A number of important problems arise in the daily practice of dentistry that are related to the calcification of the teeth. These include the effects of pregnancy on the teeth of the mother, prenatal and postnatal calcification, the influence of the endocrine organs, the effects of dietary factors, mottled enamel, caries and the question of withdrawal of calcium from teeth.
NORMAL CALCIUM METABOLISM
An intelligent answer to any of these questions requires an understanding of the normal processes. Yet it appears that the normal processes cannot be understood until the valuable clues that come from pathologic and experimental studies have been obtained. Claude Bernard,1 the father of experimental medicine, pointed out that disease is nature's experiment to cope with an abnormal condition. If there is recovery, nature's experiment is successful. Significant information has come and will come from careful observation of nature's methods of combating diseases which are experimentally