Hospitalized patients and patients treated in Intensive Care Units (ICUs) are at high risk of contracting infectious diseases, mainly lung diseases resulting from respiratory pathogens found in the oral cavity due to deficient oral health maintenance. This problem could be avoided through preventive actions that require minimum intervention. The surface of the tooth, tongue and prostheses, as well as the ICU devices in contact with the patients' mouth, is large reservoirs for pathogens. Thus, cleaning the patients' mouth and removing infection foci may positively influence the quality of life and well-being of critically ill patients. The aim of the current study is to address the importance of having dentists in the health teams working in ICUs, as well as the activities performed, the necessary dental care and the relation between oral and systemic conditions. The study was approved by the Ethics Committee of the Catholic University of Brasília, Brazil, under protocol number CAAE 44578215.0.0000.0029. It was concluded that the lack of preventive measures, as well as the deficient oral cavity hygiene and clinical care in ICUs, are risk factors for the development of systemic diseases, mainly of diseases affecting the respiratory and cardiological tracts; therefore, the participation of dental surgeons in the interdisciplinary team is crucial to promote health in hospital environments.