05 July 2023

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Bactericidal capacity of an innovative mouthwash based on a D-enantiomeric peptide

Lara Figini

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Oral biofilms, composed of multi-species microbial communities, play a fundamental role in triggering dental diseases such as caries, pulpal and periodontal inflammation.

Apart from the tooth surface, the surface of dental restorations should also be considered an important platform for biofilm adhesion and bacterial growth. The surface roughness of restorations can influence early bacterial adhesion on composite resins, increasing the risk of oral infections, resulting in significant damage to natural teeth and supporting tissues, and increasing the need for frequent replacement of the restoration.

Therefore, in the case of patients at elevated risk of caries it is essential to effectively eliminate oral bacteria residing in biofilms on restorative materials to ensure the maintenance of a healthy oral microbiome and mitigate dysbiosis.

The "chemical control" of plaque is a valid and acceptable principle if combined with adequate "mechanical" oral hygiene obtained by brushing. Rinses with chlorhexidine have been shown to be safe and effective but should be used in the short to medium term.

Antibiofilm (antimicrobial) peptides have been suggested for the treatment of multi-species oral infections and appear to be effective against biofilms formed by both Gram-negative and Gram-positive bacteria. Specifically, the DJK-5 peptide (a D-enantiomeric cationic peptide) has recently attracted much attention for its broad-spectrum antibiofilm capability in the biomedical sector.

Materials and methods

In an in vitro study, published online in the Journal of Dentistry in May 2023, the authors evaluated the dynamic bactericidal capacity of some commercially available conventional mouthwashes in comparison with that of an innovative mouthwash based on a D-enantiomeric peptide against biofilms oral multi-species grown on different dental restorative materials.

Four composite resins (3M Supreme, 3M Supreme flow, Kerr Sonicfill and Shofu Beautifil II) and a glass ionomer cement (GC Fuji II) were used as restorative materials. Plaque biofilms were grown on the disc surfaces of various restorative materials for 1 week.

Surface roughness and biofilm attachment were evaluated by scanning electron microscopy. One-week-old biofilms grown anaerobically at 37°C were then exposed to each of the five solutions for one minute (twice a day for seven days). The mouthwashes used were Listerine Total Care, Paroex Gum with 0.12% chlorhexidine, 0.001% D-enantiomeric peptide DJK-5 mouthwash and sterile water.

The dynamics were monitored and the change in biovolume of biofilms and the percentage of dead bacteria was analyzed by laser scanning confocal microscopy.

Results

All restorative materials investigated in this study had similar surface roughness with intact biofilm attachment. The percentage of dead bacteria and the biovolume of biofilms treated by each oral rinse solution remained constant between days 1 and 7, with no statistically significant differences.

DJK-5 showed the highest percentage of bactericidal activity (up to 75.7%; vs ~20-40% for other mouthwashes) among all solutions evaluated within 7 days.

Conclusions

From the data of this study, it can be concluded that DJK-5 surpasses conventional mouthwashes in terms of bactericidal activity against oral multi-species biofilms grown on dental restorative materials.

For more information: "Dynamic killing effectiveness of mouthrinses and a D-enantiomeric peptide on oral multispecies biofilms grown on dental restorative material surfaces."