- for OLP patients: younger than 18 years, hepatobiliary system diseases, lichenoid reaction (amalgam, drugs) or lichen planus with lesions in contact to restorative materials (Zakrzewska et al, 2005), the current comparative systemic or local anti-inflammatory treatment (antibiotics, corticosteroids, non-steroidal antirheumatic drugs, chemotherapeutics) (Lo Muzio et al, 2001; Nolan et al, 2006; Rodriguez et al, 2007) and pregnancy.