Ichida T, Itoh Y, Nodai E, Fujita K, Sato M
Nihon Kyosei Shika Gakkai Zasshi. 1989 Aug;48(4):443-53.
The present study was undertaken to determine the effect of mandibular displacement occurring in lateral roentgenocephalometry at the open mouth position and of the resulting changes in the projected sites on linea measurements of the mandible. With use of a brachicephalic young (corresponding to age 7) and a dolichocephalic adult human dried mandible, lateral roentgenocephalograms taken under different conditions with angles and distances varied, simulating clinical lateral roentgenocephalometry at the open mouth position, were compared and studied. The results were as follows: 1. Displacement from 5 mm to 30 mm perpendicular to the central X-ray caused unfixed changes, presumed to be human errors in measuring, in the following ranges; brachicephaly: 0-1.4%, dolichocephaly: 0-0.9%. 2. As angles of rotation perpendicular to the central X-ray increase from 0 to 10 degrees clockwise, significant reduction in inverse proportion to the increase in angles of rotation were found; Cd-Gna: brachicephaly: 1.3%, dolichocephaly: 0.9-1.4%; Go-Gna: brachicephaly: 1.6-3.3%, dolicocephaly: 1.4-2.2%. However, unfixed changes in the following ranges were found for Cd-Go; brachicephaly: 0.5-2.3%, dolicocephaly: 0.6-1.2%. 3. Increase in angles of rotation counterclockwise also showed a similar tendency to that in clockwise rotation.
本研究旨在确定在开口位进行侧位头颅X线测量时下颌移位的影响，以及由此导致的下颌骨测量线上投影部位的变化。使用一个短头型青年（相当于7岁）和一个长头型成人干燥下颌骨，比较并研究在不同条件下（角度和距离变化）模拟开口位临床侧位头颅X线测量所拍摄的侧位头颅X线片。结果如下：1. 垂直于中心X线的5毫米至30毫米移位在以下范围内导致了不确定的变化，推测为测量中的人为误差；短头型：0-1.4%，长头型：0-0.9%。2. 垂直于中心X线的顺时针旋转角度从0度增加到10度时，发现与旋转角度增加成反比的显著减小；髁突-颏下点（Cd-Gna）：短头型：1.3%，长头型：0.9-1.4%；下颌角-颏下点（Go-Gna）：短头型：1.6-3.3%，长头型：1.4-2.2%。然而，髁突-下颌角（Cd-Go）在以下范围内发现了不确定的变化；短头型：0.5-2.3%，长头型：0.6-1.2%。3. 逆时针旋转角度增加也显示出与顺时针旋转类似的趋势。
