Patients in this group will undergo laser-assisted gingival depigmentation using a diode laser (970 nm wavelength, 2.0 W power, continuous mode) with a 200 µm fiber tip applied for 30 seconds per site in contact mode.

This group will receive photodynamic therapy (PDT) using a conventional methylene blue solution (0.1%), applied for 2 minutes before activation with a 660 nm diode laser (1.5 W, pulsed mode, 60 seconds per site). This will be followed by laser-assisted gingival depigmentation using a diode laser (970 nm wavelength, 2.0 W power, continuous mode, 200 µm fiber tip, 30 seconds per site).

Patients in this group will receive PDT with methylene blue nanoparticles (0.1%) applied for 2 minutes before activation with a 660 nm diode laser (1.5 W, pulsed mode, 60 seconds per site). This will be followed by laser-assisted gingival depigmentation using a diode laser (970 nm wavelength, 2.0 W power, continuous mode, 200 µm fiber tip, 30 seconds per site).

This intervention involves the use of a diode laser (970 nm wavelength, 2.0 W power, continuous mode) with a 200 µm fiber tip. The laser is applied in a sweeping motion over the pigmented gingiva in contact mode for 30 seconds per site to achieve depigmentation.

The primary outcome will be assessed by evaluating changes in gingival pigmentation using clinical photographs and a standardized pigmentation index. Digital images of the treated gingival areas will be analyzed for pigmentation intensity reduction using imaging software. The pigmentation index scores range from:

Score 0: Absence of pigmentation

Score 1: Spots of brown to black color

Score 2: Brown to black patches without diffuse pigmentation

Score 3: Diffuse brown to black pigmentation

The duration required for complete epithelialization of the treated gingival area will be recorded. Visual inspection at follow-up visits will determine the time until there is no visible inflammation, erythema, or delayed healing.