RESUMO
The quantitation of salivary Streptococcus mutans (S. mutans) according to Köhler and Bratthall and the evaluation of oral hygiene index (OHI-S) by Greene and Vermillion were examined before and after oral preventive measures in 359 schoolchildren at 7-13 years old, sampled from primary schools in three Amphoes of Phetchabun. At the first examination, it was found that 93.9% of the total schoolchildren had S. mutans and most of them had less than 50 CFU. In addition, 11.4% of the samples had this microorganism more than 100 CFU (Comparable to 10(6) CFU/ml. of saliva) and regarded as a high caries risk group. The average values of OHI-S in different age groups of schoolchildren varied from 1.75 to 2.25 and only 15.9% was classified to be in the group of good oral hygiene (OHI-S,0-1.2). However no significant relationship was recorded between the number of S. mutans and the oral hygiene status (p greater than 0.05). The second examination indicated the improvement of oral hygiene status after preventive measures (p less than 0.05) but the number of S. mutans was not significantly changed (p greater than 0.05).
