EFFECT OF GROWTH HORMONE ON GROWTH AND DEVELOPMENT OF THE DENTOFACIAL COMPLEX IN THE YOUNG RAT; A STUDY BY MEANS OF LONGITUDINAL ROENTGENOGRAPHIC CEPHALOMETRICS

For the purpose of studying the hormonal effect on the growth pattern of the dentofacial complex, fifteen young Wistar strain rats were given a daily dose of 0.5mg of growth hormone (NIH-GH-B-12) at 21 to 30 days of age. Roentgenographic cephalograms, which were taken every 10 clays, were analyzed by the coordinates method and linear measurement. In the normal (control) rats, the retrognathic facial pattern changed into the prognathic type at about 20 days of age due to the forward growth of the anterior part of the viscerocranium and the downward growth of the anterior part of the mandible (1967). In the experimental group, the prognathic growth pattern of the dentofacial complex was stimulated by the injections of growth hormone for 10 days. The viscerocranium showed a response to growth hormone, while the neurocranium showed the same growth pattern as that of the control group. The prominence of the nasal and gonial parts and the descent of the anterior part of the mandible were marked.