Young children can get a type of decay called baby bottle tooth decay or early childhood caries. It destroys enamel quickly. This type of decay is common in children who are put to sleep with a bottle of milk or juice. The bottle exposes the teeth constantly to carbohydrates through the night. Bacteria can grow rapidly and produce acid that decays teeth.
Decay can become worse if the parent does not clean the child’s teeth. It can eat through enamel and leave a large cavity in a matter of months.
In older adults, the exposed roots of teeth can develop cavities. This is called root caries. Older adults are more likely to have receding gums caused by years of hard brushing or periodontal disease. They also are more likely to have dry mouth (xerostomia). The decrease in saliva results in less protection of the teeth. This increases the risk of decay. Many common medicines can cause dry mouth. Be sure to ask the doctor or pharmacist if any of your medicines cause dry mouth.
Decay can form beneath fillings or other tooth repairs, such as crowns. Sometimes bacteria and bits of food can slip between the tooth and a poorly placed filling or crown. This also can happen if the filling cracks or pulls away from the tooth, leaving a gap.
The bacteria in your mouth need food to live and multiply. When you eat sugary foods and other carbohydrates, the bacteria use them as food, too. The bacteria then produce acids that can dissolve tooth enamel (outer layer of the tooth).
It’s not just candy and ice cream we’re talking about. All carbohydrate foods eventually break down into simple sugars. These include glucose and fructose. Some of this process begins in the mouth.
Foods that break down into simple sugars in the mouth are called fermentable carbohydrates. These include the obvious sugary foods, such as cookies, cakes, soft drinks and candy. But they also include pretzels, crackers, bananas, potato chips and breakfast cereals.
Bacteria in your mouth turn the sugars in these foods into acids. These acids begin to dissolve the mineral crystals in teeth. The more times you eat each day, the more times your teeth are exposed to an acid attack.
This attack can lead to tooth decay, also known as dental caries. First, the acid begins to dissolve calcium and phosphate crystals inside a tooth. A white spot may appear on the enamel in this weakened area. But the loss of minerals develops beneath the surface of the enamel. The surface may still be smooth.
At this stage, the tooth can be repaired with the help of fluoride, proteins and minerals (calcium and phosphate) in the saliva. The saliva also helps reduce the acid levels from bacteria that attack the tooth.
Once the decay breaks through the enamel to cause a cavity, the damage is permanent. A dentist must clean out the decay and fill the cavity. Left untreated, the decay will get worse. It can destroy a tooth all the way through the enamel, through the inside dentin layer and down to the pulp or nerve of the tooth. That’s why it is important to treat caries at a very early stage, when the process can be reversed.