Poor oral health is common among mentally ill people and is related to inadequate nutrition, poor self-care, substance abuse, and medication side effects. Poor oral hygiene is a significant problem because it results in dental pathology that has an adverse influence on the whole body. Compared with the general population, mentally ill patients are 3 times more likely to have their teeth removed. In a survey of mentally ill adults, 92% were found to have tooth decay—of which 23% were untreated and 40% smoked tobacco. Approximately 9% have periodontal disease, which most often occurs in those who smoke cigarettes.