Dynamic killing effectiveness of mouthrinses and a d-enantiomeric peptide on oral multispecies biofilms grown on dental restorative material surfaces

Abstract

Objective: To evaluate the dynamics of killing of oral multispecies biofilms grown on dental restorative materials by commercially available mouthrinses and a d-enantiomeric peptide.

Methods: Four composite resins (3 M Supreme, 3 M Supreme flow, Kerr Sonicfill, and Shofu Beautifil II) and one glass ionomer (GC Fuji II) were used as restorative materials. Plaque biofilms were grown on the surfaces of restorative material discs for 1 week. The surface roughness and biofilm attachment were assessed by atomic force microscopy and scanning electron microscopy. One-week-old biofilms grown anaerobically at 37 °C were exposed to each of five solutions for one minute (twice daily for seven days): Listerine Total care and Paroex Gum mouthrinses, 0.12% chlorhexidine, 0.001% d-enantiomeric peptide DJK-5, and sterile water. The dynamic variation of the biovolume of the biofilms and the percentage of dead bacteria were monitored and analyzed using confocal laser scanning microscopy.

Results: All restorative materials had similar surface roughness with intact biofilm attachment. The percentage of dead bacteria and biovolume of biofilms treated by each oral rinse solution remained constant between days 1 and 7, with no statistically significant difference. DJK-5 showed the highest percentage of dead bacteria (up to 75.7%; cf. ∼20-40% for other mouthrinses) of all solutions tested within 7 days.

Conclusions: DJK-5 outperformed conventional mouthrinses in killing bacteria in oral multispecies biofilms grown on dental restorative materials.

Clinical significance: The antimicrobial peptide DJK-5 is effective against oral biofilms and serves as a promising candidate for the development of future mouthrinses to improve long-term oral hygiene.

Keywords: Biofilm; Composite; Mouthrinse; Peptide; Surface roughness.