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Zirconia: A Bit Of History And Its Applications In Dentistry

The zirconium or zirconia (the Arabic “zargun” which means “gold”), in its purest form exists in two forms: the crystalline form, a soft metal, white, ductile, and the amorphous form, a powder-blue black.

It is one of the most abundant elements, ranks 18 in abundance among elements in Earth’s crust, is very reactive chemically and is just combined. In most reactions with oxygen is bound in preference to other elements found in Earth’s crust just as the oxide ZrO2, Baddeleyite, or as part of the complex oxide, such as zircon, the elpidita, the eudialita, etc. .
Yet of the nearly 20 minerals containing zirconium, only two are of commercial importance:

Zircon. A zirconium silicate, is the primary source of supply

Baddeleyite. A zirconium oxide is a minor source of supply

These two minerals are mixtures of zirconium and hafnium which are virtually indistinguishable in their chemical properties, and were only found together.

Physical properties:

Zirconium is a grayish white metal, shiny, very resistant to corrosion and is lighter than steel. When finely divided can burn spontaneously in air (prior to nitrogen react with oxygen), especially at high temperatures (around 500 ° C). It is a metal resistant to acids, but can be dissolved with hydrofluoric acid.

The zirconium melts near 2715 ° C. It is estimated that its boiling point to 4377 ° C, but some observations suggest that it is near the 8600 ° C.

Collection:

The zirconium is not found in nature as free metal, but part of many minerals. The main source of zirconium is obtained from the mineral zircon, found in deposits in Australia, Brazil, India, Russia and the United States. It is also found in other minerals as Baddeleyite.

History of zirconium:

The element was discovered in 1789 by German chemist Martin Heinrich Klaproth and isolated as a metal by the Swedish chemist Jöns Jakob Berzelius in 1824.

In the late sixties started a study as a biomaterial called tetragonal zirconia polycrystal (TZP). Their properties were ideal for the preparation of spherical heads of hip prostheses.

Because of its high melting point and low thermal expansion, zirconium dioxide was also used to wrap nuclear fuel elements.

In 1975 the British physicist Ron Garvie published in renowned business journal Nature his striking work under the title ‘Zirconia: Ceramic Stell’ (zirconia, ceramic steel “?). His research on the possibility of stabilizing the tetragonal structure of zirconium dioxide by adding about 5.5% yttrium oxide material helped to achieve the exceptional mechanical properties and high biological stability.

The resistance to bending, the shear strength and modulus E reached values of steel, therefore, the ceramic Garvie also called ‘ceramic steel’.

A few years ago entered the field of dentistry for the performance of ceramic copings for crowns.

The zirconia is considered one of the best ceramic products on the market for dental reconstructions, from the 90s, it is increasingly used in the field of dental technology. It is estimated that between 15,000 and 20,000 zirconia structures are made each day worldwide.

Numerous tests have confirmed that a successful zirconia bridge is sufficiently strong even after 50 years. Studies have shown that zirconia does not produce any kind of contact allergy to the soft tissues in humans.

Zirconium is used in dentistry is zirconium oxide (zirconium dioxide), which when stabilized with yttrium generates an extremely hard ceramic material.

Possibilities of the zirconium oxide to the clinician:

The zirconium for their properties, hardness and biocompatibility, gives you the option of working in dental surgeries nonmetallic tools (cutters zirconium) to avoid any metal contamination that may be caused.

Furthermore, the rotary instruments made of zirconium oxide has advantages in dentoalveolar surgery in terms of temperature control and in economic terms can be reused a number of times and show no alterations or wear on its cutting blades.

The biggest advantage given to zirconium is that the dentist has the option of placing an implant of zirconium oxide rather than a metal one. The zirconium oxide implants are more stable from a mechanical point of view, besides that have opened the possibility of a new generation of color dental implants.

The most common application of zirconia is to develop dental veneers, crowns, inlays, though today prosthesis can be made of 14 pieces.

Due to its high biocompatibility, strength and esthetics it is today the best option to perform oral rehabilitations.

Jack Clarke has been an author and content publisher for the past 15 years. He currently runs several review sites including Jansport Book Bags among many others.

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About the Author:
Web publisher and author for the past 15+ years.
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