FIGURE 1.

Differences between fracture resistance and load capacity. Fracture resistance is a mechanical property of a material in relation to the propagation of a pre‐existing crack. Different from fracture resistance, the load capacity is the maximum static load that a structure can sustain; it is affected by geometry and constituent materials. The testing of materials is different from the testing of structures composed of different elements. The former uses specimens of simple shapes under simple stress states. The use of cyclic fatigue data (a, D = dentine), stress versus life (N), can allow the investigator to make predictions for structures using stress analysis based on the physiological chewing force values (C). The use of static loading alone is not predictive; knowing the load capacity is not enough to predict the service life (number of cycles) of a structure because two structures can have the same load capacity but different service lives under simulated clinical conditions (b; M = molar, RM = restored molar). See how static loading (arrow) give information of only one cycle