micro-fissures and cracks in the surface of dentures to aid their retention. Dentures may therefore become covered in a biofilm, and act as reservoirs of infection, continually re-infecting the mucosa. For this reason, disinfecting the denture is a vital part of treatment of oral candidiasis in persons who wear dentures, as well as correcting other factors like inadequate lower facial height and fit of the dentures. Dry mouth Both the quantity and quality of saliva are important oral defenses against candida. Decreased salivary flow rate or a change in the composition of saliva, collectively termed salivary hypofunction or hyposalivation is an important predisposing factor. Xerostomia is frequently listed as a cause of candidiasis, but xerostomia can be subjective or objective, i.e., a symptom present with or without actual changes in the saliva consistency or flow rate. Diet Malnutrition, whether by malabsorption, or poor diet, especially hematinic deficiencies (iron, vitamin B12, folic acid) can predispose to oral candidiasis, by causing diminished host defense and epithelial integrity. For example, iron deficiency anemia is thought to cause depressed cell-mediated immunity. Some sources state that deficiencies of vitamin A or pyridoxine are also linked. There is limited evidence that a diet high in carbohydrates predisposes to oral candidiasis. In vitro and studies show that Candidal growth, adhesion and biofilm formation is enhanced by the presence of carbohydrates such as glucose, galactose and sucrose. Smoking Smoking, especially heavy smoking, is an important predisposing factor but the reasons for this relationship are unknown. One hypothesis is that cigarette smoke contains nutritional factors for C. albicans, or that local epithelial alterations occur that facilitate colonization of candida species. Antibiotics Broad-spectrum antibiotics (e.g. tetracycline) eliminate the competing bacteria and disrupt the normally balanced ecology of oral microorganisms, which can cause antibiotic-induced candidiasis. Other factors Several other factors can contribute to infection, including endocrine disorders (e.g. diabetes when poorly controlled), and/or the presence of certain other mucosal lesions, especially those that cause hyperkeratosis and/or dysplasia (e.g. lichen planus). Such changes in the mucosa predispose it to secondary infection with candidiasis. Other physical mucosal alterations are sometimes associated with candida overgrowth, such as fissured tongue (rarely), tongue piercing, atopy, and/or hospitalization. Diagnosis The diagnosis can typically be made from the clinical appearance alone, but not always. As candidiasis can be variable in appearance, and present with white, red or combined white and red lesions, the differential diagnosis can be extensive.