Abstract

The present study was undertaken to 1) develop a model to predict the proportion of sites with alveolar bone height reduction over 6 years by means of a few factors, 2) build a second model to predict the initial values of the dependent variable, and 3) describe the relationship between initial bone loss and the bone loss over 6 yr with age. 142 subjects (18-67 yr) were examined radiographically at baseline and 6 yr later using a standardized method. For each subject, the proportion of sites depicting significant alveolar bone height reduction during the study was assessed. Explanatory variables were: presence of initial bone loss, local plaque retaining factors, age, sex, number of missing teeth at baseline and rheumatoid arthritis. Employing multiple regression analysis, the combined effect of initial bone loss, plaque retaining factors, age and rheumatoid arthritis provided the best model suited to predict the proportion of sites undergoing bone loss over time. However, age, plaque retaining factors and number of missing teeth were the best predictors of initial bone loss. A logistic regression model was then used to study the significance of these predictors at the site level. This model indicated that alveolar bone loss over time at a given site is related mainly to presence of local factors and initial bone loss at that site as compared to the effect of other sites with local factors and initial bone loss in the subject. Age demonstrated a linear relationship with initial bone loss and a curvilinear relationship to periodontal disease progression.(ABSTRACT TRUNCATED AT 250 WORDS)