Bad Breath and Bacteria

Bad breath and bacteria go hand in hand. Few people realize how many bacteria live in the human mouth. Scientists tell us that as many as seven hundred different species of bacteria can live in our mouths, with each individual playing host to perhaps one hundred species at any given time. This may not sound good, but in fact most of these bacteria are harmless, and some are even beneficial, protecting us from disease causing organisms that might move in if they had the opportunity. Only a handful of the species living in our mouths produce volatile sulfur compounds (VSC), the bad smelling gases in oral malodor.

The link between halitosis and VSC was worked out decades ago. Some anaerobic bacteria (anaerobic means living in the absence of oxygen) break down proteins in the mouth to obtain nutrients. In the process, they release sulfur compounds as a by-product. Studies show that in at least 85% of cases, bad breath and bacteria that obtain their food in this way are closely linked. Most cases involve one or more of four specific groups of bacteria.

Studies focused on bad breath and bacteria have revealed other things about a typical case of oral malodor. The bacteria can flourish anywhere in the mouth where they are not exposed to oxygen, but in the majority of cases, the culprits live in the grooves at the back of the tongue, shielded from oxygen by a tongue coating, or biofilm, and well supplied with a protein food source from food particles, dead oral cells, and sinus drainage. Other possible oral sources of halitosis and VSC include pockets in the gums, and the tonsillar crypts, both places where there is little air flow.

Once people understand the relationship between bad breath and bacteria, they are better able to deal with the problem. In the majority of cases, vigilance toward dental and oral hygiene, including regular scraping and cleaning of the tongue to remove tongue coating will make an immediate difference in the production of halitosis and VSC. Oral products that contain essential oils, zinc chloride, and cetylpyridium chloride have been studied and there is some evidence that they’re effective. Drinking plenty of water is also helpful as it not only rinses the mouth, but also encourages plentiful saliva production.

Source: Krespi, Yosef P., Mark G. Shrime, and Ashutosh Kacker. The relationship between oral malodor and volatile sulfur compound–producing bacteria. Otolaryngology–Head and Neck Surgery (2006) 135, 671-676.