Effect of Various pH Media on Fracture Toughness and Hardness of Bilayered Reinforced Polymer and Monolithic Hybrid Ceramic

Objective: This study evaluated the effect of various pH media on fracture toughness and hardness of bi layered reinforced polymer and monolithic hybrid ceramic.
Materials and Methods: Total of 80 samples were used in this study. Samples were divided into two main groups , Poly Ether Ether Ketone (PEEK) group and Vita Enamic group. Each PEEK and Vita Enamic group were subdivided into 4 subgroups according to PH media used, control group, strong acid media (Pepsi),weak acid media(coffee),distilled water. Testing was performed before and after 24 days of pH media storage. Data was statistically analyzed using Student t-test ,paired t-test and the significance level was set at p ≤ 0.05 .
Results: Hardness results with irrespective of material type, was found that baseline subgroup recorded statistically significant highest hardness followed by pH 5.5 subgroup then pH 7 subgroup while pH 2.5 subgroup recorded statistically significant lowest hardness. Fracture toughness results with irrespective of material type, was found that baseline subgroup recorded statistically significant highest fracture toughness followed by pH 7 subgroup then pH 2.5. subgroup while pH 5.5 subgroup recorded statistically significant lowest fracture toughness Conclusion: PEEK material recorded higher fracture toughness mean value than Vita enamic while Vita Enamic material recorded higher hardness mean value than PEEK . Both material affected more by pH2.5(Pepsi)sub group followed by pH 5.5 (coffee) subgroup then pH7 subgroup when measuring hardness. Both material affected more by pH5.5(coffee) subgroup followed by pH2.5 (Pepsi) subgroup then by pH 7 subgroup when measuring fracture toughness.