@Nullo – eating apples stimulates the production of saliva which reduces the potential for tooth decay. if you don’t like apples, you could eat celery or carrots.
This is from Readers Digest website.
Fresh fruits, especially apples, are better choices. Fresh fruit, although both sweet and acidic, is much less likely to cause a problem, because chewing stimulates the saliva flow. Saliva decreases mouth acidity and washes away food particles. Apples, for example, have been called nature’s toothbrush because they stimulate the gums, increase saliva flow and reduce the build-up of cavity-causing bacteria. A chronically dry mouth also contributes to decay. Saliva flow slows during sleep; going to bed without brushing the teeth is especially harmful. Certain drugs, including those used for high blood pressure, also cut down saliva flow.