How Do Cavities Form? Part III: Time
We’ve described two of the necessary factors for the formation of tooth decay, specifically sugar and bacteria. The third factor, time, will be today’s subject. All three are necessary for cavities to form. The better we understand about the formation of cavities, the better we can make recommendations for prevention and treatment.
Cavity-causing bacteria feed on the things we eat. They grow best under sugary conditions. A cavity forms when specific bacteria consume sugar. The byproduct of their metabolism is acid. This acid is secreted onto the surface of a tooth and does microscopic damage. Over time, if these bacteria are left undisturbed, the prolonged exposure to acid causes a hole, or “cavity”, in the tooth.
Tooth decay does not happen overnight; it is not an acute condition. It occurs when these bacteria remain undisturbed, in the same place, for long periods of time. The best way to disturb the cavity-causing bacteria is to remove them mechanically, with a toothbrush! This is why we recommend brushing twice per day, for two minutes, with fluoride toothpaste. Eliminating bacteria from the surface of a tooth gives the tooth a chance to recover from the acid exposure. Minerals in our saliva, namely calcium and phosphate, help to remineralize or “heal” the acid damage. Fluoride also plays a major role in healing damage from acid.
Bacteria, if left undisturbed for long periods of time, can cause tooth decay. But also the more often that those bacteria are fed, the faster they multiply! This is why we always discuss minimizing the “time of exposure” to sugary foods and drinks. One habit in particular – fruit juice frequently throughout the day – gives those bacteria exactly what they want, and allows them to multiply at a much faster rate. Minimizing exposure to sugar and carbohydrates to three meals and two snacks per day is a great way to prevent tooth decay!
Now that we’ve made it through all three factors, you can see what is necessary for cavities to form. Lots of sugar for a long time, but no cavity-causing bacteria present, and no cavities will form! No brushing, plenty of cavity-causing bacteria, but no sugar? No cavities! In reality, those situations can’t happen. But if we continually try to improve in all three areas, we can be assured that we’re doing everything possible to prevent cavities for our kids!