Tooth decay

Some children get a lot of cavities, others almost none. Why is this so? We still don't know all the factors that lead to tooth decay (dental caries), but we do know that heredity plays a role, as do the diet of the pregnant mother, the child and access or lack of access to good dental care.

Bacteria and plaque. The principal cause of tooth decay is acid produced by bacteria living in the mouth. The bacteria combine with food debris to form a material called dental plaque that sticks to tooth surface. The more hours of the day this plaque remains on the teeth, the greater the number of bacteria and the more acid is produced. This acid dissolves the minerals that make up the enamel and dentin of the tooth, eventually destroying the tooth. The bacteria live off sugars and starches in the child's diet. Anything that keeps sugars sitting in the mouth for a long time is likely to be good for the bacteria and bad for the teeth. That is why frequent between-meal snacking promotes tooth decay. Especially harmful are lollipops, sticky sweets, dried fruit, fizzy drinks, which cling to the teeth.
Saliva contains substances that help teeth resist attack by bacteria. Since the body produces less saliva during sleep, nighttime is when cavities form most. That is why brushing the teeth before bed is so important. Foods that promote saliva - such as sugarless gum - can help fight cavities. There are also substances in some sugarless chewing gums, xylitol and sorbitol, that kill cavity-forming bacteria and another substance, casein, that strengthens teeth.

Baby-bottle cavities. An especially severe type of tooth decay is nursing caries or baby-bottle tooth decay. When formula or breast milk sits on a baby's teeth for a long time, the sugars in the milk promote the growth of cavity-forming bacteria, which then destroy the teeth. The teeth most at risk are the upper front teeth, sice the tongue covers the lower teeth during nursing and sucking. There is normally enough time between feedings for the flow of saliva to clean the teeth. But when babies keep a nipple in their mouths much of the time, this normal cleaning may not have a chance to occur. The worst baby-bottle tooth decay happens when babies fall asleep with the bottle in their mouths. While they sleep, formula sits on their teeth and the bacteria multiply away.
Baby-bottle decay may start even before the first birthday. Sometimes nursing caries are so severe that the infected teeth have to be removed. For this reason, a baby should not be put to bed with a bottle of milk, juice or other sweetened fluid. The only acceptable fluid for sleep time is water. Even diluted sweet fluids can promote decay.