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| IPS Empress | |||||||||||
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Pressable ceramics have been around for about a decade. Empress was and still is, the leader in pressable ceramics. Ivoclair innovated the pressed ceramic crown. Before that, the laboratory had to fuss with problematic refractory dies and over sensitive porcelains. There were also problems chair side for the dentist and patient. Refractory fired all-porcelain crowns were prone to failure. At the time, the crowns were conventionally cemented, and without the metal sub-structure, the crown was just too weak to take chewing pressures. With the invention of pressables, the past problems of all-porcelain crowns seemed to disappear. Not only did the difficulty in fabrication end, but the strength issue was addressed and kicked in the rear. The Empress crown has a lithium disilicate core which gives it its strength. The layering porcelain boasts a wear rate that is equal to natural dentition. Esthetically, the IPS Empress restoration is the ideal choice to technicians worldwide, due to its opalescent properties which is key in achieving natural light transmissions that cannot be attained with conventional porcelain to metal crowns. When the All-Ceramic crown is bonded, not cemented, the strength of the crown is 95% of it's original tooth strength. By comparison, an amalgam filling that is involved on three surfaces is 35% as strong as the original tooth. Fabrication of the pressed ceramic crown is very similar to the cast crown outlined on our home page. A crown is waxed up on a removable die model, just like a cast crown. Then the crown is sprued and invested. Instead of casting the investment with centrifical force, the ring is placed in a special furnace that plunges a solid melted pellet of porcelain into the void in the ring. So what was once wax is now an all ceramic crown.
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