What Is It?
Dental caries is the scientific term for tooth decay or cavities. It is caused by specific types of bacteria. They produce acid that destroys the tooth's enamel and the layer under it, the dentin.
Many different types of bacteria normally live in the human mouth. They build up on the teeth in a sticky film called plaque. This plaque also contains saliva, bits of food and other natural substances. It forms most easily in certain places. These include:
- Cracks, pits or grooves in the back teeth
- Between teeth
- Around dental fillings or bridgework
- Near the gum line
The bacteria turn sugar and carbohydrates (starches) in the foods we eat into acids. The acids dissolve minerals in the hard enamel that covers the tooth's crown (the part you can see). The enamel erodes or develops pits. They are too small to see at first. But they get larger over time.
Acid also can seep through pores in the enamel. This is how decay begins in the softer dentin layer, the main body of the tooth. As the dentin and enamel break down, a cavity is created.
If the decay is not removed, bacteria will continue to grow and produce acid that eventually will get into the tooth's inner layer. This contains the soft pulp and sensitive nerve fibers.
Tooth roots exposed by receding gums also can develop decay. The root's outer layer, cementum, is not as thick as enamel. Acids from plaque bacteria can dissolve it rapidly.
Symptoms
Early caries may not have any symptoms. Later, when the decay has eaten through the enamel, the teeth may be sensitive to sweet, hot or cold foods or drinks.
Diagnosis
A dentist will look for caries at each office visit. The dentist will look at the teeth and may probe them with a tool called an explorer to look for pits or areas of damage. The problem with these methods is that they often do not catch cavities when they are just forming. Occasionally, if too much force is used, an explorer can puncture the enamel. This could allow the cavity-causing bacteria to spread to healthy teeth.
Your dentist will take X-rays of your teeth on a set schedule, and also if a problem is suspected. They can show newly forming decay, particularly between teeth. They also show the more advanced decay, including whether decay has reached the pulp and whether the tooth requires a root canal.
Newer devices also can help to detect tooth decay. They are useful in some situations, and they do not spread decay. The one most commonly used in dental offices is a liquid dye or stain. Your dentist brushes the nontoxic dye over your teeth, then rinses it off with water. It rinses away cleanly from healthy areas but sticks to the decayed areas.
Some dentists also use high-tech devices such as lasers to detect cavities. Under many conditions, these devices can detect very early tooth decay, which can actually be reversed.
Expected Duration
Caries caught in the very early stages can be reversed. White spots may indicate early caries that has not yet eroded through the enamel. Early caries may be reversed if acid damage is stopped and the tooth is given a chance to repair itself naturally.
Caries that has destroyed enamel cannot be reversed. Most caries will continue to get worse and go deeper. With time, the tooth may decay down to the root. How long this takes will vary from person to person. Caries can erode to a painful level within months or years.
Prevention
One way you can prevent cavities is by reducing the amount of plaque and bacteria in your mouth. The best way to do this is by brushing and flossing daily. You also can use antibacterial mouth rinses to reduce the levels of bacteria that cause cavities. Other rinses neutralize the acid in your mouth to make the environment less friendly to the growth of these bacteria.