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At least 613 records · Page 34Linked to original sources
PubMed2006

SEM evaluation of neodentinal bridging after direct pulp protection with mineral trioxide aggregate.

The purpose of this study was to observe the basic morphology and determine the chemical composition of neodentinal bridges adjacent white mineral trioxide aggregate (WMTA) when used as a direct pulp capping material. The experimental procedures were performed on six intact dogs' teeth. The pulps were exposed and cavities were filled with WMTA. After 2 weeks, neodentinal bridge formation was evaluated by scanning electron microscope (SEM) of cross-sections of the specimens and electron probe microanalysis (EPMA) of the pulpal surfaces. Results of SEM observation showed that the most characteristic reaction of pulp cells was the intimate connection of cell processes and secreted extracellular fibres with the crystals of the pulp capping material. Results of EPMA indicated that the mineralisation of neodentinal bridge formation occurred progressively from the periphery to the central area. Based on these results, it appears that WMTA has the potential to be used as a direct pulp capping material during vital pulp therapy.

Aluminum Compounds↗
PubMed2004

Root-end filling materials alter fibroblast differentiation.

UNLABELLED: Root-end filling materials are commonly used following endodontic surgical procedures; however, their effect on adjacent soft tissues is poorly understood. We predict that, due to the differences in their chemical composition, these materials will have profoundly different effects on the survival and differentiation of fibroblasts. Many of the root-end filling materials examined were initially cytotoxic to both PDL and gingival fibroblasts in co-culture experiments; however, this was reduced after the materials were washed in either mineral trioxide aggregate (MTA) or hybrid ionomere composite resin (HICR) for 2 wks. Additionally, PDL fibroblasts displayed enhanced proliferation on MTA and survival on amalgam when compared with gingival fibroblasts. MTA preferentially induced alkaline phosphatase expression and activity in both PDL and gingival fibroblasts. In contrast, HICR inhibited alkaline phosphatase expression and activity. In addition, MTA and HICR repressed pleiotrophin in PDL fibroblasts, while HICR repressed periostin in both fibroblasts. Thus, root-end filling materials differentially affect periodontal fibroblast differentiation. ABBREVIATIONS: mineral trioxide aggregate (MTA), zinc-oxide eugenol cement (ZOEC), hybrid ionomer composite resin (HICR), reverse-transcriptase polymerase chain-reaction (RT-PCR).

Alkaline Phosphatase↗
PubMed2005

Histomorphological response of dogs' dental pulp capped with white mineral trioxide aggregate.

This study was conducted to observe the response of dogs' dental pulp to white mineral trioxide aggregate (MTA) when used as pulp capping material. The pulp of 15 dogs' teeth was experimentally exposed and capped with white MTA. The animals were sacrificed two months later and the specimens were prepared for histomorphological study. The pulp capped with white MTA showed a healing process with complete dentin bridge formation in all samples. In some cases, there was not a tubular dentin shape, but only a structure with an interesting morphological aspect sealing the exposure site. Only 2 specimens exhibited pulp inflammation. In conclusion, the data obtained in this study showed that white MTA has the necessary properties of a pulp capping material.

Aluminum Compounds↗
PubMed2006

In vitro evaluation of apical sealing in root apex treated with demineralization agents and retrofiled with mineral trioxide aggregate through marginal dye leakage.

The purpose of this study was to evaluate the apical seal in root apex treated with different demineralization agents and retrofilled with mineral trioxide aggregate (MTA) using marginal dye leakage. Fifty-six, human single-rooted teeth were instrumented, filled, resected and had retrofilling cavities prepared with ultrasonic tips. Demineralizing agents were applied before the apical cavities were retrofilled with Pro Root MTA. The specimens were assigned to 4 groups (n=14), as follows: group 1 (no demineralizing agent); group 2 (35% phosphoric acid, for 15 s); group 3 (17% EDTA solution, pH 7, for 3 min); and group 4 (24% EDTA gel, pH 7, for 4 min). The extension of dye (2% rhodamine B, at 37 degrees C, for 24 h) penetration was measured in millimeters using a stereomicroscope. Results were statistically analyzed by ANOVA and Tukey's test at 5% significance level. Among the experimental groups, the least extension of dye penetration was observed in group 1 (1.89 mm), followed by groups 2 (2.18 mm), 4 (2.54 mm) and 3 (2.64 mm). No statistically significant differences (p<0.05) were found in marginal microleakage among groups 1, 2 and 4 and groups 2, 3 and 4. Based on the results obtained in this study, it may be concluded that the application of demineralizing agents cannot be recommended when MTA is used in periradicular surgeries.

Aluminum Compounds↗
PubMed2005

In vitro biocompatibility tests of two commercial types of mineral trioxide aggregate.

