Two types of these ceramics are CEREC Blocs (Sirona Dental Systems) and IPS Empress CAD (Ivoclar Vivadent) glass ceramics blocks. The ceramic restorations can be milled from prefabricated blocks with a CAD/CAM system. Chair-side production of restorations eliminates the need for interim restorations and decrease the risk of tooth structure fracture. Continual development of the hardware and software have expanded the restorative capabilities significantly. These systems provide design and automatic production of all-ceramic monolithic restorations in one appointment. Chair-side CAD/CAM systems can be used for fabricating ceramic inlays, onlays, veneers, crowns, and fixed dental prostheses. The innovations in digital optical impression techniques, virtual design software and precise milling machines, are rapidly improving fabrication methods. The computer-aided design/computer-aided manufacturing (CAD/CAM) technology has had a significant effect on both dental laboratories and clinics. Ceramic-resin bonding is successfully achieved through pretreatment of silica-based ceramics with acid etching followed by silanization. Īdditionally, resin cements can seal small cracks of the intaglio surface of ceramic restorations and improve ceramic strength. This bonding can increase the strength of ceramic which results in reduced fracture rate and increased lifetime of ceramic restorations.
Bonding with resin luting agents provides a chemical bond between the cement and the tooth as well as cement and the silanized glass. With the development and improvement of reliable adhesive bonding techniques, minimally invasive dentistry has become a field of great interest. This permits retaining more enamel and dentin and can provide better periodontal health by preservation of sound tooth structure.
Preserving tooth structure is critical for the longevity of teeth and restorations. While full coverage complete crown restoration requires substantial reduction of tooth structure, partial coverage preparations with reduced macroretentive geometry, such as inlays and partial coverage ceramic crowns have been reported to remove half the amount of tooth structure compared to a complete coverage metal ceramic crown. The use of ceramic restorative materials has increased significantly in the last decade due to increasing demands for esthetic and metal-free restorations.
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