enhance CH retention in the canal. Barium sulfate (BS), added as radiopacifier, was studied for its effects on the radiographic follow up of CH retention, as well as on the ability to detect voids in the CH. Calcium hydroxide filled teeth were kept in phosphate buffered saline-containing tubes in a shaker water bath. Radiographs were taken weekly to follow the retention or loss of the material; they were scanned and stored as digitized images. Quantitative evaluations were done on these images, using a computerized gray scale. Condensed CH was better retained in root canals than either lentulo-placed paste or commercial injected paste. Barium sulfate in the CH paste enabled better detection of voids in the paste filling the canal, however, it obscured the disappearance of CH from the canal, due to a residual radiopacity effect. The results supported (a) condensation of calcium hydroxide as a preferred method that improves its retention in wide root canals, and (b) discontinuing the use of barium sulfate as a radiopacifier in apexification procedures.

Analysis of Variance↗
PubMed2000

An investigation of the relative efficacy of Buckley's Formocresol and calcium hydroxide in primary molar vital pulp therapy.

OBJECTIVE: To compare the clinical and radiological outcomes following two different, single visit vital pulp therapy techniques, in cariously exposed primary molar teeth. SETTING: A paediatric dental clinic within the Dental Hospital, Newcastle upon Tyne, UK. SUBJECTS: Fifty two child patients were sequentially enrolled in the clinical investigation, 26 males and 26 females with an age range of 3.3-12.5 years. Primary molar teeth requiring vital pulp therapy were randomly allocated to either the formocresol group (F) or the calcium hydroxide group (C). The total number of teeth treated was 84. DESIGN: Recruitment was on the basis of strict inclusion criteria. Coronal pulp amputation was prescribed only in teeth with vital, cariously exposed pulp tissue. Treatment was undertaken between October 1994 and December 1996. All cases were reviewed using predefined clinical and radiological criteria. The statistical tests used were logistic regression of a triple nested data structure, chi-squared analysis of equality of treatment and probability of success with relation to subject age. RESULTS: Eighty-four cariously exposed primary molars required vital pulp therapy. Forty six (55%) teeth were included in the F group and 38 (45%) allocated to the C group. Five teeth were lost to follow-up, leaving 79 teeth: forty four (56%) in group F and 35 (44%) in group C. Eighty four percent (37/44) of teeth treated with formocresol and 77 percent (27/35) treated with calcium hydroxide were classed as clinically and radiographically successful at the cut-off date, December 1997, after a mean clinical review of 22.5 months (range 6.1-38.5 months) and a mean radiographic review of 18.9 months (range 1.3-36.9 months). CONCLUSION: This investigation confirms the clinical efficacy of a one-fifth dilution of Buckley's Formocresol as an agent in pulp treatment of cariously exposed, vital primary molar teeth. However, calcium hydroxide in its pure, powder form is a clinically acceptable alternative when combined with strict selection criteria for this method of restorative care. There was a statistically insignificant difference in successful clinical and radiological outcome between the two treatment groups. Success was unrelated to the duration of time taken to achieve haemostasis and the presence or absence of bleeding after placement of the medicament.

Calcium Hydroxide↗
PubMed1999

Mechanisms of antimicrobial activity of calcium hydroxide: a critical review.

Literature review The primary function of calcium hydroxide as a routine intracanal medicament is to provide antimicrobial activity. However, the mechanisms of antimicrobial activity of calcium hydroxide are not well known. Physicochemical properties of this substance may limit its effectiveness in disinfecting the entire root canal system. In addition, calcium hydroxide is not effective against all bacterial species found in root canal infections. Association with other medicaments may enhance the efficacy of the intracanal medication in eliminating residual bacteria in the root canal system.

Anti-Infective Agents, Local↗
PubMed2000

Influence of calcium hydroxide intracanal dressings on the prognosis of teeth with endodontically induced periapical lesions.

