Abstract

Background 
Dental plaque is a global health problem affecting people of various age groups. Cannabinoids are gaining enormous research attention due to its beneficial properties for various applications. A preliminary observation on antimicrobial property of cannabinoids against dental plaque bacteria has been reported recently. As a follow-up research, here we report the in vitro evaluation of cannabinoids infused mouthwash products against total culturable (aerobic) bacterial content from dental plaque samples.

Methods
We tested two cannabinoid-infused mouthwash products containing cannabidiol (CBD) and cannabigerol (CBG) respectively (each mouthwash containing < 1% cannabinoid by weight) in vitro against total-culturable bacteria from dental plaque samples collected from 72 adults aged between 18 and 83 years. The participants were grouped on the basis of Dutch periodontal screening index (DPSI) score. To compare the efficacy of our products, we included two most commonly available products over the counter (Product A and Product B) to represent commercially available mouthwash products and the gold standard chlorhexidine digluconate 0.2% as a positive control. The product A represents mouthwash containing essential oils and alcohol, and Product B represents alcohol-free mouthwash that contains fluoride. All the mouthwash products were evaluated directly as such without any dilution through disc diffusion and agar well diffusion approaches and the diameter of zone of inhibition was measured. The limitation in methodology was that, the samples were open-label and the person who performed the manual measurements was unblind to test and control products used.

Results
On average, the cannabinoids infused mouthwash products showed the similar bactericidal efficacy as that of chlorhexidine 0.2%. Both chlorhexidine 0.2% and cannabinoids infused mouthwash products were effective against all the samples tested. Product A did not show any significant antimicrobial activity in any of the samples tested, except that a very marginal inhibition with a zone of 7-8 mm was observed only in 9 samples. Product B did not show any detectable inhibition zone at all in any of the samples tested. The ranges of zones of inhibition (and their average) were 8–25 mm (18.1 mm) for CBD-mouthwash, 8–25 mm (17.7 mm) for CBG-mouthwash; 12–25 mm (16.8 mm) for chlorhexidine 0.2%; 0–8 mm (0.1 mm) for Product A; and 0 mm for Product B. Although the difference in performance was slightly higher than chlorhexidine in both the cases, the difference was statistically significant for CBD-mouthwash and near significant for CBG-mouthwash. No significant difference was observed between CBD- and CBG-mouthwash. No significant difference in performance was found between DPSI score groups for any of the product tested. To our knowledge this is the first report on such efficient mouthwash product with natural key ingredients including cannabinoids and without any kind of fluoride or alcohol.

Conclusions
Our in vitro results demonstrate the potential of cannabinoids in developing efficient and safer mouthwash products and next generation oral care products without fluoride and alcohol.