In the article the relation between initial mobility of incisors of both jaws and the level of marginal alveolar bone is described. The regression lines representing the dependence of mobility on marginal bone level at various loading forces confirm stepwise the nature of the force transmission from tooth to periodontal support tissues. The dependence of regression line slope on increasing inflammatory periodontal pathology indicates increasing loading of alveolar bone over tension of connective tissue fibers as well as increasing of pressure. This can further accelerate alveolar bone resorption.