Background: Oral lichen planus is a chronic mucocutaneous disease of uncertain etiology. Inflammatory cell infiltrate plays an important role in pathogenesis of oral lichen planus. It is said that hyperplastic epithelium is seen where the inflammatory cell infiltrate is mild while beneath atrophic epithelium dense inflammatory cell infiltrate is evident. Studies have shown negative correlation between thickness of the epithelium and thickness of inflammatory cell infiltrate. Morphometric studies in oral lichen planus are very scanty and have been performed using stage micrometer and eye piece graticule. Using Image Analysis Software can avoid inter-observer variations which has not been done till date. Aim and Objectives:The present study aimed at evaluating thickness of epithelium and thickness of inflammatory cell infiltrate and to determine any existing relation between the same using Image Analysis Software. Other histopathologic features were also evaluated.Materials and method: 58 confirmed cases of oral lichen planus from buccal mucosa were retrieved from department archives. 6µ thick sections were stained with Hematoxylin and Eosin. Six non-overlapping fields were selected randomly from each section and photomicrographs were captured under 4x objective using Trinocular Research Microscope. Morphometry was done using Image Analysis Software and data was stored in Microsoft excel for statistical analysis. Results:In present study the mean of epithelium thickness was 281.2059 and inflammatory cell infiltrate thickness was 330.2540. An inverse correlation was observed. As the thickness of inflammatory cell infiltrate increased there was a decrease in thickness of epithelium (Coefficient -0.156). Conclusion:Thickness of the epithelium may vary according to the site, however in this study all cases were from buccal mucosa. Inflammatory cell infiltrate influences overlying thickness of epithelium and determines its nature. How to cite this article:Ramya VV, Nandini DB, Praveen SB, Madhushankari GS. Thickness of the epithelium and the inflammatory cell infiltrate in oral lichen planus. A morphometric study. CODS J Dent 2014;6;78-82 Source of support: Nil. Conflict of interest: None Declared.Hyperplasia, acanthosis, hyperkeratosis are usually observed phenomena in the epithelium in oral lichen planus. The underlying inflammatory cell infiltrate influences the nature of epithelium as observed in this morphometric study.

Background and Objectives: Oral lichen planus (OLP) is a chronic disease of uncertain cause commonly affecting oral cavity. Although the WHO has designated OLP as a “potentially malignant disorder,” controversies exist regarding its malignant potential. Collagen forms the principal component of stroma or extracellular matrix and its role in carcinogenesis is widely studied in other premalignancies. Although collagen at the basal complex of OLP is widely explored, studies on collagen in the connective tissue stroma are not reported to date. We aimed to observe the nature of collagen in connective tissue stroma of OLP using picrosirius red stain (PSR) under polarized microscope and compare with buccal mucosa without any pathology related to exposure to tobacco and other oral carcinogens, carcinoma in situ (Ca in situ), and early invasive squamous cell carcinoma (EISCC). Materials and Methods: Eighty samples were observed, with twenty samples in each study group. Two 4–6-μ thick sections were obtained from the archival blocks. One section was stained with hematoxylin and eosin for confirming the diagnosis, whereas PSR staining was done for the other section. Both sections were analyzed using a polarizing microscope for evaluating the polarization colors of collagen. The images captured were stored on a computer. Five nonoverlapping fields were selected from each section in all groups and the thickness of five collagen fibers from each section was measured in microns using image analysis software and the polarizing color was also noted. The values obtained were compared using Kruskal–Wallis H-test and Chi-square test. We also used Mann–Whitney U-test for intergroup comparison. Results: The mean width of thick as well as thin fibers was more in controls than Ca in situ, OLP, and EISCC in decreasing order. Mature fibers were predominant in the controls than Ca in situ, OLP, and EISCC in decreasing order. Immature fibers were predominant in EISCC, followed by OLP, Ca in situ, and controls. Comparison of collagen in OLP and Ca in situ showed no statistically significant result in terms of thickness and polarization colors confirming a similarity in the nature of collagen in these two lesions. Conclusion: The stromal collagen of OLP was comparable to Ca in situ suggesting a change in the structure and organization of collagen probably attributed to the role of inflammatory mediators. A study with bigger sample size is recommended to evaluate the role of collagen in malignant transformation of OLP.