[Experimental research of hot alkaline solution etching treatment on zirconia/resin bonding strength].

PURPOSE: In this experiment, we applied hot alkaline solution (20%NaOH solutions) to treat the surfaces of zirconia ceramics in vitro, then evaluated the changes of bond strength of zirconia ceramics and resin cement. METHODS: Eighteen pieces of zirconia ceramic specimens were made, using the same method of grinding and polishing, and then randomly divided them into 3 groups: group A with hot alkali solution treatment (20%NaOH) (n=6), group B underwent sand blasting with a diameter of 110 ?m alumina particles (n=6), group C was as the control group. Atomic force microscope was used to measure the roughness of the surface of the specimens, and the zirconia surfaces were scanned to get topography maps, then made them into ceramic/resin-bonded specimens. After 24 h of water reservoir processing, shearing bonding strength (SBS) test was conducted and their bond interfaces were observed to investigate the lesions of different degree in these specimens. The data were analyzed with SPSS20.0 software package. RESULTS: Surface roughness was group B> group A > group C, SBS was group B>group A>group C. CONCLUSIONS: Under the condition of 180degrees centigrade, bonding strength between zirconia and resin cement after treatment with 20% NaOH solution was significantly higher than without any treatment, but lower than sand blasting treatment.