AIM: This prospective clinical study explored the influence of calcium hydroxide as an interappointment dressing on the healing of periapical lesions associated with pulpless teeth that had not been endodontically treated previously. This was achieved by comparing the prognosis after a two-visit root canal treatment with that following a one-visit treatment. METHODOLOGY: Seventy-three patients were recruited having one tooth with an endodontically induced lesion. Of these patients, 67 could be re-examined. Calcium hydroxide was placed in the instrumented root canals of 31 teeth for at least one week and the treatment finished at the second visit. Thirty-six teeth were root canal treated at one visit. The criteria for success were the absence of signs and symptoms indicating an acute phase of periapical periodontitis and radiographically a periodontal ligament space of normal width. Methods for event time analysis were used to evaluate and compare the prognosis of both treatment approaches. RESULTS: The probability that complete periapical healing will take place increased continuously with the length of the observation period. In both treatment groups the likelihood that the root canal treatment yields a success within an observation time of five years exceeded 90%. A statistically significant difference between the two treatment groups could not be detected. CONCLUSIONS: From a microbiological perspective, one-visit root canal treatment created favourable environmental conditions for periapical repair similar to the two-visit therapy when calcium hydroxide was used as antimicrobial dressing. One-visit root canal treatment is an acceptable alternative to two-visit treatment for pulpless teeth associated with an endodontically induced lesion.

Adolescent↗
PubMed2001

Calcium hydroxide in endodontic retreatment after two nonsurgical and two surgical failures: report of a case.

AIM: To describe the role of calcium hydroxide in infection control during complex endodontic retreatment. SUMMARY: A case is presented in which two conventional endodontic treatments and two surgical interventions failed to bring periapical healing. Despite this history, a further conventional treatment augmented by long-term disinfection with calcium hydroxide finally delivered a successful outcome. KEY LEARNING POINTS: Periapical healing follows proper intracanal infection control. Despite repeated surgical and nonsurgical intervention, careful retreatment can often bring healing. Calcium hydroxide has long-acting antimicrobial and soft-tissue dissolving activity. It is a helpful adjunct in endodontic retreatment.

Calcium Hydroxide↗
PubMed2001

Control of microorganisms in vitro by calcium hydroxide pastes.

AIM: The aim of this study was to determine the influence of vehicles on the antimicrobial efficiency of calcium hydroxide. METHODOLOGY: A total of 588 size 50 sterile absorbent paper points, were immersed in various microbial suspensions for 3 min. The points were then placed on Petri dishes and covered with intracanal dressings containing calcium hydroxide: Ca(OH)2 + saline; Ca(OH)2 + camphorated paramonochlorophenol; Ca(OH)2 + 1% chlorhexidine solution: Ca(OH)2 + 3% sodium lauryl sulphate; Ca(OH)2 + Otosporin. After 1 min, 48 and 72 h and 7 days, 147 absorbent paper cones were removed from contact with the intracanal dressings and individually transported and immersed in 5 mL of Letheen Broth, followed by incubation at 37 degrees C for 48 h. Microbial growth was evaluated by turbidity of the culture medium. A 0.1-mL inoculum obtained from the Letheen Broth was transferred to 5 mL of BHI, and incubated at 37 degrees C for 48 h. Bacterial growth was again evaluated by turbidity of the culture medium. Positive BHI tubes were selected and inocula were spread on the surface of BHI agar and incubated at 37 degrees C for 48 h. Gram staining of the BHI growth and from colonies growing on BHI agar was carried out. RESULTS: An antimicrobial effect occurred after 48 h on the cultures of S. mutans, E. faecalis, S. aureus, P aeruginosa, B. subtilis, C. albicans and a mixed culture, irrespective of the intracanal dressing. CONCLUSIONS: Under the conditions of this study, the various vehicles associated with calcium hydroxide pastes did not influence the time required for microbial inactivation.

Anti-Infective Agents, Local↗
PubMed2003

Mineral trioxide aggregate (MTA) and calcium hydroxide as pulp-capping agents in human teeth: a preliminary report.

AIM: To compare mineral trioxide aggregate (MTA) with calcium hydroxide when used as pulp-capping materials in human teeth. METHODOLOGY: Eleven pairs of maxillary third molars in subjects between 20 and 25 years of age were subjected to mechanical pulp exposure. The exposed pulps were capped with MTA or calcium hydroxide, covered with ZOE and restored with amalgam. A total of 14 teeth were extracted after periods of 1 week (two molars) 2 months (three molars), 3 months (five molars), 4 months (two molars) and 6 months (two molars). RESULTS: Histological evaluation demonstrated less inflammation, hyperaemia and necrosis plus thicker dentinal bridge and more frequent odontoblastic layer formation with MTA than calcium hydroxide. CONCLUSIONS: Although the results favour the use of MTA, more studies with larger samples and a longer follow up are suggested.

Adult↗
PubMed2003

The pH changes of four different calcium hydroxide mixtures used for intracanal medication.

