The most common use of mouthwash is commercial antiseptics, which are used at home as part of an oral hygiene routine. Some manufacturers of mouthwash state that antiseptic and anti-plaque mouth rinse kill the bacterial plaque that causes cavities, gingivitis, and bad breath.Anti-cavity mouth rinse uses fluoride to protect against tooth decay.hlorhexidine mouthwash alone is unable to prevent plaque, so it is not a substitute for regular toothbrushing and flossing. In the short term, if toothbrushing is impossible due to pain, as may occur in primary herpetic gingivostomatitis, chlorhexidine is used as temporary substitute for other oral hygiene measures.