Halitosis - Foul Smell From Your Mouth
From Wikipedia, the free encyclopedia

Halitosis (medical term, first coined by the Listerine company in 1921), oral malodour (scientific term), breath odour, or most commonly bad breath are terms used to describe noticeably unpleasant odours exhaled 
in breathing.

Transient bad breath is a very common temporary condition caused by such things as oral dryness, stress, hunger (ketosis), eating certain foods such as garlic and onions, smoking, and poor oral hygiene. Morning breath is a typical example of transient bad breath. Chronic bad breath is a more serious and persistent condition affecting up to 25% of the population in varying degrees. It can negatively impact the individual's personal and business relationships, leading to poor self-esteem and increased stress. This condition is usually caused by persistent overpopulation of certain types of oral bacteria, primarily streptococcus mutans, and requires specialised treatment. Xerostomia (dry mouth syndrome) will increase bad breath problems. Fetor hepaticus is a type of bad breath caused by chronic liver failure. It has been said to resemble "the smell of a freshly opened corpse."

Though the causes of breath odour are not entirely understood, most unpleasant odors are known to arise from food debris trapped in the mouth which is processed by normal mouth flora; there are over 400 types of bacteria found in the average mouth. Several dozen of these can cause trouble when allowed to flourish or are genetically disposed to overpopulate. Large quantities of these naturally-occurring bacteria are often found on the posterior of the tongue, where they are undisturbed by normal activity. The rough surface of the tongue dorsum provides an ideal habitat for anaerobic bacteria, which flourish under a continually-forming tongue coating of food debris, dead cells, and hundreds of thousands of bacteria, living and dead. When left on the tongue, the anaerobic respiration of such bacteria can yield either the putrescent smell of polyamines, or the "rotten egg" smell of volatile sulfur compounds (VSCs) such as hydrogen sulfide, methyl mercaptan and dimethyl sulfide, depending on the bacteria type. It is generally these compounds which, when mixed with mouth air and exhaled, produce unpleasant breath.
Other causes of chronic bad breath may be periodontitis (gum disease), helminthiasis (intestinal parasitic infections), diabetes, kidney failure, sinusitis, tonsilloliths, gastroesophageal reflux disorder (GERD), trimethylaminuria (TMAU), hormonal changes, and a wide variety of prescription drugs (especially when taken on a longterm basis).

One's own breath odour is often undetectable due to habituation, although many people will have an accompanying bad taste (metallic, sour, fecal, etc) depending on oral dryness and the degree of breath odour. 
A somewhat effective home method to determine the presence of bad breath is to lick the back of the wrist, let the saliva dry for a minute or two, and smell the result. Another way would be to lightly scrape the posterior of the tongue with an inverted spoon or a piece of dental floss, and to smell the dried residue. A spouse, family member, or close friend may be willing to smell one's breath and provide honest feedback. Highly reliable home tests are now available which use a chemical reaction to test for the presence of polyamines and sulfur compounds on tongue swabs. Remember that breath odour changes in intensity throughout the day depending on many factors, so test several times.
If bad breath is persistent, and all other medical and dental factors have been ruled out, specialised testing and treatment is required.
Hundreds of dental offices and breath clinics now use a portable sulfide monitor called the Halimeter to test for levels of sulfur emissions (specifically, hydrogen sulfide) in the mouth air. When used properly this device can be very effective at determining levels of certain VSC-producing bacteria. However, it has drawbacks in clinical applications. For example, other common sulfides (such as mercaptan) are not recorded as easily and can be misrepresented in test results. Certain foods such as garlic and onions produce sulfur in the breath for as long as 48 hours and can result in false readings. The Halimeter is also very sensitive to alcohol, so one should avoid drinking alcohol or using alcohol-containing mouthwashes for at least 12 hours prior to being tested. This analog machine loses sensitivity over time and requires periodic recalibration to remain accurate.
New technology is now appearing in the form of portable gas chromatography machines such as the OralChroma, which is specifically designed to digitally measure molecular levels of the three major VSCs in a sample of mouth air (hydrogen sulfide, methyl mercaptan, and dimethyl sulfide). It is extremely accurate and produces visual results in graph form via computer interface.
Microbiological testing of swab samples of teeth and tongue residue remains the most accurate method of determining the specific bacterial causes of oral malodour.
Home Care

