Prevalence of dental caries and Streptococcus mutans in Meo of Northern Thailand.

The prevalence of dental caries was studied in 505 Meo, a minority of Northern Thailand, using the DMFT index. Plaque material from all patients was examined qualitatively for S. mutans. The DMFT (dmft) index score ranged between 1.69 and 7.06 with a mean of 2.17 +/- 3.24 for men and 3.45 +/- 3.72 for women. There was a statistical difference in caries prevalence between males and females (P less than 0.05). There was no statistical correlation between miang chewing and caries prevalence. Fluoride concentration of water samples was between 0.043 and 0.077 ppm F-. Of 505 plaque samples, 13.3% were positive for S. mutans, mostly of biotype I. Compared to other Northern Thai hill tribes and the Thai rural population, the Meo appear to have a higher dental caries prevalence rate.