摘要： Background: The aim of the study was to clinically evaluate the efficacy of photodynamic therapy in treatment of reticular oral lichen planus (OLP). Methods: Fifty patients aged 26-84, with 124 OLP lesions in total, underwent photodynamic therapy (PDT) mediated with topically applied 5% 5-aminolevulinic acid. ALA was activated by a custom-made diode lamp with a high-power LED emitting light at 630 nm and 300 mW delivered through an optical fiber probe. A light exposure dose was 150 J/cm2. The therapy comprised of 10 weekly illumination sessions. The lesions’ response to the therapy was macroscopically measured in millimeters with a periodontal probe and clinically evaluated at each session, then on completion of the series and throughout the 12-month follow-up. Results: The baseline mean size of lesions was 3.99 cm2±3.73. The lesions on the buccal mucosa and lips (lining mucosa) were larger than those on the gingiva and tongue (masticatory mucosa) – 4.58 cm2±4.01 and 2.93 cm2±2.91 respectively. On completion of the therapy 109 sites improved, including 46 in complete remission. The mean reduction in size was 62.91% (p=0.000000). 12-month after therapy mean reduction of the lesions was 78.7% (p=0.000000), specifically 79.48% (p=0.000000) within the lining mucosa and 76.11% on the masticatory mucosa. Conclusions: The results suggest that PDT may become an alternative method for treating the reticular form of OLP. The results proved that ALA-mediated photodynamic therapy with a 630 nm light was effective and as such it can be used as an optional treatment for symptomatic OLP.