Adhesion as a component of retention force of overdenture prostheses-study on selected Au based dental materials used for telescopic crowns using atomic force microscopy and contact angle techniques.

Contemporary prosthetic materials are characterized by highly specific preparation for a given application. This means that at the stage of their creation, not only their function is taken into account, but also the long-term behavior of this material during use. In the case of telescopic crowns, an important factor not yet appearing in the research is the aspect of adhesion force and its dependence on the type of biomaterial, but also the properties of human saliva. The use of artificial saliva, which creates a lubricating layer, reduces the wear on the surface of the telescopic crowns by reducing friction. The impact of artificial saliva on the formation of chemical bonds between prosthetic elements, thus contributing to the so-called retention force has not yet been studied. In this work, two types of measurements of gold telescopic crown materials in the aspect of the adhesion process are presented. Obtained results allowed to fully characterize this phenomenon. We modeled the load force between the microcircuit and the surface under study to suit the conditions between the primary and secondary crowns in the patient's mouth.

Hierarchical approach for the rational construction of helix-containing nanofibrils using α,ß-peptides.

The rational design of novel self-assembled nanomaterials based on peptides remains a great challenge in modern chemistry. A hierarchical approach for the construction of nanofibrils based on α,ß-peptide foldamers is proposed. The incorporation of a helix-promoting trans-(1S,2S)-2-aminocyclopentanecarboxylic acid residue in the outer positions of the model coiled-coil peptide led to its increased conformational stability, which was established consistently by the results of CD, NMR and FT-IR spectroscopy. The designed oligomerization state in the solution of the studied peptides was confirmed using analytical ultracentrifugation. Moreover, the cyclopentane side chain allowed additional interactions between coiled-coil-like structures to direct the self-assembly process towards the formation of well-defined nanofibrils, as observed using AFM and TEM techniques.

Analysis of the electrolytically polished skeletal dentures surfaces using various nano- and microscopic technologies.

PURPOSE: The surface roughness of the dental restorations is significant to the denture plaque adhesion. METHODS: In this work, we present the complex analysis of the electropolished CoCrW alloy remanium® star (Dentaurum, Germany) samples with laserengraved fiducial marks performed using complementary set of micro- and nanoscopic techniques: optical profilometry (OP), atomic force microscopy (AFM), scanning electron microscopy (SEM) and focused ion beam (FIB) milling. RESULTS: Both mean and RMS roughness of the samples were reduced by electopolishing process, however, the results obtained using OP and AFM exhibited some discrepancies. This was caused by the relatively high local protruding defects developed on the processed surface. The cross-sections of the protrusions were made to analyze the cause of their formation as the EDS elemental content maps revealed that their composition was uniform. We also analyzed the local roughness in the smaller areas free from the defects. CONCLUSIONS: In that case, both OP and AFM techniques delivered the same results. Analysis of results showed that various methods used for the surface roughness evaluation have to be used simultaneously to obtain complete and true analysis of the technological CoCrW samples.

Optimal Design of Electromagnetically Actuated MEMS Cantilevers.

In this paper we present the numerical and experimental results of a design optimization of electromagnetic cantilevers. In particular, a cost-effective technique of evolutionary computing enabling the simultaneous minimization of multiple criteria is applied. A set of optimal solutions are subsequently fabricated and measured. The designed cantilevers are fabricated in arrays, which makes the comparison and measurements of the sensor properties reliable. The microfabrication process, based on the silicon on insulator (SOI) technology, is proposed in order to minimize parasitic phenomena and enable efficient electromagnetic actuation. Measurements on the fabricated prototypes assessed the proposed methodological approach.