The cariogenic potential of milk

Abstract

Reports differ concerning the cariogenic potential of milk. Some authors indicate that plain milk can cause dental caries, while others believe that the disease results from adding carbohydrates to the milk. Still others suggest that milk has a protective effect and may contribute to caries prevention. The present study investigated the capability of human milk, plain bovine milk, a milk formula, and milk with honey to produce caries-like lesions in an environment which simulated the oral cavity. Four groups of eight sound bicuspids each, which had been extracted for orthodontic reasons, were mounted in a mouth simulator. The teeth and complete apparatus were sterilized with ethylene oxide. The teeth were then inoculated with human saliva and covered with linen cloth to facilitate bacterial colonization. Each day the various groups of study teeth were exposed to one of the four milk solutions during a 2, 4, or 8-hour period. After each period, a sterile chemical solution simulating human saliva was dropped (8-12 ml/hr) over the cloth to provide a mouth-like environment. A control group was not exposed to a milk preparation. The results indicate that after six weeks, all milk solution groups showed unequivocal signs of decalcification, with an intensity proportional to the period of exposure to the study solutions. Plain bovine milk produced the least decalcification, followed in order by milk formula, human milk, and milk and honey. It can be inferred, from these results, that milk itself, without addition of extra carbohydrates, has the potential to produce dental caries if left stagnant over the tooth surfaces for a sufficient time.