This is a million-dollar question, however, the question I will answer instead is “what contributes to cavities?”

Have you ever noticed that there are people who seem to barely brush their teeth and floss once in a blue moon, and yet they have no cavities? At the same time, there are people who brush twice a day and floss daily, and yet struggle with caries. There is not a single factor that can be pointed to, at least as far as I know, that can be said to “cause” cavities. A cause-and-effect relationship is often very difficult to establish. Nevertheless, these are the most common factors that contribute to cavity formation, in no particular order:

  1. Plaque on teeth (in other words – not brushing and flossing). Plaque is a combination of bacteria and food products (usually the most sticky parts of food products). When plaque is on teeth, it can release acid, which causes the tooth structure to lose minerals, and as the process continues, eventually enough minerals are dissolved where a small hole is formed.
  2. Frequent snacking on carbohydrates. Many carbohydrates, especially grains, have phytic acid, which dissolves teeth. The more frequently a person snacks on these types of carbohydrates, the more frequently the tooth loses minerals, and eventually, when enough minerals are dissolved, a small hole is formed.
  3. Eating and/or drinking sticky processed foods. Have you noticed how teeth feel like they’re coated with something after even one sip of soda? A similar thing happens after eating certain candies. In addition to soda being extremely acidic (which in itself breaks down tooth structure), it also coats teeth with a layer of sticky stuff that attracts more plaque. The more frequently someone sips on soda, the longer the exposure of the mouth to an acidic environment.
  4. The kinds of bacteria in your mouth. There are bacteria that produce a lot of acid when exposed to certain foods, and there are types of bacteria that don’t produce a lot of acid. If someone’s mouth has a lot of the type of bacteria that produces a lot of acid, they have an uphill battle, because even a tiny exposure to sugars causes a huge release of acid into their mouth, which causes their teeth to lose a lot of minerals, while others who do not have those types of bacteria have an easier time going to the dentist. Certain studies have found that bacteria get passed from parents to children, and because bacteria that likes gums often lives on gums while bacteria that likes teeth often lives on teeth, the tooth-type of bacteria gets passed to children when they are about 6 to 18 months of age. Bacteria gets passed from parents or caretakers to children by things like kissing and sharing utensils. However, this is a contributing factor to cavities, and not the sole cause of cavities. Another perspective is that the type of bacteria we have in our mouth grows as a result of the types of foods that our mouth has to process. So, it could be that cavities run in certain families because they eat similar food, and thus have similar types of bacteria … see what I mean? It could go both ways.
These are the 4 most common factors that contribute to cavity formation. So what can you do to reduce your risk of decay? Brush at least twice a day, floss at least once a day, eat carbohydrates only with a meal (don’t snack on carbs), avoid soda by all means, and avoid juices and sticky processed foods. I’m sure as time goes on, there will be more clarity about which factors affect teeth more, but for now, this is what we have. Something you may want to research for yourself is how bleaching teeth affects cavities. It seems like occasional bleaching either reduces that cavity causing bacteria, or it makes people want to take better care of their teeth, but whatever the mechanism, it seems that people with whiter teeth may have less cavities.