Our results suggest that regular powder, although effective in removing the dental plaque, was not effective in inhibiting the plaque-forming bacteria. Although the chalk hard plaque was removed, there were still alive and active bacteria present in the treated tooth surface or interdental space as inferred by the in vitro bacterial culture results [Figures S1, S2]. However, the addition of CBD powder appears to enhance the tooth-polishing process by inhibiting the plaque-forming bacteria as inferred by the significant reduction of CFU count on in vitro culture plates [Figures S1, S2]. The results suggest that the addition of CBD to polishing powders might improve the tooth polishing treatments and might help to inhibit and reduce the rebinding ability of plaque-forming bacteria and the formation of new plaque.

The air-polishing technique is a safe and comfortable (for patients) treatment for tooth polishing without adverse effects on the enamel.[911] However, the technique has a drawback of creating extensive aerosols that contain bacteria, blood, and saliva together with plaque and polishing powder particles from the patient.[816] A recent study on microbial composition and spatial distribution of dental aerosols has reported the bacterial contamination of human origin and water origin and emphasized the importance of infection control measures in dental clinics, including the dental water line.[17] Aerosols in dental clinic pose a potential threat to the dentist and dental assistants of various infections, including respiratory track infection such as pneumonic plague, TB, SARS, MERS, and COVID-19.[16181920] Especially, with the present pandemic situation of COVID-19, dentists and dental assistants are at tremendous risk as the virus spread through droplets in air by oral, nasal, and eye mucus membranes.[1820] Several viral and bacterial infections can spread from patients to dentists and their team and eventually to other patients through cross-contamination from aerosols.[19] It is essential, therefore, to upgrade the tooth polishing procedure to minimize aerosol-mediated infections, and it is feasible to achieve this by simple modification of polishing powders. Based on our previous reports[1415] and this study results, CBD-supplemented powder has the potential to reduce the risk of aerosol-mediated infection by inhibiting the bacteria. Although the current study is limited to in vitro analysis, the results are significant and suggest a strong potential of cannabinoids in reducing the dental aerosol-mediated infections. However, this needs to be tested by an analysis of the aerosol samples collected from the close proximity of patients receiving CBD-supplemented polishing.

Air polishing was initially used for supragingival plaque removal; however, by substituting the powder with a low-abrasive powder such as glycine powder, the same technique is also applied for subgingival plaque removal without causing damage to the soft tissues.[89] Similarly, in addition to CBD supplementation in the powder phase, a new liquid formulation with CBD infusion to replace water for the liquid phase in the air polisher can also be developed in future to further increase the inhibition of plaque-forming bacteria. The dental water line may have bacterial contamination[17]; such liquid formulation with CBD might reduce the risk of such contaminants, further improve the subgingival and supragingival plaque removal, enhance the overall tooth polishing by inhibiting the bacteria, and finally, further reduce the risk of infections from the dental aerosols. The current study demonstrates a simple improvisation of the existing air-polishing technique and is easy to implement without any need for modification of the existing protocol. With the help of its anti-quorum sensing properties,[21] and as demonstrated in this study, cannabinoids have the potential to enhance the overall performance of tooth polishing treatment.