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PubMedDate not supplied

Mast cells in tissue response to dentistry materials: an adhesive resin, a calcium hydroxide and a glass ionomer cement.

Synthetic materials used in dentistry may trigger various inflammatory responses. In order to evaluate biocompatibility, standardized implants of Calcium Hydroxide (CH), Glass Ionomer Cement (GIC) and Light-activated Dental Adhesive (LDA) were surgically introduced into Wistar rats' back bone. Six (experimental) animal groups, five each, and two Sham (S) groups were studied after 15 and 30 days from surgery. In each animal, the density of mast cells and interstitial fibrosis volume was evaluated by quantitative light microscopy. In addition, the interaction between the disk material and its fibrous capsule was evaluated by scanning electron microscopy. The density of mast cells per area (N(A)[mast cells]) was lower in CH group than in LDA group. GIC group displayed N(A)[mast cells] results intermediate between CH and LDA groups (p<0.05). The smallest interstitial fibrosis volume density (Vv[f]) was observed in CH group, then in GIC group, while the greatest in LDA group. After 30 days, the fibrosis in LDA group was 30% higher than in CH group (p<0.05). In S group, discreet fibrosis restricted to surgical area was present, with few mast cells near the vessels. Significant interaction between fibrous capsule and the surrounding disk material was most evident in CH group. The implanted materials induced mast cell migration, distinct fibrosis development, suggesting that CH is the most biocompatible material among those tested.

Animals↗
PubMed1977

Changes in vitamin A conditioned hamster cheek pouch epithelium on exposure to commercial shell lime (calcium hydroxide) and tobacco. I-Optical histopathology.

Epidemiologically a high incidence of oral cancer and addiction to tobacco, singly or in combination with other ingredients of the betel quid, are closely correlated. Attempts at the induction of malignancy in laboratory animals on exposure to these ingredients have hitherto failed. Studies are reported on cheek pouch epithelium of 152 Syrian golden hamsters exposed to commercial shell lime (calcium hydroxide) and tobacco, singly and in combination, with parallel conditioning by Vitamin A palmitate. The abnormal changes found especially in lime and lime-plus-tobacco treated epithelia are massive hyperplasia, keratinization anomalies, marked edema and dysplasia. The most significant findings are (1) greater epithelial alteration caused by lime, lime plus vitamin A, tobacco plus vitamin A, lime plus tobacco and lime plus tobacco and vitamin A, than by tobacco alone; (2) increasing epithelial dysplasia in response to longer periods of exposure to the test substances; and (3) enhancement of tissue changes in the presence of vitamin A.

Animals↗
PubMedDate not supplied

Inability of calcium hydroxide to induce reparative dentinogenesis at non-peripheral sites of dog dental pulp.

The ability of 2 calcium hydroxide-containing materials to induce initiation of reparative dentinogenesis was tested at sites remote from the dentinogenically-active regions of the pulp periphery. Pieces of the cements, Dycal and Life, were implanted in central parenchymal sites of dog dental pulps for periods of 6, 14 and 42 days, respectively. Similar pieces were placed in peripheral capping sites as controls. The responses were analyzed by light and transmission electron microscopy. Induction of tubular dentin matrix lined with elongated and polarized odontoblast-like cells was only seen at peripheral capping sites. In response to the centrally implanted cements, only atubular hard tissue with lining fibroblast-like cells was deposited.

Animals↗
PubMed1996

Effect of aluminium hydroxide administration on normal mice: tissue distribution and ultrastructural localization of aluminium in liver.

In order to assess the risk of parenteral aluminium (Al) exposure, we evaluated the effects of intraperitoneal administration of aluminium hydroxide, a compound widely used in medicine. Mice (strain Pzh:SFIS) received intraperitoneally, every two weeks 1 mg Al or 0.1 mg Al for five days a week. Controls received injections of saline. Al concentrations in liver, bone and brain were evaluated by electrothermal atomic absorption spectrometry after exposure to 2 mg, 4 mg, and 6 mg Al. The concentration was the highest in liver and occurred after exposure to only 2 mg Al (265.1 +/- 27.7 mg/kg, 233.5 +/- 28.0 mg/kg). Generally further accumulation was not dose- and treatment-dependent. The only exception was a significant Al increase in the liver after exposure to 6 mg Al, injected 0.1 mg Al five days/week. Development of resorption granulomas was observed in the liver, Al being revealed by Morin fluorescence in constituent macrophages and giant cells. By electron probe X-ray microanalysis, Al was identified predominantly in lysosomes of macrophages and Kupffer cells. In tibia of mice, a dose-dependent Al accumulation was observed. The highest level of Al concentration after the 6 mg treatment was 23.5 +/- 3.82 mg/kg and 25.06 +/- 2.3 mg/kg. The Al concentration in the brain of mice had not changed significantly during Al treatment.

Aluminum↗
PubMed1991

Neurotoxic effect of two root canal sealers with calcium hydroxide on rat phrenic nerve in vitro.

