Residual-Free Micro–Nano Titanium Surfaces via Titanium Blasting and Single Acid-Etching: A Cleaner Alternative

Background: Traditional sandblasted large-grit acid-etched (SLA) surface treatments frequently utilize alumina (Al2O3) blasting, which may leave residual particles embedded in implant surfaces, potentially compromising biocompatibility and osseointegration. This study investigates a contamination-free alternative: titanium dioxide particle (TiO2) blasting followed by hydrochloric acid (HCl) etching, aimed at generating a cleaner, hierarchical micro–nano-textured surface. Methods: Grade IV titanium disks were treated either with TiO2 sandblasting alone or with an additional HCl etching step. Surfaces were analyzed via atomic force microscopy (AFM), scanning electron microscopy (SEM), contact angle measurements, and profilometry. hFOB osteoblasts were cultured to assess adhesion, proliferation, metabolic activity, and morphology. Results: The combination treatment produced a more homogeneous micro–nano structure with significantly increased roughness and a cleaner surface chemistry. Osteoblast proliferation and metabolic activity were notably improved in the TiO2 and HCl group. SEM imaging showed a more organized cytoskeletal structure and pronounced filopodia at 72 h. Conclusions: Titanium blasting combined with HCl etching yields a cost-effective, contamination-free surface modification with promising early-stage cellular responses. This approach represents a safer and effective alternative to conventional SLA treatment.