We evaluated in vitro microleakage of Mineral Trioxide Aggregate (MTA) powder with 4-methacryloxyethyl trimellitate anhydride (4-META) / methyl methacrylate (MMA) & tri-n-butylborane (TBB) resin as a retrograde filling material by using methylene blue dye method. Fifty-two single rooted, extracted teeth were instrumented and obturated with gutta percha and AH plus sealer. The apical 3mm of each root was resected and 3mm deep ultrasonic root end preparation was done. External surface of roots was coated with nail varnish. Prepared teeth were randomly divided into five groups; Negative control: completely covered with nail varnish; Positive control: coated with nail varnish except for apical foramen; Group 1 (retrofilled with Portland cement); Group 2 (retrofilled with MTA); Group 3 (retrofilled with MTA powder mixed with 4-META/MMA & TBB resin). Immediately after completion of root-end filling, all specimens were submerged in methylene blue dye for 72 hours in 37degrees C incubator. The roots were longitudinally sectioned and measured for extent of dye penetration by three different examiners under microscope (x10). The results were statistically analyzed using one way ANOVA and Turkey's HSD test. No leakage was evident in negative control and complete leakage in positive control group. Group 3 showed significantly less leakage than group 1 and 2 (p < 0.01). There was no significant difference between group 1 and 2 (p > 0.01). It was concluded that MTA powder with 4-META/MMA & TBB resin was excellent in reducing initial apical microleakage.
Aluminum Compounds ; Boron Compounds ; Calcium Compounds ; Drug Combinations ; Epoxy Resins ; Glutamates ; Guanine ; Gutta-Percha ; Incubators ; Methylene Blue ; Nails ; Oxides ; Paint ; Root Canal Filling Materials ; Silicates ; Tooth ; Ultrasonics ; Pemetrexed

This study was performed to investigate the biological effects of boron neutron capture therapy (BNCT) on the testes and eyes in mice using HANARO Nuclear Reactor, Korea Atomic Energy Research Institute. BNCT relies on the high capacity of (10)B in capturing thermal neutrons. Sodium borocaptate (BSH, 75 ppm, iv) and boronophenylalanine (BPA, 750 ppm, ip) have been used as the boron delivery agents. Mice were irradiated with neutron (flux: 1.036739E +09, Fluence 9.600200E+12) by lying flat pose for 30 (10 Gy) or 100 min (33 Gy) with or without boron carrier treatment. In 45 days of irradiation, histopathological changes of the testes and eyes were examined. Thirty-three Gy neutron irradiation for 100 min induced testicular atrophy in which some of seminiferous tubules showed complete depletion of spermatogenic germ cells. Lens epithelial cells and lens fiber were swollen and showed granular changes in an exposure time dependent manner. However, boron carrier treatment had no significant effect on the lesions. These results suggest that the examination of histopathological changes of lens and testis can be used as "biological dosimeters" for gauging radiation responses and the HANARO Nuclear Reactor has sufficient capacities for the BNCT.
Animals ; Boranes/*pharmacology ; Borohydrides/*pharmacology ; Boron Neutron Capture Therapy/*methods ; Eye/pathology/*radiation effects ; Histocytochemistry ; Male ; Mice ; Mice, Inbred C57BL ; Neutrons ; Phenylalanine/*analogs&derivatives/pharmacology ; Seminiferous Tubules/pathology/*radiation effects ; Specific Pathogen-Free Organisms ; Sulfhydryl Compounds/*pharmacology

Mineral trioxide aggregate (MTA) was developed in early 1990s and has been successfully used for root perforation repair, root end filling, and one-visit apexification. MTA is composed mainly of tricalcium silicate and dicalcium silicate. When MTA is hydrated, calcium silicate hydrate (CSH) and calcium hydroxide is formed. Formed calcium hydroxide interacts with the phosphate ion in body fluid and form amorphous calcium phosphate (ACP) which finally transforms into calcium deficient hydroxyapatite (CDHA). These mineral precipitate were reported to form the MTA-dentin interfacial layer which enhances the sealing ability of MTA. Clinically, the use of zinc oxide euginol (ZOE) based materials may retard the setting of MTA. Also, the use of acids or contact with excessive blood should be avoided before complete set of MTA, because these conditions could adversely affect the hydration reaction of MTA. Further studies on the chemical nature of MTA hydration reaction are needed.
Aluminum Compounds ; Apexification ; Body Fluids ; Calcium ; Calcium Compounds ; Calcium Hydroxide ; Calcium Phosphates ; Drug Combinations ; Durapatite ; Glutamates ; Guanine ; Hydroxides ; Oxides ; Silicates ; Silicic Acid ; Zinc Oxide ; Pemetrexed

