Titanium

Introduction: - titanium is very good biocompatible material - it has a exeptional resistance before corrosion - it can be as a bioactive material, which can make adhesion to the vital tissue - even though it was applyed in dental practice as a last metal material

Introduction – titanium and its alloys: - in the nature is titanium as binary alloys, as a oxid TiO 2 - it discovered in 1789 in department of Cornwallu - at 1795 y. Mr. Klaproth detected, that it isi oxid unknown origin and he termed as a titanium - the rich europen deposits of titanium are in the Norway, Finland and in Russia - at 1822y. – was first isolated pure titanium, but in very little rate. It was enough for laboratory research. - at 1910y. – at first was isolated a lot of pure titanium Mr. Hunter, it was reaction between TiO2 and natrium

Introduction – titanium and its alloys: - at 1932y. – it was begin of industrial production of titanium ( chemical reaction between TiO2 and calcium) - from this metal it maked wires, plates and zo získaného kovu sa sformovali tyče, drôty a plech - other technology used for industrial production, chemical reaction between TiO2 and magnesium - with this technology was made a lot of tons of pure titanium. It was in America, Japan and in Russia.

Chemickal characteristic: - Titanium is alotropic metal (as a solid state has in two phases with unequal atomic lattice) - from the temperature 882°C is as a Atomic lattice, which is not so stable, as a cubic atomic lattice - if the temperature is less than 882°C, titanium has cubic atomic lattice - for practice it means, that by the temperature diverse between cooling and melting create changes between these two internal structure - by the very quick cooling, the number of atoms is decreased and it results to the depression of mechanical resistance

Chemical properties – pure titanium: - this metal has a strong potential to release the hydrogen - it results to the: - volume expansion of titanium maximally about 15 % - titanium obtained light color - metalic brightnees

Chemical charakteristic – pure titanium: - the atoms of oxygen and nitrogen can very quick to diffuse into the atomic lattice and so incresed melting temperature - it means, that by heating create: - oxidation on surface layer - dissolution of oxygen and nitrogen in metal - the very hard and think layer on surface, which is protection of titanium before oxidation. This layer must be remove before processing - others elements, as a niob, tantal, alluminium, tin and zircon change the mechanical properties by the changes into the atomic lattice

Physical properties: - titanium is the metal steel color with high brightness - difference from steel is in the weight. It is result from unequal density - the density of pure titanium is about 4,51 g/cm 3, and Ti – alloys is 4,40 – 4,80 g/cm 3. - in equation with cobalt alloys, which have density about 8,2 g/cm 3, the weight of the metal titanium cast is less about 43% than weight of similar cobalt cast ( according to large and shape) - titanium has worse termic conduction than cobalt alloys titán

Mechanical properties: - the mechanical properties is good, but titanium is more breakable than cobalt alloys, it has narrower flexibility - for the modification of mechanical properties is added to the titanium others elements, as a oxygen and ferrrum - according to content of oxygen and ferumm, can be the titanium alloys divided at four group( T1- T4)( similar distribution as a gold alloys) ; from soft to hard alloys

Corrosion of titanium: - pure titanium is very resistant metal - pure titanium can be enough stable in water and acid solution, - it is resistant to action of sulphur compounds - but fluoride compounds can change the surface of titanium and so support corrosion - similar effect have fluoride toothpaste with high content of fluoride ( more than 2000 ppm. They are the pastes for caries prevention, as Elmex gel, fluid or others solution for tooth protect before caries) - fluorides from solutions remove the passive layer from surface and so enable the absorbtion hydrogen and so participate on oxidatation and corrosion surface layer of titanium

Melting of titanium: - the melting of titanium is by the mercury arc in vacuum - intense cooling creates strong crust on the inside surface of special box - this crust can isolate melting titanium from the elements of box - this metod names as a „skull melting“.

Melting of titanium: - other type of melting titanium is during the induction current, the melting titanium is absorbed by the special ceramic box, which is indifferent according to composition of ceramic box - the ceramic crucible is to expensive and it can be used only once kelímok je však drahý a vhodný len na jedno použitie - this melting is in the vacuum with special inert gas, argon (colorless and odorless gas) - cooling of melting titanium is in vacuum too

Soldering: - soldering of titanium parts is by the welding - according to very strong chemical reaction of titanium by the temperature above than 500°C, must be soldering very quick and with high thermal energy - this condition satisfy the mercury arc, plasma, laser ray and electron stream - laser ray is the best for soldering of titanium parts - laser is device which can generate the monochromatic ray with high density of electrons and from it result the high thermic energy - it can function continuously

Soldering: -other type of soldering is by the solders - for soldering of titanium parts can be used the solders on argentum or palladium base - the cooling of soldering place must be during the protect atmosphere, in vacuum - the soldering space is the site with reduced resistence before corrosion

Biocompatibility: - titanium can be good biocompatible metal and bioactive metal - as a bioactive metal is participate the ions OH-, which can react with macromolecules of vital tissue and so produce biofilm - biocompatibility is compared with biocompatibility of gold alloys, although the titanium belong to the general metal alloys - it can make the active connection with vital tissue - although the price of pure titanium is narrower than the price of gold alloys, the technology of producing titanium is very expensive

Biocompatibility: - the resistance before corrosion is very strong, according to good passive layer - for elimination of cytotoxic elements is enough few milliseconds and the thickness of passive layer is only few nanometers - titanium in dental practice was begin use at 60-y. of 20.century - it was good reconstruction for very mechanical shirt sleeved, it was for implants of large joints - in equation with cobalt alloys the titanium alloys have better resistnace before corrosion, better biocompatibility and active bioadhesion

Conclusion: - in dental practice is used the titanium as pure metal - from titanium are made implants, crowns, metal construction for fixed bridge, metal framwork for sceletal RPD, clasps system and so on in combination with ceramic, have to be use the special type of ceramic ( it is zircon oxid ceramic, aluminium oxide ), because these types of ceramics are indiferent to the titanium and dont make the changes in atomic structure - the titanium is distribute from name as a Tritan, Rematitan ( as 6g rollers)

Pre prax:

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