Porcelain, highly esthetic, anterior maxilla area, we choose.. in ceram

Porcelain, highly esthetic, anterior maxilla area, we choose:

A- Dicor

B- in ceram. ***

C- impress

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In-Ceram has been used to fabricate fixed partial dentures, but the manufacturer recommends only short-span (three-unit) anterior restorations.

Alumina-reinforced ceramic systems (In-Ceram) significantly improve the light reflection characteristics of crowns when compared to conventional metal-ceramic restorations.

However, opaque aluminum oxide diminishes translucency when compared to leucite-reinforced systems (Optec, IPS-Empress). To improve light transmission and reflection in single anterior crowns where maximum strength is not required, a magnesium aluminous

spinel may be utilized. The transilluminating qualities seem to be similar to those of natural teeth.

Porcelain is a fine and translucent ceramic that, if it is produced from kaolin by baking at over 1,200 ° C, takes on the more precise name of hard porcelain. It is mostly used in the arts of the table.

The techniques of porcelain manufacture reached their perfection in China in the twelfth century, in Germany in the eighteenth century, and in France at Limoges in the nineteenth century.

The oldest Chinese porcelain seen in Europe is a 12 cm tall vase dating from the end of the 13th or beginning of the 14th century preserved in the treasure of St. Mark of Venice. It is called the Marco Polo vase, although it is not certain, nor indeed impossible, that it was brought back from China by one of the Polo.

After long scientific debates, the experts of the Chinese ceramics consider today that it is under the Eastern Han dynasty (between -206 and 220 AD) that appeared the first real porcelains. To arrive at this conclusion, they developed a set of criteria involving the firing temperature (1260 to 1300 ° C), the proportion of kaolin (30 to 60%), the iron oxide content. (less than 1.7%), the porosity rate (0.6%), the absorption rate (0.3%), the translucent appearance (up to 5 to 8 mm), or the resonance to shock.
The cooking process up to about 1200 ° C and vitrified white pottery using pasta mainly composed of kaolin have existed in China since the third century at least, although at that time the vast majority of ceramics were in fact simple pottery, or, at best, grèsN 2. This ancient discovery of porcelain was a technical triumph in the field of ceramics, although it was not until the seventeenth and eighteenth centuries to see pouring into Europe porcelain "egg shells" whose thinness of the walls highlighted the translucent character.

The earliest attempts by European potters to reproduce these Chinese porcelains date back to the seventeenth century, at a time when their composition was poorly understood and its constituent materials were not widely available in the West. The first formulations were mixtures of clay and crushed or sintered glass. Steatite or lime were also incorporated in some compositions. These first Western porcelains are called soft porcelains. Despite their technical imperfections, they participated in the development of English and French manufactures (Chelsea, Vincennes, Chantilly, Saint-Cloud ...). Soft porcelains are also commonly called English porcelain or French porcelain.

The processes were originally of a semi-artisanal nature. The pieces were made by workers distributed in more than a dozen categories: modelers, polishers, turners, molders, packers, packers and retouchers.
In the nineteenth century, the adoption of the technique of casting a fluid paste in molds made of plaster considerably simplifies the manufacture of parts. The first artifacts thus made sometimes present a defect: the suture of the left and right parts is visible by a small bead which has not been sufficiently flattened.

Today, the manufacturing starts with the modeling of pieces according to the needs of the chefs de cuisine. The concept is then worked to obtain a three-dimensional aesthetic piece that will be used for the manufacture of plaster molds from a hand carved matrix.

Porcelain does not come from natural clay. It is mainly composed of a mixture of quartz, feldspar and kaolin, added with ball clay to increase its plasticity. Quartz and feldspar are reduced to powder by the action of granite wheels, then ground in a rotating cylinder containing pebbles and water. Feldspar lowers the vitrification point of porcelain during cooking.

These three ingredients are mixed with water so as to obtain a more or less liquid paste adapted to the selected manufacturing process (pouring or sizing).