CHD-FA kills and disrupts multi-species periodontal biofilms. Multi-species periodontal biofilms were grown on Thermanox™ coverslips within 24 well plates for a total of 5 days, with AS media changed every day. Upon biofilm development, cells were treated with 0.5% (v/v) CHD-FA and 0.2% (v/v) CHX for 24 h before being washed with PBS. Reduction in metabolic activity was measured using the alamarBlue® assay (A). All samples were assayed in triplicate, on three separate occasions. Data represents mean ± SD (***p < 0.0001). Biofilms were retained after treatment with CHD-FA or CHX and DNA was extracted for quantification of each species using SYBR® GreenER™ based qPCR (B). Biofilms were also analysed by SEM at either 2000x (C, E, G) and 5000x (D, F, H). These were processed and viewed on a JEOL JSM-6400 scanning electron microscope and images assembled using Photoshop software. Untreated multispecies biofilms were first compared at low magnification (C) to biofilms treated with 0.2% (v/v) CHX (E) and 0.5% (v/v) CHD-FA (G) for 24 h and it was shown that biofilm treatments caused disaggregation. At higher magnification the biofilms treated with 0.5% (v/v) CHD-FA for 24 h resulted in a fibrous ECM, as denoted by arrows (H), as compared to the control (D) and CHX (F).