Adjunctive chitosan hydrogel suppresses biofilm after treatment with a chitosan brush in a peri-implantitis model in vitro

Objectives To evaluate the antimicrobial effects of debridement using an oscillating chitosan brush (OCB) alone or in combination with a novel chitosan hydrogel (LGX) on biofilm-contaminated dental implants. Methods Fifty commercially available dental implants were inoculated with a multispecies biofilm consisting of Porphyromonas gingivalis , Fusobacterium nucleatum , Streptococcus intermedius and Actinomyces naeslundii and were subsequently allocated to four treatment-groups: (A) mechanical OCB-debridement alone, (B) OCB with adjunctive LGX, (C) OCB and LGX followed by removal of hydrogel excess with saline and (D) untreated biofilm controls. Post treatments, implants were re-incubated in new brain heart infusion (BHI) anaerobically and were rolled out on Brucella-blood-agar-plates at four timepoints. After three days the proportions of colonized surfaces were evaluated. Total bacterial DNA was quantified using quantitative PCR. Confocal laser scanning microscopy was used to examine post-treatment effects on established and newly formed biofilm. Results All treatments significantly reduced bacterial DNA-abundance and colonized surface area compared to untreated controls. Re-growth at later timepoints was significantly attenuated and sustained after treatments with adjunctive LGX-use compared to OCB alone, which did not differ from untreated controls. LGX led to less newly formed biofilm evaluated with confocal microscopy compared to OCB alone. Conclusions Within the limitations of this study, it is reported that LGX reduced bacterial growth up to seven days when used as adjunct to mechanical debridement of contaminated implant surfaces. LGX appears to be a promising therapeutic candidate for the non-surgical treatment of peri-implantitis. However, robust clinical investigations are warranted to validate its efficacy and safety.