Using commercial breath-freshening mouthwashes, mints, or lozenges gives only temporary relief at best, since these products only mask mouth odours for a few minutes. Rinses containing antibacterials such as chlorhexidine, zinc gluconate, or chlorine dioxide may provide better control depending on the individual. Avoid alcohol-containing rinses, since alcohol is a drying agent and will worsen the problem.
Bad breath may be temporarily reduced by using a hydrogen peroxide rinse. Hydrogen peroxide at a concentration of 1.5% can be taken as an oral antiseptic by gargling 10 ml, about two teaspoons. Hydrogen peroxide is commonly available at a concentration of 3% and should be diluted to 1.5% by mixing it with an equal volume of water. Hydrogen peroxide is a powerful oxidizer which kills most bacteria, including useful aerobic bacteria.
The most effective products are generally not available in drugstores, but can be found on the internet. High-quality home breath tests and antibacterial rinses, spritzes, toothpastes, gums, mints, and tongue gels tend to be higher in price, like any premium product; but unlike the well-known inexpensive brand names, they do a much better job of controlling persistent breath problems. In the case of internet shopping for breath products, two caveats apply: the consumer must do extra research to make sure the vendor can be trusted (look for established halitosis clinics or dental supply companies); and remember that without professional assessment to guide you, there will be a certain amount of trial-and-error involved in finding the best solution for your problem.
Brushing after meals and flossing at least once daily is necessary to remove rotting food debris from between the teeth, especially at the gumline. Gently cleaning the tongue surface twice daily with a tonguebrush, tongue scraper, or tongue cleaner will reduce this primary source of breath odour. An inverted teaspoon is also effective; a toothbrush less so, as the size and angle of the head do not allow it to reach as far as necessary. Be careful to avoid scraping the V-shaped row of taste buds found at the extreme back of the tongue. Brushing a small amount of antibacterial mouth rinse or tongue gel onto the tongue surface will further inhibit bacterial action.
Since dry mouth can increase bacterial buildup and cause or worsen bad breath, chewing sugarless gum can help with the production of saliva, and thereby help to reduce bad breath. Some gums, toothpastes, sprays, and gels which combat dry mouth for several hours have recently been marketed over the counter. Maintain water levels in the body by drinking several glasses of water a day. Adding lemon juice to your water is refreshing and also beneficial. Parsley is a natural breath freshener when chewed slowly, and is easy to grow at home.
Some studies have shown that eating yogurt, drinking green tea, or chewing cinnamon or sugarless cinnamon gum can reduce bad breath.
How to Treat

1. Visit your dentist at least every six months for cleanings and checkups to keep your mouth free of plaque buildup and other problems that may lead to bad breath.
2. Watch your consumption of foods such as alcohol, coffee (both caffeinated and decaffeinated), dense proteins (such as those found in dairy and meat products), garlic and onions, and sugars. These are all bad-breath offenders.
3. Try to breathe through your nose. Breathing through your mouth can lead to having a dry mouth, which creates a breeding ground for odor-causing bacteria.
4. Keep a regular log of your eating habits and medications, as these can cause bad breath. Share the log with your dentist.
5. Brush your teeth and tongue twice a day to remove food particles and plaque, and floss between teeth once a day, preferably in the evening after you eat.
6. Try using a fluoride mouth rinse with antiseptic ingredients and a pleasant mint flavor. This helps to protect your teeth, and the flavor masks odor problems.
7. Consider internal breath fresheners'such as over-the-counter pills you take before or after a meal to aid the prevention of malodorous breath'or go the natural route and munch on some parsley after a meal.
Tips and Warnings:

Keep mints and gum on hand (or better yet, a toothbrush and toothpaste) for meals that include ingredients such as garlic and onions.
If bad breath persists, check with your dentist. Bad breath might be a warning sign of other health problems.
If you wear removable dentures, take them out at night, and clean them before you put them on again in the morning.
Tobacco users often suffer from bad breath and other mouth-related problems.
If symptoms persist or if you have specific medical conditions or concerns, we recommend you contact a physician. This information is not intended as a substitute for professional medical advice or treatment.