Search results for "Cavity wall"
showing 6 items of 6 documents
Advanced Techniques of Micro-Analysis and Confocal Microscopy: Perspectives for Studying Chemical and Structural Changes at the Interface Between Res…
1995
Migration of trace amounts of elements and structural changes characterize the interface between immiscible substances. The contact zone among filling materials, saliva, and the cavity wall has the additional function of preventing the progress of leakage and subsequent caries. Difficulties in chemically and structurally analyzing the gradients of composition in an interface of microscopic dimensions characterize the experimental situation. The use of advanced techniques of instrumental micro-analysis and techniques of micro-visualization is our approach to the problem. With confocal laser scanning microscopy (CLSM), effects of the components of the filling material on the structure of the…
Vacuum energy densities of a field in a cavity with a mobile boundary
2015
We consider the zero-point field fluctuations, and the related field energy densities, inside a one-dimensional and a three-dimensional cavity with a mobile wall. The mechanical degrees of freedom of the mobile wall are described quantum mechanically and they are fully included in the overall system dynamics. In this optomechanical system, the field and the wall can interact with each other through the radiation pressure on the wall, given by the photons inside the cavity or even by vacuum fluctuations. We consider two cases: the one-dimensional electromagnetic field and the three-dimensional scalar field, and use the Green's functions formalism, which allows extension of the results obtain…
Field Fluctuations in a One-Dimensional Cavity with a Mobile Wall
2013
We consider a scalar field in a one-dimensional cavity with a mobile wall. The wall is assumed bounded by a harmonic potential and its mechanical degrees of freedom are treated quantum mechanically. The possible motion of the wall makes the cavity length variable, and yields a wall-field interaction and an effective interaction among the modes of the cavity. We consider the ground state of the coupled system and calculate the average number of virtual excitations of the cavity modes induced by the wall-field interaction, as well as the average value of the field energy density. We compare our results with analogous quantities for a cavity with fixed walls, and show a correction to the Casim…
Computational Study on Cesium Azide Trapped in a Cyclopeptidic Tubular Structure
2008
The structures and the electronic properties of host-guest complexes formed by a cyclopeptidic tubular aggregate and the species CsN3, CS2(N-3)(2), and CS2N6 have been investigated by means of density functional theory. Taking advantage of the azide property to act as a bridge ligand between two or more metal cations, it may be possible to trap N-3(-) ions inside a confined space. This could be important for the preparation of polynitrogen molecules N-n. Results show that there are significant attractive interactions between the azide ion and the cavity walls, which make the ion stay inside the inner empty space of the cyclopeptidic aggregate. The confinement of the species CS2(N-3)(2) forc…
Effect of cavity preparation instruments (oscillating or rotating) on the composite-dentin interface in primary teeth.
2003
Abstract Objectives: To evaluate the effect of preparation of instruments on the interfacial integrity between cavity wall and composite restoration. Methods: Two class II slot preparations were done in 10 primary teeth either with SonicSys® or with a conventional bur. The cavities were filled using an adhesive system. One layer of a flowable composite and one layer of a condensable composite were applied. The specimens were analyzed by confocal laser scanning microscopy. Results: In the SonicSys® group the mean thickness of the hybrid layer was 6.12 (0.60) μm; in the control group it was 6.04 (0.63) μm. The difference was not statistically significant. Two fractures were observed in one to…
Influence of cavity preparation technique (rotary vs. ultrasonic) on microleakage and marginal fit of six end-root filling materials
2010
Objectives: To evaluate in vitro the effect of cavity preparation with microburs and diamond-coated ultrasonic tips on the microleakage and marginal fit of six end-root filling materials. Study Design. The following materials were assessed: amalgam (Amalcap), zinc oxide eugenol (IRM), glass ionomer (Vitrebond), compomer (Cavalite), mineral particle aggregate (MTA) and composite (Clearfil). Cavity preparation was performed with microburs or diamond ultrasonic tips in single-root teeth. The seal was evaluated in two experiments: a microleakage assay on the passage of dye to the interface; and a scanning electron microscopy study and analysis of epoxy resin replicas, measuring the size of gaps…