抄録
This study has been performed to determine how far the atrophic change of the pars alveolaris, caused by the loss of teeth, is influenced by age, sex, number of missing teeth and lapse of time after tooth extraction. The materials used in this study were seventy-four mongrel dogs, which contained fourty-six animals extracted on the lower right posterior teeth. They were divided into eight groups and two subgroups according to age, sex, number of extracted teeth and time after extraction of teeth. Their mandibles were measured bilaterally in square measure of the frontal section at the lower fourth premolar, the lower first and the lower second molar, and the measurement on the right side, or the operated side, and the same on the left side, or the control side, were compared in order to estimate changes in the form of the edentulous mandibular body. The results were as follows: The areal decrease of the frontal section on the edentulous mandibular body takes place in almost all cases, and furthermore the decrease occurs on the dentulous portion being adjacent to the edentulous. The growing show higher degree of the areal decrease than the mature, but these degrees do not vary significantly between the male and the female, and also between the groups extracted on M1 and M3M2M1P4P3P2P1. The square measure of the edentulous mandibular body in the growing decreases markedly during six months after tooth extraction, but subsequently remains constant. On the contrary, in the mature it remains rather fluctuant during twenty-four months after tooth extraction with the exception of the frontal section on the lower first molar.
