Time-Dependent Changes in Salivary Antioxidants After 5-ALA Photodynamic Therapy vs. Clobetasol in Oral Lichen Planus: A Randomized Clinical Trial

Abstract

In this randomized clinical trial, we compared the effects of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) and topical clobetasol on the salivary antioxidant profile in patients with oral lichen planus (OLP) and explored their relationships with clinical outcomes. Ninety adults with OLP were randomly allocated to ALA-PDT (five weekly sessions) or clobetasol (twice daily for 14 days). Unstimulated whole saliva was collected at baseline (T0), immediately after treatment (T1), and at 3 (T3) and 6 months (T6). The activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (Px) and reduced glutathione (GSH) were determined, and nonparametric statistics were applied, including Friedman tests with Dunn’s post hoc comparisons and Spearman’s rank correlations. Both therapies induced an early decline in CAT, Px and GSH at T1, followed by partial recovery at later time points. SOD activity changed significantly over time in the clobetasol group, but not in the PDT arm. At T6, Px and GSH remained below baseline in both groups despite improvement from the immediate post-treatment nadir. No significant between-group differences were observed at individual time points, although GSH at T6 showed a non-significant trend favoring PDT. Exploratory analyses revealed modest, treatment-dependent associations between salivary antioxidant activity and lesion size, as well as between the former and pain intensity. Overall, ALA-PDT and topical clobetasol both modulated the salivary redox profile, primarily through short-term depletion of enzymatic and non-enzymatic antioxidants with incomplete recovery over 6 months, and no clear redox superiority of one modality over the other was demonstrated. These findings are hypothesis-generating and underscore the need for larger, longer-term studies with broader redox panels and more advanced between-group analyses.