Effect of a chlorhexidine varnish on Streptococcus mutans in saliva.

The aim of the present work was to evaluate the effect of a thymol/chlorhexidine varnish at 1% on Streptococcus mutans (S. mutans) in saliva applied after teaching and evaluating an oral hygiene technique and dressing the cavities to reduce the bacterial load. Streptococcus mutans levels in saliva samples and dental status were evaluated in 38 girls between 6 and 13 years of age with high risk of caries. The girls were then trained and assessed in oral hygiene. On day seven, oral hygiene assessment was repeated and supragingival plaque control was performed. After 15 days (day 21) another culture was performed and the level of S. mutans in saliva samples was determined. Evaluation and reinforcement of the oral hygiene technique were repeated and the cavities were dressed to reduce the bacterial load. At 36 days from the onset of the experiment, culture S. mutans counts were performed; evaluation and reinforcement of the oral hygiene technique were undertaken and the girls were divided randomly into two groups: 1 The teeth of the experimental group were painted with a varnish containing 1% chlorhexidine and thymol. 2 The teeth of the control group were painted with a placebo varnish containing only thymol. After a further 15 days (day 51), another culture and S. mutans counts were performed. The results showed a gradual reduction in the S. mutans counts in saliva in each subsequent experimental period analyzed. Significant differences between the experimental group and the control group were recorded after treatment. It can be concluded that the levels of S. mutans decreased in each subsequent experimental period and that the application of a 1% chlorhexidine varnish elicited a significant reduction in S. mutans levels.