The success of dental implants depends mainly on osseointegration and gingival sealing. Therefore, early attachment and spreading of epithelial cells might be critical for a positive outcome. Research in dental implant materials has primarily focused on surface roughness, defined by the average roughness (Ra) index, as it promotes the process of osseointegration. This study explored its influence on soft tissue attachment by looking mainly at adhesion, proliferation, and spreading of primary human cells belonging to the epithelial lineage. Characterized human gingival keratinocytes, gingival and epithelial progenitor cells were seeded on machined (S1; Ra = 0.3 to 0.6 μm), Ti-Unite (S2; Ra = 1.2 μm), and SLA (S3; Ra = 2 μm) implants. Cell adhesion with early proliferation and spreading were evaluated by combining a biochemical vitality test with imaging analyses. Findings showed that adhesion was significantly higher on S1 (36% ± 2%) and S2 (44% ± 7%) than on S3 (23% ± 6%), while early proliferation was slightly improved on S1. The resulting data, obtained through an innovative and easily reproducible in vitro method, suggest that implant surface roughness affects epithelial cell adhesion and proliferation.