Oregano Oil is Highly Antimicrobial Against Oral Pathogens
Objectives: Dental caries and periodontal disease are two of the most common infectious diseases in humans and treatment of these diseases can result in a high financial burden for patients. In addition to traditional methods of oral hygiene, many people have begun using organic essential oil products to combat caries risk and periodontal disease. Our goal was to determine how effective various essential oil treatments are at eliminating viable organisms using a range of oral pathogens.
Methods: We assessed the efficacy of killing both caries-associated and periodontal disease-associated bacteria by several commonly used essential oils in duplicate assays on at least three different days. Using a two-minute antimicrobial exposure followed by bacterial plating assay we tested the ability of essential oils from tea tree, eucalyptus, peppermint, sage, and oregano to kill Streptococcus mutans, Actinomyces naeslundii, and Veillonella parvula (caries-associated bacteria) and Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans (Aa) (gram-negative periodontal pathogens). The antimicrobial effects of these essential oils were compared to those of Listerine Naturals™, a commercially available mouth rinse.
Results: While most essential oils tested had modest antimicrobial activity against oral pathogens (0-90% killing), oregano oil stood out as having the most potent activity against the broadest range of pathogens with >99.99% killing of all pathogens tested. Furthermore, oregano oil had antimicrobial activity equal to Listerine Naturals™. Aa stood out as particularly sensitive to almost all essential oils tested.
Conclusions: Oregano oil is highly antimicrobial against multiple organisms known to be associated with both caries and periodontal disease, with equivalent antimicrobial activity to Listerine Naturals™. Aa appears to be especially sensitive to the antimicrobial effects of Oregano oil. Future studies will assess the ability of essential oils, especially oregano oil, to kill oral pathogens present in a biofilm resembling dental plaque.