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Can Green Tea a Day Keep the Dentist Away?

What would you say if your daily cup of green tea could protect your teeth from cavities? Various researchers have claimed that the tea plant commonly used in green tea, can kill the bad bacteria that cause cavities. However, this claim does not mean that you can throw your toothbrush and floss out the window—flossing regularly, brushing for two minutes twice daily and having a good diet are still the most important things you can do to prevent cavities.

Research shows that in moderation, green tea has no harmful side effects and can be beneficial for your teeth; however, this new realization requires more research to be 100% confident. Let’s see why. Before we can understand how green tea can prevent cavities, we need to find out what causes a cavity to develop on a tooth in the first place.

A hole in my tooth?! How?!

Let’s take your bike for example; have you ever left it sitting in the rain? You may have noticed rust forming on the brakes, gears or wheels, characterized by a brown/reddish colour. This rusting is caused by the presence of both water and oxygen in contact with the metal. If rusting begins and it is not treated or looked after, the metal will continue to disintegrate, more rusting will appear, and the bike won’t function well.

This is similar to how a cavity forms on your tooth. Instead of oxygen surrounding the bike, bacteria surround the surface of your tooth in the form of plaque (that gooey, sticky, creamy colour substance on your teeth). Plaque contains bacteria (good and bad bacteria), which can be normal and harmless as long as you take care of your teeth by brushing, using toothpaste with fluoride and maintaining a healthy diet. If your teeth are not taken care of, more harmful bacteria can attach onto the surface of your tooth and start to make acid—think of acid like the rainwater on the bike. The bad bacteria use the acid to kill the good bacteria and dominate the plaque. The acid produced can disintegrate the tooth which eventually creates a hole (cavity) on the surface of the tooth!

So… how can green tea, prevent holes in my teeth?

Now that we know that acid made from bad bacteria can cause a cavity on your tooth, how can the tea plant really stop that from happening? Well, studies show that green tea does two main things:

  • Takes away the bacteria’s home and nutrients;

  • Limits bad bacterial growth.

Just like you and me, bacteria need a home to live in and food to eat in order to survive. What happens if you can’t find a home and a stable source of nutrients? You get cold, sick and eventually die; bacteria will die without this too! Normally, the bad bacteria eat sugar and use the sugar to help them stick onto the tooth in the form of plaque (their home); they also use the sugar to create acid. This creates a stable home for the bacteria by providing a protective barrier so that our body can’t enter and kill them. This also provides a safe path for the acid to travel towards the tooth surface and cause damage. Luckily, research shows that green tea destroys some ability of the bad bacteria to consume these sugars; limiting their ability to produce acid and stick onto the tooth. A decrease in acid means that the bad bacteria can’t reproduce and dominate the plaque—so, now it can’t cause much damage to our tooth!

So… does this mean green tea is the cure to cavities?

If only it were that easy... unfortunately, it’s not. Cavities are dependent on many factors including your diet, the type of bacteria that are living in your mouth, the amount of time you let the plaque stay on your tooth (which depends on how well you brush and floss) and the use of fluoride products. If you maintain a good, healthy balance of these factors, there is some scientific evidence that show that green tea reduces the number of bad bacteria in the plaque.

Unfortunately, the scientific evidence on how well green tea actually works in comparison to chlorhexidine (the current best mouthwash to decrease the number of bad bacteria) is unclear. Some studies show that chlorhexidine is better, some show that green tea is better, and some say that they are equally effective—how confusing!

For now, you can keep drinking your green tea in moderation—it’s not harmful as no harmful side effects have been found. But remember to brush and floss regularly, have regular check-ups and contact your dentist for more cavity prevention tips and up-to-date information on the use of green tea!