So you brush so diligently, how can you possibly have a Cavity?!!!

We have all heard the stories of how cavities are caused by bacteria generating acid, which dissolve your teeth and cause holes in them. What may be lesser known is that it is a combination of three (3) factors that work to form cavities in our mouth. These factors are the host (that’s you), the bacteria, and the environment (inside your mouth). Like an ongoing battle between Good and Evil these factors must be kept balanced with each other and when the conditions favor one side over the other, that’s when we get problems.

The Good…

It starts with us and what we are born with. Just like how each of us are different from one another, our teeth are also unique. Some of us have teeth that just have thicker enamel than others. Those who are blessed with naturally straight teeth or those of us who have gone through braces will also have an easier time cleaning our teeth than those with more crowded, crooked teeth. Also, our teeth have pits and grooves on them but some of us have those that may be shallower than others, making it harder for food and bacteria to latch on to.

A well under-rated and often less advertised defense mechanism our body has against cavities is our Saliva. Saliva contains enzymes and antibodies that directly attack the bacteria of dental plaque and neutralizes the acid that’s released by these bacteria. Saliva also contains minerals (including Calcium, phosphate) that replace those that were dissolved from the teeth by acid.

The condition of our general health affects the quantity and quality of the salvia that is secreted. Certain health problems (diabetes, Alzheimer’s disease, anemia, cystic fibrosis, etc.) may lower good saliva production and cause “dry mouth.” We can also experience this when we sleep with our mouth open or when we are dehydrated. Many of the medications we take may also cause this. Some of the 400 or so medications that cause the dry mouth side-effect are antihistamines and decongestants (taken for cold and allergy symptoms), and those taken for depression or high blood pressure. One of the unfortunate side effects of radiation therapy for cancers of the head and neck is destruction of salivary gland tissue, which results in dry mouth and subsequent tooth decay.

Taking care of our body and maintaining good overall health will help prevent cavities. But then there are some health issues we may face that we just cannot control and we must take steps to prevent them from indirectly affecting our teeth.

The Bad…

It is estimated that the human mouth holds more than 700 different species of trillions of bacteria. Yes! This number is bigger than the US national debt in a very small space! A number of these bacteria are capable of causing cavities (mainly Mutans streptococci, Lactobacilli, and Actinomyces). These bacteria are able to form a protective layer, called biofilm (or dental plaque), around themselves making it harder to remove them. Then they use the sugar from the food we eat to produce acid that dissolves the calcium phosphate from our tooth enamel. These Bad Bacteria are present in more than 79% of the population and are usually passed on from mother to child. The amount of harmful bacteria varies between one person to another. It can also vary within the same person at different times due to changes in the environment of the mouth. It’s obvious that people with less bacteria in their mouth are less prone to have cavities.

The Environment

The battleground between us and the bacteria is actually the one factor that we have a lot of control over. Bacteria need sugar in order to survive and by limiting how much sugar they are exposed to, we can reduce their capability to form cavities.

It’s not how much you eat but how often you eat! Every time we eat, we expose sugar to the bacteria and the acid they produce lowers the pH in our mouth. Our saliva counters this affect by neutralizing the acid. This process takes, on average, a few hours to bring the pH back to neutral. However, if we decide to have a snack in between meals this will expose more sugar to the bacteria and continue to keep the pH level acidic. The longer the pH level remains acidic, the more minerals are being dissolved from the teeth! This is especially important to beware of if you are on a special diet for a weight loss program or muscle gain.

Brushing and flossing after every meal will help remove the sugar supply before the bacteria can get a chance to use it. Proper technique is important and sometimes it can be difficult to tell if we are doing it correctly because dental plaque can be colorless. There are ‘disclosing’ tablets and mouthwash available at your local pharmacy that stains plaque a different color to help us see if we have missed any areas. No matter how hard you try, there may still be some areas (like the back of your mouth) that you just can’t see and reach or plaque that you can’t remove. This is why routine dental cleanings are needed and recommended.

The type of food and drink that we take in also influence the environment. Some food and drinks (sodas, citrus juices) are more acidic, combining with the acid that is generated by the bacteria to speed up the dissolution of calcium phosphate from our teeth. With this in mind it does help to drink water often and with every meal. Some artificial sweeteners (xylitol, sorbitol) cannot be used by bacteria and so serves a good alternative for sugar in food products.

The introduction of fluoride and fluoridated water has helped reduce the prevalence of caries by 40-50% in communities all over the US since WWII. Brushing with a flouride toothpaste works to promote tooth remineralization. The flouride that is incorporated into the tooth actually makes it even ‘harder’ than when it was initially formed. Flouride can also inhibit the bacteria’s ability to create acid. As with all good things there is a limit to how much fluoride you can have. Too much flouride, especially if swallowed at a young age (under six), may lead to a condition called flourosis where there is a chalk-like discoloration (white spots) of tooth enamel.

If we are more aware of the things we put in our mouth we can control the type of environment we are creating and work to prevent any opportunity for cavities to form.

As you can see and imagine, there are so many different ways to disrupt the balance between these three factors leading to cavities. Regular check-ups with your dentist will help reduce the chances for cavities and detect and treat the ones that are found. Ultimately, Cavity Prevention does not mean just going to the dentist regularly, but an ongoing team effort from both you and your dentist to maintain this delicate balance in your mouth!