Biofilms are the main challenges in the treatment of common oral diseases such as caries, gingival and endodontic infection and periimplantitis. Oral plaque is the origin of microbes colonizing in the form of biofilms on hydroxyapatite (tooth) and titanium (dental implant) surfaces. In this study, hydroxyapatite (HA) and titanium (Ti) disks were introduced, and their surface morphology was both qualitatively and quantitatively analyzed by a scanning electron microscope (SEM) and atomic force microscope (AFM). The average roughness of Ti disks (77.6 +/- 18.3 nm) was less than that of HA (146.1 +/- 38.5 nm) (p < 0.05). Oral multispecies biofilms which were cultured on Ti and HA disks for 6 h and three weeks were visualized by SEM. We investigated the ability of two new antibiofilm peptides, DJK-5 and 1018, to induce killing of bacteria in oral multispecies biofilms on Ti and HA disks. A 6-h treatment by DJK-5 and 1018 (2 or 10 mu g/mL) significantly reduced biomass of the multispecies biofilms on both Ti and HA disks. DJK-5 was able to kill more bacteria (40.4-75.9%) than 1018 (30.4-67.0%) on both surfaces (p < 0.05). DJK-5 also led to a more effective killing of microbes after a 3-min treatment of 3-day-old and 3-week-old biofilms on Ti and HA surfaces, compared to peptide 1018 and chlor-hexidine < 0.05). No significant difference was found in the amount of biofilm killing between Ti and HA surfaces. Both peptide DJK-5 and 1018 may potentially be used as effective antibiofilm agents in clinical dentistry.