Langerhans cell histiocytosis (LCH) is a rare disease, of unknown pathogenesis, characterized by intense and abnormal proliferation of bone marrow-derived histiocytes (Langerhans cells). It can present both local and systemic manifestations involving bone, skin and mucosal tissue, and internal organs. Three basic clinical forms develop: Letterer-Siwe disease (subacute or acute disseminated form), Hand-Schüller-Christian disease (disseminated chronic form) and eosinophilic granuloma (localized chronic form). LCH may manifest orally with single or multiple lesions of the alveolar or basal bone, ulcerated mucosal lesions accompanied by adenopathies and/or periodontal lesions, presenting gingival inflammation, bleeding, recession, necrosis, odontalgia, dental hypermobility and premature loss of teeth. The principal differential diagnoses include advanced periodontal disease or a periapical process of dental or periodontal origin. The odontologist plays a vital role in the diagnosis and multidisciplinary treatment of such patients, by performing routine examinations for periodic follow-up of the disease and its possible oral manifestations, bearing in mind that these may be the first or only signs of LCH.