Dry mouth: Xerostomia, the medical term for dry mouth, provides a perfect environment for anaerobic bacteria reproduction. Long periods of speaking, smoking, drinking alcohol, and snoring are a few common underlying causes. Most people experience foul breath in the morning due to lack of saliva production while they sleep. For healthy individuals, food odors are temporary and normal salivary flow will eliminate them within several minutes. However, those who suffer from dry mouth and lack of saliva find that even minor food odors may lead to long-term issues.
Foods: Halitosis can be exacerbated by certain foods such as onions and garlic because they contain smelly sulfur compounds, while dairy, meat, and fish contain dense proteins which are used as a food source by the anaerobic, sulfur-producing bacteria. Refined and processed sugars also provide a food source for bacteria. Coffee and juices can contribute to this problem because they are acidic and provide these bacteria with an ideal breeding environment.
Poor dental hygiene: Inadequate oral care causes bacterial buildup on the teeth and gums. Teeth cannot shed their surfaces the way skin can, so microorganisms can easily attach to the teeth and remain there for extended periods. If they are not continuously removed by adequate brushing, these bacteria develop into something called biofilm, commonly known as dental plaque. When plaque is allowed to accumulate near the gumline, it will harden and begin destroying teeth and gum tissues due to intense bacterial activity. This leads to gum disease such as gingivitis and periodontitis, which enable proteins from bleeding gums and diseased oral tissue to fuel odor-causing bacteria. Tooth decay and poorly fitting or dirty dentures can also contribute to this problem.
Illness and disease: According to studies, an estimated 10% of all halitosis cases are caused by certain illnesses. Individuals who suffer from diabetes, lung disease, kidney disease, cancer, liver disease, respiratory tract infections, or metabolic disorders often experience chronic foul breath due to dry mouth. Sinusitis, pneumonia, bronchitis, postnasal drip, and polyps affect the airways and may also contribute to the problem. Other common illnesses associated with bad breath include nasal odor and tonsil stones, yeast infections of the mouth, and gum disease. Certain drugs such as antidepressants, high blood pressure medications, and antihistamines can factor into dry mouth because they reduce saliva production.