Titanium Degradation Products from Dental Implants: Mechanisms of Release, Biodistribution, and Analytical Detection in Biological Matrices

Titanium-based implants remain among the most successful biomaterials in modern dentistry, but accumulating evidence demonstrates that titanium is not biologically inert under long-term physiological conditions. Mechanical loading, tribocorrosion, acidic and oxidative microenvironments, and biofilm-driven electrochemical processes contribute to progressive surface degradation and the release of titanium ions, microparticles, and nanoparticles into surrounding tissues and biological fluids. The present narrative review synthesizes current evidence regarding the mechanisms of titanium release from dental implant surfaces, the biodistribution of degradation-derived species across local and systemic biological compartments, and the analytical methodologies used to detect and characterize them. Mechanisms of electrochemical corrosion, tribocorrosion, and nanoparticle generation are critically discussed alongside biofilm-mediated acceleration of surface degradation. The biological matrices in which titanium has been measured—including peri-implant tissues, peri-implant crevicular fluid, saliva, blood, regional lymph nodes, and distant organs—are reviewed with attention to the methodologies employed (ICP-MS, SP-ICP-MS, LA-ICP-MS, SEM-EDS, TEM, XRF, and synchrotron-based approaches) and their respective strengths and limitations. Methodological heterogeneity in implant characterization, sample preparation, contamination control, and discrimination between ionic and particulate species is identified as a major source of inconsistency across the current literature. The biological consequences of titanium dissemination—including oxidative, immunological, microbiome-associated, and systemic responses—are addressed in detail in a companion review. Together, these analyses are intended to support the design of more rigorous, integrated, and clinically translatable investigations of implant-associated biomaterial degradation.