Biomedical subjects
Publications and source records attributed to W Hickory.
Histologic and radiographic studies of controlled force application to the maxillae of monkeys show varying rotational effects on the maxilla, dependent on the direction of force application.
This discussion emphasizes that nutrition is an important factor, influencing the general health and tissue tolerance of orthodontic patients on many levels. While orthodontists will rarely see frank manifestations of nutritional deficiencies, it should be recognized that suboptimal levels of certain nutrients are common and have an effect on the biologic responses of the tissues influenced by orthodontic treatment. Additionally, the age group typically involved in orthodontic treatment has particularly high nutritional demands and particularly poor dietary behavior.
This study investigated the effects of moderate zinc deficiency on the development of rat fetal skeleton. Eighteen pregnant rats were fed zinc deficient diet (1.3 ppm) from days 3 to 15 of gestation. An additional 18 rats were pair fed the same diet supplemented with 100 ppm zinc and served as controls. The levels of zinc in plasma were determined on days 15 and 20 of gestation and in the amniotic fluid on day 20. The pregnant rats were killed on day 20 and fetuses were cleared and stained with alizarin red. The weight of zinc deficient fetuses was significantly less than that of controls. The uncleared, as well as stained zinc supplemented fetuses, showed no anomalies. The alizarin stained experimental fetuses showed severe anomalies of long bones, vertebrae, and ribs. The overall calcification of bones was also considerably less as compared to zinc supplemented controls. The zinc levels were significantly less in plasma (day 15) and amniotic fluid (day 20) of experimental dams. The results also indicated that although moderate zinc deficiency does not cause external craniofacial malformations, it severely affects the calcification and development of cranial bones.