Evaluation the Flexural Strength of Emax Cad and E_Max Press After Thermocycling Ageing

Aim: To investigate the impact of thermocycling ageing on the flexural strength of E-max cad and E-max press The objective of this research is to evaluate the impact of aging via various thermocycling protocols on the flexural strength of a feldspathic ceramic. Material and Methods: Thirty six bars of ceramic, ivoclar e max, with dimensions of 16×4×2 mm were utilized. Bars were distributed randomly into three groups (n=6) that were defined in accordance with the number of thermal cycles (TCy): G0-no TCy; G5000-5000 cycles of TCy, G10000-10 TCy. After aging, samples were subjected to a three-point bending test in a universal test machine with a speed of 1mm/min and a load of 1kgf until the catastrophic failure was reached. Results: Concerning the mechanical test, the following values of mean and standard deviation values (MPa), were obtained: G0cad (612.12± 83.16) ; G5000cad (445.44 ± 34.99); G10000cad (366.34± 41.30) and G0press (534.09±42.83) ;G5000press (428.68±17.40) and G10000press (382±38.49).Variance analysis of was conducted using the regression equation (p=0.387) and it showed that there was a significant correlation between the flexural strength and the thermal cycles number. Conclusion: One can conclude that aging in water per se through various temperature cycles numbers has an effect on the flexural strength of a feldspathic ceramic. The thermocycling of both type of lithium disilicate has negative effect on the flexural strength, Cad ceramic showed more significant decrease in flexural strength than press ceramic which was less negatively affected.