Vicker's microhardness and energy dispersive x-ray analysis of fluorapatite-leucite and fluorapatite ceramics cyclically immersed in acidic agents

This study evaluated the microhardness and elemental composition of various ceramics immersed in acidic agents. One hundred and five discs of fluorapatite-leucite (IPS d.SIGN) and fluorapatite ceramics (IPS e.max Ceram) were randomly divided into 7 groups of 15 each. Five groups were alternately immersed in acidic agents (citrate buffer solution, pineapple juice, green mango juice, cola soft drink and 4% acetic acid) for 30 min and deionized water for 5 min in 7 cycles at 37 degrees C. Two groups were continuously immersed in 4% acetic acid at 80 degrees C for 16 h and deionized water at 37 degrees C for 245 min. Vicker's microhardness and elemental composition were recorded before and after immersion. Data were analyzed using two-way repeated ANOVA and t-test at a significance level 0.05. For IPS d.SIGN, there was statistically significant difference in microhardness values between before and after immersion in the green mango, cola soft drink and 4% acetic acid for 16 h (P < 0.05). However, for IPS e.max Ceram, there was no significant difference between before and after immersion in any of the groups (P > 0.05). EDX results of both ceramics found that the elemental percentage of Na, K, Zr, Al and Si decreased after being immersed in acidic agents.