THE EVANSTON DENTAL CARIES STUDY

XI. THE CARIES EXPERIENCE RATES OF 12-, 13-, AND 14-YEAR-OLD CHILDREN AFTER EXPOSURE TO FLUORIDATED WATER FOR FIFTY-NINE TO SEVENTY MONTHS

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

In considering the changes in decayed, missing, and filled rates, the DMF rates per hundred children, per hundred teeth, and per hundred surfaces all give about the same percentage reduction.

The maxillary anterior teeth decayed and filled rates were reduced about 23 per cent for the 12- and 13-year-old children, while the reduction for the 14-year-old students of 9.06 per cent was not considered significant. The mandibular anterior teeth decayed and filled rate reductions were not significant. The increase in immune permanent dentitions was statistically significant only for the 13-year-old groups, and here an increase of 139.21 per cent was noted. However, the increase was only 1.42 cases per hundred children when 1952 was compared to 1946.

The percentage reduction change in the dental caries rates for the 12-, 13-, and 14-year-old children after exposure to fluoridated water from fifty-nine to seventy months was approximately 18.51 per cent for the combined ages. This reduction is considered to be statistically significant. The reduction to date appears to be approximately 4 per cent for each year of fluoridation.