Effectiveness of Preprocedural Mouthwashes: A Triple-Blind Randomised Controlled Clinical Trial

Abstract Objective: to determine and compare the effectiveness of three Government-recommended pre-procedural mouthwashes in the mitigation of respiratory pathogens during dental care. Material and Methods: 228 participants were block-randomised to the pre-procedural mouthwash groups: Povidone-iodine, Hydrogen Peroxide, and Chlorhexidine Digluconate. Participants rinsed with mouthwashes prior to dental treatment. Participants, operators, and assessors were blind to the assigned mouthwashes (triple blind). A multitude of respiratory pathogens (19 viruses including SARS-CoV-2) were assessed. Changes in the prevalence and mean number of ‘any’ pathogen were determined. Results: All completed the trial and there were no significant differences in the demographic profile with respect to intervention groups (all, P>0.05). The prevalence of ‘any’ detected respiratory viral pathogens in the pre-procedural saliva was 3.5% (8/228) compared to 1.3% (3/228) in post-procedural saliva, P=0.034. The mean number of viruses reduced significantly following pre-procedural mouthwash use: 0.04 (SD 0.18) to 0.01 (SD 0.11), P=0.025. There was no significant difference in the reduction (∆) of ‘any’ detected virus (prevalence), P=0.155, nor any significant reduction in mean number (∆) of ‘any’ detected virus in the post-procedural saliva compared to the pre-procedural saliva of participants with respect to mouthwash used, P=0.375. Conclusions: The HKSAR recommended practice of pre-procedural mouthwash use was effective in the mitigation of respiratory pathogens during dental aerosol-generating treatment. Clinical Relevance: The present study lends support for the HKSAR’s policy on pre-proceduralmouthwashes in the mitigation of respiratory pathogens during dental care, this has implications for practice and policy during pandemics.