Recently, regular and white mineral trioxide aggregate (MTA) are being used in Dentistry as retrofilling materials. Genotoxicity and cytotoxicity tests form an important part of cancer research and risk assessment of potential carcinogens. Thus, the goal of this study was to examine the genotoxicity and cytotoxicity of regular and white MTA in vitro by the single cell gel (comet) assay and trypan blue exclusion test, respectively. Mouse lymphoma cells were exposed to two presentation forms of MTA at final concentrations ranging from 1 to 1,000 microg/mL for 3 h at 37 degrees C. The results showed that both compounds tested did not produce genotoxic effects at all concentrations evaluated. Likewise, no statistically significant differences (p > 0.05) were observed in cytotoxicity. Taken together, our results suggest that regular and white MTA are not genotoxins and are not able to interfere in cellular viability as assessed by single cell gel (comet) assay and trypan blue assay, respectively.

Aluminum Compounds↗
PubMed2001

Healing process of dog dental pulp after pulpotomy and pulp covering with mineral trioxide aggregate or Portland cement.

Considering several reports about the similarity between the chemical compositions of the mineral trioxide aggregate (MTA) and Portland cement (PC), the subject of this investigation was to analyze the behavior of dog dental pulp after pulpotomy and direct pulp protection with these materials. After pulpotomy, the pulp stumps of 26 roots of dog teeth were protected with MTA or PC. Sixty days after treatment, the animal was sacrificed and the specimens removed and prepared for histomorphological analysis. There was a complete tubular hard tissue bridge in almost all specimens. In conclusion, MTA and PC show similar comparative results when used in direct pulp protection after pulpotomy.

Aluminum Compounds↗
PubMed2002

Electrical and dye leakage comparison of three root-end restorative materials.

OBJECTIVE: The purpose of this study was to assess three modern root-end restorative materials with electrical and dye leakage tests. METHOD AND MATERIALS: Thirty-three human canine teeth were prepared and filled with gutta-percha and sealer. Stainless steel rods were inserted into the root canals as anodes, and the teeth were varnished. The apical 3 mm of each tooth was resected, and 3-mm root-end preparations were made ultrasonically. Mineral trioxide aggregate, Super EBA, and IRM were used to restore 10 teeth each, and three teeth were varnished as controls. Following 24 hours' setting in blood, the specimens were placed in 1% potassium chloride electrolyte, and leakage was recorded electrically for 70 days. The teeth were then submerged in methylene blue dye for 72 hours, sectioned longitudinally, and scored for leakage by six examiners. RESULTS: In both tests, the mineral trioxide aggregate restorations leaked significantly less than the IRM and Super EBA restorations. Super EBA showed significantly less leakage than did IRM restorations in the electrochemical test but not in the dye leakage experiment. The teeth sealed with mineral trioxide aggregate performed similarly to the varnished negative control teeth. CONCLUSION: The results of this study indicated that mineral trioxide aggregate provides a superior seal in root-end-restorations.

Aluminum Compounds↗
PubMed2005

[Endodontic surgery (apicoectomy)--success rate of more than 90% using dental operating microscope and ultrasonic tips].

The main cause of root canal treatment failure is presence of bacteria in the root canal. Surgical endodontic retreatment is indicated as a valuable treatment choice for failed endodontic treatment. The aim of the article is to describe the advantages of a new technique for apicoectomy using dental operating microscope and ultrasonic tips in comparison to the traditional technique. Precise root end resection with minimal or no bevel and accurate preparation of the root end cavity to the depth of 3-4 mm allows minimal bone removal and reduces procedural accidents such as perforation of the lingual canal wall. Zink oxide eugenol based materials allow sealing of the retrograde preparation adequately to prevent bacteria and toxins to penetrate the periradicular tissues. Literature review demonstrates success rate to above 90% when employing dental operating microscope and ultrasonic tips for retrograde cavity preparation.

Aluminum Compounds↗
PubMed2005

[Retrograde obturation with MTA Cement and Super-EBA after apicoectomy. Sealing ability of MTA and Super-EBA in dye penetration tests].

The present in vitro study investigated the sealing of retrograde fillings compounded of two different cements in consideration of cracking after root-end preparation of resected dental roots using diamond-coated ultrasonic retrotips. Root-end cavities were prepared in 32 resected roots using diamond-coated ultrasonic retrotips. The samples were divided into two groups. The first group was filled using zinc-oxide cement (Super-EBA-Cement), the second with mineral-trioxide-aggregate (Pro Root MTA). After resection, root-end preparation and retrograde filling, the samples were analysed using macro-zoom photography and scanning electron microscopy. The sealing quality of the filling materials was detected through dye penetration test. The average degree of penetration of the samples filled with Super-EBA-Cement was 2.19 and of the samples filled with Pro Root MTA 0.44 respectively. Accordingly the sealing of Pro Root MTA in vitro is superior to the sealing of Super-EBA-Cement. Retrograde conditioning of resected roots with ultrasonic retrotips represents an efficient and sparing alternative to conventional root-end preparation techniques.