Since its introduction in 1993, Mineral Trioxide Aggregate (MTA) has been shown to be superior to others in sealing, biocompatibility, and many other aspects of clinical endodontics. MTA is primarily Portland cement with bismuth oxide as a radiopacitifier. Although some studies suggested that the reasonable-priced Portland cement could be used instead of MTA, but MTAs are different from Portland cement in its composition, especially in heavy metal contents. Therefore, clinicians should be meticulous adapting the Portland cement as a MTA substitute.
Aluminum Compounds ; Bismuth ; Calcium Compounds ; Drug Combinations ; Endodontics ; Glutamates ; Guanine ; Oxides ; Silicates ; Pemetrexed

The effects of R2O-Al2O3-B2O3-SiO2 system glass and superfine alpha-Al2O3 on the sintering and phase transition of hydroxyapatite (HAP) ceramics were assessed. The results showed that alpha-Al2O3 impeded the sintering of HAP and raised the sintering temperature. When glass and alpha-Al2O3 were used together to reinforce HAP ceramics, better results could be obtained; the bending strength of multiphase HAP ceramics approached 106 MPa when 10% (wt) alpha-Al2O3 and 20%(wt) glass were used and sintered at 1200 for 1 h.
Aluminum Oxide ; chemistry ; Biocompatible Materials ; Boron Compounds ; chemistry ; Ceramics ; chemical synthesis ; chemistry ; Durapatite ; chemical synthesis ; chemistry ; Glass ; chemistry ; Materials Testing ; Silicon Dioxide ; chemistry ; Tensile Strength

OBJECTIVETo observe the expression of inducible nitric oxide synthase (iNOS) in rat dental pulp after direct pulp capping with calcium hydroxide (CH) and mineral trioxide aggregate (MTA).

METHODSSamples from 42 Wistar rats were immediately collected at 1, 3, 7, 14, 21 and 28 days after direct pulp capping with CH and MTA. Pulp tissues were studided with immunohistochemical stain. Software for image analysis was used to test the optical density of each specimen. The data were analyzed by paired t-test and Dunnett-t test with SPSS 11.5.

RESULTSIn normal pulp, the stain of iNOS was negative. After direct pulp capping with CH or MTA, iNOS expression demonstrated weakly positive, positive, weakly positive, negative at different time, the expression was low immediately after capping but became strong after 3 days. Until 7 days the stain became less positive gradually and at 21 days the stain approached normal. The expression was mainly at the fibroblasts, odontoblasts, vascular endothelial cells, neutrophils, etc near the bottom of the pulp capping agent. The diffence of iNOS expression was significant 3 days after direct pulp capping with this two capping agents.

CONCLUSIONAfter direct pulp capping, iNOS expression increasd at first and then decreased, the diffence of capping agents will have an impact on the expression of iNOS 3 days after direct pulp capping.

Aluminum Compounds ; Animals ; Calcium Compounds ; Calcium Hydroxide ; Dental Pulp ; Dental Pulp Capping ; Drug Combinations ; Nitric Oxide Synthase Type II ; Oxides ; Pulp Capping and Pulpectomy Agents ; Rats ; Rats, Wistar ; Root Canal Therapy ; Silicates

The aim of this study was to compare the compositions and cytotoxicity of white ProRoot MTA (white mineral trioxide aggregate) and 3 kinds of Portland cements. The elements, simple oxides and phase compositions of white MTA (WMTA), gray Portland cement (GPC), white Portland cement (WPC) and fast setting cement (FSC) were measured by inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray fluorescence spectrometry (XRF) and X-ray diffractometry (XRD). Agar diffusion test was carried out to evaluate the cytotoxicity of WMTA and 3 kinds of Portland cements. The results showed that WMTA and WPC contained far less magnesium (Mg), iron (Fe), manganese (Mn), and zinc (Zn) than GPC and FSC. FSC contained far more aluminum oxide (Al2O3) than WMTA, GPC, and WPC. WMTA, GPC, WPC and FSC were composed of main phases, such as tricalcicium silicate (3CaO.SiO2), dicalcium silicate (2CaO.SiO2), tricalcium aluminate (3CaO.Al2O3), and tetracalcium aluminoferrite (4CaO.Al2O3.Fe2O3). The significance of the differences in cellular response between WMTA, GPC, WPC and FSC was statistically analyzed by Kruskal-Wallis Exact test with Bonferroni's correction. The result showed no statistically significant difference (p > 0.05). WMTA, GPC, WPC and FSC showed similar compositions. However there were notable differences in the content of minor elements, such as aluminum (Al), magnesium, iron, manganese, and zinc. These differences might influence the physical properties of cements.
Agar ; Aluminum ; Aluminum Oxide ; Calcium Compounds ; Diffusion ; Glutamates ; Guanine ; Humans ; Iron ; Magnesium ; Manganese ; Oxides ; Plasma ; Silicates ; Spectrometry, X-Ray Emission ; Spectrum Analysis ; Zinc ; Pemetrexed

