Cephalometric characteristics of open bite in adults: a three-dimensional cephalometric evaluation.

The purpose of this study was to evaluate the morphogenetic characteristics that contribute to the development of open bite in adults. The linear dimensions of various maxillofacial structures of adults with anterior open bite were compared to those of a normal adult population. Lateral and posteroanterior cephalometric radiographs were taken of 22 men and 34 women who exhibited an anterior open bite of at least 2 mm. A control group consisted of 27 men and 33 women who had an orthognathic profile, a normal skeletal pattern, and a Class I occlusion. In both men and women with open bite, total facial height (nasio menton) and three dentoalveolar heights--anterior maxillary (maxillary central incisor-palatal plane), posterior maxillary (maxillary first molar-palatal plane), and anterior mandibular (mandibular central incisor-mandibular plane)--were significantly greater than the same dimensions in the control groups. Ramus height (condylion-gonion) and depth, gonial depth, maxillary length (anterior nasal spine-posterior nasal spine), and facial length (basion-point A) were significantly smaller in those with open bite. Mandibular length (gonion-pogion) and facial width were significantly smaller only in the female open bite group. Both male groups had significantly larger measurements than did the female groups. The only exceptions were the nasal width in the control groups and the ramus depth in the open bite groups, for which there were no statistically significant differences between men and women.