Book excerpt: Resin materials are broadly used in dentistry for almost all indications, and they will gain even more importance in the future. Especially the increasing performance and efficiency of the CAD/CAM technology and 3D-printing open possibilities to use resins which were not used up to now in dentistry. Besides dentists, dental students or dental technicians, there are many other specialists such as researchers, material scientists, industrial developers or experts of adjoining professional disciplines who are technically engaged in dental resins. The "Expert Level" is the third book of the series "Dental Resins - Material Science & Technology". The "Expert Level" includes all information and data presented in the "Basic Level" and "Advanced Level" of this series, but enormously expands the knowledge base. From a total database of 8.198 references, 1.707 were selected and used for this textbook. It comprises more than 1,000 manuscript pages, 384 figures and 124 tables. The "Expert Level" describes very accurately and comprehensively all details of the material science and technology of dental polymers and composites. Furthermore, their production methods and applications are discussed in detail. Therefore, this book is a unique treatise of the complete present knowledge about dental resins and dental resin composites. This includes the discussion of the - raw/starting materials together with the explanation and presentation of their chemical structures and properties, their CAS Numbers and the names of the manufacturers. - amounts of the raw/starting materials usually used to formulate the finished products. - important material and toxicological properties of the starting materials and the finished products. - detailed description of the production processes of essential starting materials such as the syntheses of essential monomers, the silanization of inorganic fillers or the manufacturing of unfilled and filled splinter polymers. - detailed description of the formulation and the properties of the finished products. Furthermore, for many commercial endproducts rather detailed formulations as well as the exact production processes are described. All ISO standards that are relevant for dental resins are listed, too. Furthermore, many essential methods to test the mechanical, chemical and toxicological properties are also presented and explained. The "Expert Level" enables every scientist with a good chemical knowledge not only to understand how dental polymers function, but also to develop new and improved products.