OBJECTIVETo compare the difference in strength degradation and morphology damage of two dental ceramic materials after Hertzian contact cyclic fatigue.

METHODSHertzian contact technique was used to investigate the response of Empress II glass ceramic and GI- II glass-infiltrated alumina ceramic to cyclic fatigue. Critical loads of specimens after different fatigue cycles were recorded.

RESULTSFor Empress II glass ceramic, critical load had significantly difference between specimens after 10(5) cycles loading. No significant difference of critical load was found in GI- II glass-infiltrated alumina ceramic after cycles loading.

CONCLUSIONGI- II glass-infiltrated alumina ceramic has better capability in resistance to cyclic loading. It may attribute to microstructure of material. Empress II glass ceramic shows a brittle damage model.

Aluminum Oxide ; Aluminum Silicates ; Ceramics ; Dental Porcelain ; Glass ; Humans ; Materials Testing

Inositol 1,4,5-trisphosphate receptors (InsP3Rs) modulate Ca2+ release from intracellular Ca2+ store and are extensively expressed in the membrane of endoplasmic/sarcoplasmic reticulum and Golgi. Although caffeine and 2-aminoethoxydiphenyl borate (2-APB) have been widely used to block InsP3Rs, the use of these is limited due to their multiple actions. In the present study, we examined and compared the ability of caffeine and 2-APB as a blocker of Ca2+ release from intracellular Ca2+ stores and Ca2+ entry through store-operated Ca2+ (SOC) channel in the mouse pancreatic acinar cell. Caffeine did not block the Ca2+ entry, but significantly inhibited carbamylcholine (CCh)-induced Ca2+ release. In contrast, 2-APB did not block CCh-induced Ca2+ release, but remarkably blocked SOC-mediated Ca2+ entry at lower concentrations. In permeabilized acinar cell, caffeine had an inhibitory effect on InsP3-induced Ca2+ release, but 2-APB at lower concentration, which effectively blocked Ca2+ entry, had no inhibitory action. At higher concentrations, 2-APB has multiple paradoxical effects including inhibition of InsP3-induced Ca2+ release and direct stimulation of Ca2+ release. Based on the results, we concluded that caffeine is useful as an inhibitor of InsP3R, and 2-APB at lower concentration is considered a blocker of Ca2+ entry through SOC channels in the pancreatic acinar cell.
Acinar Cells ; Animals ; Boron Compounds ; Caffeine ; Calcium ; Carbachol ; Inositol 1,4,5-Trisphosphate Receptors ; Membranes ; Mice ; Reticulum

This study was carried out in order to determine in vitro biocompatibility of white mineral trioxide aggregate (MTA), and to compare it with that of the commonly used materials, i. e. calcium hydroxide liner (Dycal), glass ionomer cement (GIC), and Portland cement which has a similar composition of MTA. To assess the biocompatibility of each material, cytotoxicity was examined using MG-63 cells. The degree of cytotoxicity was evaluated by scanning electron microscopy (SEM) and a colorimetric method, based on reduction of the tetrazolium salt 2,3 bis {2methoxy 4nitro 5[(sulfenylamino) carbonyl] 2H tetrazolium hydroxide} (XTT) assay. The results of SEM revealed the cells in contact with GIC, MTA, and Portland cement at 1 and 3 days were apparently healthy. In contrast, cells in the presence of Dycal appeared rounded and detached. In XTT assay, the cellular activities of the cells incubated with all the test materials except Dycal were similar, which corresponded with the SEM observation. The present study supports the view that MTA is a very biocompatible root perforation repair material. It also suggests that cellular response of Portland cement and GIC are very similar to that of MTA.
Acrylic Resins ; Aluminum Compounds ; Calcium Compounds ; Calcium Hydroxide ; Drug Combinations ; Glass Ionomer Cements ; Glutamates ; Guanine ; Humans ; Hydroxides ; Microscopy, Electron, Scanning ; Minerals ; Oxides ; Silicates ; Silicon Dioxide ; Pemetrexed