The seating of MOD composite inlays was determined before and after cementation with one of three cements of different viscosities. The seating was determined by measuring the axial discrepancy. Inlays were seated by strong finger pressure or by the ultrasonic insertion (USI) technique. The axial discrepancy of luted inlays varied between 115 urn and 472 um. The axial discrepancy of inlays luted with finger pressure increased with the viscosity of the cement (Duo Cement