Bad Breath

• Food. The breakdown of food particles in and around your teeth can cause a foul odor. Eating foods containing volatile oils is another source of bad breath. Onions and garlic are the best-known examples, but other vegetables and spices also can cause bad breath. After these foods are digested and the pungent oils are absorbed into your bloodstream, they're carried to your lungs and are given off in your breath until the food is eliminated from your body. Onions and garlic can cause bad breath for as long as 72 hours after you've eaten them.
• Dental problems. Poor dental hygiene and periodontal disease can be a source of bad breath. If you don't brush and floss daily, food particles remain in your mouth, collecting bacteria and emitting hydrogen sulfide vapors. A colorless, sticky film of bacteria (plaque) forms on your teeth.
• If not brushed away, plaque can irritate your gums (gingivitis) and cause tooth decay. Eventually, plaque-filled pockets can form between your teeth and gums (periodontitis), worsening this problem — and your breath. Dentures that aren't cleaned regularly or don't fit properly also can harbor odor-causing bacteria and food particles.
• Dry mouth. Saliva helps cleanse and moisten your mouth. A dry mouth enables dead cells to accumulate on your tongue, gums and cheeks. These cells then decompose and cause odor. Dry mouth naturally occurs during sleep. It's what causes "morning breath." Dry mouth is even more of a problem if you sleep with your mouth open. Some medications as well as smoking can lead to a chronic dry mouth, as can a problem with your salivary glands.
• Diseases. Chronic lung infections and lung abscesses can produce very foul-smelling breath. Other illnesses, such as some cancers and certain metabolic disorders, can cause a distinctive breath odor. Kidney failure can cause a urine-like odor, and liver failure may cause an odor described as "fishy." People with uncontrolled diabetes often have a fruity breath odor. Chronic reflux of stomach acids from your stomach (gastroesophageal reflux disease, or GERD) also has been associated with bad breath.
• Mouth, nose and throat conditions. Bad breath is also associated with sinus infections because nasal discharge from your sinuses into the back of your throat can cause mouth odor. A child with bad breath may have a foreign object lodged in his or her nose. A bean or small item stuck in the nose can cause persistent nasal discharge and a foul odor. Throat infections can cause bad breath until they clear. Bronchitis and other upper respiratory infections in which you cough up odorous sputum are other sources of bad breath.
• Tobacco products. Smoking dries out your mouth and causes its own unpleasant mouth odor. Tobacco users are also more likely to have periodontal disease, an additional source of bad breath.
• Severe dieting. Dieters may develop unpleasant "fruity" breath from ketoacidosis, the breakdown of chemicals during fasting.

Treatments and drugs

Treatment for bad breath can vary, depending on the cause. If your bad breath is found to be caused by an underlying health condition, your dentist will likely attempt to help you better control that condition. Other dental measures may include certain mouthwashes and toothpastes or treatment of dental disease.

• Mouth rinses and toothpastes. If your bad breath is due to a buildup of bacteria (plaque) on your teeth, your dentist may recommend a mouth rinse that kills the bacteria. Research shows that those containing cetylpyridinium chloride and those with chlorhexidine can prevent production of odors that cause bad breath. Other active ingredients, such as chlorine dioxide and zinc, are good at neutralizing odor-causing bacterial byproducts. Your dentist may also recommend a toothpaste that contains an antibacterial agent to kill the bacteria that cause plaque buildup.
• Treatment of dental disease. If your dentist discovers that you have gum disease, you may be referred to a periodontist (gum specialist). Gum disease can cause the gums to pull away from the teeth, leaving deep pockets that accumulate odor-causing bacteria. Sometimes these bacteria can be removed only by professional cleaning. Your dentist might also recommend replacing faulty tooth restorations, which can be a breeding ground for bacteria.

Lifestyle remedies

Try the following steps to improve or prevent bad breath:

• Brush your teeth after you eat. Keep a toothbrush at work to brush after eating. Be sure to brush at least twice a day, especially after meals. Toothpaste with antibacterial properties has been shown to reduce bad breath odors for up to 12 hours.
• Floss at least once a day. Proper flossing removes food particles and plaque from between your teeth.
• Brush your tongue. A tongue scraper is more effective than a brush for reducing odors that originate from the tongue. Another option is to use a toothbrush with a built-in tongue cleaner on the back. These brushes reportedly work just as well as scrapers.
• Clean your dentures well. If you wear a bridge or a partial or complete denture, clean it thoroughly at least once a day or as directed by your dentist.
• Drink plenty of water. To keep your mouth moist, be sure to drink plenty of water — not coffee, soft drinks or alcohol, which can lead to a drier mouth. Chewing gum (preferably sugarless) or sucking on candy (preferably sugarless) also stimulates saliva, washing away food particles and bacteria. If you have chronic dry mouth, your dentist or doctor may additionally prescribe an artificial saliva preparation or an oral medication that stimulates the flow of saliva.
• Adjust your diet. Decrease alcohol and coffee intake and avoid other food and beverages that can precipitate bad breath. Eating fibrous foods can help.
• Use a fairly new toothbrush. Change your toothbrush every three to four months, and choose a soft-bristled toothbrush.
• Schedule regular dental checkups. At least twice a year, see your dentist to have your teeth or dentures examined and cleaned.

References:

http://articles.mercola.com/bad-breath.aspx

http://www.medicinenet.com/bad_breath/article.htm

http://www.colgate.com/en/us/oc/oral-health/conditions/bad-breath/article/ada-03-what-causes-bad-breath

http://www.nhs.uk/Conditions/bad-breath/Pages/causes.aspx

http://patient.info/health/bad-breath-halitosis