Positive Health Online

Abstract

SONG and COLLEAGUES,   1 Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, 210029, China;           2 Department of Pediatric Dentistry, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, 210029, China; 3 Department of Stomatology Nanjing First Hospital Nanjing Medical University, Nanjing, China;   4 Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, 210029, China. yfmei@njmu.edu.cn ;          5 Department of Pediatric Dentistry, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, 210029, China. yfmei@njmu.edu.cn  evaluated  the Antibacterial Properties of Tea Tree Oil on Planktonic and Biofilm-Forming Streptococcus mutans. 

Background

Streptococcus mutans (S. mutans) is the principal etiologic agent in the occurrence of human dental caries and the formation of biofilms on the surface of teeth. Tea tree oil (TTO) has been demonstrated to exhibit a wide range of pharmacological actions that can effectively inhibit the activity of bacteria.

Methodology

In this context, we evaluated the in vitro antimicrobial effects of TTO on S. mutans both during planktonic growth and in biofilms compared with 0.2% CHX (chlorhexidine). We determined the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) using the microdilution method, the bacteriostatic rate using an MTT assay, and the antimicrobial time using a time-kill assay. Then, we explored the effects of TTO on acid production and cell integrity. Furthermore, the effects of TTO on the biomass and bacterial activity of S. mutans biofilms were studied. Finally, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to investigate the structure and activity of biofilms.

Results

The MIC and MBC values were 0.125% and 0.25%, and the bacterial inhibition rate was concentration dependent. TTO can effectively inhibit bacterial acid production and destroy the integrity of the cell membrane. Electron micrographs revealed a reduction in bacterial aggregation, inhibited biofilm formation, and reduced biofilm thickness. The effect of TTO was the same as that of 0.2% CHX at a specific concentration.

Conclusion

In summary, we suggest that TTO is a potential anticariogenic agent that can be used against S. mutans.

References

Yu-Meng Song  1 , Hong-Yan Zhou  1   2 , Ye Wu  3 , Jue Wang  1   2 , Qian Liu  1   2 , Yu-Feng Mei  4   5. In Vitro Evaluation of the Antibacterial Properties of Tea Tree Oil on Planktonic and Biofilm-Forming Streptococcus mutans  AAPS PharmSciTech.  21(6):227. doi: 10.1208/s12249-020-01753-6. Aug 6 2020.