Bacteria are difficult to pin down. First, they are incredibly small — microscopic. Second, they multiply extremely quickly. You start with one and in a short time have thousands! Therefore, the estimates on how many bacteria live inside our mouths vary greatly in number — from thousands in clean mouths to billions in every mouth. So talking about the total population of bacteria inside your mouth is essentially just an argument between dental scientists. Talking about how many different kinds of bacteria live there, however, is a completely different matter.
Thanks to advances in gene sequencing technology, scientists can take samples from human subjects and then determine exactly which species of bacteria are living in those samples. To date, one thousand different bacterial species have been identified from human subjects. And in one human mouth, anywhere from one hundred to two hundred different species are living together.
Identifying these bacteria and then making comparisons between the health of their human hosts is critical to understanding how certain bacteria affect our dental well-being. As a result, there are certain bacteria we know to be helpful to their host, and others that are essentially bacterial parasites!
The Rogues Gallery in Your Mouth
Streptococcus mutans – a major source of cavities, you don’t want this bacteria floating around your mouth!
Porphyromonas gingivalis — as its species name suggests, this one lives in your gums, or gingiva, irritating the tissues. As one research team put it, this bacterium “produces a myriad of virulence factors.”
Treponema denticola — like P. gingivalis, treponemes attack the gums, leading to severe gum disease. This bacterium actually interacts with others to “promote disease progression.” That’s one kind of cooperation you don’t need!
Prevotella intermedia — most gingival bacteria stay outside the gum tissues, where toothpaste and mouthwash can reach them. P. intermedia can avoid this danger by actually invading the epithelial cells that make up your gums.
In the face of these dangerous oral foes, the oral biome also features bacterial heroes that protect your oral health. Here are a couple:
Streptococcus salivarus K12 fights bad breath by beating its microcompetitors to oral resources. In the future, you may be able to buy lozenges loaded with this bacterium to improve your oral health.
Lactobacillus reuteri — this probiotic readily colonizes the human mouth. Studies suggest that it reduces the signs of gum disease. Like S. salivarus K12, it’s believed to simply do a better job at reproducing than its bacterial competitors, thus reducing the numbers of pathogenic bacteria.
Changing the oral biome by destroying harmful bacteria and promoting helpful species is an ongoing subject of scientific study. As we learn more about oral bacteria, it becomes obvious that some people are better off without mouthwash. If your particular bacterial colonies are helpful, it may be best to avoid aggressive anti-bacterial treatments! For more information and suggestions on how you can promote your personal oral health, please arrange a consultation with the dentists at the Sacramento Dentistry Group.