MODELING THE RELATIONSHIP BETWEEN CLINICAL, MICROBIOLOGIC, AND IMMUNOLOGICAL PARAMETERS AND ALVEOLAR BONE LEVELS IN AN ELDERLY POPULATION

A CROSS-SECTIONAL PERIODONTAL STUDY Of 74 subjects aged 65 to 75 years was performed. Clinical data were collected and related to microbiolo gical and immunological data. A statistical model (step-wise multiple regression) of factors related to bone loss was created initially usin g clinical data only; then by adding either the microbiologic or immun ologic data; and then by using clinical, microbiologic, and immunologi c data together. When only clinical data were considered, three factor s were found to have significant positive correlations with bone loss. Tooth mobility accounted for 17% of the variability in the alveolar b one level measurements, probing depth for 12%(r(2)), and plaque index for 3%, for a total of 32% of the variability explained by these clini cal factors. Tooth mobility and probing depth were clinical factors wh ich remained significant in the model when the microbiological data we re also considered. As percentages of the total cultivable microbiota, E. corrodens (r(2)=14%) and black-pigmenting Prevotella intermedia (r (2)=4%) correlated positively with alveolar bone loss. The addition of the microbiologic data only increased the r(2) to 33%. When immunolog ical data were considered with the clinical data, pocket depth and too th mobility were the clinical parameters which remained in the model. IgG antibody levels to P. gingivalis W83 and/ or 381 (r(2)=24%) A. act inomycetemcomitans 627 (r(2)=2%) were the significant immunologic meas ures having a positive correlation with bone loss. Anti-F. nucleatum l evels had a significant negative correlation. A total of 50% of the va riability in alveolar bone level was accounted for in the model by the addition of specific serum antibody levels to subgingival plaque micr oorganisms. When clinical, microbiological, and immunological measurem ents were all considered together, antibody to P. gingivalis W83 and/o r 381 (r(2)=42%), percentage of B-lymphocytes (r(2)=3%), probing depth (r(2)=4%), anti-E. corrodens levels (r(2)=2%), and anti-P. gingivalis 33277 levels (r(2)=4%) all had significant positive correlation with loss of alveolar bone. The number of enteric bacteria, anti-F. nucleat um levels, and anti-P. intermedia levels each had a significant negati ve correlation with alveolar bone heights. The r(2) for this model was 75%. These results indicated that antibody levels to subgingival plaq ue microorganisms and tooth mobility were the best predictors of bone loss in the elderly patients tested in this study.