EFFECT OF SURFACE FINISHING METHODS, pH AND TEMPERATURE ON ROUGHNESS AND ION RELEASE OF CERAMICS

Abstract

Objective: There is a lack of information on dental ceramics long-term ion releases at different conditions and effect of surface finishing techniques on ion leaching. The difference between the amount of ions released from a polished ceramic surface and that released from glazed surfaces is unknown. This study aimed to investigate surface changes and ion leaching from dental ceramics after corrosion and to assess differences between two surface finishing methods. Material and Method: 20 ceramic disks (8x2 mm) (Empress II, Zirkonzahn, Noritake Cerabien ZR, Finesse, Vita VM7) were fabricated and categorized into autoglazed and polishing (n=10). The surface roughness (Ra) was evaluated before and after corrosion. After subjecting the specimens to in vitro corrosion (pH 4.5-pH 7-pH 9 in water at 37 degrees C +/- 2 degrees C for 18 hours and at pH 2.4 in 4% acetic acid solution at 80 degrees C +/- 2 degrees C for 18 hours), ion release was assessed. Data were analyzed using ANOVA and Bonferroni Test (alpha=0.05). Multiple comparisons were analyzed by Student t-test. Results: Al, Na, Li, Si ions were leached from all ceramic groups. Ra was significantly changed between the groups at various pH (p < 0.05). Post corrosion Ra values were lower than pre corrosion for polished groups. Conclusion: Glazed surfaces are more resistant to corrosion for high sintering ceramics. Polishing can also be a reliable technique when restorations removal is avoided.