Objective The aim of this study was to evaluate the effects of nano -silica coating prepared by different concentration silica sol on fracture strength of glass infiltrated alumina ceramic after bonding. Methods Five In-Ceram alumina ceramic groups were fabricated to receive different surface treatments as group A, B, C, D, E. Each ceramic disc was bonded to dentin with dual -cured resin cement, and then fracture strength of these samples was tested. After one sample of each group as before, scanning electron microscopy and energy dispersive spectrometer was used to analyze the interface. Results There existed differences among the five groups（P
