The objectives of the study are: 1) to determine whether alveolar bone loss is influenced by changes in mineral metabolism, 2) to compare changes in alveolar bone with those occurring in other parts of the skeleton, 3) to investigate the underlying metabolic changes accompanying alveolar bone loss. The study will use two strains of mice, one known to be susceptible to severe alveolar bone loss (STR/N) and one resistant to alveolar bone loss (random bred Swiss-Webster strain). Dietary Ca:P ratios will be varied in the range 1:1 to 1:4 at two levels of calcium in the diet, 0.1% (Ca deficient) and 0.6% (adequate Ca). In a separate study, the zinc level of the diet will be varied from adequate (20-25 ppm) to marginally deficient (5-10 ppm). Alveolar bone loss will be quantitated by direct measurement, and histometrically in the interradicular area of the low second molar. Metabolic changes will be assessed by measurement of mineral content, lysosomal enzyme levels, and by acid production in bone culture. Changes in alveolar bone will be compared with changes in the femur on the basis of rapidity of onset, severity of bone loss, and extent of change in metabolic patterns.