う蝕
Dental caries is a localized disease in which susceptible tooth structure is broken down by bacteria that are able to ferment carbohydrates into acid. Although it has not been extensively studied, researchers speculate that individuals fed by tube may be less prone to the development of caries as they are not exposed to carbohydrates orally. Examination of dental plaque from tube-fed individuals found that it contained fewer caries-associated microorganisms (lactobacilli and streptococcus) and had reduced ability to produce acids, suggesting an overall weaker ability to cause caries. Further, studies with animal subjects found that tube-feeding was not associated with tooth decay, even when combined with reduced salivation. Thus, tube-feeding alone does not necessarily directly promote the development of caries.