Studies have shown that about 85% of patients suffering from halitosis have an oral condition as the source. If a person has healthy teeth and gums (i.e. no cavities, periodontitis, or abscesses), the next most common source of oral malodor is the tongue. Bacteria which produce volatile sulfur compounds (VSCs) have been found to congregate on the tongue, especially the posterior one third. Saliva from nearby glands drips down on the posterior region of the tongue, which is full of irregularities where bacteria love to hide. The anaerobic bacteria (bacteria which thrive without oxygen) break down specific components (amino acids) of the saliva, creating certain gases or VSCs. These VSCs have been implicated as a major contributing factor to halitosis. Other contributing oral factors include inflammatory conditions, oral cancer, oral candidiasis, and xerostomia (dry mouth).

While the oral cavity is by far the most common source of bad breath, systemic conditions can also be responsible for this condition. Nasal and sinus problems, including foreign bodies inserted in the nose and neglected for a period of time, can be a cause. Repetitive tonsillar infections, infections of the oropharynx, pulmonary diseases (such as bronchitis and pneumonia), and gastrointestinal problems are all possible contributing factors. Certain systemic diseases produce particular odors. A few of these relationships include liver failure producing a rotten egg smell, diabetes producing a sweet smell, intestinal dysfunction producing heavy sour breath, and scarlet or typhoid fever producing a musty smell.

Detection

While most of the population has transient halitosis, chronic malodor is less common. Regardless of the type of halitosis, proper diagnosis is important. The difficulty in determining whether an individual has halitosis and its possible cause(s) arises because there are no convenient methods to measure this condition. Some self-monitoring tests and in-office tests are available to aid in the diagnosis, although they are either awkward or still need research to ensure their viability.

Self-monitoring tests generally involve obtaining feedback from a spouse or friend (an odor judge). Individuals may have difficulty detecting halitosis themselves because the brain has the ability to suppress odors stemming from ourselves. While procuring an odor judge may be embarrassing, it is the best method for at-home breath testing. If the odor judge does not wish to smell the patient's breath directly, the patient can scrape the posterior region of the tongue with a spoon or place saliva on the wrist by licking it. The spoon or wrist can then be smelled and assessed by the odor judge. The spoon test is better in case the saliva is not a good carrier of the potential odorant. There is also a home microbial test which is comprised of cotton-tipped applicators and test tubes containing a specific medium. After the applicators are placed on the tongue, they are inserted in the test tubes. If the color in the test tube changes within a certain time period, this is an indication that you have chronic bad breath.

In-office testing can include odor judge testing, microbial and fungal testing, the salivary incubation test, volatile sulfur detection testing, and, in the future, artificial noses. Among other problems, the current tests lack specificity, i.e. it is difficult to determine either the existence or the cause of chronic halitosis. The most recent machine on the market for detecting halitosis, a portable sulfide monitor, also has its proponents and critics. The machine is designed to measure sulfur content in the breath, but it can be inaccurate. At this point, the machine is better for monitoring a patient's progress than in obtaining an initial diagnosis. Most dental offices do not have the capability yet to perform these tests.

Treatments

One of the easiest and most efficient treatments for halitosis is mechanical debridement. This means thorough, regular flossing and brushing of your teeth and your tongue. A tongue scraper can be very helpful as well. When using a tongue scraper, it is best to clean as far back on the tongue as possible, starting from the back and moving toward the front. This scraping motion is done several times in row. Other management tools include antibiotics, nasal mucous control methods, avoidance of certain foods and medications, salivary substitutes, and management of systemic diseases. One of the most potentially promising and lucrative areas of bad breath control is the development of various oral rinses.

Effective oral rinses must eliminate the problematic bacteria while maintaining the balance of normal bacteria in the oral environment. The assorted types of rinses being developed and marketed contain quaternary ammonium, zinc, chlorhexidine (already in use to help treat periodontitis), chlorine dioxide, or triclosan. Chlorhexidine and chlorine dioxide rinses have received the most press lately. Because chlorhexidine is such a strong antimicrobial rinse, it is advised to only use this type of rinse as a short-term adjunct for treatment. At present, chlorine dioxide can be used on a long-term basis, although some researchers do question its safety. In lab experiments, chlorine dioxide has been shown to be effective by breaking the sulfide bonds in VSCs, but this finding has not yet been substantiated using live subjects.

Currently, many of these rinses provide limited effectiveness in the treatment of chronic halitosis. Regular dental care and proper oral hygiene including tongue cleaning are the most effective. The detection and treatment of halitosis is a relatively new aspect of dentistry. The future is sure to bring better diagnostic techniques and treatments.