[Dissertations 25 years after date 21. Enhancing resistance to bacteria with chlorhexidine varnish and probiotics].

The aim of the research described in 'Chemotherapy against Streptococcus mutans' was to increase colonization resistance against mutans streptococci by inoculating Actinomyces naeslundii on the dentition. Actinomyces naeslundii established better after chlorhexidine application than after dental cleansing only but did not exceed the 1% level of the total actinomyces population. This was insufficient to increase the colonization resistance against mutans streptococci. A 33% chlorhexidine varnish was developed. After a single short-term application of the varnish all plaque bacteria were erased. After several hours Streptococcus sanguinis, Streptococcus oralis, Streptococcus mitis and Streptococcus gordonii re-established on the surface. Actinomyces naeslundii recovered later, but often with higher numbers. Mutans streptococci remained suppressed for months. This led to less acid production in dental plaque and caries reduction. The combination of mechanical cleansing and varnish application resulted in additional pocket reduction. Recently, attention is also established for research on the application ofprobiotics in periodotology.