In Vitro Method for Assessing Laser Titanium Interactions Using Er,Cr:YSGG and Diode Lasers

This study presents a standardized in vitro protocol to evaluate the thermal response and surface alterations of titanium during Er,Cr:YSGG and diode laser irradiation under manufacturer-recommended soft-tissue settings. Custom Grade 4 titanium cylinders with an internal channel enabled direct-temperature measurement via an embedded thermocouple, allowing controlled assessment of laser-induced thermal changes. To ensure geometric consistency and minimize operator-dependent variability, a 3D-printed stabilization system was used to standardize the irradiation angle, sweep trajectory, and tip movement. Surface modifications following laser exposure were quantitatively and qualitatively characterized using complementary techniques, including profilometry for roughness analysis, scanning electron microscopy for micromorphologic evaluation, and atomic force microscopy for nanoscale topographic assessment. Diode-laser irradiation produced power- and time-dependent temperature elevations, with the highest parameter combinations exceeding the clinically accepted 10 °C safety threshold. In contrast, all tested Er,Cr:YSGG conditions remained below this limit, indicating distinct wavelength-dependent thermal behavior. Both laser systems induced significant increases in surface roughness relative to the untreated control surface, while imaging analyses revealed wavelength-dependent differences in micro and nanoscale morphology. Collectively, this protocol provides an experimental framework for systematic investigation of laser-titanium interactions and may support safer, evidence-based parameter selection for laser-assisted soft tissue procedures performed near implant components.