Laser Treatment With Methylene Blue vs. Nanoparticle-Assisted Photodynamic Therapy for Gingival Pigmentation: A Randomized Clinical Trial

This intervention consisted of applying a 0.1% conventional methylene blue solution uniformly to the pigmented gingival surface using a sterile microbrush. The photosensitizer was allowed to remain in contact with the gingiva for 2 minutes before photoactivation. Photodynamic activation was performed using a 660-nm diode laser at an output power of 100 mW in continuous-wave, non-contact mode for 60 seconds per treatment site. The gingival surface was subsequently irrigated with sterile saline to remove residual photosensitizer. Diode-laser gingival depigmentation was then performed using the 970-nm, 1.5-W continuous-wave protocol with a 320-µm fiber tip in contact mode for approximately 30 seconds per treatment site.

This intervention consisted of applying a 0.1% methylene blue nanoparticle formulation uniformly to the pigmented gingival surface using a sterile microbrush. The formulation was allowed to remain in contact with the gingiva for 2 minutes before photoactivation. Photodynamic activation was performed using a 660-nm diode laser at an output power of 100 mW in continuous-wave, non-contact mode for 60 seconds per treatment site. The gingival surface was subsequently irrigated with sterile saline to remove residual formulation. Diode-laser gingival depigmentation was then performed using a 970-nm diode laser at 1.5 W in continuous-wave mode with a 320-µm fiber tip in contact mode for approximately 30 seconds per treatment site.