There are a number of risk factors that contribute to the development of cavities in the mouth, but the two main ones are a diet that is high in starch and sugar, and the presence of plaque-forming bacteria in the mouth. When these bacteria combine with the food you eat and your saliva, they form plaque, a sticky substance that eventually becomes tartar if allowed to stay on the teeth. Plaque also turns sugar into an acid that causes cavities by dissolving teeth.
Plaque tends to settle in the areas at the top of the gum line, in between teeth, and in the fissures and pits found at the top of teeth. Cavities initially start to form in the enamel or outer layer of the tooth before eventually penetrating the dentin or inner layer. It is only when the cavity reaches this point before you can start to notice any problems.
Thus, one of the major risk factors for tooth decay is the genetic structure of your teeth. For example, if you have small teeth that have numerous grooves and pits, you are more prone to cavities than if you had larger teeth. Having crooked teeth that are poorly aligned is also a big risk factor in developing cavities since there are more places where plaque can collect.
Other risk factors include:
Snacking. If you frequently snack in-between meals or sip on sweet sodas, you are at greater risk of developing cavities. The sugars in your diet provide the bacteria in plaque with the fuel that it needs to produce more tooth-dissolving acid.
The particular foods that you should avoid eating too much of, since they tend to stick to your teeth for a long time, include ice cream, cookies, cakes, dry cereal, hard candy and snack chips.
Inadequate tooth care routine. If you do not brush your teeth after eating sweet and sticky foods, there is a greater chance that the food residue will eventually become plaque, and start the process of decaying your teeth.
Your age. The people who are most prone to cavities are those who are either very young (children and teens), or older (senior adults). The reason for this is that children have a tendency to consume more sweet foods, while older adults are prone to receding gums, which can make them susceptible to root decay.
Worn dental devices or fillings. Old fillings can break down, resulting in rough edges where plaque can develop. In addition, when dental devices no longer properly fit, it can cause plaque to start developing in the areas underneath them.
Inadequate fluoride. This naturally occurring mineral is essential in reversing the early stages of tooth decay, and preventing cavities. You can get fluoride from the water that you drink, as well as from toothpaste and mouthwash.