By Nancy Volkers
InteliHealth News Service

A study in China has found that decay in a baby tooth (or primary tooth) is a risk factor for defects in the enamel of the permanent tooth that replaces it.

The study took place in an area of southern China that does not have a fluoridated water supply. Researchers examined 288 children between ages 3 and 7 to look for decay in their primary teeth. About eighty-five percent had some decay, 80 percent of which had not been treated.

As the children reached age 11 or 12, the researchers examined them again to look for defects in the enamel of their permanent teeth. In the 66 children examined so far, 16 percent had some defects in their permanent teeth. Defects were found in 29 percent of permanent teeth replacing primary teeth that had decay at age 3. Defects were found in only 13 percent of permanent teeth replacing primary teeth that never had decay.

The earlier the age at which decay occurred in primary teeth, the greater the chance of enamel defects in the corresponding permanent teeth.

The study is being conducted at the University of Hong Kong. These preliminary results were presented March 9 at the International Association of Dental Research meeting in San Diego.