Human Gingival Fibroblast Attachment to Smooth Titanium Disks with Different Surface Roughnesses

Peri-implantitis is a significant problem associated with dental implants. It has been hypothesized that creating a soft-tissue seal around the implant neck prevents peri-implantitis. This study aims to clarify the effects of the surface smoothness of titanium disks on soft tissues. Thus, titanium disks were prepared through electrolytic composite polishing (ECP), sisal buffing (SB), hairline polishing (HP), and laser cutting (LC). The surface roughness values of seven items was measured. For ECP, SB, HP, and LC samples, the Ra values were 0.075, 0.217, 0.671, and 1.024 μm and the Sa values were 0.005, 0.115, 0.500, and 0.676, respectively, indicating that the surface roughness was remarkably lower with ECP. Moreover, the Wsk values for ECP, SB, HP, and LC were 0.521, 1.018, -0.678, and -0.558, respectively. The smooth surfaces produced by ECP and SB were biased toward the concave surface, whereas those produced by HP and LC were biased toward the convex surface. The Rku values for ECP, SB, HP, and LC were 2.984, 11.774, 14.182, and 26.232, respectively. Only the ECP exhibited a moderate bias peak and produced an extremely smooth surface. The contact angles in the cases of ECP, SB, HP, and LC were 60.1°, 66.3°, 68.4°, and 79.3°, respectively, indicating the hydrophobicity of the titanium disks. Human oral fibroblasts were then incubated on each disk for 24 and 48 h to measure cell attachment, and no significant differences were observed. The differences in Ra and Sa did not affect cell attachment. Therefore, by applying ECP to the abutment or implant neck, the cell attachment required for soft-tissue formation while preventing bacterial adhesion can be achieved.