Effect of ion-exchange treatment on mechanical properties of new dental ceramics

Purpose: To examine whether the ion exchange strengthening can be achieved for several new ceramics such as glass ceramics or castable ceramics. Methods: The ceramics selected for this study were three porcelains and three castable ceramics. 60 bend bars of the respective ceramics (1 x 5 x 10 mm) were fabricated according to the respective manufacturer's directions. Finally, the respective specimens were polished up to 0.1 mum and then divided into two groups: one was coated with an ion-exchange paste and the other was not treated as the control. Then, for the respective ceramics the hardness, flexural strength and fracture toughness were investigated and compared to the control. Results: Although the ion-exchange treatment significantly (P< 0.05, Scheffe's test) increased flexural strength and fracture toughness for the porcelain based ceramics, it did not increase these properties for the castable ceramics. The chemical treatment did not affect hardness for any of the specimens.