Antibacterial Activity and Randomised Controlled Trial of Chlorhexidine-Coated Floss on Gingival Bleeding

While Chlorhexidine mouthwash is widely studied for the treatment of periodontal disease, research on chlorhexidine in the form of dental floss is limited. This study aims to evaluate the effect of chlorhexidine wax-coated dental floss on dental plaque accumulation and gingival bleeding. Additionally, antibacterial activity and cellular toxicity were also investigated in vitro.

Various concentrations of chlorhexidine wax-coated floss (0%, 0.12%, 1%, and 2%) were prepared. The antibacterial activity against Streptococcus mutans was studied using a disc diffusion assay. Cellular toxicity was assessed in L929 cells and human gingival fibroblasts using an MTT assay. To evaluate the effects on plaque accumulation and gingival bleeding, 27 participants were randomly divided into 3 groups: 1) 0% chlorhexidine wax-coated dental floss (control), 2) 0.12% chlorhexidine wax-coated dental floss, and 3) 1% chlorhexidine wax-coated dental floss. All participants were instructed to use the provided dental floss once daily at bedtime for 14 days. Six sites per tooth were evaluated for the Quigley-Hein plaque index and bleeding index (BI) at day 0 (baseline) and day 15. All fully erupted teeth, except the third molars, were examined.

Chlorhexidine-coated floss exhibited antibacterial activity against S. mutans in a dose-dependent manner. In an in-vitro study, a 2% concentration of chlorhexidine in the floss was found to be highly toxic, leading to its exclusion from clinical trials. After 14 days of use, significantly lower levels of BI were observed in the groups using chlorhexidine wax-coated dental floss, compared to the control. Additionally, there was no significant difference in BI between the 0.12% and 1% chlorhexidine wax-coated dental floss groups. However, no significant difference in plaque index was found between the groups using chlorhexidine wax-coated dental floss and the control group.

This study demonstrated the antibacterial and anti-gingivitis properties of chlorhexidine wax-coated dental floss. Our results showed that using chlorhexidine wax-coated dental floss at a concentration as low as 0.12% could significantly reduce gingival bleeding. However, no additional benefit of chlorhexidine wax-coated dental floss on dental plaque accumulation was found.