Based on current research data the effects of probiotics on periodontal health and its maintenance are not clear. Scientific evidence is poor in this area. Systematic in vitro studies are first needed to learn more about the eventual interactions of probiotic species and periodontal pathogens and oral biofilms, and also about their effects on periodontal host tissue reactions. Thereafter, properly controlled, randomized, long-term clinical trials are needed using the most promising strains and also testing various methods of application.