THE EVANSTON DENTAL CARIES STUDY

VII. THE EFFECT OF ARTIFICIALLY FLUORIDATED WATER ON DENTAL CARIES EXPERIENCE OF 12-, 13-, AND 14-YEAR-OLD SCHOOL CHILDREN

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

The exposure time of the 12-, 13-, and 14-year-old children to sodium fluoride has been for 23 to 34 months. The rates show a reduction of 12.19 per cent for these children in the decayed, missing and filled permanent teeth.

The precarious lesions of the permanent teeth were reduced by 55.7 per cent for the 12-year-olds, 38.80 per cent for the 13-year-olds and 33.3 per cent for the 14-year-olds. The 13-year-old children demonstrated the greatest increase in immune cases, that of 146.0 per cent. An increase of that amount appears rather staggering but when considering the actual number of immune cases per 100 children, 1.02 in 1946, the increase to 2.51 in 1949 is only 1.49 cases per 100 children.

The lowered caries rate for Evanston in 1949 is apparently attributed to the fluoridated water. There is a reduction in the dental caries experience of the permanent teeth of all three age groups. This reduction may be due partially to the very widespread use of the urea dentifrices. Topical application of sodium fluoride is now given to many patients. We have made a determined effort to have accurate records of its use in Evanston. There may be a slight inclination toward better oral hygiene by the students as they become acquainted with the study by our frequent visits in the schools. However, until a definite percentage reduction of the caries rate of the study area is established that is materially less than the prevailing caries rate of the control area, where we know that topical application of sodium fluoride is given and urea dentifrices probably are used to about the same extent as in Evanston, we feel that this reduction shown here may not be assumed to be due entirely to the action of sodium fluoride.