Observations of biofilm growth on human dentin and potential destruction after exposure to antibiotics

ObjectivesThis study was performed to observe biofilm formation on dentin and to then observe effects of clinically achievable antimicrobial drug concentrations on these biofilms.Study designWild-strain endodontic bacteria were anaerobically cultured from necrotic pulps of extracted human teeth and used to grow biofilms on sterilized dentin slices in an anaerobic chamber for 12 days. Then these biofilms were exposed to ampicillin, doxycycline, clindamycin, azithromycin, or metronidazole. Each day for 8 days, specimens were fixed using 2% glutaraldehyde and examined with a scanning electron microscope (SEM).ResultsThe SEM images revealed the presence of a mature biofilm after 8 days of growth and that none of the antibiotics tested was effective in eliminating the biofilm even after 8 days of exposure.ConclusionBiofilms are formed in a few days and are resistant to antimicrobial drugs.