Press ceramics

In dentistry and dental technology, press ceramic is a process for the manufacture of all-ceramic crowns and bridges . For this purpose, a tooth-colored ceramic block , which is available in different tooth colors, is transformed by pressure and heat and pressed into a pressure and heat-resistant hollow shape. For this purpose, the crown is modeled in wax in the same way as the casting process and then manufactured using the lost wax process.

Manufacturing

Color sample scale for prosthetic reconstructions

Compared to the production of a metal casting (for example a gold crown), a special investment material is required. In addition, an extended burnout phase for the wax is required. The muffle and the ceramic blank are slowly heated to approx. 1200 ° C in a special oven . Then the muffle is placed in the press furnace at a temperature of approx. 1150 ° C. The selected ceramic blanks are placed in the upper chamber and pressed into the hollow mold under a pressure of approx. 0.4 MPa . The ceramic blank consists of a leucite-reinforced feldspar ceramic . The proportion of leucite crystals is 40–50%.

Further processing

Application of ceramic materials during the manufacture of ceramic restorations

Two techniques can be used to fabricate the final restoration to achieve an aesthetically pleasing result. A tooth contains different shades of color that are intended to be mimicked to achieve a natural look. Either the pressed workpiece is already produced in its final form in order to then be painted with ceramic paints. The disadvantage here is that the thin layers of paint can be removed again by abrasion . Alternatively, only the basic framework in the form of a cap made of press ceramic can be pressed. Then further ceramic layers in the necessary color shades are burned onto the coping in order to obtain the final shape and color of the tooth. The advantage is that the press ceramic does not experience any change in volume during the additional ceramic firings, so that the accuracy of fit is maintained.

Individual evidence

1. ↑ Bernard Touati, Paul Miara, Dan Nathanson: Aesthetic dentistry and ceramic restoration . Elsevier, Urban & FischerVerlag, 2001, ISBN 978-3-437-05100-5 , pp. 32-35.
2. ↑ Almut Rech: All-ceramic . Verlag Neuer Merkur GmbH, 2002, ISBN 978-3-929360-63-9 , pp. 107-111.

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