Objective:　The　objectives　of　this　study　were　to:　(1)　develop　a　bioactive　endodontic　sealer　via　dimethylaminohexadecyl　methacrylate　(DMAHDM),　2-methacryloyloxyethyl　phosphorylcholine　(MPC)　and　nanoparticles　of　amorphous　calcium　phosphate　(NACP)　for　the　first　time;　and　(2)　evaluate　inhibition　of　early-stage　and　mature　multispecies　endodontic　biofilm,　bond　strength　to　root　canal　dentine,　and　calcium　(Ca)　and　phosphate　(P)　ion　release.　Methods:　A　series　of　bioactive　endodontic　sealers　were　formulated　with　DMAHDM,　MPC,　and　NACP.　Root　dentine　bond　strength　was　measured　via　a　push-out　test.　Three　endodontic　strains,　Enterococcus　faecalis,　Actinomyces　naeslundii,　and　Fusobacterium　nucleatum,　were　grown　on　endodontic　sealer　disks　to　form　multispecies　biofilms.　Biofilms　were　grown　for　3　days　(early)　and　14　days　(mature).　Colony-forming　units　(CFU),　live/dead　assay,　metabolic　activity　and　polysaccharide　were　determined.　Ca　and　P　ion　release　from　endodontic　sealer　was　measured.　Results:　Incorporating　DMAHDM,　MPC　and　NACP　did　not　decrease　the　push-out　bond　strength　(p　＞　0.1).　Adding　DMAHDM　and　MPC　reduced　endodontic　biofilm　CFU　by　3　log.　DMAHDM　or　MPC　each　greatly　decreased　the　biofilm　CFU　(p　＜　0.05).　Endodontic　sealer　with　DMAHDM　+　MPC　had　much　greater　killing　efficacy　than　DMAHDM　or　MPC　alone　(p　＜　0.05).　Endodontic　sealer　with　DMAHDM　+　MPC　had　slightly　lower,　but　not　significantly　lower,　Ca　and　P　ion　release　compared　to　that　without　DMAHDM　+　MPC　(p　＞　0.1).　Conclusions:　A　novel　bioactive　endodontic　sealer　was　developed　with　potent　inhibition　of　multispecies　endodontic　biofilms,　reducing　biofilm　CFU　by　3　log,　while　containing　NACP　for　remineralization　and　possessing　good　bond　strength　to　root　canal　dentine　walls.　Clinical　significance:　The　new　bioactive　endodontic　sealer　is　promising　for　endodontic　applications　to　eradicate　endodontic　biofilms　and　strengthen　root　structures.　The　combination　of　DMAHDM,　MPC　and　NACP　may　be　applicable　to　other　preventive　and　restoration　resins.　(C)　2017　Elsevier　Ltd.　All　rights　reserved.