Three things need to come together for tooth decay to occur. You need to have a tooth (1), with bacteria (plaque) on it (2), and ingest fermentable carbohydrates (3). The bacteria consume the carbohydrates and produce acid as a byproduct.
How does that work exactly? The bacteria process the sugars and carbohydrates, and produce lactic acid. This localized production of acid begins to dissolve the minerals in the tooth (decay). However, the human body has a defense mechanism against this process, to repair the damage done by acid: saliva. Saliva can remineralize the affected areas if we give it enough time to do so. If saliva does not get enough time, we end up with a loss of healthy tooth.
This graph shows acid level over time when eating or drinking fermentable carbohydrates. Going up means a higher level of acid, going right means more time in minutes. Within 5 minutes of eating sugar or carbohydrates, areas of plaque become acidic to the point where the tooth starts to break down (pH ~5.5). After 15-20 minutes, the acid level begins to return to normal if we haven’t eaten or drank anything else.
Put simply, if we spend too much time above the critical level, our teeth continue to break down. If we are below the critical level, our teeth can remineralize and decay is minimized.
The more we sip and nibble throughout the day, the longer the teeth are exposed to acid. If we sipped our soda or snacked on our crackers every 20 minutes as shown in the graph below, we spend a significantly longer period in the decay zone. This causes continual breakdown of the teeth, and the harder it becomes for saliva to repair the damage. Teeth don’t have time to heal in an acid bath.
So how do we go about preventing decay? The first and simplest thing is to remove the plaque by brushing and flossing. The better we clean our teeth, the less plaque there is to produce acid and cause tooth decay.
The second and perhaps the biggest factor is limiting our exposure to carbohydrates and sugars in both frequency and duration. That is, less sipping and nibbling throughout the day. If we ate whatever we wanted for breakfast, lunch and dinner, with no snacks or sugary drinks in between, tooth decay is less likely to occur because of all the time for saliva to repair the teeth between meals. The decay events are shorter and fewer, giving our bodies ample chance to repair any damage done.
Thirdly, we can incorporate fluoride in to our home care routine. Fluoride can be incorporated into the structure of the teeth. It can makes them stronger (more resistant) to decay. There are a number of ways to add fluoride, from toothpastes to mouth rinses. It is recommended that you brush and floss your teeth, then rinse for 1-2 minutes with a fluoride mouth rinse and go straight to bed. Do not rinse with water, eat or drink for 30 minutes afterward.
The fourth piece of preventing decay is to remediate any existing, active areas of decay. This minimizes damage and helps to prevent the spread of the bacteria throughout the mouth.