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At least 991 records · Page 55Linked to original sources
PubMed1995

[Assessment of effectiveness of AgSD-ZnSD-Azone cream, negative ion irradiation and "moisture burn ointment" in prevention of burn wound infection as judged by changes in LPS, TNF and ET levels].

40 Wistar rats were scalded resulting in 15% TBSA full-thickness burn. Pseudomonas aeruginosa (10(9)/ml) was seeded on the wounds. The animals were divided into 4 groups. AgSD and ZnSD (with Azone) cream was applied to the wounds in the group I. The wounds were irradiated with negative ion current in the group II. The "moisture burn ointment" was applied to the wounds in the group III. Group IV consisted of controls without any treatment. Judging by changes in levels of LPS, TNF and ET, it was shown that the best result was obtained in the group I and II. The "moisture burn ointment" group yielded the poorest results.

Animals↗
PubMed1996

A pilot study of the marginal adaptation and surface morphology of glass-cermet cements.

This study investigated changes in the marginal adaptation and surface morphology of Ketac-Silver and Chelon-Silver glass-current cements over time. Dispersalloy amalgam was used as a control. Contralateral pairs of carious primary molars were restored with the test materials and amalgam. Clinical evaluations were scheduled at 12, 18, and 24 months after placement. Gold-plated replicas of the restorations were observed with scanning electron microscopy. Fractures and cracks in the surface of the Dispersalloy and Chelon-Silver increased the surface roughness; however, the damage was superficial and self-limiting in the Dispersalloy restorations, while in Chelon-Silver the fractures caused the material to break down in layers. A substantial quantity of pores, usually smaller than 50 microns in diameter, were observed throughout the surface of the Chelon-Silver restorations. The pores in the surface of Ketac-Silver were fewer and smaller. The incidence of cavomarginal breakdown increased with time. Chelon-Silver restorations had a higher rate of cavomarginal breakdown than did Ketac-Silver and Dispersalloy restorations up to 18 months. However, there was no statistically significant difference in the marginal adaptation of the three groups at 24 months.

Cermet Cements↗
PubMed1997

Use of a catecholamine sensor in the control of an artificial heart system.

An electrochemical sensor system to allow real-time measurement and feedback of catecholamine concentrations was developed for use in the control of artificial hearts. Electrochemical analyses were carried out using a carbon fiber working electrode, an Ag-AgCl reference electrode, and a potentiostat. The operating parameters of the pneumatically-driven artificial heart system were altered in accordance with the algorithm for changes in the catecholamine concentration. The minimum detectable concentrations of both adrenaline and noradrenaline in a mock circulatory system using a phosphate-buffered solution were approximately 1-2 ng/ml (10(-8) mol/L). An artificial heart control system utilizing this set-up performed satisfactorily without delay, although sensor sensitivity decreased when placed in goat plasma instead of a phosphate-buffered solution, due to the adsorption of various substances such as plasma proteins onto the electrodes. This study demonstrated the future feasibility of a feedback control system for artificial hearts using catecholamine concentrations.

Adsorption↗
PubMed1996

Tunnel restorations using glass ionomer or glass cermet: in vitro marginal ridge fracture and microleakage.

The purpose of this in vitro study was to compare the marginal ridge fracture resistance and microleakage following restorations of partial tunnel preparations using glass ionomer and glass cermet cements. Sixty eight sound premolars were selected for this study and were divided randomly into six groups. A standardized partial tunnel preparation was done on all the teeth except specimens belonging to Group I. The partial tunnel preparations of Groups III & V were restored with glass ionomer and that of Groups IV & VI were restored with glass cermet. The teeth belonging to Groups I, II, III & IV were subjected to marginal ridge fracture resistance testing. The teeth of Groups V & VI were tested for microleakage after immersing them in 5% methylene blue solution for 4 hours. The results indicated that the teeth restored with glass cermet were marginally better than that with glass ionomer in terms of marginal ridge fracture resistance. Both the materials failed to reinforce the marginal ridge to the level of an intact tooth. The microleakage which occurred around both the materials were statistically insignificant, but on comparison glass ionomer showed better results. Hence, glass ionomer is preferred as a restorative material for partial tunnel preparations because of additional inherent advantages like superior esthetics and fluoride leachability.

Bicuspid↗
PubMed1996

[Evaluation of the long-term release of fluorides from type II glass ionomer cements with conventional setting reactions].

