RESUMO
Numerous substances may have an adverse influence on the oral region by virtue of their potentially harmful effects. Dental practitioners are often the first to see these effects in the head and neck region. Knowledge of the damaging consequences of agents such as alcohol, tobacco, areca nut, medications, alcohol-containing mouthwashes, dental devices and materials can assist the practitioners in clinical decision-making and accurate diagnosis of associated lesions. More importantly, timely diagnosis and prompt reporting of such harmful effects improve the quality of care. Such knowledge may also help in patient's education for the avoidance of associated adverse effects (AEs). Consequently, a thorough acquaintance of AEs will consolidate the distinct role of medical and oral health practitioners in safeguarding the patients' oral and systemic well-being. This article was planned to review the harmful consequences of specific substances on the oral health. Traditionally, the emphasis of review articles has been on reviewing the harmful effects of a single entity on oral health. This review is unique in the sense that it comprehensively and collectively focussed on the harmful effects on the oral health of addictive and illicit substances (alcohol, betel nut), medications, alcohol-containing mouthwashes, medications and dental materials.