5. Ranking of Dental Materials and Orthopedic Constructions by Their Tendency to Fracture

In modern orthopedic dentistry, three types of restorative materials are used: ceramics, metals, polymers. Metals which possess high strength and rigidity are used to ensure the ability of denture to bear significant mechanical loads. Instead, ceramics and polymers have become widespread. Combinations of different chemical materials are often practiced, as none of them alone can be considered the perfect. When choosing the appropriate material for orthopedic restorations, it is necessary to have complete information about its strength. The last one can change under the influence of various factors (defects of material in critical areas; state of the restoration surface; increased loads on the construction, etc.). For effective clinical use of certain materials, it is necessary not only to consider their mechanical properties, but also to know the dynamics of fracture processes. Such information can be obtained by using in mechanical tests the AE method with signal processing by WT. This chapter considers the mechanical characteristics and peculiarities of fracture of dental polymers, ceramics, and composites; the express technique of their ranking by the energy criterion of identification of the fracture types is constructed, and the peculiarities of fracture of the tooth-endocrown system under quasi-static compression are investigated.