1. Our oral microbiome and sugar’s role in tooth decay
particles - where science matters
  • Our oral microbiome and sugar’s role in tooth decay

    By Janna Fischer, 3M Storyteller

    young girl brushes her teeth

    • The bacterial diversity of our oral cavity – our oral microbiome – is equally as fascinating as the gut microbiome we hear so much about.

      It’s estimated that 500 species of bacteria are living in our mouths at any given time. Our mouths are continuously seeding our gastrointestinal tracts with bacteria. So how important is our oral health when it comes to our overall health? And what role does sugar play?

      According to recent findings, it seems to be much more important than we once thought.

      “For many years, we have been aware of some associations between oral diseases and certain systemic conditions, but the mechanisms were not very well understood,” says Carola Carrera Vidal, Ph.D., 3M Oral Care microbiologist and dentist. “Nowadays, we have a much better understanding of the association between an unbalanced microbiome and several oral and systemic conditions and diseases.”

      Microbiologists explain our mouths as complex ecosystems, teeming with an incredible number of microorganisms, including bacteria, yeast and viruses. A change in its delicate balance, like high exposure to sugar, can trigger dysbiosis – or microbial imbalance – and start the tooth decay process.

    Find out what’s being done around the world to tackle the devastating impact of tooth decay for disadvantaged children.

    • On a basic level, here’s what’s going on in our mouths throughout the day.

      Our mouths are in a constant battle of demineralization and remineralization. When we consume sugar, the bacteria in our mouths digest the sugar and produce acid, which weakens tooth enamel (demineralization). On the other hand, the minerals in our saliva – and the fluoride from toothpaste and water – help the weakened tooth enamel repair and strengthen itself (remineralization).

      One of the defining characteristics of these incredible bacterial ecosystems in our mouths? Their ability to form a biofilm.

      A biofilm is a thin, slimy film of bacteria that adheres to a surface. Although the term biofilm might be unfamiliar to many of us, the concept certainly isn’t – we encounter biofilms daily in our lives. They flourish upon moist or wet surfaces: Slippery rocks in a stream are coated with biofilm, and so is your dog’s water bowl and clogged drains. And one of the most common biofilms of all? Dental plaque – a thriving biofilm in our mouths.

      Several distinct surfaces inside our mouths develop biofilms, including our enamel (the hard, outer surface of our teeth), the roots of our teeth (when the gum has recessed), as well as our tongues, gums and cheeks.

      “It’s been found that the microbiomes of each of those biofilms are quite different from one another,” says Dr. Carrera. “The biofilm attaching to hard surfaces are referred to as dental plaque. The tooth is a non-shedding surface, so biofilms can accumulate in great quantities when oral hygiene is not properly conducted, or when too much sugar is introduced.”

    • Aaaahhh, sugar.

      We love it. And, given all the recent chatter about how it negatively affects our health, we also love to hate it. It’s been well known for decades that sugar is a leading risk factor for tooth decay, and that reducing its consumption as part of a healthy diet not only promotes better oral health, but may reduce diabetes, obesity and other non-communicable diseases.

      The microbiome model of tooth decay is described as an imbalance in the oral biofilm in which the bugs who produce the highest amounts of acid become predominant. Our mouths can be in a state of dynamic balance where these more harmful bugs are kept in check by their neighbors. But, when we eat sugar, it creates a feeding frenzy for the acid-producing bugs, which increases their population and allows them to outnumber their neighbors. This is what is called a biofilm in dysbiosis.

    Biofilms can accumulate when oral hygiene is not properly conducted.

    • Sugar is sneaky

      The “acid attacks” that happen in our mouths when we consume sugar significantly contribute to tooth decay. The biggest offenders to our teeth typically include soda, sports drinks, fruit juices and gummy, sticky and long-lasting sweets. But sugar hides in places we wouldn’t think to look, like barbecue and pasta sauces, fruit yogurt and even bread.

      The good news? Tooth decay is highly preventable. Some say it’s even up to 90 percent avoidable. Here’s how:

      Know the numbers

      The World Health Organization recommends adults and children reduce their daily intake of free sugars to less than 10 percent of their total energy intake. They also say that a further reduction to less than five percent or roughly 25 grams – or six teaspoons – per day would provide additional health benefits.

      But the average American’s sugar intake is upwards of 88 grams – or two teaspoons – per day. That’s almost four times as much as the WHO says is healthy.

      Drink fluoridated water

      Community water fluoridation is recommended by nearly all public health, medical and dental organizations. More than 70 years of scientific research has consistently shown that an optimal level of fluoride in community water is safe and effective in preventing tooth decay by at least 25 percent in both children and adults.

      Brush and floss daily

      Brushing with a fluoride toothpaste for at least two minutes twice a day is a proven way to keep your mouth healthy. When we brush with fluoride toothpaste, the fluoride is applied to the surface of our teeth, which provides a topical benefit and helps to remineralize our tooth enamel.

      And don’t forget to floss before bed, too. Flossing removes food debris and plaque that our toothbrushes sometimes can’t reach.

      Say hi to your dentist

      It really does pay to go to the dentist on a regular basis: Your dentist can check for problems that you may not see or feel, and many dental problems don't become visible or cause pain until they are in more advanced stages.

      Say thanks to your saliva

      Our saliva plays a huge role in the health of our mouths. It’s our mouth’s primary defense against tooth decay and maintains the health of the soft and hard tissues in the mouth, says the American Dental Association. It washes away food, neutralizes acids produced by bacteria and provides disease-fighting substances, offering first-line protection against microbial invasion or overgrowth that might lead to disease. If you have symptoms of dry mouth or hyposalivation, consult with your dentist.