Oral lichenoid lesions related to contact are defined as oral-cavity eruptions with an identifiable etiology, and are clinically and histologically similar to oral lichen planus. Within this group are found oral lichenoid lesions related to contact with dental materials (OLLC), the most common being those related to silver amalgam. Currently, it remains difficult to diagnose these lesions due to the clinical and histopathological similarity with oral lichen planus and other oral mucosa lesions of lichenoid characteristics. In the present paper, we carry out an updated review of the tests for, and the different characteristics of OLLC, which may aid the diagnosis. For this review, we made searches in the Pubmed® and Cochrane® databases. Among the literature we found several published papers, from which we have used review papers, case papers, cohort studies, case and control studies, and a meta-analysis study. After carrying out this review, we can conclude that the diagnosis of these lesions is still difficult and controversial. However, there are different aspects in the clinical presentation, pathological study and results obtained when replacing suspect materials, which, when taken together, may be useful when establishing the final diagnosis of OLLC.