Incorporation of zinc into cetylpyridinium chloride mouthwash affects the composition of multispecies biofilms.

This study evaluated the effect of a mouthwash containing 0.075% cetylpyridinium chloride and 0.28% zinc lactate (CPC + Zn) in a multispecies biofilm model. A 7-days 33-species biofilm, formed on Calgary device, was 1-min treated with: 0.12% chlorhexidine (CHX), culture medium (negative control), 0.075% cetylpyridinium chloride (CPC) or CPC + Zn, 2x/day, from day 3 until day 6. The metabolic activity and the microbial composition were evaluated by colorimetric method and checkerboard DNA-DNA hybridization, respectively. The three antimicrobials (CPC, CPC + Zn and CHX) reduced metabolic activity, total biofilm count and several species counts, including Porphyromonas gingivalis, Fusobacterium nucleatum, Parvimonas micra, Campylobacter gracilis and Streptococcus mutans. However, only CPC + Zn reduced counts of the pathogen Prevotella intermedia and did not interfere with the levels of some beneficial species in relation to the negative control. The treatment of multispecies subgingival biofilm with CPC + Zn was effective in controlling periodontal pathogens and favored the colonization of health-associated bacterial species.