This randomized, double-blind clinical trial evaluates the therapeutic effects of curcumin in nanogels compared to 0.1% fluocinolone acetonide oral paste in the management of atrophic-erosive oral lichen planus (OLP). The study aims to determine whether curcumin nanogels, a natural treatment with enhanced bioavailability, are as effective and better tolerated than standard corticosteroid therapy.

Oral lichen planus (OLP) is a chronic, immune-mediated inflammatory condition that causes painful mucosal lesions and significantly impairs patients' quality of life. Although topical corticosteroids are the standard treatment, their long-term use is associated with adverse effects. Curcumin, a natural compound with anti-inflammatory and antioxidant properties, has shown promise as an alternative treatment. However, its clinical application is limited by poor bioavailability.

This randomized, double-blind, controlled clinical trial aims to compare the therapeutic effects of curcumin in nanogels and 0.1% fluocinolone acetonide oral paste in patients with atrophic-erosive OLP. Thirty eligible participants will be randomly assigned to either the curcumin nanogel or fluocinolone group, and treatment outcomes will be evaluated using the Oral Lichen Planus Disease Activity Scale (OLP-DAS) and a patient satisfaction questionnaire over a 4-week period.

The study is conducted at the Faculty of Dentistry, Chulalongkorn University, and seeks to evaluate whether curcumin nanogels offer comparable therapeutic efficacy to corticosteroids, with potentially fewer side effects.

Inclusion Criteria:

• Age 18 years or older
• Ability to provide written informed consent
• Clinically and histopathologically confirmed diagnosis of erosive or atrophic oral lichen planus (OLP)
• Presence of symptoms (NRS pain score > 0 at baseline)
• Ability to communicate and follow instructions
• Willingness to apply oral paste treatment and comply with study protocol

Exclusion Criteria:

• Pregnancy or lactation
• Current orthodontic treatment
• Uncontrolled diabetes mellitus (HbA1c > 7% or FPG > 130 mg/dL)
• Use of anticoagulants or antiplatelet agents
• Severe dry mouth (Challacombe score > 7)
• History of gastric ulcers, duodenal ulcers, or gallstones
• Presence of any active malignancy or infection
• Use of topical/systemic treatment for OLP in the past 2 weeks
• Current use of immunosuppressants
• Known allergy to corticosteroids or herbal agents such as turmeric
• Diagnosis of oral lichenoid contact lesion or graft-versus-host disease (GVHD)
• History of allogeneic bone marrow transplantation
• Current smokers