A simplified laboratory procedure to select an appropriate antibiotic for treatment of refractory periodontitis.

THE FEASIBILITY OF USING A simplified laboratory procedure to select an appropriate antibiotic for treatment of refractory periodontitis was investigated. Six different antibiotics were added to commercially available CDC-agar plates. Plaque samples from periodontal pockets were inoculated onto the plates. The percentage kill was determined by comparing colony counts on the antibiotic-containing medium with those on the control plates. The three most effective antibiotics were ranked by visual inspection as well as by colony count. It was determined that visual inspection may be used to determine an effective antibiotic.