RESUMEN
STATEMENT OF PROBLEM: Type IV hypersensitivity reactions (Type IV HR) are immune responses mediated by antigen-specific effector T cells. PURPOSE: The purpose of this clinical report and systematic review was to report the clinicopathological features of Type IV HR in the oral mucosa and to present a systematic literature review of case reports and case series of individuals with Type IV HR in the oral mucosa related to contact with dental materials. MATERIAL AND METHODS: The presented clinical lesions were melanotic macules with burning that affected the internal labial mucosa in contact with composite resin veneer crowns. Histopathological and immunohistochemical analysis of the lesion was performed. The systematic literature review was performed based on a search in 4 electronic databases (PubMed/MEDLINE, Scopus, Web of Science, and Ovid). RESULTS: Immunohistochemistry showed positivity for CD4, CD8, CD20, CD3, tryptase, and CD117. After conservative treatment, the patient reported improvement of symptoms, and a decrease in the number of inflammatory cells was verified. Twenty-one articles were included in the review. Unlike the present patient, the authors of all the articles recommended radical treatment with the removal of the dental material. CONCLUSIONS: Type IV HR in oral mucosa is rare, and the assessment of clinical and histopathological characteristics is essential to perform an accurate diagnosis and provide appropriate treatment.