Antimicrobial activity of nanoparticulate metal oxides against peri-implantitis pathogens

Dental plaque accumulation may result in peri-implantitis, an inflammatory process causing loss of supporting bone that may lead to dental implant failure. The antimicrobial activities of six metal and metal oxide nanoparticles and two of their composites against bacterial pathogens associated with peri-implantitis were examined under anaerobic conditions. The activities of nanoparticles of silver (Ag), cuprous oxide (Cu2O), cupric oxide (CuO), zinc oxide (ZnO), titanium dioxide (TiO2), tungsten oxide (WO3 ), Ag + CuO composite and Ag + ZnO composite were assessed by minimum inhibitory (bacte- riostatic) concentration (MIC) and minimum bactericidal concentration (MBC) determination against Prevotella intermedia, Porphyromonas gingivalis, Fusobacterium nucleatum and Aggregatibacter actino- mycetemcomitans. Time–kill assays were carried out to examine the dynamics of the antimicrobial activity with ZnO nanoparticles. MIC and MBC values were in the range of <100ﰀg/mL to 2500ﰀg/mL and <100 ﰀg/mL to >2500 ﰀg/mL, respectively. The activity of the nanoparticles tested in descending order was Ag > Ag + CuO > Cu2O > CuO > Ag + ZnO > ZnO > TiO2 > WO3. Time–kill assays with ZnO demonstrated a significant decrease in growth of all species tested within 4 h, reaching 100% within 2 h for P. gingivalis and within 3 h for F. nucleatum and P. intermedia. Coating titanium surfaces of dental and orthopaedic implants with antimicrobial nanoparticles should lead to an increased rate of implant success.