Human body acts as a whole and this leads to an increased occurrence of oral manifestations during the onset and development of systemic diseases. Therefore, oral pathological manifestations play an important role in the diagnosis, prognosis and treatment of diseases with osteoarticular involvement. General pathology has a strong impact on oral health which in turn is influenced by systemic factors. Oral manifestations can be used for making an early diagnosis of a serious condition that can be cured with appropriate therapy. Oral lesions can be explained by pathological processes and correlated with systemic diseases. When oral symptoms and signs are present, the disease is already in an advanced stage, due to the fact that the oral cavity is usually affected by a generalized disease. The mouth is part of the digestive system, but it has various symptoms caused by diseases located in other regions. 98 patients with oral manifestations of diseases with osteoarticular involvement were followed up in a private dental clinic from Iasi over a period of 3 years between June 2013 and July 2016. 47 patients were male (47.95%) and 51 were female (52.05%), aged between 18 and 65 years old, with a peak incidence between the ages of 45 and 60. The complex structure of the oral cavity was thoroughly explored (lips, lip mucosa, the corners of the mouth, gingival labial sulcus, oral vestibule, the internal face of the cheeks, the outer surface of gums, the floor and the ceiling of the oral cavity or the hard and the soft palate). The health status of the body is reflected by the health of the oral mucosa, which can be seen as a marker of various systemic diseases.