オールセラミッククラウンへの期待と現状 セラミックスの加圧成型によりクラウンを製作するシステムについて

Abstract

Since the 1980's, various kinds of all-ceramic crowns have been developed. These all-ceramic crowns have higher esthetics and biocompatibilities than conventional porcelain-fused to metal crowns. Among them, Empress (Ivoclar AG), a heat-pressed ceramic, is known as a material that can reproduce the color and light transmission of the natural tooth.Empress is a leucite reinforced ceramic made by heat-pressing of glass-ceramic ingot with the lost wax technique. Empress provides two kinds of techniques, layering technique and staining technique. If the esthetic consideration is the most important like anterior teeth, the layering technique is the method of choice by cutting the labial surface and building up with enamel porcelain. Advantages of Empress crowns are as follows: 1) esthetical appearance similar to natural teeth, 2) enough resistance to masticatory forces, 3) excellent fitness, 4) less irritation to gingiva and soft tissue, 5) sufficient radiolucency and 6) less solubility and sufficient durability.In clinical studies on Empress crowns, the sufficient success rate was registered when the adhesive technique was used. These results demonstrated that Empress could be reliably used to make single crowns.Recently, Empress 2 was developed to fabricate all-ceramic bridges. Empress 2 consists of the lithium disilicate framework ceramic and the apatite layering ceramic. As a result, the Empress system is useful in anterior bridges as well as crowns, inlays and veneers.