Haffajee AD, Bogren A, Hasturk H et al

Materials and Methods: Fifty-eight subjects from Brazil, 26 from Chile, 101 from Sweden and 115 from USA participated in the study. For inclusion, subjects, ranging from 24-82 y.o., presented with at least 14 natural teeth, at least 4 sites with probe depths > 4 mm and at least 4 sites with attachment level of > 3 mm. Demographic information and smoking status was ascertained via questionnaire. Plaque accumulation, gingivitis, BOP, probe depth, attachment level were obtained at 6 sites per tooth. The data for the Chilean population was collected for a prior study utilizing a Florida probe. For the remaining 3 population pools, a North Carolina probe was used. For the Chilean, Swedish and American subjects, subgingival plaque samples were taken obtained from the MB of all teeth. Subgingival plaque from the 4 deepest sites and from 3 sites with probe depth <4 mm were sampled from the Brazilian subjects. Supragingival plaque was removed prior to collecting subgingival plaque with a sterile Gracey curette. The sample was placed in 0.15 ml Tris-EDTA + 0.15 ml of NaOH. All samples were analyzed within 3 months. Samples from Chile, Sweden and The USA were analyzed for 40 bacterial species using checkerboard DNA-DNA hybridization at The Forsyth Institute. The samples in Brazil were analyzed in Brazil by a person trained at Forsyth. The percent of the total DNA probe count was determined for each species.