As children we are constantly bombarded with the message that if you brush your teeth you won't get cavities. Unfortunately, this is simply not the case. The process of tooth decay is a complex, bacterial driven process that brushing alone will not solve.
A cavity is formed when a specific bacteria, Streptococcus mutans, ingests carbohydrates. Strep. mutans is a very common microbe and is found in most peoples' mouths. The bacteria will ferment the carbohydrate and as a byproduct produce acids that attack tooth structure. The breakdown of tooth surface will provide the bacteria more area of the tooth to colonize and the process accelerates.
Dentistry, as a profession, has over simplified this process. We educate our patients that brushing and flossing will prevent decay. This is not true. Brushing and flossing will reduce the number of bacteria in the mouth but you cannot sterilize your mouth by brushing. Brushing and flossing is the key to healthy gums but is only a small part of preventing cavities.
For tooth decay to form three ingredients must be present; a tooth, the proper bacteria, and food for the bacteria. We have already examined that brushing will not sterilize the mouth so bacteria will be present. If you are reading this we will assume you have teeth. The third ingredient in cavity formation is the one we have the most control over, our diet.
Now everyone assumes that the advice is going to be to never eat anything fun again. While that would be effective it is unrealistic. Besides, we have already discussed that it's not just "Bad Foods" that contribute to decay. We stated earlier that all carbohydrates can promote decay, this is fact. Yes, some foods are better at feeding the bacteria, such as; very sticky foods like caramel, cereal or chips that get stuck in the chewing surface of your tooth, and acidic foods with carbohydrates, like soda, all give the process a boost. But the key is all fermentable starches can lead to cavities. The good news is you have a defense for this process.
Your saliva is the mouth's natural defense and it works to stop the breakdown of tooth structure and repair damage that has occurred. Let's refresh our chemistry lessons. All compounds have a specific Ph. water is neutral at Ph 7. A Ph below 7 is acidic and above 7 is basic or alkaline. Acids and bases when combined work to neutralize each other. So why is this important when discussing tooth decay? First, saliva is usually slightly basic so it acts to neutralize the acids that the bacteria have formed. Second, saliva functions as a reservoir of minerals. These minerals will act to rebuild the damage that any acids formed have caused. This is an amazing system at work but it takes time to happen. It will typically take four hours for neutralization and rebuilding to occur.
From this information you can start to understand that it is the frequency of carbohydrate intake that really determines how at risk someone is for decay. Let me explain. If you were to have toast with jelly at 8am the bacteria would also enjoy the toast and jelly because both have carbohydrates that can be utilized and acid would be formed. The saliva would also begin its job of neutralization and rebuilding. Let's say at 9am you had a cup of coffee, your second at this point, with cream and sugar. With the sugar in your coffee the breakdown continues because the neutralization and rebuilding is not complete from the toast. 11am comes and you grab a snack, a power bar because the protein will take that hunger away. With the protein in your power bar comes more carbohydrates to keep our bacteria friends eating. Then lunch, your afternoon snack, dinner, dessert after dinner and you can see how easy it is to never get out of acid production and back to sound teeth.
Now, with this model how, is it that anyone has teeth? The answer is that not everyone is the same. I'm sure you know people who can eat anything, all the time, and have great check-ups. That happens because their bacterial mix does not contain enough of our nemesis S. mutans to create enough acid to cause problems. For others their dietary habits, either through eating infrequently or by eating a low carbohydrate diet, do not promote tooth decay.
So if you do get cavities are you just destined to get more? Fortunately, the answer is no. There are several steps you can take in changing your risk of getting future cavities.