Hormonal effects on orthodontic tooth movement in cats—A pilot study

Abstract

s of papers presented before the Research Section of the American Association of Orthodontists, Ne’w Orleans, La., May 3, 1971 Changes in Tongue Position and Activity Following Mandibular Osteotomy N. A. Wickwire and W. R. Proffit University of Kentucky, College of Dentistry, Lexington, Ky. This study of tongue response and activity was developed from serial cephalometric films and lingual pressure recordings. Preoperative and postoperative cephalograme were analyzed to determine the extent and direction of changes of the odontoid process, the body of the hyoid, and the mandible following surgical treatment. The postoperative response of the mandibular setback in nineteen of twenty-two patients was a posterior deflection of the hyoid body. The hyoid was elevated or depressed in negative correlation with mandibular vertical positioning. In the absence of mandibular vertical change, the vertical changes of the hyoid related to the direction and extent of the hinging of the odontoid process, These movements of the hyoid served to preclude change in the pharyngeal space. This constancy enforces the concept of reflex maintenance of airway patency. Analyses made 1 year postoperatively showed stable mandibular positioning in ten patients. Five patients showed mandibular anterior repositioning, with a mean of -0.6 mm. In three of these patients with mandibular relapse the hyoid was seen to be assuming a more anterior position. Lingual pressure changes, as measured by pressure transducers mounted in a palate-covering device, also indicate that the tongue repositions after the surgical procedure, then returns somewhat toward its original position in the postoperative period. Tongue-tip pressure in most patients decreases after surgery, then returns to approximately the original level. If tongue-tip pressure increases after the operation, the incisor position is likely to be unstable, and a