う蝕
Dental caries is a dental biofilm-related oral disease associated with increased consumption of dietary sugar and fermentable carbohydrates. When dental biofilms remain on tooth surfaces, along with frequent exposure to sugars, acidogenic bacteria (members of dental biofilms) will metabolize the sugars to organic acids. Untreated dental caries is the most common disease affecting humans worldwide . Persistence of this acidic condition encourages the proliferation of acidogenic and aciduric bacteria as a result of their ability to survive at a low-pH environment. The low-pH environment in the biofilm matrix erodes the surface of the teeth and begins the "initiation" of the dental caries. "Streptococcus mutans" is a bacterium which is prevalent within the oral environment and is thought to be a vital microorganism that contributes to this initiation. "S. mutans" thrives in acidic conditions, becoming the main bacterium in cultures with permanently reduced pH . If the adherence of "S. mutans" to the surface of teeth or the physiological ability (acidogenity and aciduricity) of "S. mutans" in dental biofilms can be reduced or eliminated, the acidification potential of dental biofilms and later cavity formations can be decreased.