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Examined Materials (examined + material)
Selected AbstractsThe effect of home-use fluoride gels on glass,ionomer, compomer and composite resin restorationsJOURNAL OF ORAL REHABILITATION, Issue 7 2003P. Dionysopoulos summary The purpose of this study was to investigate the resistance to dissolution by two home-use fluoride gels on the surface integrity of glass,ionomer, resin modified glass,ionomer, compomer and composite resin restorations. Class V cavities prepared in extracted teeth were restored with a glass,ionomer (Fuji II), a resin modified glass,ionomer (Vitremenr), two compomers (Dyract and F-2000) and a composite resin (Z-100). Groups of five specimens of each material were treated for 24 h with one of the following: (i) distilled water, (ii) neutral fluoride gel and (iii) acidulated phosphate fluoride (APF) gel. Surface degradation of the restorations was studied using standard electron microscopy (SEM), rated according to specific criteria and statistically analysed by the Wilcoxon test (rank sums). Acidulated phosphate fluoride was found to have a significant effect on all examined materials, while minimal effects resulted from the neutral fluoride gel compared with the control group. The effect of home-use fluoride gels on glass,ionomer, compomer and composite resin restorations. [source] Laboratory strength of glass ionomer and zinc phosphate cementsJOURNAL OF PROSTHODONTICS, Issue 3 2001Andree Piwowarczyk Dr med dent Purpose The present in vitro study examined 3 mechanical properties, namely compressive, flexural, and diametral tensile strength, of various commercially available cements and core materials as a function of time after mixing. Materials and Methods The examined materials were 2 cermet cements (Ketac Silver [ESPE, Seefeld, Germany] and Chelon Silver [ESPE]), 1 metal-reinforced glass ionomer cement (Miracle Mix [GC Dental Industrial Corp, Tokyo, Japan]), 2 conventional glass ionomer cements (Ketac Bond [ESPE] and Ketac Cem [ESPE]), 1 standard cure zinc phosphate cement (Harvard Cement [Richter and Hoffmann, Berlin, Germany]), and 1 zinc phosphate cement with the addition of 30% silver amalgam alloy powder (Harvard Cement 70% with Dispersalloy 30% [Richter and Hoffmann/Johnson and Johnson, East Windsor, NJ]). Properties were measured using a universal testing machine at 15 minutes, 1 hour, and 24 hours after first mixing. Results Compressive strengths varied widely between the 3 times of measurement from 5.8 ± 6.6 MPa for Ketac Cem to 144.3 ± 10.2 MPa for Ketac Silver. Twenty-four hours after mixing, the Bonferroni test showed significant (p, .01) differences between Ketac Silver and all other materials tested. Diametral tensile strengths ranged widely from 4.4 ± 0.9 MPa for Ketac Cem to 11.5 ± 2.2 MPa for Chelon Silver. At 15 minutes, 1 hour, and 24 hours after first mixing, the analysis of variance did not show any significant differences between Ketac Silver, Chelon Silver, and Miracle Mix. The 3-point flexural strength of Ketac Silver showed, at 15 minutes with 13.5 ± 3.9 MPa and at 24 hours with 27.2 ± 7.4 MPa, the highest values. Conclusions Setting time influences the mechanical properties of the materials tested in this study. Ketac Silver, a glass ionomer cement reinforced with sintered glass-silver particles, showed the highest mechanical properties of the examined materials. [source] Metallic dental materials in patient's oral cavity acting as electrodes of electrochemical cellsMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 7 2004W. Opydo Abstract The work was aimed at studying of standard potentials of commonly used metallic dental materials and determining of the effect of saliva conductivity and reaction on value of the potentials. The following materials have been examined: gold alloy (a material used for crowns and bridgeworks), chromium-cobalt alloy (for frameworks in removable partial dentures), and silver amalgams (used for fillings) manufactured by three different companies. Taking into account that mucosa makes one of the electrodes existing in oral cavity the rest potentials of mucosa have been in vivo measured in several patients. Their values, converted with respect to NHE, oscillated within the range from + 0.31 V to + 0.47 V. Among metallic dental materials examined in the experiment maximal standard potential was found for the gold alloy, further materials having lower potentials, in decreasing order, were chromium-cobalt alloy, and the amalgams Amalcap Plus, ANA 2000 and Septalloy. Significant differences between standard potentials of examined materials and mucosa indicate spontaneous formation of galvanic cells of electromotive force reaching even about 0.6 V. [source] Influence of alloying elements on the structure and corrosion resistance of galvanized coatingsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2004G. Vourlias Abstract Carbon steel samples were galvanized by the hot-dip method in zinc baths containing 0.5 or 1 wt% aluminum, copper, tin, nickel, and/or lead. Bath temperature ranged from 450 to 480 °C. The samples were examined using optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The influence of the alloying elements on the formation of the different phases and on the diffusion process is discussed. In order to study the kinetics and the mechanism of corrosion of these materials, corrosion experiments were carried out in a simulated environment of accelerated atmospheric corrosion conditions, for which a special chamber (Salt Spray Chamber , Alternative Climate Test Chamber) of type SC-450 was used. The corroded samples were examined using optical microscopy, SEM and XRD. Chloride and oxide phases, which penetrated the materials to different depths from the surface, were revealed. Finally, useful conclusions were drawn which help to control the factors of the corrosion behavior of the examined materials in a marine atmosphere. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The Morphology of the Cervico-thoracic Sympathetic System in Donkeys (Equus asinus L.)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2 2009O. Ozgel Summary Five adult donkeys of both sexes, used in applied anatomy classes, and perfused with formalin for teaching purposes, constituted the study material. Ganglion cervicale caudale of the examined materials has observed to exhibit individually variable situation as to extend on the left side of the median line, at the alignment of the first and second intercostal spaces and on the right side between the level of the first and third costa. The ganglion extended more caudally on the right side of median line. The lateral surface of the ganglion was determined to be covered with the m. scalenus medius. On the both sides of the median plane, the ganglion cervicale caudale was seen to be situated on the lateral surface of the m. longus colli. On the left side, the ganglion overlapped the oesophagus in two cadavers and on the right side it was situated within a groove between the m. longus colli and trachea in three cadavers. The rami communicantes received by the ganglion cervicale caudale originated from the eighth cervical and first thoracic spinal segments. The ganglion cervicale caudale was formed by the coalescence of the last cervical and first three thoracic sympathetic ganglia. The ganglion cervicale caudale gave off branches that formed the rami communicantes, plexus cardiacus, n. vertebralis and ansa subclavia. One branch extended from the ganglion to the plexus brachialis. in one specimen, two sympathetic,parasympathetic communicating branches were observed to extend from the ansa subclavia and near by the origin of the truncus sympathicus to the n. vagus. In one of the donkeys examined, a branch originating from the ganglion cervicale caudale on the left side of the median plane was determined to end on the ligamentum arteriosum. A microscopic ganglion structure suggesting the existence of the ganglion cervicale medium was determined in a donkey. [source] | ||||||||||