CHEMICAL VERSUS PHYSICAL SURFACE MODIFICATION OF TITANIUM DENTAL IMPLANTS: A COMPARATIVE REVIEW OF SANDBLASTED, LARGE-GRIT, ACID-ETCHED (SLA) AND FEMTOSECOND LASER-ABLATED SURFACES

Surface topography governs the rate and quality of osseointegration of titanium dental implants. The sandblasted, large-grit, acid-etched (SLA) surface represents the established chemical-subtractive paradigm and remains the clinical benchmark21[SP1.1], whereas femtosecond (fs) laser ablation has emerged as a physical-subtractive alternative that promises deterministic topographic control, superior surface purity and a thickened, crystalline oxide without the mechanical penalties of acid etching. This review critically compar es the two paradigms across four domains: surface metrology and chemistry, In-vitro biological response, In-vivo biomechanical fixation and histomorphometry, and clinical implications. Evidence indicates that SLA reliably produces a moderately rough (Sa 1–2 µm) surface with high bone-to-implant contact and more than 95% five-year survival, but is constrained by residual alumina embedding, hydrogen-induced embrittlement and stochastic topography. Femtosecond laser processing generates hierarchical micro/nano structures (laser-induced periodic surface structures, LIPSS) with a five-fold thicker oxide, controllable anatase/rutile content, contaminant-free chemistry and markedly enhanced osteoblast adhesion, at the cost of frequently hydrophobic wettability, limited long-term in vivo data and a modest fatigue reduction. The strongest bone-bonding biomechanical data derived from laser-structured (predominantly nanosecond) surfaces, while fs-specific evidence remains largely in vitro and material-scientific. It is concluded that fs-laser ablation is a credible, and in several respects superior, engineering platform whose osteogenic and antibacterial promise is not yet matched by clinical validation. Rational, scenario-based selection guidelines and future directions toward “smart” dual-function surfaces are proposed.