Dental caries, its surface susceptibility and dental fluorosis in South India.

Objective: To correlate water fluoride levels with dental caries and dental fluorosis in areas with different levels of fluoride in the drinking water and to establish the surface susceptibility of dental caries in an endemic fluoride area.

Methods: 544 schoolchildren 12 to 15 years of age from the Davangere region of India were examined. The DMFS index was used to measure dental caries, which was further differentiated into smooth surface and pit and fissure lesions. Dean's index was used to diagnose dental fluorosis. Five villages with fluoride levels ranging from 0.43 ppm to 3.41 ppm were studied.

Results: There was a highly significant negative correlation (r = -0.16) between water fluoride levels and dental caries. Dental fluorosis increased from 16% at 0.43 ppm to 100% at 3.41 ppm. Pit and fissure lesions made up the vast majority of the lesions in all the villages and showed a decreasing trend with increasing fluoride levels, however no such trend was seen for smooth surface lesions.

Conclusions: Water fluoride was an important factor responsible for the low caries prevalence. The prevalence of fluorosis and low caries even in low fluoride areas may point to a halo effect.