Bacteria and Bad Breath

Scientists now know that bacteria and bad breath are intimately linked. It’s usually bacteria, in fact, that produce the very unpleasant odor we all associate with halitosis. What’s not so clear is why the bacteria cause problems in some people’s mouths but not in others: our mouths are full of microorganisms—everyone has millions of them—including bacteria, yeasts, sometimes even protozoa, and in most mouths, they cause no problem at all. Many of the organisms living in our mouths are actually beneficial: among other things, they compete with more harmful organisms that might otherwise cause infection. The ones that produce the bad smell are predominantly anaerobes.

Get too many anaerobes and bad breath will shortly follow. Anaerobes live in the absence of oxygen—some can tolerate a little oxygen while others are exquisitely sensitive to it and die quickly in its presence. When anaerobes metabolize proteins for food, they produce volatile sulfur compounds as a byproduct—gaseous sulfur containing molecules that smell awful. We’ve run into this kind of smell in nature: it’s the smell of rotten eggs, or of organic material rotting in wet oxygen depleted conditions. It explains the link between bacteria and bad breath.

Most people only have a few anaerobes living in the mouth. They exist in small airless locations, like the tight spaces between the teeth, in little pockets in the gums, and in the many grooves on the surface of the tongue, particularly at the back of the mouth. Have just a few anaerobes and bad breath is not a problem; have a lot and the picture changes. This explains why people with decaying teeth and gum disease tend to have trouble—more pockets and spaces available for anaerobes to multiply in, tissues breaking down and providing food for bacteria and bad breath is the inevitable result.

Understanding the relationship between anaerobes and bad breath suggests ways to control it. Keep your teeth and gums in good health; brush and floss regularly to remove food particles, prevent tartar, and clear away any accumulation of organic debris and bacterial growth; brush the tongue, taking care to brush the back of the tongue, a known site for bacteria and bad breath; have oral problems evaluated and treated by a medical professional. For persistent bad breath, choose commercial products that are formulated to reduce the troublesome bacteria through physical removal or by inhibiting growth and survival.

Fluoride and Bad Breath

Many mouthwashes and toothpastes contain fluoride, but is there any connection between fluoride and bad breath? There are probably two reasons that manufacturers add fluoride to mouthwashes: it is believed to prevent tooth decay, which is associated with bad breath, and it is believed to inhibit the production of acids by oral bacteria, the producers of foul smelling compounds that are expelled on the breath. However, there is much controversy about the addition of fluoride to drinking water, toothpastes, mouthwashes and other products. It is likely that it is not doing much good there and it may actually be doing harm.

Fluoride has its maximum effect in preventing tooth decay when it actually comes in contact with tooth enamel, so it makes sense to put fluoride in mouthwash and toothpastes, which are applied directly to the teeth. The effect on breath is rather indirect: bacteria present in dental plaque produce acids while they are breaking down ingested sugar, and this acid, in turn wears down the tooth enamel by demineralizing it (dissolving out the calcium and phosphate minerals that make enamel so tough). Saliva then neutralizes the acid and the minerals are reabsorbed. When fluoride is present, remineralization is more efficient and is believed to produce a stronger enamel. When remineralization does not replace all of the lost minerals, cavities appear. Some of the acid producing bacteria also produce volatile sulfur compounds, which cause the offensive odor of bad breath - they proliferate when the teeth and gums are unhealthy, so the idea is to prevent tooth decay with flouride and bad breath will be avoided as well.

Unfortunately, its not that easy. For one thing, fluoride is a toxin at high levels, so putting fluoride in mouthwash adds to an already high intake in people who drink fluoridated water and brush with fluoride containing toothpaste. The major risk comes when you swallow the products, so take care to spit out mouthwash and rinse to minimize ingestion. Swallowing too much fluoride, once thought to be harmless, is now associated with a number of health problems including weak bones, a form a bone cancer, damage to the teeth, and several other conditions. The link between fluoride and bad breath is tenuous at best - if your teeth are healthy, there's no reason to use more fluoride. Look for a mouth wash that doesn't contain it.

Remember that most of the bacteria that produce volatile sulfur compounds live on the tongue, down in the tiny crevices between the taste buds, protected from saliva and oxygen by a layer of mucus. Others live in creases in the gums and cheeks, in pockets around the teeth and between the teeth. When it comes to these bacteria, there is no point at all in putting fluoride in mouthwash - the ingredient neither harms nor helps them. The best approach is to try to lower their numbers by other means, such as inhibiting their growth or removing them from the mouth. Given the minimal benefit and the possibility of harm, fluoride and bad breath is not a relationship anyone should be focusing on.