Impact of PDT and Topical Corticosteroids on Taste Perception and Salivary Oxidative Stress Markers in Patients With OLP

Overview

Oral lichen planus (OLP) is a long-term inflammatory disease affecting the lining of the mouth. It may cause pain, burning sensations, discomfort, and changes in the appearance of the oral mucosa. Some patients may also notice changes in their ability to recognize different tastes. The aim of this study is to compare two treatments used for OLP: photodynamic therapy (PDT) and topical corticosteroid therapy. PDT is a light-based treatment in which a special gel containing 5-aminolevulinic acid is applied to the affected areas and then activated using a medical light device. Topical corticosteroids are anti-inflammatory medicines applied directly to the oral lesions. Participants are randomly assigned to receive one of these two treatments. Their ability to recognize sweet, sour, salty, and bitter tastes is assessed using special taste strips before treatment and immediately after therapy is completed. The size of the oral lesions and the severity of symptoms, such as pain and burning, are also evaluated. Saliva samples are collected before treatment, immediately after treatment, and 3, 6, and 12 months after therapy. These samples are used to measure cortisol and several substances related to inflammation and cellular stress, including malondialdehyde, advanced oxidation protein products, peroxynitrite, nitrotyrosine, and advanced glycation end products. The results may help researchers better understand how photodynamic therapy and topical corticosteroids affect taste perception, oral symptoms, lesion healing, and biological changes in the saliva of patients with OLP. The findings may also support the selection of the most appropriate treatment in clinical practice.

Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa that is frequently associated with pain, burning sensations, and impaired quality of life. Alterations in gustatory function have also been reported in patients with OLP; however, the effects of different therapeutic approaches on taste perception and salivary biomarkers of oxidative, nitrosative, and carbonyl stress remain insufficiently investigated. The aim of this randomized clinical trial is to evaluate and compare the effects of 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) and topical corticosteroid therapy (CT) on gustatory function, clinical outcomes, and selected salivary biomarkers in patients with clinically and histologically confirmed OLP. Participants are randomly allocated to one of two parallel treatment groups: (1) ALA-PDT using a 5% 5-aminolevulinic acid mucoadhesive emulgel followed by irradiation with a 630 nm LED light source, administered in five weekly sessions; or (2) topical corticosteroid therapy with clobetasol propionate applied twice daily for two weeks. Gustatory function is assessed using standardized taste strips evaluating sweet, sour, salty, and bitter taste perception, with scores ranging from 0 to 4 for each taste modality and a total taste score ranging from 0 to 16. Taste perception is evaluated before treatment initiation and immediately after completion of therapy. Salivary concentrations of cortisol, malondialdehyde (MDA), advanced oxidation protein products (AOPP), peroxynitrite, nitrotyrosine (NT), and advanced glycation end products (AGEs) are assessed before treatment, immediately after therapy completion, and at 3, 6, and 12 months following each therapeutic intervention. These measurements are intended to evaluate longitudinal changes in psychological stress and oxidative, nitrosative, and carbonyl stress associated with OLP and its treatment. Additional clinical outcomes include changes in lesion size and subjective symptom severity assessed using a 10-point Visual Analog Scale (VAS). This study aims to provide evidence on the comparative effectiveness of ALA-PDT and topical corticosteroid therapy in modulating taste perception, clinical manifestations, and salivary stress-related biomarkers in patients with OLP. The findings may contribute to a better understanding of the biological effects of both therapeutic approaches and support evidence-based treatment decision-making.