摘要
目的 :探讨头影测量标志点在治疗前后位置的改变对角度测量值变化的实际影响。方法 :选用 48例青少年安氏 I类及 类错牙合患者治疗前后的头颅侧位片 ,以正畸临床常用的 4个具有代表性意义的角度测量项目 SNA、ANB、NAPg和 UI/ SN为因变量 ,以构成这些角度的头影测量标志点为自变量进行逐步回归分析 ,从入选回归方程的标志点及其决定系数大小判断各标志点位移对相应角度测量值的影响。结果 :上述 4个角度所作回归方程的决定系数分别为 0 .96 ,0 .95 ,0 .39和 0 .99。结论 :除了 NAPg,其它 3个角度的变化基本能反映出颌骨及牙齿在矢状方向的位置改变 ,但 SNA角的变化在一定程度上同时受 N点水平向位移的影响 ,使其反映 A点水平向位置改变的可靠性受到影响。
objective:To identify changes of clinically used angular measures before and after orthodontic treatment and to study the variance induced by the displacement of each of the landmarks used in the angle's construction.Method:Using stepwise regression,changes in representative cephalometric angles were compared with the linear displacements of the anatomical landmarks from which they were constructed.Coordinate data were obtained from pretreatment and post treatment lateral cephalograms for 48 adolescent patents in a random sample from the practice of a single experienced orthodontist.Incremental R 2 values for the horizontal (x) and vertical(y)contributions of each landmark to the changes through time of four angles commonly used in clinical practice were calculated.Results:The coefficients of determination for SNA,ANB,NAPg and UI/SN stepwise regression were 0.96,0.95,0.39 and 0.99 respectively.Conclusion:There may be more extra landmark noise associated with the measurement of angle NAPg than with the other three angles.Since change in SNA is affected by Nasion horizontal displacement,its representation of Point A displacement was questionable.
出处
《实用口腔医学杂志》
CAS
CSCD
北大核心
2000年第2期90-92,共3页
Journal of Practical Stomatology
