From body-on-frame to unibody constructions and designs mimicking biological structures - an overview.

In dentistry, isotropic materials, such as metals, ceramics, and polymers, are used. Their properties are not related to any specific direction of the material microstructure. There is a trend toward non-metallic, adhesive, and minimally invasive dentistry. This is in line with the conceptual change seen in the automobile industry, in which the basis of car structures has changed from body-on-frame designs to unibody designs. In unibody designs, all structural parts of the body of the car mechanically form a single structural entity. In modern adhesive dentistry, remaining tooth substance and the dental material form unibody designs, enabling preservation of tooth substance. Biological structures are created to withstand loading and are light in weight. The structural designs of elements in these biological materials are, to a large extent, based on fibrous material. More attention has been paid to mimicking fibrous structures of dental hard tissues by synthetic fiber-reinforced composites. This overview reports key features of natural fibrous elements and how they are utilized in dentistry. Special emphasis is placed on the aspects of interfacial adhesion of restorative materials, especially ceramics to resin-based materials and their role in the unibody design of the tooth-restoration system.