The present study was designed to measure the durability of glass fiber-reinforced hybrid resins (FRC) in clinical applications. Accordingly, we studied the effects of static and dynamic loading as well as temperature changes inside the oral cavity, a moist environment, on the bending strength of FRC. The bending strength was measured using several tests, including an open-air bending strength test (AE), a 24-h water immersion test (WC1D), a 2-year water immersion test (WC2Y), a thermal cycling test (TC), a repeated in-water impact test at 37°C/10(5) (WI37), and a repeated in-water impact test at 55°C/10(5) (WI55). The following tests are ordered from greatest to least with respect to GF's bending strength: AE, WI37, WI55, WC1D, WC2Y, and TC. Likewise, the following tests are ordered from greatest to least with respect to EV's bending strength: AE, WC1D, WC2Y, WI37, WI55, and TC.