Future perspectives of biomaterials for dental restoration

摘要

The development of biomaterials that can be used to substitute metals in dental restorations represents the main challenge of future research activities until the year 2020. Therefore, the authors will focus on the presentation of two types of biomaterials for dental restoration: glass-ceramics and sintered ceramics. Dental biomaterials must have a highly aesthetic appearance that is comparable to that of natural teeth. Furthermore, they must be more durable than natural teeth and show good mechanical properties at ambient temperatures. Based on the state of the art and the latest research activities, the presentation is focused on glass-ceramics with high toughness, glass-ceramics with optical properties comparable to those of natural teeth and glass-ceramics that are processed with preferred techniques, for example, those which are moulded on different types of high-strength substrate materials. In addition, high-strength and high-toughness materials such as lithium disilicate glass-ceramics can be processed either by moulding or by a new method, that is, machining. Possible directions will be presented for moulding different types of glass-ceramics such as fluoroapatite containing glass-ceramics on high-toughness substrates made of glass-ceramics or very tough sintered ceramics. The focal point of this presentation is the demonstration of the high-strength and high-toughness sintered ceramics of the ZrO_2 type. The preferred processing method of this type of biomaterials for dental restoration is machining using CAD/CAM technologies. Future activities will be focused on improving the quality of the ZrO_2-type biomaterial. At present ZrO_2 ceramics are white opaque. One of the main aims is to achieve optical properties comparable to those of natural teeth in ZrO_2 ceramic. Therefore, the material has to be developed in special dental colours with the same mechanical properties and good durability as that of the white ZrO_2. The authors will show future directions for developing coloured ZrO_2 sintered ceramics. Future research activities will be focused on gaining a better understanding of the phenomena and mechanisms of toughening glass-ceramics and ceramics. With the acquired knowledge on the toughening mechanisms, new directions for developing ceramics until the year 2020 will be explored. The technology to achieve this goal will be applied nanotechnology.