Physiological halitosis, such as morning bad breath, is caused by stagnant saliva and the putrefaction of trapped food particles and desquamated epithelial cells by the accumulation of bacteria on the back of the tongue, clinically recognized as coated tongue and decreased frequent fluid intake.
Normally, bad breath or halitosis is caused by certain foods or ingested substances, such as garlic and alcohol; by tooth decay or other dental disease and by the fermentation of food particles in the mouth. The latter is favored during sleep, since saliva production plummets while we sleep. Certain bacteria, such asStreptococcus mutans, take advantage of this circumstance to thicken the dental plaque, which, when solidifying, forms tartar. In addition, other microorganisms anaerobically decompose food debris trapped between the teeth. Bad morning breath can also be aggravated by gases that are reabsorbed from the colon and released through the lung surface when breathing.
Intraoral conditions are the cause of 80% of halitosis cases. Periodontal infections are characterized by a tremendous increase in negative bacteria that produce volatile sulfur compounds (VSC). The association between the anaerobic bacteria that produce VSC and halitosis has been well documented. The most important VSCs are hydrogen sulfide (H2S), methyl mercaptan, and dimethyl sulfide. The back of the tongue is the largest reservoir of bacteria as a source of smelly gases. Diamines such as putrescine and cadaverine are also responsible for oral odor.
Odontogenic infections include retention of food debris in deep carious lesions and large interdental areas, malignant teeth, defective restorations, exposed necrotic pulp, excessive use of acrylic dentures at night, infection of wounds at the extraction site, and poorly fitting dentures . The absence of saliva or hypofunction causes an increase in the gram-negative microbial load, which increases VSC, a known cause of malodour. Various mucosal lesions such as syphilis, tuberculosis, stomatitis, intraoral neoplasia, and peri-implantitis allow the colonization of microorganisms that release a large number of malodorous compounds.
Reference:
Uditi Kapoor,1 Gaurav Sharma,2 Manish Juneja,3 and Archna Nagpal. ‘Halitosis: Current concepts on etiology, diagnosis and management’ (2016) European Journal of Dentistry. doi: 10.4103/1305-7456.178294
