Bad breath, or halitosis, is familiar to many people. Although precise epidemiological data are missing, some studies have suggested that bad breath may rank only behind dental cavities and periodontal diseases as the cause of patients' visits to the dentist.
The root cause behind bad breath can range from banal – poor oral hygiene after meals – to potentially life-threatening –complications from diabetes and kidney failure.
In the case of diabetic ketoacidosis, the body cannot properly breakdown and use glucose as an energy source, so it opts to breakdown body fat instead. A byproduct of breaking down fat is ketones, which can result in sweet, fruity breath if the disease is not addressed and the chemicals continue to build up in the blood and urine, according to the National Institutes of Health. Although it may sound more pleasant than conventional bad breath, diabetic ketoacidosis can become a serious problem if unaddressed, because ketones are poisonous at high levels.
Late-stage liver failure can also cause bad breath. Also known as "Fetor hepaticus", the sweet, musty aroma is cause by dimethyl sulfide, not ketones. Because of this, breath analysis could potentially be used as a diagnostic tool for detecting liver pathologies, according to an article published by Belgian researchers in the Journal of Chromatography B.
In addition, people with chronic liver failure may have breath that smells "fishy" or ammonia-like, according to the NIH. Known as "uremic fetor", this is caused by the high concentration of urea in the saliva and its subsequent breakdown to ammonia.
Treatments for bad breath usually involve either improving oral hygiene or targeting the underlying health problems.
Bad breath caused by the overgrowth of bacteria on the surface of the tongue can be successfully treated by a regimen that includes tongue brushing and scraping, according to a review published in the International Journal of Dental Hygiene.
In addition, gum disease can cause the gums to pull away from the teeth, according to the Mayo Clinic, leaving behind pockets where bacteria can settle in and replicate. Professional cleaning and mouth rinses can reach into these areas and eliminate bacterial growth.