The purpose of this study was to determine the pH values of calcium hydroxide mixtures in combination with either distilled water, two different local anaesthetic solutions or physiological saline solution, which are commonly used as a dressing materials during endodontic treatment. The pH of each vehicle prior to mix with calcium hydroxide and subsequently each prepared combination was determined using a digital pH meter. The pH measurements were determined at 3 min, 10 min, 1 h, 24 h, 48 h and 7 days. The results of this study indicated that four different water-based vehicles demonstrated similar pH changes range within pH 11-12 when mixed with calcium hydroxide.

Anesthetics, Local↗
PubMed1997

Nonenzymatic and enzymatic hydrolysis of alkyl halides: a theoretical study of the SN2 reactions of acetate and hydroxide ions with alkyl chlorides.

The SN2 displacements of chloride ion from CH3Cl, C2H5Cl, and C2H4Cl2 by acetate and hydroxide ions have been investigated, using ab initio molecular orbital theory at the HF/6-31+G(d), MP2/6-31+G(d), and MP4/6-31+G(d) levels of theory. The central barriers (calculated from the initial ion-molecule complex) of the reactions, the differences of the overall reaction energies, and the geometries of the transition states are compared. Essential stereochemical changes before and after the displacement reactions are described for selected cases. The gas phase reactions of hydroxide with CH3Cl, C2H5Cl, and C2H4Cl2 have no overall barrier, but there is a small overall barrier for the reactions of acetate with CH3Cl, C2H5Cl, and C2H4Cl2. A self-consistent reaction field solvation model was used to examine the SN2 reactions between methyl chloride and hydroxide ion and between 1,2-dichloroethane and acetate in solution. As expected, the reactions in polar solvent have a large barrier. However, the transition state structures determined by ab initio calculations change only slightly in the presence of a highly polar solvent as compared with the gas phase. We also calibrated the PM3 method for future study of an enzymatic SN2 displacement of halogen.

Acetates↗
PubMedDate not supplied

A comparison of sodium hydroxide and sodium sulfide digestion of mouse hair in the recovery of radioactivity following systemic administration of [3H]-nicotine and [3H]-flunitrazepam.

Pigmented (C57BI) and nonpigmented (balb/c) mice, 25 days of age, were treated intraperitoneally with [3H]-nicotine (4 mg/kg, 555 dpm/ng) or [3H]-flunitrazepam (1 mg/kg, 2200 dpm/ng) daily for three days. After 21 days, shaved back hair was digested at 37 degrees C for 24 h with either 1 M sodium hydroxide or 1 M sodium sulfide. With both drugs, sodium sulfide extraction removed the same amount of radioactivity as sodium hydroxide from nonpigmented hair. However, sodium sulfide removed significantly more radioactivity from pigmented hair than did sodium hydroxide. In pigmented hair, sodium sulfide solubilized 35% and 74% of the flunitrazepam- and nicotine-associated radioactivity, respectively. Of this, 12% and 43%, respectively, could be partitioned into ethyl acetate. Microscopic examination of residual pellets after digestion demonstrated a more thorough dissolution of the hair shaft with sodium sulfide with only melanosomes remaining. The results demonstrate the significant interaction of flunitrazepam and nicotine with melanins and the utility of sodium sulfide in increasing drug recovery.

Acetates↗
PubMed1999

Stabilized polynuclear iron hydroxide is an efficient oral phosphate binder in uraemic patients.

BACKGROUND: There is a continuing need for non-aluminium and non-calcium-containing oral phosphate binders. A novel product, i.e. stabilized polynuclear iron hydroxide, has experimentally been shown to be an effective phosphate binder. The purpose of the study was to test the efficacy and tolerability of the compound in hyperphosphataemic patients with stable preterminal renal failure. METHODS: In an open uncontrolled study we examined a total of 13 patients with stable preterminal renal failure (median serum-creatinine 5.4 mg/dl, range 4.2-7.3 mg/dl) and hyperphosphataemia (median fasting plasma-Pi 2.2 mmol/l, range 1.95 3.0 mmol/l). Patients were given dietary advise to maintain a constant intake of phosphate and this was verified by measuring urinary Pi excretion. After 2 weeks on no oral phosphate binders, patients were given daily 3 x 2.5 g stabilized polynuclear iron hydroxide with meals for 4 weeks. In a blinded fashion plasma-Pi and urinary-Pi as well as 1,84 i-PTH, vitamin D metabolites, serum-iron and ferritin were measured in a central laboratory. RESULTS: Compared to baseline (no oral phosphate binders), the median per cent decrease of fasting plasma-Pi at day 14 was 20% (7.2-41%) (P<0.001 by Wilcoxon test) and the median per cent decrease of urinary P excretion was 37% (9.6-56.6%) (P<0.0003 by Wilcoxon test for paired differences). Ferritin levels did not differ significantly during the study. Apart from a certain laxative action and black discolouration of the faeces, no side effects were noted in this short-term study. CONCLUSION: Stabilized polynuclear iron hydroxide is a promising, efficaceous and well tolerated phosphate binder.

