Tooth-building material for dental care.

Healthy teeth are strong bulwarks of crystalline calcium phosphate. Cavities and painful sensitivity to hot and cold foods result when these tooth minerals are lost. Scientists have now found a way to replace this same tough material. Their discovery could lead to toothpastes, mouth rinses, and even chewing gums that remineralize teeth.

Dental researchers have long sought a way to make calcium phosphate dissolve and then recrystallize on teeth. And they needed this process to happen fast - in just five minutes - in order for the material to do its trick during tooth-brushing.

At the National Institute of Standards and Technology in Gaithersburg, Md., researchers led by Ming S. Tung have developed a form of calcium phosphate that fits the bill. It's amorphous - that is, there's no consistent order to the material - so it dissolves quickly and easily, It also precipitates on teeth in the hard crystalline form.

The American Dental Association has patented the fluffy, white material. Enamelon, Inc., a company in Yonkers, N.Y, has begun to make gum and toothpaste with it and to test these products in clinical trials. Other companies have shown interest in developing a mouthwash. Tung says his groups preliminary results suggest that rinsing with amorphous calcium phosphate does effectively treat temperature-sensitive teeth. "The beauty of this is that it's preventive," he adds.