712 research outputs found
DFT calculations and electrochemical studies on azulene ligands for heavy metal ions detection using chemically modified electrodes
A computational study on three related derivatives of 5-[(azulen-1-yl)methylene]-2-thioxoimidazolidin-4-one was conducted using density functional theory by calculating a series of molecular descriptors and properties of their optimized geometries (electrostatic and local ionization potentials, molecular frontier orbitals, etc.). Thermodynamic properties (zero-point energy, enthalpy, constant volume heat capacity, entropy and Gibbs energy) for these derivatives have been calculated and related to ligands electrochemical behavior. Reduction and oxidation potentials have been correlated to their calculated energy levels for LUMO and HOMO orbitals. Chemically modified electrodes based on these derivatives have been tested in view of heavy metal ions recognition, and their detection limits have been correlated to the calculated values of electron affinity
Advances in Dentures: Novel Polymeric Materials and Manufacturing Technologies
Acrylic resins dominated dentures technology for several decades. Due to their many disadvantages, new types of polymers, with better properties, suitable for dental prosthodontics applications were constantly attempted. The choice of polymeric materials and manufacturing technologies has experienced significant development in recent years. Different types of thermoplastic injected resins, light-cured resins, or the versatile high-performance polymers are several choices of novel materials for dentures manufacturing. CAD/CAM systems, both substractive and additive, are being considered the most promising choice for the future manufacturing of polymers in dentistry. The chapter is focused on presenting the choices of novel polymeric materials, their manufacturing technologies, and applications in prosthodontics
DFT calculations and electrochemical studies on azulene ligands for heavy metal ions detection using chemically modified electrodes
A computational study on three related derivatives of 5-[(azulen-1-yl)methylene]-2-thioxoimidazolidin-4-one was conducted using density functional theory by calculating a series of molecular descriptors and properties of their optimized geometries (electrostatic and local ionization potentials, molecular frontier orbitals, etc.). Thermodynamic properties (zero-point energy, enthalpy, constant volume heat capacity, entropy and Gibbs energy) for these derivatives have been calculated and related to ligands electrochemical behavior. Reduction and oxidation potentials have been correlated to their calculated energy levels for LUMO and HOMO orbitals. Chemically modified electrodes based on these derivatives have been tested in view of heavy metal ions recognition, and their detection limits have been correlated to the calculated values of electron affinity
Indirect Restorative Polymeric Dental Materials
The current chapter, entitled “Indirect restorative polymeric dental materials,” is dedicated to one class of dental materials with wide indications in dental medicine. The chapter is an overview of polymeric resin composites dedicated to indirect restauration currently used and latest avail resin composite and polymers in dentistry. This chapter includes chemical composition, indications, light-curing mechanism and physical and mechanical properties of indirect conventional and new polymeric materials. Important aspects about resin composites are related to clinical and physical properties such as light-curing, aesthetics, wear rates and biocompatibility. The accuracy and longevity of indirect composite restorations depend on choosing the right material according to clinical requirements, material’s properties, and behaviour in the oral cavity and clinical indications. The chemical composition of resin composite, curing mechanism and advantages of these materials are presented in Introduction. The second section is dedicated to structure and composition of indirect polymers, indirect resin composites, first and second generation of indirect resin composites and their indications. Section 3 describes the structure and composition of high-performance hybrid polymers, hybrid ceramic and high-performance polymers, and poly ether ketone ketone dedicated to different processing technologies
Dental Anatomy and Morphology of Permanent Teeth
The present chapter is proposing a detailed and illustrated description of dental morphology of permanent dentition. The main topics are related to nomenclature, age of emergence, a description of teeth’s tissues (pulp, dentin, enamel, and cement), and morphology of all permanent teeth. The main focus of this chapter is the description of individualized morphology and specific variations of each permanent tooth. The goal of all treatment phases in dental medicine is to restore the function, integrity, and morphology of the oral cavity, and all these achievements are reached through deep knowledge of dental morphology. Cavities are restored with direct dental materials, which need to be carved according to the natural shape, outlines, occlusal and proximal contacts of teeth’s morphology, reproducing also the shade and translucencies of natural teeth. The same goal dominates the prosthodontic field. It is well known in dental medicine that shape, size, and position assure the optimal function and preserve the self-maintenance of dental arches and dento-maxillary system. For esthetic, function, and self-preservation, all dental treatment fields have to first consider the dental morphology
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