Scanning electron microphotograph of retrieved dental implants: (a) dental implant from patient 1 showing organic debris on cone area, (b) residual bone in apical area, (c) residues as dark areas (arrows) in the apico-lateral area, (d) grooves and ridge along the machined direction on retrieved implant, (e) higher magnification of grooves with proteinaceous material (arrow), (f) residues as dark areas (arrow) and contaminants (arrow heads).