Microcryst. aluminosilicate and Li disilicate ceramic cylinders (diam. 5 mm) were surface-treated by sandblasting with air-borne Al2O3(diam. 50 pm or 110 pm), etching with HF (9%) or by combination of both methods, and then studied for chem. compn. of the surface and then for bond strength to a dental composite. Both, HF etching and tribochem. surface treatment resulted in an increase in the bonding strength.