Er, Cr: YSGG laser ablation combined with photodynamic therapy in the treatment of gingival leukoplakia: two case reports and literature review

To evaluate the clinical feasibility and potential for malignant transformation prevention of hyperkeratotic oral leukoplakia (OLK) treatment using erbium, chromium:yttrium-scandium-gallium-garnet laser (Er,Cr:YSGG) ablation combined with 5-aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT), providing a reference for clinical practice.

Two cases of histopathologically confirmed gingival leukoplakia were treated. Following Er,Cr:YSGG (wavelength: 2,780 nm) ablation of the hyperkeratotic layer, 20% ALA solution was topically applied for 3 hours, followed by irradiation with a 635 nm diode laser (energy density: 100 J/cm²). Follow-up assessments included lesion regression and exfoliative cytology DNA ploidy stability, supplemented by a systematic literature review on OLK treatment advancements.

Case 1: at 1-year follow-up, > 90% lesion regression was observed (residual: 2 mm circular white patch) without recurrence, with stable diploid DNA ploidy. Case 2: complete lesion resolution and no recurrence at 1 year, with stable diploid DNA ploidy. Literature review showed that pharmacological therapies ameliorate OLK symptoms but fail to halt malignant progression, while surgical interventions carry recurrence risks. PDT demonstrates unique advantages by selectively targeting dysplastic cells. However, uneven ALA penetration due to the keratin barrier limits efficacy. Compared to needling, diode laser, or CO₂ laser pretreatment, Er,Cr:YSGG leverages water absorption for precise, low-thermal keratin ablation, substantially enhancing tissue permeability and optimizing ALA diffusion, thereby improving PDT outcomes.

Er,Cr:YSGG ablation combined with PDT serves as an optimized regimen for hyperkeratotic OLK, offering a novel approach to mitigate OLK carcinogenesis.