Isfahan University of Medical SciencesDental Research Journal1735-33276220100414Human Papilloma Virus as a Possible Factor in the Pathogenesis of Oral Lichen Planus8989Saye MohhamadRazaviAssociate Professor, Department of Oral Pathology and Torabinejad Dental Research center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan. salehi_m@dnt.mui.ac.irParichehrGhalayaniMohammadRezaSalehiHAttarzadehMahdiShahmoradi20101107Background: Oral lichen planus (OLP) is a common chronic inflammatory mucocutaneous disease. Clinical diagnosis of OLP requires clinical work-up and histologic examination to rule out possible dysplasia and carcinoma. It is possible that oral mucosal viral infections including HPV infection may have a causative role in OLP pathogenesis. The aim of this study was to examine the co-incidence of human papilloma virus type 18 and oral lichen planus. Methods: This study was a case-control study. Twenty nine paraffinized specimens of previously diagnosed oral lichen planus and 14 paraffinized specimens of nonpathogenic mucosa were studied. Polymerase Chain Reaction ( PCR)  analyze used for detection of DNA HPV 18 .The data were analyzed with SPSS software and Fisher’s exact test was used to find the possible relation between HPV18 infection and oral lichen planus. Results: Nine out of 29 (31.0%) lichen planus samples and one out of 14 (7.1%) controls were HPV 18 positive. No significant correlation (P = 0.128) was observed between HPV18 infection and oral lichen planus. Conclusion: According to the findings there might be a co-incidence of human papilloma virus type 18 and oral lichen planus. Keywords: Human papillomavirus 18, Lichen Planus, Oral, Polymerase chain reaction.