The causes of halitosis / bad breath

The causes of halitosis / bad breath

Halitosis is an oral health problem mainly caused by excessive amount of volatile sulfur compounds (thiols) that give breath its foul odor.
Food. Eating foods containing volatile sulfur compounds, like garlic and onions or some spices, is one of the most common causes of temporary halitosis. After these foods are digested, the sulfur compounds are absorbed into the bloodstream, they're carried to the lungs and exit from the body during exhale, causing bad breath.
Poor dental hygiene. Infrequent or improper brushing and flossing can leave food particles to decay inside the mouth. Their breakdown can cause a foul odor.
Dental problems. Periodontal disease or an abscess at the base of a tooth can be the causes of bad breath due to bacteria emitting hydrogen sulfur vapors.
Dry mouth (xerostomia) . Saliva helps cleanse and moisten the mouth. A dry mouth enables the accumulation of dead cells on tongue, gums and cheeks. These cells then decompose and cause odor. Even for a short period of time like sleep, the reduce of saliva flow makes the mouth dry causing what is called 'morning breath'.
Systemic diseases. Several illnesses can cause a distinctive breath odor. Kidney failure can cause a urine-like odor and diabetes may cause a fruity breath odor. Gastroesophageal reflux disease (GERD), liver failure or lung infections also can cause bad breath.
Systemic diseases and dry mouth are the most common causes of chronic halitosis.
Smoking is another bad breath cause, as it dries out the mouth and causes unpleasant mouth odor.
Dieting and fasting may cause unpleasant "fruity" breath due to ketosis or ketoacidosis.