THE EVANSTON DENTAL CARIES STUDY

VI. A COMPARISON OF THE PREFLUORIDE WITH THE POSTFLUORIDE CARIES EXPERIENCE OF 6-, 7-, AND 8-YEAR-OLD CHILDREN IN THE STUDY AREA (EVANSTON, ILL.)

¹ Walter G. Zoller Memorial Dental Clinic, University of Chicago, Chicago, Ill.

The examinations in the postfluoride period show an increase in the caries rate for the deciduous teeth of the 6- and 8-year-old groups.

The children examined during 1948 showed an over-all lowering in the decayed, missing, and filled rate for all permanent teeth, as well as a reduction in the caries experience of the occlusal surface of the first permanent molars. Accordingly, there was a rise in the number of permanent molars free from occlusal surface caries or fillings, except for the 6-year-old age group. The maxillary and mandibular anterior teeth showed a lowered caries rate for all three ages. There were less precarious lesions-deep pit and fissures in the 1948 examinations.

Statistical analysis of the data indicates a marked reduction of caries prevalence in the permanent teeth of the 6-, 7-, and 8-year-old school children. Comparison of the caries rate in deciduous teeth for the same children, on the otherhand, does not indicate any trend. From the above data the effect of sodium fluoride may be assumed to be greater on the permanent teeth of these children than on their deciduous teeth. The average permanent tooth of these children has been exposed to sodium fluoride for almost its entire posteruptive life. The average deciduous tooth, on the other hand, was present in the child's mouth a considerable time before it was exposed to sodium fluoride.

We feel that while the data indicate some trend that they are far from conclusive. It cannot be assumed at this early time, and cannot be attributed to chance, that the changes that have taken place are necessarily due to the addition of sodium fluoride.