spite of this it can withstand bite forces as high as 1,000 N many times a day during chewing. This resistance is due in part to the microstructure of enamel which contains enamel tufts that stabilize such fractures at the dentinoenamel junction. The configuration of the tooth also acts to reduce the tensile stresses that cause fractures during biting. Gastroesophageal reflux disease can also lead to enamel loss, as acid refluxes up the esophagus and into the mouth, occurring most during overnight sleep. Oral hygiene Because enamel is vulnerable to demineralization, prevention of tooth decay is the best way to maintain the health of teeth. Most countries have wide use of toothbrushes, which can reduce the number of dental biofilm and food particles on enamel. In isolated societies that do not have access to toothbrushes, it is common for those people to use other objects, such as sticks, to clean their teeth. In between two adjacent teeth, floss is used to wipe the enamel surfaces free of plaque and food particles to discourage bacterial growth. Although neither floss nor toothbrushes can penetrate the deep grooves and pits of enamel, good general oral-health habits can usually prevent enough bacterial growth to keep tooth decay from starting. Structural integrity of the enamel is genetic, and so is its predisposition to demineralization or attack from bacteria. Fluoride remineralization Fluoride catalyzes the diffusion of calcium and phosphate into the tooth surface, which in turn remineralizes the crystalline structures in a dental cavity. The remineralized tooth surfaces contain fluoridated hydroxyapatite and fluorapatite, which resist acid attack much better than the original tooth did. Fluoride therapy is used to help prevent dental decay. Fluoride ions, as an antimicrobial, may activate bacterial genes associated with fluoride riboswitches. The combination of fluoride ions and QAS (quaternary ammonium salts) was found to have a stronger antimicrobial effect on many oral bacteria associated with dental decay, including S. mutans. Fluoride in drinking water Most dental professionals and organizations agree that the inclusion of fluoride in public water has been one of the most effective methods of decreasing the prevalence of tooth decay. Fluoride can be found in many locations naturally, such as the ocean and other water sources. The recommended dosage of fluoride in drinking water does not depend on air temperature. Some groups have spoken out against fluoridated drinking water, for reasons such as the neurotoxicity of fluoride or