Effects of different electrolytes for micro-arc oxidation on the bond strength between titanium and porcelain

Purpose The aim of this study is to investigate the effects of different electrolytes on the titanium–porcelain bond strength after micro-arc oxidation (MAO) treatment. Methods Three electrolytes at the same concentration were used as MAO reaction solutions: Na 2 SiO 3 , KF, and MgSiF 6 . Blasting treatment was chosen as a control. After MAO treatment in each electrolyte, the titanium–porcelain bond strengths were measured by the three-point bending test, as described in ISO 9693. The morphologies and elemental compositions of the MAO coating on the titanium substrate were evaluated by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The interface between the titanium and porcelain was also observed by SEM and EDS. Results The MAO coatings created in different electrolytes exhibited completely different morphologies and compositions. The bond strengths of the Na 2 SiO 3 and MgSiF 6 groups were significantly higher than those of the other groups (p < 0.05). Additionally, the titanium–porcelain interfaces were compact in the former two groups, whereas pores and cracks were visible at the interfaces in the other groups. Conclusions These results indicate that MAO treatment with an appropriate electrolyte could be an effective method to increase the titanium–porcelain bonding strength. According to ISO 9693, titanium–porcelain restorations subjected to MAO treatment with an appropriate electrolyte could be appropriate for clinical use.