AN EXPERIMENTAL STUDY OF CHANGES IN THE WEIGHT OF THE MANDIBLE AFTER LOSS OF LOWER POSTERIOR TEETH

Abstract

The purpose of this study was to observe the influence of loss of the lower teeth on the weight of the mandible. The materials used in this experiment consisted of sixty-seven mongrel dogs, which were extracted on lower right posterior teeth with the exception of control animals, and which were classified according to their age, sex, number of extracted teeth and time after extraction of teeth. Two halves of their mandibles were weighed separated from each other, and the right half, namely the operated side was set against the left, the control side to estimate the changes of the mandible in weight following extraction of the lower teeth. The following results were obtained: The weight of the mandible extracted on lower posterior teeth decreases in growing animals, and appears to be diminished in the mature, although it increases transiently. There is a distinct difference in the change of the weight between the growing dog and the mature, and that is, the former has an intenser change than the later. But there is no significant difference between the male and the female, and also between the animals extracted on all lower posterior teeth and those extracted on the lower first molar. The weight of the mandible in the growing decreases significantly in six months after the loss of the teeth, but subsequently ceases to change. In the mature animal it remains unchanged in three months afte1 the extraction of the teeth, then increases significantly in the period between third month and twelfth, and decreases distinctly afterwards.