自然头位下拍摄X线头颅侧位定位片的临床意义

Evaluation of true horizontal plane under natural head position as a basis for cephalometric analysis

目的 :探讨自然头位 (NHP)下拍摄X线头颅侧位定位片及用真性水平面 (THP)作参考平面的临床意义。方法 :5 0名广州市 11～ 16岁错牙合畸形患者 ,男 16名 ,女 3 4名 ,每个病例两次摄取自然头位下的X线头颅侧位片 ,间隔时间为 1周。并以铅垂线来确定真性水平面 (THP)。测量SN平面 ,FH平面和THP平面并进行统计学分析。结果 :拍摄X线头颅侧位片时自然头位可重复性好 ,SN THP和FH THP前后对比差异皆无统计学意义 (P >0 .5 ) ;SN THP和FH THP的个体变异程度皆较大。结论 :自然头位下拍摄X线头颅侧位定位片及用真性水平面作参考平面更有临床指导意义。

Objective:To investigate the reliability and validity of True Horizontal Plane (THP) under natural head position(NHP) as a basis in evaluation of sagittal cranofacial relationship.Method: Lateral radiographs were taken under natural head position from 50 malocclusion patients(16 boys and 34 girls), aged 11 to 16 years old with original family home in Guangzhou. The second lateral radiographs were taken in the same way from the same patients after a week. The angles SN-THP and FH-THP were measured from the tracings, with one THP line draw at right angle to the registered plumb line.Result: NHP showed a satisfactory repeatability, and no statistical differences were found between radiographic measurement of SN-THP and FH-THP respectively in different time (P>0.01). Large interindividual variation of both intracranial reference was found. Conclusion:To evaluate the sagittal cranofacial relationship using cephalometric radiographs, natural head position is recommended compared to conventional head position.