The aim of this study is to test the adhesion of human gingival fibroblasts (HGFs) and epithelial cells (HGEs) to titanium surface by RGD grafting for dental implant, and to obtain an effective perimucosal seal of soft tissue to the implant. RGD peptides were covalently attached to the titanium surface by CDI activation method to improve the adhesion of gingival cells to the titanium dental implants. HGFs and HGEs were inoculated on commercially pure (CP) titanium and RGD-grafted titanium. The number of attached and proliferated cells was quantified by morphometric analysis using immunofluorescence. The results showed that the bioactive peptide RGD was grafted on CP titanium by CDI activation method. The RGD grafting exhibited that the number of attached and proliferated fibroblasts and epithelial cells were higher than that on CP titanium. The RGD-grafting is advantageous to gingival cells adherence to the surface of titanium implant. (c) 2005 Elsevier B.V. All rights reserved.