Adult↗
PubMed2005

Combined endodontic therapy and surgery in the treatment of dens invaginatus Type 3: case report.

An accurate understanding of the morphology of the root canal system is a prerequisite for successful root canal treatment. Invaginated teeth have a complex root canal configuration that cannot be instrumented effectively and should be treated by both endodontic therapy and surgery. A case of dens invaginatus Type 3 in a maxillary lateral incisor with a periapical lesion and its successful treatment by these combined methods is reported.

Aluminum Compounds↗
PubMed1997

Stimulation of cell proliferation by calcium and a calcimimetic compound.

Some mesenchymal cells respond to stimulation by specific cations with increased cell proliferation. In the present study we have investigated whether the parathyroid/kidney/brain calcium-sensing receptor (PCaR) can mediate such mitogenic responses. We have expressed the recombinant rat PCaR in CCL39 hamster fibroblasts, which do not express a detectable endogenous cation sensor. The transfected cells responded to increased extracellular calcium concentrations ([Ca2+]e) with strong inositol phosphate (IP) formation, which was insensitive to pertussis toxin treatment of cells. We could not detect negative coupling of the receptor to adenylyl cyclase. The calcimimetic NPS R-568 left-shifted the concentration-response curve for [Ca2+]e-induced IP formation and increased the maximal response. In [3H]thymidine incorporation experiments, increasing [Ca2+]e from 1 to 4 mM was found to stimulate DNA synthesis weakly, but significantly. A strong potentiation of this response was observed in the presence of NPS R-568. [Ca2+]e and NPS R-568 also synergized to increase cell numbers in cultures maintained in defined medium. In contrast to our expectations, no significant stimulation of IP formation or cell proliferation could be observed after stimulation of cells with the reported PCaR agonist gadolinium (Gd3+) or with aluminum (Al3+), which stimulates osteoblast proliferation. Gd3+ actually inhibited IP formation stimulated by increased [Ca2+]e as well as by thrombin and AlF4-, indicating toxicity. However, submaximal receptor stimulation by Gd3+ was evident when intracellular calcium transients were measured in fluo-3-loaded cells. Our data show that PCaR can stimulate cell proliferation when expressed in an appropriate cellular context. However, it is unlikely that PCaR mediates the strong mitogenic effects elicited by the cations Gd3+ and Al3+ observed in osteoblasts.

Adenylate Cyclase Toxin↗
PubMed1985

Differential response of muscle and gastric histidine decarboxylase to compound 48/80 and dietary calcium.

Previous work from this laboratory had indicated that in vivo, histidine decarboxylase (HDC) activity was stimulated by compound 48/80 in rat leg muscle, and that high dietary calcium had a stimulating effect on gastric HDC activity. In the present investigations the 48/80 effect was also observed in vitro in leg muscle extracts from rats, chicks, and guinea pigs. Compound 48/80 had no effect in vitro on histamine metabolism of gastric tissue homogenates in any of the animal species studied. A dietary effect of high calcium intake was noted in rat gastric tissue but not in rat leg muscle. In vitro addition of 48/80 and/or calcium had no stimulatory effect on bacterial HDC or on muscle carnosinase activity. These findings, in conjunction with a comparison of stomach and leg muscle mast cell populations, confirm an HDC stimulatory role for 48/80 in muscle, in addition to its histamine-releasing function from mast cells.

Animals↗
PubMed1998

Calcium-deprived rats avoid sweet compounds.

To characterize the link between calcium status and sweet solution intake, rats fed a diet containing 25 mmol Ca2+/kg (Ca-25, low calcium) or 150 mmol Ca2+/kg (Ca-150, control) were given 48-h two-bottle tests with a choice between water and various concentrations of a nutrient (sucrose, Polycose, ethanol and/or corn oil). Rats fed the Ca-25 diet had significantly lower sucrose intakes and preferences over the entire range tested (10-320 g/L) even though the same (Experiment 1), or identically treated (Experiment 2a) rats had normal Polycose and ethanol intakes and normal (Experiment 1, 2b) or significantly greater (Experiment 2a) corn oil intakes. In additional tests, rats fed the Ca-25 diet had significantly lower intakes relative to rats fed the Ca-150 diet of other sweeteners (30 mmol/L D-phenylalanine, 1 mmol/L saccharin and 0.3 mmol/L aspartame), significantly higher intakes of 0.5 mg/L capsaicin and 300 mmol/L monosodium glutamate, and normal intakes of 10 g/L or 80 g/L safflower oil and 10 g/L peanut oil. In a three-cup macronutrient selection experiment (Experiment 3), calcium-deprived rats ate significantly less of a high sucrose carbohydrate source and significantly more of a protein source than did controls. These results suggest that calcium deficiency reduces the rat's liking for sweetness, irrespective of the type or form of sweetener, and that this is not due to a general reduction in energy intake.