Administration, Oral↗
PubMed2000

Delayed replantation of avulsed mature teeth with calcium hydroxide treatment.

Three avulsed teeth that were replanted and splinted after approximately a 200-min dry extraoral period in two patients are presented. In case 1 calcium hydroxide treatment was performed 1 month after replantation, because the patient did not come for endodontic treatment on the day after replantation as requested. In case 2, calcium hydroxide treatment was initiated on the day after replantation. Calcium hydroxide treatment was used to prevent or treat inflammatory root resorption. During the follow-up periods the teeth reported in these cases have remained in a stable, functional position and did not reveal clinical ankylosis or replacement resorption.

Calcium Hydroxide↗
PubMed2000

A comparison of the surface tension of calcium hydroxide mixed with different vehicles.

The aim of this study was to evaluate and compare the surface tension of different liquids that are used as potential agents to mix with calcium hydroxide in root canal treatment. We also tried to evaluate final surface tension values of the calcium hydroxide mixed with glycerin, Ringer's solution, anesthetic solution, and saline. Surface tension values were measured using a "Du Noüy" tensiometer. The results showed statistically significant differences between vehicles alone and the calcium hydroxide combinations and also indicated that anesthetic solution (p = 0.018, p < or = 0.02) is the most favorable vehicle with the lowest surface tension values.

Analysis of Variance↗
PubMed2000

pH changes in root dentin after root canal dressing with gutta-percha points containing calcium hydroxide.

Alkalinizing action on root dentin was investigated by treating the enlarged root canals of a total of 120 extracted teeth for 24 h, 3 days, or 7 days with either gutta-percha points (size 40) containing calcium hydroxide or an equivalent quantity of aqueous calcium hydroxide suspension. After splitting the teeth longitudinally the pH of the dentin was determined using a pH microelectrode in small cavities at each of four set measuring points. The gutta-percha points were unable to alkalinize the root dentin over a period of 7 days. Clear, rapid, and prolonged alkalinization of the dentin extending through to the root surface was achieved, however, with the aqueous calcium hydroxide suspension.

Alkalies↗
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↗
PubMed2002

Effect of calcium hydroxide on bacterial endotoxin in vivo.

The aim of this study was the histopathological evaluation of apical and periapical tissues in dog teeth that were submitted to bacterial endotoxin, associated or not with calcium hydroxide. After removal of the pulp from 60 premolars, the teeth were divided into four groups and were filled with bacterial endotoxin (group 1), bacterial endotoxin plus calcium hydroxide (group 2), saline solution (group 3), or had induced periapical lesions with no treatment (group 4). After 30 days, animals were killed and the teeth processed histologically. The inflammatory infiltrate, the thickness of the periodontal ligament, and the presence of resorption areas were similar for groups 1 and 4. Groups 2 and 3 were similar to each other. It can be concluded that the bacterial endotoxin caused a periapical lesion and that calcium hydroxide detoxified the lipopolysaccharides in vivo.

Animals↗
PubMed2002

Radiographic evaluation of the effect of endotoxin (LPS) plus calcium hydroxide on apical and periapical tissues of dogs.

The aim of this study was the radiographic evaluation of the apical and periapical region of dog teeth submitted to intracanal bacterial endotoxin (lipopolysaccharide, LPS), associated or not with calcium hydroxide. After removal of the pulp, 60 premolars were divided into four groups and were filled with bacterial endotoxin (group 1), bacterial endotoxin plus calcium hydroxide (group 2), saline solution (group 3), or periapical lesions were induced with no treatment (group 4), for a period of 30 days. Similar periapical lesions were observed in groups 1 and 4. The lamina dura was intact in groups 2 and 3. Bacterial endotoxin (LPS) caused radiographically visible periapical lesions, but when associated with calcium hydroxide, this endotoxin was detoxified.

Animals↗