SUMMARY OF KNOWLEDGE ABOUT 3D PRINTING AND ITS USE IN DENTISTRY

Introduction, aim: The rise of research papers and investments made into 3D printing are the proof of the increased interest about this manufacturing method. The American Charles W. Hull is considered to be the inventor with the first patent in the field. The principle of 3D printing is printing the desired item in layers according to its template, most often present in .stl format. There are seven main technological processes of 3D printing, five of them are used in dentistry. Text deals with the three methods that are used the most: Vat Polymerisation, Material Extrusion and Powder Bed Fusion. In dentistry, additive manufacturing already has an important role for a longer period of time especially in implantology for the printing of surgical guides and in orthodontics for printing of study models and so-called invisible aligners. Additive manufacturing also allows to print retention appliances, and it facilitates the autotransplantation of teeth, while its importance is slowly rising in other sectors of dentistry such as in conservative dentistry in Class IV reconstruction or in guided endodontics and in prosthetic dentistry for printing of metal substructures and other components either in fixed or removable prosthetics in dental laboratory. Printing of accessories such as protective masks and face-shields or printing of 3D models of the real teeth and demonstration models in order to improve undergraduate, postgraduate and continuous education are among current applications. In medicine the printing is used for example for the production of biomaterials. The range of applications is therefore vast and the impact of 3D printing on dentistry is unquestionable. Shortcomings of printing are undergoing constant research and therefore it is just a matter of time until 3D printing will replace the conventional methods. The objective of this review paper was to sort the basic information about 3D printing with regards to its history, principle and types of printing but more importantly to summarise its use in dentistry

Pulsed Nd:YAG deposition of nanostructured FeS1-x containing meta-stable phases

Pulzní laserové ozáření sulfidu železitého (FeS) v blízko-IČ oblasti záření ve vakuu umožňuje nekonguerentní ablaci a depozici nanostrukturovaných tenkých vrstev FeS1-x. Depozice byla provedena na nezahřátý substrátu Al, Ta a Cu a tenké filmy byly analyzovány se skenovací (SEM) a transmisní elektronovou mikroskopií (HRTEM) s vysokým rozlišením a elektronovou difrakcí. Morfologicky podobná homogenní, tmavá, kovově vyhlížející adhesní vrstva byla detekována pro všechny depozity (SEM). Při použití HRTEM v souladu s elektronovou difrakcí však bylo zjištěno rozdílné fázové složení na různých substrátech. Na substrátu Ta byla detekována kubická fáze pyritu (FeS2). Kubický pyrit (FeS2) a metastabilní rhomboedrický smytite Fe9S11 byly nalezeny v případě Al substrátu. Kubický pyrit (FeS2), metastabilní rhomboedrický smythite Fe9S11 a metastabilní orthorombický markasit (FeS2m) odhalila HRTEM analýza filmu na Cu substrátu. V případě všech depozitů byla detekovány krystalická nanozrna obklopená amorfní matricí.Pulsed near-IR laser irradiation of ferrous sulfide (FeS) in a vacuum allows a noncongruent ablation and deposition of nanostructured FeS1-x thin films. Deposition has been performed on Al, Ta and Cu unheated substrate and analyzed by scanning (SEM) and high resolution transmission electron microscopy (HRTEM) and electron diffraction. Morphologically, the similar homogeneous, dark, metallic and adhesive appearanceshave been revealed for all the coats deposited on various substrates (by SEM). However, using HRTEM in agreement with electron diffraction, different phase composition on various substrates has been detected. Cubic pyrite phase (FeS2) has been detected on Ta substrate. Cubic pyrite (FeS2) and metastable rhomboedric smythite Fe9S11 have been found in case of Al substrate. Cubic pyrite (FeS2), metastable rhomboedric smythite Fe9S11 and metastable orthorhombic marcasite (FeS2m) revealed HRTEM analysis of the film on Cu substrate. In case of all deposits the detected crystalline nanograins were surrounded by amorphous matrix