Prevention

Sometimes I have a patient and when I tell them they have a cavity they point to their brother or sister sitting in the chair next to them and exclaim “He or She doesn’t ever brush their teeth but I get the cavities, Life is not fair.!”

Well, there are reasons for this. One of them is that plaque that is being brushed off partially consists of little microscopic bugs called bacteria. Some bacteria cause cavities, but many others do not. Interestingly enough there is at least one type of bacteria that may help prevent cavities . It gets tricky because we likely don’t know what all of the bacteria that cause cavities are. This is because there are at least hundreds of different bacteria and other micro-organisms that inhabit the oral cavity. Unfortunately, most of these are difficult to grow outside the mouth on, let’s say, a petri dish. This means that scientist can’t study them and figure out what they eat, what they produce or do.

How do we know there are a lot of bacteria that live in the mouth? It’s from something called PCR or polymerase chain reaction. PCR is basically a laboratory procedure that isolates small amounts of different DNA. It’s from their DNA that we know there are so many.

If you are going to get cavities, you have to have the bacteria in the mouth that cause them. What are some of the bacteria that are known to promote cavities? The main one is called streptococcus mutans , yep, the same family of bacteria that causes strep throat along with a lot of other infections. Another one is Lactobacilli. Let’s focus on S. mutans, an abbreviation for streptococcus mutans.

How does S. mutans cause cavities? This is the simplified explanation. They eat the sugars that you eat. From those sugars they produce acid, the acid dissolves the first layer of the tooth called enamel. Once it has dissolved the tooth through the first layer and gets to the second layer, a hole is created that’s technically called a cavitated lesion or commonly referred to as a cavity. Now, there is a whole lot more very fascinating things going on to create this hole, but this is the jest of it.

By brushing and flossing you are mechanically removing both the bacteria and the food they eat from the tooth surface. The less bacteria and the less food for them to eat equals less cavities overall. Why do people who take really good care of their teeth still get cavities? There are other factors, such as the strength of the enamel, amount of pits and grooves in the teeth and the micro structure of the enamel, along with amount of saliva and other factors. You can’t remove all of the bacteria and for those who still get cavities, there is enough left to cause problems is the short answer. But, you will very likely reduce the number of cavities you would have gotten without good oral hygiene.

Why are there some people who don’t brush and floss but yet don’t seem to get cavities? They may just not have enough S. mutans and other cavity promoting bacteria in their mouth to make a difference. Or maybe they have enough cavity inhibiting bacteria to counteract the S. mutans. Should they continue to ignore oral hygiene? Probably not. As mentioned, there are lot of bacteria in the mouth that don’t cause cavities. Some of these do cause inflammation of the both the gums called gingivitis and bone called Periodontitis. These can lead to periodontal disease, bone loss around your teeth and eventual tooth loosening or loss. One can see the inflamed gum tissue in this photo.

Consider yourself lucky if you don’t have cavities, but still take good care of your teeth. You will likely be glad you did, besides that, who wants dirty teeth or bad breath? Wouldn’t you rather to look like this?