Vicari CB, et al. - The experts undertook this study to assess the fatigue behavior of 2 crystalline-reinforced ceramics: Leucite-reinforced (VL) and lithium disilicate-based (VD) glass-ceramics. After a lifetime of 104 cycles, both glass-ceramics showed similar strength degradation (60%), notwithstanding their distinct mechanical properties. For the degradation of the mechanical properties of crystalline-reinforced glass-ceramics, mechanical cycling in humid conditions proved to be an important factor.