Purpose: The aim of the present study was to establish a noninvasive method for quantitative analysis of supra- and subgingival biofilm formation on dental implants considering different surface modifications. Materials and Methods: Patients of both sexes were included. They had to be in generally good health, partially edentulous, and the recipient of at least 1 screw-type implant with an abutment possessing supra- and subgingival areas. Healing abutments were inserted for 14 days. The abutment surfaces were divided into quadrants that were sandblasted, ground, acid-etched, and untreated (with the latter surface as a control). Biofilm formation on the healing abutments was analyzed using scanning electron microscopy, including secondary-electron and Rutherford backscattering-detection methods. Calculation of biofilm-covered surfaces was performed depending on grey-values, considering supra- and subgingival areas. After calculating absolute and relative biofilm-covered surfaces depending on localization, the influence of surface modification on biofilm formation was analyzed. Results: Fifteen healing abutments were inserted in 11 patients. In all surface properties plaque adhesion in supragingival areas was significantly higher (17.3% ± 23.1%) than in subgingival areas (0.8% ± 1.0%). Biofilm accumulation in supragingival areas was significantly increasing by higher surface roughness, whereas this influence was not detected in subgingival areas. Conclusion: The described method is valuable for investigation of supra- and subgingival biofilm adhesion on surface-modified implant abutments. There was a significant influence of surface localization (supra- and subgingival) as well as surface modification on biofilm formation. (Case Control Study) Schlagwörter: abutment, biofilm, implant, scanning electron microscopy, surface roughness