 This study investigated the effects of thermal cycling on two types of high-performance polymers used in CAD slash CAM milled frameworks for definitive restorations. The results showed that both materials met or exceeded the ISO standards for dental resins in terms of flexural strength. However, the flexural strength of the glass fiber reinforced composite, FRC, material decreased significantly after being exposed to thermal cycling. Therefore, it is recommended that these materials be used only for short-term applications such as single crowns and bridges. This article was authored by Hanine E.S. Lam.