There may not be sound human tooth in the world by 3000 A.D., according to Reidar F. Sognnaes, Charles A. Brackett Professor of Oral Pathology.

In a recent issue of Scientific American, Sognnaes reported that human teeth are steadily deteriorating, and that if this trend is not checked, sound teeth in another 1050 years will be memory of the past.

Through research at the University, he and James H. Shaw, assistant professor of Dental Medicine, have discovered that dental enamel is actually composed in part of living organic matter, not of purely inorganic matter, as was formerly supposed. This research has enabled them to learn considerable information about the causes of tooth decay.

"These discoveries," Sognnaes states make clearer what is involved in the decay of a tooth. The micro-organisms that are believed to cause decay. . . are much wider than the individual crystal and organic units that make up the enamel. Hence, before a micro-organism can invade the enamel, both the organic and the inorganic matter (or the bond between the two) must be destroyed or weakened in some way."

Sognnaes and Shaw have shown that enamel is also quite dependent on the rest of the body. Using radioactive cancer elements in their University laboratory, they have discovered an unceasingly way traffic of ions in the enamel zone of calcium and phosphorous, a freely exchangeable.