Root canal sealers placed into contact with the inferior alveolar nerve can cause paraesthesia in the area innervated by this nerve. The paraesthesia is due to neurotoxic effects of the sealers. In this study we examined the effect on nerve conduction in vitro of two calcium hydroxide-containing root canal sealers, Sealapex and CRCS. An isolated rat phrenic nerve was placed between two suction electrodes in a bath containing Tyrode solution. The sealers were brought into contact with the nerve, and the evoked compound action potentials (cAP) were recorded before and after contact with the materials. Both Sealapex and CRCS induced a fast and complete inhibition of the cAP in this model. The degree of reversibility of the inhibition varied from experiment to experiment. Both materials exhibited reversible and irreversible block of the nerve conduction after 90s and 5 min exposure. However, after 30 min of contact, the conduction of the cAP was irreversibly blocked for both materials.

Action Potentials↗
PubMed1994

Timing of calcium hydroxide therapy in the treatment of root resorption in replanted teeth in dogs.

The effect of time of the onset of calcium hydroxide (CH) pulpectomy on root resorption of 31 permanent dog incisors was investigated. CH pulpectomy was delayed 4, 9, 14 and 18 days after the teeth were extracted and replanted. Control teeth were replanted 1) without pulpectomy, 2) with a pulpectomy only or 3) with a pulpectomy and CH filling. All teeth were prepared for histologic evaluation 8 weeks after the teeth were replanted. Cross section were examined using a computer microscope and linear (micron) and/or square areas (micron 2) of surface (SRR), inflammatory (IRR), and replacement (RRR) root resorption were calculated. From this data the percentage of linear and area resorption was averaged for each group. Duncan multiple range t-test (P < or = 0.05) revealed that teeth in which a pulpectomy with CH filling was done extraorally had significantly greater SRR than the rest of the groups; teeth in which a pulpectomy without CH filling was done extraorally had significantly greater RRR than teeth in which CH pulpectomy was delayed for 18 days; there was no significant difference in SRR, IRR or RRR when CH placement was delayed 4, 9, 14 or 18 days after replantation. Although it was not significant the overall resorption was least when CH pulpectomy was delayed 18 days.

Animals↗
PubMed1994

Histological observations of hard tissue barrier formation in amputated dental pulp capped with alpha-tricalcium phosphate containing calcium hydroxide.

This study was performed to evaluate the pulpal response to alpha-tricalcium phosphate (alpha TCP) containing calcium hydroxide (Ca(OH)2). The dental pulps of monkeys were amputated and dressed with four agents: alpha TCP, alpha TCP containing 1% Ca(OH)2, alpha TCP containing 5% Ca(OH)2, and Ca(OH)2 being used as a control. The pulpal responses were histologically evaluated after 4 and 8 weeks. The pulp tissue treated with alpha TCP proliferated above the level of the original wound surface, and a thin layer of hard tissue barrier was formed directly against the capping agent. The barrier demonstrated atubular matrix lined with flattened or cuboidal cells, but occasionally appeared irregular in form. Ca(OH)2 dressing resulted in destruction of pulp tissue, with a thick hard tissue barrier being formed below the level of the exposure site. The barrier consisted coronally of osteodentin and pulpally of tubular dentin lined with odontoblast-like cells. By contrast, 1% Ca(OH)2 added to alpha TCP produced a slight proliferation of pulp tissue. An atubular matrix barrier, pulpally lined with cuboidal cells, formed above the exposure site. It was later followed by the formation of tubular matrix lined with columnar cells. Teeth treated with 5% Ca(OH)2 showed a thin necrotic layer and a thick barrier formation. The barrier was composed of tubular dentin-like tissue lined with odontoblast-like cells. It would appear that alpha TCP containing a small amount of Ca(OH)2 may be clinically useful as a capping agent, as it induced consistent hard tissue formation, without excessive destruction of underlying pulp tissue.

Animals↗
PubMed1995

In vitro evaluation of the cytotoxicity of calcium hydroxide-based root canal sealers.

The cytotoxicity of three calcium hydroxide-containing root canal sealers (Sealapex, CRCS and Apexit) was tested by using L929 and BHK 21/C13 cells. After setting for 24 h, the sealers were covered with cell suspension. Cytotoxicity was determined by a quantitative technique at 24 h, 48 h and 72 h. All the sealers were found to be cytotoxic. Sealapex showed the highest cytotoxicity, causing a significant decrease in cell density. CRCS was less toxic than Sealapex and more toxic than Apexit. Apexit proved to be the least toxic material.

Animals↗
PubMed1999

The antimicrobial effect of calcium hydroxide in root canals pretreated with 5% iodine potassium iodide.

