Positive Health Online

Abstract

HAMMER and colleagues, Discipline of Microbiology, School of Biomedical and Chemical Sciences, The University of Western Australia, Crawley, Western Australia, Australia, khammer@cyllene.uwa.edu.au, have investigated the susceptibility of oral bacteria to tea tree oil.

Background

Melaleuca alternifolia (tea tree) oil has been found to have antibacterial properties. Here, these properties were evaluated in oral bacteria in vitro.

Methodology

The activity of tea tree oil against 161 isolates of oral bacteria from 15 genera was determined. Minimum inhibitory concentrations and minimum bactericidal concentrations were measured.

Results

Minimum inhibitory concentrations and minimum bacericidal concentrations ranged from 0.003 to 2.0%. Isolates of Porphyromonas, Prevotella, and Veillonella were the most susceptible to tea tree oil, and isolates of Streptococcus, Fusobacterium, and Lactobacillus were the least susceptible. Time-kill studies with Lactobacillus rhamnosus and Streptococcus mutans with 0.5% tea tree oil showed no signs of viable bacteria after 5 minutes.

Conclusion

These studies show that a range of oral bacteria are susceptible to tea tree oil and suggest that tea tree oil may be useful in oral healthcare products and in the maintenance of oral hygiene.

References

Hammer KA, Dry L, Johnson M, Michalak EM, Carson CF, Riley TV. Susceptibility of oral bacteria to Melaleuca alternifolia (tea tree) oil in vitro. Oral microbiology and immunology 18 (6): 389-392, Dec 2003.