From Laser Process to Function: Laser Texturing, Modification and Cleaning of Orthodontic Metallic Biomaterials—A Critical Appraisal of the Corrosion, Metal-Ion Release, Bacterial Adhesion and Friction Evidence for Stainless Steel, NiTi and β-Ti

Laser surface engineering is increasingly proposed for orthodontic alloys, yet “laser texturing”, “laser modification” and “laser cleaning” denote physically distinct processes that act on the surface in opposite directions. This critical review asks whether reported laboratory benefits for corrosion, metal-ion release, bacterial adhesion and friction transfer to the bracket–archwire couple in the oral environment. Evidence was appraised against a process → surface state → laboratory response → potential clinical performance framework that treats the laser-induced surface state as the mediating variable. First, the orthodontic bracket–archwire evidence base comprises three studies on stainless steel: two of bracket-slot texturing and one of laser welding. The only such work identified on other alloys is a further welding study. The stated searches identified no eligible study on laser-engineered orthodontic β-titanium. Second, no identified study measures metal-ion release from laser-textured metal in a dental context, and static electrochemical parameters cease to predict ion release where mechanical assistance dominates. Third, antibacterial and friction benefits are demonstrated under conditions—mono-species assays without a salivary pellicle and sliding velocities orders of magnitude above clinical—that cannot represent the oral interface. These are gaps in evidence, not evidence of no effect. A minimum reporting dataset is proposed.