Effects of diode laser parameters on thermal response of RBM, SLA, and additively manufactured titanium surfaces

This study aimed to investigate the effects of diode laser parameters on the thermal response and surface morphology of RBM (Resorbable Blast Media), SLA (Sandblasted, Large-grit, Acid-etched), and additively manufactured Ti6Al4V titanium surfaces, and to determine whether surface type influences heat distribution and integrity, which is clinically relevant in peri-implantitis treatment. A total of 144 titanium discs with three different surface treatments (RBM, SLA, and additively manufactured Ti6Al4V as the control group) were irradiated with a 940 nm diode laser at varying power levels (1 W, 2 W, 3 W), durations (30 s, 60 s), and modes (continuous, pulsed). Surface temperatures were recorded using thermal imaging. Morphological and elemental changes were evaluated via Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) analyses. A four-way Aligned Rank Transform Analysis of Variance (ART ANOVA) was used to analyze the effects of variables. Temperature increases were significantly influenced by all tested variables (p < 0.001). The RBM group exhibited the highest peak temperature (185 °C at 3 W pulsed mode, 60 s), while SLA surfaces consistently showed the lowest (39.9 °C at 1 W continius mode, 30 s). Pulsed mode and longer exposure times produced higher temperatures, except at 1 W, which resulted in the lowest temperature rise regardless of surface treatment. SEM images revealed mild surface alterations at higher power, with RBM exhibiting localized depressions and SLA displaying minor fragmentation of surface textures. EDS analysis indicated no major changes in elemental composition post-irradiation. The study highlights that different titanium surface types respond distinctly to diode laser irradiation, with RBM surfaces being more thermally reactive. Uniform laser protocols may not be appropriate for all implant surfaces. Careful consideration of power, duration, and surface characteristics is essential to avoid potential thermal damage during peri-implantitis treatment.