Efficacy of differently concentrated chlorhexidine varnishes in decreasing Mutans streptococci and lactobacilli counts

The objective of the present prospective trial was to compare the efficacy of differently concentrated chlorhexidine varnishes (EC40® = 40% chlorhexidine and Cervitec® = 1% chlorhexidine + 0.1% thymol) on levels of Mutans streptococci (ms), lactobacilli (lb) and plaque formation in interproximal plaque and saliva. Twenty-four volunteers with a high level of ms in saliva were randomized into two groups and treated with the experimental varnishes. Varnish applications were performed in accordance with literature. Over a period of 2 weeks Cervitec® was applied three times and EC40® once or twice, depending on ms counts after first application. Four and 12 weeks after final varnish application ms in plaque and saliva were evaluated. Furthermore, lactobacilli (lb) counts in saliva and the effect on plaque formation were recorded. Both varnishes revealed a reduction of ms in interproximal plaque and saliva after 4 and 12 weeks. The highly concentrated varnish revealed a significantly stronger reduction of ms in plaque and saliva compared with the lowly-concentrated varnish. No effect could be demonstrated on lb counts and plaque formation. The results indicate that the chlorhexidine varnishes tested may reduce ms in both interproximal plaque and saliva. However, the application of the highly concentrated varnish EC40® results in a higher decrease of ms in plaque sites and saliva.