Bad breath is caused by a variety of factors. In most cases, it is caused by food remaining in the mouth—on the teeth, tongue, gums, and other structures—and collecting bacteria. Dead and dying bacterial cells release a sulfur compound that gives your breath an unpleasant odor.
Certain foods, such as garlic and onions, contribute to breath odor. Once the food is absorbed into the bloodstream, it is transferred to the lungs, where it is exhaled. Brushing, flossing and mouthwash only mask the odor. Dieters sometimes develop unpleasant breath from fasting. Periodontal (gum) disease often causes persistent bad breath or a bad taste in the mouth, and persistent bad breath may mean a sign that you have gum disease. Gum disease is caused by plaque - the sticky, often colorless, film of bacteria that constantly forms on teeth.
Dry mouth, or xerostomia, may also cause bad breath due to decreased salivary flow. Saliva cleans your mouth and removes particles that may cause odor. Tobacco products cause bad breath and stained teeth, they reduce your ability to taste foods, and they irritate your gum tissues. Bad breath may also be a sign that you have a serious health problem, such as a respiratory tract infection, chronic sinusitis, postnasal drip, chronic bronchitis, diabetes, gastrointestinal disturbance, or liver or kidney ailment.
Daily brushing and flossing, and regular professional cleanings will normally take care of unpleasant breath. And don't forget your often overlooked tongue as a culprit for bad breath. Bacterial plaque and food debris also can accumulate on the back of the tongue. The tongue's surface is extremely rough and bacteria can accumulate easily in the cracks and crevices. Controlling periodontal disease and maintaining good oral health helps to reduce bad breath. If the odor comes from gum disease, your dentist can either treat the disease or refer you to a periodontist, a specialist that treats gum tissues. Gum disease can cause gum tissues to pull away from the teeth and form pockets. When these pockets are deep, only a professional periodontal cleaning can remove the bacteria and plaque that accumulate.
Improperly cleaned dentures can also harbor odor-causing bacteria and food particles. If you wear removable dentures, take them out at night and clean them thoroughly before replacing them. If you have constant bad breath, make a list of the foods you eat and any medications you take. Some medications may contribute to bad breath. If your dentist determines that your mouth is healthy and that the odor is not oral in nature, you may be referred to your family physician or to a specialist to determine the cause of the odor and possible treatment.