Bad Breath
Bad breath occurs when noticeably unpleasant odors are exhaled in breathing. Halitosis is estimated to be the third most frequent reason for seeking dental aid, following tooth decay and periodontal disease.
 
 
 

In most cases (85–90%), bad breath originates in the mouth itself. The intensity of bad breath differs during the day, due to eating certain foods (such as garlic, onions, meat, fish, and cheese), obesity, smoking, and alcohol consumption. Since the mouth is exposed to less oxygen and is inactive during the night, the odor is usually worse upon awakening ("morning breath"). Bad breath may be transient, often disappearing following eating, brushing one's teeth, flossing, or rinsing with specialized mouthwash.

Methods used against bad breath, such as mints, mouth sprays, mouthwash or gum, may only temporarily mask the odors created by the bacteria on the tongue, but cannot cure bad breath because they do not remove the source of the bad breath. In order to prevent the production of the sulfur-containing compounds mentioned above, the bacteria on the tongue must be removed, as must the decaying food debris present on the rear areas of the tongue. The most widely-known reason to clean the tongue is for the control of bad breath. Most people who clean their tongue use a tongue cleaner (tongue scraper), or a toothbrush.