A major study to relocate, re-examine and collect risk factor information on children who were classified as having localized juvenile periodontitis, generalized juvenile periodontitis or incidental loss of periodontal attachment in the 1986-87 National Survey of the Oral Health of U.S. Schoolchildren was undertaken. Research objectives are to: (1) assess the progression of periodontal destruction among the cases of early onset periodontitis, (2) characterize the microbial ecology of the sub-gingival plaque among persons with early onset periodontitis, and (3) compare the presence and concentration of selected putative pathogens and high-resistance factors among individuals with early onset periodontitis to controls. A sample of subjects were selected whose oral examinations from the 1986-87 National Survey of the Oral Health of U.S. Schoolchildren indicated early onset periodontitis or other severe periodontal problems. From the same national survey two controls per case matched by age, gender, race and geographic location were also located and invited to participate in the study. During FY'93, examinations were made on approximately 265 young people 19-25 years of age. Full mouth oral examinations for periodontal measures and dental caries were conducted. Biological specimens, blood, gingival crevicular fluid and subgingival plaque fluid were also collected. A questionnaire including such variables as medical history, family history, and dental utilization was administered at the time of the oral exam. Dental examination data was edited and summary measures derived. Laboratory analyses of serum, plaque and gingival crevicular fluid were conducted by a number of different laboratories. Relationships among the many clinical and laboratory variables measured are being evaluated.