Figure 5.

SEM photos representing the surface topography of composite blocks. (a) Control, (b) Diamond stone roughening, (c) Hydrofluoric acid etching, (d) Silica Coating. SR revealed uneven surfaces with pits and porosities with the existence of the grinding marks from diamond stone [Figure 5b]. HF etching was associated with partial degradation of the resin matrix and little evidence of microprosities and undercuts [Figure 5c]. In SC group, micromechanical retentive features were evident with the presence of attached silica/alumina particles [Figure 5d]