[The oral lichen planus: doubts and evidence].

Oral lichen planus (OLP) is the oral mucosal form of the lichen ruber planus disease. Its diagnostics is not an easy task. Difficulties exist in diagnosing OLP because there are no fully accepted criteria (neither clinical, nor histological) of the disease. Its etiopathogenesis is also not fully understood. Previous studies concentrated on local factors of the disease such as bad oral hygiene, bad dental condition, and smoking. These studies established that OLP is relatively independent from these factors. Besides local factors, chronic systemic diseases like diabetes and hepatitis of HCV origin were examined. Studies on the parallel occurrence of the OLP with systemic diseases in different populations led to contradictory results. This might strengthen the fact that etiological factors causing the OLP, or worsening the OLP, or playing a role in malignant changes are not the same. Our review would like to provide possible answers to questions concerning OLP.