Effect of caries preventive measures in children highly infected with the bacterium Streptococcus mutans.

The number of Strep. mutans in saliva samples was examined in 101 13-14-year-old children, 53 in a control and 48 in the test group. All in the test group with 2.5 X 10(5) Strep. mutans per ml saliva were treated with 1 per cent chlorhexidine gel, once a day, for 14 days when the number of Strep. mutans was greatly reduced. Saliva samples were then examined in the test group every 4th month and all children with Strep. mutans levels above 2.5 X 10(5) were treated. A few selected children had fissure sealants applied to the occlusal surfaces. After 3 years, the mean number of new carious lesions was 9.6 in the control group and 4.2 in the test group. In the children with 10(6) Strep. mutans at the start of the study, the corresponding figures were 20.8 compared with 3.9. Thus a reduction in caries activity can be achieved by controlled antimicrobial treatment.