MORPHOLOGIC ADAPTATION OF TEMPOROMANDIBULAR-JOINT AFTER CHINCUP THERAPY

The purpose of this study was to clarify the morphologic changes of th e temporomandibular joint (TMJ) after chincup application, with longit udinal TMJ cephalometric laminagraphs. The subjects were 19 prepuberta l patients with true, mild skeletal Class III malocclusions with anter ior crossbite. All underwent chincup therapy from the beginning of tre atment. The control subjects were 16 patients with functional anterior crossbite, with normal jaw relationships. Cephalometric laminagraphs and lateral cephalograms were obtained before and after treatment. Sta tistical analysis of the data revealed the results as follows: (1) The chincup therapy changed the direction of growth of the mandible, espe cially, the ramus swing-back. (2) The chincup group showed a relativel y more slender mandibular neck compared with the control group. (3) Th e condylar heads were bent forward after the chincup application, and the glenoid fossa was deepened and widened. The clearance between cond yles and fossae was decreased by the orthopedic force of the chincup a ppliance.