As a part of a fundamental investigation on the fluoride release of glass ionomer cements (GIC), this study investigates the operator dependency of the fluoride release. In this respect the GIC fluoride release of a classical powder-liquid based system (Fuji II) and a capsule-based system (Fuji Cap II) in water during 14 days was determined on the hand of 5 specimens per formulation, made by 5 different operators. The data reveal that the variance on the fluoride release as well as the mean fluoride release at a given time are independent of the operator for both Fuji II and Fuji Cap II. In order to derive fundamental factors affecting the GIC fluoride release, the long-term fluoride release of 10 conventional setting type II GIC is investigated. In this respect the fluoride release profiles (FRP) of each of 5 cylindrical specimens (d = 6 mm, h = 3 mm) of Fuji II (FP), Fuji Cap II (FC), Miracle Mix (MM), Chemfil II (CP), Chemfil II in caps. (CC), Chelon-Fil (CF), Ketac-Fil (KF), Shofu II (SH), Chelon-Silver (CS) and Ketac-Silver (KS) were determined. The specimens were made according to the manufacturer's instruction and equilibrated at 37 degrees C in 25 mL distilled water up to 140 days. The water was regularly renewed and the fluoride concentration [F] of the equilibrated solution determined. A Multivariate Data Analysis of the [[F], t]-profiles on the basis of Principal Component Analysis (PCA) reveals that the FRP can be classified into 4 distinct groups: [CS,KS,FP]-[FC,CC]-[CF,KF] and [MM], leaving SH and CP apart as unclassifiable. When the cumulative amount of fluoride released ([F]c) for each individual sample is calculated and fitted as a function of time, a regression analysis shows that [F]c is most adequately fitted (r > 0.99) by [F]c = [F]I/t+t1/2 + beta, square root of t, indicating that 2 kinetic processes are responsible for the FRP. A comparison of the parameters of this equation ([F]I, t1/2 and beta) shows that the physicochemical rationale for this classification of the GIC conforms to differences in the kinetics of these processes. From the classification, it becomes apparent that different formulations can result in the same FRP.

Capsules↗
PubMed1997

Comparison of surface EMG signals between electrode types, interelectrode distances and electrode orientations in isometric exercise of the erector spinae muscle.

The influence of electrode type, interelectrode distance (IED) and electrode orientation on EMG signals from the paraspinal muscles was investigated. Bipolar electrodes were placed at distances 2, 3, 4, 6 and 8 cm over the erector spinae in the cranio-caudal direction ("in series") as well as in the direction perpendicular to it ("in parallel"). Ten subjects performed 5 s isometric contractions of the erector spinae at 20, 40, 60, 80 and 100% MVC by pulling upward on a handlebar attached to the floor. RMS EMG signals were analyzed for mean average amplitude (AA). Mean total power (TP) and mean median frequency (MF) of the raw EMG signal were determined using fast Fourier transform. In addition to graded loading, sustained fatiguing contractions were performed from which TP and MF were obtained. With increasing IED the AA and TP increased while MF decreased. Although a trend towards higher AA, TP and MF was found for electrodes "in series", as compared to those "in parallel", the difference never reached significance. It is concluded that consistent information about muscle activity was obtained with Miniature Biopotential Skin Electrodes and 14445C Hewlett-Packard electrodes independently from IED or orientation. Orientation "in parallel" prevented the electrodes from sliding during muscle contraction. The third tested type, electrodes developed in the Neuromuscular Research Center, Boston, proved extremely sensitive to movement.

Adult↗
PubMed1997

Surface texture and enamel-restoration interface of glass ionomer restorations.

The aim of this study was to investigate the surface texture and enamel-restoration interface of Class II glass ionomer restorations in primary molars. A traditional (Chemfil II), a cermet (Chelon-Silver) cement and two light cured glass ionomer cements (Vitremer and Dyract) were used to restore the Class II cavities of 20 primary molars. The surface changes and enamel-restoration interface of restorative materials were evaluated by SEM, after a 12 month period. Microcracks and pores in surface were observed in all of the four different glass ionomer materials. Although, there was no marginal gap formation for Chemfil II, Chelon-Silver and Dyract samples, in 2 samples of Vitremer group gap formation was found with an ion-exchange layer. Also, in Dyract samples wear of restorations was considerable.

Cermet Cements↗
PubMed1997

Marginal ridge fracture resistance, microleakage and pulpal response to glass ionomer/glass cermet partial tunnel restorations.

Sixty sound premolars which were to be extracted for orthodontic treatment purposes were restored either with glass ionomer cement or glass cermet cements after partial tunnel preparation, and prior to the extraction after a time interval of 30 and 60 days respectively. The teeth were then subjected to marginal ridge fracture resistance, microleakage study using dye penetration and histological evaluation of the pulpal response to these materials. Both the materials exhibited increase in marginal ridge fracture resistance at 60 days, with minimal degree of microleakage and were biologically compatible with the dental pulp.

Bicuspid↗
PubMedDate not supplied

Fluoride release from fluoride-containing materials.

