Caries Experience Among 12-year-olds in Different Fluoride Concentration Areas, Russia

Objectives: To assess caries level among 12-year-olds in areas with different fluoride content in drinking water.
Methods: As a part of 3^rd National Oral Health Survey, 5455 12-year-olds from 103 areas of Russia were randomly selected and examined by calibrated dentists using WHO criteria in 2016. Fluoride (F) concentration in drinking water was measured in all areas. Mean DMFT were compared between areas with different levels of fluoride by using t-test. Correlation between DMFT and fluoride concentration was evaluated by Pearson’s coefficient. The study was approved by the Ethical Committee of Moscow State University of Medicine and Dentistry.
Results: The mean DMFT in examined 12-year-olds was 2.26±0.10. Fluoride-content in drinking water was low (0.21±0.02 mg/l, varied from 0.02 to 0.65 mg/l) in 92 areas, optimal (0.93±0.07 mg/l, 0.76-1.16mg/l) in 5 areas; and high (3.96±1.15 mg/l, 1.67-8.95mg/l) in 6 areas.
The mean DMFT in low F-concentration areas (n=4979) was 2.36±0.10, however varied from 0.51±0.11 to 5.92±0.51 mg/l (p<0.001). In optimal (n=258) and high (n=216) F-concentration areas mean DMFT were 1.29±0.50 (0.50±0.13-3.24±0.17, p<0.001) and 1.50±0.28 (0.32±0.15-2.70±0.57, p<0.01), respectively. The mean DMFT in examined 12-year-olds was higher in areas with low F-content compared to areas with optimal (p<0.05) and high (p<0.01) F-content in drinking water. Difference in mean DMFT in areas with optimal and high F-content was not significant (p>0.05). Moderate negative correlation between DMFT level in 12-year-olds and fluoride concentration in drinking water was observed (r=-0.30, p<0.05).
Conclusions: There was a lower DMFT among 12-year-olds in areas with high fluoride content in drinking water in Russia. However, significant difference in DMFT in low F-content areas may indicate, that other possible factors, such as dental plaque, sugar, local use of fluoride, as well as prevention programs could play a major role in caries development.