Figure 7.
Bite force to penetrate layer thickness versus number of cycles for flat layer structures of net thickness 1.5 mm bonded to dentin and loaded axially with a porcelain sphere (or opposing tooth) of radius 5 mm. Trendlines evaluated from fracture mechanics lifetime equations, in conjunction with data extrapolation from Fig. 6.118 Estimates for (a) lithium disilicate and (b) zirconia cores veneered with 1 mm porcelain, and (c) lithium disilicate and (d) zirconia monoliths. Trendlines can shift according to key material and geometrical conditions.