The problem of bad breath has been around for thousands of years. It was written about in the Jewish Talmud, ancient Greek and Roman literature, and as early as 850 AD, Islamic literature offered some explanation for the origin of the teeth as well as "fetid breath". This age-old problem has numerous causes, but in an estimated 85% of the cases, the odor originates from the mouth. In the remainder of the cases, the nose, tonsils, and other ailments contribute to bad breath. Treatment for bad breath must address the source of the problem.
When the mouth is the cause of bad breath, food, oral habits and dental health should be examined first. Foods or beverages such as garlic, onions, and coffee, and habits such as smoking and chewing tobacco can contribute to bad breath. Dental problems such as broken teeth that trap food, infected teeth that abscess, or untreated periodontal (gum) disease are common causes of bad breath.
If the teeth and gums are healthy, the tongue is the most likely culprit. The back, top part of the tongue is a common and overlooked cause of bad breath. There is speculation that chronic postnasal drip that collects on the tongue becomes infiltrated with bacteria causing odor. Tongue brushing, or the use of a tongue-scraper can often alleviate this source. People who wear dentures without taking them out at night or cleaning them properly can have bad breath.
Excellent oral hygiene, brushing at least three times a day and flossing once a day is essential to fighting bad breath. It may be beneficial to chew sugarless gum and drink water throughout the day to moisten the mouth, which may reduce mouth odor. If odor persists after the teeth, gums, and tongue are clean and healthy, an antibiotic mouth rinse such as Peridex can be prescribed. If none of these measures succeed, a medical doctor should be consulted to explore other potential causes.
The nose is the second most common cause of bad breath. Sinus infections or polyps can cause bad breath, as well as children who insert foreign bodies into the nose. The tonsil may be a cause of bad breath in some people; especially if small tonsillar stones called tonsilloliths are formed and collect on the tongue.
Some other non-dental causes of bad breath include respiratory infections, kidney failure, some cancers, and other disorders. One rare disorder that causes a fishy mouth odor and taste is trimethylaminuria. The stomach and intestines are commonly thought to be a cause of bad breath, but this is not the case. The esophagus is normally closed, preventing odors from the stomach and intestines from reaching the mouth.
Bad breath is a sensitive topic that should be discussed with your dentist. Your dentist can help to discover the most likely cause and help to alleviate the problem.