SUBGINGIVAL MICROBIOTA IN ADULT CHINESE - PREVALENCE AND RELATION TO PERIODONTAL-DISEASE PROGRESSION

THE ''CHECKERBOARD'' DNA-DNA HYBRIDIZATION technology was used to stud y the epidemiology of 18 microbial species associated with various sta tes of periodontal health and disease, in a sample of 148 Chinese subj ects never exposed to systematic dental therapeutic intervention, aged 30 to 39 and 50 to 59 years, Our aims were to: 1) describe the preval ence of these microorganisms; 2) correlate the microbiological and cli nical profiles of the subjects; and 3) examine the association between the microbiological variables and the longitudinal changes of periodo ntal status that occurred over a preceding 10-year period. A maximum o f 14 subgingival samples were obtained from each subject-1,864 in all. The frequency of occurrence of the 18 species examined was high in th is Chinese population, on both the subject and the tooth site level. H owever, all species were not found equally capable of reaching high nu mbers in the subgingival samples and, as a rule, colonized heavily onl y limited proportions of tooth sites within each mouth. There was a pr ofound increase of certain species such as Porphyromonas gingivalis, T reponema denticola, and Bacteroides forsythus in deep pockets or progr essing sites. Multivariate techniques using the subgingival profile co uld effectively discriminate between deep/shallow pockets and progress ing/ stable tooth sites. The microbiological variables showed an enhan ced discriminating potential when classifications were performed on th e individual subject level. Colonization by P. gingivalis, B. forsythu s, Campylobacter rectus, and T. denticola at levels exceeding certain thresholds entailed a significantly increased probability (odds ratios >4) for an individual subject to harbor deep pockets or progressing t ooth sites.