This in vitro study evaluated the amount of fluoride released from fluoride-containing materials over a period of 28 days. Six disk samples (2.06 +/- 0.06 cm2) were prepared of each material and divided at random into seven groups: Group 1: Chelon-Fil; Group 2: Chelon-Silver; Group 3: VariGlass; Group 4: Dyract; Group 5: Vitremer; Group 6: Vitremer + Scotchbond Multi-Purpose; Group 7: Fuji II LC. The cements were mixed according to the manufacturers' recommendations, placed in plastic molds, and pressed between two glass plates. Paraffined dental floss was incorporated into the cements during setting to serve as attachments. The materials in Groups 3, 4, and 5 were light cured (Heliolux) in two different positions for 40 seconds each. In Group 6, the adhesive was light cured in two different positions on both sides for 10 seconds each. The samples were stored at 100% relative humidity for 24 hours. Each sample was then suspended in individual plastic tubes containing 5 ml of deionized water and submitted to constant agitation at 25 degrees C. The water was changed every 24 hours. Fluoride release was determined at 1, 2, 3, 4, 5, 7, 14, and 28 days after buffering the solution with equal volume of TISAB. Fluoride release was measured with a fluoride ion-specific electrode (Orion 96-09) and an ionanalyzer (Orion EA 940) previously calibrated with standard solutions containing 0.05 to 5.00 micrograms F/ml. Fluoride release was expressed as ppm in solution and micrograms F/cm2. ANOVA and Student-Newman-Keuls tests were used to evaluate the data. The results revealed that Chelon-Fil released significantly (P < 0.001) more fluoride for the first 7 days than all the other products. This was followed by Fuji II LC, which exhibited significantly more fluoride release than the rest of the materials for the same 7 days. At days 14 and 28, Chelon-Fil, Dyract, and Fuji II LC released similar amounts of fluoride that were significantly greater than the other products. Group 6 (Vitremer + Scotchbond Multi-Purpose) released significantly less fluoride than the other materials at all time intervals. Fluoride release for all products at days 1 and 2 was significantly greater than the rest of the time intervals, except for Chelon-Silver, which released similar amounts of fluoride for days 2, 3, 4, and 5. Although significance for the remaining time intervals varied for all materials, all fluoride release decreased from day 1 to day 28.

Acrylic Resins↗
PubMed1997

Promising new dental materials on the horizon.

The rapidly evolving field of materials science is providing dentistry with new treatments and alternatives. Calcium phosphate materials are under development for bone repair and replacement, root surface desensitization, and for caries prevention, by greatly increasing the remineralizing efficiency of fluorides. Composites fabricated from calcium phosphates and polymers may have application as pulp capping and cavity-basing materials. An alternative to mercury dental amalgam is being investigated; it is composed of silver powders that are cold-welded in the presence of a dilute acid. These materials are only a few of the technologies that may profoundly affect the future delivery of dental care.

Animals↗
PubMed1998

High performance Nanogold-silver in situ hybridisation.

Conventional in situ hybridisation (ISH) usually requires the presence of at least 10-50 copies of the nucleic acid sequence in question per cell. In situ PCR has been proposed as an alternative method, which may yield single-copy sensitivity, but shows a relatively high rate of false-negative or even false-positive reactions. Very recently, possible alternatives have been described, which can be performed in routine laboratories without the need for expensive equipment. Streptavidin-Nanogold-Silver ISH is an easy-to-perform assay, which can be applied to detect low copy numbers of nucleic acid sequences in paraffin sections and cytological preparations. Its combination with labelled tyramides (TSATM = tyramide signal amplification, also known as CARD = catalysed reporter deposition) can achieve single gene copy sensitivity in detecting DNA viruses and also shows very high sensitivity for RNA detection. Possible applications include the early recognition of viral infection, cancer-associated genes, genetic diseases, and also the specific detection of mRNA.

Acetates↗
PubMed2003

Polymeric (O-ethyl dithiocarbonato)silver(I).

The title compound, [Ag(C(3)H(5)OS(2))](n), is polymeric in the solid state and adopts a layered structure in which each Ag atom is five-coordinated in a distorted trigonal-bipyramidal geometry defined by four S atoms belonging to four different xanthate groups and by a neigbouring Ag atom [Ag.Ag = 3.0540 (8) A]. Each S atom is three-coordinated to one C and two Ag atoms. The structure can be envisaged as being formed by Ag(2)(S(2)COEt)(2) units in which every S atom is bonded to another Ag atom from a different unit and the Ag atoms are also bonded to two different S atoms of two other units. The result is a two-dimensional network of condensed metallacycles of six or eight atoms.

Journal Article↗
PubMed2004

Bis(micro-4-chlorobenzoato-kappa(2)O:O)bis[(2-aminopyridine-kappaN)silver(I)].

The title compound, [Ag(2)(C(7)H(4)ClO(2))(2)(C(5)H(6)N(2))(2)], lies about an inversion centre and the Ag atom is three-coordinated by two O atoms and one N atom from three different ligands. The 4-chlorobenzoate anion acts as a monodonor ligand, bridging two inversion-related Ag atoms of the compound into a dimer. There are weak intermolecular N-H.O hydrogen bonds in the structure.

Journal Article↗