Animals↗
PubMed1995

Prevention and reduction of neural damage in ischemic strokes by w-(N,N'-diethylamino)-n-alkyl-3,4,5-trimethoxybenzoate compounds.

Experimental ischemic stroke was induced by an occlusion of middle cerebral artery and common carotid artery of rats for 60 min. The occlusion was then released and the extent of neural damage was measured by the estimation of necrosis areas where the dead neurons lost their ability to take up triphenyl tetrazolium chloride. w-(N,N'-Diethylamino)-n-alkyl-3,4,5-trimethoxybenzoate (TMB) compounds are calcium antagonists capable of reducing intracellular free calcium through inhibition of calcium release from the sarcoplasmic reticulum. These compounds were found to prevent and/or reduce neural damage effectively. When the animals were pretreated with TMB-2, TMB-5 and TMB-8, 1 hr before ischemia, the areas of neural necrosis were reduced almost completely by 95%, 99% and 92%, respectively. When these TMB compounds were given at 0 time and 1 hr after ischemia, the prevention of necrosis was almost complete also. However, when TMB-2, TMB-5 and TMB-8 were administered 6 hr after ischemia, the necrosis areas were reduced less effectively by 83%, 78% and 91%, respectively. TMB compounds were also found to increase cAMP and to reduce intracellular free calcium concentration. These results indicate that TMB compounds are effective calcium antagonists to prevent/treat ischemic stroke by reducing the intracellular free calcium through reduction of calcium release from sarcoplasmic reticulum.

Animals↗
PubMed1984

Evaluation of potassium pyroantimonate/sucrose/glutaraldehyde concentration and incubation time as essential variables for localizing calcium bound to organic compounds in epiphyseal chondrocytes.

The solution chemistry of potassium pyroantimonate (PA) was clarified, enabling preparation of stable concentrated PA solutions. The soluble conjugate base of PA determines the pH of the solution; therefore, the pH reflects the maximum amount of conjugate base dissolved ("saturated") in solution. Spontaneous precipitation occurs just below the "saturation" pH. Sucrose (S) stabilizes the conjugate base exponentially, with precipitation of the sucrose-stabilized PA occurring far below the saturation pH in alkaline solution and at the saturation pH in neutral solution. Using glutaraldehyde (G) at 4% concentration to preserve the cells and using 2-7% PASG solutions at pH 8.5, calcium bound to organic compounds was localized in the hypertrophied chondrocytes at the zone of calcification with optimal reaction. The minimal incubation time for optimal reaction increased with decreasing PA concentration; from 2 hr for 7% PA to 36 hr for 2% PA. With optimal reaction, electron-dense granules were localized in the nucleus, nuclear membrane, endoplasmic reticulum cisterns, mitochondria, Golgi apparatus, intercisternal matrix, plasma membrane, intercellular matrix, and calcospherules. Ethyleneglycoltetraacetic acid immersion and X-ray microprobe studies of the electron-dense granules indicated calcium as the predominant cation. Control tissues with implanted tricalcium phosphate crystals, and reaction kinetic between PA and cellular calcium, indicated that the calcium localized was not due to translocation but to calcium bound to organic compound that is synthesized by the hypertrophied cells in the zone of calcification.

Animals↗
PubMed1992

Effects of antiepileptic drugs, calcium channel blockers and other compounds on seizures induced by activation of voltage-dependent L calcium channel in DBA/2 mice.

1. The convulsant activity of the calcium voltage L-channel agonist Bay k 8644 was studied in genetically epilepsy prone DBA/2 mice. 2. Seizures were induced by intracerebroventricular injection of Bay k 8644. 3. These seizures were reversed by some calcium channel blockers such as dihydropyridines, some excitatory amino acid antagonists such as 2-amino-7-phosphonoeptanoate and CPPene, 2-chloro-adenosine, some anticonvulsant drugs such as magnesium valproate, diazepam and clonazepam and two kappa opioid agonists (U-50488H and U-54494A). 4. The remaining antiepileptic drugs (carbamazepine, phenytoin, phenobarbital and trimethadione) were ineffective in this respect. Other anticonvulsant compounds such as dizocilpine (MK 801), ketamine and drugs enhancing GABAergic transmission did not significantly affect the clonic phase of the seizures induced by Bay k 8644. 5. These results show that Bay k 8644 seizures are relatively resistant to some anticonvulsant compounds. The role of some neurotransmitters on seizures induced by Bay k 8644 is discussed.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