Calcium hydroxide (CH) is often used as a routine interappointment dressing during the endodontic treatment of teeth with apical periodontitis. However, it fails to consistently produce sterile root canals. The present study was set up to find out whether an antimicrobial strategy including the use of CH could be made more effective if: 1) canals were pretreated with 5% iodine potassium iodide (IPI), and 2) the dressing period was extended up to 2 months. Fifty human teeth, with radiographically verified apical periodontitis, were microbiologically sampled. After chemomechanical preparation the canals were pretreated with IPI for 3-7 days. Teeth where microorganisms persisted were then treated with CH for 2 months. Following instrumentation and dressing with IPI, 43 bacterial strains were recovered in 22 of the teeth. Samples obtained after the CH dressing period disclosed growth of 13 facultative and two strict anaerobic strains in 10 teeth. Enterococcus faecalis was identified in two specimens. In conclusion, the present study gave no evidence for an increased antimicrobial effect of CH if it was left for longer periods in the root canal. Although pretreatment with IPI from a quantitative point of view did not seem to add antimicrobial power, it might reduce the frequency of persisting strains of E. faecalis.

Adult↗
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↗
PubMed2005

Study of calcium hydroxide apexification in 26 young permanent incisors.

This study was carried out in order to observe the effectiveness of apexification in young permanent incisors. The sample comprised 26 young permanent incisors with necrotic pulp and open apices. The time taken to obtain apical closure, its form and size were analysed in order to find out if closure was influenced by existing pathology or size of apex. The treated teeth were compared with their corresponding contralateral teeth. The test of McNemar and anova was used and a result of P = 0.05 was considered significant. Teeth with pretreatment apical shapes that were convergent or parallel all resulted in physiological apical shapes after treatment. Eight teeth had divergent apical shapes before treatment. Of these, one had a physiological shape, five ended with rounded apices and two teeth had straight apices post-treatment. Apical closure was obtained in 100% of the cases studied, of these 88.4% needed three to four sessions of calcium hydroxide treatment (an average of 3.23 sessions) in order to obtain apical closure, the average time employed was 12.19 months. Clinical symptoms resolved in all teeth that presented with symptoms. Preoperative symptoms did not affect outcome. Pathology of the tooth before treatment does not influence the time needed to obtain apical closure.

Analysis of Variance↗
PubMed2005

Histological comparison of alendronate, calcium hydroxide and formocresol in amputated rat molar.

The purpose of this study was to evaluate the potential of alendronate sodium (ALN), a biphosohonate to stimulate hard tissue formation in pulpotomized (amputated) rat molars. Two commonly used pulpotomy materials, calcium hydroxide (CH) and formocresol (FC) were utilized for comparisons. Histological evaluations were performed by observers blinded to treatment allocation on days 7, 15, 30 and 60, followed by statistical analysis of selected histological criteria. In all evaluation periods, hard tissue deposition was evident along the radicular dentin in ALN and CH groups. In days 30 and 60, the latter two groups showed no differences in inflammatory cell response and hard tissue deposition scores (P > 0.05). ALN appears to be capable of maintaining pulpal vitality, while promoting hard tissue formation, similar to CH.

Alendronate↗
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↗
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↗
PubMed1980

Dialysis encephalopathy in a non-dialysed uraemic boy treated with aluminium hydroxide orally.

Brain aluminium concentration has been found significantly higher in patients dying with dialysis encephalopathy than in uraemic patients without this syndrome, and it has previously been reported only in haemodialysed patients. We report a case of high brain aluminium concentration in a uraemic boy showing symptoms of severe encephalopathy. He was never dialysed but only treated with aluminium hydroxide orally. Baluarte reported corresponding symptoms in nondialysed uraemic children, but brain aluminium concentrations were not reported. His patients as well as our had very high levels of parathormone which may play a role in the resorption and distribution of aluminium. Aluminium preparations should be avoided in children with renal failure.

Administration, Oral↗
PubMed1983

The effect of direct current, sodium hydroxide and hydrochloric acid on pig epidermis. A light microscopic and electron microscopic study.

Lesions in pig skin were induced by direct current, hydrochloric acid and sodium hydroxide, and the morphology of the lesions was compared in order to establish the influence of electrolysis in the electrical lesions. Both light microscopically and electron microscopically a pronounced similarity was found between cathode lesions and base-induced lesions including the presence of vesicular nuclei in both kinds of lesions. Some features were also common to anode lesions and acid induced lesions, but dissimilarities were present as well. From the results it is concluded that electrolysis in the tissue with the subsequent shift of pH, especially towards the alkaline side, is responsible for the formation of the vesicular nuclei which we repeatedly have found to be characteristic of electrical skin lesions. The shift of pH also induces the cytoplasmic feature called "white necrosis" which therefore is found more regularly in electrical lesions than in heat lesions.

Animals↗
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↗
PubMed1967

Pemoline and magnesium hydroxide: lack of effect on RNA and protein synthesis.

Brain RNA polymerase isolated from rats treated with pemoline and magnesium hydroxide (Cylert) was not more active than enzyme from control animals. The drug did not increase enzymic activity in vitro. Pemoline did not significantly affect either RNA or protein synthesis in suspensions of Ehrlich ascites carcinoma cells.

Animals↗