Oral lichen planus (OLP) is a chronic inflammatory and immune-mediated disease affecting the oral mucosa. OLP presents with asymptomatic, lacelike white stripes and/or symptomatic red, ulcerated mucous membranes. Eating, drinking and oral hygiene procedures may be painful resulting in reduced quality of life (QOL). Photodynamic therapy (PDT) is a new suggestion for OLP treatment PDT is a successful treatment mo- dality for premalignant and malignant diseases of head and neck,gastrointestinal tract, lung, and skin

In this study, the effect of photodynamic therapy with topical corticosteroid in oral lichen planus patients was compared

In this study, the efficacy of toluidine blue-mediated photodynamic therapy and topical triamcinolone acetonide 0.2% on decreasing pain and size of OLP lesions was compared.

This randomized, clinical trial compared the therapeutic effect of photodynamic therapy on symptomatic OLP (atrophic/ erosive/ulcerative forms) with triamcinolone acetonide 0.2%. The protocol of the clinical trial, which was conducted according to the ethical principles of Helsinki Group I toluidine blue-mediated photodynamic therapy Group II photodynamic therapy GroupIII laser sham + triamcinolone acetonide 0.2%

Inclusion Criteria:

• . The patients with clinical or histopathological diagnosis of bilateral atrophic or erosive OLP (symptomatic OLP) who signed the written consent form were recruited.

Exclusion Criteria:

• Patients with drug-induced or contact lichenoid reactions, patients receiving any treatment for OLP in 2 months prior to the study, pregnant or lactating women, patients with uncontrolled systemic disease, and patients with photosensitivity