Background:Oral lichenoid lesions or reactions (OLLs/OLRs) are clinical and histological contemporaries of the classical oral lichen planus (OLP) that have generated a lot of debate in literature. In contrast to the idiopathic nature of OLP, OLLs are often associated with a known identifiable inciting factor. A superficial examination of these lesions clinically and histologically often reveals many similarities with OLP, but recent data indicate that distinguishable features do exist and form the basis of most classifications.Aims and Objectives:This paper attempts to collate available data in English literature on OLLs, highlight distinguishing features clinically and histologically and reflect on the malignant transformation potential and treatment modalities of the condition.Materials and Methods:A comprehensive search of medical and dental databases including PubMed, Ovid, Cochrane, Pubget, Researchgate, and non-medical search engines were utilized for the review. The search words included “oral lichen planus”, “oral lichenoid lesions”, “oral drug reactions”, “lichenoid dysplasia”, and “adverse effects of dental materials”.Review Results:OLLs seem to grossly underrated and most cases were clubbed as OLP. Definite clinical and histological features were uncovered to establish the identity of this lesion. Associations with dental restorative materials, drugs, and medications have been conclusively proven in the etiology of this condition. Specific markers are being utilized to diagnose the condition and monitor its progress.Conclusion:Substantial differentiating features were uncovered to delineate OLLs as a separate entity with definite etiology, pathogenesis, and a high malignant transformation rate compared with OLP.

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Background:Amelogenins are the major enamel proteins that play a major role in the biomineralization and structural organization of enamel. Aberrations of enamel-related proteins are thought to be involved in oncogenesis of odontogenic epithelium. The expression of amelogenin is possibly an indicator of differentiation of epithelial cells in the odontogenic lesions.Aims and Objectives:The present study aimed to observe the expression of amelogenin immunohistochemically in various odontogenic lesions.Materials and Methods:Paraffin sections of 40 odontogenic lesions were stained immunohistochemically with amelogenin antibodies. The positivity, pattern and intensity of expression of the amelogenin antibody were assessed, graded and statistically compared between groups of odontogenic cysts and tumors.Results:Almost all the odontogenic lesions expressed amelogenin in the epithelial component with the exception of an ameloblastic carcinoma. Differing grades of intensity and pattern were seen between the cysts and tumors. Intensity of expression was uniformly prominent in all odontogenic lesions with hard tissue formation. Statistical analysis however did not indicate significant differences between the two groups.Conclusion:The expression of amelogenin antibody is ubiquitous in odontogenic tissues and can be used as a definitive marker for identification of odontogenic epithelium.